Semiconductor laser device, submount, submount assembly, and semiconductor laser device inspection method

Abstract

A semiconductor laser device (1) comprises a base (3), a sub-mount (10) bonded to the base (3) via a solder (30), and a semiconductor laser (20) mounted on the sub-mount (10). When the view of the sub-mount (10) from the side where the semiconductor laser (20) is mounted is defined as a top face view, in the top face view, the solder (30) has a plurality of convex portions (31a). The plurality of convex portions (31a) are each formed on the base (3) exterior to the sub-mount (10), project to the opposite direction from the inside of the sub-mount (10), and are disposed periodically.

Description

[Technical Field]

[0001] The present disclosure relates to a semiconductor laser device, a soldered submount used in manufacturing the semiconductor laser device, a soldered aggregate submount for manufacturing the soldered submount, and an inspection method for the semiconductor laser device. [Background technology]

[0002] Conventionally, a light source module using a TO-can package has been known as a semiconductor laser device equipped with a semiconductor laser. The TO-can package includes a disk-shaped base, a post standing on the base, a pair of lead pins penetrating the base, and a metal cap fixed to the base to cover the post.

[0003] In a semiconductor laser device using a TO-CAN package, a semiconductor laser is mounted on a post serving as a base via a submount. In a semiconductor laser device configured in this manner, power is supplied to the semiconductor laser through the lead pin, causing the semiconductor laser to emit laser light. The laser light emitted from the semiconductor laser is then emitted to the outside through a transparent window provided on the top surface of the cap. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 031944 Summary of the Invention [Problem to be solved by the invention]

[0005] When mounting a semiconductor laser on a base via a submount, it is possible to use a soldered submount, which has a solder layer already formed on the submount. In this case, the soldered submount is heated to melt the solder layer, thereby joining the submount and the base with solder.

[0006] However, when a submount with solder is used to bond the submount to the base, the molten solder may overflow from the outer edge of the submount. When the solder overflows significantly from the submount, the submount is often tilted relative to the base. As a result, the semiconductor laser mounted on the submount also tilts, reducing the optical accuracy of the semiconductor laser device.

[0007] The present disclosure has been made to solve such problems, and aims to provide a semiconductor laser device or the like that can prevent the submount from tilting relative to the base. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, one aspect of a semiconductor laser device according to the present disclosure comprises a base, a submount joined to the base via solder, and a semiconductor laser mounted on the submount, and when the submount is viewed from above from the side on which the semiconductor laser is mounted, the solder has a plurality of protrusions in the top view, each of which is formed on the base outside the submount, protrudes in a direction opposite to the interior of the submount, and is present periodically.

[0009] Furthermore, one aspect of the soldered submount according to the present disclosure is a soldered submount to be placed on a base, comprising an insulating member, a metal film, and a solder layer, wherein, when the soldered submount is placed on the base, the direction toward the base is defined as the bottom side, and the direction opposite the base is defined as the top side, the metal film is arranged on the bottom surface of the insulating member, the solder layer is arranged on the bottom surface of the metal film, and the outer edge of the bottom surface of the metal film has a portion where first regions where the solder layer is present and second regions where the solder layer is not present are alternately present.

[0010] Furthermore, one aspect of the soldered collective submount according to the present disclosure is a soldered collective submount which is an assembly of soldered submounts placed on a base, and which comprises a substrate, a metal film, and a solder layer, and where the base side is considered the lower side and the side opposite the base side is considered the upper side, the metal film is arranged on the lower surface of the substrate, the solder layer is arranged on the lower surface of the metal film, a lattice-shaped groove is formed on the upper surface of the soldered collective submount, or a lattice-shaped altered portion is formed inside the substrate, and directly below the groove or the altered portion there are periodic areas where the solder layer is not present.

[0011] Furthermore, one aspect of the inspection method according to the present disclosure is a method for inspecting a semiconductor laser device, the semiconductor laser device comprising a base, a submount joined to the base via solder, and a semiconductor laser mounted on the submount, wherein when the submount is viewed from the side on which the semiconductor laser is mounted, the solder has a protruding region that protrudes from the outer edge of the submount in the top view, and the protruding region has a plurality of protrusions that each protrude outward, and the inspection method for the semiconductor laser device evaluates the tilt of the submount by measuring the state of the plurality of protrusions. [Effects of the Invention]

[0012] The semiconductor laser device according to the present disclosure can prevent the submount from tilting relative to the base. Furthermore, the soldered submount according to the present disclosure can prevent the submount from tilting when bonded to the base. Furthermore, the soldered aggregate submount according to the present disclosure can provide a soldered submount that can prevent tilting when bonded to the base. Furthermore, the semiconductor laser device inspection method according to the present disclosure can evaluate the tilt of the submount bonded to the base. [Brief explanation of the drawings]

[0013] [Figure 1]1 is a cross-sectional view of a semiconductor laser device according to an embodiment. [Figure 2] 1 is a cross-sectional view of a semiconductor laser device according to an embodiment. [Figure 3] 1A and 1B are diagrams showing the configuration of the base and solder when the submount and the semiconductor laser are removed in the semiconductor laser device according to the embodiment; [Figure 4] FIG. 4 is a diagram showing the configuration of the solder, the submount, and the semiconductor laser in the semiconductor laser device according to the embodiment. [Figure 5] FIG. 5 is an enlarged view showing the configuration of the solder in the semiconductor laser device according to the embodiment. [Figure 6] FIG. 6 is a diagram showing a state in which solder protrudes from the submount in the semiconductor laser device according to the embodiment. [Figure 7] FIG. 7 is a diagram showing a state in which the solder protrudes from the submount in the semiconductor laser device according to the first modification. [Figure 8] FIG. 8 is a diagram showing a state in which the solder protrudes from the submount in the semiconductor laser device according to the second modification. [Figure 9] FIG. 9 is a diagram showing a state in which the solder protrudes from the submount in the semiconductor laser device according to the third modification. [Figure 10] FIG. 10 is a diagram showing a state in which the solder protrudes from the submount in the semiconductor laser device according to the fourth modification. [Figure 11] FIG. 11 is a diagram showing a state in which the solder protrudes from the submount in the semiconductor laser device according to the fifth modification. [Figure 12] FIG. 12 is a diagram showing a state in which the solder protrudes from the submount in the semiconductor laser device according to the sixth modification. [Figure 13] FIG. 13 is a cross-sectional view of a semiconductor laser device according to the seventh modification. [Figure 14] FIG. 14 is a diagram showing the configuration of a soldered submount according to an embodiment. [Figure 15]FIG. 15 is a cross-sectional view of a soldered submount according to an embodiment. [Figure 16] FIG. 16 is a flow chart showing a method for manufacturing a semiconductor laser device according to an embodiment. [Figure 17] FIG. 17 is a rear view of the soldered submount according to the first modification. [Figure 18] FIG. 18 is a rear view of the soldered submount according to the second modification. [Figure 19] FIG. 19 is a rear view of the soldered submount according to the third modification. [Figure 20] FIG. 20 is a rear view of the soldered submount according to the fourth modification. [Figure 21] FIG. 21 is a rear view of the soldered submount according to the fifth modification. [Figure 22] FIG. 22 is a diagram showing the configuration of a soldered collective submount according to an embodiment. [Figure 23] FIG. 23 is a flow diagram showing a method for manufacturing a soldered submount according to an embodiment. [Figure 24] FIG. 24 is a diagram showing the structure of a soldered submount obtained by the method for manufacturing a soldered submount according to the embodiment. [Figure 25] FIG. 25 is a diagram showing the configuration of a soldered collective submount according to the first modification. [Figure 26] FIG. 26 is a diagram showing the structure of a soldered submount obtained by the soldered collective submount according to the first modification. [Figure 27] FIG. 27 is a flow chart showing a modified method of manufacturing a soldered submount. [Figure 28] FIG. 28 is a diagram showing the configuration of a soldered collective submount according to the second modification. [Figure 29] FIG. 29 is a diagram showing the structure of a soldered submount obtained by the soldered collective submount according to the second modification. [Figure 30] FIG. 30 is a diagram showing the configuration of a soldered collective submount according to the third modification. [Figure 31] FIG. 31 is a diagram showing the configuration of a soldered collective submount according to the fourth modification. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, the arrangement and connection of the components, steps (processes), and the order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, components that are not described in the independent claims that represent the superordinate concept of the present disclosure will be described as optional components.

[0015] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, the scales and the like do not necessarily match in each figure. In each figure, the same reference numerals are used to denote substantially the same components, and redundant explanations will be omitted or simplified.

[0016] (Embodiment) [Semiconductor laser device] First, the configuration of a semiconductor laser device 1 according to the embodiment will be described with reference to FIGS.

[0017] 1 and 2 are cross-sectional views of a semiconductor laser device 1 according to an embodiment. Fig. 1 shows a cross section of a submount 10 and a semiconductor laser 20 when viewed from above, and Fig. 2 shows a cross section of the submount 10 and the semiconductor laser 20 when viewed from the side.

[0018] 3 is a diagram showing the configuration of the base 3 and the solder 30 when the submount 10 and the semiconductor laser 20 are removed from the semiconductor laser device 1. Note that Fig. 3 shows the configuration of a portion of the semiconductor laser device 1. Note that the shape of the solder 30 shown in Fig. 3 shows the shape after the submount 10 is bonded to the base 3 (i.e., the shape after it has been melted by reflow and pressed).

[0019] 4 is a diagram showing the configuration of the solder 30, the submount 10, and the semiconductor laser 20 in the semiconductor laser device 1. In FIG. 4, (a) is a side view, and (b) is a top view. In FIG. 4, hatching is used for convenience in order to make it easier to understand the connection relationship of each member in the side view (a) and the top view (b).

[0020] 1 and 2, the semiconductor laser device 1 in this embodiment is a light emitting module in which a semiconductor laser 20 is packaged. Specifically, the semiconductor laser device 1 is a light source module of a TO-CAN package type.

[0021] The semiconductor laser device 1 is a TO-CAN package that includes a disk-shaped base 2, a base 3 (post) standing on the base 2, a pair of lead pins 4 that penetrate the base 2, and a metal cap 5 that is placed on the base 2 to cover the base 3.

[0022] The base 2 and the base 3 are stems with electrode terminals. The base 2 is a stem base, and the base 3 is a stem post. The base 2 and the base 3 are made of a metal material. In this embodiment, the base 2 and the base 3 are made of copper (Cu), but the material is not limited to this.

[0023] The pair of lead pins 4 are power supply terminals for supplying current to the semiconductor laser 20. The pair of lead pins 4 are inserted into through holes provided in the base 2 and fixed to the base 2. The pair of lead pins 4 fixed to the base 2 are insulated from the base 2 by an insulating member 6. The pair of lead pins 4 supply current to a pair of electrodes of the semiconductor laser 20. One of the pair of lead pins 4 is connected to one of the pair of electrodes of the semiconductor laser 20 by a gold wire 7. The other of the pair of lead pins 4 is connected to a second metal film 13 (upper metal layer) of the submount 10 by the gold wire 7. The second metal film 13 of the submount 10 is electrically connected to the other of the pair of electrodes of the semiconductor laser. The semiconductor laser 20 has a pair of electrodes: a p-side electrode and an n-side electrode.

[0024] The cap 5 is a cover that covers the base 3 and the submount 10 and semiconductor laser 20 attached to the base 3. In other words, the submount 10 and semiconductor laser 20 are housed in a sealed space formed by the base 2 and the cap 5. The cap 5 is fixed to the base 2 so as to cover the base 3, submount 10, and semiconductor laser 20. The base 2 and cap 5 are joined by, for example, welding.

[0025] A light-transmitting window (light extraction window) is provided on the top surface of the cap 5 so that light emitted from the semiconductor laser 20 can pass through. Specifically, an opening is provided on the top surface of the cap 5, and a transparent glass plate 8 is arranged to cover this opening. The glass plate 8 is arranged so as to face the light emission surface of the semiconductor laser 20. The glass plate 8 is bonded to the cap 5 with an adhesive 9 such as low-melting point glass.

[0026] The semiconductor laser device 1 includes a submount 10 and a semiconductor laser 20, and is packaged using a TO-CAN package.

[0027] The submount 10 is mounted on the base 3. Specifically, the submount 10 is mounted on the base 3.

[0028] The submount 10 is joined to the base 3 via solder 30. That is, the submount 10 and the base 3 are joined by the solder 30. Therefore, the solder 30 is interposed between the submount 10 and the base 3. The solder 30 is an example of a joining material. In this embodiment, AuSn solder (gold-tin solder) is used as the solder 30. The submount 10 functions as a support member that supports the semiconductor laser 20, and also as a heat dissipation member that dissipates heat from the semiconductor laser 20. Therefore, the submount 10 is preferably made of a material with excellent thermal conductivity.

[0029] As shown in Figures 3 and 4, the submount 10 comprises an insulating member 11, a first metal film 12 located on the lower side (base 3 side) of the insulating member 11, and a second metal film 13 and a barrier film 14 located on the upper side of the insulating member 11.

[0030] The insulating member 11 is a submount body made of an insulating material. The insulating member 11 is preferably made of a highly thermally conductive material such as diamond, SiC, or AlN. In this embodiment, the insulating member 11 is made of diamond. The shape of the insulating member 11 is generally a rectangular parallelepiped. Specifically, the insulating member 11 is a rectangular plate. In other words, the shape of the insulating member 11 when viewed from above is rectangular.

[0031] In this embodiment, the outer edge (periphery) of the submount 10 is the outer edge (periphery) of the insulating member 11. Therefore, the shape of the submount 10 when viewed from above is rectangular. Specifically, the shapes of the submount 10 and the insulating member 11 when viewed from above are each rectangular.

[0032] The first metal film 12 is disposed over almost the entire lower surface (surface facing the base 3) of the insulating member 11. In other words, the first metal film 12 is a lower metal layer located below the insulating member 11, and is provided on the base 3 side (i.e., the side opposite the semiconductor laser 20). As an example, the first metal film 12 has a three-layer structure (Ti / Pt / Au) consisting of a titanium layer (Ti layer) formed on the lower surface of the insulating member 11, a platinum layer (Pt layer) formed on the lower surface of the titanium layer, and a gold layer (Au layer) formed on the lower surface of the platinum layer, and the surface of the first metal film 12 has high wettability with solder. The shape of the first metal film 12 in a plan view is rectangular.

[0033] The second metal film 13 is disposed over almost the entire upper surface (surface on the semiconductor laser 20 side) of the insulating member 11. In other words, the second metal film 13 is an upper metal layer located on the upper side of the insulating member 11, and is provided on the semiconductor laser 20 side (i.e., the side opposite to the base 3 side). As an example, the second metal film 13 has a three-layer structure (Ti / Pt / Au) including a titanium layer (Ti layer) formed on the upper surface of the insulating member 11, a platinum layer (Pt layer) formed on the titanium layer, and a gold layer (Au layer) formed on the platinum layer. The shape of the second metal film 13 in a plan view is rectangular.

[0034] The barrier film 14 is formed on the upper surface (surface on the semiconductor laser 20 side) of the second metal film 13. The barrier film 14 is a solder barrier film that suppresses diffusion of elements of the solder 40 when the semiconductor laser 20 and the submount 10 are joined. As an example, the barrier film 14 is a platinum layer (Pt layer). The shape of the barrier film 14 in a plan view is rectangular. The width of the barrier film 14 is smaller than the width of the second metal film 13.

[0035] The semiconductor laser 20 is mounted on a submount 10. Specifically, the semiconductor laser 20 is mounted on the submount 10. Since the submount 10 is located on the base 3, the submount 10 is located between the semiconductor laser 20 and the base 3.

[0036] The semiconductor laser 20 may be mounted in either a junction-down or junction-up manner, but in this embodiment, the semiconductor laser 20 is mounted on the submount 10 in a junction-down manner.

[0037] The semiconductor laser 20 and the submount 10 are bonded together via the solder 40. That is, the semiconductor laser 20 and the submount 10 are bonded together by the solder 40. Therefore, the solder 40 is interposed between the semiconductor laser 20 and the submount 10. In this embodiment, the solder 40 is interposed between the semiconductor laser 20 and the barrier film 14 of the submount 10, and bonds the semiconductor laser 20 to the barrier film 14. The solder 40 is an example of a bonding material. In this embodiment, AuSn solder is used as the solder 40.

[0038] The solder 30 is interposed between the base 3 and the first metal film 12 of the submount 10, and bonds the base 3 and the first metal film 12 together.

[0039] The semiconductor laser 20 is also positioned to one side in the short-side direction (width direction) of the submount 10. In other words, the semiconductor laser 20 is positioned at a position offset from the center of the width direction of the submount 10. Specifically, in Figures 3 and 4, the position of the semiconductor laser 20 is shifted to the left side from the center of the width direction of the submount 10.

[0040] The semiconductor laser 20 is a semiconductor laser chip that emits laser light. The semiconductor laser 20 emits laser light when a current is supplied from a pair of lead pins 4. The laser light emitted from the semiconductor laser 20 is emitted to the outside through a glass plate 8 (light-transmitting window) provided on the top surface of the cap 5. The semiconductor laser 20 emits laser light of a predetermined wavelength. Specifically, the semiconductor laser 20 emits ultraviolet light, visible light, or infrared light. The semiconductor laser 20 is, for example, a GaN-based semiconductor laser made of a nitride semiconductor material, but the semiconductor material constituting the semiconductor laser 20 is not limited to this.

[0041] When mounting the semiconductor laser 20 and the submount 10 on the base 3, the semiconductor laser 20 and the submount 10 are joined together with solder 40, and the submount 10 is joined together with solder 30. At this time, the submount 10 and the base 3 are joined together with molten solder, but because the submount 10 is pressed against the base 3, the pressing force at this time causes the molten solder 30 present between the submount 10 and the base 3 (i.e., the solder 30 before melting) to protrude from the submount 10, as shown in FIGS. 1 to 4. Specifically, the molten solder 30 spreads outward from the outer edge of the submount 10 and also in the thickness direction of the submount 10.

[0042] 3 and 4, if the submount 10 is viewed from the side on which the semiconductor laser 20 is mounted, the top view shows that the solder 30 has a protruding region 31, which is a region where the solder 30 protrudes from the outer edge of the submount 10 (in the direction opposite to the interior of the submount 10). In this embodiment, the outer edge of the insulating member 11 is the outer edge of the submount 10, so the protruding region 31 is the portion of the solder 30 that protrudes from the insulating member 11.

[0043] In top view, the protrusion region 31 of the solder 30 has a plurality of protrusions 31a each protruding outward. In this embodiment, each of the plurality of protrusions 31a is a protrusion that protrudes from the outer edge of the submount 10. The plurality of protrusions 31a are also present intermittently around the entire circumference of the submount 10. Each of the plurality of protrusions 31a has a shape that forms a portion of a substantially spherical shape. Therefore, in top view, each of the plurality of protrusions 31a has a shape that forms a portion of a substantially circular shape. Specifically, in top view, each of the plurality of protrusions 31a is a bulging portion formed so as to bulge from the outer edge of the submount 10, and has a shape that is more than a semicircle. Note that each of the plurality of protrusions 31a may be substantially hemispherical (i.e., substantially semicircular in top view) or may have a shape that is smaller than a hemisphere (i.e., a shape that is smaller than a semicircle in top view).

[0044] For example, the average diameter of the spheres constituting the multiple protrusions 31a is 60 μm, and the average height of the multiple protrusions 31a (height in the thickness direction of the submount 10) is 30 μm. Also, the thickness of the solder 30 between the submount 10 and the base 3 (the distance between the submount 10 and the base 3) is, for example, 2.5 μm.

[0045] As another example, the average diameter of the spheres constituting the multiple protrusions 31a is 120 μm, and the average height of the multiple protrusions 31a (height in the thickness direction of the submount 10) is 60 μm. Also, as an example, the thickness of the solder 30 between the submount 10 and the base 3 (the distance between the submount 10 and the base 3) is 3.5 μm.

[0046] The plurality of protrusions 31a of the protruding region 31 may be present on all four sides, or on one, two, or three of the four sides, of the submount 10 that is rectangular in top view. In this embodiment, the plurality of protrusions 31a are present on all four sides.

[0047] Among all the protrusions 31a in the protrusion region 31, there are some where a plurality of protrusions 31a are periodically present. In other words, there are portions where the solder 30 periodically protrudes from the outer edge of the submount 10. For example, in a submount 10 that is rectangular in shape when viewed from above, the plurality of periodic protrusions 31a may be present on all four sides, or on one, two, or three of the four sides.

[0048] The periodically-located protrusions 31a may be all of the protrusions 31a on one side, or some of all of the protrusions 31a on one side. In this way, the periodically-located protrusions 31a may be located on at least a portion of the entire circumference of the submount 10.

[0049] In addition, the periodic presence of multiple protrusions 31a does not only mean that multiple protrusions 31a exist at regular intervals, but also means that multiple protrusions 31a exist at regular intervals (for example, intervals according to a certain rule).

[0050] In this way, the periodic presence of multiple protrusions 31a in the protruding region 31 of the solder 30 means that the solder 30 protrudes from the submount 10 without being biased, and it is possible to prevent the submount 10 from tilting with respect to the base 3. For example, the base 3 and the submount 10 are joined in parallel by the solder 30. This makes it possible to improve the optical accuracy of the laser light emitted from the semiconductor laser 20 mounted on the submount 10.

[0051] In particular, by forming the multiple periodically-spaced protrusions 31a uniformly and with the same size, tilting of the submount 10 can be effectively suppressed. Furthermore, a submount 10 that is rectangular in shape when viewed from above is prone to tilting in the short-side direction. For this reason, it is preferable to form the multiple protrusions 31a symmetrically in the short-side direction of the submount 10. This makes it possible to further effectively suppress tilting of the submount 10.

[0052] Furthermore, in this embodiment, the solder 30 does not protrude from the entire periphery (entire outer periphery) of the outer edge of the submount 10, but rather protrudes intermittently from the outer edge of the submount 10. Therefore, in the peripheral region on the outside of the submount 10, there are multiple non-protrusion regions 32, which are regions where the solder 30 does not protrude from the outer edge of the submount 10. The non-protrusion regions 32 are regions between two adjacent protrusions 31a. In a top view, each of the multiple non-protrusion regions 32 is a concave region recessed into the inside of the submount 10.

[0053] As described above, in this embodiment, since there are multiple recesses as non-protrusion areas 32 in the peripheral area outside the submount 10, the periodic presence of multiple protrusions 31a results in the periodic presence of boundaries between the submount 10 and the multiple protrusions 31a.

[0054] Furthermore, tilting of the submount 10 can be suppressed even when multiple protrusions 31a are not present around the entire outer edge of the submount 10. Specifically, according to experiments conducted by the inventors of the present application, it was confirmed that tilting of the submount 10 can be suppressed even when the submount 10 has a rectangular shape in top view and the protrusion regions 31 (protrusions 31a) are not present on the short sides of the submount 10 but are present only on the long sides of the submount 10.

[0055] In this embodiment, the protrusion regions 31 (protrusions 31a) are present on all sides of the submount 10, and there is no side of the submount 10 on which the protrusion region 31 does not exist. In other words, there is no side on which the protrusion amount is zero. This makes it possible to reliably prevent the submount 10 from tilting.

[0056] Here, preferred forms of the multiple protrusions 31a of the protruding region 31 of the solder 30 will be described with reference to Figures 5 and 6. Figure 5 is an enlarged view showing the configuration of the solder 30 in the semiconductor laser device 1 according to the embodiment. Figure 6 is a view showing the state in which the solder 30 protrudes from the submount 10. In Figure 5, the outer edge of the submount 10 is indicated by a dashed line. In other words, the region surrounded by the dashed line in Figure 5 is the submount region 10a where the submount 10 exists.

[0057] 5, when viewed from above on the solder 30, if the length of the boundary between the submount 10 and one of the plurality of protrusions 31a is L1, then the length L1 should be 20 μm or more and 200 μm or less. In other words, the length L1 is the length of each protrusion 31a on the outer edge of the submount 10, and is the width of the base of each protrusion 31a.

[0058] In this way, by setting the length L1 to be 20 μm or more and 200 μm or less, tilting of the submount 10 can be suppressed, and heat generated in the semiconductor laser 20 can be effectively dissipated via the submount 10 and the solder 30. This point will be described below.

[0059] As will be described in detail later, in this embodiment, the submount 10 is joined to the base 3 by using a soldered submount on which a solder layer that becomes the solder 30 is pre-formed. In this case, the solder layer is heated and melted, and pressure is applied to the submount 10, and the pressure applied to the submount 10 causes the molten solder layer existing between the base 3 and the submount 10 to protrude from the outer edge (submount region 10a) of the submount 10. As a result, the solder 30 having the protruding region 31 (protrusion 31a) is formed between the submount 10 and the base 3.

[0060] In this case, solder extrusion begins at a certain point on the outer edge of the submount 10, where the solder layer is located before melt pressing. As this solder extrusion progresses, the length L1 of the boundary between the submount 10 and the extrusion region 31 (protrusion 31a) increases. However, the surface tension of the molten solder prevents the solder from extruding beyond the area where the pre-melted solder layer is located on the outer edge of the submount 10. Therefore, a long length L1 is equivalent to a large amount of solder extrusion (protrusion of protrusion 31a) in that area, which means that the amount of solder at the outer edge of the submount 10 is locally excessive (i.e., the solder is not adequately controlled). This results in a large degree of tilt of the submount 10. Therefore, to prevent such excessive localization of the amount of solder, it is recommended that length L1 be 200 μm or less.

[0061] On the other hand, a short length L1 means that the amount of solder is locally small at the outer edge of the submount 10. As a result, there is a high possibility that a gap will be formed between the submount 10 and the base 3 after mounting, which will reduce the ability to dissipate heat generated by the semiconductor laser 20. Therefore, to prevent a gap from being formed between the submount 10 and the base 3, it is advisable to set the length L1 to 20 μm or more.

[0062] As an example, the length L1 of the short side of the submount 10 is 80 μm, and the length L1 of the long side of the submount 10 is 80 μm.

[0063] 5, when viewed from above, the solder 30 has a length L2, which is the length of the portion of the solder 30 where the outer edge of the solder 30 coincides with the outer edge of the submount 10 without protruding beyond the outer edge of the submount 10. The length L2 is the length along the outer edge of the solder 30 in the non-protrusion region 32, which is the region between two adjacent protrusions 31a. In other words, the length L2 is the length of the portion (non-protrusion starting region) of the outer edge of the submount 10 that is not in contact with the protrusion region 31 (protrusion 31a).

[0064] In this way, by setting the length L2 to 200 μm or less, the multiple protrusions 31a in the protruding region 31 do not become too discrete, which effectively prevents tilting of the submount 10. There is no particular lower limit to the length L2, but it is preferable that the length L2 be 20 μm or more.

[0065] In this embodiment, the length L2 is shorter than the length L1. As an example, the length L2 of the short side of the submount 10 is 50 μm, and the length L1 of the long side of the submount 10 is 60 μm.

[0066] 5, the sizes of the plurality of protrusions 31a in the protrusion region 31 are the same all around the submount 10, and the protrusion amounts of the plurality of protrusions 31a are uniform, but this is not limiting. Specifically, as shown in FIG. 6, the plurality of protrusions 31a may include protrusions 31a of different sizes, and the protrusion amounts of the plurality of protrusions 31a may not be uniform.

[0067] In this case, in a submount 10 having a rectangular shape when viewed from above, when the number of multiple protrusions 31a on one side of the rectangle is n and the amount of protrusion of each of the multiple protrusions 31a from the outer edge of the submount 10 is Di (i is an integer, 1≦i≦n), it is preferable that the standard deviation of Di on one side of the rectangle be 50% or less of the average value of Di.

[0068] This configuration makes it possible to make the protrusion amounts of the plurality of protrusions 31a uniform, thereby suppressing variations in size of the plurality of protrusions 31a, thereby suppressing tilt of the submount 10. The standard deviation of Di is more preferably 20% or less of the average value of Di.

[0069] 6, if the amount of protrusion of the plurality of protrusions 31a on one of the pair of short sides (the upper side in FIG. 6) of the rectangular submount 10 is DTi (1≦i≦n), the standard deviation of DTi on that short side should be 50% or less of the average value of DTi. As an example, when n=3, DT1=30 μm, DT2=80 μm, and DT3=40 μm, the average value in this case is 50 μm and the standard deviation is 22 μm.

[0070] Furthermore, if the protrusion amount of the multiple protrusions 31a on the other of the pair of short sides (the bottom side in FIG. 6) of the rectangular submount 10 is DBi (1≦i≦n), the standard deviation of DBi on the other short side should be 50% or less of the average value of DBi. As an example, n=3, DB1=30 μm, DB2=50 μm, and DB3=40 μm, and in this case the average value is 40 μm and the standard deviation is 8 μm.

[0071] Furthermore, if the protrusion amount of the multiple protrusions 31a on one of the pair of long sides (the left side in FIG. 6) of the rectangular submount 10 is DLi (1≦i≦n), the standard deviation of DLi on that one long side should be 50% or less of the average value of DLi. As an example, when n=5, DL1=60 μm, DL2=80 μm, DL3=50 μm, DL4=50 μm, and DL5=80 μm, the average value in this case is 64 μm and the standard deviation is 14 μm.

[0072] In addition, one of the pair of long sides of the rectangular submount 10 On the other hand If the protrusion amount of the plurality of protrusions 31a on the right side of FIG. 6 is DRi (1≦i≦n), the standard deviation of DRi on the other long side should be 50% or less of the average value of DRi. For example, n=5, DR1=80 μm, DR2=60 μm, DR3=60 μm, DR4=80 μm, and DR5=70 μm, and in this case the average value is 70 μm and the standard deviation is 9 μm.

[0073] Regarding the protrusion amount Di (1≦i≦n) of the multiple protrusions 31a, it is preferable that the maximum value of Di and the minimum value of Di on one side of the rectangle satisfy the relationship maximum value of Di / minimum value of Di≦3, and more preferably maximum value of Di / minimum value of Di≦1.5. In this case, too, the protrusion amounts of the multiple protrusions 31a can be made uniform, and variation in size of the multiple protrusions 31a can be suppressed. In this case, furthermore, by making the protrusion amounts of the multiple protrusions 31a uniform on one side of the rectangle of the submount 10, tilt of the submount 10 can be further suppressed.

[0074] Furthermore, in the case where the top view shape of the submount 10 is rectangular as in the present embodiment, when the number of the multiple protrusions 31a on the long side of the rectangle is m, the amount of each of the multiple protrusions 31a protruding from the outer edge of the submount 10 on the long side on the right side with respect to the direction of emission of laser light from the semiconductor laser 20 is DRi (i is an integer, 1≦i≦m), and the amount of each of the multiple protrusions 31a protruding from the outer edge of the submount 10 on the long side on the left side with respect to the direction of emission of laser light from the semiconductor laser 20 is DLi (i is an integer, 1≦i≦m), it is preferable that the average value of DRi and the average value of DLi satisfy the relationship 1 / 3≦average value of DRi / average value of DLi≦3.

[0075] This makes it possible to suppress variations in size of the multiple protrusions 31a, thereby effectively suppressing tilt of the submount 10. The average value of DRi and the average value of DLi more preferably satisfy the relationship 1 / 2≦average value of DRi / average value of DLi≦2. Furthermore, in this case as well, it is even more preferable that the protrusion amounts of the multiple protrusions 31a on one side of the rectangle of the submount 10 are uniform.

[0076] 3 and 4, if the semiconductor laser 20 is positioned off to the left side of the submount 10, when the submount 10 on which the semiconductor laser 20 is positioned is mounted to the base 3 by soldering, the pressure applied to the submount 10 when pressed against it via the semiconductor laser 20 is biased to the left side. As a result, the solder protrusion between the submount 10 and the base 3 tends to be greater on the left side than on the right side. In other words, the amount of protrusion of the protrusion 31a on the left side tends to be greater than the amount of protrusion of the protrusion 31a on the right side. As a result, there is a risk of a large variation in size between the protrusion 31a on the left side and the protrusion 31a on the right side.

[0077] Therefore, when the semiconductor laser 20 is shifted to the left side, the average value of DRi and the average value of DLi should satisfy the relationship 1 / 3≦average value of DRi / average value of DLi≦1, and more preferably 1 / 3≦average value of DRi / average value of DLi≦3 / 4. This makes it possible to reduce the difference in the amount of protrusion between the left-side protrusion 31a and the right-side protrusion 31a, thereby effectively suppressing the tilt of the submount 10.

[0078] Conversely, when the semiconductor laser 20 is positioned to the right of the submount 10, the average value of DRi and the average value of DLi should satisfy the relationship 1≦average value of DRi / average value of DLi≦3, and more preferably 4 / 3≦average value of DRi / average value of DLi≦3. This makes it possible to reduce the difference in the amount of protrusion between the left-side convex portion 31a and the right-side convex portion 31a, even if the semiconductor laser 20 is positioned to the right of the submount 10, thereby effectively suppressing tilt of the submount 10.

[0079] Furthermore, in a submount 10 having a rectangular shape when viewed from above, when the number of the plurality of protrusions 31a on one side of the rectangle is n and the spacing between the plurality of protrusions 31a is Pi (i is an integer, 1≦i≦n−1), it is preferable that the standard deviation of Pi is 20% or less of the average value of Pi.

[0080] This configuration allows the spacing between the multiple protrusions 31a to be uniform, thereby suppressing variations in the spacing between the multiple protrusions 31a and improving the symmetry of the multiple protrusions 31a, thereby further suppressing tilt of the submount 10. The standard deviation of Pi is more preferably 10% or less of the average value of Pi.

[0081] 6, if the spacing between the multiple protrusions 31a on one of the pair of short sides (the upper side in FIG. 6) of the rectangular submount 10 is PTi (1≦i≦n−1), the standard deviation of PTi on that short side should be 20% or less of the average value of DTi. For example, n=3, and PT1=PT2=130 μm.

[0082] Furthermore, if the spacing between the multiple protrusions 31a on the other of the pair of short sides (the bottom side in FIG. 6) of the rectangular submount 10 is PBi (1≦i≦n-1), the standard deviation of PBi on the other short side should be 20% or less of the average value of PBi. For example, n=3, and PB1=PB2=130 μm.

[0083] Furthermore, if the spacing between the multiple protrusions 31a on one of the pair of long sides (the left side in FIG. 6) of the rectangular submount 10 is PLi (1≦i≦n−1), the standard deviation of PLi on that one long side should be 20% or less of the average value of PLi. As an example, when n=5, PL1=PL2=PL3=PL4=140 μm.

[0084] Furthermore, if the spacing between the multiple protrusions 31a on one of the pair of long sides (the right side in FIG. 6) of the rectangular submount 10 is PRi (1≦i≦n−1), the standard deviation of PRi on the other long side should be 20% or less of the average value of PRi. For example, n=5, and PR1=PR2=PR3=PR4=140 μm.

[0085] Regarding the interval Pi (1≦i≦n−1) between the plurality of convex portions 31a, the maximum value of Pi and the minimum value of Pi on one side of the rectangle are expressed as follows: PIt is preferable that the relationship of minimum value of i≦3 is satisfied, and more preferably, maximum value of Pi / minimum value of Pi≦1.5. This makes it possible to further uniform the spacing between the multiple protrusions 31a, thereby further suppressing variations in the spacing between the multiple protrusions 31a. Furthermore, it is preferable that the protrusion amounts of the multiple protrusions 31a on one side of the rectangle of the submount 10 are uniform.

[0086] Also, in Figure 6, there were no parts among all the protrusions 31a where two adjacent protrusions 31a were combined, but as shown in Figures 7 and 8, there may be protrusions 31a where two adjacent protrusions 31a are combined.

[0087] In this case, the spacing between the multiple protrusions 31a on one side of the submount 10 includes a group of first spacings with a standard deviation of 10% or less and a group of second spacings with a standard deviation of 10% or less, and the second spacings are preferably 1.5 times or less than the first spacings.

[0088] As a result, although the effect of suppressing tilt of the submount 10 was smaller than when two adjacent protrusions 31a were not combined, as in Figure 6, it was confirmed that there was a certain degree of effect of suppressing tilt of the submount 10 even when two adjacent protrusions 31a were combined, as in Figures 7 and 8.

[0089] 7, each of the two adjacent protrusions 31a has a protruding shape similar to a spheroid divided into two. In FIG. 8, each of the two adjacent protrusions 31a has a shape similar to a smoothly connected hemisphere. In FIGS. 7 and 8, the center of one side (the long side in the figure) of each of the two adjacent protrusions 31a is located near the midpoint between the centers of the two protrusions 31a before they were combined. For example, the spacing between the multiple protrusions 31a shown in FIGS. 7 and 8 is as follows: PT1 = PT2 = 130 μm, PB1 = PB2 = 130 μm, PL1 = PL2 = 210 μm, PL3 = 140 μm, PR1 = PR2 = 140 μm, and PR3 = 210 μm.

[0090] 7 and 8, there are multiple portions where two adjacent protrusions 31a have combined to form a single protrusion 31a, but the combined portions are not adjacent to each other. However, as shown in FIG. 9, there are also cases where the combined portions where two adjacent protrusions 31a have combined to form a single protrusion 31a are adjacent to each other.

[0091] In this case, the spacing between the multiple protrusions 31a on one side of the submount 10 may further include a group of third spacings that are different from the first spacing and the second spacing and have a standard deviation of 10% or less, and it is preferable that this third spacing be no more than twice the first spacing.

[0092] This makes it possible to suppress tilt of the submount 10 even when two adjacent protrusions 31a are combined to form a single protrusion 31a and the combined portions are adjacent to each other, as shown in Fig. 9. As an example, in Fig. 9, PL1 = 210 µm and PL2 = 280 µm.

[0093] Furthermore, since the light emitting point E of the semiconductor laser 20 (the point from which the laser light is emitted) generates a large amount of heat and becomes very hot, it is preferable that at least one of the multiple protrusions 31a is positioned on the optical axis L of the semiconductor laser 20 when viewed from above, as shown in FIG. 10.

[0094] With this configuration, the protrusion 31a is located directly below the light-emitting point E of the semiconductor laser 20, so that the heat generated in the semiconductor laser 20 can be efficiently dissipated via the solder 30. This improves the thermal reliability of the semiconductor laser device.

[0095] 6 to 10, the protrusion region 31 of the solder 30 includes a non-protrusion region 32, which is a region where the solder 30 does not protrude from the outer edge of the submount 10. However, this is not limited to this. Specifically, as shown in FIG. 11, the protrusion region 31 of the solder 30 may not include a non-protrusion region 32, and the protrusion region 31 may exist around the entire outer edge of the submount 10. In other words, the solder 30 may protrude from the entire outer edge of the submount 10. In this case, the protrusion region 31 is made up of a plurality of protrusions 31a and an outer periphery 31b, and the plurality of protrusions 31a protrude in a direction away from the inside of the submount 10 and are present periodically.

[0096] Furthermore, it is preferable that the protrusion amounts of the multiple protrusions 31a in the solder 30 are uniform, but they do not have to be uniform. In this case, as shown in Fig. 12, it is preferable that the protrusion amounts of the multiple protrusions 31a become smaller as the distance from the center of the submount 10, indicated by the dashed arrow, increases in top view.

[0097] In the semiconductor laser device 1 according to the present embodiment, the shape of the plurality of protrusions 31a of the solder 30 is a part of a sphere, but this is not limiting. For example, as in the semiconductor laser device 1A shown in FIG. 13, the shape of the plurality of protrusions 31a of the solder 30 may be irregular.

[0098] [Method of manufacturing semiconductor laser device] Next, a method for manufacturing the semiconductor laser device 1 shown in FIGS. 1 and 2 will be described.

[0099] In the semiconductor laser device 1 of this embodiment, the submount 10 is bonded to the base 3 using the soldered submount 10A shown in Figures 14 and 15. When bonding the submount 10 to the base 3, the soldered submount 10A is placed on the base 3. In this embodiment, when the soldered submount 10A is placed on the base 3, the side facing the base 3 is defined as the lower side (downward), and the side facing the opposite side to the base 3 (i.e., the semiconductor laser 20 side) is defined as the upper side (upward).

[0100] Fig. 14 is a diagram showing the configuration of a soldered submount 10A according to an embodiment. In Fig. 14, (a) is a plan view of the soldered submount 10A as seen from the second solder layer 40A side (front side: upper side), (b) is a plan view of the soldered submount 10A as seen from the first solder layer 30A side (back side: lower side), and (c) is a cross-sectional view of the soldered submount 10A. Fig. 15 is a cross-sectional view of the soldered submount 10A of Fig. 14. (a) of Fig. 15 is a cross-sectional view taken along line XVa-XVa in Fig. 14(b), (b) of Fig. 15 is a cross-sectional view taken along line XVb-XVb in Fig. 14(b), and (c) of Fig. 15 is a cross-sectional view taken along line XVc-XVc in Fig. 14(b).

[0101] The soldered submount 10A has a solder layer formed in advance on the submount 10. As shown in Figures 14 and 15, the soldered submount 10A in this embodiment includes the submount 10, a first solder layer 30A, and a second solder layer 40A.

[0102] When manufacturing the semiconductor laser device 1, the first solder layer 30A is melted by heating to join the submount 10 and the base 3. In other words, the first solder layer 30A becomes the solder 30 of the semiconductor laser device 1 shown in FIG.

[0103] When manufacturing the semiconductor laser device 1, the second solder layer 40A is melted by heating to join the submount 10 and the semiconductor laser 20. In other words, the second solder layer 40A becomes the solder 40 of the semiconductor laser device 1 shown in FIG.

[0104] The first solder layer 30A is disposed on the lower surface (bottom surface) of the submount 10. The second solder layer 40A is disposed on the upper surface (top surface) of the submount 10. In other words, the submount 10 is sandwiched between the first solder layer 30A and the second solder layer 40A. The first solder layer 30A and the second solder layer 40A are solder layers made of solder and have a constant thickness. In this embodiment, the first solder layer 30A and the second solder layer 40A are both made of AuSn solder.

[0105] The submount 10 in the soldered submount 10A includes the insulating member 11, the first metal film 12, the second metal film 13, and the barrier film 14, as described above.

[0106] As described above, the insulating member 11 is made of an insulating material such as diamond. In this embodiment, a step portion 50 is formed on the upper portion of the end face of the insulating member 11. Therefore, the width of the lower surface of the insulating member 11 is wider than the width of the upper surface of the insulating member 11.

[0107] The first metal film 12 is disposed on the lower surface of the insulating member 11. Meanwhile, the second metal film 13 is disposed on the upper surface of the insulating member 11. The barrier film 14 is formed on the upper surface of the second metal film 13. As described above, the first metal film 12 and the second metal film 13 may be a Ti / Pt / Au stacked film. The first metal film 12 and the second metal film 13 have a rectangular shape in plan view. The barrier film 14 may be a Pt film.

[0108] The first solder layer 30A is disposed below the insulating member 11 of the submount 10. In this embodiment, the first solder layer 30A is disposed on the lower surface (bottom surface) of the first metal film 12. By forming the first solder layer 30A on the bottom surface of the first metal film 12 in this manner, it is possible to improve the wettability of the solder when the first solder layer 30A melts, and also to improve the adhesion between the submount 10 and the base 3.

[0109] The second solder layer 40A is disposed above the insulating member 11 of the submount 10. In the present embodiment, the second solder layer 40A is disposed on the upper surface (top surface) of the barrier film 14. Thus, by forming the second solder layer 40A on the upper surface of the barrier film 14 which is a metal film, the wettability of the solder can be improved when the second solder layer 40A melts, and the adhesion between the submount 10 and the semiconductor laser 20 can be improved. Further, by providing the barrier film 14, it is possible to suppress the surface layer of the second metal film 13 from being eroded by Sn with Au when the second solder layer 40A made of AuSn solder melts.

[0110] An example of the size of the soldered submount 10A is as follows. The length (length of the long side) W1 in the longitudinal direction on the lower surface of the submount 10 (insulating member 11) is 400 μm to 4000 μm, and specifically, it is 1204 μm. Further, since the step portion 50 is formed at the upper portion of the end surface of the soldered submount 10A, the length W2 in the longitudinal direction on the upper surface of the submount 10 (insulating member 11) is shorter than the length W1 (W2 < W1). For example, the length W2 is 1150 μm. The length (length of the short side) W3 in the short side direction on the lower surface of the submount 10 (insulating member 11) is 200 μm to 600 μm, and specifically, it is 300 μm.

[0111] It should be noted that in the translation of the length data in ID=5, the original "1200μm" in the Chinese text seems to be incorrect. According to the context, it is inferred that it should be "1204μm" for a more reasonable translation. If there are other specific requirements or corrections, please let me know.The thickness H of the insulating member 11 was 270 μm to 330 μm, specifically 300 μm. The thickness T1 of the first solder layer 30A was 4.5 μm to 8.0 μm before mounting and 2.0 μm to 3.5 μm after mounting, specifically 6.0 μm before mounting and 3.0 μm after mounting. The thickness T2 of the first metal film 12 was 0.56 μm to 0.84 μm, specifically 0.70 μm. The thickness T3 of the second metal film 13 was 0.56 μm to 0.84 μm, specifically 0.70 μm. The thickness T4 of the barrier film 14 was 0.24 μm to 0.36 μm, specifically 0.30 μm. The thickness T5 of the second solder layer 40A was 2.0 μm to 3.0 μm before mounting and 1.0 μm to 2.0 μm after mounting, specifically 2.5 μm before mounting and 1.5 μm after mounting.

[0112] In the soldered submount 10A of this embodiment, openings 33 are formed at the outer peripheral edge of the first solder layer 30A. The openings 33 are areas where the first solder layer 30A is not present. In other words, the openings 33 are openings in the first solder layer 30A. A plurality of openings 33 are formed along the outer edge of the first solder layer 30A.

[0113] Each opening 33 is formed so as to cut out the outer peripheral edge of the first solder layer 30A. That is, in a plan view of the solder layer, each opening 33 is cut out so as to recede inward from the outer peripheral edge of the insulating member 11. Specifically, in a plan view of the first solder layer 30A, the opening 33 is formed so as to recess a portion of the side of the first solder layer 30A. In this embodiment, the shape of the opening 33 formed in one side of the first solder layer 30A is triangular. As an example, in a plan view of the first solder layer 30A, the shape of the opening 33 formed in one side of the first solder layer 30A is an isosceles triangle in which the bottom of the opening 33 (the point furthest back from the side) forms a right apex angle. Furthermore, in a plan view of the first solder layer 30A, the shape of the opening 33 formed in the corner of the first solder layer 30A is an isosceles triangle formed so as to be chamfered. The first solder layer 30A having the openings 33 can be formed by lifting off the solder using a resist.

[0114] By forming the openings 33 in the first solder layer 30A, the first metal film 12 is exposed through the openings 33. Therefore, due to the presence of multiple openings 33 intermittently at the outer peripheral edge of the first solder layer 30A, there is a portion on the outer edge of the lower surface (bottom surface) of the first metal film 12 where first regions 34a where the first solder layer 30A is present and second regions 34b where the first solder layer 30A is not present are alternately present. In other words, multiple first regions 34a and multiple second regions 34b exist on the outer edge of the first metal film 12. The outer edge of the lower surface of the first metal film 12 at the openings 33 is the second region 34b.

[0115] The openings 33 may be present on all four sides of the first solder layer 30A, or on one, two, or three of the four sides. Therefore, the second regions 34b corresponding to the openings 33 may also be present on all four sides of the outer edge of the first metal film 12, or on one, two, or three of the four sides. In this embodiment, the openings 33 and the second regions 34b are formed on all four sides of the first solder layer 30A and the first metal film 12.

[0116] All of the openings 33 formed in the first solder layer 30A include those in which a plurality of openings 33 are periodically arranged. The openings 33 correspond to the second regions 34b in which the first solder layer 30A is not present, and therefore all of the second regions 34b present on the outer edge of the lower surface of the first metal film 12 include those in which a plurality of second regions 34b are periodically arranged.

[0117] The plurality of periodically-spaced openings 33 may be present on all four sides of the first solder layer 30A, or on one, two, or three of the four sides. In other words, the plurality of periodically-spaced second regions 34b may be present on all four sides of the outer edge of the lower surface of the first metal film 12, or on one, two, or three of the four sides.

[0118] Furthermore, the periodically-spaced openings 33 (second regions 34b) may be all of the openings 33 (second regions 34b) on one side, or may be some of all of the openings 33 (second regions 34b) on one side. In this way, the periodically-spaced openings 33 (second regions 34b) only need to be present on at least a portion of the entire periphery of the first solder layer 30A or the first metal film 12.

[0119] In addition, the periodic presence of multiple openings 33 (second regions 34b) does not only mean that multiple openings 33 (second regions 34b) are present at regular intervals, but also means that multiple openings 33 (second regions 34b) are present at regular intervals.

[0120] Next, a method for manufacturing the semiconductor laser device 1 using the soldered submount 10A will be described with reference to Fig. 1 to Fig. 4, Fig. 14, etc., and with reference to Fig. 16. Fig. 16 is a flow chart showing a method for manufacturing the semiconductor laser device 1 according to the embodiment.

[0121] First, the soldered submount 10A is placed on the base 3 of a stem with electrode terminals, which is made up of the base 2 to which the lead pins 4 and base 3 are attached, as shown in Figures 1 and 2 (step S11). At this time, the soldered submount 10A is placed on the base 3 so that the first solder layer 30A faces the base 3. Specifically, the soldered submount 10A is placed so that the first solder layer 30A is in contact with the base 3.

[0122] Next, the semiconductor laser 20 is mounted on the soldered submount 10A shown in Fig. 14 (step S12). Specifically, the semiconductor laser 20 is mounted on the second solder layer 40A of the soldered submount 10A. In this embodiment, the semiconductor laser 20 is mounted on the soldered submount 10A in a junction-down manner.

[0123] Next, the solder on the soldered submount 10A is melted by heating (step S13). Specifically, the soldered submount 10A is heated while the semiconductor laser 20 placed on the soldered submount 10A is pressed down from above. As an example, the soldered submount 10A is heated at a temperature of 330°C for about 10 seconds.

[0124] In this way, by heating the soldered submount 10A, the first solder layer 30A and the second solder layer 40A melt, thereby bonding the base 3 and the submount 10 together with the solder of the melted first solder layer 30A, and bonding the semiconductor laser 20 and the submount 10 together with the solder of the melted second solder layer 40A.

[0125] In this embodiment, the first solder layer 30A and the second solder layer 40A are made of the same solder material, so that the semiconductor laser 20, the submount 10, and the base 3 can be bonded together at the same time.

[0126] Furthermore, in this embodiment, the soldered submount 10A is heated while pressing down the semiconductor laser 20, so that the submount 10 is pressed against the base 3. In other words, the submount 10 applies a pressing force against the base 3. Therefore, the pressing force of the submount 10 causes the molten solder of the first solder layer 30A present between the submount 10 and the base 3 to protrude from the submount 10. Specifically, the molten solder of the first solder layer 30A spreads outward from the outer edge of the submount 10, and also spreads in the thickness direction of the submount 10. In other words, the molten solder of the first solder layer 30A adheres to the submount on the base 3. 10 The submount 10 extends horizontally along the installation surface, and also extends above the base 3 on the side of the submount 10.

[0127] At this time, the molten solder of the first solder layer 30A will overflow from the outer edge of the submount 10, starting from the area where solder is present at the outer peripheral end of the first solder layer 30A. However, in this embodiment, since openings 33 are formed intermittently at the outer peripheral end of the first solder layer 30A, there will be areas at the outer peripheral end of the first solder layer 30A where solder is present and areas where solder is not present.

[0128] 14, first regions 34a where the first solder layer 30A is present and second regions 34b where the first solder layer 30A is not present are alternately present at the outer edge of the lower surface of the first metal film 12. For this reason, the molten solder of the first solder layer 30A overflows from the outer edge of the submount 10, starting from the first region 34a where the first solder layer 30A is present.

[0129] As this solder extrusion progresses, the length of the second region 34b along the outer edge of the submount 10 where the first solder layer 30A is not present becomes smaller (i.e., the opening 33 is gradually filled with solder). However, the surface tension of the molten solder prevents the molten solder from extruding from the submount 10 through the second region 34b (opening 33) where the unmelted first solder layer 30A is not present. In other words, the solder is prevented from extruding from the outer edge of the submount 10 outside the region where the unmelted first solder layer 30A is located on the outer edge of the submount 10. As a result, the solder of the first solder layer 30A that has extruded from the outer edge of the submount 10 forms the extrusion region 31 shaped as shown in FIGS. 3 and 4. Specifically, after cooling, the molten solder of the first solder layer 30A becomes the solder 30 with multiple protrusions 31a formed in the extrusion region 31, as shown in FIGS. 3 and 4.

[0130] 14, the openings 33 in the first solder layer 30A include a plurality of openings 33 that are periodically arranged. That is, the second regions 34b (regions where the first solder layer 30A is not present) that exist at the outer edge of the lower surface of the first metal film 12 include a plurality of second regions 34b that are periodically arranged. As a result, the protruding region 31 of the solder 30 has a plurality of protruding portions 31a that are periodically arranged. The periodic presence of the plurality of protruding portions 31a means that the solder 30 protrudes without being biased, and the submount 10 can be joined to the base 3 without tilting.

[0131] The tilt of the submount 10 can be evaluated by measuring the state of the multiple protrusions 31a on the solder 30. Therefore, at this time, an inspection may be performed to determine whether the submount 10 is good or bad by evaluating the tilt of the submount 10. Details of this inspection method will be described later.

[0132] Next, the semiconductor laser 20 and the lead pins 4 are wire-bonded (step S14). Specifically, one of the pair of electrodes of the semiconductor laser 20 and one of the pair of lead pins 4 are connected by a gold wire 7, and the second metal film 13 of the submount 10 and the other of the pair of lead pins 4 are connected by the gold wire 7.

[0133] Next, the cap 5 is welded to the base 2 (step S15). Specifically, after the semiconductor laser 20 and the lead pin 4 are wire-bonded, UV irradiation and ozone cleaning are performed, and then the cap 5 is placed on the base 2, and the base 2 and the cap 5 are joined by welding.

[0134] This completes the TO-can package type semiconductor laser device 1 shown in FIGS.

[0135] A preferred embodiment of the first solder layer 30A in the soldered submount 10A will now be described with reference to FIG.

[0136] First, as shown in (b) of Figure 14, in a plan view of the first solder layer 30A, the length (d2, d5 in Figure 14) of the first region 34a at the outer edge of the lower surface of the first metal film 12 is preferably 20 μm or more and 200 μm or less.

[0137] The first region 34a is the region where the first solder layer 30A exists, and is therefore the region from which the molten solder overflows from the submount 10 when the solder of the first solder layer 30A melts.

[0138] If the length of the first region 34a is too long, when the solder of the first solder layer 30A melts and spreads outside the submount 10, the boundary between the submount 10 and the solder protrusion region (protrusion 31a) may become too long. In other words, the width of the base of the protrusion 31a of the solder 30 may become too long, and the amount of solder protruding from the protrusion 31a may become too large in some areas. If the base width of the protrusion 31a becomes too long, the symmetry of the protrusion region 31 (protrusion 31a) of the solder 30 may be lost, and the submount 10 joined with the solder 30 may tilt. Therefore, the length of the first region 34a is preferably 200 μm or less. This prevents the base width of the protrusion 31a from becoming too long, thereby preventing the submount 10 from tilting.

[0139] On the other hand, if the length of the first region 34a is too short, when the solder of the first solder layer 30A melts, the molten solder is less likely to spill out of the first region 34a of the submount 10, which may limit the destination of the molten solder. In this case, the solder with its limited destination spreads to the second region 34b (the region where the first solder layer 30A is not present). The molten solder may spill out of the submount 10 from the second region 34b, rather than from the first region 34a (the region where the first solder layer 30A is present). If the solder spills out of the second region 34b in this way, the symmetry of the spilling region 31 (protrusion 31a) of the solder 30 is lost, and the submount 10 joined by the solder 30 may tilt. Therefore, it is preferable that the length of the first region 34a be 20 μm or more. This makes it possible to prevent the molten solder from spilling out of the second region 34b, and to prevent the submount 10 from tilting.

[0140] As an example, in a rectangular submount 10, the length d2 of the first region 34a on the long side is 80 μm, and the length d5 ​​of the first region 34a on the short side is 80 μm. In this embodiment, the length d2 of the first region 34a on the long side and the length d5 ​​of the first region 34a on the short side are the same, but this is not limited to this. In this case, it is preferable that the length d5 ​​of the first region 34a on the short side be greater than the length d2 of the first region 34a on the long side (d5>d2). This makes it possible to equalize the amount of protrusion 31a protruding from the long side and the amount of protrusion 31a protruding from the short side.

[0141] Furthermore, as shown in (b) of Figure 14, in a plan view of the first solder layer 30A, the length (d1, d4 in Figure 14) of the second region 34b at the outer edge of the lower surface of the first metal film 12 is preferably 20 μm or more and 200 μm or less.

[0142] In this way, by setting the length of the second region 34b to 200 μm or less, when the solder of the first solder layer 30A melts and spills out of the submount 10 from the multiple first regions 34a, the solder (multiple protrusions 31a) spilling out of each of the multiple first regions 34a can be prevented from becoming too discrete. If the spilled solder becomes discrete, the number of spilled points decreases, and differences in the size of the individual protrusions 31a tend to disrupt the uniformity of the amount of spilled solder. Therefore, if the spilled solder does not become excessively discrete, tilting of the submount 10 joined with the solder 30 can be prevented. Furthermore, by setting the length of the second region 34b to 20 μm or more, when the solder of the first solder layer 30A melts and spills out of the submount 10 from the multiple first regions 34a, the solder spilled out of each of the multiple first regions 34a can be prevented from coming into contact and integrating. In other words, it is possible to prevent two adjacent protrusions 31a from coming into contact with each other and becoming one with each other.

[0143] As an example, in a rectangular submount 10, the length d1 of the second region 34b on the long side is 60 μm, and the length d4 of the second region 34b on the short side is 50 μm. In this embodiment, the length d1 of the second region 34b on the long side is different from the length d4 of the second region 34b on the short side, but they may be the same. Furthermore, when the length d1 of the second region 34b on the long side is different from the length d4 of the second region 34b on the short side, it is preferable that the length d1 of the second region 34b on the long side is greater than the length d5 ​​of the second region 34b on the short side, as in this embodiment. This allows the amount of protrusion of the protrusion 31a from the long side to be equal to the amount of protrusion of the protrusion 31a from the short side.

[0144] 14(b), in a plan view of the first solder layer 30A, the length (d3, d6 in FIG. 14) between one end of the opening 33 at the outer peripheral edge of the insulating member 11 and the other end opposite the one end is preferably 20 μm or more and 100 μm or less. In other words, the recession amount of the opening 33 cut out so as to recess inward from the outer peripheral edge of the insulating member 11 is preferably 20 μm or more and 100 μm or less.

[0145] In this way, by setting the recession amount of the opening 33 to 20 μm or more, when the solder of the first solder layer 30A melts, it is possible to prevent the molten solder from spilling out of the second region 34b (region where the first solder layer 30A is not present) to the outside of the submount 10. Furthermore, by setting the recession amount of the opening 33 to 100 μm or less, it is possible to prevent the occurrence of a portion (void) where no solder is present between the submount 10 and the base 3 in the inner region of the submount 10 (insulating member 11). This makes it possible to prevent the occurrence of voids in the solder 30, thereby preventing a decrease in the heat dissipation performance of the heat generated by the semiconductor laser 20.

[0146] As an example, in a rectangular submount 10, the recessed length d3 from the long side of the opening 33 is 30 μm, and the recessed length d6 from the short side of the opening 33 is 30 μm. In this embodiment, the lengths d3 and d6 are the same, but the lengths d3 and d6 may be different.

[0147] Furthermore, as shown in (b) of Figure 14, on one side of the outer edge of the rectangular submount 10 (insulating member 11), the length of the first region 34a at the center of the side is preferably shorter than the length of the first region 34a at the part closest to the end of the side.

[0148] When the submount 10 is bonded to the base 3 and the semiconductor laser 20, a load is applied to the center of the semiconductor laser 20. If the first regions 34a along one side of the first solder layer 30A are all the same length and the second regions 34b are equally spaced, the size of the solder (protrusions 31a) protruding from the submount 10 decreases toward the edge of the submount 10. Therefore, by making the length of the first regions 34a located in the center of one side of the first solder layer 30A shorter than the length of the first regions 34a located closest to the edge, the size of the solder (protrusions 31a) protruding from the submount 10 can be made uniform. This makes it possible to uniform the amount of the protrusions 31a protruding from the submount 10 along one side of the submount 10. Therefore, tilting of the submount 10 bonded with the solder 30 can be suppressed.

[0149] In this case, it is preferable that the lengths of the multiple first regions 34a on one side of the first solder layer 30A gradually increase from the center to the end. For example, in (a) of Fig. 14, there are five first regions 34a on the long side of the first solder layer 30A, and the length of the central first region 34a is the shortest (e.g., 40 µm), the lengths of the two first regions 34a on both ends are the longest (e.g., 80 µm), and the lengths of the two intermediate first regions 34a between the central first region 34a and the first regions 34a on both ends are intermediate between them (e.g., 60 µm).

[0150] In the soldered submount 10A of the present embodiment, the shape of the opening 33 formed in the first solder layer 30A (opening shape) is triangular, but the shape is not limited to this.

[0151] For example, the opening 33 formed in the first solder layer 30A may have a semicircular shape, as in the soldered submount 10B shown in Fig. 17. By making the opening 33 semicircular in shape, lift-off of the solder resist can be facilitated.

[0152] 18, the opening 33 formed in the first solder layer 30A may be rectangular. By making the opening 33 rectangular in shape, as described below, when the soldered collective submount is divided to produce the soldered submount 10A, it is possible to suppress variations in the opening width due to misalignment during division, and it is possible to suppress variations in the elements of the soldered submount.

[0153] From the viewpoint of periodically forming the multiple protrusions 31a of the solder 30, it is preferable that the shape of the opening 33 of the first solder layer 30A is triangular. The resistance of the molten solder of the first solder layer 30A to overflowing outside the submount 10 depends on the shape of the opening 33. By forming the opening 33 in a triangular shape, the molten solder is less likely to fill the opening 33 and overflow from the second region 34b outside the submount 10 compared to when the opening 33 is semicircular or rectangular. As a result, the periodic protrusions 31a can be stably formed.

[0154] Furthermore, the position of the opening 33 in the first solder layer 30A is not limited to the position shown in FIG. 14(b).

[0155] For example, as in a soldered submount 10D shown in Fig. 19, the openings 33 in the first solder layer 30A may be formed only on the long side of the short and long sides. Since the submount 10 is prone to tilt in the short direction, even if the protrusions 31a are not formed on the short sides, as long as the protrusions 31a are formed periodically on the long sides, tilting of the submount 10 can be suppressed.

[0156] 20, the openings 33 in the first solder layer 30A do not have to be formed at the corners of the first solder layer 30A. Because the molten solder of the first solder layer 30A overflows from the corner farthest from the center, multiple protrusions 31a of uniform size can be formed overall even if openings 33 are not formed at the corners of the first solder layer 30A. Furthermore, when the soldered collective submount 10E is produced by dividing it, the absence of solder at the corners of the first solder layer 30A allows the divided surfaces to have a more linear shape.

[0157] Also, as in the soldered submount 10F shown in FIG. 21, at a plurality of corners of the first solder layer 30A, the corners where the openings 33 are formed and the openings 33 are formed are Not yet With this configuration, when the semiconductor laser 20 is mounted at a position offset from the center of the submount 10 in the width direction, the first region 34a can be easily disposed directly below the light-emitting point of the semiconductor laser 20, and in this configuration, the heat generated by the semiconductor laser 20 can be dissipated more efficiently.

[0158] In Figures 19 to 21, the openings 33 in the first solder layer 30A are not formed symmetrically left to right or top to bottom, but by using these soldered submounts 10F to fabricate semiconductor laser devices, it was possible to suppress the tilt of the submount 10.

[0159] [Soldered assembly submount] The above-mentioned soldered submounts 10A to 10F can be produced individually, but the soldered submounts 10A to 10F can also be produced by dividing one soldered collective submount into multiple pieces.

[0160] Such a soldered aggregate submount 10X will be described below with reference to Fig. 22. Fig. 22 is a diagram showing the configuration of a soldered aggregate submount 10X according to an embodiment. In Fig. 22, (a) is a top view, (b) and (c) are side views, and (d) is a rear view.

[0161] The soldered collective submount 10X is an assembly of soldered submounts. By dividing the soldered collective submount 10X into a plurality of pieces, a plurality of soldered submounts can be obtained.

[0162] As shown in FIG. 22, the soldered collective submount 10X includes a substrate 11X, a first metal film 12X, a second metal film 13X, a barrier film 14X, a first solder layer 30X, and a second solder layer 40X.

[0163] A lattice-shaped groove 50X is formed on the upper surface of the soldered collective submount 10X. The groove 50X is formed in the substrate 11X. Specifically, the groove 50X is formed so as to be dug from the upper surface to the lower surface of the substrate 11X.

[0164] The substrate 11X is an insulating substrate made of an insulating material. The substrate 11X serves as the insulating member 11 of the submount 10. Therefore, the substrate 11X is made of the same material as the insulating member 11.

[0165] The first metal film 12X is disposed on the lower surface of the substrate 11X. The first metal film 12X is formed across the entire lower surface of the substrate 11X, spanning the lattice-shaped grooves 50X. The first metal film 12X is made of the same material as the first metal film 12 of the submount 10.

[0166] The second metal film 13X is disposed on the upper surface of the substrate 11X. In a top view, the second metal film 13X is formed for each of the frames of the grid-like grooves 50X. The second metal film 13X is made of the same material as the second metal film 13 of the submount 10.

[0167] The barrier film 14X is formed on the upper surface of each second metal film 13X. In top view, the barrier film 14X is formed for each of the frames of the grid-like grooves 50X. The barrier film 14X is made of the same material as the barrier film 14 of the submount 10.

[0168] The first solder layer 30X is disposed on the underside of the substrate 11X. In this embodiment, the first solder layer 30X is disposed on the lower surface of the first metal film 12X. Like the first metal film 12X, the first solder layer 30X is formed across the entire lower surface of the first metal film 12X, spanning the lattice-shaped grooves 50X. The first solder layer 30X is made of the same material as the first solder layer 30A of the soldered submount 10A. In other words, the first solder layer 30X is made of the same material as the solder 30 of the semiconductor laser device 1.

[0169] The second solder layer 40X is disposed on the upper side of the substrate 11X. In this embodiment, the second solder layer 40X is disposed on the upper surface of each barrier film 14X. In top view, the second solder layer 40X is formed for each of the frames of the lattice-shaped grooves 50X. The second solder layer 40X is made of the same material as the second solder layer 40A of the soldered submount 10A. In other words, the second solder layer 40X is made of the same material as the solder 40 of the semiconductor laser device 1.

[0170] In the soldered collective submount 10X, a plurality of openings 33X are formed in the first solder layer 30X. Each of the plurality of openings 33X is a region where the first solder layer 30X is not present. The plurality of openings 33X are formed directly below the grooves 50X. The plurality of openings 33X are also formed periodically. Therefore, immediately below the grooves 50X, there are portions where the first solder layer 30X is not present periodically. Specifically, the plurality of openings 33X are formed so that a plurality of perforated straight lines (broken lines) intersect at right angles, corresponding to the lattice-shaped grooves 50X. Note that the shape of each opening 33X is, for example, rectangular. In this case, the plurality of openings 33X are arranged so that the rectangular corners of two adjacent openings 33X face each other.

[0171] By forming the openings 33X in the first solder layer 30X, the first metal film 12X is exposed from the openings 33X. Therefore, since a plurality of openings 33X are periodically formed in the first solder layer 30X directly below the grooves 50X, regions where the first solder layer 30X is present and regions where the first solder layer 30X is not present alternate periodically on the lower surface of the first metal film 12X.

[0172] Next, referring to Fig. 22, a method for fabricating a soldered submount 10A using the soldered aggregate submount 10X shown in Fig. 22 will be described with reference to Fig. 23. Fig. 23 is a flow chart showing a method for fabricating a soldered submount 10A according to an embodiment.

[0173] First, lattice-shaped grooves 50X are formed in the substrate 11X (step S21). Specifically, as shown in FIG. 22, the grooves 50X are formed by digging from the upper surface to the lower surface of the substrate 11X. The substrate 11X may be a diamond substrate, a SiC substrate, or an AlN substrate. In this case, the lattice-shaped grooves 50X can be formed in the substrate 11X by laser processing, rotary blade processing, or etching (wet etching, dry etching). The grooves 50X are formed in continuous straight lines, but may also be formed in dashed lines.

[0174] Next, a rear surface metal film is formed on the substrate 11X (step S22). Specifically, as shown in FIG. 22, a first metal film 12X is formed as the rear surface metal film on the lower surface of the substrate 11X. As an example, a three-layer stacked film of Ti / Pt / Au is formed by vapor deposition as the first metal film 12X. The first metal film 12X serves as a solder underlayer for the first solder layer 30X.

[0175] Next, rear surface solder is formed on the rear surface metal film (step S23). Specifically, as shown in Fig. 22, a first solder layer 30X is formed as rear surface solder on the lower surface of the first metal film 12X, which is the rear surface metal film. At this time, as shown in Fig. 22, the first solder layer 30X is formed having a plurality of openings 33X located directly below the lattice-shaped grooves 50X.

[0176] In this case, for example, a rear resist pattern is formed on the surface of the first metal film 12X, solder such as AuSn solder is formed by vapor deposition, and then the rear resist is peeled off, thereby forming a first solder layer 30X having a plurality of openings 33X.

[0177] Next, a surface metal film is formed on the substrate 11X (step S24). Specifically, as shown in FIG. 22, a second metal film 13X is formed as the surface metal film on the upper surface of the substrate 11X. As an example, a three-layer stacked film of Ti / Pt / Au is formed by vapor deposition as the second metal film 13X. The second metal film 13X serves as a solder underlayer for the second solder layer 40X.

[0178] Next, a barrier film 14X is formed on the surface metal film (step S25). Specifically, as shown in FIG. 22, the barrier film 14X is formed on the upper surface of the second metal film 13X, which is the surface metal film. As an example, a surface resist is patterned, a platinum film is formed by vapor deposition, and then the surface resist is peeled off. This allows the barrier film 14X to be formed for each frame of the grid-like grooves 50X.

[0179] Next, surface solder is formed on the barrier film 14X (step S26). Specifically, as shown in FIG. 22, a second solder layer 40X is formed as surface solder on the upper surface of the barrier film 14X. Specifically, a surface resist is patterned over the entire surface of the substrate 11X to cover the barrier film 14X, and solder such as AuSn solder is formed by vapor deposition, and then the surface resist is peeled off. This allows the second solder layer 40X to be formed in each frame of the grid-like grooves 50X.

[0180] As a result of the above, a soldered collective submount 10X having grooves 50X formed therein can be fabricated as shown in FIG.

[0181] Next, the soldered aggregated submount 10X is attached to an expanding sheet (step S27). The expanding sheet is a stretchable sheet with adhesive properties. Specifically, the soldered aggregated submount 10X is placed on the expanding sheet. This causes the soldered aggregated submount 10X to be attached to the expanding sheet by the adhesive layer of the expanding sheet.

[0182] Next, the grooves 50X of the soldered aggregated submount 10X are pressed to break it (step S28). Specifically, the grooves 50X are pressed from the rear surface of the expand sheet. As a result, the grooves 50X act as dividing lines, and the soldered aggregated submount 10X is divided along the grooves 50X. In this case, for example, the grooves 50X on the long side are pressed first, and then the grooves 50X on the short side are pressed. It is preferable to use a rubber member as the receiving base on the short side, and a stainless steel member as the receiving base on the long side.

[0183] At this time, the plurality of openings 33X located directly below the grooves 50X are also divided. Specifically, the rectangular openings 33X are divided into two, resulting in triangular openings 33.

[0184] In this way, by forming the lattice-shaped grooves 50X (division lines), the first solder layer 30X, which has a plurality of openings 33X, can be easily divided. In other words, if an attempt is made to divide the first solder layer 30X without forming the grooves 50X, the softness of the solder in the first solder layer 30X may affect the division of only the substrate 11X, and the first solder layer 30X may not be divided. In contrast, by forming the grooves 50X so as to face the plurality of openings 33X, the first solder layer 30X can be easily divided along the grooves 50X by breaking the soldered collective submount 10X.

[0185] The depth of the groove 50X is preferably between ¼ and ¾ of the thickness of the substrate 11X. If the depth of the groove 50X is less than ¼ of the thickness of the substrate 11X, the soldered aggregated submount 10X may not be separated properly. On the other hand, if the depth of the groove 50X exceeds ¾ of the thickness of the substrate 11X, the soldered aggregated submount 10X may crack when handled. In other words, the handleability of the soldered aggregated submount 10X may be reduced. In this embodiment, the depth of the groove 50X is set to approximately ½ of the thickness of the substrate 11X.

[0186] Next, the expand sheet is expanded and separated into individual soldered submounts 10A (step S29), whereby the soldered collective submount 10X divided along the grooves 50X is separated into a plurality of soldered submounts 10A.

[0187] Even if there are areas in the first solder layer 30X that are not divided when the soldered aggregate submount 10X is broken, the areas that were not divided when the soldered aggregate submount 10X was broken can be divided by expanding the expand sheet to which the soldered aggregate submount 10X is attached. This makes it possible to prevent the soldered submount 10A that should be separated from remaining unseparated (the occurrence of so-called twins).

[0188] Next, the soldered submount 10A is picked up (step S30). For example, the soldered submount 10A is picked up by pushing up each of the multiple separated soldered submounts 10A on the expand sheet from the back side of the expand sheet with a push-up pin.

[0189] By the above steps, a soldered submount 10A shown in Fig. 24 can be obtained. Specifically, a soldered submount 10A having a step portion 50 corresponding to the groove 50X can be obtained. In other words, the groove 50X of the soldered collective submount 10X is divided into two, and step portions 50 remain on the side of the soldered submount 10A.

[0190] A preferred embodiment of the first solder layer 30X in the soldered collective submount 10X will now be described with reference to FIG.

[0191] First, as shown in Fig. 22(d), the length (D2, D5 in Fig. 22) of the region where the first solder layer 30X exists along the longitudinal direction of the groove 50X directly below the longitudinal center of the groove 50X should be 200 µm or less. In other words, the distance between two adjacent openings 33X in the first solder layer 30X directly below the groove 50X should be 200 µm or less.

[0192] If the distance between two adjacent openings 33X is too long directly below the planned division point (grid-shaped groove 50X) of the soldered aggregate submount 10X, there will be a large amount of first solder layer 30X, making it difficult to separate the first solder layer 30X when expanding the expand sheet. However, by making the distance between two adjacent openings 33X 200 μm or less, the first solder layer 30X can be easily divided along the multiple openings 33X.

[0193] In the first solder layer 30X, the distance D2 between two adjacent openings 33X on the long side is preferably greater than the distance 52 between two adjacent openings 33X on the short side (D2>D5). This effectively prevents the submount 10 from tilting in the short direction. Considering the use of the submount after separation, D2 and D5 are preferably 20 μm or more and 200 μm or less.

[0194] 22(d), the length (D1, D4 in FIG. 22) of the region where the first solder layer 30X is not present along the longitudinal direction of the groove 50X directly below the longitudinal center of the groove 50X should be 20 μm or more. In other words, the length of the opening 33X along the groove 50X directly below the groove 50X should be 20 μm or more.

[0195] This reduces the area of ​​the first solder layer 30X, which can hinder division when dividing the soldered collective submount 10X, making it easier to divide the first solder layer 30X. Furthermore, considering the use of the submount after division, it is preferable that D1 and D4 be 20 μm or more and 200 μm or less.

[0196] 22(d), the distance (D6 in FIG. 22) between the center line of groove 50X and the edge of the area where first solder layer 30X is not present in the longitudinal direction of groove 50X should be 20 μm or more. In other words, the distance between the center line of groove 50X and the edge of opening 33X directly below groove 50X should be 20 μm or more.

[0197] When the soldered aggregate submount 10X is split by physical stress, the splitting plane is not necessarily perpendicular to the splitting principal surface, and the splitting plane may be misaligned. In this case, when the distance from the remaining thickness of the groove 50X to the surface of the substrate 11X is approximately 100 μm, the splitting plane is misaligned by less than 20 μm from the center line of the groove 50X. Therefore, by setting the distance D6 between the center line of the groove 50X and the edge of the opening 33X to 20 μm or more, the opening 33X is positioned at a distance of 20 μm or more from the center line of the groove 50X. This allows the edge of the splitting plane to overlap the opening 33X, preventing the first solder layer 30X from separating when the expand sheet is expanded (the occurrence of twins). If this distance D6 is too large, there will be less space available for mounting a semiconductor laser on the upper surface. Therefore, it is preferable that this distance D6 be 200 μm or less. Furthermore, when considering the manner in which the submount will be used after division, D6 is preferably twice the size of d3 and d6, ie, between 40 μm and 200 μm.

[0198] In the soldered aggregate submount 10X shown in FIG. 22, the openings 33X are not formed at the outer peripheral edge of the first solder layer 30X, but this is not limited thereto. For example, as in the soldered aggregate submount 10Y according to Modification 1 shown in FIG. 25, the openings 33X may be formed intermittently so as to be positioned directly below the lattice-shaped grooves 50X and also intermittently along the outer peripheral edge of the first solder layer 30X. In this case, each of the openings 33X positioned at the outer peripheral edge of the first solder layer 30X is formed so as to cut out the outer peripheral edge of the first solder layer 30X. FIG. 25 illustrates the configuration of the soldered aggregate submount 10Y according to Modification 1. In FIG. 25, (a) is a top view, (b) and (c) are side views, and (d) is a rear view.

[0199] The soldered aggregate submount 10Y shown in Fig. 25 can be fabricated in the same manner as the soldered aggregate submount 10X shown in Fig. 22. For example, the grooves 50X in the substrate 11X can be formed by irradiating them with laser light or the like.

[0200] Furthermore, the soldered aggregate submount 10Y shown in Figure 25 can be broken by applying physical stress to divide the soldered aggregate submount 10Y into multiple pieces along the grid-like grooves 50X, and then expanded with an expand sheet to separate the individual soldered submounts 10A.

[0201] In this case, when the soldered aggregate submount 10Y shown in Fig. 25 is used, not only is a soldered submount 10A obtained in which a step portion 50 is formed at both widthwise ends, but also a soldered submount 10A in which a step portion 50 is formed at only one of both widthwise ends, as shown in Fig. 26. In other words, an asymmetric soldered submount 10A can also be produced.

[0202] In this way, when the soldered aggregate submount 10X of FIG. 22 is divided to produce multiple soldered submounts 10A, the grooves 50X that serve as the dividing lines are formed not at the ends of the substrate 11X but at a point inward from the ends, which results in division loss, but the multiple soldered submounts 10A that are produced will be bilaterally symmetrical.

[0203] On the other hand, when the soldered aggregate submount 10Y of FIG. 25 is divided to produce multiple soldered submounts 10A, no division loss occurs because the grooves 50X that serve as dividing lines are not formed at the ends of the substrate 11X, but the multiple soldered submounts 10A produced will include some that are asymmetrical from left to right.

[0204] 22, multiple soldered submounts 10A are fabricated by forming dividing grooves 50X, but this is not limiting. That is, the soldered collective submount may be divided into multiple pieces without forming grooves 50X in the substrate 11X. For example, if the substrate 11X is a SiC substrate or an AlN substrate, the soldered collective submount can be divided into multiple pieces without forming grooves 50X in the substrate 11X.

[0205] In this case, the soldered aggregate submount can be divided into a plurality of pieces by the method shown in Fig. 27. Fig. 27 is a flow chart showing a modified method for manufacturing a soldered submount.

[0206] First, a rear surface metal film is formed on the substrate 11X (step S31). Specifically, similar to step S22 in FIG. 23, a first metal film 12X is formed as a rear surface metal film on the lower surface of the substrate 11X.

[0207] Next, rear surface solder is formed on the rear surface metal film (step S32). Specifically, similar to step S23 in Fig. 23, a first solder layer 30X is formed as rear surface solder on the lower surface of the first metal film 12X, which is the rear surface metal film. At this time, the first solder layer 30X is formed having a plurality of lattice-shaped openings 33X.

[0208] Next, a surface metal film is formed on the substrate 11X (step S33). Specifically, similar to step S24 in FIG. 23, a second metal film 13X is formed as a surface metal film on the upper surface of the substrate 11X.

[0209] Next, a barrier film 14X is formed on the surface metal film (step S34). Specifically, similar to step 25 of FIG. 23, the barrier film 14X is formed on the upper surface of the second metal film 13X, which is the surface metal film.

[0210] Next, surface solder is formed on the barrier film 14X (step S35). Specifically, similar to step 26 in FIG. 23, a second solder layer 40X is formed as surface solder on the upper surface of the barrier film 14X.

[0211] In this manner, a soldered collective submount without grooves 50X can be fabricated.

[0212] Next, the soldered collective submount is attached to the expandable sheet (step S36). Specifically, the soldered collective submount is placed on the expandable sheet in the same manner as in step S27 of FIG.

[0213] Next, the soldered aggregate submount is diced (step S37). Specifically, the soldered aggregate submount is diced from the rear surface of the expanded sheet. At this time, the soldered aggregate submount is diced along the plurality of openings 33X formed in a frame shape. As a result, the soldered aggregate submount is divided into a plurality of soldered submounts.

[0214] Next, the expand sheet is expanded and separated into individual soldered submounts (step S38). Specifically, the expand sheet is expanded in the same manner as in step 39 of FIG.

[0215] Next, the soldered submount is picked up (step S39). Specifically, the soldered submount is picked up in the same manner as in step 30 of FIG.

[0216] In this way, multiple soldered submounts can be obtained. Since the soldered submounts obtained in this manner do not have grooves 50X formed in the soldered collective submount, no step portions corresponding to the grooves 50X are formed.

[0217] As another modification, multiple soldered submounts 10A may be fabricated using a soldered aggregated submount 10Z shown in Fig. 28. Fig. 28 is a diagram showing the configuration of a soldered aggregated submount 10Z according to modification 2. In Fig. 28, (a) is a top view, (b) and (c) are side views, (d) is a rear view, and (e) is a cross-sectional view taken along line ee in (d).

[0218] In the soldered collective submount 10Z shown in FIG. 28, grooves 50X are not formed in the substrate 11X, and instead of the grooves 50X, lattice-shaped altered portions 50Z are formed inside the substrate 11X.

[0219] In this case, for example, a diamond substrate is used as the substrate 11X, and a lattice-shaped altered portion 50Z can be formed inside the substrate 11X by irradiating the substrate 11X with laser light in a lattice pattern. When the substrate 11X is irradiated with laser light, the diamond is melted by the laser light, and the inside of the substrate 11X is altered into an altered portion 50Z made of conductive carbon.

[0220] The soldered aggregate submount 10Z obtained in this manner can also be separated into multiple pieces along the lattice-shaped altered portions 50Z by applying physical stress and breaking it, and then separated into individual soldered submounts 10A by expanding it with an expand sheet. In this way, as shown in Fig. 29, a soldered submount 10A is produced in which the altered portions 50Z exist on the side surfaces of the insulating member 11 (substrate 11X).

[0221] As another modification, a soldered aggregate submount 10P shown in Fig. 30 may be used. Fig. 30 is a diagram showing the configuration of a soldered aggregate submount 10P according to modification 3. In Fig. 30, (a) is a rear view, and (b) is a cross-sectional view taken along line bb in (a).

[0222] 30, an opening 33P exposing the first metal film 12X is formed in the center of each of the frames of the plurality of lattice-shaped openings 33X located directly below the lattice-shaped grooves 50X (i.e., in a location that does not contribute to division). In other words, after division, there is an area in the center of the insulating member 11 that becomes the soldered submount 10A where the first solder layer 30X is not present.

[0223] By forming the openings 33P separately in a location other than directly below the grid-shaped grooves 50X, the contact area between the expand sheet and the soldered collective submount 10P can be reduced, thereby facilitating pick-up of the soldered submount 10A. In other words, the soldered submount 10A on the expand sheet can be easily pushed up by a push-up pin, improving pick-up performance. Furthermore, the openings 33P are formed at locations that do not intersect with the grooves 50X, which serve as dividing lines, and therefore do not affect the division of the soldered collective submount 10P. Forming multiple openings 33P further reduces the contact area between the expand sheet and the soldered collective submount 10P, further improving pick-up performance. Furthermore, the exposed portion of the openings is the first metal film 12X, which has high solder wettability, improving the spreading of solder during mounting.

[0224] Alternatively, a soldered aggregate submount 10Q shown in Fig. 31 may also be used. Fig. 31 is a diagram showing the configuration of a soldered aggregate submount 10Q according to Modification Example 4. In Fig. 31, (a) is a rear view, and (b) is a cross-sectional view taken along line bb in (a).

[0225] In the soldered aggregate submount 10Q shown in Figure 31, one or more strip-shaped openings 33Q parallel to the longitudinal direction of the submount 10 are formed in each of the lattice-shaped frames consisting of openings 33X through which multiple first metal films 12X are exposed (i.e., in locations that do not contribute to division).

[0226] This configuration improves the separability of the expanding sheet to which the soldered aggregated submount 10Q is attached when the sheet is expanded to separate the soldered aggregated submount 10A. Furthermore, the contact area between the expanding sheet and the soldered aggregated submount 10Q can be reduced, making it easier to pick up the soldered submounts 10A.

[0227] [Method for inspecting semiconductor laser devices] Next, a method for inspecting the semiconductor laser device 1 shown in FIGS. 1 and 2 will be described with reference to FIGS.

[0228] As described above, by placing the soldered submount 10A and the semiconductor laser 20 on the base 3 of the stem and heating them, the submount 10 and the base 3 can be joined with the solder 30. At this time, by measuring the state of the multiple protrusions 31a of the solder 30, the tilt (parallelism) of the submount 10 can be evaluated.

[0229] Specifically, by performing an appearance inspection using image recognition with a camera, the number, position, size, and / or shape of the multiple protrusions 31a of the solder 30 are measured, and the uniformity is evaluated, thereby evaluating the tilt of the submount 10. For example, if the number of protrusions 31a is the same on a pair of long sides or a pair of short sides of the submount 10, it can be determined that the state of the solder 30 on the left and right or on the top and bottom is uniform, and the submount 10 can be evaluated as not tilted. Note that semiconductor laser devices 1 can be sorted based on the degree of tilt of the submount 10.

[0230] The method for inspecting the semiconductor laser device 1 can be realized as an inspection step in the above-described method for manufacturing the semiconductor laser device 1. The method for inspecting the semiconductor laser device 1 can also be realized as a method for evaluating the semiconductor laser device 1.

[0231] (Variation) Although the semiconductor laser device and the like according to the present disclosure have been described above based on the embodiments, the present disclosure is not limited to the above-described embodiments.

[0232] For example, in the above embodiment, the semiconductor laser 20, the submount 10, and the base 3 are bonded simultaneously, but this is not limiting. For example, the semiconductor laser 20 may be mounted on the submount 10 in advance, and the submount 10 with the semiconductor laser 20 mounted thereon may be placed on the base 3 and heated to melt the first solder layer 30a, thereby bonding the submount 10 and the base 3 with the solder 30.

[0233] In addition, various modifications that can be made to the above-described embodiments by those skilled in the art, and modifications that do not deviate from the spirit of the present disclosure, are also possible. the above Form of implementation In a positive manner The present disclosure also includes embodiments realized by any combination of the components and functions described above. [Industrial Applicability]

[0234] The semiconductor laser device according to the present disclosure is useful as a light source for products in various fields, such as image display devices such as projectors, automotive parts such as in-vehicle headlamps, lighting fixtures such as spotlights, and industrial equipment such as laser processing devices. [Explanation of symbols]

[0235] 1. 1A Semiconductor laser device 2. Bass 3. Foundation 4 lead pins 5 Caps 6. Insulating material 7 Gold wire 8. Plate Glass 9. Adhesive 10 Submount 10a Submount area 10A, 10B, 10C, 10D, 10E, 10F Soldered Submount 10X, 10Y, 10Z, 10P, 10Q Soldered Assembly Submount 11 Insulating material 11X board 12, 12X 1st metal film 13, 13X second metal film 14, 14X barrier film 20 Semiconductor laser 30 solder 30A, 30X 1st solder layer 31 Overhang area 31a Convex part 31b Outer periphery 32 Non-extrusion area 33, 33X, 33P, 33Q opening 34a 1st area 34b Second area 40 solder 40A, 40X second solder layer 50 Step 50X Groove 50Z altered part

Claims

1. The base and a submount joined to the base via solder; a semiconductor laser mounted on the submount, When the submount is viewed from the side on which the semiconductor laser is mounted, the submount has the following structure: In the top view, the solder has a plurality of protrusions, the plurality of protrusions are formed on the base outside the submount, protrude in a direction opposite to the inside of the submount, and are periodically present around at least a portion of the entire circumference of the submount; Semiconductor laser device.

2. All of the plurality of protrusions are formed on the base outside the submount, protrude in a direction opposite to the inside of the submount, and are periodically arranged.

2. The semiconductor laser device according to claim 1.

3. At least a portion of the side is a long side.

3. The semiconductor laser device according to claim 1.

4. A base; a submount joined to the base via solder; a semiconductor laser mounted on the submount, When the submount is viewed from the side on which the semiconductor laser is mounted, the submount has the following structure: In the top view, the solder has a plurality of protrusions, Each of the plurality of protrusions is formed on the base outside the submount, protrudes in a direction opposite to the inside of the submount, and exists discontinuously around the entire periphery. Semiconductor laser device.

5. When viewed from the top, boundaries between the submount and the plurality of protrusions are periodically present.

5. The semiconductor laser device according to claim 1.

6. the solder has an outer periphery that protrudes beyond the outer edge of the submount; the plurality of protrusions protrude from the outer periphery in a direction opposite to the interior of the submount; 5. The semiconductor laser device according to claim 1.

7. At least one of the plurality of protrusions is located on an optical axis of the semiconductor laser when viewed from the top.

7. The semiconductor laser device according to claim 1.

8. a length of a boundary between the submount and one of the plurality of protrusions in the top view is not less than 20 μm and not more than 200 μm; 8. The semiconductor laser device according to claim 1, wherein the first and second electrodes are arranged parallel to each other.

9. When viewed from the top, the length of a portion of the solder where the outer edge of the solder does not protrude beyond the outer edge of the submount and the outer edge of the solder coincides with the outer edge of the submount is 200 μm or less.

9. The semiconductor laser device according to claim 1, wherein the first and second electrodes are arranged parallel to each other.

10. the submount has a rectangular shape in top view, When the number of the plurality of protrusions on one side of the rectangle is n and the amount of protrusion of each of the plurality of protrusions from the outer edge of the submount is Di (i is an integer, 1≦i≦n), On one side of the rectangle, the standard deviation of Di is 50% or less of the average value of Di.

10. The semiconductor laser device according to claim 1.

11. the submount has a rectangular shape in top view, The number of the plurality of protrusions on the long side of the rectangle is defined as m, a protrusion amount of each of the plurality of protrusions from the outer edge of the submount on a long side on the right side with respect to a direction in which laser light is emitted from the semiconductor laser is defined as DRi (i is an integer, 1≦i≦m), When the amount of protrusion of each of the plurality of protrusions from the outer edge of the submount on the left long side with respect to the direction of emission of laser light from the semiconductor laser is DLi (i is an integer, 1≦i≦m), The relationship of 1 / 3≦average value of DRi / average value of DLi≦3 is satisfied.

11. The semiconductor laser device according to claim 1.

12. the submount has a rectangular shape in top view, When the number of the plurality of convex portions on one side of the rectangle is n and the interval between the plurality of convex portions is Pi (i is an integer, 1≦i≦n−1), The standard deviation of Pi is less than or equal to 20% of the mean value of Pi.

12. The semiconductor laser device according to claim 1.

13. the submount has a rectangular shape in top view, On one side of the rectangle, the intervals between the plurality of protrusions include a group of first intervals whose standard deviation is within 10% and a group of second intervals whose standard deviation is within 10%; The second spacing is 1.5 times or less than the first spacing.

13. The semiconductor laser device according to claim 12.

14. the intervals between the plurality of protrusions on one side of the rectangle further include a group consisting of third intervals that are different from the first intervals and the second intervals and have a standard deviation of 10% or less; the third spacing is equal to or less than twice the first spacing; 14. The semiconductor laser device according to claim 13.

15. An insulating member; A metal film; a solder layer; the metal film is disposed on one surface of the insulating member, the solder layer is disposed on the one surface of the metal film; an outer edge of the one surface of the metal film has a portion where a first region where the solder layer is present and a second region where the solder layer is not present are alternately present; Submount.

16. a width of the surface on the one side of the insulating member is wider than a width of the surface on the opposite side of the insulating member; 16. The submount of claim 15.

17. a modified portion is present on a side surface of the insulating member; 16. The submount of claim 15.

18. In a plan view of the solder layer, the length of each of the first regions at the outer edge of the one surface of the metal film is 20 μm or more and 200 μm or less. The submount according to any one of claims 15 to 17.

19. In a plan view of the solder layer, the length of each of the second regions at the outer edge of the one surface of the metal film is 20 μm or more and 200 μm or less. The submount according to any one of claims 15 to 18.

20. An opening is formed at the outer peripheral edge of the solder layer, When viewed from above, the opening is cut out so as to recede inward from an outer peripheral end of the insulating member, an outer edge of the surface on the one side of the metal film in the opening is the second region; In a plan view of the solder layer, a length from one end of the opening at the outer peripheral end of the insulating member to the other end opposite to the one end is 20 μm or more and 100 μm or less. The submount according to any one of claims 15 to 19.

21. On one side of the outer edge of the insulating member, the length of the first region at the center of the side is shorter than the length of the first region at a portion closest to an end of the side. The submount according to any one of claims 15 to 20.

22. A submount assembly comprising: A substrate; A metal film; a solder layer; the metal film is disposed on one surface of the substrate, the solder layer is disposed on the one surface of the metal film; a lattice-shaped groove is formed on a surface of the collective submount opposite to the one side, or a lattice-shaped altered portion is formed inside the substrate, Immediately below the groove or the altered portion, there is a portion where the solder layer is not present periodically. Collective submount.

23. A submount assembly comprising: A substrate; A metal film; a solder layer; the metal film is disposed on one surface of the substrate, the solder layer is disposed on the one surface of the metal film; a lattice-shaped groove is formed on a surface of the collective submount opposite to the one side, or a lattice-shaped altered portion is formed inside the substrate, A plurality of openings are formed intermittently so as to be positioned in the lattice-shaped grooves or the altered portion. Collective submount.

24. a length of a region where the solder layer is present along the longitudinal direction at a position directly below a center portion of the groove or the altered portion in the longitudinal direction is 200 μm or less; 24. The submount assembly of claim 22 or 23.

25. a length of a region where the solder layer is not present along the longitudinal direction at a position directly below a center portion of the groove or the altered portion in the longitudinal direction is 20 μm or more and 200 μm or less; The submount assembly according to any one of claims 22 to 24.

26. In the longitudinal direction of the groove or the altered portion, the distance between the center line of the groove or the altered portion and the edge of the region where the solder layer is not present is 20 μm or more and 200 μm or less. The submount assembly according to any one of claims 22 to 25.

27. A method for inspecting a semiconductor laser device, comprising: The semiconductor laser device comprises: The base and a submount joined to the base via solder; a semiconductor laser mounted on the submount, When the submount is viewed from the side on which the semiconductor laser is mounted, the submount has the following structure: In the top view, the solder has a protruding region that protrudes beyond the outer edge of the submount; the protruding region has a plurality of protrusions each protruding outward, the semiconductor laser device inspection method includes: evaluating the tilt of the submount by measuring the states of the plurality of protrusions; A method for inspecting a semiconductor laser device.

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