Semiconductor laser heat sink support, preparation method thereof and semiconductor laser

Abstract

The embodiment of the invention provides a semiconductor laser heat sink bracket, a preparation method thereof and a semiconductor laser. The preparation method comprises the following steps: providing a substrate; photoresist layers are formed on the front face and the back face of the substrate respectively, and the photoresist layers are patterned to form openings in the photoresist layers; electroplating in the opening to form a composite metal bonding pad; wherein during electroplating, a nano material is added into a metal electroplating solution, and the nano material is embedded in an electroplating metal layer so as to adjust the thermal expansion coefficient of the formed composite metal bonding pad, so that the thermal expansion coefficient of the composite metal bonding pad is used for being the same as or similar to the thermal expansion coefficient of a chip mounted on the composite metal bonding pad. The problem that stress generated by thermal expansion may damage the chip is avoided, and the service life of the device is prolonged. The thermal expansion coefficient of the composite metal bonding pad is adjusted by directly adding the nano material into the electroplating metal liquid, the preparation process is simple, and the operability is high.

Description

Technical Field

[0001] Embodiments of the present disclosure belong to the technical field of semiconductor lasers, and particularly relate to a semiconductor laser heat sink bracket, a preparation method thereof, and a semiconductor laser. Background Art

[0002] When a high-power semiconductor laser operates, due to the limitation of the electro-optical conversion efficiency, a large amount of heat will be generated. The thermal expansion coefficient matching of the die and the heat sink bracket material is a key issue. If the difference in the thermal expansion coefficients is large, the stress generated due to thermal expansion may damage the die and affect the device life.

[0003] In view of the above problems, it is necessary to propose a semiconductor laser heat sink bracket, a preparation method thereof, and a semiconductor laser with reasonable design and effective solution to the above problems. Summary of the Invention

[0004] Embodiments of the present disclosure aim to at least solve one of the technical problems existing in the prior art, and provide a semiconductor laser heat sink bracket, a preparation method thereof, and a semiconductor laser.

[0005] One aspect of the embodiments of the present disclosure provides a preparation method of a semiconductor laser heat sink bracket, and the method includes:

[0006] Providing a substrate;

[0007] Forming photoresist layers on the front and back surfaces of the substrate respectively, and patterning the photoresist layers to form openings on the photoresist layers;

[0008] Electroplating to form a composite metal pad in the opening; wherein, when electroplating, a nano material is added to the metal electroplating solution, and the nano material is embedded in the electroplated metal layer to adjust the thermal expansion coefficient of the formed composite metal pad, so that the thermal expansion coefficient of the composite metal pad is the same as or similar to the thermal expansion coefficient of the chip mounted on the composite metal pad.

[0009] Optionally, the added nano material includes at least one of carbon nano materials, boron nano materials, and oxide nano materials; wherein,

[0010] The content of the carbon nano material is 0.1% - 1%, the content of the boron nano material is 0.1% - 1%, and the content of the oxide nano material is 0.1% - 2%.

[0011] Optionally, the carbon nano material includes at least one of graphite, graphene, graphene nanotubes, graphyne, multi-walled carbon nanotubes, C60, activated carbon, carbon fiber, carbon black, glassy carbon, porous carbon materials, and carbon nanospheres.

[0012] Optionally, the boron nanomaterial includes at least one of borophene, boron nanowires, and boron nitride.

[0013] Optionally, the oxide nanomaterial includes at least one of Al2O3, CaTiO3, TiO2, and ZrO2.

[0014] Optionally, the metal electroplating solution includes sulfuric acid at 60 g / L to 220 g / L, copper sulfate at 60 g / L to 200 g / L, chloride ions at 60 ppm to 90 ppm, sodium polydithiopropanesulfonate at 0.001 g / L to 0.005 g / L, and polyethylene glycol at 0.5 g / L to 2 g / L.

[0015] Optionally, before forming the photoresist layers on the front and back of the substrate respectively, the method includes:

[0016] Forming seed layers on the front and back of the substrate respectively;

[0017] Forming the photoresist layers on the seed layers.

[0018] Optionally, after forming the composite metal pad, the method further includes:

[0019] Performing stripping, leveling, etching, electroless plating, and pre-cutting on the substrate in sequence to form the heat sink bracket.

[0020] Another aspect of the embodiments of the present disclosure provides a semiconductor laser heat sink bracket, which is prepared by using the preparation method described above.

[0021] Another aspect of the embodiments of the present disclosure provides a semiconductor laser, including the semiconductor laser heat sink bracket described above.

[0022] For the semiconductor laser heat sink bracket, its preparation method, and the semiconductor laser according to the embodiments of the present disclosure, in the preparation method of the semiconductor laser heat sink bracket, when electroplating, by adding nanomaterials to the metal plating solution, the nanomaterial particles are embedded in the electroplated metal layer to adjust the thermal expansion coefficient of the formed composite metal pad, so that the thermal expansion coefficient of the composite metal pad is the same as or similar to that of the chip mounted on the composite metal pad, avoiding the problem that the stress generated by thermal expansion may damage the chip and extending the device life. By directly adding nanomaterials to the electroplated metal solution, the nanomaterials grow inside the electroplated metal layer to form an integral composite metal pad. Through the internal stress design, the control of the thermal expansion coefficient is achieved, and the preparation process is simple and the operability is strong. Description of the Drawings

[0023] Figure 1 It is a schematic flowchart of a preparation method of a semiconductor laser heat sink bracket according to an embodiment in the embodiments of the present disclosure;

[0024] Figure 2 Schematic diagram of the structure of a heat sink bracket for a semiconductor laser in another embodiment of the present disclosure;

[0025] Figure 3 Schematic diagram of the structure of a semiconductor laser in another embodiment of the present disclosure;

[0026] Figure 4 Schematic diagram of the thermal expansion of the composite copper pad when heated in the embodiment of the present disclosure. Detailed implementation manners

[0027] To enable those skilled in the art to better understand the technical solutions of the embodiments of the present disclosure, the following further describes the embodiments of the present disclosure in detail with reference to the accompanying drawings and specific implementation manners.

[0028] As Figure 1 shown, one aspect of the embodiment of the present disclosure provides a method S100 for preparing a heat sink bracket for a semiconductor laser, and the preparation method S100 includes:

[0029] S110. Provide a substrate.

[0030] As Figure 2 shown, provide a substrate 110. In this embodiment, a gallium arsenide chip mounted on the heat sink bracket is taken as an example for illustration. Correspondingly, the substrate 110 can be selected as an AlN ceramic material (4.5×10 -6 °C -1 ) similar to the linear thermal expansion coefficient of the gallium arsenide chip (5.7×10 -6 °C -1 ).

[0031] S120. Form photoresist layers on the front and back surfaces of the substrate respectively, and pattern the photoresist layers to form openings on the photoresist layers.

[0032] Among them, before forming the photoresist layers on the front and back surfaces of the substrate respectively, the method includes:

[0033] First, form seed layers on the front and back surfaces of the substrate 110. Among them, the seed layer can include a titanium layer and a copper layer.

[0034] Second, form photoresist layers on the seed layers.

[0035] Specifically, form photoresist layers on the seed layers on the front and back surfaces of the substrate 110 respectively. Expose and develop the photoresist layers in sequence to pattern the photoresist layers and form openings on the photoresist layers, that is, form the pattern of the composite metal pad on the photoresist layer.

[0036] S130. Electroplate a composite metal pad within the opening; wherein, during electroplating, nano-materials are added to the metal electroplating solution, and the nano-materials are embedded in the electroplated metal layer to adjust the thermal expansion coefficient of the formed composite metal pad, so that the thermal expansion coefficient of the composite metal pad is the same as or similar to that of the chip mounted on the composite metal pad.

[0037] Specifically, a composite metal pad 120 is electroplated within the opening of the photoresist layer by using an electroplating process. Among them, during electroplating, nano-materials are added to the metal electroplating solution, and the nano-materials grow inside the electroplated metal layer to form an integral composite metal pad 120. Through the internal stress design, the thermal expansion coefficient of the formed composite metal pad is adjusted, so that the thermal expansion coefficient of the composite metal pad is the same as or similar to that of the chip 210 mounted on the composite metal pad 120 located on the front side of the substrate 110.

[0038] Among them, the added nano-materials include but are not limited to at least one of carbon nano-materials, boron nano-materials, and oxide nano-materials; wherein, the content of the carbon nano-materials is 0.1% - 1%, the content of the boron nano-materials is 0.1% - 1%, and the content of the oxide nano-materials is 0.1% - 2%.

[0039] In this embodiment, only a ball mill is needed to ball mill and the ordinary hot pressing method can be used to produce the corresponding nano-materials. The nano-materials are added by directly adding them to the electroplated metal solution. The electroplating equipment needs to fully circulate the electroplated metal solution to maintain the dispersion of the nano-material particles in the solution. The preparation process is simple and the operability is strong.

[0040] Exemplarily, in this embodiment, the carbon nano-materials include but are not limited to at least one of graphite, graphene, graphene nanotubes, graphyne, multi-walled carbon nanotubes, C60, activated carbon, carbon fiber, carbon black, glassy carbon, porous carbon materials, and carbon nanospheres.

[0041] Exemplarily, in this embodiment, the boron nano-materials include but are not limited to at least one of borene, boron nanowires, and boron nitride.

[0042] Exemplarily, in this embodiment, the oxide nano-materials include but are not limited to at least one of Al2O3, CaTiO3, TiO2, and ZrO2.

[0043] Exemplarily, in this embodiment, the metal electroplating solution includes but is not limited to sulfuric acid at 60 g / L to 220 g / L, copper sulfate at 60 g / L to 200 g / L, chloride ions at 60 ppm to 90 ppm, sodium polydithiopropane sulfonate at 0.001 g / L to 0.005 g / L, and polyethylene glycol at 0.5 g / L to 2 g / L. That is to say, the electroplating metal solution is a copper electroplating solution, and the formed composite metal pad 120 is a composite copper pad.

[0044] As shown in Table 1, the coefficient of thermal expansion of the formed composite metal pad 120 can be adjusted by adjusting the types and contents of various substances in the electroplating solution and the types and contents of the added nanomaterials, so that the coefficient of thermal expansion of the composite metal pad 120 is the same as or similar to that of the chip 210 mounted on the front side of the substrate 110.

[0045] In this embodiment, nanoparticles with a low coefficient of linear thermal expansion in the copper structure are used to make the coefficient of linear thermal expansion of the copper-carbon / boron / oxide composite material the same as that of the gallium arsenide chip, avoiding the stress generated by thermal expansion that may damage the chip.

[0046] Table 1 Coefficient of linear thermal expansion corresponding to each material

[0047]

[0048]

[0049] Exemplarily, after forming the composite metal pad, the method further includes:

[0050] The substrate 110 is successively subjected to film stripping, leveling, etching, electroless plating, and pre-cutting to form a heat sink bracket 100 as shown in Figure 2 Figure.

[0051] In the method for preparing a semiconductor laser heat sink bracket according to an embodiment of the present disclosure, during electroplating, nanomaterials are added to the metal plating solution, and the nanomaterial particles are embedded in the electroplated metal layer. During thermal expansion, the electroplated metal (copper) expands when heated, while the incorporated nanomaterials, due to their low coefficient of thermal expansion, pull the expanding electroplated metal (copper) in the opposite direction, thereby reducing the coefficient of thermal expansion of the overall composite metal pad. Furthermore, by adjusting the incorporation amount range of the nanomaterials, the coefficient of thermal expansion of the composite metal pad is controlled so that the coefficient of thermal expansion of the composite metal pad is the same as or similar to that of the chip mounted on the composite metal pad, avoiding the problem that the stress generated by thermal expansion may damage the chip and extending the device life. The method of directly adding nanomaterials to the electroplating metal solution to adjust the coefficient of thermal expansion of the composite metal pad has a simple preparation process and strong operability.

[0052] The preparation method of the semiconductor laser heat sink bracket according to the embodiments of the present disclosure will be specifically described below in conjunction with several embodiments. Among them, the detection of the linear thermal expansion coefficient of the composite material wire is carried out by the method of GB / T 16920-2015.

[0053] Embodiment 1

[0054] 1) Provide an AlN ceramic substrate with a size of 120 mm × 120 mm and a thickness of 0.38 mm. The thermal expansion coefficient of the AlN ceramic substrate is 4.5×10 -6 C -1 .

[0055] 2) Drill holes at corresponding positions on the AlN ceramic substrate with a hole diameter of 100 μm.

[0056] 3) Perform PVD sputtering on the AlN ceramic substrate to form a titanium layer and a copper layer on its surface to form a seed layer.

[0057] 4) Form a photoresist layer on the seed layer, and perform exposure and development on the photoresist layer in sequence to form an opening on the photoresist layer and form a pattern of a composite metal pad on the photoresist layer.

[0058] 5) Electroplate at the opening to form a composite copper pad. Among them, the electroplating metal solution includes 220 g / L of sulfuric acid, 60 g / L of copper sulfate, 80 ppm of chloride ions, 0.001 / L of sodium polydithiopropane sulfonate, and 1 g / L of polyethylene glycol. When electroplating, 1 w.t.% of h-BN nanosheets is added to the electroplating copper solution, and through the circulating jet flow and stirring of the electroplating tank body, the h-BN is uniformly dispersed in the plating solution, and the h-BN nanosheets grow inside the metallic copper to form a composite copper pad. The electroplating current density is 20 Ma / cm 2 .

[0059] 6) Perform film stripping, leveling, etching, chemical plating, and pre-cutting on the AlN ceramic substrate in sequence to form a heat sink bracket.

[0060] Among them, the formed composite copper pad is a copper-h-BN nanosheet composite material, and the linear thermal expansion coefficient of the copper-h-BN nanosheet material is 5.6×10 -6 C -1 . The linear thermal expansion coefficient of the formed composite copper pad is close to that of the gallium arsenide chip (5.7×10 -6 C -1 ), avoiding the problem that the stress generated by thermal expansion may damage the chip and prolonging the device life.

[0061] Such as Figure 4As shown in the figure, when the composite copper pad is heated, the copper material A expands outward due to heat, while the added nanomaterial B expands less or does not expand when heated, restricting the thermal expansion of copper, so that the overall composite copper pad material exhibits a smaller coefficient of thermal expansion. In addition, the resistivity of the composite pad, by testing 100% of the vias on the entire board, is ≤ 5 mΩ, which is the same as that of the traditional pure copper pad (resistance ≤ 5 mΩ).

[0062] Example 2

[0063] 1) Provide an AlN ceramic substrate with a size of 120 mm × 120 mm and a thickness of 0.38 mm. The coefficient of thermal expansion of the AlN ceramic substrate is 4.5×10 -6 C -1 .

[0064] 2) Drill holes at corresponding positions on the AlN ceramic substrate with a hole diameter of 100 μm.

[0065] 3) Perform PVD sputtering on the AlN ceramic substrate to form a titanium layer and a copper layer on its surface to form a seed layer.

[0066] 4) Form a photoresist layer on the seed layer, and perform exposure and development on the photoresist layer in sequence to form openings on the photoresist layer and form the pattern of the composite metal pad on the photoresist layer.

[0067] 5) Electroplate at the openings to form a composite copper pad. Among them, the electroplating metal solution contains 160 g / L of sulfuric acid, 100 g / L of copper sulfate, 90 ppm of chloride ions, 0.003 / L of sodium polydisulfide propane sulfonate, and 2 g / L of polyethylene glycol. 1 w.t.% of graphene is added to the electroplating copper solution during electroplating. Through the circulating jet flow and stirring of the electroplating tank body, the graphene is evenly dispersed in the plating solution, and the graphene grows inside the metallic copper to form a composite copper pad. The electroplating current density is 20 Ma / cm 2 .

[0068] 6) Perform stripping, leveling, etching, electroless plating, and pre-cutting on the AlN ceramic substrate in sequence to form a heat sink bracket.

[0069] Among them, the formed composite copper pad is a copper-graphene composite material, and the linear coefficient of thermal expansion of the composite copper-graphene material is 5.0×10 -6 C -1 . The linear coefficient of thermal expansion of the formed composite copper pad is close to that of the gallium arsenide chip (5.7×10 -6 C -1 ), avoiding the problem that the stress generated by thermal expansion may damage the chip and extending the device life; in addition, the resistivity of the composite pad, by testing 100% of the vias on the entire board, is ≤ 5 mΩ, which is the same as that of the traditional pure copper pad.

[0070] Example 3

[0071] 1) Provide an AlN ceramic substrate with a size of 120 mm × 120 mm and a thickness of 0.38 mm.

[0072] 2) Drill holes at corresponding positions on the AlN ceramic substrate with a hole diameter of 100 μm.

[0073] 3) Perform PVD sputtering on the AlN ceramic substrate to form a titanium layer and a copper layer on its surface to form a seed layer.

[0074] 4) Form a photoresist layer on the seed layer, and perform exposure and development on the photoresist layer in sequence to form an opening on the photoresist layer and form a pattern of a composite metal pad on the photoresist layer.

[0075] 5) Electroplate at the opening to form a composite copper pad. Among them, the electroplating metal solution contains 60 g / L of sulfuric acid, 160 g / L of copper sulfate, 70 ppm of chloride ions, 0.002 / L of sodium polydithiopropane sulfonate, and 0.5 g / L of polyethylene glycol. When electroplating, 0.8 w.t.% of graphene and 0.1 w.t.% of borophene are added to the electroplating copper solution. Through the circulating jet flow and stirring of the electroplating tank body, graphene and borophene are uniformly dispersed in the plating solution, and graphene and borophene grow inside the metallic copper to form a composite copper pad. The electroplating current density is 20 Ma / cm 2 .

[0076] 6) Perform film stripping, leveling, etching, chemical plating, and pre-cutting on the AlN ceramic substrate in sequence to form a heat sink bracket.

[0077] Among them, the formed composite copper pad is a copper-borophene-graphene composite material, and the linear thermal expansion coefficient of the composite copper-borophene-graphene material is 4.5×10 -6 °C -1 . The linear thermal expansion coefficient of the formed composite copper pad is close to that of the gallium arsenide chip (5.7×10 -6 °C -1 ), avoiding the problem that the stress generated by thermal expansion may damage the chip and prolonging the device life; in addition, the resistivity of the composite pad, through testing 100% of the through holes on the whole board, is ≤5 mΩ, which is the same as that of the traditional pure copper pad.

[0078] Example 4

[0079] 1) Provide an AlN ceramic substrate with a size of 120 mm × 120 mm and a thickness of 0.38 mm.

[0080] 2) Drill holes at corresponding positions on the AlN ceramic substrate with a hole diameter of 100 μm.

[0081] 3) Subject the AlN ceramic substrate to PVD sputtering to form a titanium layer and a copper layer on its surface to form a seed layer.

[0082] 4) Form a photoresist layer on the seed layer, and successively perform exposure and development on the photoresist layer to form openings in the photoresist layer and form a pattern of a composite metal pad on the photoresist layer.

[0083] 5) Electroplate at the openings to form composite copper pads. Among them, the electroplating metal solution contains 200 g / L of sulfuric acid, 200 g / L of copper sulfate, 80 ppm of chloride ions, 0.005 / L of sodium polydisulfide propane sulfonate, and 0.5 g / L of polyethylene glycol. In the same manner as in the previous embodiment, 0.5 w.t. % of h-BN is added to the electroplating copper solution during electroplating, and h-BN grows inside the metallic copper to form composite copper pads. The electroplating current density is 20 Ma / cm 2 。

[0084] 6) Successively perform stripping, leveling, etching, electroless plating, and pre-cutting on the AlN ceramic substrate to form a heat sink bracket.

[0085] Among them, the formed composite copper pads are copper-h-BN composite materials, and the linear thermal expansion coefficient of the composite copper-h-BN material is 6.8×10 -6 C -1 , which can be used for the thermal expansion coefficient materials of other chip materials such as aluminum-based silicon carbide (6.5 - 9.5×10 -6 C -1 ).

[0086] Example 5

[0087] 1) Provide an AlN ceramic substrate, the size of the substrate is 120 mm × 120 mm, and the thickness is 0.38 mm.

[0088] 2) Drill holes at corresponding positions on the AlN ceramic substrate, and the hole diameter is 100 μm.

[0089] 3) Subject the AlN ceramic substrate to PVD sputtering to form a titanium layer and a copper layer on its surface to form a seed layer.

[0090] 4) Form a photoresist layer on the seed layer, and successively perform exposure and development on the photoresist layer to form openings in the photoresist layer and form a pattern of a composite metal pad on the photoresist layer.

[0091] 5) Electroplate at the opening to form a composite copper pad. Among them, the electroplating metal solution contains 100 g / L of sulfuric acid, 150 g / L of copper sulfate, 80 ppm of chloride ions, 0.002 / L of sodium polydisulfide propane sulfonate, and 0.5 g / L of polyethylene glycol. When electroplating, add 0.1 w.t.% of h-BN (hexagonal boron nitride) to the electroplating copper solution, and h-BN grows inside the metallic copper to form a composite copper pad. The electroplating current density is 20 mA / cm 2 .

[0092] 6) Perform film stripping, leveling, etching, electroless plating, and pre-cutting on the AlN ceramic substrate in sequence to form a heat sink bracket.

[0093] Among them, the formed composite copper pad is a copper-h-BN composite material, and the linear thermal expansion coefficient of the composite material copper-h-BN is 9.2×10 -6 °C -1 and can be used for the thermal expansion coefficient materials of other chip materials such as aluminum-based silicon carbide (6.5 - 9.5×10 -6 °C -1 ).

[0094] Example 6

[0095] 1) Provide an AlN ceramic substrate with the substrate size of 120 mm×120 mm and the thickness of 0.38 mm.

[0096] 2) Drill holes at corresponding positions on the AlN ceramic substrate with the hole diameter of 100 μm.

[0097] 3) Perform PVD sputtering on the AlN ceramic substrate to form a titanium layer and a copper layer on its surface to form a seed layer.

[0098] 4) Form a photoresist layer on the seed layer, and perform exposure and development on the photoresist layer in sequence to form an opening on the photoresist layer and form the pattern of the composite metal pad on the photoresist layer.

[0099] 5) Electroplate at the opening to form a composite copper pad. Among them, the electroplating metal solution contains 220 g / L of sulfuric acid, 60 g / L of copper sulfate, 80 ppm of chloride ions, 0.001 / L of sodium polydisulfide propane sulfonate, and 1 g / L of polyethylene glycol. When electroplating, add 2 w.t.% of Al2O3 to the electroplating copper solution, and Al2O3 grows uniformly inside the metallic copper to form a composite copper pad. The electroplating current density is 20 mA / cm 2 .

[0100] 6) Perform film stripping, leveling, etching, electroless plating, and pre-cutting on the AlN ceramic substrate in sequence to form a heat sink bracket.

[0101] Among them, the formed composite copper pad is a copper-Al2O3 composite material, and the linear thermal expansion coefficient of the composite material is 9.1×10 -6 C -1 It can be used as a thermal expansion coefficient material for other chip materials such as aluminum-based silicon carbide (6.5 - 9.5×10 -6 C -1 ), avoiding the problem that the stress generated by thermal expansion may damage the chip and extending the device life.

[0102] Comparative Example 1

[0103] 1) Provide an AlN ceramic substrate with a size of 120 mm × 120 mm and a thickness of 0.38 mm. The thermal expansion coefficient of the AlN ceramic substrate is 4.5×10 -6 C -1 .

[0104] 2) Drill holes at corresponding positions on the AlN ceramic substrate with a hole diameter of 100 μm.

[0105] 3) Subject the AlN ceramic substrate to PVD sputtering to form a titanium layer and a copper layer on its surface to form a seed layer.

[0106] 4) Form a photoresist layer on the seed layer, and sequentially perform exposure and development on the photoresist layer to form an opening on the photoresist layer and form a pattern of the composite metal pad on the photoresist layer.

[0107] 5) Electroplate to form a copper pad at the opening. Among them, the electroplating metal solution includes 220 g / L of sulfuric acid, 60 g / L of copper sulfate, 80 ppm of chloride ions, 0.001 / L of sodium polydithiopropane sulfonate, and 1 g / L of polyethylene glycol. The electroplating current density is 20 Ma / cm 2 .

[0108] 6) Subject the AlN ceramic substrate to stripping, leveling, etching, chemical plating, and pre-cutting in sequence to form a heat sink bracket.

[0109] Among them, the linear thermal expansion coefficient of the formed copper pad is 17.6×10 -6 C -1 , it can be seen that without introducing the nanomaterials of the present invention, the linear thermal expansion coefficients of the final copper pad and the gallium arsenide chip (5.7×10 -6 C -1 ) have a large difference. During the thermal expansion process, the thermal expansion mismatch between the copper pad and the chip may cause stress concentration, thereby damaging the chip and affecting the reliability and life of the device.

[0110] Comparative Example 2

[0111] 1) Provide an AlN ceramic substrate with a size of 120 mm × 120 mm and a thickness of 0.38 mm.

[0112] 2) Drill holes at corresponding positions on the AlN ceramic substrate with a hole diameter of 100 μm.

[0113] 3) Perform PVD sputtering on the AlN ceramic substrate to form a titanium layer and a copper layer on its surface to form a seed layer.

[0114] 4) Form a photoresist layer on the seed layer, and sequentially perform exposure and development on the photoresist layer to form an opening on the photoresist layer and form a pattern of a composite metal pad on the photoresist layer.

[0115] 5) Electroplate at the opening to form a composite copper pad. Among them, the electroplating metal solution contains 220 g / L of sulfuric acid, 60 g / L of copper sulfate, 80 ppm of chloride ions, 0.001 / L of sodium polydithiopropane sulfonate, and 1 g / L of polyethylene glycol. When electroplating, 3 w.t.% of h-BN is added to the electroplating copper solution, and h-BN grows inside the metallic copper to form a composite copper pad. The electroplating current density is 20 Ma / cm 2 。

[0116] 6) Sequentially perform stripping, leveling, etching, electroless plating, and pre-cutting on the AlN ceramic substrate to form a heat sink bracket.

[0117] Among them, the formed composite copper pad is a copper-h-BN composite material, and the linear thermal expansion coefficient of the composite material is 14.2×10 -6 C -1 , and the linear thermal expansion coefficient of the formed composite copper pad is quite different from that of the gallium arsenide chip (5.7×10 -6 C -1 ), and it cannot match the thermal expansion coefficients of common chips on the market; it shows that when the range of adding nanomaterials exceeds 0.1% - 1% of the present invention, adverse effects will occur, which is likely because too large an addition amount will cause agglomeration during the material composite process, instead hindering the effect of reducing the thermal expansion coefficient.

[0118] Comparative Example 3

[0119] 1) Provide an AlN ceramic substrate with a size of 120 mm × 120 mm and a thickness of 0.38 mm.

[0120] 2) Drill holes at corresponding positions on the AlN ceramic substrate with a hole diameter of 100 μm.

[0121] 3) Perform PVD sputtering on the AlN ceramic substrate to form a titanium layer and a copper layer on its surface to form a seed layer.

[0122] 4) A photoresist layer is formed on the seed layer, and the photoresist layer is successively exposed and developed to form an opening in the photoresist layer, and a pattern of a composite metal pad is formed on the photoresist layer.

[0123] 5) Electroplating is performed at the opening to form a composite copper pad. Among them, the electroplating metal solution contains 220 g / L of sulfuric acid, 60 g / L of copper sulfate, 80 ppm of chloride ions, 0.001 / L of sodium polydithiopropane sulfonate, and 1 g / L of polyethylene glycol. When electroplating, 0.05 w.t.% of h-BN is added to the electroplating copper solution. h-BN grows inside the metallic copper to form a composite copper pad. The electroplating current density is 20 Ma / cm 2 .

[0124] 6) The AlN ceramic substrate is successively demasked, planarized, etched, electroless plated, and pre-cut to form a heat sink bracket.

[0125] Among them, the formed composite copper pad is a copper-h-B composite material, and the linear thermal expansion coefficient of the composite material is 16.9×10 -6 °C -1, The linear thermal expansion coefficient of the formed composite copper pad is quite different from that of the gallium arsenide chip (5.7×10 -6 °C -1 ). This shows that in the method provided by the present invention, it is inappropriate to add less than 0.1% of the nanomaterial. This may be because the relatively small addition amount results in h-BN with a lower internal thermal expansion coefficient being unable to reduce the thermal expansion coefficient of the overall composite material to a level equivalent to that of the chip.

[0126] Exemplarily, as Figure 2 shown, another aspect of the embodiments of the present disclosure provides a semiconductor laser heat sink bracket 100, which is prepared by using the semiconductor laser heat sink bracket preparation method S100 described above. The specific preparation process of the semiconductor laser heat sink bracket preparation method S100 has been described in detail above and will not be elaborated here. The semiconductor laser heat sink bracket 100 includes a substrate 110 and composite metal pads 120 respectively disposed on the front and back of the substrate 110. Among them, the thermal expansion coefficient of the composite metal pad is the same as or similar to that of the chip mounted on the front of the composite metal pad 120.

[0127] It should be noted that the heat sink bracket of the embodiments of the present disclosure can be applied to high-power semiconductor lasers, and can also be applied to power electronic devices, high-power microwave and radio frequency components, high-power LED lighting, etc.

[0128] The heat sink bracket of the semiconductor laser according to the embodiment of the present disclosure is prepared by using the preparation method described above. The thermal expansion coefficient of the composite metal pad is the same as or similar to that of the chip mounted on the front surface of the composite metal pad, avoiding the problem that the stress generated by thermal expansion may damage the chip and extending the device life.

[0129] Another aspect of the embodiment of the present disclosure provides a semiconductor laser, including the semiconductor laser heat sink bracket 100 described above. The specific structural features and preparation methods of the semiconductor laser heat sink bracket 100 have been described in detail above and will not be repeated here.

[0130] As Figure 3 shown, the semiconductor laser 200 according to the embodiment of the present disclosure includes the semiconductor laser heat sink bracket described above and a chip 210. The chip 210 is disposed on the composite metal pad 120 on the front surface of the substrate 110. The thermal expansion coefficient of the composite metal pad 120 in the heat sink bracket is the same as or similar to that of the chip 210, reducing the thermal stress damage of the chip and improving the reliability of the semiconductor laser.

[0131] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principles of the embodiments of the present disclosure. However, the embodiments of the present disclosure are not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the embodiments of the present disclosure, and these modifications and improvements are also regarded as the protection scope of the embodiments of the present disclosure.

Claims

1. A method for preparing a semiconductor laser heat sink bracket, characterized in that: The method comprises: providing a substrate; forming photoresist layers on the front and back sides of the substrate respectively, and patterning the photoresist layers to form openings on the photoresist layers; A composite metal pad is formed by electroplating in the opening; wherein, nanomaterials are added to the metal plating solution during electroplating, and the nanomaterials are embedded in the electroplated metal layer to adjust the thermal expansion coefficient of the formed composite metal pad, so that the thermal expansion coefficient of the composite metal pad is the same as or similar to the thermal expansion coefficient of a chip mounted on the composite metal pad.

2. The preparation method according to claim 1, characterized in that: The added nanomaterial includes at least one of carbon nanomaterial, boron nanomaterial and oxide nanomaterial; wherein, The content of the carbon nanomaterial is 0.1% to 1%, the content of the boron nanomaterial is 0.1% to 1%, and the content of the oxide nanomaterial is 0.1% to 2%.

3. The preparation method according to claim 2, characterized in that: The carbon nanomaterial includes at least one of graphite, graphene, graphene nanotubes, graphyne, multi-walled carbon nanotubes, C60, activated carbon, carbon fiber, carbon black, glassy carbon, porous carbon materials and carbon nanospheres.

4. The preparation method according to claim 2, characterized in that: The boron nanomaterial includes at least one of borophene, boron nanowires and boron nitride.

5. The preparation method according to claim 3, characterized in that: The oxide nanomaterial includes at least one of Al2O3, CaTiO3, TiO2 and ZrO2.

6. The preparation method according to claim 1, characterized in that: The metal plating solution comprises 60g / L to 220g / L sulfuric acid, 60g / L to 200g / L copper sulfate, 60ppm to 90ppm chloride ions, 0.001g / L to 0.005g / L sodium polydisulfide dipropane sulfonate, and 0.5g / L to 2g / L polyethylene glycol.

7. The preparation method according to any one of claims 1 to 6, characterized in that: Before forming photoresist layers on the front and back sides of the substrate respectively, the method comprises: forming seed layers on the front and back sides of the substrate respectively; The photoresist layer is formed on the seed layer.

8. The preparation method according to any one of claims 1 to 6, characterized in that: After forming the composite metal pad, the method further includes: The substrate is sequentially subjected to film stripping, leveling, etching, chemical plating, and pre-cutting to form the heat sink bracket.

9. A semiconductor laser heat sink bracket, characterized in that: The method is prepared by any one of claims 1 to 8.

10. A semiconductor laser, characterized in that: It comprises the semiconductor laser heat sink bracket as claimed in claim 9.

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