Semiconductor device and method for manufacturing semiconductor device

Abstract

A semiconductor device (10) is provided with a semiconductor element (20), a submount (40), and a joining body (60). The semiconductor element (20) comprises an element body (22) and a first base electrode (24) that has a first joining surface (24a). The submount (40) comprises a base (42) and a second base electrode (44) that has a second joining surface (44a). The joining body (60) is an alloy that includes a plurality of metallic elements, is joined with the semiconductor element (20) in a first joining region (24b) of the first joining surface (24a), and is joined with the submount (40) in a second joining region (44b) of the second joining surface (44a). The semiconductor element (20) further includes an unjoined section (36) that is disposed outside the first joining region (24b) and that is formed from at least one metallic element among the plurality of metallic elements. The area of the first joining region (24b) is less than the area of the second joining region (44b).

Description

Semiconductor device and method for manufacturing the same

[0001] The present disclosure relates to a semiconductor device and a method for manufacturing a semiconductor device.

[0002] Conventionally, semiconductor devices have been known that include a semiconductor element such as a semiconductor laser chip and a submount for mounting the semiconductor element (see, for example, Patent Document 1 and Patent Document 2). In such semiconductor devices, the bonding surface of the semiconductor element is bonded to the bonding surface of the submount using a bonding material such as solder. In order to accurately position the semiconductor element at a predetermined position on the submount, a transfer device such as a collet is generally used to press the semiconductor element against the bonding material at a predetermined position on the submount, and the bonding material is then heated to melt and then cooled. As a result, the bonding material solidifies while in contact with the semiconductor element and the submount, allowing the semiconductor element to be bonded to the submount via the bonding material.

[0003] JP 2010-171047 A JP 2019-186328 A

[0004] However, when using the above method, the bonding material may protrude from between the bonding surfaces of the semiconductor element and the submount. As a result, the amount of bonding material between the bonding surfaces of the semiconductor element and the submount is reduced, which may result in insufficient bonding strength. Furthermore, when the bonding material protrudes, the semiconductor element may move from its predetermined position along with the bonding material.

[0005] The present disclosure has been made to solve such problems, and aims to provide a semiconductor device and the like that can suppress the protrusion of a bonding material from between the bonding surface of a semiconductor element and the bonding surface of a submount.

[0006] In order to achieve the above-mentioned object, the semiconductor device according to the present disclosure is a semiconductor device comprising a semiconductor element, a submount, and a bonding body, wherein the semiconductor element has an element body and a first base electrode disposed on the element body and having a first bonding surface bonded to the bonding body, the submount has a base and a second base electrode disposed on the base and having a second bonding surface bonded to the bonding body, the bonding body being an alloy containing multiple metal elements and bonded to the semiconductor element at a first bonding region on the first bonding surface and to the submount at a second bonding region on the second bonding surface, the semiconductor element further having a non-bonding portion disposed outside the first bonding region on the first bonding surface, the non-bonding portion having a different composition from the bonding body and being composed of at least one metal element of the multiple metal elements, and the area of ​​the first bonding region is smaller than the area of ​​the second bonding region.

[0007] In order to achieve the above object, a manufacturing method of a semiconductor device according to the present disclosure is a manufacturing method of a semiconductor device including a semiconductor element and a submount, wherein the semiconductor element has an element body, a first base electrode disposed on the element body and having a first bonding surface, and a first electrode pad disposed on the first bonding surface, and the submount has a base, a second base electrode disposed on the base and having a second bonding surface, and a second electrode pad disposed on the second bonding surface, and the manufacturing method of the semiconductor device includes a preparation step of preparing the semiconductor element and the submount having a bonding member disposed on the second electrode pad, a placement step of starting to place the semiconductor element on the bonding member by a transfer machine that moves the semiconductor element, thereby bringing the first electrode pad and the bonding member into contact with each other, a melting step of melting the bonding member, and a solidifying step of solidifying the bonding member, and in the melting step, a force with which the transfer machine presses the semiconductor element against the bonding member is determined based on a mass W [kg] of the semiconductor element and an average specific gravity ρ ｃ , gravitational acceleration G [m / s ２ ], and the specific gravity ρ of the joining member ｓ Using WG(ρ ｓ -ρ ｃ ) / ρ ｃ It is less than 10 times that.

[0008] According to the present disclosure, it is possible to provide a semiconductor device or the like that can suppress the protrusion of a bonding member from between the bonding surface of a semiconductor element and the bonding surface of a submount.

[0009] 1 is a top view showing the overall configuration of a semiconductor device according to an embodiment; FIG. 2 is a cross-sectional view showing the overall configuration of a semiconductor device according to an embodiment; FIG. 3 is a flowchart showing a flow of a manufacturing method of a semiconductor device according to an embodiment; FIG. 4 is a schematic graph showing an example of control of heater temperatures in a placing step, a melting step, and a solidification step of the manufacturing method of a semiconductor device according to an embodiment; FIG. 5 is a schematic cross-sectional view showing a semiconductor element prepared in a preparation step of the manufacturing method of a semiconductor device according to an embodiment; FIG. 6 is a schematic cross-sectional view showing a submount prepared in a preparation step of the manufacturing method of a semiconductor device according to an embodiment; FIG. 7 is a schematic top view showing the configuration of a submount according to an embodiment; FIG. 8 is a schematic cross-sectional view showing a placing step of the manufacturing method of a semiconductor device according to an embodiment; FIG. 9 is a schematic first cross-sectional view showing a melting step of the manufacturing method of a semiconductor device according to an embodiment; FIG. 10 is a schematic cross-sectional view showing a melting step of the manufacturing method of a semiconductor device according to an embodiment; 10A and 10B are schematic graphs showing examples of heater temperature control in the placing step, melting step, and solidification step of the semiconductor device manufacturing method according to Modification 1. 10B are schematic graphs showing examples of heater temperature control in the placing step, melting step, and solidification step of the semiconductor device manufacturing method according to Modification 2.

[0010] 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, and the arrangement and connection of the components shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0011] Furthermore, each figure is a schematic diagram and is not necessarily an exact representation. 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.

[0012] In this specification, the terms "above" and "below" do not refer to vertically above and below in absolute spatial recognition, but are used as terms defined by a relative positional relationship based on the stacking order in a stacked configuration. The terms "above" and "below" are used not only when two components are arranged with a gap between them and another component is present between them, but also when two components are arranged in contact with each other.

[0013] (Embodiment) A semiconductor device and a method for manufacturing the semiconductor device according to an embodiment will be described.

[0014] [1. Overall Configuration of Semiconductor Device] The overall configuration of a semiconductor device according to this embodiment will be described with reference to Figures 1 and 2. Figures 1 and 2 are a top view and a cross-sectional view, respectively, showing the overall configuration of a semiconductor device 10 according to this embodiment. Figure 2 shows a cross section of the semiconductor device 10 taken along line II-II in Figure 1. Each figure shows an X-axis, a Y-axis, and a Z-axis that are orthogonal to one another. The X-axis, the Y-axis, and the Z-axis are in a right-handed Cartesian coordinate system.

[0015] As shown in FIG. 2 , the semiconductor device 10 includes a semiconductor element 20 , a submount 40 , and a bonded body 60 .

[0016] The semiconductor element 20 is an element that includes a semiconductor layer and has electrodes connected to the semiconductor layer. Although the semiconductor element 20 is not particularly limited, in this embodiment, the semiconductor element 20 is a semiconductor light-emitting element that emits light. More specifically, the semiconductor element 20 is a semiconductor laser element that emits laser light. As shown in FIG. 2 , the semiconductor element 20 is disposed in the Z-axis direction with respect to the submount 40.

[0017] The semiconductor element 20 has an element body 22 , a first base electrode 24 , and a non-bonding portion 36 .

[0018] The element body 22 is the main body of the semiconductor element 20 and includes a semiconductor layer. The element body 22 includes, for example, a GaAs substrate, an n-type semiconductor layer, an active layer, and a p-type semiconductor layer. In this embodiment, a recess 22d is formed on the surface of the element body 22 facing the submount 40. The recess 22d has a flat bottom. Note that, here, "flat" does not necessarily mean a completely flat state, but also includes a substantially flat state. For example, a state in which the error in the depth of the recess 22d at each position relative to the average depth of the recess 22d is within about 10% is also referred to as "flat." The dimension of the element body 22 in the X-axis direction is, for example, 120 μm to 150 μm, and the dimension in the Y-axis direction (i.e., the longitudinal direction of the semiconductor element 20) is, for example, 260 μm to 280 μm.

[0019] The first base electrode 24 is disposed on the element body 22 and has a first bonding surface 24a to be bonded to the bonding body 60. In this embodiment, the first base electrode 24 is a metal film disposed in a recess 22d formed in the element body 22. The first base electrode 24 is formed of a metal material that easily adheres to the element body 22. The first base electrode 24 may be, for example, a single-layer film or a multilayer film formed of at least one of Ti, Cr, Ni, Pd, and Pt. In this embodiment, the first base electrode 24 has a Ti film with a thickness of 100 nm that contacts the element body 22 and a Pt film with a thickness of 150 nm that contacts the Ti film. In this embodiment, the surface of the Pt film corresponds to the first bonding surface 24a. The first base electrode 24 may be disposed on the substrate side of the element body 22 or on the back side (semiconductor layer side) of the element body 22 relative to the substrate.

[0020] The non-bonding portion 36 is a metal portion disposed outside the first bonding region 24b on the first bonding surface 24a of the first base electrode 24. Here, the first bonding region 24b is a region on the first bonding surface 24a to which the bonded body 60 is bonded. The non-bonding portion 36 has a different composition from the bonded body 60 and is composed of at least one metal element among the multiple metal elements contained in the bonded body 60. The non-bonding portion 36 surrounds the periphery of the first bonding region 24b. In this embodiment, the non-bonding portion 36 is an Au film with a film thickness of 200 nm.

[0021] The submount 40 is a member on which the semiconductor element 20 is mounted, and includes a base 42 and a second base electrode 44. In this embodiment, the submount 40 further includes an external electrode pad 48, as shown in FIG.

[0022] As shown in FIG. 2 , the base 42 is a member having a main surface 42 a on which the second base electrode 44 is disposed. The base 42 has, for example, a rectangular parallelepiped shape. In this embodiment, the base 42 is a Si substrate having a main surface 42 a with a length of each side of 300 μm. The material of the base 42 is not limited to Si. For example, a ceramic substrate, a polycrystalline substrate, a single crystal substrate, or the like made of a material such as alumina, AlN, SiC, or diamond can be used as the base 42.

[0023] The second base electrode 44 is disposed on the base 42 and has a second bonding surface 44a to be bonded to the bonded body 60. The second base electrode 44 is disposed on the main surface 42a of the base 42. The second base electrode 44 is formed of a metal material that easily adheres to the base 42. The second base electrode 44 may be, for example, a single-layer film or a multi-layer film formed of at least one of Ti, Cr, Ni, Pd, and Pt. In this embodiment, the second base electrode 44 has a Ti film with a thickness of 100 nm that contacts the base 42 and a Pt film with a thickness of 150 nm that contacts the Ti film. In this embodiment, the surface of the Pt film corresponds to the second bonding surface 44a.

[0024] 1 is an electrode pad for connecting external wiring. When viewed from above on the second bonding surface 44a of the second base electrode 44, the external electrode pad 48 is disposed in a region of the second bonding surface 44a that is located outside the semiconductor element 20. In other words, the external electrode pad 48 is disposed in a region of the second bonding surface 44a that is not covered by the semiconductor element 20. The external electrode pad 48 is electrically connected to the first base electrode 24 via the second base electrode 44 and the bonding body 60. In this embodiment, the external electrode pad 48 is an Au film with a thickness of 200 nm.

[0025] The bonding material 60 is an alloy containing multiple metal elements, and bonds the semiconductor element 20 and the submount 40. The bonding material 60 is bonded to the semiconductor element 20 in a first bonding region 24b of the first bonding surface 24a, and is bonded to the submount 40 in a second bonding region 44b of the second bonding surface 44a. The bonding material 60 is, for example, AuSn solder.

[0026] 1, the area of ​​the first bonding region 24b is smaller than the area of ​​the second bonding region 44b. The dimension of the first bonding region 24b in the X-axis direction parallel to the first bonding surface 24a is smaller than the dimension of the second bonding region 44b in the X-axis direction, and the dimension of the first bonding region 24b in the Y-axis direction parallel to the first bonding surface 24a and perpendicular to the X-axis direction is smaller than the dimension of the second bonding region 44b in the Y-axis direction.

[0027] In this embodiment, the area of ​​the first bonding surface 24a is smaller than the area of ​​the second bonding region 44b. The dimension of the first bonding surface 24a in the X-axis direction is smaller than the dimension of the second bonding region 44b in the X-axis direction, and the dimension of the first bonding surface 24a in the Y-axis direction is smaller than the dimension of the second bonding region 44b in the Y-axis direction.

[0028] The area of ​​the second bonding region 44b is smaller than the area of ​​the semiconductor element 20 when viewed from above on the second bonding surface 44a. The dimension of the second bonding region 44b in the X-axis direction is smaller than the dimension of the semiconductor element 20 in the X-axis direction when viewed from above on the second bonding surface 44a, and the dimension of the second bonding region 44b in the Y-axis direction is smaller than the dimension of the semiconductor element 20 in the Y-axis direction when viewed from above on the second bonding surface 44a.

[0029] In this embodiment, as shown in FIG. 2 , the distance D1 from the narrowest portion 60w, which has the smallest cross-sectional area parallel to the second bonding surface 44a of the bonded body 60, to the first bonding surface 24a is smaller than the distance D2 from the narrowest portion 60w to the second bonding surface 44a. In the example shown in FIG. 2 , the narrowest portion 60w is located closer to the second bonding surface 44a than the surface of the non-bonded portion 36 (the lower surface in FIG. 2 ). However, the position of the narrowest portion 60w is not limited thereto. The distance from the narrowest portion 60w to the second bonding surface 44a may be equal to the distance from the surface of the non-bonded portion 36 to the second bonding surface 44a, for example. In other words, the narrowest portion 60w may be on the same plane as the surface of the non-bonded portion 36.

[0030] [2. Semiconductor Device Manufacturing Method] A semiconductor device manufacturing method according to this embodiment will be described with reference to FIGS. 3 to 13. FIG. 3 is a flowchart showing the flow of the semiconductor device 10 manufacturing method according to this embodiment. FIG. 4 is a schematic graph showing an example of heater temperature control during the placement process, melting process, and solidification process of the semiconductor device 10 manufacturing method according to this embodiment. FIGS. 5A and 5B are schematic cross-sectional views showing the semiconductor element 20 and the submount 40 prepared in the preparation process of the semiconductor device 10 manufacturing method according to this embodiment. FIGS. 7 to 13 are schematic cross-sectional views showing each process of the semiconductor device 10 manufacturing method according to this embodiment. FIGS. 5A, 5B, and 7 to 13 show cross sections of the semiconductor element 20, the submount 40, etc., at positions similar to those shown in FIG. 2. FIG. 6 is a schematic top view showing the configuration of the submount 40 according to this embodiment. FIG. 6 shows the submount 40 before the semiconductor element 20 is bonded thereto. Also, FIG. 6 shows the outline of the first electrode pad 30 of the semiconductor element 20 bonded to the submount 40 by a dashed line.

[0031] 3, first, the semiconductor element 20 shown in Fig. 5A and the submount 40 shown in Fig. 5B, in which the bonding member 60M is disposed on the second electrode pad 50, are prepared (preparation step S10). Here, as shown in Fig. 5A, the semiconductor element 20 has an element body 22, a first base electrode 24, and a first electrode pad 30.

[0032] The first electrode pad 30 is a metal film disposed on the first bonding surface 24a of the first base electrode 24. The central portion of the first electrode pad 30 is alloyed with the bonding member 60M disposed on the submount 40 to become part of the bonded body 60. On the other hand, the peripheral portion of the first electrode pad 30 is not alloyed. This non-alloyed peripheral portion of the first electrode pad 30 is referred to as the non-bonded portion 36. In this embodiment, the first electrode pad 30 is disposed in a recess 22d formed in the element body 22. Like the non-bonded portion 36, the first electrode pad 30 has a different composition from the bonded body 60 and is composed of at least one metal element from among the multiple metal elements contained in the bonded body 60. In this embodiment, the first electrode pad 30 is a 500 nm-thick Au film.

[0033] 5B, the submount 40 has a base 42, a second base electrode 44, and a second electrode pad 50. In the present embodiment, the submount 40 further has an external electrode pad 48, as shown in FIG.

[0034] 5B , the second electrode pad 50 is a metal film disposed on the second bonding surface 44a of the second base electrode 44. The second electrode pad 50 is alloyed with the bonding member 60M to become part of the bonded body 60. Like the first electrode pad 30, the second electrode pad 50 has a different composition from the bonded body 60 and is composed of at least one metal element among the multiple metal elements contained in the bonded body 60. In this embodiment, the second electrode pad 50 is an Au film with a film thickness of 200 nm.

[0035] The bonding member 60M is a member for bonding the semiconductor element 20 and the submount 40, and is disposed on the second electrode pad 50. As shown in FIG. 6 , in a top view of the second bonding surface 44a of the second base electrode 44, the area of ​​the bonding member 60M is smaller than the area of ​​the second electrode pad 50. The dimension of the bonding member 60M in the X-axis direction is smaller than the dimension of the second electrode pad 50 in the X-axis direction, and the dimension of the bonding member 60M in the Y-axis direction is smaller than the dimension of the second electrode pad 50 in the Y-axis direction. Furthermore, in a top view of the second bonding surface 44a, the area of ​​the first electrode pad 30 is larger than the area of ​​the bonding member 60M and smaller than the area of ​​the second electrode pad 50. The dimension of the first electrode pad 30 in the X-axis direction is larger than the dimension of the bonding member 60M in the X-axis direction and smaller than the dimension of the second electrode pad 50 in the X-axis direction. Furthermore, the dimension of the first electrode pad 30 in the Y-axis direction is larger than the dimension of the bonding member 60M in the Y-axis direction and smaller than the dimension of the second electrode pad 50 in the Y-axis direction. Furthermore, in a top view of the second bonding surface 44a, the area of ​​the second electrode pad 50 is smaller than the area of ​​the semiconductor element 20. The dimension of the second electrode pad 50 in the X-axis direction is smaller than the dimension of the semiconductor element 20 in the X-axis direction, and the dimension of the second electrode pad 50 in the Y-axis direction is smaller than the dimension of the semiconductor element 20 in the Y-axis direction. Specifically, the bonding member 60M has a width in the X-axis direction of 97 μm, a width in the Y-axis direction of 236 μm, and a thickness of 3.0 μm. The first electrode pad 30 has a width in the X-axis direction of 110 μm and a width in the Y-axis direction of 240 μm. The second electrode pad 50 has a width in the X-axis direction of 114 μm and a width in the Y-axis direction of 250 μm. The semiconductor element 20 has a width in the X-axis direction of 130 μm and a width in the Y-axis direction of 260 μm.

[0036] Furthermore, when viewed from above on the second bonding surface 44a, the bonding member 60M has a rectangular shape with the four corners removed. If the distance between the four corners of the bonding member 60M and the edge of the second electrode pad 50 is small, the four corners of the bonding member 60M are likely to protrude beyond the edge of the second electrode pad 50 when the bonding member 60M is melted in a subsequent process. However, by removing the four corners of the bonding member 60M, the bonding member 60M can be prevented from protruding beyond the second electrode pad 50. Specifically, the distance between the bonding member 60M and the edge of the second electrode pad 50 may be 30 μm or more. This prevents the melted bonding member 60M from protruding beyond the second electrode pad 50.

[0037] The bonding member 60M is disposed on the second electrode pad 50 by using a method such as vapor deposition. For example, AuSn solder can be used as the bonding member 60M.

[0038] Next, as shown in FIG. 3 , the semiconductor element 20 is placed on the bonding member 60M, thereby contacting the first electrode pads 30 with the bonding member 60M (placement step S20). In this embodiment, the placement step S20 includes the steps of: moving the semiconductor element 20 to the vicinity of the first electrode pads 30 by a transfer machine 90; placing the semiconductor element 20 on the bonding member 60M by the transfer machine 90, thereby contacting the first electrode pads 30 with the bonding member 60M; and releasing the semiconductor element 20 and returning it to its original position by the transfer machine 90. Here, the transfer machine 90 is a device that moves the semiconductor element 20, and may be, for example, a collet. The point at which the semiconductor element 20 comes into contact with the bonding member 60M is considered to be the start of placement, and the point at which the transfer machine 90 separates from the semiconductor element 20 is considered to be the end of placement. The semiconductor element 20 may be positioned relative to the submount 40 by, for example, taking images of the semiconductor element 20 and the submount 40 and using an image recognition technique, or by a mechanical method.

[0039] In this embodiment, preheating of the submount 40 and the bonding members 60M is initiated before the placement step S20, i.e., in the preparation step S10. As shown in FIG. 4 , in the placement step S20, the bonding members 60M are heated to a temperature lower than the melting point of the bonding members 60M. More specifically, in the placement step S20, the heater temperature is maintained at the same temperature as the preheating temperature in the preparation step S10, thereby continuously heating the bonding members 60M at a temperature lower than the melting point of the bonding members 60M. This maintains the temperature of the bonding members 60M below the melting point of the bonding members 60M. To heat the bonding members 60M, for example, the lower surface (the surface behind the main surface 42a) of the base 42 of the submount 40 may be placed on a heater. In the example shown in FIG. 4 , the heater temperature in the placement step S20 is maintained at 150°C, which is lower than the melting point of the bonding members 60M (the melting point of AuSn solder, 280°C). By performing preheating in this manner, it is possible to shorten the time required for further heating in the melting step S30 following the placing step S20, thereby shortening the time required for manufacturing the semiconductor device 10. For example, in the case of equipment that requires 0.010 seconds to raise the temperature by 1°C, the time required for heating can be shortened by 1.25 seconds by setting the preheating temperature to 150°C, which is 125°C higher than room temperature (25°C).

[0040] 3, the bonding members 60M are melted (melting step S30). In the present embodiment, in the melting step S30, the bonding members 60M are heated to a temperature higher than the melting point of the bonding members 60M. In the example shown in FIG. 4, the temperature of the heater is increased to 360° C., thereby melting the bonding members 60M.

[0041] In the melting step S30, the force with which the transfer machine 90 presses the semiconductor element 20 against the bonding material 60M is controlled so that the semiconductor element 20 is not buried in the melted bonding material 60M. For example, if the semiconductor element 20 is a semiconductor laser element whose main component is GaAs, the average specific gravity ρ of the semiconductor element 20 is controlled by the transfer machine 90. ｃ However, the specific gravity ρ of the joining member 60M ｓBecause the area of ​​the bonding member 60M is smaller than the area of ​​the semiconductor element 20 when the semiconductor element 20 is not pressed against the bonding member 60M, the semiconductor element 20 floats on the molten bonding member 60M. Therefore, when the area of ​​the bonding member 60M is smaller than the area of ​​the semiconductor element 20 when viewed from above on the second bonding surface 44a as in the present embodiment, even if the semiconductor element 20 is placed on the molten bonding member 60M, the bonding member 60M will not protrude outside the semiconductor element 20 unless the semiconductor element 20 is pressed against the bonding member 60M.

[0042] Furthermore, if the force pressing the semiconductor element 20 against the bonding member 60M is equal to or less than the force corresponding to the difference in specific gravity between the semiconductor element 20 and the bonding member 60M, the semiconductor element 20 will not be buried in the molten bonding member 60M. The force corresponding to the difference in specific gravity between the semiconductor element 20 and the bonding member 60M is calculated by multiplying the mass W [kg] of the semiconductor element 20 by the gravitational acceleration G [m / s ２ ], WG(ρ ｓ -ρ ｃ ) / ρ ｃ Therefore, the force with which the transfer machine 90 presses the semiconductor element 20 against the bonding member 60M is expressed as WG(ρ ｓ -ρ ｃ ) / ρ ｃ When the temperature is below 100° C., the molten bonding material 60M does not protrude outside the semiconductor element 20.

[0043] In reality, the surface tension of the molten bonding member 60M prevents the bonding member 60M from spreading laterally (in the X-axis and Y-axis directions in each drawing). The force of suppressing the spread caused by this surface tension depends on the wettability of the surface on which the bonding member 60M is placed, and the stronger the wettability of the surface, the weaker the force of suppressing the spread. For example, when the composition of the bonding member 60M is Au, ０．８ Sn ０．２ and when the surface of the second base electrode 44 is Pt, ρ ｃ = 5.3 x 10 ３ [kg / m ３ ], ρ ｓ = 1.5 x 10 ４ [kg / m ３ ], W = 1.8 × 10 －８ [kg], WG (ρ ｓ -ρ ｃ ) / ρ ｃ = 3.1 x 10－７ However, experimentally, the force pressing the semiconductor element 20 against the bonding member 60M was 3.1×10 －６ [N] or less, the bonding member 60M hardly protrudes outside the semiconductor element 20. In addition, when the force pressing the semiconductor element 20 against the bonding member 60M is 1.5×10 －６ [N] or less, the bonding member 60M does not protrude outside the semiconductor element 20. Therefore, the force pressing the semiconductor element 20 against the bonding member 60M is WG(ρ ｓ -ρ ｃ ) / ρ ｃ This can prevent the bonding member 60M from protruding. The force pressing the semiconductor element 20 against the bonding member 60M can be set to WG(ρ ｓ -ρ ｃ ) / ρ ｃ This makes it possible to more reliably prevent the joining member 60M from protruding.

[0044] In the present embodiment, in the melting step S30, the force with which the transfer machine 90 presses the semiconductor element 20 against the bonding member 60M is zero. As shown in Fig. 8, the transfer machine 90 may be separated from the semiconductor element 20. This makes it possible to more reliably prevent the bonding member 60M from protruding.

[0045] In order to explain the effect of the melting step S30 according to the present embodiment, a semiconductor device manufactured using a comparative melting step will be described with reference to Fig. 14. Fig. 14 is a schematic cross-sectional view showing the configuration of a semiconductor device 910 manufactured using the comparative melting step.

[0046] In the melting step of this comparative example, the semiconductor element 20 is melted to the joining member 60M by WG(ρ ｓ -ρ ｃ ) / ρ ｃ14 , the bonding member 60M protrudes from between the first electrode pad 30 (or the first base electrode 24) and the second electrode pad 50 (or the second base electrode 44) (i.e., the area where a line segment connecting any point on the first electrode pad 30 and any point on the second electrode pad 50 can exist). At the left end of the bonding member 60M in FIG. 14 , the side surface of the bonding member 60M protrudes in a convex shape from between the first electrode pad 30 and the second electrode pad 50. At the right end of the bonding member 60M in FIG. 14 , the bonding member 60M protrudes significantly to the outside of the first electrode pad 30. In this case, the amount of bonding member 60M between the bonding surfaces of the first electrode pad 30 and the second electrode pad 50 decreases, causing the thickness of the bonding member 60M to become thinner than a critical value, which may result in insufficient bonding strength. Furthermore, when the bonding member 60M protrudes in one direction, there is a risk that the semiconductor element 20 may move in that direction together with the bonding member 60M from a predetermined position.

[0047] In contrast, in the melting step S30 according to the present embodiment, the force pressing the semiconductor element 20 against the bonding member 60M is WG(ρ ｓ -ρ ｃ ) / ρ ｃ Therefore, a sufficient amount of the bonding member 60M can be secured between the bonding surfaces of the first electrode pad 30 and the second electrode pad 50 (for example, the thickness of the bonding member 60M can be secured to be 2 μm or more), so that the bonding member 60M can obtain sufficient bonding strength and can suppress movement of the semiconductor element 20.

[0048] In the melting step S30, when the bonding member 60M is heated from the submount 40 side, the temperature of the portion of the bonding member 60M close to the submount 40 exceeds the melting point, causing the bonding member 60M to melt (become liquid-phase), as shown in Fig. 8. This causes the portion of the bonding member 60M close to the submount 40 to stretch in the lateral direction. Note that in the state shown in Fig. 8, the portion of the bonding member 60M far from the submount 40 remains in a solid state.

[0049] 9, the liquid-phase bonding member 60M and the portion of the second electrode pad 50 that is in contact with the bonding member 60M begin to alloy, causing the Sn element of the bonding member 60M to diffuse into the second electrode pad 50, and the region having a composition of AuSn, i.e., the region of the bonding member 60M, expands.

[0050] 10 , when the heating is continued, the liquid-phase bonding member 60M spreads over the entire upper surface of the second electrode pad 50. That is, the area of ​​the lower surface of the bonding member 60M becomes equal to the area of ​​the upper surface of the second electrode pad 50. Furthermore, the area of ​​the bonding member 60M spreads toward the lower surface of the second electrode pad 50.

[0051] As heating continues, a portion of the upper portion of the bonding member 60M (the portion farther from the submount 40) also becomes liquid, as shown in FIG. 11 . The liquid bonding member 60M spreads laterally. Furthermore, alloying begins between the bonding member 60M and the portion of the first electrode pad 30 that contacts the bonding member 60M. This completes the electrical connection between the semiconductor element 20 and the submount 40.

[0052] As heating continues, the entire bonding member 60M, including its upper portion, becomes liquid, as shown in FIG. 12 . As a result, the upper portion of the bonding member 60M also spreads laterally. However, because the lower portion of the bonding member 60M has a higher temperature and is more fluid, the lower portion spreads more laterally than the upper portion. Furthermore, the surface tension of the liquid bonding member 60M suppresses the lateral spread. As shown in FIG. 12 , in this embodiment, the entire second electrode pad 50 is alloyed with the bonding member 60M. This allows the submount 40 and the bonding member 60M to be firmly bonded. Note that the outer region of the second electrode pad 50 does not alloy with the bonding member 60M and has low wettability to the bonding member 60M, so the bonding member 60M is less likely to spread.

[0053] Furthermore, the central portion of the first electrode pad 30 is alloyed with the bonding member 60M. This allows for a strong bond between the semiconductor element 20 and the bonding member 60M. The alloyed region corresponding to the central portion of the first electrode pad 30 is the first bonding region 24b where the bonding member 60M and the first bonding surface 24a of the first base electrode 24 are bonded. The non-bonding portion 36 located outside the central portion of the first electrode pad 30 is not alloyed with the bonding member 60M. When the bonding member 60M is AuSn, the non-bonding portion 36 does not contain Sn elements, and the alloy portion between the first electrode pad 30 and the bonding member 60M contains Sn elements.

[0054] By bonding the semiconductor element 20 to the bonding member 60M in this manner so that the non-bonded portion 36 is formed, it is possible to reliably prevent the bonding member 60M from protruding.

[0055] Furthermore, since the contact angle between the non-bonded portion 36 of the semiconductor element 20 and the molten bonding member 60M is maintained at a predetermined angle, the bonding member 60M has a constricted shape while it is melted.

[0056] Next, as shown in FIG. 3 , the joining members 60M are solidified (solidification step S40). In this embodiment, as shown in FIG. 4 , the heater temperature is lowered to cool the temperature of the joining members 60M to below the melting point of the joining members 60M. In the example shown in FIG. 4 , the heater temperature is cooled to 150° C. The joining members 60M are solidified in the above manner. By solidifying the joining members 60M in this manner, the joined body 60 is formed as shown in FIG. 13 . Note that, although the shape characteristics are generally maintained during solidification, depending on the solidification conditions of the joining members 60M, a constriction (narrowest portion 60w) may not be observed in the joined body 60 formed by solidifying the joining members 60M.

[0057] As described above, the semiconductor device 10 according to the present embodiment can be manufactured.

[0058] [3. Modifications of the Manufacturing Method of the Semiconductor Device] Methods of manufacturing the semiconductor device 10 according to Modifications 1 and 2 of the present embodiment will be described. The methods of manufacturing the semiconductor device 10 according to Modifications 1 and 2 differ from the method of manufacturing the semiconductor device according to the present embodiment described above in terms of the manner of preheating in the placing step S20. The methods of manufacturing the semiconductor device 10 according to Modifications 1 and 2 will be described below with reference to FIGS. 15 and 16, respectively, focusing on the differences from the method of manufacturing the semiconductor device 10 according to the present embodiment.

[0059] FIG. 15 is a schematic graph showing an example of heater temperature control in the mounting step S20, melting step S30, and solidification step S40 of the semiconductor device manufacturing method according to Modification 1. In the preparation step S10 described above, the preheating temperature was 150°C. In contrast, in the mounting step S20 according to Modification 1, as shown in FIG. 15 , after preheating at 150°C, the submount 40 carrying the bonding members 60M is heated to 360°C, which is higher than the melting point (280°C) of the bonding members 60M, to melt the bonding members 60M. Mounting is initiated and terminated in this state, and then the temperature is lowered to 200°C. In other words, in the mounting step S20 according to Modification 1, mounting is initiated with the bonding members 60M in a molten state. This allows the surface shape of the bonding members 60M to deform during mounting of the semiconductor element 20, so that the posture of the semiconductor element 20 after mounting is not affected by variations in the surface shape of the bonding members 60M before mounting. Furthermore, since the bonding member 60M is in a molten state when placement is completed, the contact area between the first electrode pad 30 and the bonding member 60M during placement increases, and the risk that the semiconductor element 20 will remain held on the transfer machine 90 side when the transfer machine 90 is separated from the semiconductor element 20 is reduced due to the influence of surface tension, etc.

[0060] 16 is a schematic graph showing an example of heater temperature control during the placing step S20, melting step S30, and solidifying step S40 of the semiconductor device manufacturing method according to Modification 2. In Modification 2, the time during which the transfer machine 90 presses the bonding members 60M via the semiconductor element 20 is longer than in Modification 1. In this case, the placing process ends when the temperature of the bonding members 60M has dropped and they have solidified. That is, in the placing step S20, the placing process ends when the bonding members 60M have solidified. In this case, the semiconductor element 20 and the solidified bonding members 60M are bonded together, further reducing the risk that the semiconductor element 20 will remain held by the transfer machine 90 when the transfer machine 90 is removed from the semiconductor element 20.

[0061] 4. Effects, etc. As described above, the semiconductor device 10 according to this embodiment includes a semiconductor element 20, a submount 40, and a bonding body 60. The semiconductor element 20 includes an element body 22 and a first base electrode 24 disposed on the element body 22 and having a first bonding surface 24a bonded to the bonding body 60. The submount 40 includes a base 42 and a second base electrode 44 disposed on the base 42 and having a second bonding surface 44a bonded to the bonding body 60. The bonding body 60 is an alloy containing multiple metal elements, and is bonded to the semiconductor element 20 at a first bonding region 24b of the first bonding surface 24a and is bonded to the submount 40 at a second bonding region 44b of the second bonding surface 44a. The semiconductor element 20 further includes a non-bonding portion 36 disposed outside the first bonding region 24b of the first bonding surface 24a, the non-bonding portion 36 having a different composition from the bonding body 60 and composed of at least one metal element of the multiple metal elements contained in the bonding body 60. The area of ​​the first bonding region 24b is smaller than the area of ​​the second bonding region 44b.

[0062] By bonding the semiconductor element 20 to the bonding member 60M in this manner so that the non-bonded portion 36 is formed outside the first bonding region 24b, the end of the bonding member 60M on the semiconductor element 20 side can be prevented from extending to the end of the first bonding surface 24a, and therefore the bonding body 60 can be prevented from protruding outward from the first bonding surface 24a.

[0063] Furthermore, in the semiconductor device 10, the area of ​​the first bonding surface 24a may be smaller than the area of ​​the second bonding region 44b, and the area of ​​the second bonding region 44b may be smaller than the area of ​​the semiconductor element 20 when viewed from above the second bonding surface 44a.

[0064] In this way, by making the area of ​​the first bonding surface 24a and the second bonding region 44b smaller than the area of ​​the semiconductor element 20 when viewed from above on the second bonding surface 44a, the bonding body 60 can be prevented from protruding outside the semiconductor element 20.

[0065] Furthermore, in the semiconductor device 10, the distance D1 from the narrowest portion 60w, which has the smallest cross-sectional area parallel to the second bonding surface 44a of the bonding body 60, to the first bonding surface 24a may be smaller than the distance D2 from the narrowest portion 60w to the second bonding surface 44a.

[0066] In this positional relationship, the cross section of the bonded body 60 has a shape close to a trapezoid with the second bonding surface side being wider. On the other hand, since the heat conduction range in thermal diffusion increases with the distance from the heat source, this shape of the bonded body 60 leads to high heat dissipation characteristics.

[0067] In the semiconductor device 10 , the entire bonding body 60 may be disposed inside the periphery of the semiconductor element 20 when the second bonding surface 44 a is viewed from above.

[0068] This prevents the bonded body 60 from protruding outside the semiconductor element 20 .

[0069] In the semiconductor device 10, the semiconductor element 20 may be a semiconductor light-emitting element.

[0070] In this embodiment, misalignment of the semiconductor element 20 can be suppressed, and therefore misalignment of the optical axis of the semiconductor element 20, which is a semiconductor light-emitting element, can be suppressed. In particular, when the semiconductor element 20 is a semiconductor laser element and is used as a point light source, the required specifications for optical axis position accuracy are often strict, and the effect of suppressing misalignment is useful. Furthermore, when the semiconductor laser element emits light laterally and is mounted junction-down, the bonded body 60 does not protrude outside the semiconductor laser element, and therefore the light emitted from the semiconductor laser element is not obstructed by the bonded body 60.

[0071] The manufacturing method of the semiconductor device 10 according to the present embodiment includes a preparation step S10 of preparing a semiconductor element 20 and a submount 40 having bonding members 60M disposed on second electrode pads 50, a placement step S20 of placing the semiconductor element 20 on the bonding members 60M using a transfer machine 90 that moves the semiconductor element 20, thereby bringing the first electrode pads 30 and the bonding members 60M into contact with each other, a melting step S30 of melting the bonding members 60M, and a solidifying step S40 of solidifying the bonding members 60M. In the melting step S30, the force with which the transfer machine 90 presses the semiconductor element 20 against the bonding members 60M is equal to or less than 10 times W (ρs - ρc) / ρc, where W is the mass W [kg] of the semiconductor element 20, the average specific gravity ρc, the gravitational acceleration G [m / s2], and the specific gravity ρs of the bonding members 60M.

[0072] As a result, the semiconductor element 20 is not pressed against the bonding member 60M with excessive force, and the semiconductor element 20 floats on the molten bonding member 60M. Therefore, the semiconductor element 20 is prevented from being buried in the bonding member 60M, and the bonding member 60M is prevented from protruding outside the semiconductor element 20.

[0073] Furthermore, in the melting step S30 of the method for manufacturing the semiconductor device 10, the force with which the transfer machine 90 presses the semiconductor element 20 against the bonding member 60M may be zero.

[0074] This reliably prevents the bonding member 60M from protruding outside the semiconductor element 20.

[0075] In the method for manufacturing the semiconductor device 10, the area of ​​the bonding member 60M may be smaller than the area of ​​the second electrode pad 50 when viewed from above the second bonding surface 44a.

[0076] This can prevent the bonding member 60M from protruding outside the second electrode pad 50.

[0077] Furthermore, in the manufacturing method of the semiconductor device 10, when viewed from above on the second bonding surface 44a, the area of ​​the first electrode pad 30 may be larger than the area of ​​the bonding member 60M and smaller than the area of ​​the second electrode pad 50, and the area of ​​the second electrode pad 50 may be smaller than the area of ​​the semiconductor element 20.

[0078] In this way, since the area of ​​the second electrode pad 50 on which the bonding member 60M is arranged is smaller than the area of ​​the semiconductor element 20, the bonding member 60M can be prevented from protruding outside the semiconductor element 20.

[0079] In the method for manufacturing the semiconductor device 10, the shape of the bonding member 60M may be a rectangle with the four corners removed when viewed from above the second bonding surface 44a.

[0080] If the bonding member 60M is rectangular, the four corners of the bonding member 60M are likely to protrude from the second electrode pad 50, but since the bonding member 60M does not have four corners, the bonding member 60M can be prevented from protruding from the second electrode pad 50.

[0081] In addition, in the melting step S30 of the manufacturing method of the semiconductor device 10, the center portion of the first electrode pad 30 may be alloyed with the bonding member 60M.

[0082] This allows the semiconductor element 20 and the bonding member 60M to be firmly bonded together.

[0083] Furthermore, in the melting step S30 of the manufacturing method of the semiconductor device 10, the non-bonding portion 36 located outside the center of the first electrode pad 30 does not need to be alloyed with the bonding member 60M.

[0084] By bonding the semiconductor element 20 to the bonding member 60M in this manner so that the non-bonded portion 36 is formed, it is possible to reliably prevent the bonding member 60M from protruding.

[0085] In addition, in the melting step S30 of the manufacturing method of the semiconductor device 10, the entire second electrode pad 50 may be alloyed with the bonding member 60M.

[0086] This allows the submount 40 and the bonding member 60M to be firmly bonded together.

[0087] In the placing step S20 of the method for manufacturing the semiconductor device 10, the bonding members 60M may be heated at a temperature lower than the melting point of the bonding members 60M.

[0088] In this way, by performing preheating in the placing step S20 before the melting step S30, the time required for further heating in the melting step S30 following the placing step S20 can be shortened, thereby shortening the time required for manufacturing the semiconductor device 10.

[0089] Furthermore, in the placing step S20 of the method for manufacturing the semiconductor device 10, the placing may be started in a state in which the bonding members 60M are melted.

[0090] This allows the surface shape of the bonding member 60M to be deformed when the semiconductor element 20 is placed, so that the posture of the semiconductor element 20 after placement is not affected by variations in the surface shape of the bonding member 60M before placement.

[0091] Furthermore, in the placing step S20 of the method for manufacturing the semiconductor device 10, the placing may be completed in a state where the bonding members 60M are solidified.

[0092] In this case, since the semiconductor element 20 and the solidified bonding material 60M are bonded together, the risk that the semiconductor element 20 will remain held on the transfer machine 90 side when the transfer machine 90 is removed from the semiconductor element 20 is reduced.

[0093] (Modifications, etc.) Although the semiconductor 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.

[0094] For example, although the semiconductor light emitting element is used as the semiconductor element in the above embodiment, other semiconductor elements may be used, such as a photodiode.

[0095] This disclosure also includes forms obtained by applying various modifications to the embodiments that a person skilled in the art would conceive, and forms realized by arbitrarily combining the components and functions in each embodiment within the scope of the present disclosure.

[0096] The semiconductor device etc. according to the present disclosure can be used in spatial multiplexing devices using semiconductor laser elements, thermally assisted hard disk devices using semiconductor laser elements, etc., which require high precision in the relative position between the submount and the semiconductor element.

[0097] 10, 910 Semiconductor device 20 Semiconductor element 22 Element body 22d Recess 24 First base electrode 24a First bonding surface 24b First bonding region 30 First electrode pad 36 Non-bonding portion 40 Submount 42 Base 42a Main surface 44 Second base electrode 44a Second bonding surface 44b Second bonding region 48 External electrode pad 50 Second electrode pad 60 Bonded body 60M Bonding member 60w Narrowest portion 90 Transfer machine

Claims

1. A semiconductor device comprising a semiconductor element, a submount, and a bonded body, The semiconductor device is An element body; a first base electrode disposed on the element body and having a first bonding surface to be bonded to the bonding body; The submount comprises: The base and a second base electrode disposed on the base and having a second bonding surface to be bonded to the bonded body; the bonding body is an alloy including a plurality of metal elements, and is bonded to the semiconductor element in a first bonding region of the first bonding surface, and is bonded to the submount in a second bonding region of the second bonding surface; the semiconductor element further includes a non-bonding portion disposed outside the first bonding region on the first bonding surface, the non-bonding portion having a composition different from that of the bonding body and being composed of at least one metal element among the plurality of metal elements; The area of ​​the first bonding region is smaller than the area of ​​the second bonding region; The distance from a narrowest portion of the bonded body, which has a smallest cross-sectional area parallel to the second bonded surface, to the first bonded surface is smaller than the distance from the narrowest portion to the second bonded surface. Semiconductor device.

2. The area of ​​the first bonding surface is smaller than the area of ​​the second bonding region; The area of ​​the second bonding region is smaller than the area of ​​the semiconductor element in a top view of the second bonding surface. The semiconductor device according to claim 1 .

3. When viewed from above at the second bonding surface, the entire bonding body is disposed inside the periphery of the semiconductor element. The semiconductor device according to claim 1 .

4. The semiconductor element is a semiconductor light emitting element that emits light. The semiconductor device according to claim 1 .

5. A method for manufacturing a semiconductor device including a semiconductor element and a submount, comprising the steps of: The semiconductor device is An element body; a first base electrode disposed on the element body and having a first bonding surface; a first electrode pad disposed on the first bonding surface; The submount comprises: The base and a second base electrode disposed on the base and having a second bonding surface; a second electrode pad disposed on the second bonding surface; The method for manufacturing a semiconductor device includes: a preparation step of preparing the semiconductor element and the submount having a bonding member disposed on the second electrode pad; a placing step of starting to place the semiconductor element on the bonding member by a transfer machine that moves the semiconductor element, thereby bringing the first electrode pads into contact with the bonding member; a melting step of melting the joining member; and a solidification step of solidifying the joining member, In the melting step, the force with which the transfer machine presses the semiconductor element against the joining member is determined by the mass W [kg] of the semiconductor element and the average specific gravity ρ ｃ , gravitational acceleration G [m / s ２ ], and the specific gravity ρ of the joining member ｓ Using WG(ρ ｓ -ρ ｃ ) / ρ ｃ is 10 times lower than A method for manufacturing a semiconductor device.

6. In the melting step, the force with which the transfer machine presses the semiconductor element against the joining member is zero. The method for manufacturing a semiconductor device according to claim 5 .

7. When viewed from above, the area of ​​the bonding member is smaller than the area of ​​the second electrode pad. The method for manufacturing a semiconductor device according to claim 5 or 6.

8. When viewed from above on the second bonding surface, an area of ​​the first electrode pad is larger than an area of ​​the bonding member and smaller than an area of ​​the second electrode pad; The area of ​​the second electrode pad is smaller than the area of ​​the semiconductor element. The method for manufacturing a semiconductor device according to claim 5 or 6.

9. When viewed from above at the second bonding surface, the bonding member has a rectangular shape with the four corners removed. The method for manufacturing a semiconductor device according to claim 5 or 6.

10. In the melting step, the center portion of the first electrode pad is alloyed with the bonding member. The method for manufacturing a semiconductor device according to claim 5 or 6.

11. In the melting step, the non-bonded portion located outside the central portion of the first electrode pad is not alloyed with the bonding material. The method for manufacturing a semiconductor device according to claim 10.

12. In the melting step, the entire second electrode pad is alloyed with the bonding member. The method for manufacturing a semiconductor device according to claim 5 or 6.

13. The semiconductor element is a semiconductor light emitting element that emits light. The method for manufacturing a semiconductor device according to claim 5 or 6.

14. In the placing step, the joining members are heated to a temperature lower than the melting point of the joining members. The method for manufacturing a semiconductor device according to claim 5 or 6.

15. In the placing step, the placing is started in a state in which the joining member is molten. The method for manufacturing a semiconductor device according to claim 5 or 6.

16. In the placing step, the placing is ended in a state where the joining member is solidified. The method for manufacturing a semiconductor device according to claim 15.