Patent Publication Number: US-2012025260-A1

Title: Semiconductor device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Japanese Patent Application No. 2010-168433 filed on Jul. 27, 2010, the disclosure of which including the specification, the drawings, and the claims is hereby incorporated by reference in its entirety. 
     BACKGROUND 
     The present disclosure relates to semiconductor devices, and more particularly, to semiconductor devices including a lead frame. 
     A variety of semiconductor devices in which a high-luminance and high-power light emitting element, a small-size and high-sensitivity photodetector element, etc. are packaged have been developed. The reduction of the size, power consumption, and weight of the semiconductor devices has progressed significantly. The semiconductor devices are becoming increasingly popular for use as light sources of optical printer heads, light sources of liquid crystal backlights, light sources of indicators, read sensors, etc. 
     A semiconductor device employing a light emitting diode (LED) has a small size and high efficiency and is capable of emitting light having a vivid color. The semiconductor device is free from burnout, has excellent initial drive characteristics and vibration resistance, and is resistant to repeated turning on/off. Therefore, the use of the semiconductor device as a liquid crystal backlight source of a mobile telephone and a PDA has been studied. However, as the reduction of the thickness and size of a liquid crystal display device has progressed, various problems have arisen in the semiconductor device employing an LED. 
     In the semiconductor device employing an LED, the LED chip is typically encapsulated in a molded package. Specifically, the LED chip is mounted in a package member made of a resin with external terminals of the LED chip extending outside the package member. A space around the LED chip is filled with a protective resin. There are poor tightness and adhesion between the resin package member and the metal external terminal. Therefore, a gap may occur at an interface between the package member and the external terminal, and the protective resin may leak out through the gap. The protective resin leaking outside the package member may cause burrs during cutting and forming, or various problems, such as solder defects etc. 
     To reduce or prevent the leakage of the protective resin, it has been contemplated to form a trench or protrusion which serves as a barrier to the protective resin at an interface between the external terminal and the package member (see, for example, Japanese Patent Publication No. 2006-222382). 
     SUMMARY 
     However, the above conventional technique has a problem that the technique addresses only the leakage of the protective resin through the interface between the external terminal and the package member. As the miniaturization of semiconductor devices has progressed, a space filled with the protective resin has become considerably small. Therefore, even if a slight error occurs in the amount of the protective resin filling the gap, the protective resin is likely to leak out of the package member. When a semiconductor device is mounted onto a mounting substrate, a lower surface and side surfaces of the external terminal need to be covered with a solder fillet. If the protective resin flowing over the frame-like member of the package member to leak outside the package member reaches the side surface or lower surface of the external terminal protruding outside the package member, it becomes difficult to form a solder fillet which covers the external terminal, resulting in an incorrect or defective mounting. 
     Such a problem may arise not only in semiconductor devices employing an LED, but also in any other semiconductor devices. 
     The present disclosure describes implementations of a semiconductor device in which an incorrect or defective mounting is less likely to occur even if leakage of a protective resin occurs. 
     An example semiconductor device of the present disclosure has a barrier portion at an end portion of an external terminal. 
     Specifically, the example semiconductor device includes a lead frame, a first semiconductor element mounted on a main surface of the lead frame, a frame-like member formed on the lead frame, surrounding the first semiconductor element, and a protective resin filling a space surrounded by the frame-like member. The lead frame has an external terminal protruding outside the frame-like member. The external terminal has a barrier portion which is located at an end portion thereof protruding from the frame-like member and rises from the main surface in a direction in which the first semiconductor element is mounted. 
     According to the example semiconductor device, even if the protective resin which leaks out through a gap between the frame-like member and the lead frame and the protective resin which flows over the frame-like member spread on a top surface of the external terminal, the protective resin is less likely to reach a front-end surface and a bottom surface of the external terminal. Therefore, a problem that the external terminal is not covered with a solder fillet is less likely to occur. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a plan view of a structure of a semiconductor device according to an embodiment. 
         FIG. 1B  is a cross-sectional view of the structure of the semiconductor device, taken along line Ib-Ib of  FIG. 1A . 
         FIG. 1C  is a bottom view of the structure of the semiconductor device. 
         FIG. 2  is a perspective view showing a variation of a barrier portion. 
         FIG. 3  is a perspective view showing a variation of the barrier portion. 
         FIG. 4  is a perspective view showing a variation of the barrier portion. 
         FIG. 5  is a perspective view showing a variation of the barrier portion. 
         FIGS. 6A-6C  are cross-sectional views showing variations of an external terminal. 
         FIG. 7  is a cross-sectional view showing a variation of the external terminal. 
         FIG. 8A  is a top view showing a step in a method of fabricating the semiconductor device of the embodiment. 
         FIG. 8B  is a cross-sectional view taken along line VIIIb-VIIIb of  FIG. 8A . 
         FIG. 9A  is a top view showing a step in a method of fabricating the semiconductor device of the embodiment. 
         FIG. 9B  is a cross-sectional view taken along line IXb-IXb of  FIG. 9A . 
         FIG. 10A  is a top view showing a step in a method of fabricating the semiconductor device of the embodiment. 
         FIG. 10B  is a cross-sectional view taken along line Xb-Xb of  FIG. 10A . 
         FIG. 11A  is a top view showing a step in a method of fabricating the semiconductor device of the embodiment. 
         FIG. 11B  is a cross-sectional view taken along line XIb-XIb of  FIG. 11A . 
         FIG. 12A  is a top view showing a step in a method of fabricating the semiconductor device of the embodiment. 
         FIG. 12B  is a cross-sectional view taken along line XIIb-XIIb of  FIG. 12A . 
         FIG. 13A  is a top view showing a variation of the semiconductor device of the embodiment. 
         FIG. 13B  is a cross-sectional view taken along line XIIIb-XIIIb of  FIG. 13A . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1A  is a plan view of a structure of a semiconductor device according to an embodiment.  FIG. 1B  is a cross-sectional view of the structure of the semiconductor device, taken along line Ib-Ib of  FIG. 1A .  FIG. 1C  is a bottom view of the structure of the semiconductor device. 
     As shown in  FIG. 1 , the semiconductor device of this embodiment includes a lead frame  101 , a semiconductor element  103  mounted on the lead frame  101 , a frame-like member  105  formed on the lead frame  101 , surrounding the semiconductor element  103 , and a protective resin  107  which fills a space surrounded by the frame-like member  105 . In this embodiment, the semiconductor element  103  is, but is not limited to, a light emitting diode (LED). 
     The lead frame  101  is made of, for example, a copper (Cu)-based alloy having a thickness of about  0 . 15 - 0 . 3  mm. A top surface, a bottom surface, etc. of the lead frame  101  are typically covered with a plating layer (not shown). The lead frame  101  has a die pad portion  111  on which the semiconductor element  103  is mounted and a lead portion  112  which is separated from the die pad portion  111 . The die pad portion  111  is located inside the frame-like member  105 , and has an element mounting portion  114  on which the semiconductor element  103  is mounted and an external terminal  115  which protrudes outside the frame-like member  105 . A constricted portion  116  which is narrower than the element mounting portion  114  and the external terminal  115  is formed between the element mounting portion  114  and the external terminal  115 . A through hole  111   a  is formed in the constricted portion  116 . The lead portion  112  is located inside the frame-like member  105 , and has a wire bonding portion  117  to which a wire  109  is bonded and an external terminal  115  which protrudes outside the frame-like member  105 . A constricted portion  116  which is narrower than the wire bonding portion  117  and the external terminal  115  is formed between the wire bonding portion  117  and the external terminal  115 . 
     The frame-like member  105  is made of a resin etc., and has a wall portion  151  which surrounds an outer edge portion of the lead frame  101 , a buried portion  152 A which is buried in the through hole  111   a  of the die pad portion  111 , and a buried portion  152 B which is buried in a gap between the die pad portion  111  and the lead portion  112 . The wall portion  151 , the buried portion  152 A, and the buried portion  152 B are integrally formed. In this embodiment, the frame-like member  105  is formed to cover side surfaces of the lead frame  101  and expose a bottom surface of the lead frame  101 . The outer perimeter of the wall portion  151  has a planar and rectangular shape. The external terminal  115  of the die pad portion  111  protrudes outside the frame-like member  105  from one of the shorter sides, and the external terminal  115  of the lead portion  112  protrudes outside the frame-like member  105  from the other shorter side. 
     The semiconductor element  103  is mounted on the element mounting portion  114  of the die pad portion  111 . In  FIG. 1 , a back electrode (not shown) is formed on a back surface of the semiconductor element  103 , and the back electrode and the element mounting portion  114  are bonded together by a conductive paste, such as solder etc. In this embodiment, the element mounting portion  114  of the die pad portion  111  spreads on both sides of a center line passing through a middle in a longitudinal direction of the frame-like member  105 , and the semiconductor element  103  is disposed at a center of a region surrounded by the frame-like member  105 . In this embodiment, the entire semiconductor device including the external terminals  115  protruding outside the frame-like member  105  are axially symmetric, and therefore, the semiconductor element  103  is disposed at a center of the semiconductor device. A top electrode (not shown) is formed on a top surface of the semiconductor element  103 . The top electrode and the wire bonding portion  117  of the lead portion  112  are connected together via the wire  109 . 
     The space surrounded by the frame-like member  105  is filled with the protective resin  107  which is a transparent resin. As a result, the semiconductor element  103  and the wire  109  are encapsulated. The protective resin  107  may contain a fluorescent material which absorbs light emitted by the semiconductor element  103  to emit light having a different wavelength. 
     The external terminals  115  of the die pad portion  111  and the lead portion  112  each have a barrier portion  119  raised from the top surface at an end portion thereof opposite to the frame-like member  105 . If the protective resin  107  flows over the frame-like member  105  or leaks out from an interface between the frame-like member  105  and the lead frame  101 , the protective resin  107  spreads on the top surface of the external terminal  115 . If the barrier portion  119  is not provided, then when the amount of a leaking protective resin is large, the leaking protective resin reaches a side surface of the external terminal  115 . If the amount is still larger, the protective resin reaches a back surface of the external terminal  115 . When soldering is performed on the semiconductor device, the side and bottom surfaces of the external terminal  115  are covered with a solder fillet. Of the side surfaces of the external terminal  115 , an end surface (front-end surface)  115   a  of the end portion of the external terminal  115  protruding from the frame-like member  105  is more important than side end surfaces  115   b  when soldering is performed on the semiconductor device. If the protective resin adheres to the front-end surface  115   a,  the formation of the solder fillet becomes insufficient, so that a faulty connection may occur or the bonding strength may decrease. However, because the semiconductor device of this embodiment has the barrier portion  119 , the protective resin flowing onto the front-end surface  115   a  can be reduced or prevented. 
     The barrier portion  119  may be formed in any manner. For example, if the lead frame  101  is cut off a rail under conditions that burrs are likely to occur, the barrier portion  119  having a height of about several micrometers to about 10 μm can be formed at the end portion of the lead frame  101 . Alternatively, when plating is performed on a surface of the lead frame  101 , then if only a predetermined portion of the plating layer is caused to be thicker, the barrier portion  119  may be formed. Alternatively, after plating, the lead frame may be cut off in a manner which allows the plating layer to be peeled and lifted at the end portion of the lead frame  101 , whereby the barrier portion  119  made of the plating layer may be formed at the end portion. In addition to these techniques, the barrier portion  119  may be formed by attaching a member made of a resin, a metal, etc. to a predetermined portion. When the barrier portion  119  is formed as burrs, the barrier portion  119  is made of the same material as that of the lead frame. Alternatively, the barrier portion  119  may be made of a multilayer including the material of the base and the material of the plating layer. 
     A preferable height from the top surface of the external terminal  115  to a top end of the barrier portion  119  are several micrometers, but varies depending on the viscosity of the protective resin. If the height is about  1 - 2  p.m or more, the effect of reducing or preventing the overflow of the protective resin is obtained. The effect increases with an increase in the height, but it is difficult to form the barrier portion  119  having an excessive height. Even when the barrier portion  119  is formed as burrs or plating, then if the height is about  10  p.m, the barrier portion  119  can be easily formed. In particular, when the barrier portion  119  is formed as burrs, then if the height is about one thirtieth of the thickness of the lead frame  101 , the barrier portion  119  can be easily formed. 
     The barrier portion  119  does not need to have a flat top surface. As shown in  FIG. 2 , the top surface may have a sawtooth shape having a plurality of crests and troughs. A height from the top surface of the external terminal  115  to a top end of the trough is lower than a height from the top surface of the external terminal  115  to a top end of the crest. Even when there are the troughs having such a lower height, surface tension occurs between the crest and the trough, and therefore, the leakage reduction or prevention effect can be expected at a similar or higher level than that of the flat barrier portion  119 . 
       FIG. 1  shows the example in which the barrier portion  119  is formed at an end portion protruding from the frame-like member  105  to protect the most important front-end surface  115   a  of the external terminal  115 . As shown in  FIG. 3 , however, the barrier portion  119  may be formed to surround the outer edge portion of the external terminal  115  excluding a side thereof closer to the frame-like member  105 . In this case, it is possible to reduce or prevent the overflow of the protective resin not only to the front-end surface  115   a  of the external terminal  115 , but also to the side end surface  115   b  of the external terminal  115 . Note that the top end portion of the barrier portion  119  may have a sawtooth shape. 
     A width (protrusion width) of the external terminal  115  in a direction along the longer side of the frame-like member  105 , and a width of the external terminal  115  in a direction along the shorter side of the frame-like member  105 , may be set to any values. For example, the width of the external terminal  115  in a direction along the shorter side of the frame-like member  105  may be greater than or equal to the length of the shorter side of the frame-like member  105 . Alternatively, as shown in  FIG. 4 , the external terminal  115  may have a concave portion  121  which has a smaller protrusion width than those of portions (convex portions  122 ) on both sides of the concave portion  121 . In this case, the solder fillet can be trapped by the concave portion  121  and the convex portions  122  on both sides of the concave portion  121 , so that soldering can be more easily performed. In addition, when the lead frame  101  is cut off the rail, mechanical stress applied to the lead frame  101  can be reduced. Also in this case, the barrier portion  119  may have a sawtooth top end portion, or the barrier portion  119  may be formed to surround the outer edge portion of the external terminal  115 . Alternatively, the barrier portion  119  may not be formed at a center portion of the external terminal  115 . Also in this case, the most important front-end surface  115   a  can be protected. Moreover, as shown in  FIG. 5 , the concave portion  121  may not protrude from the frame-like member  105 . A width of the concave portion  121  in a direction along the shorter side of the frame-like member  105  may be set to any value and may be greater than that of the convex portion  122 . The convex portions  122  do not need to have the same size. A plurality of concave portions  121  may be provided at a center, and three or more convex portions  122  may be provided. 
     The front-end surface  115   a  of the external terminal  115  may have a notch portion at a lower portion thereof. By providing the notch portion, solder and the external terminal  115  can be more firmly bonded together. As shown in  FIG. 6A , the notch portion may be formed by beveling, or cutting at an inclination, a lower end portion of the front-end surface  115   a,  in a cross-section thereof in the protrusion direction of the frame-like member  105 . Alternatively, the bevel may have a curved shape ( FIG. 6B ) or an L-shape ( FIG. 6C ). By providing such a notch portion at the lower portion of the external terminal  115 , the solder fillet can be more easily trapped (anchoring effect). The notch portion may extend over about half, or more than half, the front-end surface. Even if the notch portion extends over less than half the front-end surface, the anchoring effect can be obtained. 
     Typically, a plating layer  123  is formed on the top, back, and side surfaces of the lead frame  101  by a plating process. The plating process is typically performed before the lead frame  101  is cut off the rail. Therefore, the plating layer  123  is typically not formed on the front-end surface  115   a  of the external terminal  115 , so that the base is exposed. When the notch portion is formed, the plating layer is formed on the notch portion as shown in  FIGS. 6A-6C . Moreover, as shown in  FIG. 7 , if the plating layer  123  is also formed on a portion of the front-end surface  115   a  of the external terminal  115 , the anchoring effect which allows a solder fillet to be easily trapped can be enhanced. For example, as shown in  FIG. 7 , the plating layer  123  may be provided on a portion of the front-end surface  115   a  of the external terminal  115  by reducing the thickness of a portion where the lead frame  101  is attached to the rail  201 , forming the plating layer  123 , and cutting the attachment portion. 
     When the external terminal  115  is cut off the rail  201  after the plating layer  123  is formed, then if the plating layer  123  is peeled and lifted, the barrier portion  119  made of the plating layer  123  can be formed as shown in  FIGS. 6A-6C  and  FIG. 7 . Note that the plating layer  123  may be made of lead-free solder, gold, silver, nickel, etc. In the case of silver, a sulfuration prevention process may be further performed. Alternatively, the plating layer  123  may be made of a multilayer of nickel and silver, a multilayer of nickel, gold, and silver, etc. 
       FIGS. 8A-12B  show a method for fabricating the semiconductor device of this embodiment in the order in which the device is fabricated. Initially, as shown in  FIGS. 8A and 8B , the lead frame  101  which is attached to the rail  201  is formed at a predetermined portion of a base by etching, stamping, etc. Thereafter, plating is optionally performed to form a plating layer (not shown). Note that plating may be performed before the etching or stamping process. The lead frame  101  is not limited to any particular shape, but is assumed to have a structure described below. 
     The die pad portion  111  of the lead frame  101  has the element mounting portion  114 , the external terminal  115 , and the constricted portion  116  formed between the external terminal  115  and the element mounting portion  114 . The constricted portion  116  is narrower than the element mounting portion  114  and the external terminal  115 . The through hole  111   a  is formed at a center portion of the constricted portion  116 . An opening  201  a is formed at a portion where the external terminal  115  is attached to the rail  201 , so that the attachment portion of the external terminal  115  and the rail  201  is narrowed. A groove  201   b  is formed in the back surface of the attachment portion. A lower portion of an end portion on the element mounting portion  114  side of the die pad portion  111  is removed to form a thin portion  114   a  which is thinner than the other portion of the die pad portion  111 . In  FIG. 8 , the external terminal  115  is as wide as the element mounting portion  114 . Alternatively, the external terminal  115  may be wider or narrower than the element mounting portion  114 . The lead portion  112  is formed, facing the end portion on the element mounting portion  114  side of the die pad portion  111 , with a space between the lead portion  112  and the die pad portion  111 . The lead portion  112  has the wire bonding portion  117 , the external terminal  115 , and the constricted portion  116  formed between the wire bonding portion  117  and the external terminal  115 . An opening  201   a  is formed at a portion where the external terminal  115  is attached to the rail  201 . A groove  201   b  is formed in the back surface of the attachment portion. In  FIG. 8 , the external terminal  115  is as wide as the wire bonding portion  117 . Alternatively, the external terminal  115  may be wider or narrower than the wire bonding portion  117 . The external terminal  115  of the lead portion  112  may or may not be as wide as the external terminal  115  of the die pad portion  111 . Next, as shown in  FIG. 9 , the frame-like member  105  is formed. The frame-like member  105  may be formed by, but not limited to, commonly used insert molding, etc. The frame-like member  105  may be made of, for example, a thermoplastic resin containing a polyamide etc. as a major component or a thermosetting resin containing silicone etc. as a major component. Alternatively, the frame-like member  105  may be made of other resin materials. In the molding process, the frame-like member can be easily formed using the through hole  111   a  of the die pad portion  111  as a gate for injection of the resin. The frame-like member  105  is formed along the outer edge portion of the lead frame  101 , and has the wall portion  151  rising from the top surface of the lead frame  101 , the buried portion  152 A buried in the through hole  111   a  of the die pad portion  111 , and the buried portion  152 B buried between the die pad portion  111  and the lead portion  112 . A shorter side of the frame-like member  105  is positioned on the constricted portion  116 , leaving the external terminal  115  to protrude outside the frame-like member  105 . 
     If an inner wall of the wall portion  151  is allowed to have a sloped surface, the wall portion  151  is easily molded. If the buried portion  152 A is allowed to have a top surface sloped at an angle smaller than that of the inner wall of the wall portion  151 , the buried portion  152 A is easily formed. If the bottom surface of the buried portion  152 A is located higher than the bottom surface of the die pad portion  111 , an inner wall surface of the through hole  111   a  is expected to provide the anchoring effect during soldering. Note that the bottom surfaces of the buried portion  152 A and the die pad portion  111  may form a flat surface. The adhesion between the frame-like member  105  and the lead frame  101  may decrease when the frame-like member  105  is formed of some resin materials. In this embodiment, however, the lead frame  101  has the constricted portion  116 , the through hole  111   a,  the thin portion  114   a,  etc. This structure can enhance the adhesion between the frame-like member  105  and the lead frame  101 . The strength of the frame-like member  105  can also be enhanced. Therefore, even when a thermoplastic resin, which has excellent recyclability, is used, a sufficient level of adhesion and strength can be ensured. Note that not all of the constricted portion  116 , the through hole  111   a,  the thin portion  114   a,  etc. are required, and only a portion or none of them may be provided. 
     Next, as shown in  FIG. 10 , the semiconductor element  103  is fixed to the element mounting portion  114 . Thereafter, the electrode provided on the top surface of the semiconductor element  103  is connected to the wire bonding portion  117  of the lead portion  112  via the wire  109 . When the semiconductor element  103  has a back electrode, the semiconductor element  103  may be fixed using a conductive paste, such as solder etc. When the semiconductor element  103  does not have a back electrode, a portion of the element mounting portion  114  may be used as a bonding pad to connect the electrode formed on the top surface of the semiconductor element  103  to the die pad portion  111  via a wire. When the semiconductor element  103  is a light emitting element, a photodetector element, etc., the semiconductor element  103  is preferably mounted at a center of the frame-like member  105 . To this end, the die pad portion  111  preferably extends from one of the shorter sides of the frame-like member  105  to a midpoint between the middle of the longer side and the other shorter side. Note that some types of semiconductor elements do not necessarily need to be mounted at a center of the frame-like member  105 . 
     Next, as shown in  FIG. 11 , the lead frame  101  is cut off the rail  201  at the groove  201   b.  In this case, if a cutting blade is moved upward from the back surface in which the groove  201   b  is formed, burrs projecting upward occur on the top surface of the external terminal  115  to form the barrier portion  119 . Alternatively, the barrier portion  119  may be formed by peeling and lifting a plating layer. Note that the barrier portion  119  may be formed by causing burrs to occur when the opening  201   a  is formed. The barrier portion  119  may be a separate part which is attached to the top surface of the external terminal  115 . A notch portion may be formed at an end portion of the external terminal  115  by previously forming a V-shaped groove  201   b.    
     Next, as shown in  FIG. 12 , a space inside the frame-like member  105  is filled with the protective resin  107 . Even if the protective resin  107  leaks out, the barrier portion  119  makes it difficult for the protective resin  107  to reach the end surface and back surface of the external terminal  115 , so that a defect can be reduced or prevented. Note that an electrical characteristic may be optionally tested after the lead frame  101  is cut off the rail  201  and before the space inside the frame-like member  105  is filled with the protective resin  107 . 
     Note that the process, the structure of the lead frame  101 , etc. may be modified and changed as appropriate. For example, the lead frame  101  may be cut off the rail  201  before the semiconductor element  103  is mounted. A thin portion may be provided in the lead portion  112  in addition to the die pad portion  111 . 
     Although an example in which a single semiconductor element is mounted has been described above, a plurality of semiconductor elements may be mounted on the die pad portion  111 . If a plurality of semiconductor elements for which optical characteristics are required, such as light emitting elements, photodetector elements, etc., are mounted, the semiconductor elements are preferably disposed at axially symmetric positions with respect to a center line passing through a middle in the longitudinal direction of the frame-like member  105 . Specifically, as shown in  FIG. 13 , a distance dl between the center line and a first semiconductor element  103 A and a distance d 2  between the center line and a second semiconductor element  103 B may be set to be equal to each other. When a plurality of semiconductor elements are mounted, the size of the die pad portion  111  increases. Therefore, in order to reduce the size of the semiconductor device, the space between the die pad portion  111  and the lead portion  112  needs to be reduced. In this case, in order to reduce or prevent a short circuit caused by a solder bridge on the back surface of the lead frame  101 , a thin portion  114   a  and a thin portion  117   a  are preferably provided at an end portion of the die pad portion  111  closer to the lead portion  112  and an end portion of the lead portion  112  closer to the die pad portion  111 , respectively. With this structure, a short circuit is less likely to occur, and in addition, the adhesion between the frame-like member  105  and the lead frame  101  can be enhanced. Also, at least a portion of the second semiconductor element  103 B closer to the lead portion  112  than to the center line is preferably disposed on the thin portion  114   a.  As a result, the area of the die pad portion  111  can be reduced while a sufficient region where the semiconductor element(s)  103  is mounted is ensured. 
     Although an example in which only a semiconductor element is mounted on a lead frame has been described above, a resistor, a capacitor, etc. may be mounted together with the semiconductor element. Although an example in which two external terminals are formed has been described above, a plurality of lead portions and three or more external terminals may be formed. The semiconductor element is not limited to light emitting elements (e.g., light emitting diodes, superluminescence diodes, laser diodes, etc.), photodetector elements, etc., and may be other types of transistors, diodes, sensors, etc. The protective resin may optionally be made of a light shield material. Although an example in which the back surface of the lead frame is exposed has been described above, at least a portion of the back surface of the lead frame may be covered by the frame-like member. Although an example in which a semiconductor device has a rectangular frame-like member has been described above, a square frame-like member may be employed. Alternatively, the frame-like member may be in the shape of a polygon, a circle, an ellipse, an oval, etc. 
     As described above, in the semiconductor device of the present disclosure, even if a protective resin leaks out, an incorrect or defective mounting is less likely to occur. The present disclosure is particularly useful for semiconductor devices including a lead frame.