JP2007299811A - Stem for light-emitting element, semiconductor light-emitting device, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stem for light-emitting elements capable of reducing manufacturing costs, and to provide a semiconductor light-emitting device and a method of manufacturing the light-emitting device. <P>SOLUTION: The semiconductor light-emitting device comprises: a conductive heat sink 10 having a mounting surface 14 that is provided in contact with a base 30 and is sandwiched between protection walls 12; a step surface 16 provided between the mounting surface 14 and the top of the protection wall 12; a subcarrier 20 mounted onto the mounting surface 14; a semiconductor light-emitting element 22 to which the subcarrier 20 is mounted; and a wire 24 for connecting the semiconductor light-emitting element 22 to the step surface 16 electrically. The method for manufacturing the semiconductor light-emitting device and the stem for light-emitting elements are provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light emitting element stem, a semiconductor light emitting device, and a method for manufacturing the same, and more particularly, to a light emitting element stem including a heat sink having a mounting surface sandwiched between protective walls, a semiconductor light emitting device, and a method for manufacturing the same. It relates to a manufacturing method.

  Semiconductor light emitting devices such as semiconductor lasers and LEDs are used for so-called home appliances used in general households such as optical disk light sources. Such home appliances are required to be reduced in price. A semiconductor light emitting device is used by mounting a semiconductor light emitting element, which is a chip such as a semiconductor laser, on a stem. In order to reduce the price, for example, a semiconductor light emitting device that is capless, that is, does not perform hermetic sealing is also used. In a capless semiconductor light emitting device, a semiconductor light emitting element mounted on a stem and a wire connecting the semiconductor element and the stem are exposed to the outside air. For this reason, when the semiconductor light emitting device is transported or assembled into a home appliance, the semiconductor light emitting element or the wire may be damaged by an external force.

  FIG. 3 of Patent Document 1 discloses a semiconductor light emitting device in which a groove is formed in the heat sink 4 and the subcarrier 3 and the semiconductor light emitting element 1 are mounted on the bottom surface of the groove. That is, the heat sink 4 has two protective walls, and the subcarrier 3 is mounted on the mounting surface sandwiched between the protective walls, and the semiconductor light emitting element 1 is mounted on the subcarrier 3. According to such a structure, since the protective wall of the heat sink 4 protects the semiconductor light emitting element or the wire, the semiconductor light emitting element or the wire can be prevented from being damaged.

  In general, in a semiconductor light emitting device, a semiconductor layer is formed on an N-type conductive semiconductor substrate. By applying a voltage between the uppermost P-type semiconductor layer and the N-type conductive semiconductor substrate among the semiconductor layers, light (for example, laser light) is output from the vicinity of the active layer in the semiconductor layer. The voltage is applied by grounding the N-type semiconductor substrate side as a reference potential and applying a positive voltage to the P-type semiconductor layer. In Patent Document 1, the voltage is applied to the upper surface of the semiconductor light emitting element from the terminal 7a through the wire 6 on the one hand. On the other hand, a voltage is applied from the terminal 7 b to the lower surface of the semiconductor element 1 through the stem 5, the heat sink 4 and the subcarrier 3.

There are two types of semiconductor light emitting devices, a junction down type and a junction up type. The junction up type is a type in which the semiconductor substrate side of the semiconductor light emitting element is mounted on the subcarrier, and the junction down type is a type in which the semiconductor layer side of the semiconductor light emitting element is mounted on the subcarrier. Since the semiconductor light emitting device outputs light near the active layer in the semiconductor layer, the vicinity of the active layer generates the most heat. Therefore, the junction down type in which the semiconductor layer side is mounted on the subcarrier can efficiently dissipate the heat generated near the active layer from the subcarrier.
Japanese Utility Model Publication No. 62-8655

  However, applying the same mounting method as in Patent Document 1 to a semiconductor light emitting device mounted in, for example, a junction down type has the following problems. In FIG. 3 of Patent Document 1, the lower surface of the semiconductor light emitting element is electrically connected to the terminal 7 b through the conductive subcarrier 3. Therefore, when the junction down type is mounted, the semiconductor layer side to which a positive voltage is applied is mounted on the subcarrier 3. Therefore, the heat sink 4 and the stem 5 electrically connected to the subcarrier 3 also have a positive potential.

  In order to avoid this, there is a structure as shown in FIG. Referring to FIG. 1, the heat sink 10 has a protective wall 12. An insulating subcarrier 20 is mounted on a mounting surface 14 sandwiched between the protective walls 12, and a semiconductor light emitting element 22 is mounted on a metal film 21 of the subcarrier 20. Has been. A wire 24 is provided to connect to the mounting surface 14 from the upper surface of the semiconductor light emitting element 22 (that is, the semiconductor substrate side of the semiconductor light emitting element). A wire 26 connected to the lead 32 insulated from the metal film 21 on the upper surface of the subcarrier 20 by the insulating portion 33 from the base 30 is provided. In this way, the subcarrier 20 is made insulative, and the upper surface (semiconductor substrate side, that is, the side to be set as the reference potential) of the semiconductor light emitting element 22 is connected to the mounting surface 14. Thereby, the heat sink 10 and the base 30 are grounded. On the other hand, the lower surface of the semiconductor light emitting element 22 (that is, the semiconductor layer side of the semiconductor light emitting element) is connected to the lead 32 via the metal film 21 and the wire on the upper surface of the subcarrier 20.

  When mounting the semiconductor light emitting device having the structure of FIG. 1, it is necessary to wire bond the upper surface of the semiconductor light emitting element 22 and the mounting surface 14. Some bonding devices for wire bonding can change the wire bonding surface. However, since such a bonding device is expensive, in order to manufacture an inexpensive semiconductor light emitting device, the wire bonding surface must be changed. Use a bonding device that cannot be changed. For this reason, the wire bonding bonding tool moves between the upper surface of the semiconductor light emitting element 22 and the mounting surface 14 to perform wire bonding. When wire bonding with a long moving distance is performed automatically for a long time, the drive unit of the bonding tool is displaced, and bonding is performed outside the region to be bonded to damage the chip. This may cause a decrease in yield due to in-process defects and a decrease in reliability after shipment. Also, the bonding tool may jam. In order to prevent this, if maintenance is frequently performed, the operating rate of the bonding apparatus is lowered, and the manufacturing cost is increased. Furthermore, a wire made of gold, in particular, tends to hang down, and the wire 24 may come into contact with the metal film 21 and cause a short circuit.

  The above has described the problems of the prior art by taking a junction down type semiconductor light emitting device as an example. The junction-up type semiconductor light emitting device may be wire-bonded from the upper surface of the subcarrier to the mounting surface in response to a request to make the subcarrier insulative. In this case, there is the same problem as described with the junction down type as an example.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a stem for a light-emitting element, a semiconductor light-emitting device, and a method for manufacturing the same that can reduce manufacturing costs.

  The present invention is provided in contact with a base, and is provided between a conductive heat sink having a mounting surface for mounting a subcarrier sandwiched between protective walls, and between the mounting surface and the top of the protective wall. A stem for a light-emitting element, comprising a step surface for connecting wires. By manufacturing a semiconductor light emitting device using the light emitting element stem of the present invention, it is possible to reduce the manufacturing cost when forming a wire connecting the step surface and the semiconductor light emitting element.

  The said structure WHEREIN: The said mounting surface can be set as the structure provided below the center of the said base. According to this configuration, for example, the light emitting region of the semiconductor light emitting element can be set as the center of the stem.

  The said structure WHEREIN: The width | variety of the direction between the said protective walls of the said mounting surface can be set as a structure narrower than the space | interval of the said protective walls above the said step surface.

  The said structure WHEREIN: The said base and the said step surface can be set as the structure electrically connected.

  The present invention is provided in contact with a base, and is provided between a conductive heat sink having a mounting surface for mounting a subcarrier sandwiched between protective walls, and between the mounting surface and the top of the protective wall. A step surface, a subcarrier mounted on the mounting surface, a semiconductor light emitting device mounted on the subcarrier, and a wire electrically connecting the semiconductor light emitting device and the step surface; can do. According to the present invention, it is possible to reduce the manufacturing cost when forming the wire connecting the step surface and the semiconductor light emitting element.

  The said structure WHEREIN: The said wire can be set as the structure connected with the upper surface of the said semiconductor light-emitting device. Moreover, the said structure WHEREIN: The said wire can be set as the structure connected with the said semiconductor light-emitting element by connecting with the upper surface of the said subcarrier. Furthermore, the step surface and the base may be electrically connected.

  The present invention provides a semiconductor light emitting device on a subcarrier in a step of mounting a subcarrier on a mounting surface sandwiched between protective walls of a conductive heat sink and a step before or after the step of mounting the subcarrier. And a step of forming a wire for electrically connecting the semiconductor light emitting element and a step surface provided between the mounting surface and the top of the protective wall. A method for manufacturing a semiconductor light emitting device. According to the present invention, it is possible to reduce the manufacturing cost when forming the wire connecting the step surface and the semiconductor light emitting element.

  In the above configuration, the step of forming the wire may include a step of forming a wire that electrically connects the semiconductor light emitting element and the step surface. In the above configuration, the step of forming the wire may include a step of forming a wire that electrically connects the upper surface of the subcarrier and the step surface.

  The said structure WHEREIN: It can be set as the structure which has the process of forming the wire which electrically connects the lead provided in the position higher than the said step surface, and the said semiconductor light-emitting element after the process of forming the said wire. According to this structure, the contact of a wire can be prevented.

  ADVANTAGE OF THE INVENTION According to this invention, the stem for light emitting elements which can reduce manufacturing cost, a semiconductor light-emitting device, and its manufacturing method can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

  Example 1 is an example of a stem for a light emitting element. FIG. 2A is a front view of the stem for a light emitting element according to Example 1, and FIG. 2B is a side view. In the first to third embodiments, the heat sink 10 side is referred to as a downward direction with respect to the mounting surface 14, and the spatial direction with respect to the mounting surface 14 is referred to as an upward direction. That is, when the semiconductor light emitting element 22 is mounted, the direction from the semiconductor light emitting element 22 to the mounting surface 14 is downward, and the direction from the mounting surface 14 to the semiconductor light emitting element 22 is upward. The light emitting element stem 34 includes a base 30, a heat sink 10 provided in contact with the base 30, and leads 32 and 36. Referring to FIG. 2A, the heat sink 10 has two protective walls 12 on both sides, and has a mounting surface 14 for mounting the subcarrier 20 sandwiched between the protective walls 12. In other words, the heat sink 10 has a groove, both sides of the groove are the protective walls 12, and the bottom surface of the groove is the mounting surface 14. Similarly to the structure of FIG. 3 of Patent Document 1, the protective wall 12 has a function of protecting the semiconductor light emitting element or the wire and suppressing the damage of the semiconductor light emitting element or the wire.

  The heat sink 10 has a step surface 16 to which a wire is to be connected. The step surface 16 is higher than the mounting surface 14 and lower than the top (upper surface) of the protective wall 12. That is, it is provided between the mounting surface 14 and the top of the protective wall 12. Since the step surface 16 and the mounting surface 14 are formed stepwise, the width W1 of the mounting surface 14 in the direction of the protective wall 12 is formed narrower than the interval W2 of the protective wall 12 above the step surface 16. Further, the mounting surface 14 can be provided below the center C of the base 30.

  Referring to FIG. 2B, the lead 32 is electrically separated from the base 30 through the insulating portion 33, and penetrates from the back surface side of the base 30 to the front surface side (the right side to the left side in FIG. 2B). is doing. The lead 36 is connected to the base 30 and is electrically connected to the step surface 16 via the base 30.

  The base 30 and the heat sink 10 can be processed by squeezing from a conductive plate made of copper, for example, and the base 30 and the heat sink 10 can be integrally processed. The base 30 and the heat sink 10 can also be formed by cutting or MIM (powder forming method). In addition to copper, the base 30 and the heat sink 10 can be made of a conductive material such as iron or a non-conductive material coated with a conductive film. In order to reduce the manufacturing cost, an inexpensive material is preferable, and in the case where heat dissipation is important, a material excellent in heat dissipation is preferable. Further, although one step surface 16 is provided, two or more step surfaces 16 may be provided in order to improve the heat dissipation of the heat sink 10. Furthermore, the step surface 16 may not be the surface of the heat sink 10 but may be a surface formed on another member. Further, the heat sink 10 and the base 30 may be separately formed and fixed. Furthermore, although the base 30 has a cylindrical shape and the heat sink 10 has a cylindrical shape having grooves, the shape is not limited to this.

  The heat sink 10 has a diameter (a lateral width of the heat sink 10 in FIG. 2A) of, for example, about 3.0 mm and a length (in the depth direction of FIG. 2A) of, for example, 2.8 mm. The mounting surface 14 has a width (lateral width in FIG. 2A) of, for example, 0.2 to 1.5 mm and a length (depth method of FIG. 2A) of, for example, about 0.35 mm. The length of the step surface 16 (in the depth direction in FIG. 2A) is, for example, 0.05 to 0.5 mm. These dimensions can be appropriately changed as long as the respective members and surfaces exhibit their functions.

  Example 2 is an example of a semiconductor light emitting device mounted in a junction down type. A method for manufacturing the semiconductor light emitting device according to the second embodiment will be described with reference to FIGS. Referring to FIG. 3A, the light emitting element stem 34 according to the first embodiment is used, and the semiconductor light emitting element 22 is mounted on the metal film 21 on the insulating subcarrier 20 by using, for example, AuSn. The semiconductor light emitting element 22 is mounted on the metal film 21 on the semiconductor layer side. The subcarrier 20 is mounted on the mounting surface 14 using, for example, AuSn. At this time, it is preferable to mount so that the center C of the base 30 becomes the light output region of the semiconductor light emitting element 22. The subcarrier 20 is made of, for example, a semiconductor or an insulator such as silicon, aluminum nitride, silicon carbide, or diamond, and a material having high thermal conductivity is preferable. The subcarrier 20 has a width (width in the lateral direction of FIG. 3A) of, for example, 0.15 to 1.451 mm, and a length (depth direction of FIG. 3A) of, for example, 0.3 to 3. 3 mm. The semiconductor light emitting element 22 has a width (lateral width in FIG. 3A) of, for example, 0.2 mm and a length (depth direction of FIG. 3A) of, for example, 2.2 mm. These dimensions can be appropriately changed as long as each member exhibits its function. Alternatively, the subcarrier 20 may be mounted on the mounting surface 14 and then the semiconductor light emitting element 22 may be mounted on the subcarrier 20.

  Referring to FIG. 3B, a wire 24 that electrically connects the upper surface of the semiconductor light emitting element 22 (that is, the surface serving as the reference potential on the semiconductor substrate side) and the step surface 16 is formed. As shown in FIG. 3C, the base 30 is provided with a lead 32 that is electrically separated by the base 30 and the insulating portion 33 at a position higher than the step surface 16. A wire 26 for electrically connecting the metal film 21 of the subcarrier 20 to which the semiconductor light emitting element 22 is fixed and the lead 32 is formed. Thereby, the wire 26 electrically connects the lower surface of the semiconductor light emitting element 22 (that is, the surface on the semiconductor layer side) and the lead 32. The diameter of the wires 26 and 26 is, for example, 0.025 mm, and the material can be a metal such as gold or aluminum. Thus, the semiconductor light emitting device is completed.

  The semiconductor light emitting device according to the second embodiment uses the semiconductor light emitting element stem 34 according to the first embodiment in which the step surface 16 to which the wire 24 is connected is provided between the mounting surface 14 and the top of the protective wall 12. . Thereby, the moving distance of the bonding tool can be shortened. Therefore, manufacturing cost can be reduced. Further, contact between the wire 24 and the metal film 21 can be prevented. In order to shorten the moving distance of the bonding tool, the step surface 16 is preferably as high as the upper surface of the semiconductor light emitting element 22 to which the wire 24 is connected.

  The semiconductor light emitting device may be required to have the light emitting region at the center of the base 30. In this case, by providing the mounting surface 14 below the center of the base 30, the light emitting region of the semiconductor light emitting element 22 can be set as the center of the base 30.

  Further, in the semiconductor light emitting element stem 34 according to Example 1, the width W1 of the mounting surface 14 in the direction between the protective walls 12 is larger than the interval W2 of the protective walls 12 above the step surface 16, as shown in FIG. narrow. In this way, the step surface 16 can be provided between the mounting surface 14 and the top of the protective wall 12.

  Further, the step surface 16 and the base 30 are electrically connected. Thereby, when the semiconductor substrate side to be the reference potential of the semiconductor light emitting element 22 is connected to the step surface 16, the semiconductor substrate side can be set to the potential of the base 30. That is, it can be grounded.

  Further, when the semiconductor light emitting device is manufactured, as shown in FIG. 3B, after forming the wire 24 that electrically connects the upper surface of the semiconductor light emitting element 22 and the step surface 16, as shown in FIG. Thus, it is preferable to form the wire 26 that electrically connects the lead 32 provided at a position higher than the step surface 16 and the lower surface of the semiconductor light emitting element 22. In many cases, the lower surface of the semiconductor light emitting element 22 (surface having a potential other than the reference potential) is connected to a lead positioned higher than the step surface 16. For this reason, the wire 26 that electrically connects the semiconductor light emitting element 22 and the lead 32 has a larger wire loop than the wire 24 that connects the semiconductor light emitting element 22 and the step surface 16. It is preferable to perform wire bonding from the one having a small diameter in order to prevent contact of the wires. Therefore, it is preferable to form the wires 24 and 26 in the order shown in FIGS. 3 (b) and 3 (c).

  In addition, although the lead 32 of the present embodiment is provided at a position higher than the step surface 16, it is not limited to this. For example, it is possible to provide the same height as the center of the base 30. In this case, a groove may be provided in the heat sink 10 below the lead 32 and the insulating portion 33 so as not to hinder the arrangement of the lead 32 and the insulating portion 33.

  Example 3 is an example of a semiconductor light emitting device mounted in a junction-up type. Contrary to FIG. 3A, the semiconductor substrate side of the semiconductor light emitting element 22 is mounted on the metal film 21 on the subcarrier 20. Referring to FIG. 4A, the wire 25 for electrically connecting the metal film 21 of the subcarrier 20 to which the semiconductor light emitting element 22 is fixed and the step surface 16 is formed using the light emitting element stem 34 of the first embodiment. To do. Thereby, the wire 25 electrically connects the lower surface of the semiconductor light emitting element 22 (that is, the surface serving as the reference potential on the semiconductor substrate side) and the step surface 16. Referring to FIG. 4B, a wire 27 that electrically connects the upper surface of the semiconductor light emitting element 22 (that is, the surface on the semiconductor layer side of the semiconductor light emitting element) and the lead 32 is formed. Thus, the semiconductor light emitting device according to Example 3 is completed.

  In the second embodiment, the upper surface of the semiconductor light emitting element 22 and the step surface 16 can be wire-bonded, and the upper surface of the subcarrier 20 and the lead 32 can be wire-bonded. Thereby, the upper surface of the semiconductor light emitting element 22 is electrically connected to the lead 36 electrically connected to the base 30 via the step surface 16. Further, the lower surface of the semiconductor light emitting element 22 is electrically connected to a lead 32 that is electrically separated from the base 30 via the metal film 21 on the upper surface of the subcarrier 20.

  On the other hand, in Example 3, the upper surface of the subcarrier 20 and the step surface 16 can be wire-bonded, and the upper surface of the semiconductor light emitting element 22 and the lead 32 can be wire-bonded. Accordingly, the upper surface of the semiconductor light emitting element 22 is electrically connected to the lead 32 that is electrically separated from the base 30. Further, the lower surface of the semiconductor light emitting element 22 is electrically connected to the lead 36 electrically connected to the base 30 through the step surface 16. As described above, the present invention can be applied to a junction down type mounting or a junction down type mounting.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

FIG. 1 is a front view of a conventional semiconductor light emitting device. FIG. 2A and FIG. 2B are a front view and a side view of the stem for the light emitting element according to the first embodiment. FIG. 3A to FIG. 3C are front views illustrating the method for manufacturing the semiconductor light emitting device according to the second embodiment. 4A and 4B are front views illustrating the method for manufacturing the semiconductor light emitting device according to the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Heat sink 12 Protective wall 14 Mounting surface 16 Step surface 20 Subcarrier 21 Metal film 22 Semiconductor light emitting element 24, 25, 26, 27 Wire 30 Base 32 Lead 33 Insulating part 34 Stem

Claims (12)

A conductive heat sink having a mounting surface for mounting a subcarrier provided in contact with the base and sandwiched between protective walls;
A stem for a light emitting device, comprising: a step surface for connecting a wire provided between the mounting surface and the top of the protective wall.   The light emitting element stem according to claim 1, wherein the mounting surface is provided below a center of the base.   The stem for a light emitting element according to claim 1, wherein a width of the mounting surface in the direction between the protective walls is narrower than an interval between the protective walls above the step surface.   The light emitting element stem according to claim 1, wherein the step surface and the base are electrically connected. A conductive heat sink having a mounting surface for mounting a subcarrier provided in contact with the base and sandwiched between protective walls;
A step surface provided between the mounting surface and the top of the protective wall;
A subcarrier mounted on the mounting surface;
A semiconductor light emitting device mounted on the subcarrier;
A semiconductor light emitting device comprising: a wire for electrically connecting the semiconductor light emitting element and the step surface.   The semiconductor light emitting device according to claim 5, wherein the wire is connected to an upper surface of the semiconductor light emitting element.   6. The semiconductor light emitting device according to claim 5, wherein the wire is connected to the semiconductor light emitting element by being connected to an upper surface of the subcarrier.   The semiconductor light emitting device according to claim 5, wherein the step surface and the base are electrically connected. Mounting the subcarrier on the mounting surface sandwiched between the protective walls of the conductive heat sink;
A step of mounting a semiconductor light emitting element on the subcarrier in a step before or after the step of mounting the subcarrier;
A step of forming a wire for electrically connecting the semiconductor light emitting element and a step surface provided between the mounting surface and a top portion of the protective wall. Production method.   The method for manufacturing a semiconductor light emitting device according to claim 9, wherein the step of forming the wire includes a step of forming a wire for electrically connecting the semiconductor light emitting element and the step surface.   10. The method of manufacturing a semiconductor light emitting device according to claim 9, wherein the step of forming the wire includes a step of forming a wire that electrically connects the upper surface of the subcarrier and the step surface. 10. The semiconductor according to claim 9, further comprising a step of forming a wire for electrically connecting a lead provided at a position higher than the step surface and the semiconductor light emitting element after the step of forming the wire. Manufacturing method of light-emitting device.

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