A composite heat sink, a preparation method thereof, and a semiconductor laser

Abstract

This application relates to the field of semiconductor manufacturing technology, and provides a composite heat sink, a preparation method thereof, and a semiconductor laser. The preparation method includes attaching super-aligned single-walled carbon nanotubes to the first surface of the first metal layer; attaching a protective layer to the second surface; electroplating a second metal layer on the surface of the super-aligned single-walled carbon nanotubes to form a composite structure; repeating the preparation of the composite structure N times; removing the protective layer and the first metal layer to obtain a first heat sink structure; and bonding with a second heat sink structure to obtain a composite heat sink. This preparation method can utilize the high axial heat conduction characteristic of the super-aligned single-walled carbon nanotubes, and use the second metal to improve the bonding effect between the first heat sink structure and the second heat sink structure. When applied as a heat sink to a semiconductor laser, it can increase the heat conduction rate in the plane direction in the semiconductor laser, reduce the interfacial thermal resistance, improve the heat dissipation ability, and ensure the reliability and service life of the semiconductor laser.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a composite heat sink and a manufacturing method thereof, and a semiconductor laser. Background Art

[0002] Semiconductor lasers have been widely used in many fields due to their advantages of small size, light weight, low energy consumption, easy modulation and mass production. The heat dissipation problem of semiconductor lasers has become a core technical challenge that needs to be solved in this field. The heat dissipation capacity of the laser depends largely on its heat sink structure. Usually, the heat sink uses a combination of metal and ceramic materials with excellent thermal conductivity to promote the downward diffusion of heat from the active area. Copper has a high thermal conductivity (398W•m -1 •K -1 ), is often used as a heat sink material in semiconductor laser packaging. However, the thermal expansion coefficient of copper is nearly 1.58 times different from that of the chip material, which easily generates thermal stress and causes the contact interface to be subjected to large thermal-mechanical stress.

[0003] To alleviate this problem, a transition heat sink with high thermal conductivity and expansion coefficient closer to the chip is usually introduced between the chip and the copper-based conventional heat sink. Carbon nanotubes have high thermal conductivity (3000~6000W•m -1 •K -1 ) is a very promising transition heat sink material, but the contact area between the carbon nanotubes in the carbon nanotube network film is small, and there is phonon scattering at the interface, which leads to low efficiency of heat transfer between the tubes, which is not conducive to the rapid transmission of heat. In addition, when the carbon nanotube film is combined with the basic heat sink, insufficient chemical bonding at the interface will further increase the thermal resistance and reduce the overall heat dissipation performance, making it impossible to effectively exert the heat dissipation advantages of the transition heat sink.

[0004] Therefore, there is an urgent need for a heat sink structure that can achieve good bonding between the carbon nanotube film and the basic heat sink material, reduce the interface thermal resistance, and thus improve the overall heat dissipation performance of the semiconductor laser. Summary of the invention

[0005] The composite heat sink and its preparation method, as well as the semiconductor laser proposed in this application, can solve the technical problem of bonding the carbon nanotube film to the basic heat sink material, reduce the interface thermal resistance, and improve the heat dissipation effect of the laser.

[0006] The preparation method of the composite heat sink provided by the first aspect of the present application includes: attaching super-aligned single-walled carbon nanotubes to the first surface of the first metal layer; attaching a protective layer to the second surface of the first metal layer; the first surface and the second surface are two opposite surfaces of the first metal layer; electroplating a second metal layer on the surface of the super-aligned single-walled carbon nanotubes to form a composite structure of the super-aligned single-walled carbon nanotubes and the second metal layer; wherein, the electroplating conditions include: the super-aligned single-walled carbon nanotubes, the first metal layer and the protective layer serve as the cathode, the second metal serves as the anode, and the cathode and the anode are placed in the electrolyte; repeating the preparation of the composite structure N times; removing the protective layer and the first metal layer to obtain the first heat sink structure; bonding the first heat sink structure with the second heat sink structure to obtain the composite heat sink; wherein, the second heat sink structure is a heat sink structure containing the second metal.

[0007] In some feasible implementation manners, removing the protective layer and the first metal layer includes: peeling off the protective layer; placing the whole of a plurality of composite structures and the first metal layer in an acidic solution to corrode the first metal layer; wherein, the pH of the acidic solution is less than 1.

[0008] In some feasible implementation manners, the first metal layer is one of titanium, aluminum or zinc; the second metal is copper; the electrolyte is a mixed solution of CuSO4•5H2O, H2SO4, chloride ions and a leveling agent.

[0009] In some feasible implementation manners, the concentration of CuSO4•5H2O is 170 - 220 g / L; the concentration of H2SO4 is 45 - 75 g / L; the concentration of chloride ions is 40 - 100 ppm.

[0010] In some feasible implementation manners, the leveling agent includes sodium polydithiopropane sulfonate or glucose; the concentration of sodium polydithiopropane sulfonate is 10 - 50 mg / L, and the concentration of glucose is 2 - 8 g / L.

[0011] In some feasible implementation manners, N is greater than or equal to 5 and less than or equal to 20.

[0012] In some feasible implementation manners, after S5 and before S6, the preparation method of the composite heat sink further includes: S51: cleaning the first heat sink structure successively with acetone, alcohol and deionized water.

[0013] In some feasible implementation manners, the electroplating conditions further include: the current is 0.025 - 0.05 A / cm 2 and the electroplating time is 6 - 10 min.

[0014] The preparation method of the composite heat sink provided in the first aspect of the present application embeds a second metal layer in the super-aligned single-walled carbon nanotubes as the first heat sink structure. After bonding with the second heat sink structure, the obtained composite heat sink can utilize the high axial heat conduction characteristics of the super-aligned single-walled carbon nanotubes, and by using the second metal, improve the bonding effect between the first heat sink structure and the second heat sink structure. Applying this composite heat sink to a semiconductor laser can increase the heat conduction rate in the plane direction in the semiconductor laser, reduce the interfacial thermal resistance, improve the heat dissipation ability, and ensure the reliability and service life of the semiconductor laser.

[0015] The composite heat sink provided in the second aspect of the present application includes: a first heat sink structure and a second heat sink structure; the first heat sink structure is bonded to the second heat sink structure.

[0016] The composite heat sink provided in the second aspect of the present application is prepared by the preparation method of the composite heat sink provided in the first aspect, and its beneficial technical effects can be referred to the first aspect, which will not be elaborated here.

[0017] The semiconductor laser provided in the third aspect of the present application includes a laser chip and the composite heat sink provided in the second aspect; the laser chip is welded on the first heat sink structure of the composite heat sink. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0019] Figure 1 is a schematic flow chart of a preparation method of a composite heat sink provided by an embodiment of the present application;

[0020] Figure 2 is a schematic process flow chart of the preparation of the first composite heat sink provided by an embodiment of the present application;

[0021] Figure 3 is a schematic process flow chart of the preparation of the second composite heat sink provided by an embodiment of the present application;

[0022] Figure 4 is a schematic structural diagram of a semiconductor laser provided by an embodiment of the present application.

[0023] Illustration Marks:

[0024] 100 - Composite heat sink; 10 - Ultra - aligned single - walled carbon nanotubes; 20 - First metal layer; 21 - First surface; 22 - Second surface; 30 - Protective layer; 40 - Second metal layer; 50 - Composite structure; 60 - First heat sink structure; 61 - Third surface; 62 - Fourth surface; 70 - Second heat sink structure; 80 - Bonding layer; 200 - Laser chip; 300 - Welding layer. Detailed implementation manners

[0025] The following will clearly describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all embodiments. Based on the embodiments of the present application, other embodiments obtained by those of ordinary skill in the art without creative efforts all fall within the protection scope of the present application.

[0026] Hereinafter, terms such as "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0027] In addition, in the present application, orientation terms such as "upper", "lower", "inner", "outer", etc. are defined relative to the orientation of the components shown in the accompanying drawings. It should be understood that these directional terms are relative concepts, and they are used for relative description and clarification, and they can change accordingly with the change of the orientation of the components placed in the accompanying drawings.

[0028] As an intermediate heat sink material, the carbon nanotube network film has anisotropy during the heat transfer process, and the axial transfer efficiency is the highest. However, the contact area between carbon nanotubes in the network film is small, and there is phonon scattering at the interface, resulting in low heat transfer efficiency between tubes, which is not conducive to rapid heat transfer. In addition, when the carbon nanotube film is combined with the base heat sink, insufficient interfacial chemical bonding will further increase the thermal resistance and reduce the overall heat dissipation performance, making it impossible to effectively exert the heat dissipation advantage of the intermediate heat sink.

[0029] Therefore, there is an urgent need to propose a new method that can not only ensure the high thermal conductivity of carbon nanotubes is exerted, but also enable the carbon nanotube film to achieve good bonding with the base heat sink material, reduce the interfacial thermal resistance, and thus improve the overall heat dissipation performance of the semiconductor laser.

[0030] Figure 1 is a schematic flow chart of a method for preparing a composite heat sink provided by an embodiment of the present application; Figure 2 is a schematic process flow chart of the preparation of the first composite heat sink provided by an embodiment of the present application.

[0031] Combined with Figure 1 and Figure 2 As shown, the preparation method of the composite heat sink provided by the embodiments of the present application can be realized by the following steps S1 to S6.

[0032] Step S1: Attach the super-aligned single-walled carbon nanotubes 10 to the first surface 21 of the first metal layer 20.

[0033] Among them, the super-aligned single-walled carbon nanotubes 10 are a type of carbon nanotubes. "Super-aligned" means that the carbon nanotubes are highly ordered at the macroscopic or microscopic scale, forming an array or film with a consistent direction; "single-walled" is a seamless tubular nanomaterial formed by curling a single-layer graphene sheet (i.e., a two-dimensional honeycomb lattice composed of a single layer of carbon atoms).

[0034] In step S1, the first metal is in sheet form, and the super-aligned single-walled carbon nanotubes 10 are in film structure. During the attachment process, the film of the super-aligned single-walled carbon nanotubes 10 can be placed on the first surface 21 of the first metal layer 20, and alcohol is dropped on the super-aligned single-walled carbon nanotubes 10 to wet the surface. The alcohol can wet the super-aligned single-walled carbon nanotubes 10 and the first surface 21 of the first metal layer 20, so that the super-aligned single-walled carbon nanotubes 10 are attached to the first metal layer 20.

[0035] The purpose of dropping alcohol is that alcohol will not corrode the super-aligned single-walled carbon nanotubes 10 and the first metal layer 20. At the same time, the low surface tension property of alcohol can enhance the physical anchoring of the super-aligned single-walled carbon nanotubes 10 on the first surface 21 of the first metal layer 20. In addition, the rapid volatility of alcohol can maintain the uniformity of the carbon nanotube film and has a certain cleaning effect, providing a clean coating surface for electroplating the second metal layer 40 later.

[0036] The first metal layer 20 mainly provides a coating basis for electroplating the second metal layer 40 on the surface of the super-aligned single-walled carbon nanotubes 10 in the embodiments of the present application. After the electroplating of the second metal layer 40 is completed later, the first metal layer 20 can be peeled off.

[0037] After step S1 is executed, the structure in (a) as shown in Figure 2 can be obtained.

[0038] In some feasible implementation manners, the super-aligned single-walled carbon nanotubes 10 mentioned in the embodiments of the present application can be prepared or can adopt a finished product structure. If the super-aligned single-walled carbon nanotubes 10 are prepared, before step S1, the preparation method should also include step S01.

[0039] Step S01: Prepare the super-aligned single-walled carbon nanotubes 10 by chemical vapor deposition technology.

[0040] Step S2: Attach a protective layer 30 to the second surface 22 of the first metal layer 20.

[0041] Among them, the first surface 21 and the second surface 22 are two opposite surfaces of the first metal layer 20. That is to say, the protective layer 30 is attached to the side of the first metal layer 20 away from the super-aligned single-walled carbon nanotubes 10, thereby protecting the second surface 22 and avoiding the difficulty of separating the first metal layer 20 from the super-aligned single-walled carbon nanotubes 10 due to coating on the second surface 22.

[0042] The material of the protective layer 30 needs to satisfy not being corroded by the electrolyte.

[0043] In some feasible implementation manners, the protective layer 30 can be one of a polyimide tape, a polyvinyl chloride (PVC) film, or an epoxy resin (such as SU-8).

[0044] After step S2 is completed, the structure shown in (b) in Figure 2 can be obtained.

[0045] Take the overall structure of the prepared super-aligned single-walled carbon nanotubes 10, the first metal layer 20, and the protective layer 30 as the cathode, and the second metal as the anode, and place them in the electrolyte. The anode and the cathode can be respectively connected to wires, and a current can be conducted between the wires. Among them, the anode can be in a rod-like structure to meet the power-on effect.

[0046] Placing it in the electrolyte can obtain the structure shown in (c) in Figure 2 . During the process of current conduction, an oxidation reaction occurs on the anode surface of the second metal, and a reduction reaction occurs on the cathode surface.

[0047] Step S3: Electroplate a second metal layer 40 on the surface of the super-aligned single-walled carbon nanotubes 10 to form a composite structure 50 of the super-aligned single-walled carbon nanotubes 10 and the second metal layer 40.

[0048] In step S3, in the case of power-on, as the electroplating time increases continuously, a second metal layer 40 can be formed on the surface of the cathode. Among them, the preparation thickness of the second metal layer 40 can be controlled by controlling the electroplating current magnitude and adjusting the electroplating time. Specifically, the formed second metal layer 40 is in a thin film structure. Since the super-aligned single-walled carbon nanotubes 10 are in a thin film structure, in the formed composite structure 50, the second metal layer 40 is not only formed on the surface of the super-aligned single-walled carbon nanotubes 10, but also formed between the gaps of the thin film structure of the super-aligned single-walled carbon nanotubes 10, thereby forming a composite structure 50 of the super-aligned single-walled carbon nanotubes 10 and the second metal layer 40 in an integral structure. In this way, the connection strength between the super-aligned single-walled carbon nanotubes 10 and the second metal layer 40 is also improved.

[0049] In some feasible implementation manners, the first metal can be one of titanium, aluminum or zinc. Titanium, aluminum or zinc has good electrical conductivity. Moreover, the usage amount of the first metal layer 20 in the embodiments of the present application is not large, and its cost does not need to be overly considered. A suitable first metal layer 20 can be selected according to the actual preparation environment.

[0050] The second metal can be copper, and the electrolytic solution can be a mixed solution containing copper ions. The obtained second metal layer 40 can be a thin film layer of metallic copper. Specifically, the electrolytic solution can be a mixed solution of copper sulfate pentahydrate (CuSO4•5H2O), sulfuric acid (H2SO4), chloride ions (Cl - ) and a leveling agent.

[0051] Among them, the concentration of CuSO4•5H2O can be 170 - 220 g / L. For example, the concentration of CuSO4•5H2O can be one of 170 g / L, 180 g / L, 190 g / L, 200 g / L, 210 g / L or 220 g / L. Of course, the concentration of CuSO4•5H2O can also be other concentrations within 170 - 220 g / L.

[0052] The concentration of H2SO4 is 45 - 75 g / L. For example, the concentration of H2SO4 can be 45 g / L, 55 g / L, 65 g / L or 75 g / L. Of course, the concentration of H2SO4 can also be other concentrations within 45 - 75 g / L.

[0053] The chloride ions can be provided by one or more of hydrochloric acid (HCl), sodium chloride (NaCl), potassium chloride (KCl) and copper chloride (CuCl2). Among them, the concentration of the chloride ions (Cl - ) can be 40 - 100 ppm. For example, the concentration of Cl - can be one of 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm or 100 ppm. Of course, the concentration of Cl - can also be other concentrations within 40 - 100 ppm.

[0054] As an additive, the leveling agent can effectively ensure the flatness of the surface of the electroplated second metal layer 40, making the surface of the second metal layer 40 relatively smooth and flat.

[0055] In some feasible implementation manners, the leveling agent can be sodium polydithiopropane sulfonate or glucose.

[0056] Exemplarily, when the leveling agent is sodium polydithiopropane sulfonate, the concentration of sodium polydithiopropane sulfonate can be 10 - 50 mg / L. Exemplarily, the concentration of sodium polydithiopropane sulfonate can be one of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L or 50 mg / L. Of course, the concentration of sodium polydithiopropane sulfonate can also be the remaining concentrations within 10 - 50 mg / L.

[0057] Exemplarily, when the leveling agent is glucose, the concentration of glucose can be 2 - 8 g / L. Exemplarily, the concentration of glucose can be 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L or 8 g / L. Of course, the concentration of glucose can also be the remaining concentrations within 2 - 8 g / L.

[0058] In a specific implementation, the concentration of CuSO4·5H2O is 200 g / L; the concentration of H2SO4 is 50 g / L; the chloride ion concentration is 80 ppm; the concentration of sodium polydithiopropane sulfonate is 30 mg / L or the concentration of glucose is 5 g / L. On the premise of ensuring the conductivity of the electrolyte, avoid increasing the solution viscosity due to too high concentration. In this way, the migration speed of ions can be effectively guaranteed.

[0059] In some feasible implementation manners, the electroplating conditions include that the current is: 0.025 - 0.05 A / cm 2 , and the electroplating time is 6 - 10 min. Specifically, in the actual preparation process, the thickness of the coating (the second metal layer 40) can be controlled by adjusting the current and the electroplating time. Exemplarily, the greater the current, the shorter the electroplating time, and the relatively thinner the second metal layer 40. The smaller the current, the longer the electroplating time, and the relatively thicker the second metal layer 40.

[0060] Exemplarily, the current can be 0.025 A / cm 2 , 0.035 A / cm 2 , 0.045 A / cm 2 or 0.05 A / cm 2 of one kind. Exemplarily, the electroplating time can be one of 6 min, 7 min, 8 min, 9 min or 10 min.

[0061] In a specific implementation, the current is 0.03 A / cm 2 , and the electroplating time is 8 min. In this way, by selecting appropriate current and electroplating time, while ensuring the coating quality, the electroplating effect is improved.

[0062] After step S3 is completed, the structure shown in (d) in Figure 2 can be obtained.

[0063] Of course, in other feasible implementation manners, the second metal can also be other metals such as silver with high thermal conductivity and low coefficient of thermal expansion. Correspondingly, the electrolyte solution can be adaptively adjusted according to the type of the actual second metal. For example, if the second metal is silver, the electrolyte is a corresponding mixed solution containing silver elements.

[0064] Step S4: Repeat the preparation of the composite structure 50 for N times.

[0065] After step S3 is completed, disconnect the current in the connected electrolyte, take out the cathode from the electrolyte, attach another layer of super-aligned single-walled carbon nanotubes 10 on the second metal layer 40, and then repeat the preparation process of the second metal layer 40. That is to say, after one composite structure 50 is prepared, multiple composite structures 50 are prepared repeatedly.

[0066] In some feasible implementation manners, N is a positive integer. N is greater than or equal to 5 and less than or equal to 20. In this way, N + 1 composite structures 50 can be obtained, which can give full play to the heat dissipation performance of the super-aligned single-walled carbon nanotubes 10 and can also ensure the interface bonding requirements between the heat sinks through the second metal layer 40.

[0067] For example, N can be one of 5, 10, 15, or 20. Of course, N can also be other values in 5 - 20. The value of N can be adaptively adjusted according to the heat dissipation requirements of the laser.

[0068] It should be noted that during the preparation process of each composite structure 50, the magnitude of the current and the electroplating time can be the same or different. Among them, the flat surface of the second metal layer 40 can be achieved by the cooperation of the leveling agent and the electroplating current.

[0069] Figure 3 It is a schematic diagram of the preparation process flow of the second composite heat sink provided by the embodiment of the present application.

[0070] See Figure 3 As shown, after step S4 is completed, the structure shown in (a) in Figure 3 can be obtained.

[0071] Step S5: Remove the protective layer 30 and the first metal layer 20 to obtain the first heat sink structure 60.

[0072] After N + 1 composite structures 50 are prepared, disconnect the current between the anode and the cathode, and take out the cathode from the electrolyte.

[0073] After taking it out, the following step S51 and step S52 can be executed.

[0074] Step S51: Peel off the protective layer 30.

[0075] The protective layer 30 can be peeled off from the surface of the first metal layer 20 using a scalpel or forceps.

[0076] Step S52: Place the entirety of the multiple composite structures 50 and the first metal layer 20 in an acidic solution to corrode the first metal layer 20.

[0077] After step S52 is completed, a first heat sink structure 60 including multiple composite structures 50 can be obtained. Among them, the acidic solution can corrode the first metal layer 20, but will not corrode the multiple composite structures 50.

[0078] In some feasible implementation manners, the acidic solution can include hydrochloric acid or sulfuric acid. Specifically, the pH of the acidic solution is less than 1, such that the acidic solution has strong corrosiveness and can corrode the first metal layer 20 relatively quickly, achieving rapid peeling of the first heat sink structure 60 and improving the preparation efficiency.

[0079] After step S5 is completed, the preparation method of the composite heat sink can further include step S53 and step S54.

[0080] Step S53: Clean the first heat sink structure 60 using acetone, alcohol, and deionized water.

[0081] Among them, acetone and alcohol can be of analytical purity. The cleaning operation can be carried out at room temperature. The number of cleaning times can be determined according to the cleanliness of the first heat sink structure 60.

[0082] Step S54: Dry the first heat sink structure 60.

[0083] In this way, after drying, Figure 3 the structure shown in (b) in

[0084] Step S6: Bond the first heat sink structure 60 with the second heat sink structure 70 to obtain the composite heat sink 100.

[0085] Among them, the first heat sink structure 60 can be used as an intermediate heat sink, and the second heat sink structure 70 can be used as a basic heat sink. The second heat sink structure 70 is a heat sink structure containing a second metal, and the thickness of the first heat sink structure 60 is less than that of the second heat sink structure 70. In this way, the super-aligned single-walled carbon nanotubes 10 in the first heat sink structure 60 can exert their relatively high axial thermal conductivity, quickly diffusing and transferring heat to the surrounding area, and avoiding heat concentration caused by untimely heat transfer to the second heat sink structure 70. Subsequently, the first heat sink structure 60 can transfer heat to the second heat sink structure 70 with a larger area to improve the heat dissipation effect. Moreover, the metal elements contained in the first heat sink structure 60 and the second heat sink structure 70 are the same, enabling the first heat sink structure 60 to be well bonded to the second heat sink structure 70, which is conducive to heat transfer between the first heat sink structure 60 and the second heat sink structure 70 and effectively improves the heat dissipation effect.

[0086] After step S6 is completed, the structure shown in Figure 3 (c) can be obtained.

[0087] In some feasible implementation manners, the second metal layer 40 can be a copper metal layer, and the corresponding second heat sink structure 70 can be a copper heat sink.

[0088] In some feasible implementation manners, the first heat sink structure 60 and the second heat sink structure 70 can adopt thermocompression bonding or low-temperature bonding. Adopting thermocompression bonding can reduce the yield strength of the first heat sink structure 60 and the second heat sink structure 70, promoting the mutual diffusion and combination of interface atoms, which is beneficial to ensuring the bonding effect. Adopting low-temperature bonding can be carried out in a low-temperature or even room-temperature environment, avoiding damage to heat-sensitive materials caused by high temperatures. During the actual bonding process, the bonding method can be selected according to the characteristics of the second metal.

[0089] Specifically, during the bonding process, a bonding layer 80 will be formed between the first heat sink structure 60 and the second heat sink structure 70.

[0090] It should be emphasized that the first heat sink structure 60 includes two opposite surfaces, namely a third surface 61 that fits against the first surface 21 of the first metal layer 20, and a fourth surface 62 of the second metal layer 40 formed in the electrolyte. Among them, the third surface 61 is a composite surface composed of the super-aligned single-walled carbon nanotubes 10 and the second metal layer 40, while the fourth surface 62 is entirely the surface of the second metal layer 40. And due to the presence of a leveling agent in the electrolyte, the fourth surface 62 is a relatively flat surface. Therefore, when bonding the first heat sink structure 60 and the second heat sink structure 70, the fourth surface 62 is preferably used as the bonding surface. On the one hand, it improves the bonding efficiency between the first heat sink structure 60 and the second heat sink structure 70. On the other hand, the subsequent chip is disposed on the third surface 61, thus facilitating the heat conduction along the axial direction of the super-aligned single-walled carbon nanotubes 10.

[0091] Of course, in another feasible implementation, the second heat sink structure 70 can also be bonded to the third surface 61 of the first heat sink structure 60.

[0092] The preparation method of the composite heat sink provided by the embodiments of the present application embeds the second metal layer 40 in the super-aligned single-walled carbon nanotubes 10 as the first heat sink structure 60. After bonding with the second heat sink structure 70, the obtained composite heat sink 100 can exert the high axial heat conduction characteristics of the super-aligned single-walled carbon nanotubes 10. And by using the second metal layer 40, it can improve the bonding effect between the first heat sink structure 60 and the second heat sink structure 70. When applied as a heat sink to a semiconductor laser, it can increase the heat conduction rate along the planar direction in the semiconductor laser, reduce the interfacial thermal resistance, improve the heat dissipation capacity, and ensure the reliability and service life of the semiconductor laser. Moreover, the preparation method provided by the embodiments of the present application is relatively simple, does not require damage to the super-aligned single-walled carbon nanotubes 10, and can directly form the first heat sink structure 60 integrated with the second metal layer 40 in the solution, effectively improving the overall strength of the first heat sink structure 60, and further ensuring the overall performance of the composite heat sink 100.

[0093] Corresponding to the embodiments of the preparation method of the foregoing composite heat sink, the present application also provides an embodiment of the composite heat sink 100. The composite heat sink 100 is prepared by the preparation method of the composite heat sink provided by the above embodiments.

[0094] Continue to refer to Figure 3 As shown in (c) in the figure, the composite heat sink 100 includes a first heat sink structure 60, a second heat sink structure 70, and a bonding layer 80.

[0095] The first heat sink structure 60 is bonded to the second heat sink structure 70 through a bonding layer 80. Among them, the first heat sink structure 60 can be prepared by steps S1 to S5 in the preparation method of the above composite heat sink. The bonding operation between the first heat sink structure 60 and the second heat sink structure 70 can be realized by step S6 in the preparation method of the above composite heat sink.

[0096] Corresponding to the foregoing embodiments of the composite heat sink 100, the present application also provides an embodiment of a semiconductor laser.

[0097] Figure 4 It is a schematic structural diagram of a semiconductor laser provided by an embodiment of the present application.

[0098] See Figure 4 As shown, the semiconductor laser includes a laser chip 200 and the composite heat sink 100 mentioned in the above embodiment welded on the laser chip 200.

[0099] Specifically, the laser chip 200 is welded to the first heat sink structure 60 in the composite heat sink 100 through a welding layer 300. During the operation of the semiconductor laser, the heat generated by the laser chip 200 can be quickly conducted by using the high axial thermal conductivity of the super-aligned single-walled carbon nanotubes 10, realizing the rapid and efficient transfer and diffusion of heat.

[0100] In some feasible implementation manners, the laser chip 200 can be an edge-emitting laser or a vertical-cavity surface-emitting laser. That is to say, the composite heat sink 100 structure in the embodiment of the present application can dissipate heat for an edge-emitting laser or a vertical-cavity surface-emitting laser, and has wide usability.

[0101] It should be noted that those skilled in the art will easily think of other implementation schemes of the present application after considering the specification and practicing the application disclosed herein. The present application aims to cover any variations, uses or adaptations of the present application, and these variations, uses or adaptations follow the general principles of the present application and include the common general knowledge or conventional technical means in the technical field not disclosed in the present application.

[0102] It should be understood that the present application is not limited to the exact structure already described and shown in the drawings, and various modifications and changes can be made without departing from its scope. The true scope is indicated by the present application.

Claims

1. A preparation method of a composite heat sink, characterized in that, Including: Attach the super-aligned single-walled carbon nanotubes to the first surface of the first metal layer; Attach a protective layer to the second surface of the first metal layer; The first surface and the second surface are two opposite surfaces of the first metal layer; Electroplate a second metal layer on the surface of the super-aligned single-walled carbon nanotubes to form a composite structure of the super-aligned single-walled carbon nanotubes and the second metal layer; wherein, the electroplating conditions include: using the super-aligned single-walled carbon nanotubes, the first metal layer and the protective layer as the cathode, and the second metal as the anode, and placing the cathode and the anode in an electrolyte; Repeat the preparation of the composite structure N times; N is a positive integer; Remove the protective layer and the first metal layer to obtain a first heat sink structure; Bond the first heat sink structure to a second heat sink structure to obtain a composite heat sink; wherein, the second heat sink structure is a heat sink structure containing the second metal; The electroplating conditions further include: the current is 0.025 - 0.05 A / cm 2 , and the electroplating time is 6 - 10 min.

2. The method for preparing the composite heat sink according to claim 1, wherein The removing of the protective layer and the first metal layer includes: Peel off the protective layer; Place the whole of multiple composite structures and the first metal layer in an acidic solution to corrode the first metal layer; wherein, the pH of the acidic solution is less than 1.

3. The method for preparing the composite heat sink according to claim 1, wherein The first metal layer is one of titanium, aluminum or zinc; The second metal is copper; The electrolyte is a mixed solution of CuSO4•5H2O, H2SO4, chloride ions and a leveling agent.

4. The method for preparing the composite heat sink according to claim 3, wherein The concentration of CuSO4•5H2O is 170 - 220 g / L; The concentration of H2SO4 is 45 - 75 g / L; The concentration of chloride ions is 40 - 100 ppm.

5. The method for preparing the composite heat sink according to claim 3, wherein The leveling agent includes sodium polydithiopropane sulfonate or glucose; The concentration of sodium polydithiopropane sulfonate is 10 - 50 mg / L, and the concentration of glucose is 2 - 8 g / L.

6. The method for preparing the composite heat sink according to claim 1, wherein N is greater than or equal to 5 and less than or equal to 20.

7. The method for preparing the composite heat sink according to claim 1, wherein The method for preparing the composite heat sink further includes: Clean the first heat sink structure successively with acetone, alcohol and deionized water.

8. A composite heat sink, characterized in that, Using the method for preparing the composite heat sink according to any one of claims 1 - 7, the composite heat sink includes: A first heat sink structure and a second heat sink structure; The first heat sink structure is bonded to the second heat sink structure.

9. A semiconductor laser, characterized in that, Including a laser chip and the composite heat sink according to claim 8; The laser chip is welded to the first heat sink structure of the composite heat sink.

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