Abstract:
A semiconductor light emitting apparatus comprises: a first lead having a recess; a second lead; embedding resin that embeds therein a portion of the first lead and a portion of the second lead; a semiconductor light emitting device; a wire connecting the semiconductor light emitting device to the second lead; and sealing resin that seals the semiconductor light emitting device and the wire. The semiconductor light emitting device is housed in the recess and has a generally identical shape and size relative to the recess.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2004-246114, filed on Aug. 26, 2004, and the Japanese Patent Application No. 2005-240433, filed on Aug. 22, 2005; the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to a semiconductor light emitting apparatus such as a light emitting diode (LED), and more particularly to a semiconductor light emitting apparatus that enables high brightness and reliability by improving heat dissipation and relieving stress from resin.  
         [0004]     2. Background Art  
         [0005]     In recent years, semiconductor light emitting apparatuses have been widely used for various light sources including illumination lamps and displays. In particular, realization of green and blue LEDs has dramatically extended its application to backlights used in liquid crystal displays of mobile phones or other devices. In mobile device applications, a package of the surface mount type called “SMD (Surface Mount Device)” is vital to high density mounting on a circuit board. In order to meet these requirements, various semiconductor light emitting apparatuses of the surface mount type are developed (see, e.g., Japanese Laid-Open Patent Application 2003-8077).  
         [0006]     A light emitting apparatus of the surface mount type can be made very thin in its entirety because it is formed from a pair of leads and resin. Such a compact light emitting apparatus of the surface mount type is also suitable to commercial production, and has been used in a wide range of applications.  
         [0007]     However, optical output required for a semiconductor light emitting apparatus has been ever increasing. This leads to requirements for large current driving, and hence for further improvement of heat dissipation from the light emitting device. Moreover, applications are increasingly used in severer ambient conditions. Specifically, for example, there is a problem of stress to a light emitting device chip due to expansion and contraction of sealing resin associated with varying ambient temperature. Yielding to this stress, the chip may be stripped off from the lead frame, or subjected to cracks.  
       SUMMARY OF THE INVENTION  
       [0008]     According to an aspect of the invention, there is provided a semiconductor light emitting apparatus comprising: a first lead having a recess; a second lead; an embedding resin that embeds therein a portion of the first lead and a portion of the second lead; a semiconductor light emitting device housed in the recess and having a generally identical shape and size relative to the recess; a wire connecting the semiconductor light emitting device to the second lead; and a sealing resin that seals the semiconductor light emitting device and the wire.  
         [0009]     According to other aspect of the invention, there is provided a semiconductor light emitting apparatus comprising: a first lead; a support provided on the first lead and having a recess; a second lead; an embedding resin that embeds therein a portion of the first lead and a portion of the second lead; a semiconductor light emitting device housed in the recess and having a generally identical shape and size relative to the recess; a wire connecting the semiconductor light emitting device to the second lead; and a sealing resin that seals the semiconductor light emitting device and the wire.  
         [0010]     According to other aspect of the invention, there is provided a semiconductor light emitting apparatus comprising: A semiconductor light emitting apparatus comprising: a support made of insulating material and having a recess; a first conductive pattern provided on the surface of the support; a second conductive pattern provided on the surface of the support; a semiconductor light emitting device housed in the recess and having a generally identical shape and size relative to the recess; a wire connecting the semiconductor light emitting device to one of the first and second conductive patterns; and a sealing resin that seals the semiconductor light emitting device and the wire. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1A  is a schematic view illustrating the cross-sectional structure of a semiconductor light emitting apparatus according to an embodiment of the invention;  
         [0012]      FIG. 1B  is a top view showing the semiconductor light emitting apparatus from which sealing resin  40  thereof is removed;  
         [0013]      FIG. 2  is a schematic view showing the cross-sectional structure of a semiconductor light emitting apparatus of a comparative example investigated by the inventors in the course of reaching the invention;  
         [0014]      FIG. 3A  is a partially enlarged cross section of the first lead  10  of the semiconductor light emitting apparatus of the embodiment of the invention;  
         [0015]      FIG. 3B  is a schematic cross section of the semiconductor light emitting device  50  bonded to the bottom face of the recess  18 ;  
         [0016]      FIG. 4  is a graphical diagram showing the relation between the thickness of the sealing resin  40  and stress to the semiconductor light emitting device  50 ;  
         [0017]      FIG. 5  is a schematic view illustrating the cross-sectional structure of a semiconductor light emitting device that can be mounted on the semiconductor light emitting apparatus of the embodiment of the invention;  
         [0018]      FIG. 6  is a schematic cross section showing a second example of the embodiment of the invention;  
         [0019]      FIG. 7  is a schematic cross section showing a third example of the embodiment of the invention;  
         [0020]      FIGS. 8A and 8B  are schematic views showing a fourth example of the embodiment of the invention;  
         [0021]      FIG. 9  is a schematic cross section showing a fifth example of the embodiment of the invention;  
         [0022]      FIG. 10  is a schematic cross section showing a sixth example of the embodiment of the invention;  
         [0023]      FIG. 11  is a schematic view for illustrating heat dissipation in the semiconductor light emitting apparatus of the fifth example;  
         [0024]      FIGS. 12A and 12B  are schematic cross sections showing a seventh example of the invention;  
         [0025]      FIGS. 13A and 13B  are schematic views showing an eighth example of the invention;  
         [0026]      FIG. 14  is a schematic perspective view of a semiconductor light emitting apparatus of the eighth example;  
         [0027]      FIG. 15  is a schematic cross section of a semiconductor light emitting apparatus of a ninth example;  
         [0028]      FIG. 16  is a schematic cross section of a semiconductor light emitting apparatus of a tenth example;  
         [0029]      FIG. 17  is a schematic cross section of a semiconductor light emitting apparatus of an eleventh example;  
         [0030]      FIG. 18  is a schematic cross section of a semiconductor light emitting apparatus of a twelfth example;  
         [0031]      FIG. 19  is a schematic cross section of a semiconductor light emitting apparatus of a thirteenth example; and  
         [0032]      FIG. 20  is a schematic cross section of a semiconductor light emitting apparatus of an example of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0033]     Embodiments of the invention will now be described with reference to the drawings.  
         [0034]      FIG. 1A  is a schematic view illustrating the cross-sectional structure of a semiconductor light emitting apparatus according to an embodiment of the invention.  
         [0035]      FIG. 1B  is a top view showing the semiconductor light emitting apparatus from which sealing resin  40  thereof is removed.  
         [0036]     At least a portion of a first lead  10  and a second lead  11  is embedded in high thermal conductive resin  20  (e.g., made of epoxy-based material). The leads  10  and  11  may be connected as a lead frame, for example, during the manufacturing process, and embedded into the high thermal conductive resin  20  either before or after the bonding process for a semiconductor light emitting device  50 . The leads  10  and  11  are preferably made of materials such as copper, copper-based alloy, or iron-based alloy.  
         [0037]     The lead  10  has a recess  18  formed on the upper face thereof, in which the semiconductor light emitting device  50  is housed. The semiconductor light emitting device  50  has a generally identical shape and size relative to the recess  18 . More specifically, in this example, the recess  18  is shaped as a truncated pyramid expanding toward its upper opening. The semiconductor light emitting device  50  also has a generally identical size and is shaped as a truncated pyramid with its sides expanding upward.  
         [0038]     A first electrode  70  is formed on the upper face of the semiconductor light emitting device  50  and bonded to the second lead  11  with a wire  35  such as Au (gold) wire. The outer periphery of the high thermal conductive resin  20  embedding the leads  10  and  11  therein is provided with photoreflective resin  30  that is formed with a bevel for reflecting light. By way of example, the photoreflective resin  30  may include polymer resin containing titanium oxide. These are sealed with sealing resin  40  for protecting the semiconductor light emitting device  50  and the bonding wire  35 . Examples of transparent sealing resin  40  may include epoxy-based resin and silicone. Phosphors can be dispersed in the sealing resin  40  to convert the wavelength of primary light from the semiconductor light emitting device  50  into secondary light to be extracted with a desired wavelength.  
         [0039]     According to this embodiment, the semiconductor light emitting device  50  can be housed in the recess  18  of the lead  10  to alleviate the stress applied from the sealing resin  40  and eliminate the problem of stripping and cracking of the semiconductor light emitting device  50 .  
         [0040]     In the example shown in  FIG. 1B , the wire  35  extends in an oblique direction relative to a direction along which the first and second leads are disposed. That is, the wire  35  extends not right aside (in a direction along which the leads  10  and  11  are disposed and extend) but in an oblique direction from the semiconductor light emitting device  50  toward the lead  11 . Thus, a breaking of the wire  35  can be prevented because the length of the wire  35  can be increased. For example, if the body of the sealing resin  20  expands the leads  10  and  11  slant upward and the spacing between the leads  10  and  11  increases. Even in such a case, breaking of the wire  35  can be prevented by extending the wire  35  in an oblique direction as shown in  FIG. 1B .  
         [0041]      FIG. 2  is a schematic view showing the cross-sectional structure of a semiconductor light emitting apparatus of a comparative example investigated by the inventors in the course of reaching the invention.  
         [0042]     This package has a pair of leads  16  and  17 . A light emitting device  50  is bonded onto the lead  16  with conductive silver paste (not shown). An electrode  70  provided on the light emitting device  50  is bonded to the other lead  17  by wire bonding  35 . The leads  16  and  17  are fixed to highly conductive resin  20 . Highly reflective resin  30  is further provided to form a light reflecting plate. The light emitting device  50  is sealed with sealing resin  40  after wire bonding.  
         [0043]     However, in this comparative example, the semiconductor light emitting device  50  is mounted on the lead  16  and sealed with the sealing resin  40  around its periphery. Therefore the semiconductor light emitting device  50  is directly subjected to stress associated with expansion and contraction of the resin  40 , and may be stripped off or subjected to cracks. In addition, heat dissipation from the semiconductor light emitting device  50  has room for improvement.  
         [0044]     In contrast, according to this embodiment, the semiconductor light emitting device  50  can be housed in the recess  18  of the lead  10  to relieve the stress from the sealing resin  40  and also improve heat dissipation. This point will now be described with illustrating more detailed structures.  
         [0045]      FIG. 3A  is a partially enlarged cross section of the first lead  10  of the semiconductor light emitting apparatus of this embodiment.  
         [0046]     The lead  10  has a recess  18  pressed or etched in accordance with the shape of the light emitting device  50 . The recess  18  may be shaped as a rectangular parallelepiped, a truncated pyramid, or a combination thereof.  
         [0047]      FIG. 3B  is a schematic cross section of the semiconductor light emitting device  50  bonded to the bottom face of the recess  18 .  
         [0048]     As shown in this figure, preferably, the sidewall  19  of the recess  18  is close to the side face of the light emitting device  50 . To meet the need for bonding the light emitting device  50  by die bonding, the recess  18  preferably has a shape expanding upward or a vertical sidewall. The depth of the recess  18  is preferably about the sum of the thickness of the light emitting device  50  and the thickness of metal eutectic solder or silver paste  37 .  
         [0049]     The shape of the vertical cross section of the semiconductor light emitting device  50  that is cut along a vertical plane intersecting the surface where the first electrode  70  is provided, is preferably approximated to the shape of the vertical section of the recess  18 . That is, the spacing between the semiconductor light emitting device  50  and the sidewall  19  of the recess  18  is preferably small.  
         [0050]      FIG. 4  is a graphical diagram showing the relation between the thickness of the sealing resin  40  and stress to the semiconductor light emitting device  50 . More specifically, this figure shows the influence of stress to a chip (semiconductor light emitting device  50 ) on the thickness of the sealing resin  40  interposed between the semiconductor light emitting device  50  and the sidewall  19  of the recess  18 . Table 1 is a list summarizing the relation shown in  FIG. 4 . In this example, epoxy resin is used for the sealing resin  40 .  
                                         TABLE 1                                   RESIN THICKNESS (mm)   STRESS TO CHIP (Pa)                                        0.01   1.85 × 10 7             0.03   3.70 × 10 7             0.06   5.00 × 10 7             0.1   5.54 × 10 7             0.3   5.63 × 10 7             0.5   5.71 × 10 7                          
         [0051]     It is to be appreciated from  FIG. 4  and Table 1 that stress to the chip sharply decreases when the thickness of the sealing resin  40  interposed between the semiconductor light emitting device  50  and the sidewall  19  of the recess  18  falls below 0.1 millimeter. The term “generally identical shape and size” used herein means that the difference of length of the side, difference of height, or gap between the semiconductor light emitting device  50  and the sidewall  19  falls within the range of thickness of sealing resin in which stress to the chip sharply decreases. That is, the thickness of the sealing resin  40  interposed between the semiconductor light emitting device  50  and the sidewall  19  of the recess  18  is preferably 0.1 millimeter or less.  
         [0052]     In this case, since the sidewall  19  of the recess is located close to the side face of the semiconductor light emitting device  50 , stress due to expansion and contraction of the sealing resin  40  does not directly affect the semiconductor light emitting device  50 . As a result, stripping and cracking of the semiconductor light emitting device  50 , and hence degradation of its emission characteristics, can be prevented.  
         [0053]     In addition, heat generated in the semiconductor light emitting device  50  can be dissipated toward the sidewall  19  of the recess to maintain stable emission characteristics even for large current driving.  
         [0054]     Moreover, by configuring the semiconductor light emitting device  50  to have a generally identical size relative to the recess  18 , the mounting position of the semiconductor light emitting device  50  can be precisely defined. That is, the position of the recess  18  directly corresponds to the mounting position of the semiconductor light emitting device  50 . Therefore, when the semiconductor light emitting device  50  is optically coupled to a lens or optical fiber, no loss due to its mounting position deviation will occur, and advantageously, optical coupling as designed can be always achieved.  
         [0055]     Furthermore, according to this embodiment, light emitted laterally or downward from the semiconductor light emitting device  50  can be reflected and extracted upward. For example, in the example shown in  FIG. 3B , among the light beams emitted from a light emitting layer (not shown) included in the semiconductor light emitting device  50 , the light beams emitted upward can be directly extracted outside. On the other hand, the light beams emitted in lateral or obliquely lateral directions from the light emitting layer of the semiconductor light emitting device  50  can be reflected by the sidewall  19  of the recess  18  and extracted upward. That is, the sidewall  19  of the recess  18  can be used as a reflecting plate to increase the light extraction efficiency. This effect is especially more significant when the substrate material used for the semiconductor light emitting device  50  is transparent to emission wavelength than when it is opaque. For example, when the emission wavelength is visible light, a substrate of the semiconductor light emitting device  50  made of GaAs is opaque to the emission wavelength. However, a substrate made of GaP or GaN is transparent to the emission wavelength. In this case, improvement of light extraction efficiency by reflection at the sidewall  19  can be achieved more significantly.  
         [0056]     When a predefined clearance between the semiconductor light emitting device  50  and the sidewall  19  of the recess  18  is required for die bonding the semiconductor device  50  in the recess  18 , this can be taken into consideration to determine an optimal spacing.  
         [0057]     In addition, as shown in  FIG. 3B , the gap between the semiconductor light emitting device  50  and the recess sidewall  19  may be filled with high thermal conductive resin  140 . In this case, heat generated in the semiconductor light emitting device  50  can be dissipated through the high thermal conductive resin  140  toward the recess sidewall  19 , which enables improvement of temperature characteristics. As a result, for example, thermal resistance, which is about 180° C./W for the structure of the comparative example shown in  FIG. 2 , can be improved to about 80° C./W.  
         [0058]     The bonding wire  35 , which is sealed in the sealing resin  40 , can have a sufficiently large loop length to absorb stress due to expansion and contraction of resin.  
         [0059]     In this way, the rate of lighting failure, which is about 10% resulting from the solder reflow process at 260° C. for a light emitting device of the comparative example shown in  FIG. 2 , can be reduced to 1% or less.  
         [0060]      FIG. 5  is a schematic view illustrating the cross-sectional structure of a semiconductor light emitting device that can be mounted on the semiconductor light emitting apparatus of this embodiment.  
         [0061]     In this example, the semiconductor light emitting device is shaped generally as a truncated pyramid in accordance with the expanding shape of the recess  18  as illustrated in  FIGS. 1A and 1B , and  3 A and  3 B. The internal structure thereof is described as follows. On one major surface of a transparent substrate  90  is formed a light emitting layer  80 , below which is formed a second electrode  60  that also serves as a highly reflective layer. A first electrode  70  is formed on the upper face of the transparent substrate  90 . A highly reflective layer  100  including dielectric film is formed on the side face of the transparent substrate  90 .  
         [0062]     As illustrated in  FIG. 3B , the second electrode  60  is die bonded to the lead  10  with solder paste, or AuSn or other eutectic solder  37 . The gap between the recess sidewall  19  and the side face of the light emitting device  50  is filled with thin, high thermal conductive resin  140 . The first electrode  70  is connected to the second lead  11  via the bonding wire  35 . Light emitted from the semiconductor light emitting layer  80  has various components including a component that travels through the transparent substrate  90  and exits out of the light emitting device, a component that is reflected by the side face reflecting layer  100  and exits outside, and a component that is reflected by the lower, second electrode  60  and exits outside. Note that without the reflecting layer  100  on the side face of the light emitting device, a similar effect can be achieved if the sidewall  19  of the recess is highly reflective.  
         [0063]      FIG. 6  is a schematic cross section showing a second example of the embodiment of the invention. With regard to this figure, elements similar to those described above with reference to  FIGS. 1A  to  5  are marked with the same reference numerals and will not be described in detail.  
         [0064]     In this example again, the lead  10  has a recess  18  formed on the upper face thereof, in which the semiconductor light emitting device  50  is housed. However, two electrodes (not shown) are provided on the upper face of the semiconductor light emitting device  50 . These two electrodes are connected to the leads  11  and  10  via wires  35  and  36 , respectively. This is an effective structure when, for example, the semiconductor light emitting device  50  is configured to be formed on an insulating substrate.  
         [0065]     In this example again, the semiconductor light emitting device  50  is housed in the recess  18  to avoid much sealing resin  40  from entering the gap between the inner wall surface of the recess  18  and the semiconductor light emitting device  50 . As a result, the semiconductor light emitting device  50  can be protected against stress of expansion and contraction of the sealing resin  40 . At the same time, heat dissipation from the semiconductor light emitting device  50  to the lead  10  can be facilitated to achieve stable large current driving.  
         [0066]      FIG. 7  is a schematic cross section showing a third example of the embodiment of the invention. With regard to this figure, elements similar to those described above with reference to  FIGS. 1A  to  5  are marked with the same reference numerals and will not be described in detail.  
         [0067]     In this example again, the lead  10  has a recess  18 , in which the semiconductor light emitting device  50  is housed. The semiconductor light emitting device  50  has a generally identical shape and size relative to the recess  18 , but their shapes are not exactly identical. More specifically, asperities  120  are provided on the side face of the semiconductor light emitting device  50  to decrease total reflection of light inside the device, thereby increasing light that can be extracted outside the device. In order to increase the external light extraction efficiency, the reflectance of the recess side face  19  of the lead  10  is preferably increased by silver plating. In this example again, the side face of the semiconductor light emitting device  50  can be placed close to the recess side face  19  to facilitate heat dissipation via the side face  19 . As a result, a semiconductor light emitting apparatus having excellent heat dissipation and improved reliability can be achieved.  
         [0068]      FIGS. 8A and 8B  are schematic views showing a fourth example of the embodiment of the invention. More specifically,  FIG. 8A  is a cross section thereof and  FIG. 8B  is a partially enlarged cross section thereof.  
         [0069]     In this example, the gap between the light emitting device  50  and the recess sidewall  19  is filled with resin having two-layer structure. These resin layers are composed of photoreflective resin  130  and high thermal conductive resin  140  with fillers dispersed therein. The fillers are selected from materials having high photoreflectance such as titanium oxide or potassium titanate in order to increase the reflectance of the surface of the resin serving as matrix. The fillers are mixed into the resin in the form of powder or particles. While  FIGS. 8A and 8B  show an example in which the photoreflective resin  130  is in contact with the semiconductor light emitting device  50  and the high thermal conductive resin  140  is in contact with the sidewall  19  of the recess, they may be provided vice versa. A multilayer made of three or more layers may also be used. According to this example, light extraction efficiency and heat dissipation can be simultaneously improved.  
         [0070]     In addition, a stress relieving effect is also achieved by dispersing fillers.  
         [0071]      FIG. 9  is a schematic cross section showing a fifth example of the embodiment of the invention.  
         [0072]     In this example again, the semiconductor light emitting device  50  is housed in the recess  18 , and they have a generally identical shape and size. However, their shapes are not exactly identical. More specifically, in order to prevent the decrease of light extraction efficiency due to reflection from the recess sidewall  19 , the recess sidewall  19  is shaped vertically, or beveled so as to expand upward. In this case, more preferably, the sidewall of the recess  18  serves as a reflecting plate. More specifically, the surface of the sidewall  19  can be silver plated, for example, to be highly reflective. As a result, light extraction efficiency can be improved.  
         [0073]     On the other hand, the semiconductor light emitting device  50  is shaped as a truncated pyramid slightly expanding downward. Alternatively, the semiconductor light emitting device  50  may be shaped, for example, as a quadrangular prism, or a combination of a quadrangular prism and a truncated pyramid.  
         [0074]     In this example, a gap occurs between the sidewall of the recess  18  and the semiconductor light emitting device  50 . A large amount of sealing resin  40  interposed in this gap is unfavorable with regard to stress and thermal conduction from the resin  40  as described above with reference to  FIG. 2 . Taking thermal conduction as an example, the resin  40  typically has a thermal conductivity of 0.2 W/m° C., whereas gold (Au) has a thermal conductivity of 315 W/m° C. In order to ensure thermal conductivity comparable to that of gold, the gap between the sidewall of the recess  18  and the semiconductor light emitting device  50  preferably has an upper limit of about 630 micrometers.  
         [0075]     In addition, the gap between the recess sidewall  19  and the light emitting device  50  is preferably filled with a monolayer or laminated structure of high thermal conductive resin and photoreflective resin as described above with reference to  FIGS. 8A and 8B .  
         [0076]      FIG. 10  is a schematic cross section showing a sixth example of the embodiment of the invention.  
         [0077]     The structure of the lead recess  18  in which the light emitting device  50  is die bonded is substantially the same as that shown in  FIGS. 1A and 1B . The first lead  12  having the recess  18  is stacked with the second lead  13  directly below the recess (particularly where the light emitting device is mounted) via thermal conductive insulating resin  150 . The thermal conductive insulating resin  150  may be epoxy-based resin or silicone-based resin.  
         [0078]      FIG. 11  is a schematic view for illustrating heat dissipation in the semiconductor light emitting apparatus of this example. Heat generated in the semiconductor light emitting device  50  is conducted not only through the first lead  12  as shown by arrow A, but also through the second lead  13  as shown by arrow B, and then dissipated outside. In addition, as shown by arrow C, heat dissipation via the high thermal conductive resin  20  is facilitated. Therefore this structure is suitable to a high power light emitting apparatus having high heat generation due to large current driving.  
         [0079]      FIGS. 12A and 12B  are schematic cross sections showing a seventh example of the invention. More specifically,  FIG. 12A  is a schematic cross section that generally shows the example, and  FIG. 12B  is a partially enlarged cross section thereof.  
         [0080]     In this example, a submount (or chip carrier)  110  is provided on a lead  14 . The light emitting device  50  is die bonded to the bottom face of a recess  18  provided in the submount (or chip carrier)  110 , rather than of a recess in the lead. The submount  110 , to which the light emitting device  50  is die bonded in advance, can be bonded to the lead  14  with silver paste or eutectic solder  37 . In this process, characteristics determination can be made upon installing the light emitting device  50  in the submount  110 , and therefore if any failure is found, waste in the subsequent process can be eliminated. The submount  110  may be fabricated from ceramic, diamond, nitride, sapphire, Si, GaP, or SiC.  
         [0081]     As shown in  FIG. 12B , in order to make electrical connection to the electrode on the die bonding side of the light emitting device  50 , the bottom face of the submount recess  18  and the submounting surface to which the lead  14  is bonded, for example, are covered with metallization  112 . The metallization  112  is formed by, for example, Mo—Mn thick film sintering, Ni plating, or gold plating. Note that the light emitting device  50  may be die bonded after the submount  110  is bonded to the lead  14 . The bonding force between the light emitting device  50  and the submount  110  is stronger than that between the light emitting device  50  and the lead  14 . Higher bonding strength is achieved by bonding the submount  110  having a larger contact area to the lead  14  than by bonding the light emitting device  50  directly to the lead. The inner wall surface of the recess of the submount  110  can be smoothed and metallized to achieve high photoreflectance.  
         [0082]      FIGS. 13A and 13B  are schematic views showing an eighth example of the invention. More specifically,  FIG. 13A  is a schematic cross section that generally shows the example, and  FIG. 13B  is a side view thereof.  
         [0083]      FIG. 14  is a schematic perspective view of a semiconductor light emitting apparatus of this example.  
         [0084]     In this example, an insulating substrate  160  is used. The insulating substrate  160  has a recess  18 . Metallization  170  extends from the bottom face of the recess  18  to the lower face of the insulating substrate (which is electrically connected to an electrode formed on a packaging board, not shown) via the side face of the insulating substrate  160 . The semiconductor light emitting device  50  is bonded to the bottom face of the recess  18  with silver paste, or AuSn or other eutectic solder. The electrode on the upper face of the light emitting device  50  is connected to another metallization  180  via a bonding wire  35 . This metallization  180  also extends to the lower face of the insulating substrate  160  for electrical connection to the packaging board, not shown.  
         [0085]     Photoreflective resin  30  with a beveled reflecting surface surrounding the recess  18  is provided on the upper face of the insulating substrate  160 . Part of the light emitted from the light emitting device  50  is reflected by the photoreflective resin  30 , which leads to a higher extraction efficiency. The bonding wire  35  and the light emitting device  50  are sealed with sealing resin  40 . The photoreflective resin  30 , although not necessarily needed, is effective for enhancing light condensation.  
         [0086]     In this example again, advantageously, the side face of the recess  18  can be placed close to the semiconductor light emitting device  50  to relieve stress to the light emitting device  50  due to expansion and contraction of sealing resin. In addition, the smaller the spacing between the side face of the recess  18  and the light emitting device  50 , the higher the stress reduction and heat dissipation effect.  
         [0087]     Moreover, the effect of filling the gap between the recess  18  and the light emitting device  50  with photoreflective resin and/or high thermal conductive resin is as described above with reference to  FIGS. 8A and 8B . The insulating substrate  160  can be made of ceramic, diamond, nitride, sapphire, SiC, GaP, or Si. Among ceramics, AlN, for example, has high thermal conductivity and excellent workability. Therefore an AlN substrate can be used to achieve a compact light emitting apparatus of the surface mount type suitable to large current operation.  
         [0088]      FIG. 15  is a schematic cross section showing a ninth example of the embodiment of the invention. With regard to this figure, elements similar to those described above with reference to  FIGS. 1A  to  14  are marked with the same reference numerals and will not be described in detail.  
         [0089]     In this example again, the semiconductor light emitting device  50  is housed in the recess  18 , and they have a generally identical shape and size. The semiconductor device  50 , like the first example illustrated in  FIGS. 1A and 1B , is shaped as a truncated pyramid expanding upward. Alternatively, the semiconductor light emitting device  50  may be shaped, for example, as a quadrangular prism, or a combination of a quadrangular prism and a truncated pyramid.  
         [0090]     In this example, sealing resin  40  mixed with phosphors  152  is provided above and around the semiconductor light emitting device  50 . Emitted light from the semiconductor light emitting device  50  is absorbed by the phosphors  152 , which is then excited and converts the wavelength to emit light having a longer wavelength. The wavelength associated with the semiconductor light emitting device  50  is preferably in the wavelength band of ultraviolet to blue light. Phosphors absorbing primary light in this wavelength band and emitting secondary light such as red, blue, or yellow light, for example, can be selected. For example, a gallium nitride based semiconductor light emitting device that emits blue light can be selected as the semiconductor light emitting device  50 , and phosphors made of silicate can be selected as the phosphors absorbing the blue light and emitting yellow light. In this way, white light can be obtained as a mixture of the blue and yellow light. In this example again, since the semiconductor light emitting device  50  is placed in the recess  18  having a generally identical shape and size, stress to the semiconductor light emitting device  50  can be relieved.  
         [0091]     In this example, semiconductor device  50  can be placed in the recess  18  after phosphors are applied or deposited around the semiconductor device  50 .  
         [0092]      FIG. 16  is a schematic cross section showing a tenth example of the embodiment of the invention. With regard to this figure again, elements similar to those described above with reference to  FIGS. 1A  to  15  are marked with the same reference numerals and will not be described in detail.  
         [0093]     In this example, a region above the recess  18  in which the semiconductor light emitting device  50  is placed is covered with transparent material  154  having a higher refractive index than the sealing resin  40 . The transparent material  154  is preferably a resin having a smaller linear expansion coefficient than the sealing resin  40 , a resin mixed with fillers to relieve stress, or a low hardness (“soft”) resin such as silicone. Moreover, by shaping the transparent material  154  generally as a hemisphere, the transparent material  154  can be used to serve as a condensing lens. As a result, distribution angle of light emitted outside can be made small, thereby achieving highly convergent directional characteristics.  
         [0094]     Furthermore, phosphors can be mixed with the transparent material  154  for wavelength conversion to obtain white light, for example. In this case, silicone is advantageously used as the transparent material  154  because of no degradation for ultraviolet radiation. More specifically, there may be a problem that upon being exposed to ultraviolet radiation, epoxy resin or the like is gradually discolored and its translucency is decreased. In contrast, according to this embodiment, the transparent material  154  is made of silicone with phosphors dispersed therein so that the wavelength of ultraviolet radiation emitted from the semiconductor light emitting device  50  can be converted into visible light. In this way, degradation of the sealing resin  40  can be prevented even when it is made of epoxy resin.  
         [0095]     Moreover, fillers can be dispersed in the transparent material  154  to enhance reflectance. As with the other examples, it is understood that stress to the semiconductor light emitting device  50  can be relieved because the semiconductor light emitting device  50  and the recess  18  have a generally identical shape and size.  
         [0096]      FIG. 17  is a schematic cross section showing an eleventh example of the embodiment of the invention. With regard to this figure again, elements similar to those described above with reference to  FIGS. 1A  to  16  are marked with the same reference numerals and will not be described in detail.  
         [0097]     In this example, a wider area surrounding the region above the recess  18  in which the semiconductor light emitting device  50  is placed is covered with transparent material  156  having a higher refractive index than the sealing resin  40 . The transparent material  156  is preferably shaped as a hemisphere, or a structure having a curved surface being convex upward. As with the tenth example, phosphors can be mixed in the transparent material  156  to obtain white light and degradation of the sealing resin  40  due to ultraviolet radiation can be prevented. Moreover, fillers can be dispersed in the transparent material  156  to scatter light and obtain uniform white light.  
         [0098]     Moreover, in this example again, the transparent material  156  can be used to serve as a condensing lens, and the reflecting surface  31  of the photoreflective resin  30  can be utilized. As a result, the light distribution angle can be easily controlled, and the directivity becomes more controllable. As with the other examples, it is understood that stress to the semiconductor device  50  can be relieved because the semiconductor light emitting device  50  and the recess  18  have a generally identical shape and size.  
         [0099]     Embodiments of the invention have been described with reference to examples. However, the invention is not limited to these examples.  
         [0100]     For example, the invention is not limited to the use of InGaAlP-based and GaN-based semiconductor light emitting device chips. GaAlAs-based, InP-based, and various other group III-V compound semiconductors, or group II-VI compound semiconductors or various other semiconductors may be used.  
         [0101]     Any shape, size, material, and arrangement of various elements including the semiconductor light emitting device chip, leads, embedding resin, and sealing resin composing the semiconductor light emitting apparatus that are adapted by those skilled in the art are also encompassed within the scope of the invention as long as they include the features of the invention.  
         [0102]     For example, in the example shown in  FIG. 18 , without photoreflective resin  30  as illustrated in  FIGS. 1A and 1B , the upper face of the leads  10  and  11  is covered with sealing resin  40 . In this case, light can be emitted in all directions from the upper face, achieving wide-angle light distribution characteristics.  
         [0103]     In the example shown in  FIG. 19 , each of the leads  10  and  11  are formed straight and the opposed portions are sealed with sealing resin  40 . The structure like this can also be used.  
         [0104]      FIG. 20  is a schematic cross section for supplemental remarks common to the foregoing examples.  
         [0105]     The term “to house” used herein also covers the situation in which the upper face of the semiconductor light emitting device  50  protrudes upward from the opening edge of the recess  18  provided in the first lead. As long as the semiconductor light emitting device  50  is directly affected by the stress due to expansion and contraction of the sealing resin  40 , the semiconductor light emitting device  50  may protrude a vertical distance D from the opening edge of the recess  18 . In this case again, the relation on the stress generated between the semiconductor light emitting device  50  and the sealing resin  40  illustrated in  FIG. 4  is applicable. Therefore the vertical distance D is preferably not larger than 0.1 millimeter.  
         [0106]     Possible combinations of two or more of the examples described above with reference to  FIGS. 1A  to  20  are also encompassed within the scope of the invention.