Patent Publication Number: US-2022239058-A1

Title: Semiconductor laser device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation application of PCT International Application No. PCT/JP2020/039828 filed on Oct. 23, 2020, designating the United States of America, which is based on and claims priority of Japanese Patent Application No. 2019-193503 filed on Oct. 24, 2019. The entire disclosures of the above-identified applications, including the specifications, drawings, and claims are incorporated herein by reference in their entirety. 
    
    
     FIELD 
     The present disclosure relates to a semiconductor laser device. 
     BACKGROUND 
     Conventionally, semiconductor laser elements with increasingly higher output power continue to be developed and are attracting attention as highly efficient laser light sources for laser processing. As the output power of the semiconductor laser elements increases, so does the current supplied to the semiconductor laser element. In order to reduce heat generation that accompanies the increase in supplied current, the wire used to supply the current must have low resistance, One conceivable method of lowering the resistance of the wire is to increase the thickness of the wire, but since the size of the electrode of the semiconductor laser element is restricted, there is a limit to the thickness of wire that can be used. 
     In view of this, a technique for supplying current using a plurality of wires has been proposed (see Patent Literature (PTL) 1). In the invention disclosed by PTL 1, the submount and the electrodes of the semiconductor laser element are connected using a plurality of wires spaced at equal intervals. This reduces the electrical resistance from the submount to the electrodes of the semiconductor laser element more so than when a single wire is used. 
     CITATION LIST 
     Patent Literature 
     PTL  1 : Japanese Unexamined Patent Application Publication No. 2003-198051 
     SUMMARY 
     Technical Problems 
     Unfortunately, with the semiconductor laser element disclosed in PTL 1, there are cases in which the plurality of wires are not arranged in appropriate positions. For example, when the plurality of wires are unevenly arranged on an electrode of the semiconductor laser element, the current is not uniformly supplied to the active layer of the semiconductor laser element. Although the current may be, for example, diffused in the electrode to evenly supply current to the active layer of the semiconductor laser element even when the plurality of wires are unevenly arranged, the electrode is not thick enough to sufficiently diffuse the current. 
     When current is not evenly supplied to the active layer, problems may arise such as a reduction in the output power of the laser beam. Moreover, even when the plurality of wires are unevenly disposed to one part of the submount, this may cause current to be unevenly supplied to the semiconductor laser element. In such cases, heat transmitted by the wires concentrates in that part of the submount, reducing the heat dissipation efficiency of the submount. 
     The present disclosure was conceived in view of the above problems, and has an object to, in a semiconductor laser device in which current is supplied to a semiconductor laser element using a plurality of wires, arrange the plurality of wires in appropriate positions. 
     Solution to Problems 
     In order to overcome the problems described above, a semiconductor laser device according to one aspect of the present disclosure includes: a substrate including a main surface on which a metal film is formed; a semiconductor laser element that is disposed on the main surface and includes a resonator extending along a first direction among in-plane directions of the main surface; and a plurality of first wire groups arranged along the first direction. Each of the plurality of first wire groups includes a first wire and a first mark portion, The first wire is bonded to a first bonding region of a top surface of the semiconductor laser element, and the first mark portion is formed on the main surface. The main surface has a rectangular shape including a first side extending along the first direction, a second side disposed on an opposite side of the first side across the semiconductor laser element and extending along the first direction, and a third side perpendicular to the first side and the second side. In a top view of the main surface, the first wire intersects the first side, and the first wire is disposed at a position overlapping the first mark portion. 
     This allows the first wires to be placed at appropriate positions by placing the first mark portions at appropriate placement positions for the respective first wires in the top view of the main surface. By inspecting whether the first wires overlap the respective first mark portions in the top view of the main surface, it is possible to determine whether the position of each first wire is acceptable or not acceptable. Evenly distributing the first wires along the first direction makes it possible to supply current evenly to the semiconductor laser element. 
     In order to overcome the problems described above, a semiconductor laser device according to another aspect of the present disclosure includes: a substrate including a main surface on which a metal film is formed; a semiconductor laser element that is disposed on the main surface and includes a resonator extending along a first direction among in-plane directions of the main surface; and a plurality of second wire groups arranged along the first direction. Each of the plurality of second wire groups includes a second wire and a second mark portion. The second wire is bonded to a second bonding region of the main surface, and the second mark portion is formed on the main surface. The main surface has a rectangular shape including a first side extending along the first direction, a second side disposed on an opposite side of the first side across the semiconductor laser element and extending along the first direction, and a third side perpendicular to the first side and the second side. The second bonding region is disposed between the semiconductor laser element and the second side. In a top view of the main surface, the second wire intersects the second side, and at least one of the second bonding region or the second wire is disposed at a position overlapping the second mark portion. 
     This allows the second wires to be placed at appropriate positions by placing the second mark portions at appropriate placement positions for the respective second wires in the top view of the main surface. By inspecting whether the second wires overlap the respective second mark portions in the top view of the main surface, it is possible to determine whether the position of each second wire is acceptable or not acceptable. Evenly distributing the second wires along the first direction makes it possible to supply current evenly to the semiconductor laser element. 
     In one aspect, the semiconductor laser device according to the present disclosure may further include a plurality of second wire groups arranged along the first direction. Each of the plurality of second wire groups may include a second wire and a second mark portion. The second wire may be bonded to a second bonding region of the main surface, and the second mark portion may be formed on the main surface. The second bonding region may be disposed between the semiconductor laser element and the second side. In the top view of the main surface, the second wire may intersect the second side, and at least one of the second bonding region or the second wire may be disposed at a position overlapping the second mark portion. 
     This allows the second wires to be placed at appropriate positions by placing the second mark portions at appropriate placement positions for the respective second wires in the top view of the main surface. By inspecting whether the second wires overlap the respective second mark portions in the top view of the main surface, it is possible to determine whether the position of each second wire is acceptable or not acceptable. Evenly distributing the first and second wires along the first direction makes it possible to supply current evenly to the semiconductor laser element. 
     In one aspect of the semiconductor laser device according to the present disclosure, in the top view of the main surface, the first mark portion may include a first mark disposed directly below the first wire. 
     This makes it easy to determine whether the positions of the first wires are acceptable or not acceptable by simply inspecting whether or not the first wires and the first marks overlap. Moreover, recognizing the first marks during wire bonding makes it easier to place the first wires in the appropriate positions. 
     In one aspect of the semiconductor laser device according to the present disclosure, in the top view of the main surface, the first mark portion may include two first marks disposed spaced apart from each other and a line segment connecting the two first marks, and the first wire may overlap the line segment connecting the two first marks. 
     This makes it possible to form a first mark portion including two first marks that is larger than each of the two first marks. Accordingly, for example, when the first mark is formed by removing the metal film from the main surface, the region in which the metal film is removed can be reduced and the first mark portion can be enlarged. This makes it possible to both inhibit uneven current resulting from removing the metal film and enlarge the first mark portion. 
     In one aspect of the semiconductor laser device according to the present disclosure, the first mark portion may include a first mark formed in the metal film. 
     Forming the first mark portion in the metal film in this manner eliminates the need to add other components to form the first mark. For example, the first mark is formed by removing a portion of the metal film. 
     In one aspect of the semiconductor laser device according to the present disclosure, the first mark may be in contact with, among outer edges of the metal film, an outer edge closest to the first side. 
     Removing the metal film makes it possible to inhibit uneven current resulting from removing the metal film. 
     In one aspect of the semiconductor laser device according to the present disclosure, in the top view of the main surface, the second mark portion may include a second mark disposed directly below the second wire. 
     In one aspect of the semiconductor laser device according to the present disclosure, in the top view of the main surface, the second mark portion may include two second marks disposed spaced apart from each other and a line segment connecting the two second marks, and the second wire may overlap the line segment connecting the two second marks. 
     This makes it possible to form a second mark portion including two second marks that is larger than each of the two second marks. Accordingly, for example, when the second mark is formed by removing the metal film from the main surface, the region in which the metal film is removed can be reduced and the second mark portion can be enlarged. This makes it possible to both inhibit uneven current resulting from removing the metal film and enlarge the second mark portion. 
     In one aspect of the semiconductor laser device according to the present disclosure, in the top view of the main surface, the second mark portion may include two second marks disposed spaced apart from each other, and the second bonding region may overlap a line segment connecting the two second marks. 
     This makes it possible to form a second mark portion including two second marks that is larger than each of the two second marks. Accordingly, for example, when the second mark is formed by removing the metal film from the main surface, the region in which the metal film is removed can be reduced and the second mark portion can be enlarged. This makes it possible to both inhibit uneven current resulting from removing the metal film and enlarge the second mark portion. 
     In one aspect of the semiconductor laser device according to the present disclosure, the second mark portion may include a second mark formed in the metal film. 
     Forming the second mark portion in the metal film in this manner eliminates the need to add other components to form the second mark. For example, the second mark is formed by removing a portion of the metal film. 
     In one aspect of the semiconductor laser device according to the present disclosure, the second mark may be in contact with, among outer edges of the metal film, an outer edge closest to the second side. 
     Disposing the second mark at an outer edge of the metal film in this manner prevents the second mark from interfering with the second bonding region. Moreover, since the second mark is disposed at an outer edge of the metal film, the second mark can be separated from the second bonding region to a relatively large extent, and the effect that forming the second mark has on the current flowing in the metal film can be reduced. 
     In one aspect, the semiconductor laser device according to the present disclosure may further include a third mark formed on the main surface. In the top view of the main surface, the third mark may overlap a straight line passing through and parallel to a front end face of the semiconductor laser element. 
     This enables the alignment of the front end face of the semiconductor laser element based on the third mark. 
     In one aspect, the semiconductor laser device according to the present disclosure may further include a third mark formed on the main surface. In the top view of the main surface, the third mark may overlap a straight line passing through and parallel to a front end face of the semiconductor laser element. The third mark may be disposed closer to the third side than the first mark portion and the second mark portion are. 
     In one aspect, the semiconductor laser device according to the present disclosure may further include a fourth mark formed on the main surface. In the top view of the main surface, the fourth mark may overlap a straight line passing through and parallel to a rear end face of the semiconductor laser element. 
     This enables the alignment of the rear end face of the semiconductor laser element based on the fourth mark. 
     In one aspect, the semiconductor laser device according to the present disclosure may further include a third mark formed on the main surface and a fourth mark formed on the main surface. In the top view of the main surface, the third mark may overlap a straight line passing through and parallel to a front end face of the semiconductor laser element. In the top view of the main surface, the fourth mark may overlap a straight line passing through and parallel to a rear end face of the semiconductor laser element. The second bonding region may be disposed on a straight line connecting the third mark and the fourth mark. 
     By arranging the third mark and the fourth mark on a straight line passing through the appropriate placement position of the second bonding region, it is possible to arrange the second bonding region in the appropriate position, By inspecting whether or not the second bonding region is arranged on a straight line connecting the third mark and the fourth mark in the top view of main surface, it is possible to determine whether the position of the second bonding region is acceptable or not acceptable. 
     In one aspect of the semiconductor laser device according to the present disclosure, the semiconductor laser element may include an electrode disposed on the top surface. The electrode may include a plurality of bonding portions and one or more intermediate portions. Each of the one or more intermediate portions may be disposed between two adjacent bonding portions among the plurality of bonding portions. A width in a second direction perpendicular to the first direction of each of the plurality of bonding portions may be greater than a width in the second direction of each of the one or more intermediate portions. 
     Making the width in the second direction at each bonding portion greater than the width in the second direction at each intermediate portion facilitates bonding of the wires to the respective bonding portions, In addition, by making the widths of the bonding portions and the intermediate portions in the second direction different, each bonding portion can be easily identified, which makes it easy to determine whether or not a wire is bonded to each bonding portion. Moreover, using the difference in widths between the bonding portions and the intermediate portions in pattern recognition makes it possible to prevent wires from protruding from the bonding portions. 
     In one aspect of the semiconductor laser device according to the present disclosure, among the plurality of bonding portions, the distance from a bonding portion closest to a front end face of the semiconductor laser element to the front end face may be shorter than the distance from a bonding portion closest to a rear end face of semiconductor laser element to the rear end face. 
     With this, a bonding portion can be positioned close to the front end face, which is likely to consume the largest amount of current in the semiconductor laser element, which means that current can be efficiently supplied to the region close to the front end face. 
     In one aspect of the semiconductor laser device according to the present disclosure, the semiconductor laser element may include a chip identification mark disposed in, among regions of the electrode, a region closer to the rear end face than to the front end face. 
     This makes it possible to identify the semiconductor laser element. Moreover, the vicinity of the rear end face of the semiconductor laser element consumes no more current than the vicinity of the front end face. Therefore, placing the chip identification mark in the vicinity of the rear end face reduces the effect on the output of the semiconductor laser element more so than when the chip identification mark is placed in the vicinity of the front end face. 
     In one aspect of the semiconductor laser device according to the present disclosure, the first bonding regions corresponding to the plurality of first wire groups may be arranged in a staggered arrangement along the first direction. 
     By arranging the first bonding regions in this manner, more first bonding regions can be provided on the electrode of the semiconductor laser element while inhibiting each first bonding region (i.e., each first wire) from interfering with each other. Accordingly, more heat can be dissipated from the semiconductor laser element through the first bonding regions and the first wires, thereby increasing the heat dissipation efficiency of the semiconductor laser device. 
     In one aspect of the semiconductor laser device according to the present disclosure, the second bonding regions corresponding to the plurality of second wire groups may be arranged in a staggered arrangement along the first direction. 
     By arranging the second bonding regions in this manner, more second bonding regions can be provided on the main surface of the substrate while inhibiting each second bonding region (i.e., each second wire) from interfering with each other. Accordingly, more heat can be dissipated from the substrate through the second bonding regions and the second wires, thereby increasing the heat dissipation efficiency of the semiconductor laser device. 
     In one aspect of the semiconductor laser device according to the present disclosure, each of the plurality of second wire groups may include one or more second marks, and the one or more second marks of the plurality of second wire groups may be arranged in a staggered arrangement along the first direction. 
     In one aspect of the semiconductor laser device according to the present disclosure, the total number of the plurality of second wire groups may be greater than the total number of the plurality of first wire groups. 
     This allows the current supplied to each second wire to be reduced. 
     In one aspect, the semiconductor laser device according to the present disclosure may further include a bonding member that bonds the main surface and the semiconductor laser element. 
     In one aspect, the semiconductor laser device according to the present disclosure may further include a bonding member that bonds the main surface and the semiconductor laser element. The distance from the second bonding region to the bonding member may be shorter than the distance from the second bonding region to the second side. 
     This allows each second bonding region to be brought closer to the semiconductor laser element, which is a heat source, so heat can be efficiently dissipated via each second wire. Bringing each second bonding region closer to the semiconductor laser element also reduces the resistance component between each second bonding region and the semiconductor laser element. Accordingly, the power conversion efficiency of the semiconductor laser device can be increased. 
     In one aspect of the semiconductor laser device according to the present disclosure, the distance from the bonding member to the first side may be shorter than the distance from the bonding member to the second side. 
     With this, the distance from the semiconductor laser element to the first side can be made shorter than the distance from the semiconductor laser element to the second side. As a result, the surface area of the region of the main surface from semiconductor laser element to the second side is larger than when the distances from the semiconductor laser element to the first side and the second side are equal. Accordingly, it is possible to dispose more second wires (i.e., second bonding regions) in the region of the main surface from the semiconductor laser element to the second side. 
     In one aspect of the semiconductor laser device according to the present disclosure, the distance from the semiconductor laser element to the first side may be shorter than the distance from the semiconductor laser element to the second side. 
     As a result, the surface area of the region of the main surface from semiconductor laser element to the second side is larger than when the distances from the semiconductor laser element to the first side and the second side are equal. Accordingly, it is possible to dispose more second wires (i.e., second bonding regions) in the region of the main surface from the semiconductor laser element to the second side. 
     Advantageous Effects 
     According to the present disclosure, in a semiconductor laser device in which current is supplied to a semiconductor laser element using a plurality of wires, it is possible to arrange the plurality of wires in appropriate positions. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       These and other advantages and features will become apparent from the following description thereof taken in conjunction with the accompanying Drawings, by way of non-limiting examples of embodiments disclosed herein. 
         FIG. 1  is a schematic front view illustrating the overall configuration of a semiconductor laser device according to Embodiment 1. 
         FIG. 2  is a schematic top view illustrating the overall configuration of the semiconductor laser device according to Embodiment 1. 
         FIG. 3  is a schematic top view illustrating a configuration of a semiconductor laser element and a substrate according to Embodiment 1. 
         FIG. 4  is a schematic top view illustrating configurations of a plurality of first wire groups and a plurality of second wire groups of the semiconductor laser device according to Embodiment 1. 
         FIG. 5  is a schematic diagram illustrating the region indicated by a second mark portion according to Embodiment 1. 
       FIG,  6  is a schematic cross sectional view illustrating a configuration of the semiconductor laser element according to Embodiment 1 before being bonded to the substrate. 
         FIG. 7  is a schematic cross sectional view illustrating a configuration of the semiconductor laser element according to Embodiment 1 after being bonded to the substrate. 
         FIG. 8  is a schematic front view illustrating a first process of a manufacturing method of the semiconductor laser device according to Embodiment 1. 
         FIG. 9  is a schematic front view illustrating a second process of the manufacturing method of the semiconductor laser device according to Embodiment 1. 
         FIG. 10  is a schematic front view illustrating a third process of the manufacturing method of the semiconductor laser device according to Embodiment 1. 
         FIG. 11  is a schematic front view illustrating a fourth process of the manufacturing method of the semiconductor laser device according to Embodiment 1. 
         FIG. 12  is a schematic front view illustrating the overall configuration of a semiconductor laser device according to Embodiment 2. 
         FIG. 13  is a schematic top view illustrating the overall configuration of the semiconductor laser device according to Embodiment 2. 
         FIG. 14  is a schematic top view illustrating a configuration of a semiconductor laser element and a substrate according to Embodiment 2. 
         FIG. 15  is a schematic top view illustrating configurations of a plurality of first wire groups and a plurality of second wire groups of the semiconductor laser device according to Embodiment 2. 
         FIG. 16  is a schematic top view illustrating the structure of an electrode of the semiconductor laser element according to Embodiment 2. 
         FIG. 17  is a schematic cross sectional view illustrating a configuration of the semiconductor laser element according to Embodiment 2 before being bonded to the substrate. 
         FIG. 18  is a schematic cross sectional view illustrating a configuration of the semiconductor laser element according to Embodiment 2 after being bonded to the substrate. 
         FIG. 19  is a schematic front view illustrating a first process of a manufacturing method of the semiconductor laser device according to Embodiment 2. 
         FIG. 20  is a schematic front view illustrating a second process of the manufacturing method of the semiconductor laser device according to Embodiment 2. 
         FIG. 21  is a schematic front view illustrating a third process of the manufacturing method of the semiconductor laser device according to Embodiment 2. 
         FIG. 22  is a schematic front view illustrating a fourth process of the manufacturing method of the semiconductor laser device according to Embodiment 2. 
         FIG. 23  is a schematic front view illustrating a fifth process of the manufacturing method of the semiconductor laser device according to Embodiment 2. 
         FIG. 24  is a schematic top view illustrating a configuration of a semiconductor laser device according to Embodiment 3. 
         FIG. 25  is a schematic top view illustrating configurations of a plurality of first mark portions and a plurality of second mark portions of the semiconductor laser device according to Embodiment 3. 
         FIG. 26  is a schematic top view illustrating configurations of a plurality of first wire groups and a plurality of second wire groups according to Embodiment 3. 
         FIG. 27  is a schematic top view illustrating a configuration of a semiconductor laser device according to Embodiment 4. 
         FIG. 28  is a schematic top view illustrating configurations of a plurality of first mark portions and a plurality of second mark portions of the semiconductor laser device according to Embodiment 4. 
         FIG. 29  is a schematic top view illustrating configurations of a plurality of first wire groups and a plurality of second wire groups according to Embodiment 4. 
         FIG. 30  is a schematic top view illustrating a variation of the plurality of second mark portions of the semiconductor laser device according to Embodiment 3. 
         FIG. 31  is a schematic top view illustrating a plurality of second mark portions of a semiconductor laser device according to a variation of Embodiment 3. 
         FIG. 32  is a schematic top view illustrating a plurality of first mark portions and a plurality of second mark portions of a semiconductor laser device according to a variation of Embodiment 2. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments will be described with reference to the drawings, Each of the following embodiments shows a specific example of the present disclosure. The numerical values, shapes, materials, elements, the arrangement and connection of the elements, etc., indicated in the following embodiments are mere examples, and therefore do not intend to limit the present disclosure. 
     The figures are schematic illustrations and are not necessarily precise depictions. Accordingly, the figures are not necessarily to scale. In the figures, elements that are essentially the same share like reference signs. Accordingly, duplicate description is omitted or simplified. 
     Moreover, in the present specification, the terms “above” and “below” do not refer to the upward (vertically upward) direction and downward (vertically downward) direction in terms of absolute spatial recognition, but are used as terms defined by relative positional relationships based on the stacking order of a stacked configuration. Furthermore, the terms “above” and “below” are applied not only when two elements are disposed with a gap therebetween or when a separate element is interposed between two elements, but also when two elements are disposed in contact with each other. 
     Embodiment 1 
     A semiconductor laser device according to Embodiment 1 will be described. 
     1-1. Overall Configuration 
     First, the overall configuration of the semiconductor laser device according to the present embodiment will be described with reference to  FIG. 1  through  FIG. 3 .  FIG. 1  and  FIG. 2  are schematic front and top views, respectively, illustrating the overall configuration of semiconductor laser device  10  according to the present embodiment.  FIG. 3  is a schematic top view illustrating a configuration of semiconductor laser element  20  and substrate  80  according to the present embodiment. In  FIG. 1  through  FIG. 3 , the direction of emission of the laser beam by semiconductor laser device is defined as the Y-axis direction, the direction that is perpendicular the Y-axis direction and perpendicular to the surface on which semiconductor laser element  20  of substrate  80  is provided is defined as the Z-axis direction, and the direction perpendicular to the Y-axis direction and the Z-axis direction is defined as the X-axis direction. In each figure, the positive directions of the X-, Y-, and Z-axes are depicted in a right-handed coordinate system. The same applies to the figures presented below. 
     Semiconductor laser device  10  is a device that emits a laser beam and, as illustrated in  FIG. 1  and  FIG. 2 , includes substrate  80  and semiconductor laser element  20 . As illustrated in  FIG. 2 , semiconductor laser device  10  further includes first wires  61  through  64 , second wires  71  through  74 , lead pins  91 ,  92 , and  95 , stem  93 , and base  94 . Although not illustrated in  FIG. 1  through  FIG. 3 , semiconductor laser device  10  may include a cap that covers of semiconductor laser element  20 , substrate  80 , and stem  93 . 
     Base  94  is the base of semiconductor laser device  10 . In the present embodiment, base  94  is an electrically conductive member having a disc-like shape. 
     Lead pins  91 ,  92  and  95  are terminals for supplying current to semiconductor laser element  20 . In the present embodiment, a high potential is applied to lead pin  91  and a low potential is applied to lead pins  92  and  95 . Lead pins  91 ,  92  and  95  are electrical conductors having a cylindrical shape. Lead pins  91  and  92  penetrate base  94 . Lead pin  95  is erected on the surface of base  94  opposite the surface on which stem  93  is disposed. 
     Lead pin  91  is electrically insulated from base  94 , More specifically, lead pin  91  is fixed to base  94  via an insulating member (not illustrated in the drawings). Lead pins  92  and  95  are fixed to base  94  in an electrically conductive state with base  94 . 
     Stem  93  is a plate-like member erected on base  94 . In the present embodiment, stem  93  also functions as a heat sink for semiconductor laser element  20 . 
     The electrically conductive material included in base  94 , lead pins  91 ,  92  and  95 , and stem  93  is not particularly limited. For example, the electrically conductive material is aluminum alloy or Cu or the like. 
     Semiconductor laser element  20  is a semiconductor element that generates a laser beam. As illustrated in  FIG. 3 , semiconductor laser element  20  is disposed on main surface  80   a  of substrate  80  and includes a resonator extending along a first direction among in-plane directions of main surface  80   a.  In the present embodiment, the resonator of semiconductor laser element  20  is formed with front end face  20 F and rear end face  20 R. Front end face  20 F is the end face on the end of semiconductor laser element  20  from which the laser beam is emitted, and has a lower reflectance to the laser beam than rear end face  20 R. Rear end face  20 R is a highly reflective end face that reflects the laser beam of semiconductor laser element  20 . The first direction is the direction in which the laser beam resonates, i.e., the direction in which the laser beam is emitted, and is parallel to the Y-axis direction in each figure. 
     Electrode  28  is formed on the top surface of semiconductor laser element  20  (i.e., the surface opposite the surface bonded to substrate  80 ). The top surface of semiconductor laser element  20  includes first bonding regions B 11  through  814  to which first wires  61  through  64  are respectively bonded. Semiconductor laser element  20  according to the present embodiment is junction-up mounted on main surface  80   a  of substrate  80 . In other words, the substrate-side surface of semiconductor laser element  20  is mounted to main surface  80   a,  and the optical waveguide is disposed directly below the top surface of semiconductor laser element  20 . Since the first wires are respectively bonded to the first bonding regions in this configuration, there is a risk that ridge portion  23 R forming the optical waveguide of semiconductor laser element  20  may be damaged by impact when bonding the first wires. In order to inhibit such damage, each first bonding region is disposed in a region that is not directly above ridge portion  23 R. If each of the first bonding regions is arranged in a region that is not directly above ridge portion  23 R, it may not be possible to secure enough space width-wise (that is, secure enough space in the X-axis direction dimension in the figures) for each first bonding region. Accordingly, in the present embodiment, ridge portion  23 R is offset in a second direction (X-axis direction in the figures) that is perpendicular to the first direction and parallel to the top surface. In the example illustrated in  FIG. 3 , ridge portion  23 R is offset from the center of semiconductor laser element  20  toward second side  82  of main surface  80   a  of substrate  80 . This allows for the width of each first bonding region to be increased. When semiconductor laser element  20  is junction-up mounted on main surface  80   a  as described above, the width of each first bonding region is more restricted than when semiconductor laser element  20  is junction-down mounted, and thus the diameter of each first wire is also restricted. Therefore, reducing the combined resistance in the first wires by increasing the number of first wires to increase the amount of current supplied to semiconductor laser element  20  that is mounted junction-up is even more necessary than when semiconductor laser element  20  is mounted junction-down. 
     In the present embodiment, first bonding regions B 11  through B 14  are arranged in parallel in the first direction. The distances from front end face  20 F of semiconductor laser element  20  to the respective centers of first bonding regions B 11  through B 14  are 0.14 mm, 0.29 mm, 0.49 mm, and 0.64 mm, respectively. 
     Semiconductor laser element  20  is bonded to metal film  86  on main surface  80   a  of substrate  80  by bonding member  88 . The configuration of bonding member  88  is not particularly limited. In the present embodiment, bonding member  88  includes, in order from the metal film  86  side, a 0.32 μm thick Pt film and a 2.5 μm thick solder film comprising AuSn. The length of bonding member  88  in the second direction is approximately 0.25 mm. 
     The size and structure of semiconductor laser element  20  are not particularly limited. In the present embodiment, the length of the resonator of semiconductor laser element  20  is 800 μm, the width in second direction is 150 μm, and the thickness (the Z-axis direction dimension) is 85 μm. 
     The stacked structure of semiconductor laser element  20  will be described later. 
     Substrate  80  is a submount on which semiconductor laser element  20  is provided. Substrate  80  also functions as a heat sink for semiconductor laser element  20 . Although the material included in substrate  80  is not particularly limited so long as the material has a high thermal conductivity, in the present embodiment, the material is SiC. 
     As illustrated in  FIG. 3 , substrate  80  includes main surface  80   a  on which metal film  86  is formed. Although the size and shape of substrate  80  are not particularly limited, in the present embodiment, substrate  80  has a rectangular shape with a length (i.e., a Y-axis direction dimension) of 0.93 mm, a width (i.e., an X-axis direction dimension) of 0.55 mm, and a thickness (i.e., a Z-axis direction dimension) of 0.19 mm. 
     The shape of main surface  80   a  is a rectangle including first side  81  extending along the first direction, second side  82  disposed on the opposite side of first side  81  across semiconductor laser element  20  and extending along the first direction, and third side  83  and fourth side  84  perpendicular to first side  81  and second side  82 . 
     Main surface  80   a  includes second bonding regions B 21  through B 24  to which second wires  71  through  74  are respectively bonded. Each second bonding region is disposed between semiconductor laser element  20  and second side  82  of main surface  80   a.  In the present embodiment, second bonding regions B 21  through B 24  are aligned spaced at equal intervals and parallel to the first direction. Second bonding regions B 21  through B 24  are spaced at 0.15 mm intervals. The distance from third side  83  of main surface  80   a  to the center of second bonding region B 21  is 0.23 mm, and the distance from fourth side  84  to the center of second bonding region B 24  is 0.25 mm. The distance from second side  82  of main surface  80   a  to each second bonding region is 0.07 mm. 
     Metal film  86  is an electrically conductive film that is connected to one electrode of semiconductor laser element  20 . Metal film  86  is not particularly limited as long as it is an electrically conductive film. In the present embodiment, metal film  86  includes, in order from main surface  80   a  of substrate  80 , a 0.1 μm thick Ti film, a 0.2 μm thick Pt film, and a 0.5 μm thick Au film. Metal film  86  is not formed in a 0.01 mm wide region at the edge of main surface  80   a.    
     First marks  41  through  44 , second marks  51  through  55 , third marks  31  and  32 , and fourth mark  33  are formed in metal film  86 , Forming marks in metal film  86  in this manner eliminates the need to add other components to form marks. Each mark is configured to be visible on main surface  80   a.  In the present embodiment, each mark is formed by removing a portion of metal film  86  from the Au film to the Ti film to expose main surface  80   a  from beneath metal film  86 . As a result, each mark is visible due to the contrast between (i.e., the difference in reflectance to visible light) between each mark portion and other portions of main surface  80   a.  The configuration of each mark is not particularly limited as long as it is visible. For example, each mark may be formed by placing another film on metal film  86  that has a different reflectance than metal film  86 . The minimum size of each mark is set to a size that allows each mark to be easily formed and visible. Note that each mark does not need to be visible to the naked eye. For example, each mark may be visible under a microscope. The maximum size of each mark is set to secure sufficient space for bonding each wire, etc. 
     Each first mark is disposed between semiconductor laser element  20  and first side  81  of main surface  80   a.  In the present embodiment, each first mark has a quadrangular shape. The width of each first mark in the first direction is approximately 20 μm to 70 μm, inclusive. The length of each first mark in the second direction perpendicular to the first direction is approximately 20 μm to 140 μm, inclusive, Each first mark has a quadrangular shape and is in contact with the outer edge of metal film  86  on the first side  81  side of main surface  80   a  (in other words, the outer edge of metal film  86  that is closest to first side  81 ). Stated differently, each first mark is a notch formed inwardly from the first side  81  side end portion of metal film  86 . 
     In the top view of main surface  80   a,  first marks  41  through  44  are disposed directly below first wires  61  through  64 , respectively. In the present embodiment, the distances from third side  83  of main surface  80   a  to the first direction centers of first marks  41  through  44  are 0.205 mm, 0.355 mm, 0.555 mm, and 0.705 mm, respectively. The distance from fourth side  84  of main surface  80   a  to first mark  44  is 0.225 mm. 
     Each second mark is disposed between semiconductor laser element  20  and second side  82  of main surface  80   a.  In the present embodiment, each second mark has a triangular shape. More specifically, each second mark has the shape of an isosceles right triangle and is formed at an angle such that the hypotenuse is parallel to second side  82  of main surface  80   a.  The length of the two perpendicular sides of each second mark is approximately 25 μm to 100 μm, inclusive. Each second mark has a triangular shape and is in contact with the outer edge of metal film  86  on the second side  82  side of main surface  80   a.  Stated differently, each second mark is a notch formed inwardly from the second side  82  side end portion of metal film  86 . Disposing each second mark at an outer edge of metal film  86  in this manner prevents the second marks from interfering with the second bonding regions. Moreover, since each second mark is disposed at an outer edge of metal film  86 , the second marks can be separated from the second bonding regions to a relatively large extent, and the effect that forming each second mark has on the current flowing in metal film  86  can be reduced. 
     In the present embodiment, the distances from third side  83  of main surface  80   a  to the first direction centers of second marks  51  through  55  are 0.15 mm, 0.30 mm, 0.45 mm, 0.60 mm, and 0.75 mm, respectively. Second marks  51  through  55  are thus arranged spaced at equal intervals. The distance from fourth side  84  of main surface  80   a  to second mark  55  is 0.17 mm. 
     Each third mark is a mark formed on main surface  80   a,  and in the top view of main surface  80   a,  each third mark overlaps a straight line passing through and parallel to front end face  20 F of semiconductor laser element  20 . This enables the alignment of front end face  20 F of semiconductor laser element  20  based on each third mark. In the present embodiment, the distance from third side  83  of main surface  80   a  to the center of each third mark is 0.065 mm. The distance from first side  81  of main surface  80   a  to the center of third mark  31  and the distance from second side  82  to the center of third mark  32  are both 0.07 mm. Each third mark is thus disposed closer to the third side  83  of main surface  80   a  than any of the first and second marks are. 
     Although the shape of each third mark is not particularly limited, in the present embodiment, each third mark has a square shape and each side of the square is inclined at 45 degrees relative to each side of main surface  80   a.  The length of each side of each third mark is approximately 30 μm to 70 μm, inclusive. Although two third marks  31  and  32  are exemplified as being formed in the present embodiment, one third mark may be formed, and third marks  31  and  32  may not be formed. 
     Fourth mark  33  is a mark formed on main surface  80   a,  and in the top view of main surface  80   a,  fourth mark  33  overlaps a straight line passing through and parallel to rear end face  20 R of semiconductor laser element  20 . This enables the alignment of rear end face  20 R of semiconductor laser element  20  based on fourth mark  33 . In the present embodiment, the distance from fourth side  84  of main surface  80   a  to the center of fourth mark  33  is 0.065 mm. The distance from second side  82  of main surface  80   a  to the center of fourth mark  33  is 0.07 mm. 
     Although the shape of fourth mark  33  is not particularly limited, in the present embodiment, fourth mark  33  has a square shape and each side of the square is inclined at  45  degrees relative to each side of main surface  80   a.  The length of one side of fourth mark  33  is approximately 30 μm to 70 μm, inclusive. 
     Although one fourth mark  33  is exemplified as being formed in the present embodiment, two fourth marks may be formed, and no fourth mark  33  may be formed. 
     In the present embodiment, each second bonding region is disposed on a straight line connecting third mark  32  and fourth mark  33 . By arranging third mark  32  and fourth mark  33  on a straight line passing through the appropriate placement position of each second bonding region, it is possible to arrange each second bonding region in the appropriate position. By inspecting whether or not each second bonding region is arranged on a straight line connecting third mark  32  and fourth mark  33  in the top view of main surface  80   a,  it is possible to determine whether the position of the second bonding region is acceptable or not acceptable. 
     As illustrated in  FIG. 3 , semiconductor laser device  10  according to the present embodiment includes a plurality of first mark portions M 11  through M 14  and a plurality of second mark portions M 21  through M 24 . First mark portions M 11  through M 14  include first marks  41  through  44 , respectively. In other words, first mark portion Mil includes first mark  41 , first mark portion M 12  includes first mark  42 , first mark portion M 13  includes first mark  43 , and first mark portion M 14  includes first mark  44 . Second mark portion M 21  includes second marks  51  and  52 , second mark portion M 22  includes second marks  52  and  53 , second mark portion M 23  includes second marks  53  and  54 , and second mark portion M 24  includes second marks  54  and  55 . 
     First mark portions M 11  through M 14  are mutually different. Stated differently, at least part of the one or more first marks included in each of first mark portions M 11  through M 14  is different, Second mark portions M 21  through M 24  are mutually different. Stated differently, at least part of the one or more second marks included in each of second mark portions M 21  through M 24  is different. 
     Although not illustrated in the drawings, a metal film is also formed on the main surface that is on the opposite side of main surface  80   a  of substrate  80 . In the present embodiment, a 0.1 μm thick Ti film, a 0.2 μm thick Pt film, and a 0.5 μm thick Au film are formed in the listed order from the substrate  80  side. 
     Substrate  80  is bonded to one surface of stem  93  by bonding member  87 . The configuration of bonding member  87  is not particularly limited, In the present embodiment, bonding member  87  includes a 4.0 μm thick solder film comprising AuSn. 
     As illustrated in  FIG. 2 , first wires  61  through  64  are electrically conductive wires for supplying current that connect lead pin  91  to semiconductor laser element  20 . As illustrated in  FIG. 3 , first wires  61  through  64  are bonded to first bonding regions B 11  through B 14  of the top surface of semiconductor laser element  20 , respectively. First wires  61  through  64  respectively include, at end portions on the semiconductor laser element  20  side, first ball portions  61 B through  64 B having a hemispherical shape. First ball portions  61 B through  64 B are bonded to the top surface of semiconductor laser element  20  at first bonding regions B 11  through B 14 , respectively. In the top view of main surface  80   a,  each first wire intersects first side  81  of main surface  80   a.    
     The material and structure of each first wire is not particularly limited. In the present embodiment, each first wire is a 20 μm diameter wire comprising Au. The diameter of each first ball portion is approximately 55±15 μm. The diameter of each first wire may be greater than or equal to 15 μm and 50 μm or less. The diameter of each first ball portion may be greater than or equal to 30 μm and 100 μm or less. 
     As illustrated in  FIG. 2 , second wires  71  through  74  are wires for supplying current that connect lead pin  92  to main surface  80   a  of substrate  80 . As illustrated in  FIG. 3 , second wires  71  through  74  are bonded to second bonding regions B 21  through B 24  of main surface  80   a  of substrate  80 , respectively. Second wires  71  through  74  respectively include, at end portions on the main surface  80   a  side, second ball portions  71 B through  74 B having a hemispherical shape. Second ball portions  71 B through  74 B are bonded to main surface  80   a  at second bonding regions B 21  through B 24 , respectively. In the top view of main surface  80   a,  each second wire intersects second side  82  of main surface  80   a.    
     The material and structure of each second wire is not particularly limited, In the present embodiment, each second wire is a 20 μm diameter wire comprising Au, The diameter of each second ball portion is approximately 55±15 μm, The diameter of each second wire may be greater than or equal to 15 μm and 50 μm or less. The diameter of each second ball portion may be greater than or equal to 30 μm and 100 μm or less. 
     1-2. Configuration of First Wire Group and Second Wire Group 
     Semiconductor laser device  10  according to the present embodiment includes a plurality of first wire groups and a plurality of second wire groups. The configurations of each of the plurality of first wire groups and the plurality of second wire groups according to the present embodiment will be described below with reference to  FIG. 4 .  FIG. 4  is a schematic top view illustrating configurations of a plurality of first wire groups G 11  through G 14  and a plurality of second wire groups G 21  through G 24  of semiconductor laser device  10  according to the present embodiment. 
     As illustrated in  FIG. 4 , semiconductor laser device  10  according to the present embodiment includes a plurality of first wire groups G 11  through G 14  and a plurality of second wire groups G 21  through G 24 . 
     First wire group G 11  includes first wire  61  and first mark portion M 11  (i.e., first mark  41 ). First wire group G 12  includes first wire  62  and first mark portion M 12  (i.e., first mark  42 ). First wire group G 13  includes first wire  63  and first mark portion M 13  (i.e., first mark  43 ), First wire group G 14  includes first wire  64  and first mark portion M 14  (i.e., first mark  44 ). 
     In the top view of main surface  80   a  of substrate  80 , first wires  61  through  64  are disposed at positions overlapping first mark portions M 11  through M 14 , respectively. Stated differently, in the top view of main surface  80   a,  first wires  61  through  64  overlap first marks  41  through  44 , respectively. In the present embodiment, in the top view of main surface  80   a,  first marks  41  through  44  are disposed directly below first wires  61  through  64 , respectively, 
     This allows the plurality of first wires to be placed at appropriate positions by placing the first mark portions at appropriate placement positions for the respective first wires in the top view of main surface  80   a.  By inspecting whether the first wires overlap the respective first mark portions in the top view of main surface  80   a,  it is possible to determine whether the position of each of the plurality of first wires  61  through  64  is acceptable or not acceptable. 
     In the present embodiment, the plurality of first mark portions M 11  through M 14  are mutually different. Accordingly, the plurality of first wires  61  through  64  are arranged in accordance with the positions of the plurality of first mark portions that are mutually different. In addition, only one first wire overlaps each of the plurality of first mark portions. This reduces the possibility of a plurality of first wires being concentrated or contacting each other. 
     Second wire group G 21  includes second wire  71  and second mark portion M 21  (i.e., second marks  51  and  52 ). Second wire group G 22  includes second wire  72  and second mark portion M 22  (i.e., second marks  52  and  53 ). Second wire group G 23  includes second wire  73  and second mark portion M 23  (i.e., second marks  53  and  54 ). Second wire group G 24  includes second wire  74  and second mark portion M 24  (i.e., second marks  54  and  55 ). 
     In the top view of main surface  80   a  of substrate  80 , second wires  71  through  74  are disposed at positions overlapping second mark portions M 21  through M 24 , respectively. The positional relationship between each group of a second wire and two second marks in the case where each second mark portion includes two second marks will be described with reference to  FIG. 5 .  FIG. 5  is a schematic diagram illustrating the region indicated by second mark portion M 21  according to the present embodiment.  FIG. 5  illustrates second mark portion M 21  in the top view of main surface  80   a.    
     As illustrated in  FIG. 5 , in the top view of main surface  80   a , second mark portion M 21  includes two second marks  51  and  52  disposed spaced apart from each other and a line segment connecting the two second marks  51  and  52 . Stated differently, second mark portion M 21  includes each of the regions of second marks  51  and  52  and region MR that is a set of line segments connecting second mark  51  and second mark  52 . Stated further differently, second mark portion M 21  includes an envelope enclosing second mark  51  and second mark  52  and the region contained therein. The regions included in second mark portions M 22  through M 24  are also defined in the same manner as second mark portion M 21 . As illustrated in  FIG. 4 , in the present embodiment, in each second mark portion, the two second marks are spaced apart with a second wire between them. 
     By placing a second mark portion at an appropriate placement position of each second wire in the top view of main surface  80   a,  the plurality of second wires  71  through  74  can be placed at appropriate positions. By inspecting whether the second wires overlap the respective second mark portions in the top view of main surface  80   a , it is possible to determine whether the position of each of the plurality of second wires  71  through  74  is acceptable or not acceptable. 
     In the present embodiment, the plurality of second mark portions M 21  through M 24  are mutually different. Accordingly, the plurality of second wires  71  through  74  are arranged in accordance with the positions of the plurality of second mark portions that are mutually different. In addition, only one second wire overlaps each of the plurality of second mark portions. This reduces the possibility of a plurality of second wires being concentrated or contacting each other. 
     1-3. Stacked Structure of Semiconductor Laser Element 
     Next, the stacked structure of semiconductor laser element  20  according to the present embodiment will be described with reference to  FIG. 6 .  FIG. 6  is a schematic cross sectional view illustrating a configuration of semiconductor laser element  20  according to the present embodiment before being bonded to substrate  80 .  FIG. 6  illustrates a cross section taken perpendicular to the first direction (i.e., the lengthwise direction of the resonator) of semiconductor laser element  20  when viewed from the rear end face  20 R side. Accordingly, when semiconductor laser element  20  is bonded to substrate  80  as illustrated in  FIG. 3 , in  FIG. 6 , the right side of semiconductor laser element  20  is arranged on first side  81  side of substrate  80 , and the left side of semiconductor laser element  20  is arranged on second side  82  side of substrate  80 . 
     Semiconductor laser element  20  is, for example, a nitride semiconductor laser element, and before being bonded to substrate  80 , includes substrate  26 , first semiconductor layer  21 , active layer  22 , second semiconductor layer  23 , current blocking layer  240 , p-side ohmic electrode  250 , and electrodes  27  and  28 , as illustrated in  FIG. 6 . 
     Substrate  26  is, for example, a GaN substrate comprising GaN, In the present embodiment, a hexagonal n-type GaN substrate is used as substrate  26 . 
     First semiconductor layer  21  includes, for example, n-type cladding layer  211  comprising n-type AlGaN, and n-side guiding layer  212  comprising GaN formed on n-type cladding layer  211 . 
     Active layer  22  is an undoped quantum well active layer, for example, an active layer having a quantum well structure in which quantum well layers comprising InGaN and quantum barrier layers comprising InGaN are alternately stacked. 
     Second semiconductor layer  23  includes, for example, p-side guiding layer  231  comprising InGaN, p-type electron barrier layer (overflow inhibition layer)  232  formed on p-side guiding layer  231 , p-type cladding layer  233  comprising p-type AlGaN formed on p-type electron barrier layer  232 , p-type cladding layer  233  comprising p-type AlGaN formed on p-type electron barrier layer  232 , and p-type contact layer  234  comprising p-type GaN formed on p-type cladding layer  233 . 
     As illustrated in  FIG. 6 , semiconductor laser element  20  includes ridge portion  23 R extending in the lengthwise direction of the resonator (i.e., in the Y-axis direction). Ridge portion  23 R functions as a current injection region and an optical waveguide in semiconductor laser element  20 . As illustrated in  FIG. 6 , ridge portion  23 R is formed in second semiconductor layer  23 . 
     More specifically, ridge portion  23 R is formed by digging, into second semiconductor layer  23 , two openings  202  extending in the lengthwise direction of the resonator, Stated differently, ridge portion  23 R is sandwiched between two openings  202  formed in second semiconductor layer  23 , In the present embodiment, ridge portion  23 R is formed by digging into p-type cladding layer  233  and p-type contact layer  234 . 
     As illustrated in  FIG. 6 , except for the portion on ridge portion  23 R, the top of second semiconductor layer  23  (in the present embodiment, the top of p-type contact layer  234 ) is covered by current blocking layer  240  comprising SiO 2 . Stated differently, current blocking layer  240  is formed so as to include an opening on p-type contact layer  234 . 
     P-side ohmic electrode  250  and electrode  28  are formed above second semiconductor layer  23 . P-side ohmic electrode  250  is formed in the opening of current blocking layer  240 . Electrode  28  is formed on p-side ohmic electrode  250 . P-side ohmic electrode  250  comprises, for example, Pd and Pt, and electrode  28  comprises, for example, Au. 
     Electrode  27  is formed on the lower surface of substrate  26  (i.e., the surface opposite the surface on the electrode  28  side). Electrode  27  comprises, for example, Au. 
     As illustrated in  FIG. 6 , in semiconductor laser element  20  according to the present embodiment, the center line of ridge portion  23 R is at a position displaced in the second direction (the X-axis direction) from the widthwise center of semiconductor laser element  20 . Stated differently, ridge portion  23 R is disposed at a position offset in the second direction (the X-axis direction). 
     In the present embodiment, the position of ridge portion  23 R is offset in the negative direction of the X-axis (on the second side  82  side of substrate  80  when bonded to substrate  80  (see  FIG. 3 )). Accordingly, when each first bonding region to which a first wire is bonded is disposed in a region other than directly above ridge portion  23 R, the width of each first bonding region in the X-axis direction can be enlarged compared to when ridge portion  23 R is disposed in the center in the X-axis direction. Each first bonding region is offset in the positive direction of the X-axis (on the first side  81  side of substrate  80  when bonded to substrate  80  (see  FIG. 3 )) from the X-axis direction center of semiconductor laser element  20 . 
     Groove  262  is formed in a side surface portion of the X-axis direction end portion of semiconductor laser element  20 . Groove  262  is a groove for element separation that is used when semiconductor laser element  20  is diced. Groove  262  reaches from the semiconductor stacked body side to substrate  26 . 
     Grooves  263  and  264  that reach from second semiconductor layer  23  to first semiconductor layer  21  are formed in the semiconductor stacked body of semiconductor laser element  20 , Grooves  263  and  264  are guide grooves used when forming groove  262 . 
     Next, the configuration of semiconductor laser element  20  according to the present embodiment after being bonded to substrate  80  will be described with reference to  FIG. 7 .  FIG. 7  is a schematic cross sectional view illustrating a configuration of semiconductor laser element  20  according to the present embodiment after being bonded to substrate  80 .  FIG. 7  illustrates a cross section taken perpendicular to the first direction (i.e., the lengthwise direction of the resonator) of semiconductor laser element  20 . 
     As illustrated in  FIG. 7 , metal film  86  is formed on main surface  80   a  of substrate  80 . Semiconductor laser element  20  is bonded to metal film  86  on main surface  80   a  of substrate  80  by bonding member  88 . In the present embodiment, bonding member  88  includes Pt film  88   a  and solder film  88   b.  When bonding semiconductor laser element  20  to main surface  80   a  via bonding member  88 , electrode  27  comprising Au and the solder film comprising AuSn that are included in semiconductor laser element  20  are heated and melted. When these layers are cooled and solidify, they are united to form solder film  88   b,  which is a eutectic alloy. 
     1-4. Semiconductor Laser Device Manufacturing Method 
     Next, the manufacturing method of the semiconductor laser device  10  according to the present embodiment will be described with reference to  FIG. 8  through  FIG. 11 .  FIG. 8  through  FIG. 11  are schematic front views illustrating processes of the manufacturing method of semiconductor laser device  10  according to the present embodiment. 
     First, as illustrated in  FIG. 8 , stem  93  is prepared. Although not illustrated, stem  93  is erected on base  94 . Lead pins  91 ,  92  and  95  are also erected on base  94 . 
     Next, as illustrated in  FIG. 9 , substrate  80  is bonded to the top surface of stem  93  using bonding member  87 . Here, bonding member  88 A is disposed on main surface  80   a  of substrate  80 . Before semiconductor laser element  20  is bonded, bonding member  88 A includes two layers of a Pt film and a solder film comprising AuSn, which are stacked in order from the main surface  80   a  side. 
     Then, as illustrated in  FIG. 10 , semiconductor laser dement  20  is bonded to main surface  80   a  of substrate  80 . More specifically, semiconductor laser dement  20  is placed on main surface  80   a  so that, in the top view of main surface  80   a,  a straight line passing through and parallel to front end face  20 F of semiconductor laser element  20  overlaps third marks  31  and  32  formed on main surface  80   a  (see  FIG. 3 ). Thereafter, electrode  27  comprising Au of semiconductor laser element  20  and the solder film comprising AuSn of bonding member  88 A are melted by heating semiconductor laser element  20  and substrate  80  and subsequently cooled to produce solder film  88   b,  which is a eutectic alloy of bonding member  88  (see  FIG. 7 ), and bond substrate  80  and semiconductor laser element  20 . Here, semiconductor laser dement  20  is junction-up mounted. 
     Next, as illustrated in  FIG. 11 , lead pin  91  and semiconductor laser element  20  are connected by first wire  61 . Although not illustrated in  FIG. 11 , lead pin  91  and semiconductor laser element  20  are &amp;so connected by first wires  62  through  64 . More specifically, first wires  61  through  64  are connected to lead pin  91  and first bonding regions B 11  through B 14  of semiconductor laser dement  20 , respectively (see  FIG. 3 ). Lead pin  92  and main surface  80   a  of substrate  80  are connected by second wire  71 . Although not illustrated in  FIG. 11 , lead pin  92  and main surface  80   a  are also connected by second wires  72  through  74 . More specifically, second wires  71  through  74  are connected to lead pin  92  and second bonding regions B 21  through B 24  of main surface  80   a,  respectively (see  FIG. 3 ). Here, when connecting the wires to the bonding regions, the connection position of each wire may be adjusted with reference to its corresponding mark. For example, as illustrated in  FIG. 3 , first wires  61  through  64  connected to first bonding regions B 11  through B 14  connect to lead pin  91  through positions overlapping first mark portions M 11  through M 14 , specifically, directly above first marks  41  through  44 , in the top view of main surface  80   a  of substrate  80 . Second wires  71  through  74  connected to second bonding regions B 21  through B 24  connect to lead pin  92  through positions overlapping second mark portions M 21  through M 24 , specifically, directly above the separated regions connecting second marks  51  and  52 , second marks  52  and  53 , second marks  53  and  54 , and second marks  54  and  55 , in the top view of main surface  80   a  of substrate  80 . 
     Semiconductor laser device  10  is manufactured as described above. 
     Semiconductor laser device  10  may be provided with a cap. The cap is a cover that covers stem  93 , substrate  80 , semiconductor laser element  20 , and the portions of lead pin  91  and  92  adjacent to stem  93 . 
     1-5. Semiconductor Laser Device Inspection Method 
     Next, an inspection method of semiconductor laser device  10  according to the present embodiment will be described. 
     The manufactured semiconductor laser device  10  is inspected to see whether semiconductor laser element  20  is arranged so that a straight line passing through and parallel to front end face  20 F of semiconductor laser element  20  and the third marks overlap in the top view of main surface  80   a,  and inspection passes when the straight line and the third marks overlap. 
     The manufactured semiconductor laser device  10  is inspected to see whether the first wires are disposed overlapping the respective first mark portions and whether the second wires are disposed overlapping the respective second mark portions in the top view of main surface  80   a,  and inspection passes when all of the wires overlap their corresponding mark portions. 
     It is additionally possible to determine that inspection passes when each second bonding region is located on a line segment connecting third mark  32  and fourth mark  33 . 
     Embodiment 2 
     Next, the semiconductor laser device according to Embodiment 2 will be described. The semiconductor laser device according to the present embodiment differs from semiconductor laser device  10  according to Embodiment 1 mainly in regard to the configuration of the semiconductor laser element and the mounting configuration of the semiconductor laser element. Hereinafter, the semiconductor laser device according to the present embodiment will be described focusing on the differences from semiconductor laser device  10  of Embodiment 1. 
     2-1. Overall Configuration 
     First, the overall configuration of semiconductor laser device  110  according to the present embodiment will be described with reference to  FIG. 12  through  FIG. 14 .  FIG. 12  and  FIG. 13  are schematic front and top views, respectively, illustrating the overall configuration of semiconductor laser device  110  according to the present embodiment.  FIG. 14  is a schematic top view illustrating a configuration of semiconductor laser element  120  and substrate  180  according to the present embodiment. 
     Semiconductor laser device  110  is a device that emits a laser beam and, as illustrated in  FIG. 12  and  FIG. 13 , includes substrate  180  and semiconductor laser element  120 . As illustrated in  FIG. 13 , semiconductor laser device  110  further includes first wires  61  through  65 , second wires  71  through  75 , lead pins  91 ,  92 , and  95 , stem  93 , and base  94 . Although not illustrated in  FIG. 12  through  FIG. 14 , semiconductor laser device  110  may include a cap that covers the periphery of semiconductor laser element  120 , substrate  180 , and stem  93 . 
     As illustrated in  FIG. 14 , semiconductor laser element  120  is disposed on main surface  180   a  of substrate  180  and includes a resonator extending along a first direction among in-plane directions of main surface  180   a.  In the present embodiment, the resonator of semiconductor laser element  120  is formed with front end face  120 F and rear end face  120 R. Front end face  120 F is the end face on the end of semiconductor laser element  120  from which the laser beam is emitted, and has a lower reflectance to the laser beam than rear end face  1208 . Rear end face  120 R is a highly reflective end face that reflects the laser beam of semiconductor laser element  120 . The first direction is the direction in which the laser beam resonates, i.e., the direction in which the laser beam is emitted, and is parallel to the Y-axis direction in each figure. Front end face  120 F is disposed outside the outer edge of substrate  180  when substrate  180  is viewed from the top. 
     Electrode  129  is formed on the top surface of semiconductor laser element  120  (i.e., the surface opposite the surface bonded to substrate  180 ), The top surface of semiconductor laser element  120  includes first bonding regions B 11  through B 15  to which first wires  61  through  65  are respectively bonded. Semiconductor laser element  120  according to the present embodiment is junction-down mounted on main surface  180   a  of substrate  180 . In other words, semiconductor laser element  120  is mounted to main surface  180   a  on the semiconductor stacked body side of semiconductor laser element  120  rather than on the substrate side. In this case, unlike semiconductor laser device  10  according to Embodiment 1, the entire width (i.e., the X-axis direction dimension) of electrode  129  can be used as each first bonding region. 
     In the present embodiment, first bonding regions  1311  through B 15  are arranged in parallel in the first direction. The distances from front end face  120 F of semiconductor laser element  120  to the respective centers of first bonding regions B 11  through B 15  are 0.12 mm, 0.29 mm, 0.46 mm, 0.63 mm, and 0.80 mm, respectively. First bonding regions B 11  through B 15  are thus arranged spaced at equal intervals with a center-to-center distance of 0.17 mm. 
     Semiconductor laser element  120  is bonded to metal film  186  on main surface  180   a  of substrate  180  by bonding member  188 . The configuration of bonding member  188  is not particularly limited. In the present embodiment, bonding member  188  includes, in order from the metal film  186  side, a 0.32 μm thick Pt film and a 2.5 μm thick solder film comprising AuSn, The length of bonding member  188  in the second direction (i.e., the X-axis direction) is approximately 0.5 mm. 
     The size and structure of semiconductor laser element  120  are not particularly limited. In the present embodiment, the length of the resonator of semiconductor laser element  120  is 1200 μm, the width in second direction is 150 μm, and the thickness (the Z-axis direction dimension) is 85 μm. 
     The stacked structure of semiconductor laser element  120  will be described later. 
     Substrate  180  is a submount on which semiconductor laser element  120  is provided. Although the material included in substrate  180  is not particularly limited so long as the material has a high thermal conductivity, in the present embodiment, the material is SiC. 
     As illustrated in  FIG. 14 , substrate  180  includes main surface  180   a  on which metal film  186  is formed. Although the size and shape of substrate  180  are not particularly limited, in the present embodiment, substrate  180  has a rectangular shape with a length (i.e., a Y-axis direction dimension) of 1.3 mm, a width (i.e., an X-axis direction dimension) of 1.0 mm, and a thickness (i.e., a Z-axis direction dimension) of 0.20 mm. 
     The shape of main surface  180   a  is a rectangle including first side  181  extending along the first direction, second side  182  disposed on the opposite side of first side  181  across semiconductor laser element  120  and extending along the first direction, and third side  183  and fourth side  184  perpendicular to first side  181  and second side  182 . 
     Main surface  180   a  includes second bonding regions B 21  through B 25  to which second wires  71  through  75  are respectively bonded. Each second bonding region is disposed between semiconductor laser element  120  and second side  182  of main surface  180   a.  In the present embodiment, second bonding regions  321  through  325  are aligned spaced at equal intervals and parallel to the first direction. Second bonding regions  321  through  825  are spaced at 0.15 mm intervals. The distance from third side  183  of main surface  180   a  to the center of second bonding region B 21  is 0.13 mm, and the distance from fourth side  184  to the center of second bonding region B 25  is 0.57 mm. The distance from the second side of main surface  180   a  to each second bonding region is 0.10 mm. Metal film  186  is an electrically conductive film that is connected to one electrode of semiconductor laser element  120 . 
     Metal film  186  is not particularly limited as long as it is an electrically conductive film. In the present embodiment, metal film  186  includes, in order from main surface  180   a  of substrate  180 , a 0.1 μm thick Ti film, a 0.2 μm thick Pt film, and a 0.5 μm thick Au film. Metal film  186  is not formed in a 0.02 mm wide region at the edge of main surface  180   a.    
     First marks  141  through  146 , second marks  151  through  156 , and fourth marks  133  and  134  are formed in metal film  186 , Each mark is configured to be visible on main surface  180   a.  In the present embodiment, each mark is formed by removing a portion of metal film  186  from the Au film to the Ti film to expose main surface  180   a  from beneath metal film  186 . The configuration of each mark is not particularly limited as long as it is visible. For example, each mark may be formed by placing another film on metal film  186  that has a different reflectance than metal film  186 . 
     Each first mark is disposed between semiconductor laser element  120  and first side  181  of main surface  180   a.  In the present embodiment, each first mark has a square shape and each side of the square is inclined at 45 degrees relative to each side of main surface  180   a.  The length of each side of each first mark is approximately 30 μm to 100 μm, inclusive. 
     In the present embodiment, the distances from third side  183  of main surface  180   a  to the respective centers of first marks  141  through  146  are 0.05 mm, 0.20 mm, 0.35 mm, 0.50 mm, 0.65 mm, and 0.80 mm, respectively. The distance from fourth side  184  of main surface  180   a  to first mark  146  is 0.50 mm. The distance from first side  181  of main surface  180   a  to the respective centers of first marks  141 ,  143 , and  145  is 0.05 mm, and the distance from first side  181  to the respective centers of first marks  142 ,  144 , and  146  is 0.20 mm. That is, first marks  141  through  146  are arranged in a staggered arrangement (i.e., arranged in a zigzag arrangement) in the first direction. 
     Each second mark is disposed between semiconductor laser element  120  and second side  182  of main surface  180   a.  In the present embodiment, each second mark has a square shape and each side of the square is inclined at 45 degrees relative to each side of main surface  180   a.  The length of each side of each second mark is approximately 30 μm to 100 μm, inclusive. 
     In the present embodiment, the distances from third side  183  of main surface  180   a  to the respective centers of second marks  151  through  156  are 0.05 mm, 0.20 mm, 0.35 mm, 0.50 mm, 0.65 mm, and 0.80 mm, respectively. The distance from fourth side  184  of main surface  180   a  to second mark  156  is 0.50 mm. The distance from second side  182  of main surface  180   a  to the respective centers of second marks  151 ,  153 , and  155  is 0.05 mm, and the distance from second side  182  to the respective centers of second marks  152 ,  154 , and  156  is 0.20 mm. That is, second marks  151  through  156  are arranged in a staggered arrangement in the first direction. 
     Each fourth mark is a mark formed on main surface  180   a,  and in the top view of main surface  180   a,  each fourth mark overlaps with a straight line passing through and parallel to rear end face  120 R of semiconductor laser element  120 . This enables the alignment of rear end face  120 R of semiconductor laser element  120  based on the fourth marks. In the present embodiment, the distance from fourth side  184  of main surface  180   a  to the center of each fourth mark is 0.05 mm. The distance from first side  181  of main surface  180   a  to the center of fourth mark  133  and the distance from second side  182  to the center of fourth mark  134  are both 0.05 mm. Each fourth mark is thus disposed closer to the fourth side  184  of main surface  180   a  than any of the first and second marks are. 
     Although the shape of each fourth mark is not particularly limited, in the present embodiment, each fourth mark has a square shape and each side of the square is inclined at 45 degrees relative to each side of main surface  180   a.  The length of each side of each fourth mark is approximately 30 μm to 70 μm, inclusive. Although two fourth marks  133  and  134  are exemplified as being formed in the present embodiment, one fourth mark may be formed, and fourth marks  133  and  134  may not be formed. 
     As illustrated in  FIG. 14 , semiconductor laser device  110  according to the present embodiment includes a plurality of first mark portions M 11  through M 15  and a plurality of second mark portions M 21  through M 25 . First mark portion M 11  includes first marks  141  and  142 , first mark portion M 12  includes first marks  142  and  143 , first mark portion M 13  includes first marks  143  and  144 , first mark portion M 14  includes first marks  144  and  145 , and first mark portion M 15  includes first marks  145  and  146 . 
     Second mark portion M 21  includes second marks  151  and  152 , second mark portion M 22  includes second marks  152  and  153 , second mark portion M 23  includes second marks  153  and  154 , second mark portion M 24  includes second marks  154  and  155 , and second mark portion M 25  includes second marks  155  and  156 . 
     First mark portions M 11  through M 15  are mutually different. Stated differently, at least part of the one or more first marks included in each of first mark portions M 11  through M 15  is different, Second mark portions M 21  through M 25  are mutually different, Stated differently, at least part of the one or more second marks included in each of second mark portions M 21  through M 25  is different. 
     Although not illustrated in the drawings, a metal film is also formed on the main surface that is on the opposite side of main surface  180   a  of substrate  180 . In the present embodiment, a 0.1 pm thick Ti film, a 0.2 μm thick Pt film, and a 0.5 μm thick Au film are formed in the listed order from the substrate  180  side. 
     Substrate  180  is bonded to one surface of stem  93  by bonding member  187 . The configuration of bonding member  187  is not particularly limited. In the present embodiment, bonding member  187  includes a 4.0 μm thick solder film comprising AuSn. 
     As illustrated in  FIG. 13 , first wires  61  through  65  are electrically conductive wires for supplying current that connect lead pin  92  to semiconductor laser element  120 . As illustrated in  FIG. 14 , first wires  61  through  65  are bonded to first bonding regions B 11  through B 15  of the top surface of semiconductor laser element  120 , respectively. First wires  61  through  65  respectively include, at end portions on the semiconductor laser element  120  side, first ball portions  613  through  653  having a hemispherical shape. First ball portions  61 B through  65 B are bonded to the top surface of semiconductor laser element  120  at first bonding regions  311  through  315 , respectively. In the top view of main surface  180   a , each first wire intersects first side  181  of main surface  180   a.    
     The material and structure of each first wire is not particularly limited. In the present embodiment, each first wire is a 38 μm diameter wire comprising Au. The diameter of each first ball portion is approximately 85±15 μm. The diameter of each first wire may be greater than or equal to 15 μm and 50 μm or less. The diameter of each first ball portion may be greater than or equal to 30 μm and 100 μm or less. 
     As illustrated in  FIG. 13 , second wires  71  through  75  are wires for supplying current that connect lead pin  91  to main surface  80   a  of substrate  80 . As illustrated in  FIG. 14 , second wires  71  through  75  are bonded to second bonding regions B 21  through B 25  of main surface  180   a  of substrate  180 , respectively. Second wires  71  through  75  respectively include, at end portions on the main surface  180   a  side, second ball portions  71 B through  75 B having a hemispherical shape. Second ball portions  71 B through  75 B are bonded to main surface  180   a  at second bonding regions B 21  through B 25 , respectively. In the top view of main surface  180   a,  each second wire intersects second side  182  of main surface  180   a.    
     The material and structure of each second wire is not particularly limited. In the present embodiment, each second wire is a 38 μm diameter wire comprising Au. The diameter of each second ball portion is approximately 85±15 μm, The diameter of each second wire may be greater than or equal to 15 μm and 50 μm or less, The diameter of each second ball portion may be greater than or equal to 30 μm and 100 μm or less. 
     2-2. Configuration of First Wire Group and Second Wire Group 
     Just like semiconductor laser device  10  according to Embodiment 1, semiconductor laser device  110  according to the present embodiment also includes a plurality of first wire groups and a plurality of second wire groups. The configurations of each of the plurality of first wire groups and the plurality of second wire groups according to the present embodiment will be described below with reference to  FIG. 15 .  FIG. 15  is a schematic top view illustrating configurations of a plurality of first wire groups G 11  through G 15  and a plurality of second wire groups G 21  through G 25  of semiconductor laser device  110  according to the present embodiment. 
     As illustrated in  FIG. 15 , semiconductor laser device  110  according to the present embodiment includes a plurality of first wire groups G 11  through G 15  and a plurality of second wire groups G 21  through G 25 . 
     First wire group G 11  includes first wire  61  and first mark portion M 11  (i.e., first marks  141  and  142 ). First wire group G 12  includes first wire  62  and first mark portion M 12  (i.e., first marks  142  and  143 ). First wire group G 13  includes first wire  63  and first mark portion M 13  (i.e., first marks  143  and  144 ). First wire group G 14  includes first wire  64  and first mark portion M 14  (i.e., first marks  144  and  145 ). First wire group G 15  includes first wire  65  and first mark portion M 15  (i.e., first marks  145  and  146 ). 
     In the top view of main surface  180   a  of substrate  180 , first wires  61  through  65  are disposed at positions overlapping first mark portions M 11  through M 15 , respectively. In the present embodiment, each first mark portion includes, in the top view of main surface  180   a,  two first marks disposed spaced apart from each other and a line segment connecting the two first marks, and each first wire overlaps a line segment connecting two first marks. 
     By placing a first mark portion at an appropriate placement position of each first wire in the top view of main surface  180   a,  the plurality of first wires  61  through  65  can be placed at appropriate positions. By inspecting whether the first wires overlap the respective first mark portions in the top view of main surface  180   a , it is possible to determine whether the position of each of the plurality of first wires  61  through  65  is acceptable or not acceptable. 
     In the present embodiment, the plurality of first mark portions M 11  through M 15  are mutually different. Accordingly, the plurality of first wires  61  through  65  are arranged in accordance with the positions of the plurality of first mark portions that are mutually different. In addition, only one first wire overlaps each of the plurality of first mark portions. This reduces the possibility of a plurality of first wires being concentrated or contacting each other. 
     Second wire group G 21  includes second wire  71  and second mark portion M 21  (i.e., second marks  151  and  152 ), Second wire group G 22  includes second wire  72  and second mark portion M 22  (i.e., second marks  152  and  153 ). Second wire group G 23  includes second wire  73  and second mark portion M 23  (i.e., second marks  153  and  154 ). Second wire group G 24  includes second wire  74  and second mark portion M 24  (i.e., second marks  154  and  155 ). Second wire group G 25  includes second wire  75  and second mark portion M 25  (i.e., second marks  155  and  156 ). 
     In the top view of main surface  180   a,  second wires  71  through  75  are disposed at positions overlapping second mark portions M 21  through M 25 , respectively. In the present embodiment, each second mark portion includes, in the top view of main surface  180   a , two second marks disposed spaced apart from each other and a line segment connecting the two second marks, and second ball portion of each second wire overlaps a line segment connecting two second marks. Stated differently, in the top view of main surface  180   a , each second bonding region overlaps with a line segment connecting two second marks. 
     By placing a second mark portion at an appropriate placement position of each second wire in the top view of main surface  180   a,  the plurality of second wires  71  through  75  and the plurality of second ball portions  71 B through  75 B can be placed at appropriate positions. By inspecting whether the second wires overlap the respective second mark portions in the top view of main surface  180   a,  it is possible to determine whether the position of each of the plurality of second wires  71  through  75  is acceptable or not acceptable. 
     In the present embodiment, the plurality of second mark portions M 21  through M 25  are mutually different. Accordingly, the plurality of second wires  71  through  75  are arranged in accordance with the positions of the plurality of second mark portions that are mutually different. In addition, only one second wire overlaps each of the plurality of second mark portions. This reduces the possibility of a plurality of second wires being concentrated or contacting each other. 
     2-3. Electrode Structure of Semiconductor Laser Element 
     Next, the structure of electrode  129  of semiconductor laser element  120  according to the present embodiment will be described with reference to  FIG. 16 .  FIG. 16  is a schematic top view illustrating the structure of electrode  129  of semiconductor laser element  120  according to the present embodiment. 
     As illustrated in  FIG. 16 , semiconductor laser element  120  includes electrodes  129  disposed on the top surface. Electrode  129  includes a plurality of bonding portions Br 1  through Br 5  and one or more intermediate portions Ir 1  through Ir 4 . Each of the one or more intermediate portions Ir 1  through Ir 4  is disposed between two adjacent ones of the plurality of bonding portions Br 1  through Br 5 . More specifically, intermediate portion Ir 1  is disposed between the two adjacent bonding portions Br 1  and Br 2 , intermediate portion Ir 1  is disposed between the two adjacent bonding portions Br 2  and Br 3 , intermediate portion Ir 3  is disposed between the two adjacent bonding portions Br 3  and Br 4 , and intermediate portion Ir 4  is disposed between the two adjacent bonding portions Br 4  and Br 5 . The width in the second direction (i.e., the X-axis direction) perpendicular to the first direction of each of the plurality of bonding portions Br 1  through Br 5  is greater than the width in the second direction of each of the one or more intermediate portions Ir 1  through Ir 4 . 
     Making the width in the second direction at each bonding portion greater than the width in the second direction at each intermediate portion facilitates bonding of the wires to the respective bonding portions. In addition, by making the widths of the bonding portions and the intermediate portions in the second direction different, each bonding portion can be easily identified, which makes it easy to determine whether or not a wire is bonded to each bonding portion. 
     In the present embodiment, the widths of each bonding portion and each intermediate portion in the second direction are 120 μm and 80 μm, respectively. The lengths of each bonding portion and each intermediate portion in the first direction are 90 μm and 80 μm, respectively. 
     In addition, distance Df from bonding portion Br 1 , which is the bonding portion closest to front end face  120 F of semiconductor laser element  120  among the plurality of bonding portions Br 1  through Br 5 , to front end face  120 F is shorter than distance Dr from bonding portion Br 5 , which is the bonding portion closest to rear end face  120 R of semiconductor laser element  120  among the plurality of bonding portions Br 1  through Br 5 , to rear end face  120 R. 
     With this, bonding portion Br 1  can be positioned close to front end face  120 F, which is likely to consume the largest amount of current in semiconductor laser element  120 , which means that current can be efficiently supplied to the region close to front end face  120 F. In the present embodiment, distance Df is approximately 75 μm and distance Dr is approximately 355 μm. 
     In the present embodiment, among regions of the top surface that extends over length Lc of the resonator of semiconductor laser element  120 , the number of bonding portions disposed in a region close to front end face  120 F (that is, a region over distance Lc/2 from front end face  120 F) is greater than the number of bonding portions disposed in a region close to rear end face  120 R (that is, a region over distance Lc/2 from rear end face  120 R). Stated differently, among regions of the top surface of semiconductor laser element  120 , the surface area of the bonding portions disposed in a region dose to front end face  120 F is larger than the surface area of the bonding portions disposed in a region that is dose to rear end face  120 R. With this, more bonding portions can be disposed in the region dose to front end face  120 F, which is likely to consume the largest amount of current in semiconductor laser element  120 , which means that current can be efficiently supplied to the region close to front end face  120 F. 
     As illustrated in  FIG. 16 , in the present embodiment, electrode  129  includes, in a region between front end face  120 F and bonding portion Br 1 , an electrode portion having a narrower width in the second direction than bonding portion Br 1 . In contrast, in a region between rear end face  120 R and bonding portion Br 5 , electrode  129  includes a portion whose width in the second direction is narrower than bonding portion Br 1  and a portion whose width in the second direction is equivalent to bonding portion Br 5 . 
     In the present embodiment, semiconductor laser element  120  includes chip identification mark Lb disposed in a region, of electrode  129 , that is closer to rear end face  120 R than to front end face  120 F. Chip identification mark Lb is disposed in a region between rear end face  120 R and bonding portion Br 5  of electrode  129 , in a portion whose width in the second direction is equivalent to bonding portion Br 5 . 
     Such a chip identification mark Lb makes it possible to identify semiconductor laser element  120 . Moreover, the vicinity of rear end face  120 R of semiconductor laser element  120  consumes no more current than the vicinity of front end face  120 F. Therefore, placing the chip identification mark in the vicinity of rear end face  120 R reduces the effect on the output of semiconductor laser element  120  more so than when chip identification mark Lb is placed in the vicinity of front end face  120 F. 
     Chip identification mark Lb may depict characters indicating a model number or lot number or the like of the chip, or may depict a pattern such as a bar code. Chip identification mark Lb may be formed as a plate formed of a different material than electrode  129 , or may be formed directly on electrode  129  by a method such as imprinting. 
     2-4. Stacked Structure of Semiconductor Laser Element 
     Next, the stacked structure of semiconductor laser element  120  according to the present embodiment will be described with reference to  FIG. 17 .  FIG. 17  is a schematic cross section&amp; view illustrating a configuration of semiconductor laser element  120  according to the present embodiment before being bonded to substrate  180 .  FIG. 17  illustrates a cross section taken perpendicular to the first direction (i.e., the lengthwise direction of the resonator) of semiconductor laser element  120 . Since semiconductor laser element  120  is junction-down mounted, substrate  26  is shown on the upper side and the semiconductor stacked body is shown on the lower side. 
     Just like semiconductor laser element  20  according to Embodiment 1, semiconductor laser element  120  includes substrate  26 , first semiconductor layer  21 , active layer  22 , second semiconductor layer  23 , current blocking layer  240 , p-side ohmic electrode  250 , and electrodes  129  and  28 . 
     Semiconductor laser element  120  according to the present embodiment differs from semiconductor laser element  20  according to Embodiment 1 in regard to the configuration of electrode  129 , the arrangement of ridge portion  23 R, the shape of the side surfaces, and that grooves  263  and  264  are not formed. Hereinafter, only the differences between semiconductor laser element  120  and semiconductor laser element  20  according to Embodiment 1 will be described. 
     The structure of electrode  129  is as described above. Electrode  129  comprises, for example, Au. 
     In Embodiment 1, ridge portion  23 R is offset from the widthwise the X-axis direction) center, but in the present embodiment, ridge portion  23 R is disposed in the widthwise center. 
     In the present embodiment, groove  261  is formed in a side surface portion of the X-axis direction end portion of semiconductor laser element  120 . Groove  261  is a groove for element separation that is used when semiconductor laser element  120  is diced. Groove  261  is formed extending in the thickness direction of substrate  26  from the main surface of substrate  26  on which the semiconductor stacked body is not formed. 
     Next, the configuration of semiconductor laser element  120  according to the present embodiment after being bonded to substrate  180  will be described with reference to  FIG. 18 .  FIG. 18  is a schematic cross sectional view illustrating a configuration of semiconductor laser element  120  according to the present embodiment after being bonded to substrate  180 .  FIG. 18  illustrates a cross section taken perpendicular to the first direction (i.e., the lengthwise direction of the resonator) of semiconductor laser element  120 . 
     As illustrated in  FIG. 18 , metal film  186  is formed on main surface  180   a  of substrate  180 . Semiconductor laser element  120  is bonded to metal film  186  on main surface  180   a  of substrate  180  by bonding member  188 . In the present embodiment, bonding member  188  includes Pt film  188   a  and solder film  188   b.  When bonding semiconductor laser element  120  to main surface  180   a  via bonding member  188 , electrode  28  comprising Au and the solder film comprising AuSn that are included in semiconductor laser element  120  are heated and melted. When these layers are cooled and solidify, they are united to form solder film  188   b,  which is a eutectic alloy. 
     2-5. Semiconductor Laser Device Manufacturing Method 
     Next, the manufacturing method of the semiconductor laser device  110  according to the present embodiment will be described with reference to  FIG. 19  through  FIG. 23 .  FIG. 19  through  FIG. 23  are schematic front views illustrating processes of the manufacturing method of semiconductor laser device  110  according to the present embodiment. 
     First, as illustrated in  FIG. 19 , substrate  180  including bonding member  188 A disposed on main surface  180   a  is prepared. Before semiconductor laser element  120  is bonded, bonding member  188 A includes two layers of a Pt film and a solder film comprising AuSn, which are stacked in order from the main surface  180   a  side. 
     Then, as illustrated in  FIG. 20 , semiconductor laser element  120  is bonded to main surface  180   a  of substrate  180  using bonding member  188 . More specifically, semiconductor laser element  120  is placed on main surface  180   a  so that, in the top view of main surface  180   a,  a straight line passing through and parallel to rear end face  120 R of semiconductor laser element  120  overlaps fourth marks  133  and  134  (see  FIG. 14 ), Thereafter, electrode  28  comprising Au of semiconductor laser element  120  and the solder film comprising AuSn of bonding member  188 A are melted by heating semiconductor laser element  120  and substrate  180  and subsequently cooled to produce solder film  188   b,  which is a eutectic alloy of bonding member  188  (see  FIG. 18 ), and bond substrate  180  and semiconductor laser element  120 . Semiconductor laser element  120  is thus bonded to main surface  180   a.    
     Next, as illustrated in  FIG. 21 , stem  93  is prepared and bonding member  187  is placed on the top surface of stem  93 . Although not illustrated, stem  93  is erected on base  94 . Lead pins  91 ,  92  and  95  are also erected on base  94 . 
     Next, as illustrated in  FIG. 22 , substrate  180  is bonded to the top surface of stem  93  using bonding member  187 . 
     Next, as illustrated in  FIG. 23 , lead pin  92  and semiconductor laser element  120  are connected by first wire  61 , Although not illustrated in  FIG. 23 , lead pin  92  and semiconductor laser element  120  are also connected by first wires  62  through  65 . More specifically, first wires  61  through  65  are connected to lead pin  92  and first bonding regions B 11  through B 15  of semiconductor laser element  120 , respectively (see  FIG. 14 ). Lead pin  91  and main surface  180   a  of substrate  180  are connected by second wire  71 . Although not illustrated in  FIG. 23 , lead pin  91  and main surface  180   a  are also connected by second wires  72  through  75 . More specifically, second wires  71  through  75  are connected to lead pin  91  and second bonding regions B 21  through B 25  of main surface  180   a,  respectively (see  FIG. 14 ). Here, when connecting the wires to the bonding regions, the connection position of each wire may be adjusted with reference to its corresponding mark. For example, as illustrated in  FIG. 14 , in the top view of main surface  180   a  of substrate  180 , first wires  61  through  65  connected to first bonding regions B 11  through B 15  connect to lead pin  92  through positions overlapping first mark portions M 11  through M 15 , specifically, directly above the separated regions connecting first marks  141  and  142 , first marks  142  and  143 , first marks  143  and  144 , first marks  144  and  145 , and first marks  145  and  146 . Second wires  71  through  75  connect to substrate  180  by respectively connecting to second mark portions M 21  through M 25 , specifically, to second bonding regions B 21  through B 25  disposed in separated regions connecting second marks  151  and  152 , second marks  152  and  153 , second marks  153  and  154 , second marks  154  and  155 , and second marks  155  and  156 , and the other ends of second wires  71  through  75  are connected to lead pin  91 . 
     Semiconductor laser device  110  is manufactured as described above. 
     Just like semiconductor laser device  10  according to Embodiment 1, semiconductor laser device  110  may be provided with a cap. 
     2-6. Semiconductor Laser Device Inspection Method 
     The manufactured semiconductor laser device  110  is inspected to see whether a straight line passing through and parallel to rear end face  120 R of semiconductor laser element  120  overlaps fourth marks  133  and  134  in the top view of main surface  180   a,  and inspection passes when the straight line overlaps the fourth marks. 
     The manufactured semiconductor laser device  110  is inspected to see whether the first wires are disposed overlapping the respective first mark portions in the top view of main surface  180   a , and inspection passes when all of the first wires overlap their corresponding first mark portions. Whether the second wires are bonded to substrate  180  in the respective second bonding regions disposed overlapping the respective second mark portions in the top view of main surface  180   a  is also inspected, and inspection passes when all of the second wires are bonded to substrate  180  in their corresponding second bonding regions disposed overlapping the respective second mark portions. 
     Embodiment 3 
     Next, the semiconductor laser device according to Embodiment 3 will be described. The semiconductor laser device according to the present embodiment differs from semiconductor laser device  110  according to Embodiment 2 mainly in regard to the configuration of the second wire group and the arrangement of semiconductor laser element  120 . Hereinafter, the semiconductor laser device according to the present embodiment will be described focusing on the differences from semiconductor laser device  110  of Embodiment 2. 
     3-1. Overall Configuration 
     First, the overall configuration of the semiconductor laser device according to the present embodiment will be described with reference to  FIG. 24  and  FIG. 25 .  FIG. 24  is a schematic top view illustrating a configuration of semiconductor laser device  310  according to the present embodiment.  FIG. 25  is a schematic top view illustrating a plurality of first mark portions M 11  through M 15  and a plurality of second mark portions M 20  through M 29  of semiconductor laser device  310  according to the present embodiment. 
     As illustrated in  FIG. 24  and  FIG. 25 , semiconductor laser device  310  according to the present embodiment includes substrate  380 , semiconductor laser element  120 , bonding member  188 , first wires  61  through  65 , and second wires  70  through  79 . 
     Semiconductor laser device  310  may further include lead pins  91 ,  92 , and  95 , stem  93 , and base  94 , just like in semiconductor laser device  110  according to Embodiment 2. 
     Substrate  380  is a submount on which semiconductor laser element  120  is provided. As illustrated in  FIG. 24 , substrate  380  includes main surface  380   a  on which metal film  386  is formed. Substrate  380  according to the present embodiment differs from substrate  180  according to Embodiment 2 in regard to the configuration of metal film  386 , and is the same in regard to other configurations. 
     The shape of main surface  380   a  is a rectangle including first side  381  extending along the first direction, second side  382  disposed on the opposite side of first side  381  across semiconductor laser element  120  and extending along the first direction, and third side  383  and fourth side  384  perpendicular to first side  381  and second side  382 . Main surface  380   a  includes second bonding regions B 20  through B 29  to which second wires  70  through  79  are respectively bonded. Each second bonding region is disposed between semiconductor laser element  120  and second side  382  of main surface  380   a.  More specifically, each second bonding region is disposed between bonding member  188  and second side  382  of main surface  380   a.  Bonding member  188  is a member that bonds main surface  380   a  of substrate  380  and semiconductor laser element  120 . In the present embodiment, bonding member  188  bonds metal film  386  formed on main surface  380   a  and semiconductor laser element  120 . Bonding member  188  has a rectangular shape extending in the first direction in the top view of main surface  380   a.  Bonding member  188  is formed, for example, of the same material as bonding member  188  according to Embodiment 2. 
     In the present embodiment, the distance from each second bonding region to bonding member  188  is shorter than the distance from each second bonding region to second side  382 . This allows each second bonding region to be brought closer to semiconductor laser element  120 , which is a heat source, so heat can be efficiently dissipated via each second wire. Bringing each second bonding region closer to semiconductor laser element  120  also reduces the resistance component between each second bonding region and semiconductor laser element  120 . Accordingly, the power conversion efficiency of semiconductor laser device  310  can be increased. 
     In the present embodiment, second bonding regions B 20  through B 29  are arranged in a staggered arrangement along the first direction. More specifically, second bonding regions B 20 , B 22 , B 24 , B 26 , and B 28  are aligned spaced at equal intervals and parallel to the first direction in the listed order. Second bonding regions B 21 , B 23 , B 25 , B 27 , and B 29  are aligned spaced at equal intervals and parallel to the first direction in the listed order and are disposed between second bonding regions B 20 , B 22 , B 24 , B 26 , and B 28  on one side and second side B 82  of main surface  380   a  on the other side. The positions of second bonding regions B 20  through B 29  in the first direction are mutually different. The position of second bonding region B 21  in the first direction is between the position of second bonding region B 20  in the first direction and the position of second bonding region B 22  in the first direction. The position of second bonding region B 23  in the first direction is between the position of second bonding region B 22  in the first direction and the position of second bonding region B 24  in the first direction. The position of second bonding region B 25  in the first direction is between the position of second bonding region B 24  in the first direction and the position of second bonding region B 26  in the first direction. The position of second bonding region B 27  in the first direction is between the position of second bonding region B 26  in the first direction and the position of second bonding region B 28  in the first direction. Second bonding region B 29  is disposed between second bonding region B 28  and fourth side B 84  of main surface  380   a.    
     By arranging second bonding regions B 20  through B 29  in this manner, more second bonding regions can be provided on main surface  380   a  while inhibiting each second bonding region (i.e., each second wire) from interfering with each other. Accordingly, more heat can be dissipated from substrate B 80  through the second bonding regions and the second wires, thereby increasing the heat dissipation efficiency of semiconductor laser device  310 . In the present embodiment, for example, the number and surface area of the second bonding regions can be doubled compared to when second bonding regions B 21  through B 25  are aligned in a single row, as they are in semiconductor laser device  110  according to Embodiment 2. Accordingly, the heat dissipation efficiency of semiconductor laser device  310  can be increased to approximately twice the heat dissipation efficiency of semiconductor laser device  110  according to Embodiment 2. 
     Second bonding regions B 20 , B 22 , B 24 , B 26 , and B 28  are spaced at 0.15 mm intervals. Second bonding regions B 21 , B 23 , B 25 , B 27 , and B 29  are spaced at 0.15 mm intervals. The distances from third side  383  of main surface  380   a  to the respective centers of second bonding regions  320  and  321  are 0.13 mm and 0.205 mm (=0.13+0.15/2), respectively, and the distances from fourth side  384  of main surface  380   a  to the respective centers of second bonding regions B 28  and B 29  are 0.57 mm and 0.495 mm. The distance from second side  382  of main surface  380   a  to the respective centers of second bonding regions B 20 , B 22 , B 24 , B 26 , and B 28  is 0.30 mm, and the distance from second side B 82  to the respective centers of second bonding regions B 21 , B 23 , B 25 , B 27 , and B 29  is 0.18 mm. 
     Metal film  386  is an electrically conductive film that is connected to one electrode of semiconductor laser element  120 . Metal film  386  is not particularly limited as long as it is an electrically conductive film. In the present embodiment, metal film  386  includes, in order from main surface  380   a  of substrate  380 , a 0.1 μm thick Ti film, a 0.2 μm thick Pt film, and a 0.5 μm thick Au film. Metal film  386  is not formed in a 0.02 mm wide region at the edge of main surface  380   a.    
     First marks  341  through  346 , second marks  350  through  361 , and fifth marks  331 ,  333 ,  334 , and  335  are formed in metal film  386 . Each mark is configured to be visible on main surface  380   a.    
     Each first mark  341  through  346  is disposed between semiconductor laser element  120  and first side  381  of main surface  380   a.  More specifically, each first mark is disposed between the edge of metal film  386  on the first side  381  side and bonding member  188 . First marks  341  through  346  are aligned spaced at equal intervals and parallel to the first direction. In the present embodiment, first marks  341  through  346  are spaced at 0.17 mm intervals. First mark  341  has the shape of a cross, and each of first marks  342  through  346  has a square shape. Each side of the square shaped first marks  342  through  346  is inclined at 45 degrees relative to each side of main surface  380   a.    
     Each second mark is disposed between semiconductor laser element  120  and second side  382  of main surface  380   a.  More specifically, each second mark is disposed between the edge of metal film  386  on the second side  382  side and bonding member  188 . Second marks  350  through  361  are arranged in a staggered arrangement along the first direction. More specifically, second marks  350 ,  352 ,  354 ,  356 ,  358 , and  360  are aligned spaced at equal intervals and parallel to the first direction in the listed order. Second marks  351 ,  353 ,  355 ,  357 ,  359 , and  361  are aligned spaced at equal intervals and parallel to the first direction in the listed order and are disposed between second marks  350 ,  352 ,  354 ,  356 ,  358 , and  360  on one side and second side  382  on the other side. The positions of second marks  350  through  361  in the first direction are mutually different. For example, the position of second mark  351  in the first direction is between the position of second mark  350  in the first direction and the position of second mark  352  in the first direction. Second marks  350 ,  352 ,  354 ,  356 ,  358 , and  360  are spaced at 0.15 mm intervals. Second marks  351 ,  353 ,  355 ,  357 ,  359 , and  361  are arranged at 0.15 mm intervals. The distance from each second mark to bonding member  188  is shorter than the distance from each second mark to the second side. 
     In the present embodiment, second bonding region B 20  is disposed between second marks  350  and  352 . Similarly, second bonding region B 21  is disposed between second marks  351  and  353 , second bonding region B 22  is disposed between second marks  352  and  354 , second bonding region B 23  is disposed between second marks  353  and  355 , second bonding region B 24  is disposed between second marks  354  and  356 , second bonding region B 25  is disposed between second marks  355  and  357 , second bonding region B 26  is disposed between second marks  356  and  358 , second bonding region B 27  is disposed between second marks  357  and  359 , second bonding region B 28  is disposed between second marks  358  and  360 , and second bonding region B 29  is disposed between second marks  359  and  361 . 
     In the present embodiment, second marks  350  through  361  have a square shape. Each side of the square shaped second marks  350  through  361  is parallel or perpendicular to each side of main surface  380   a.    
     Fifth marks  331 ,  333 , and  334  are marks for indicating the positions of vertices of main surface  380   a.  Fifth marks  331 ,  333 , and  334  are arranged in the vicinity of vertices of main surface  380   a.  Fifth mark  331  is disposed in the vicinity of the vertex corresponding to the intersection of second side  382  and third side  383  of main surface  380   a.  Fifth mark  333  is disposed in the vicinity of the vertex corresponding to the intersection of first side  381  and fourth side  384  of main surface  380   a.  Fifth mark  334  is disposed in the vicinity of the vertex corresponding to the intersection of second side  382  and fourth side  384  of main surface  380   a.  First mark  341  may be used as a mark indicating the position of the vertex corresponding to the intersection of first side  381  and third side  383  of main surface  380   a . Fifth mark  335  is a mark disposed between second mark  351  and third side  383  of main surface  380   a,  and indicates the positions of second marks  351 ,  353 ,  355 ,  357 ,  359 , and  361  in the second direction. The position of fifth mark  335  in the second direction is equal to the positions of second marks  351 ,  353 ,  355 ,  357 ,  359  and  361  in the second direction. 
     In the present embodiment, each of fifth marks  331 ,  333 , and  334  has the shape of a cross, and fifth mark  335  has a square shape. Each side of the square shaped fifth mark  335  is inclined at 45 degrees relative to each side of main surface  380   a.    
     Just like in Embodiment 2, in the present embodiment as well, each mark is formed by removing a portion of metal film  386  from the Au film to the Ti film to expose main surface  380   a  from beneath metal film  386 . The configuration of each mark is not particularly limited as long as it is visible. 
     As illustrated in  FIG. 25 , semiconductor laser device  310  according to the present embodiment includes a plurality of first mark portions M 11  through M 15  and a plurality of second mark portions M 20  through M 29 . First mark portion M 11  includes first marks  341  and  342 , first mark portion M 12  includes first marks  342  and  343 , first mark portion M 13  includes first marks  343  and  344 , first mark portion M 14  includes first marks  344  and  345 , and first mark portion M 15  includes first marks  345  and  346 . 
     Second mark portion M 20  includes second marks  350  and  352 , second mark portion M 21  includes second marks  351  and  353 , second mark portion M 22  includes second marks  352  and  354 , second mark portion M 23  includes second marks  353  and  355 , second mark portion M 24  includes second marks  354  and  356 , second mark portion M 25  includes second marks  355  and  357 , second mark portion M 26  includes second marks  356  and  358 , second mark portion M 27  includes second marks  357  and  359 , second mark portion M 28  includes second marks  358  and  360 , second mark portion M 29  includes second marks  359  and  361 . 
     First mark portions M 11  through M 15  are mutually different. Stated differently, at least part of the one or more first marks included in each of first mark portions M 11  through M 15  is different. 
     Second mark portions M 20  through M 29  are mutually different. Stated differently, at least part of the one or more second marks included in each of second mark portions M 20  through M 29  is different. 
     Semiconductor laser element  120  is disposed on main surface  380   a  of substrate  380  just like as in Embodiment 2. As illustrated in  FIG. 24 , in the present embodiment, the distance from semiconductor laser element  120  to first side  381  is shorter than the distance from semiconductor laser element  120  to second side  382 , As a result, the surface area of the region of main surface  380   a  from semiconductor laser element  120  to second side  382  is larger than when the distances from semiconductor laser element  120  to first side  381  and second side  382  are equal. Accordingly, it is possible to dispose more second wires (i.e., second bonding regions) in the region of main surface  380   a  from semiconductor laser element  120  to second side  382 . Similar to the arrangement of semiconductor laser element  120 , the distance from bonding member  188  to first side  381  is shorter than the distance from bonding member  188  to second side  382 . Semiconductor laser element  120  is disposed at approximately the center in the second direction of bonding member  188 . Just like in Embodiment 2, first bonding regions  311  through  315  are disposed on the top surface of semiconductor laser element  120 . 
     The plurality of first wires  61  through  65  according to the present embodiment have the same configuration as the plurality of first wires  61  through  65  according to Embodiment 2, respectively. As illustrated in  FIG. 24 , the plurality of first wires  61  through  65  are bonded to first bonding regions B 11  through B 15  of the top surface of semiconductor laser element  120 , respectively. 
     Second wires  70  through  79  are wires for supplying current that connect to main surface  380   a  of substrate  380 . As illustrated in  FIG. 24 , second wires  70  through  79  are bonded to second bonding regions B 20  through B 29  of main surface  380   a  of substrate  380 , respectively. Second wires  70  through  79  respectively include, at end portions on the main surface  380   a  side, second ball portions  703  through  793  having a hemispherical shape. Second ball portions  703  through  793  are bonded to main surface  380   a  at second bonding regions B 20  through B 29 , respectively. In the top view of main surface  380   a,  each second wire intersects second side  382  of main surface  380   a.    
     The material and structure of each second wire is not particularly limited. In the present embodiment, the material and structure of each second wire is the same as the material and structure of each second wire according to Embodiment 2, In the present embodiment, the number of second wires can be increased compared to Embodiment 2, and thus the current flowing per second wire can be reduced. As a result, the amount of heat generated in each second wire can be reduced, whereby melting of each second wire can be inhibited and conduction of the heat generated in each second wire to substrate  380  can be inhibited. Moreover, since the increase in temperature of each second wire can be inhibited, heat dissipation from substrate  380  through each second wire can be promoted. 
     For example, if the diameter of each second wire is 38 μm and the length of each second wire is 2 mm, the fusing current (i.e., the minimum current at which the second wire melts) is approximately 4.86 A. In this case, the rated current of each second wire is set, for example, to 2.43 A, which is approximately half of the fusing current. In semiconductor laser device  110  according to Embodiment 2, when a wire of the above dimensions is used for each of the five second wires, the rated current supplied to semiconductor laser element  120  is 12.2 A. However, in the present embodiment, in order to supply a current of 12.2 A to semiconductor laser element  120 , the current supplied to each of the ten second wires can be reduced to 1.22 A, Accordingly, in the present embodiment, when a wire of the above dimensions is used for each second wire, a current (1.22 A or lower) sufficiently lower than the fusing current is supplied to each second wire, whereby heat generation in each second wire can be reduced and melting of each second wire can be inhibited. In the present embodiment, it is also possible to supply a maximum current of 24.3 A to semiconductor laser element  120  by supplying a rated current of 2.43 A to each second wire. 
     The dimensions of each second wire are not limited to the above dimensions, The dimensions of each second wire may be any dimensions as long as they are sufficient to be applicable to semiconductor laser device  310 ; for example, each second wire may have a diameter of 25 μm and a length of 1.72 mm. In this case, since the fusing current of each second wire is approximately 2.43 A, the rated current is approximately 1.22 A. 
     3-2. Configuration of First Wire Group and Second Wire Group 
     Next, the first wire group and the second wire group according to the present embodiment will be described with reference to  FIG. 26 .  FIG. 26  is a schematic top view illustrating configurations of a plurality of first wire groups G 11  through G 15  and a plurality of second wire groups G 20  through G 29  according to the present embodiment. 
     As illustrated in  FIG. 26 , semiconductor laser device  310  according to the present embodiment includes a plurality of first wire groups G 11  through G 15  and a plurality of second wire groups G 20  through G 29 . The number of the plurality of second wire groups G 20  to G 29  is greater than the number of the plurality of first wire groups G 11  to G 15 . This allows the current supplied to each second wire to be reduced. 
     Each first wire group includes one or more first marks. In the present embodiment, first wire group G 11  includes first wire  61  and first mark portion M 11  (i.e., first marks  341  and  342 ). First wire group G 12  includes first wire  62  and first mark portion M 12  (i.e., first marks  342  and  343 ). First wire group G 13  includes first wire  63  and first mark portion M 13  (i.e., first marks  343  and  344 ), First wire group G 14  includes first wire  64  and first mark portion M 14  (i.e., first marks  344  and  345 ). First wire group G 15  includes first wire  65  and first mark portion M 15  (i.e., first marks  345  and  346 ). 
     In the top view of main surface  380   a  of substrate  380 , first wires  61  through  65  are disposed at positions overlapping first mark portions M 11  through M 15 , respectively. In the present embodiment, each first mark portion includes, in the top view of main surface  380   a,  two first marks disposed spaced apart from each other and a line segment connecting the two first marks, and each first wire overlaps a line segment connecting two first marks. 
     By placing a first mark portion at an appropriate placement position of each first wire in the top view of main surface  380   a,  the plurality of first wires  61  through  65  can be placed at appropriate positions. By inspecting whether the first wires overlap the respective first mark portions in the top view of main surface  380   a , it is possible to determine whether the position of each of the plurality of first wires  61  through  65  is acceptable or not acceptable. 
     In the present embodiment, the plurality of first mark portions M 11  through M 15  are mutually different. Accordingly, the plurality of first wires  61  through  65  are arranged in accordance with the positions of the plurality of first mark portions that are mutually different. In addition, only one first wire overlaps each of the plurality of first mark portions. This reduces the possibility of a plurality of first wires being concentrated or contacting each other. 
     Each second wire group includes one or more second marks. Second wire group G 20  includes second wire  70  and second mark portion M 20  (i.e., second marks  350  and  352 ). Second wire group G 21  includes second wire  71  and second mark portion M 21  (i.e., second marks  351  and  353 ). Second wire group G 22  includes second wire  72  and second mark portion M 22  (i.e., second marks  352  and  354 ). Second wire group G 23  includes second wire  73  and second mark portion M 23  (i.e., second marks  353  and  355 ). Second wire group G 24  includes second wire  74  and second mark portion M 24  (i.e., second marks  354  and  356 ). Second wire group G 25  includes second wire  75  and second mark portion M 25  (i.e., second marks  355  and  357 ). Second wire group G 26  includes second wire  76  and second mark portion M 26  (i.e., second marks  356  and  358 ). Second wire group G 27  includes second wire  77  and second mark portion M 27  (i.e., second marks  357  and  359 ). Second wire group G 28  includes second wire  78  and second mark portion M 28  (i.e., second marks  358  and  360 ). Second wire group G 29  includes second wire  79  and second mark portion M 29  (i.e., second marks  359  and  361 ). 
     In the top view of main surface  380   a,  second wires  70  through  79  are disposed at positions overlapping second mark portions M 20  through M 29 , respectively. In the present embodiment, each second mark portion includes, in the top view of main surface  380   a , two second marks disposed spaced apart from each other and a line segment connecting the two second marks, and second ball portion of each second wire overlaps a line segment connecting two second marks. Stated differently, in the top view of main surface  380   a , each second bonding region overlaps with a line segment connecting two second marks. 
     By placing a second mark portion at an appropriate placement position of each second wire in the top view of main surface  380   a,  the plurality of second wires  70  through  79  and the plurality of second ball portions  70 B through  79 B can be placed at appropriate positions. By inspecting whether the second wires overlap the respective second mark portions in the top view of main surface  380   a,  it is possible to determine whether the position of each of the plurality of second wires  70  through  79  is acceptable or not acceptable. 
     In the present embodiment, the plurality of second mark portions M 20  through M 29  are mutually different. Accordingly, the plurality of second wires  70  through  79  are arranged in accordance with the positions of the plurality of second mark portions that are mutually different. This reduces the possibility of a plurality of second wires being concentrated or contacting each other. 
     Embodiment 4 
     Next, the semiconductor laser device according to Embodiment 4 will be described. The semiconductor laser device according to the present embodiment differs from semiconductor laser device  310  according to Embodiment 3 mainly in regard to the configuration of the first wire group and the configuration of the semiconductor laser element. Hereinafter, the semiconductor laser device according to the present embodiment will be described focusing on the differences from semiconductor laser device  310  of Embodiment 3. 
     4-1. Overall Configuration 
     First, the overall configuration of the semiconductor laser device according to the present embodiment will be described with reference to  FIG. 27  and  FIG. 28 .  FIG. 27  is a schematic top view illustrating a configuration of semiconductor laser device  410  according to the present embodiment.  FIG. 28  is a schematic top view illustrating a plurality of first mark portions M 10  through M 19  and a plurality of second mark portions M 20  through M 29  of semiconductor laser device  410  according to the present embodiment. 
     As illustrated in  FIG. 27  and  FIG. 28 , semiconductor laser device  410  according to the present embodiment includes substrate  480 , semiconductor laser element  420 , bonding member  188 , first wires  60  through  69 , and second wires  70  through  79 . Semiconductor laser device  410  may further include lead pins  91 ,  92 , and  95 , stem  93 , and base  94 , just like in semiconductor laser device  110  according to Embodiment 2. 
     Substrate  480  is a submount on which semiconductor laser element  420  is provided. As illustrated in  FIG. 27 , substrate  480  includes main surface  480   a  on which metal film  486  is formed. Substrate  480  according to the present embodiment differs from substrate  380  according to Embodiment 3 in regard to the configuration of metal film  486 , and is the same in regard to other configurations. 
     The shape of main surface  480   a  is a rectangle including first side  481  extending along the first direction, second side  482  disposed on the opposite side of first side  481  across semiconductor laser element  420  and extending along the first direction, and third side  483  and fourth side  484  perpendicular to first side  481  and second side  482 . Main surface  480   a  includes second bonding regions B 20  through B 29  to which second wires  70  through  79  are respectively bonded. Each second bonding region is disposed between semiconductor laser element  420  and second side  482  of main surface  480   a.  More specifically, each second bonding region is disposed between bonding member  188  and second side  482  of main surface  480   a.  Bonding member  188  is a member that bonds main surface  480   a  of substrate  480  and semiconductor laser element  420 . In the present embodiment, bonding member  188  bonds metal film  486  formed on main surface  480   a  and semiconductor laser element  420 . Bonding member  188  has a rectangular shape extending in the first direction in the top view of main surface  480   a.  Bonding member  188  is formed, for example, of the same material as bonding member  188  according to Embodiment 2 and Embodiment 3. Second bonding regions B 20  through B 29  according to the present embodiment have the same configuration as second bonding regions B 20  through B 29  according to Embodiment 3. 
     Metal film  486  is an electrically conductive film that is connected to one electrode of semiconductor laser element  420 . Metal film  486  is not particularly limited as long as it is an electrically conductive film. In the present embodiment, metal film  486  includes, in order from main surface  480   a  of substrate  480 , a 0.1 μm thick Ti film, a 0.2 μm thick Pt film, and a 0.5 μm thick Au film. Metal film  386  is not formed in a 0.02 mm wide region at the edge of main surface  380   a.    
     First marks  440  through  449 , second marks  350  through  361 , and fifth marks  431 ,  432 ,  433 ,  434 , and  335  are formed on metal film  486 . Each mark is configured to be visible on main surface  480   a.    
     Each first mark is disposed between semiconductor laser element  420  and first side  481  of main surface  480   a.  The shape and dimensions of each first mark according to the present embodiment are the same as for each first mark according to Embodiment 1. Each first mark has a quadrangular shape and is in contact with the outer edge on the first side  481  side of main surface  480   a  of metal film  486 . Stated differently, each first mark is a notch formed inwardly from the first side  481  side end portion of metal film  486 . 
     In the top view of main surface  480   a,  first marks  440  through  449  are disposed directly below first wires  60  through  69 , respectively. In the present embodiment, the distance from third side  483  of main surface  480   a  to the center of each first mark  440  in the first direction is 0.12 mm. First marks  440  through  449  are aligned spaced at equal intervals with a center-to-center distance of 0.085 mm. 
     Each second mark is disposed between semiconductor laser element  420  and second side  482  of main surface  480   a.  More specifically, each second mark is disposed between the edge of metal film  486  on the second side  482  side and bonding member  188 . Second marks  350  through  361  are arranged in same manner as second marks  350  through  361  according to Embodiment 3. 
     Fifth marks  431  through  434  are marks for indicating the position of each vertex of main surface  480   a.  Fifth marks  431  through  434  are arranged in the vicinity of respective vertices of main surface  480   a.  Fifth mark  431  is disposed in the vicinity of the vertex corresponding to the intersection of second side  482  and third side  483  of main surface  480   a.  Fifth mark  432  is disposed in the vicinity of the vertex corresponding to the intersection of first side  481  and third side  483  of main surface  480   a.  Fifth mark  433  is disposed in the vicinity of the vertex corresponding to the intersection of first side  481  and fourth side  484  of main surface  480   a . Fifth mark  434  is disposed in the vicinity of the vertex corresponding to the intersection of second side  482  and fourth side  384  of main surface  480   a.  Fifth mark  335  is a mark disposed between second mark  351  and third side  483  of main surface  480   a,  and indicates the positions of second marks  351 ,  353 ,  355 ,  357 ,  359 , and  361  in the second direction. The position of fifth mark  335  in the second direction is equal to the positions of second marks  351 ,  353 ,  355 ,  357 ,  359  and  361  in the second direction. 
     In the present embodiment, each of fifth marks  431  through  434  has the shape of a cross, and fifth mark  335  has a square shape, Each side of the square shaped fifth mark  335  is inclined at 45 degrees relative to each side of main surface  480   a.    
     Just like in Embodiment 2, in the present embodiment as well, each mark is formed by removing a portion of metal film  486  from the Au film to the Ti film to expose main surface  480   a  from beneath metal film  486 . The configuration of each mark is not particularly limited as long as it is visible. 
     As illustrated in  FIG. 28 , semiconductor laser device  410  according to the present embodiment includes a plurality of first mark portions M 10  through M 19  and a plurality of second mark portions M 20  through M 29 . First mark portions M 10  through M 19  include first marks  440  through  449 , respectively. 
     The configuration of second mark portions M 20  through M 29  is the same as the configuration of second mark portions M 20  through M 29  according to Embodiment 3. 
     The first mark portions are mutually different. Stated differently, the first marks included in the first mark portions, which is one first mark per first mark portion, are mutually different. Second mark portions M 20  through M 29  are mutually different. 
     As illustrated in FIG,  27  and FIG,  28 , semiconductor laser element  420  according to the present embodiment is disposed on main surface  480   a  of substrate  480  and includes a resonator extending along a first direction among in-plane directions of main surface  480   a.  In the present embodiment, the resonator of semiconductor laser element  420  is formed with front end face  420 F and rear end face  420 R. Front end face  420 F is the end face on the end of semiconductor laser element  420  from which the laser beam is emitted, and has a lower reflectance to the laser beam than rear end face  420 R. Rear end face  420 R is a highly reflective end face that reflects the laser beam of semiconductor laser element  420 . The first direction is the direction in which the laser beam resonates, i.e., the direction in which the laser beam is emitted, and is parallel to the Y-axis direction in each figure. Front end face  420 F is disposed outside the outer edge of substrate  480  when substrate  480  is viewed from the top. 
     Electrode  429  is formed on the top surface of semiconductor laser element  420  (i.e., the surface opposite the surface bonded to substrate  480 ). In the present embodiment, electrode  429  has the shape of a rectangle in the top view of main surface  480   a  of substrate  480 . The top surface of semiconductor laser element  420  includes first bonding regions  310  through  319  to which first wires  60  through  69  are respectively bonded. Semiconductor laser element  420  according to the present embodiment is junction-down mounted on main surface  480   a  of substrate  480 . In other words, semiconductor laser element  420  is mounted to main surface  480   a  on the semiconductor stacked body side of semiconductor laser element  420  rather than on the substrate side. 
     In the present embodiment, first bonding regions B 10  through B 19  are arranged in a staggered arrangement along the first direction. More specifically, first bonding regions B 10 , B 12 , B 14 , B 16 , and B 18  are aligned spaced at equal intervals and parallel to the first direction in the listed order. First bonding regions B 11 , B 13 , B 15 , B 17 , and B 19  are aligned spaced at equal intervals and parallel to the first direction in the listed order and are disposed between first bonding regions B 10 , B 12 , B 14 , B 16 , and B 18  on one side and second side  482  of main surface  480   a  on the other side. The positions of first bonding regions B 10  through B 19  in the first direction are mutually different, The position of first bonding region B 11  in the first direction is between the position of first bonding region B 10  in the first direction and the position of first bonding region B 12  in the first direction. The position of first bonding region B 13  in the first direction is between the position of first bonding region B 12  in the first direction and the position of first bonding region B 14  in the first direction. The position of first bonding region B 15  in the first direction is between the position of first bonding region B 14  in the first direction and the position of first bonding region B 16  in the first direction. The position of first bonding region B 17  in the first direction is between the position of first bonding region B 16  in the first direction and the position of first bonding region B 18  in the first direction. First bonding region B 19  is disposed between first bonding region B 18  and fourth side  484  of main surface  480   a.    
     The distances from front end face  420 F of semiconductor laser element  420  to the respective centers of first bonding regions B 10  and B 11  are 0.12 mm and 0.205 mm, respectively. First bonding regions B 10 , B 12 , B 14 , B 16 , and B 18  are arranged spaced at equal intervals with a center-to-center distance of 0.17 mm, and first bonding regions B 11 , B 13 , B 15 , B 17 , and B 19  are arranged spaced at equal intervals with a center-to-center distance of 0.17 mm. 
     By arranging first bonding regions B 10  through B 19  in this manner, more first bonding regions can be provided on electrode  429  of semiconductor laser element  420  while inhibiting each first bonding region (i.e., each first wire) from interfering with each other. Accordingly, more heat can be dissipated from semiconductor laser element  420  through the first bonding regions and the first wires, thereby increasing the heat dissipation efficiency of semiconductor laser device  410 , In the present embodiment, for example, the number and surface area of the first bonding regions can be doubled compared to when first bonding regions B 10  through B 14  are aligned in a single row, as they are in semiconductor laser device  310  according to Embodiment 3. Accordingly, the heat dissipation efficiency of semiconductor laser device  410  can be increased to approximately twice the heat dissipation efficiency of semiconductor laser device  310  according to Embodiment 3. 
     Moreover, by arranging first bonding regions B 10  through B 19  in a staggered arrangement, current can be supplied more uniformly to semiconductor laser element  420  via first bonding regions B 10  through B 19 . In other words, the distribution of the amount of current supplied to semiconductor laser element  120  with respect to the position in the first direction can be made uniform. 
     The size and structure of semiconductor laser element  420  are not particularly limited. In the present embodiment, the length of the resonator of semiconductor laser element  420  is 1200 μm, the width in second direction is 225 μm, and the thickness (the Z-axis direction dimension) is 85 μm. The stacked structure of semiconductor laser element  420  is the same as the stacked structure of semiconductor laser element  120  according to Embodiment 2. 
     As illustrated in  FIG. 27  and  FIG. 28 , just like in Embodiment 3, the distance from semiconductor laser element  420  to first side  481  of main surface  480   a  of substrate  480  is shorter than the distance from semiconductor laser element  420  to second side  482  in the present embodiment as well. Accordingly, it is possible to dispose more second wires (i.e., second bonding regions) in the region of main surface  480   a  from semiconductor laser element  420  to second side  482 . Similar to the arrangement of semiconductor laser element  420 , the distance from bonding member  188  to first side  481  is shorter than the distance from bonding member  188  to second side  482 . Semiconductor laser element  420  is disposed at approximately the center in the second direction of bonding member  188 . 
     The plurality of first wires  60  through  69  according to the present embodiment have the same configuration as the plurality of first wires  61  through  65  according to Embodiment 2, respectively. As illustrated in  FIG. 27 , the plurality of first wires  60  through  69  are bonded to first bonding regions B 10  through B 19  of the top surface of semiconductor laser element  420 , respectively. First wires  60  through  69  respectively include, at end portions on the semiconductor laser element  420  side, first ball portions  60 B through  69 B having a hemispherical shape. First ball portions  60 B through  69 B are bonded to semiconductor laser element  420  at first bonding regions B 10  through B 19 , respectively. In the top view of main surface  380   a,  each first wire intersects first side  481  of main surface  380   a.    
     Second wires  70  through  79  have the same configuration as second wires  70  through  79  according to Embodiment 3. 
     In the present embodiment, the number of first wires can be increased compared to Embodiment 3, and thus the current flowing per first wire can be reduced. As a result, the amount of heat generated in each first wire can be reduced, whereby melting of each first wire can be inhibited and conduction of the heat generated in each first wire to semiconductor laser element  420  can be inhibited. Moreover, since the increase in temperature of each first wire can be inhibited, heat dissipation from semiconductor laser element  420  through each first wire can be promoted. 
     For example, if the diameter of each first wire is 38 μm and the length of each second wire is 2 mm, the fusing current is approximately 4.86 A. In this case, the rated current of each first wire is set, for example, to 2.43 A, which is approximately half of the fusing current. In semiconductor laser device  310  according to Embodiment 3, when a wire of the above dimensions is used for each of the five first wires, the rated current supplied to semiconductor laser element  120  is 12.2 A. However, in the present embodiment, in order to supply a current of 12.2 A to semiconductor laser element  420 , the current supplied to each of the ten first wires can be reduced to 1.22 A. Accordingly, in the present embodiment, when a wire of the above dimensions is used for each first wire, a current (1.22 A or lower) sufficiently lower than the fusing current is supplied to each first wire, whereby heat generation in each first wire can be reduced and melting of each first wire can be inhibited. In the present embodiment, it is also possible to supply a maximum current of 24.3 A to semiconductor laser element  420  by supplying a rated current of 2.43 A to each first wire. 
     The dimensions of each first wire are not limited to the above dimensions. The dimensions of each first wire may be any dimensions as long as they are sufficient to be applicable to semiconductor laser device  410 ; for example, each first wire may have a diameter of 50 μm and a length of 3.46 mm. 
     4-2. Configuration of First Wire Group and Second Wire Group 
     Next, the first wire group and the second wire group according to the present embodiment will be described with reference to  FIG. 29 .  FIG. 29  is a schematic top view illustrating configurations of a plurality of first wire groups G 10  through G 19  and a plurality of second wire groups G 20  through G 29  according to the present embodiment. 
     As illustrated in  FIG. 29 , semiconductor laser device  410  according to the present embodiment includes a plurality of first wire groups G 10  through G 19  and a plurality of second wire groups G 20  through G 29 . 
     Each first wire group includes one or more first marks. In the present embodiment, first wire group G 10  includes first wire  60  and first mark portion M 10  (i.e., first mark  440 ). First wire group G 11  includes first wire  61  and first mark portion M 11  (i.e., first mark  441 ), First wire group G 12  includes first wire  62  and first mark portion M 12  (i.e., first mark  442 ). First wire group G 13  includes first wire  63  and first mark portion M 13  (i.e., first mark  443 ). First wire group G 14  includes first wire  64  and first mark portion M 14  (i.e., first mark  444 ). 
     First wire group G 15  includes first wire  65  and first mark portion M 15  (i.e., first mark  445 ). First wire group G 16  includes first wire  66  and first mark portion M 16  (i.e., first mark  446 ). First wire group G 17  includes first wire  67  and first mark portion M 17  (i.e., first mark  447 ). First wire group G 18  includes first wire  68  and first mark portion M 18  (i.e., first mark  448 ). First wire group G 19  includes first wire  69  and first mark portion M 19  (i.e., first mark  449 ). 
     In the top view of main surface  480   a  of substrate  480 , first wires  60  through  69  are disposed at positions overlapping first mark portions M 10  through M 19 , respectively. By placing a first mark portion at an appropriate placement position of each first wire in the top view of main surface  480   a,  the plurality of first wires  60  through  69  can be placed at appropriate positions. By inspecting whether the first wires overlap the respective first mark portions in the top view of main surface  480   a,  it is possible to determine whether the position of each of the plurality of first wires  60  through  69  is acceptable or not acceptable. 
     In the present embodiment, the plurality of first mark portions M 10  through M 19  are mutually different. Accordingly, the plurality of first wires  60  through  69  are arranged in accordance with the positions of the plurality of first mark portions that are mutually different. In addition, only one first wire overlaps each of the plurality of first mark portions, This reduces the possibility of a plurality of first wires being concentrated or contacting each other. Each second wire group includes one or more second marks. 
     Second wire groups G 20  through G 29  according to the present embodiment have the same configuration as second wire groups G 20  through G 29  according to Embodiment 3, respectively. As a result, each second wire group according to the present embodiment achieves the same advantageous effect as each wire group according to Embodiment 3. 
     Variations, etc. 
     Although the semiconductor laser device according to the present disclosure has been described above based on embodiments, the present disclosure is not limited to the above embodiments. 
     For example, in each of the above embodiments, the shape of each mark is a square or the like, but the shape of each mark is not particularly limited. For example, the shape of each mark may be a polygon, a circle, an ellipse, an oblong shape, a star, or the like. In each of the above embodiments, each mark portion includes one or two marks, but each mark portion may include three or more marks. Stated differently, a first mark portion need only include one or more first marks, and a second mark portion need only include one or more second marks. 
     When the mark portion includes three or more marks, the envelope enclosing all of the three or more marks and the region inside the envelope may be defined as the mark portion. For all combinations of two of the three or more marks, the mark portion may be determined as described with reference to  FIG. 5 , and the mark portion for all combinations added together may be defined as the mark portion containing the three or more marks. 
     Next, as an example in which there are three or more marks included in each mark portion, a variation of each second mark portion according to Embodiment 3 will be described with reference to  FIG. 30 .  FIG. 30  is a schematic top view illustrating a variation of the plurality of second mark portions M 20  through M 29  of semiconductor laser device  310  according to Embodiment 3. 
     As illustrated in  FIG. 30 , each second mark portion includes three second marks, In other words, second mark portion M 20  includes second marks  350  through  352 , second mark portion M 21  includes second marks  351  through  353 , second mark portion M 22  includes second marks  352  through  354 , second mark portion M 23  includes second marks  353  through  355 , second mark portion M 24  includes second marks  354  through  356 , second mark portion M 25  includes second marks  355  through  357 , second mark portion M 26  includes second marks  356  through  358 , second mark portion M 27  includes second marks  357  through  359 , second mark portion M 28  includes second marks  358  through  360 , second mark portion M 29  includes second marks  359  through  361 . Each second mark portion in semiconductor laser device  310  according to Embodiment 3 may thus include three second marks. This allows second mark  351  to be used, for example, in positioning second wire  70  in the first direction and inspecting the position of second wire  70  in the first direction. Stated differently, the position of second wire  70  in the first direction can be determined so that second wire  70  overlaps second mark  351  in the top view of main surface  380   a  of substrate  380 . When inspecting the position of second wire  70 , whether or not second wire  70  overlaps second mark  351  in the top view of main surface  380   a  can be used to determine whether or not the position of second wire  70  in the first direction is acceptable. The other second wires  71  through  79  can similarly be positioned in the first direction and inspected for their positions using second marks  352  through  360 , respectively. 
     As an example in which there are three or more marks included in each mark portion, an example in which there are four marks included in each mark portion will be described with reference to  FIG. 31  and  FIG. 32 .  FIG. 31  is a schematic top view illustrating the plurality of second mark portions M 20  through M 29  of semiconductor laser device  310   a  according to a variation of Embodiment 3.  FIG. 32  is a schematic top view illustrating the plurality of first mark portions M 11  through M 15  and the plurality of second mark portions M 21  through M 25  of semiconductor laser device  110   a  according to a variation of Embodiment 2. 
     Semiconductor laser device  310   a  according to a variation of Embodiment  3  illustrated in  FIG. 31  differs from semiconductor laser device  310  according to Embodiment 3 in regard to the configuration of metal film  386   a.  In addition to second marks  350  through  361 , second marks  350   a  to  359   a  are formed in metal film  386   a.    
     Second marks  350   a  through  359   a  are disposed between semiconductor laser element  120  and second side  382  of main surface  380   a.  The shape and dimensions of second marks  350   a  through  359   a  according to the present variation are the same as for each first mark according to Embodiment 1. Second marks  350   a  through  359   a  have a quadrangular shape and are in contact with the outer edge of metal film  386   a  on the second side  382  side of main surface  380   a.  Stated differently, second marks  350   a  through  359   a  are notches formed inwardly from the second side  382  side end portion of metal film  386   a.    
     Each of second mark portions M 20  through  30  according to the present variation includes four second marks. Second mark portion M 20  includes second marks  350  through  352  and  350   a,  second mark portion M 21  includes second marks  351  through  353  and  351   a , second mark portion M 22  includes second marks  352  through  354  and  352   a,  second mark portion M 23  includes second marks  353  through  355  and  353   a,  second mark portion M 24  includes second marks  354  through  356  and  354   a,  second mark portion M 25  includes second marks  355  through  357  and  355   a,  second mark portion M 26  includes second marks  356  through  358  and  356   a,  second mark portion M 27  includes second marks  357  through  359  and  357   a , second mark portion M 28  includes second marks  358  through  360  and  358   a,  and second mark portion M 29  includes second marks  359  through  361  and  359   a.    
     Each second mark portion may thus include four second marks. This allows second mark  350   a  to be used, for example, in positioning second wire  70  in the first direction and inspecting the position of second wire  70  in the first direction. Stated differently, the position of second wire  70  in the first direction can be determined so that second wire  70  overlaps second mark  350   a  in the top view of main surface  380   a  of substrate  380 . When inspecting the position of second wire  70 , whether or not second wire  70  overlaps second mark  350   a  in the top view of main surface  380   a  can be used to determine whether or not the position of second wire  70  in the first direction is acceptable. The other second wires  71  through  79  can similarly be positioned in the first direction and inspected for their positions using second marks  351   a  through  359   a,  respectively. 
     Semiconductor laser device  110   a  according to a variation of Embodiment 2 illustrated in  FIG. 32  differs from semiconductor laser device  110  according to Embodiment 1 in regard to the configuration of metal film  186   a.  In addition to first marks  141  through  146  and second marks  151  through  156 , first marks  141   a  through  146   a,  and second marks  151   a  through  156   a  are formed in metal film  186   a.    
     First marks  141   a  through  146   a  are disposed between semiconductor laser element  120  and first side  181  of main surface  180   a.  The shape and dimensions of first marks  141   a  through  146   a  according to the present variation are the same as for first marks  141  through  146 . First marks  141   a  through  146   a  are arranged in a staggered arrangement along the first direction. The positions of first marks  141   a  through  146   a  in the first direction are equal to the positions of first marks  141  through  146  in the first direction, respectively. First marks  141 ,  142   a,    143 ,  144   a,    145 , and  146   a  are aligned in a single row in the first direction and spaced at equal intervals in the first direction. First marks  141   a,    142 ,  143   a,    144 ,  145   a,  and  146  are aligned in a single row in the first direction and spaced at equal intervals in the first direction. First marks  141 ,  142   a,    143 ,  144   a,    145 , and  146   a  are disposed between first marks  141   a,    142 ,  143   a,    144 ,  145   a,  and  146  on one side and first side  181  on the other side. 
     Second marks  151   a  through  156   a  are disposed between semiconductor laser element  120  and second side  182  of main surface  180   a.  The shape and dimensions of second marks  151   a  through  156   a  according to the present variation are the same as for second marks  151  through  156 . Second marks  151   a  through  156   a  are arranged in a staggered arrangement along the first direction. The positions of second marks  151   a  through  156   a  in the first direction are equal to the positions of second marks  151  through  156  in the first direction, respectively. Second marks  151 ,  152   a,    153 ,  154   a,    155 , and  156   a  are aligned in a single row in the first direction and spaced at equal intervals in the first direction. Second marks  151   a,    152 ,  153   a,    154 ,  155   a,  and  156  are aligned in a single row in the first direction and spaced at equal intervals in the first direction. 
     Second marks  151 ,  152   a,    153 ,  154   a,    155 , and  156   a  are disposed between second marks  151   a,    152 ,  153   a,    154 ,  155   a,  and  156  on one side and second side  182  on the other side. 
     Each of first mark portions M 11  through  15  according to the present variation includes four first marks. First mark portion M 11  includes first marks  141 ,  141   a,    142 , and  142   a,  first mark portion M 12  includes first marks  142 ,  142   a,    143 , and  143   a,  first mark portion M 13  includes first marks  143 ,  143   a,    144 , and  144   a,  first mark portion M 14  includes first marks  144 ,  144   a,    145 , and  145   a,  and first mark portion M 15  includes first marks  145 ,  145   a,    146 , and  146   a.    
     Each of second mark portions M 21  through  25  according to the present variation includes four second marks. Second mark portion M 21  includes second marks  151 ,  151   a,    152 , and  152   a,  second mark portion M 22  includes second marks  152 ,  152   a,    153 , and  153   a , second mark portion M 23  includes second marks  153 ,  153   a,    154 , and  154   a,  second mark portion M 24  includes second marks  154 ,  154   a ,  155 , and  155   a,  and second mark portion M 25  includes second marks  155 ,  155   a,    156 , and  156   a.    
     Each mark portion may thus include four second marks. 
     In each of the above embodiments, the semiconductor laser element is exemplified as comprising a nitride semiconductor material, but the configuration of the semiconductor laser element is not limited to this example. The semiconductor laser element may comprise some other semiconductor material. For example, the semiconductor laser element may be a GaAs-based semiconductor laser element. 
     Various modifications of the above embodiments that may be conceived by those skilled in the art, as well as embodiments resulting from arbitrary combinations of elements and functions from different embodiments that do not depart from the essence of the present disclosure are included the present disclosure. 
     INDUSTRIAL APPLICABILITY 
     The semiconductor laser device according to the present disclosure is applicable in, for example, laser processing, as a high output power, highly efficient light source.