Surface-emitting laser module and method for manufacturing the same

Abstract

This invention relates to a surface-emitting laser module and its manufacturing method. A portion of the upper surface of a surface-emitting laser chip (1) is a light-emitting surface (2). Electrodes (4) are disposed on the upper surface of the surface-emitting laser chip (1) in a manner surrounding the light-emitting surface (2). A lead frame (6) has an opening (6a) disposed opposite to the light-emitting surface (2) and a junction (6b) disposed around the opening (6a). A bonding material (7) bonds the electrodes (4) to the junction (6b). A through hole (6c) through the lead frame (6) is disposed in the junction (6b).

Description

Technical Field

[0001] This disclosure relates to a surface-emitting laser module and a method for manufacturing the same. Background Technology

[0002] A surface-emitting laser chip emits light in a vertical direction from its light-emitting surface (see, for example, Patent Document 1). Conventionally, wire bonding was used when electrical wiring was implemented on the light-emitting surface side of the surface-emitting laser chip. In recent years, the use of lead frames has been studied to improve product availability.

[0003] Patent Document 1: Japanese Patent Application Publication No. 11-266058

[0004] When a leadframe is bonded to multiple chips via bonding material, the distance between each chip and the leadframe will vary. This results in the following problem: in chips closer to the leadframe, crushed bonding material may leak onto the light-emitting surface, obstructing it. Summary of the Invention

[0005] This disclosure is made to solve the aforementioned problems, and its purpose is to obtain a surface-emitting laser module and a method thereof capable of preventing bonding material from flowing out of the light-emitting surface.

[0006] The surface-emitting laser module disclosed herein is characterized by comprising: a surface-emitting laser chip, a portion of which is a light-emitting surface; an electrode disposed on the upper surface of the surface-emitting laser chip in a manner surrounding the light-emitting surface; a lead frame having an opening disposed at a position opposite to the light-emitting surface and a joint portion disposed around the opening; and a bonding material for bonding the electrode to the joint portion, wherein a through hole through the lead frame is disposed in the joint portion.

[0007] In this disclosure, a through hole is provided at the joint of the lead frame. Excess bonding material flows into the narrow through hole due to capillary action, thus preventing bonding material from flowing out to the light exit surface. Attached Figure Description

[0008] Figure 1 This is a top view showing the surface-emitting laser chip of Embodiment 1.

[0009] Figure 2 This is a cross-sectional view showing the surface-emitting laser chip of Embodiment 1.

[0010] Figure 3 This is a top view showing the surface-emitting laser module of Embodiment 1.

[0011] Figure 4 This is a cross-sectional view showing the surface-emitting laser module of Embodiment 1.

[0012] Figure 5 This is a cross-sectional view showing the manufacturing process of the surface-emitting laser module of Embodiment 1.

[0013] Figure 6 This is a cross-sectional view showing the manufacturing process of the surface-emitting laser module of Embodiment 1.

[0014] Figure 7 This is a cross-sectional view showing the manufacturing process of the surface-emitting laser module of Embodiment 1.

[0015] Figure 8 This is a cross-sectional view showing a modified example of the manufacturing process of the surface-emitting laser module of Embodiment 1.

[0016] Figure 9 This is a cross-sectional view showing a modified example of the manufacturing process of the surface-emitting laser module of Embodiment 1.

[0017] Figure 10 This is a cross-sectional view showing a modified example of the manufacturing process of the surface-emitting laser module of Embodiment 1.

[0018] Figure 11 This is a top view of a modified example 1 of the surface-emitting laser chip according to embodiment 1.

[0019] Figure 12 This is a cross-sectional view showing a modified example 1 of the surface-emitting laser chip of embodiment 1.

[0020] Figure 13 This is a top view showing a modified example 1 of the surface-emitting laser module of embodiment 1.

[0021] Figure 14 This is a cross-sectional view showing a modified example 1 of the surface-emitting laser module of embodiment 1.

[0022] Figure 15 This is a cross-sectional view showing a modified example 2 of the surface-emitting laser module of embodiment 1.

[0023] Figure 16 This is a top view showing the surface-emitting laser module of Embodiment 2.

[0024] Figure 17 This is a cross-sectional view showing the surface-emitting laser module of Embodiment 3.

[0025] Figure 18 This is a cross-sectional view showing the surface-emitting laser module of embodiment 4.

[0026] Figure 19 This is a cross-sectional view showing the surface-emitting laser module of Embodiment 5.

[0027] Figure 20 This is a top view showing the surface-emitting laser module of embodiment 6.

[0028] Figure 21 This is a cross-sectional view showing the surface-emitting laser module of Embodiment 6.

[0029] Figure 22 This is a top view showing the surface-emitting laser chip of Embodiment 7.

[0030] Figure 23 This is a cross-sectional view showing the surface-emitting laser chip of Embodiment 7.

[0031] Figure 24 This is a cross-sectional view showing the surface-emitting laser module of Embodiment 7. Detailed Implementation

[0032] The surface-emitting laser module of the embodiment and its manufacturing method are described with reference to the accompanying drawings. The same or corresponding components are labeled with the same reference numerals, and sometimes repeated descriptions are omitted.

[0033] Implementation method 1.

[0034] Figure 1 This is a top view showing the surface-emitting laser chip of Embodiment 1. Figure 2 This is a cross-sectional view showing the surface-emitting laser chip of Embodiment 1. The surface-emitting laser chip 1 has: a semiconductor substrate 1a of a first conductivity type, an active layer 1b thereon, and a semiconductor layer 1c of a second conductivity type. For example, the first conductivity type is n-type, and the second conductivity type is p-type.

[0035] A portion of the upper surface of the surface-emitting laser chip 1 is a light-emitting surface 2. The light-emitting surface 2 is covered by an insulating film 3. Electrodes 4 are disposed on the upper surface of the surface-emitting laser chip 1 in a manner surrounding the light-emitting surface 2. Electrodes 5 are disposed on the lower surface of the surface-emitting laser chip 1. If a voltage is applied between electrodes 4 and 5, light is generated in the active layer 1b. The generated light is emitted from the light-emitting surface 2 in a direction perpendicular to the upper surface of the surface-emitting laser chip 1.

[0036] Figure 3 This is a top view showing the surface-emitting laser module of Embodiment 1. Figure 4 This is a cross-sectional view showing the surface-emitting laser module of Embodiment 1. The lead frame 6 has an opening 6a located opposite the light-emitting surface 2, and a bonding portion 6b surrounding the opening 6a. A bonding material 7 bonds the upper surface of the electrode 4 of the surface-emitting laser chip 1 to the lower surface of the bonding portion 6b of the lead frame 6. The lead frame 6 is made of a metal such as copper. The bonding material 7 is, for example, solder.

[0037] A through hole 6c, extending vertically through the lead frame 6, is provided at the joint portion 6b of the lead frame 6. Viewed from above, multiple small circular through holes 6c are arranged to surround the opening 6a. A portion of the bonding material 7 flows into the through hole 6c.

[0038] Next, the manufacturing method of the surface-emitting laser module of this embodiment will be described. Figures 5-7 This is a cross-sectional view showing the manufacturing process of the surface-emitting laser module according to Embodiment 1. First, an electrode 4 is formed on the upper surface of the surface-emitting laser chip 1 in such a way that it surrounds the light-emitting surface 2 of the surface-emitting laser chip 1. An opening 6a is formed in the lead frame 6, and a through hole 6c is formed in the joint 6b around the opening 6a, through which the lead frame 6 passes vertically.

[0039] Next, as Figure 5 As shown, bonding material 7 is coated onto electrode 4. Then, as... Figure 6 As shown, the opening 6a of the lead frame 6 is positioned opposite the light emitting surface 2 of the surface-emitting laser chip 1, and the bonding portion 6b of the lead frame 6 is placed on the bonding material 7. Next, as... Figure 7 As shown, the bonding material 7 is melted by heating, and the electrode 4 is bonded to the bonding portion 6b using the molten bonding material 7. At this time, the light emitting surface 2 side becomes a wider space due to the opening 6a, while the through hole 6c is a narrow space. Therefore, excess bonding material 7 flows into the narrow through hole 6c due to capillary action and does not flow out to the light emitting surface 2. Especially when the bonding material 7 is solder, it flows into the through hole 6c more easily than wetting and spreading on the poorly wettable insulating film 3.

[0040] Next, a variation of the manufacturing method of the surface-emitting laser module of this embodiment will be described. Figures 8-10 This is a cross-sectional view showing a modified example of the manufacturing process of the surface-emitting laser module according to Embodiment 1. First, as described above, an electrode 4 is formed on the upper surface of the surface-emitting laser chip 1, and an opening 6a and a through hole 6c are formed in the lead frame 6.

[0041] Next, as Figure 8 As shown, the opening 6a of the lead frame 6 is positioned opposite the light emitting surface 2 of the surface-emitting laser chip 1, and the junction 6b is positioned above the electrode 4 without contacting it. Next, as... Figure 9 As shown, bonding material 7 is coated onto the joint 6b of the lead frame 6. Next, as... Figure 10As shown, the bonding material 7 is melted by heating, and the electrode 4 is bonded to the junction 6b by the molten bonding material 7 passing through the through hole 6c. At this time, only the required amount of bonding material 7 on the lead frame 6 passes through the through hole 6c and expands on the electrode 4 side, so it does not flow out to the light emission surface 2.

[0042] As explained above, in this embodiment, a through hole 6c is provided in the joint portion 6b of the lead frame 6. Excess bonding material 7 flows into the narrow through hole 6c due to capillary action, thus preventing the bonding material 7 from flowing out to the light emission surface 2. As a result, the bonding material 7 does not obstruct the light emission surface 2, and the lead frame 6 can be bonded to the electrode 4 of the surface-emitting laser chip 1.

[0043] Alternatively, the lead frame 6 can be bonded to the electrodes 4 of multiple surface-emitting laser chips 1. In this case, the height deviation of the surface-emitting laser chip 1 can be absorbed by the bonding material 7. Furthermore, by using the lead frame 6, the wire bonding process can be reduced, thus shortening the production cycle. Moreover, heat dissipation can also be achieved from the upper surface side of the surface-emitting laser chip 1 through the lead frame 6.

[0044] Figure 11 This is a top view of a modified example 1 of the surface-emitting laser chip according to embodiment 1. Figure 12 This is a cross-sectional view showing a modified example 1 of the surface-emitting laser chip according to embodiment 1. In addition to electrodes 4, electrodes 5 are also provided on the upper surface of the surface-emitting laser chip 1.

[0045] Figure 13 This is a top view showing a modified example 1 of the surface-emitting laser module of embodiment 1. Figure 14 This is a cross-sectional view showing a modified example 1 of the surface-emitting laser module according to Embodiment 1. The lead frame 6 is bonded to the electrode 4, and the lead frame 6' is bonded to the electrode 5. A through hole 6c is also provided at the bonding portion of the lead frame 6', similar to that of the lead frame 6. Therefore, the bonding material 7 can be prevented from flowing out of the light-emitting surface 2 within the lead frame 6'.

[0046] Figure 15 This is a cross-sectional view showing a modified example 2 of the surface-emitting laser module of Embodiment 1. The surface-emitting laser chip 1 and the lead frame 6 are sealed with molding resin 8. The molding resin 8 covers the upper surface of the joint 6b. A portion of the molding resin 8 flows into the through hole 6c from the upper surface side of the joint 6b. This prevents the molding resin 8 from peeling off.

[0047] The electrode 5 on the lower surface of the surface-emitting laser module is bonded with wiring 10 of the insulating substrate 9. Alternatively, an auxiliary support or heat sink may be bonded instead of the insulating substrate 9. In addition, although the lower surface of the electrode 5 is coplanar with the lower surface of the molding resin 8, the electrode 5 may also protrude from the lower surface of the molding resin 8.

[0048] Implementation method 2.

[0049] Figure 16 This is a top view of the surface-emitting laser module of Embodiment 2. The opening 6a is quadrilateral when viewed from above. The through-hole 6c extends linearly along the outer periphery of each side of the opening 6a when viewed from above. While the small circular through-hole 6c of Embodiment 1 allows the bonding material 7 to easily flow in due to capillary action, the amount of bonding material 7 that can be accommodated is relatively small. In contrast, the linear through-hole 6c of this embodiment can accommodate more bonding material 7. Therefore, adjusting the amount of bonding material 7 applied becomes easier. Other structures and effects are the same as in Embodiment 1.

[0050] Implementation method 3.

[0051] Figure 17 This is a cross-sectional view showing the surface-emitting laser module of Embodiment 3. The through-hole 6c is a positively conical shape that widens from the lower surface side of the lead frame 6 toward the upper surface side. Therefore, the through-hole 6c tapers below where the bonding material 7 is present. Here, the rise of the liquid level due to capillary action is inversely proportional to the radius of the tube. Therefore, compared to Embodiment 1, the rise of the bonding material 7 toward the through-hole 6c becomes significant. Other structures and effects are the same as in Embodiment 1.

[0052] Implementation method 4.

[0053] Figure 18 This is a cross-sectional view showing the surface-emitting laser module of Embodiment 4. The through-hole 6c has an inverted conical shape that narrows from the lower surface side of the lead frame 6 toward the upper surface side. Therefore, the through-hole 6c widens below where the bonding material 7 is present, thus facilitating the entry of the bonding material 7 into the interior of the through-hole 6c. However, if the through-hole 6c is too wide, the climbing of the bonding material 7 into the through-hole 6c becomes weaker. Other structures and effects are the same as in Embodiment 1.

[0054] Implementation method 5.

[0055] Figure 19This is a cross-sectional view showing the surface-emitting laser module of Embodiment 5. A protrusion 11 is provided on the lower surface of the lead frame 6 between the opening 6a and the joining portion 6b. Since the protrusion 11 blocks the joining material 7, it prevents the joining material 7 from flowing out to the light-emitting surface 2. Furthermore, the protrusion 11 is in the shape of a quadrilateral frame surrounding the entire opening 6a, but it can be deformed according to the shape of the light-emitting surface 2 or the lead frame 6 as long as it prevents the joining material 7 from flowing out to the light-emitting surface 2. Other structures and effects are the same as in Embodiment 1.

[0056] Implementation method 6.

[0057] Figure 20 This is a top view showing the surface-emitting laser module of embodiment 6. Figure 21 This is a cross-sectional view showing the surface-emitting laser module of Embodiment 6. A comb structure 12 is provided on the side wall of the opening 6a of the lead frame 6. The comb structure 12 is made of the same material as the lead frame 6. The comb structure 12 attracts the bonding material 7 through capillary action, so a portion of the bonding material 7 is contained in the comb structure 12 to form a solder joint 13. This prevents the bonding material 7 from flowing out to the light emission surface 2. The other structures and effects are the same as in Embodiment 1.

[0058] Implementation method 7.

[0059] Figure 22 This is a top view showing the surface-emitting laser chip of Embodiment 7. Figure 23 This is a cross-sectional view showing the surface-emitting laser chip of Embodiment 7. Figure 24 This is a cross-sectional view showing the surface-emitting laser module of Embodiment 7.

[0060] A groove or step is provided on the outer periphery of the upper surface of the surface-emitting laser chip 1. A portion of the electrode 4 enters the groove or step. Therefore, a recess 14 is provided on the upper surface of the electrode 4 on the outer periphery side of the surface-emitting laser chip 1. The bonding material 7 flows into the recess 14 of the electrode 4 on the outer periphery side of the chip, thereby preventing the bonding material 7 from flowing out to the light emitting surface 2 on the central side of the chip. Other structures and effects are the same as in Embodiment 1.

[0061] Explanation of reference numerals in the attached figures

[0062] 1…Surface-emitting laser chip; 2…Light emitting surface; 4…Electrode; 6…Lead frame; 6a…Opening; 6b…Joint; 6c…Through hole; 7…Joint material; 8…Molding resin; 11…Protrusion; 12…Comb structure; 13…Solder foot; 14…Recess.

Claims

1. A surface-emitting laser module, characterized in that, have: A surface-emitting laser chip, a portion of its upper surface is a light-emitting surface; Electrodes are disposed on the upper surface of the surface-emitting laser chip in a manner that surrounds the light-emitting surface; A lead frame having an opening located opposite the light emitting surface and a joint around the opening; as well as A bonding material that bonds the electrode to the bonding portion. A through hole extending vertically through the lead frame is provided at the joint.

2. The surface-emitting laser module according to claim 1, characterized in that, A portion of the bonding material flows into the through hole.

3. The surface-emitting laser module according to claim 1 or 2, characterized in that, The lead frame is provided with a plurality of through holes in such a manner as to surround the opening.

4. The surface-emitting laser module according to claim 1 or 2, characterized in that, When viewed from above, the through hole extends in a straight line along the outer periphery of the opening.

5. The surface-emitting laser module according to any one of claims 1 to 4, characterized in that, The through hole is a conical shape that widens from the lower surface of the lead frame toward the upper surface.

6. The surface-emitting laser module according to any one of claims 1 to 4, characterized in that, The through hole is an inverted cone shape that narrows from the lower surface of the lead frame toward the upper surface.

7. The surface-emitting laser module according to any one of claims 1 to 6, characterized in that, It also includes a molding resin for sealing the surface-emitting laser chip and the lead frame. The molding resin covers the upper surface of the joint. A portion of the molding resin flows into the through hole from the upper surface side of the joint.

8. A surface-emitting laser module, characterized in that, have: A surface-emitting laser chip, a portion of its upper surface is a light-emitting surface; Electrodes are disposed on the upper surface of the surface-emitting laser chip in a manner that surrounds the light-emitting surface; A lead frame having an opening located opposite the light emitting surface and a joint around the opening; as well as A bonding material that bonds the electrode to the bonding portion. A protrusion is provided on the lower surface of the lead frame between the opening and the joint.

9. The surface-emitting laser module according to claim 8, characterized in that, The protrusion blocks the bonding material to prevent it from flowing out onto the light emitting surface.

10. A surface-emitting laser module, characterized in that, have: A surface-emitting laser chip, a portion of its upper surface is a light-emitting surface; Electrodes are disposed on the upper surface of the surface-emitting laser chip in a manner that surrounds the light-emitting surface; A lead frame having: an opening located opposite the light emitting surface, and a joint located around the opening; as well as A bonding material that bonds the electrode to the bonding portion. A comb-like structure is provided on the sidewall of the opening.

11. The surface-emitting laser module according to claim 10, characterized in that, A portion of the bonding material is housed within the comb structure and forms a weld foot.

12. A surface-emitting laser module, characterized in that, have: A surface-emitting laser chip, a portion of its upper surface is a light-emitting surface; Electrodes are disposed on the upper surface of the surface-emitting laser chip in a manner that surrounds the light-emitting surface; A lead frame having an opening located opposite the light emitting surface and a joint around the opening; as well as A bonding material that bonds the electrode to the bonding portion. A recess is provided on the upper surface of the electrode on the outer periphery of the surface-emitting laser chip.

13. A method for manufacturing a surface-emitting laser module, characterized in that, It includes the following processes: The process of forming electrodes on the upper surface of a surface-emitting laser chip in a manner that surrounds the light emission surface of the surface-emitting laser chip; The process of forming an opening in the lead frame and forming a through hole in the joint around the opening to allow the lead frame to pass through vertically. The process of coating the electrode with a bonding material; The process of arranging the opening of the lead frame in a position facing the light emission surface and placing the joint of the lead frame on the bonding material; as well as The process of melting the bonding material by heating and then using the molten bonding material to bond the electrode to the bonding portion.

14. A method for manufacturing a surface-emitting laser module, characterized in that, It includes the following processes: The process of forming electrodes on the upper surface of a surface-emitting laser chip in a manner that surrounds the light emission surface of the surface-emitting laser chip; The process of forming an opening in the lead frame and forming a through hole in the joint around the opening to allow the lead frame to pass through vertically. The process of arranging the opening of the lead frame in a position opposite to the light emission surface, arranging the bonding portion above the electrode in a manner that does not contact the electrode, and coating the bonding portion with bonding material. as well as The process of melting the bonding material by heating, and then using the molten bonding material that has passed through the through hole to bond the electrode to the bonding portion.

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