Composite heat sink, preparation method thereof and semiconductor laser

Abstract

The invention relates to the technical field of semiconductor preparation, and provides a composite heat sink and a preparation method thereof, and a semiconductor laser. The preparation method comprises the following steps: attaching the 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 nanotube to form a composite structure; repeating N times to prepare a composite structure; removing the protective layer and the first metal layer to obtain a first heat sink structure; and bonding with the second heat sink structure to obtain the composite heat sink. According to the preparation method, the axial high heat conduction characteristic of the super-aligned single-walled carbon nanotube can be exerted, the bonding effect between the first heat sink structure and the second heat sink structure is improved by utilizing the second metal, the super-aligned single-walled carbon nanotube is applied to the semiconductor laser as a heat sink, the conduction rate of heat in the semiconductor laser in the plane direction can be improved, and the laser performance is improved. The interface thermal resistance is reduced, the heat dissipation capability is improved, and the reliability and service life of the semiconductor laser are ensured.

Description

Technical Field

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

[0002] Due to its many advantages such as small volume, light weight, low energy consumption, easy modulation, and batch production, semiconductor lasers have been widely used in many fields. The heat dissipation problem of semiconductor lasers has become a core technical challenge that needs to be solved urgently in this field. The heat dissipation ability of a laser largely depends on its heat sink structure. Generally, the heat sink combines metals and ceramic materials with excellent thermal conductivity to promote the downward diffusion of heat from the active region. Copper, due to its high thermal conductivity (398 W•m -1 •K -1 ), is often used as a heat sink material in semiconductor laser packaging. However, the thermal expansion coefficient of copper differs from that of the chip material by nearly 1.58 times, which easily generates thermal stress, causing the contact interface to bear a large thermal-mechanical stress.

[0003] To alleviate this problem, a transition heat sink with high thermal conductivity and a thermal expansion coefficient closer to that of the chip is usually introduced between the chip and the copper-based conventional heat sink. Carbon nanotubes are potential transition heat sink materials due to their high thermal conductivity (3000 - 6000 W•m -1 •K -1 ). However, the contact area between carbon nanotubes in the network film of carbon nanotubes 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 utilize the heat dissipation advantage 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 base heat sink material, reduce the interfacial thermal resistance, and thus improve the overall heat dissipation performance of the semiconductor laser. Summary of the Invention

[0005] The composite heat sink, its preparation method, and the semiconductor laser provided by the present application can solve the technical problem of bonding between the carbon nanotube film and the base heat sink material, reduce the interfacial 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: 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; 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 the 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 CuSO 4 •5H 2 O, H 2 SO 4 , chloride ions and a leveling agent.

[0009] In some feasible implementation manners, the concentration of CuSO 4 •5H 2 O is 170 - 220 g / L; the concentration of H 2 SO 4 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. The composite heat sink obtained after bonding with the second heat sink structure can exert the high axial heat conduction characteristics 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. Applying this composite heat sink to a semiconductor laser can improve 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 the beneficial technical effects thereof can be seen in 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 be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is a schematic flowchart of a preparation method of a composite heat sink provided by an embodiment of the present application; Figure 2 It is a schematic process flow diagram of the preparation of the first composite heat sink provided by an embodiment of the present application; Figure 3 It is a schematic process flow diagram of the preparation of the second composite heat sink provided by an embodiment of the present application; Figure 4 It is a schematic structural diagram of a semiconductor laser provided by an embodiment of the present application.

[0020] Illustration Marks: 100 - Composite heat sink; 10 - Super-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

[0021] 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 the 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.

[0022] 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 of" is two or more.

[0023] 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.

[0024] 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 and being unfavorable for 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.

[0025] 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.

[0026] Figure 1 is a schematic flowchart of a method for preparing a composite heat sink provided by an embodiment of the present application; Figure 2 is a schematic process flow diagram of the preparation of the first composite heat sink provided by an embodiment of the present application.

[0027] Combined with Figure 1 and Figure 2 As shown, the method for preparing the composite heat sink provided by the embodiment of the present application can be implemented by the following steps S1 to S6.

[0028] Step S1: Attach the super-aligned single-walled carbon nanotubes 10 to the first surface 21 of the first metal layer 20.

[0029] 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).

[0030] In step S1, the first metal is in sheet form, and the super-aligned single-walled carbon nanotubes 10 are in a 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, causing the super-aligned single-walled carbon nanotubes 10 to attach to the first metal layer 20.

[0031] 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.

[0032] 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.

[0033] After step S1 is completed, the structure shown in (a) can be obtained as Figure 2 shown.

[0034] 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.

[0035] Step S01: Prepare the super-aligned single-walled carbon nanotubes 10 using chemical vapor deposition technology.

[0036] Step S2: Attach the protective layer 30 to the second surface 22 of the first metal layer 20.

[0037] 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, a protective layer 30 is attached to the side of the first metal layer 20 facing away from the super-aligned single-walled carbon nanotubes 10, so as to protect the second surface 22 and avoid 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.

[0038] The material of the protective layer 30 needs to meet the requirement of not being corroded by the electrolyte.

[0039] 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).

[0040] After step S2 is completed, the structure shown in Figure 2 (b) can be obtained.

[0041] The overall structure of the prepared super-aligned single-walled carbon nanotubes 10, the first metal layer 20, and the protective layer 30 is used as the cathode, and the second metal is used as the anode and placed 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 a rod-shaped structure to meet the current conduction effect.

[0042] Placing it in the electrolyte can obtain the structure shown in Figure 2 (c). 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.

[0043] 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.

[0044] In step S3, in the case of energization, as the electroplating time increases continuously, a second metal layer 40 can be formed on the surface of the cathode. Specifically, the thickness of the prepared 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 a thin film structure. Since the super-aligned single-walled carbon nanotubes 10 are 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 with an integrated 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.

[0045] In some feasible implementation manners, the first metal may be one of titanium, aluminum or zinc. Titanium, aluminum or zinc has good electrical conductivity. Among them, the usage amount of the first metal layer 20 in the embodiments of the present application is not large, and there is no need to overly consider its cost, and the suitable first metal layer 20 can be selected according to the actual preparation environment.

[0046] The second metal may be copper, and the electrolyte may be a mixed solution containing copper ions. The obtained second metal layer 40 may be a thin film layer of metallic copper. Specifically, the electrolyte may be a mixed solution of copper sulfate pentahydrate (CuSO 4 •5H 2 O), sulfuric acid (H 2 SO 4 ), chloride ions (Cl - ), and a leveling agent.

[0047] Among them, the concentration of CuSO 4 •5H 2 O may be 170-220 g / L. By way of example, the concentration of CuSO 4 •5H 2 O may 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 CuSO 4 •5H 2 O may also be other concentrations within 170-220 g / L.

[0048] The concentration of H 2 SO 4 is 45-75 g / L. By way of example, the concentration of H 2 SO 4 may be 45 g / L, 55 g / L, 65 g / L or 75 g / L. Of course, the concentration of H 2 SO 4 may also be other concentrations within 45-75 g / L.

[0049] The chloride ions may be provided by one or more of hydrochloric acid (HCl), sodium chloride (NaCl), potassium chloride (KCl), and copper chloride (CuCl 2 ). Among them, the concentration of the chloride ions (Cl - )) may be 40-100 ppm. By way of example, the concentration of Cl - may be one of 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm or 100 ppm. Of course, the concentration of Cl - may also be other concentrations within 40-100 ppm.

[0050] As an additive, the leveling agent can effectively ensure the flatness of the surface of the second metal layer 40 during electroplating, making the surface of the second metal layer 40 relatively smooth and flat.

[0051] In some feasible implementation manners, the leveling agent can be sodium polydithiopropane sulfonate or glucose.

[0052] 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.

[0053] 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.

[0054] In a specific implementation manner, the concentration of CuSO 4 ·5H 2 O is 200 g / L; the concentration of H 2 SO 4 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, avoiding too high a concentration leading to an increase in the solution viscosity, in this way, the migration speed of ions can be effectively ensured.

[0055] 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 second metal layer 40 is relatively thinner. The smaller the current, the longer the electroplating time, and the second metal layer 40 is relatively thicker.

[0056] Exemplarily, the current can be one of 0.025 A / cm 2 , 0.035 A / cm 2 , 0.045 A / cm 2 , or 0.05 A / cm 2 . Exemplarily, the electroplating time can be one of 6 min, 7 min, 8 min, 9 min, or 10 min.

[0057] In a specific implementation, the current is 0.03 A / cm 2 , and the electroplating time is 8 minutes. In this way, by selecting appropriate current and electroplating time, while ensuring the quality of the coating, the electroplating effect can be improved.

[0058] After step S3 is completed, the structure shown in (d) of Figure 2 can be obtained.

[0059] Of course, in other feasible implementations, the second metal can also be other metals with high thermal conductivity and low coefficient of thermal expansion such as silver. Correspondingly, the electrolyte solution can be adaptively adjusted according to the actual type of the second metal. For example, if the second metal is silver, the electrolyte is a corresponding mixed solution containing silver elements.

[0060] Step S4: Repeat the preparation of the composite structure 50 for N times.

[0061] 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 again.

[0062] In some feasible implementations, 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 interfacial bonding requirements between the heat sinks through the second metal layer 40.

[0063] 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.

[0064] It should be noted that during the preparation process of each composite structure 50, the current magnitude and electroplating time can be the same or different. Among them, the flat surface of the second metal layer 40 can be achieved by the mutual cooperation of the leveling agent and the electroplating current.

[0065] Figure 3 This is the schematic process flow diagram of the preparation of the second composite heat sink provided by the embodiment of the present application. Refer to Figure 3 As shown, after step S4 is completed, the structure shown in (a) of Figure 3 can be obtained.

[0066] Step S5: Remove the protective layer 30 and the first metal layer 20 to obtain the first heat sink structure 60.

[0067] After the preparation of N + 1 composite structures 50 is completed, disconnect the current between the anode and the cathode, and remove the cathode from the electrolyte.

[0068] After removal, the following steps S51 and S52 can be performed.

[0069] Step S51: Peel off the protective layer 30.

[0070] The protective layer 30 can be peeled off from the surface of the first metal layer 20 using a scalpel or tweezers.

[0071] 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.

[0072] 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.

[0073] 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, can corrode the first metal layer 20 relatively quickly, realize the rapid peeling of the first heat sink structure 60, and improve the preparation efficiency.

[0074] After step S5 is completed, the preparation method of the composite heat sink can further include step S53 and step S54.

[0075] Step S53: Clean the first heat sink structure 60 using acetone, alcohol, and deionized water.

[0076] 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.

[0077] Step S54: Dry the first heat sink structure 60.

[0078] In this way, after drying, Figure 3 the structure shown in (b) in

[0079] Step S6: Bond the first heat sink structure 60 with the second heat sink structure 70 to obtain the composite heat sink 100.

[0080] 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 base 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 high axial thermal conductivity, quickly diffuse and transfer heat to the surrounding area, and avoid 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 beneficial to heat transfer between the first heat sink structure 60 and the second heat sink structure 70 and effectively improves the heat dissipation effect.

[0081] After step S6 is completed, the structure shown in (c) in Figure 3 can be obtained.

[0082] 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.

[0083] 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, promote the mutual diffusion and combination of interface atoms, and is beneficial to ensuring the bonding effect. Adopting low-temperature bonding can be carried out in a low-temperature or even room-temperature environment to avoid damage to heat-sensitive materials caused by high temperature. During the actual bonding process, the bonding method can be selected according to the characteristics of the second metal.

[0084] 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.

[0085] 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 completely the surface of the second metal layer 40. And due to the presence of the 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 arranged on the third surface 61, so as to facilitate the heat conduction along the axial direction of the super-aligned single-walled carbon nanotubes 10.

[0086] 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.

[0087] 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. And when it is applied as a heat sink to a semiconductor laser, it can improve the heat conduction rate along 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. Moreover, the preparation method provided by the embodiments of the present application is relatively simple, does not need to damage 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 then ensuring the overall performance of the composite heat sink 100.

[0088] 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.

[0089] Continue to refer to Figure 3 As shown in (c) therein, the composite heat sink 100 includes a first heat sink structure 60, a second heat sink structure 70, and a bonding layer 80.

[0090] 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 above-mentioned preparation method of the 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 above-mentioned preparation method of the composite heat sink.

[0091] Corresponding to the foregoing embodiments of the composite heat sink 100, the present application also provides an embodiment of a semiconductor laser.

[0092] Figure 4 It is a schematic structural diagram of a semiconductor laser provided by an embodiment of the present application.

[0093] 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.

[0094] 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.

[0095] 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 a wide range of usability.

[0096] It should be noted that those skilled in the art will easily think of other implementation manners of the present application after considering the specification and practicing the application disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which 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.

[0097] It should be understood that the present application is not limited to the exact structures 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 method for preparing a composite heat sink, characterized in that: include: 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-ordered single-walled carbon nanotube to form a composite structure of the super-ordered single-walled carbon nanotube and the second metal layer; wherein the electroplating conditions include: the super-ordered single-walled carbon nanotube, the first metal layer and the protective layer serve as a cathode, the second metal serves as an anode, and the cathode and the anode are placed in an electrolyte; Repeat N times to prepare the composite structure; N is a positive integer; removing the protective layer and the first metal layer to obtain a first heat sink structure; The first heat sink structure is bonded to the second heat sink structure to obtain a composite heat sink; wherein the second heat sink structure is a heat sink structure comprising the second metal.

2. The method for preparing a composite heat sink according to claim 1, characterized in that: The removing of the protective layer and the first metal layer comprises: peeling off the protective layer; The entirety of the plurality of composite structures and the first metal layer is placed 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 a composite heat sink according to claim 1, characterized in that: 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 a composite heat sink according to claim 3, characterized in that: The concentration of CuSO4•5H2O is 170-220 g / L; The concentration of H2SO4 is 45-75 g / L; The concentration of the chloride ions is 40-100 ppm.

5. The method for preparing a composite heat sink according to claim 3, characterized in that: The leveling agent includes sodium polydisulfide dipropane sulfonate or glucose; The concentration of the sodium poly(disulfide-bispropanesulfonate) is 10-50 mg / L, and the concentration of the glucose is 2-8 g / L.

6. The method for preparing a composite heat sink according to claim 1, characterized in that: N is greater than or equal to 5 and less than or equal to 20.

7. The method for preparing a composite heat sink according to claim 1, characterized in that: The preparation method of the composite heat sink also includes: The first heat sink structure is cleaned using acetone, alcohol and deionized water in sequence.

8. The method for preparing a composite heat sink according to claim 1, characterized in that: The electroplating conditions also include: the current is 0.025-0.05A / cm 2 , the electroplating time is 6-10min.

9. A composite heat sink, characterized in that: The method for preparing a composite heat sink according to any one of claims 1 to 8 is adopted, wherein the composite heat sink comprises: a first heat sink structure and a second heat sink structure; The first heat sink structure is bonded to the second heat sink structure.

10. A semiconductor laser, characterized in that: comprising a laser chip and the composite heat sink as claimed in claim 9; The laser chip is welded on the first heat sink structure of the composite heat sink.

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