Laser heat sink and preparation method thereof

Abstract

The invention relates to the technical field of electronic packaging, and discloses a laser heat sink and a preparation method thereof. The laser heat sink comprises a substrate, a silicon layer and an aluminum layer which are sequentially stacked from bottom to top, an aluminum-silicon eutectic phase is arranged between the silicon layer and the aluminum layer, and the thickness of the aluminum layer is 0.05-0.25 mm. According to the invention, the thickness of the aluminum layer in the laser heat sink is reduced, so that the stress generated by the laser heat sink during thermal cycling is reduced, and the number of thermal shock impact resistance times of the laser heat sink can reach more than 3000. Besides, the self-made etching liquid is adopted for etching, the uniformity of the metal side wall can be improved, the smooth and flat aluminum side wall is obtained, and the edge range of the etched aluminum layer is within the range of 5-10 microns.

Description

Technical Field

[0001] The present application belongs to the technical field of electronic packaging, and specifically relates to a laser heat sink and a preparation method thereof. Background Art

[0002] Semiconductor lasers emit a large amount of heat when working. This heat is generally dissipated through the metal and ceramic parts of the heat sink device. When the metal and ceramic transfer this heat, their own temperature will continue to rise, which is not conducive to heat dissipation. At present, the metal parts of semiconductor lasers are mostly made of Cu, and the ceramic parts are mostly made of aluminum nitride (AlN). The thermal conductivity and thermal expansion coefficient of AlN are lower than those of Cu. During the use of laser heat sinks, they are often in a high-frequency switching state, so the laser heat sink is constantly in a high-temperature cycle state, resulting in inconsistent expansion of AlN and Cu. In this case, stress is continuously accumulated between AlN and Cu, and eventually the combination of AlN and Cu fails. In addition, since the laser heat sink has high requirements for the roughness of the metal side wall, it is impossible to obtain a smooth and flat metal side wall by etching with the existing etching solution. Summary of the invention

[0003] In view of this, the present application provides a laser heat sink and a preparation method thereof, which can solve the problem of failure of bonding force between metal and ceramic of the heat sink device under high and low temperature cycle conditions and rough metal side walls.

[0004] In a first aspect, the present application provides a laser heat sink, which includes a substrate, a silicon layer and an aluminum layer stacked in sequence from bottom to top, an aluminum-silicon eutectic phase is included between the silicon layer and the aluminum layer, and the thickness of the aluminum layer is 0.05 to 0.25 mm.

[0005] In some embodiments, the aluminum layer has a thickness of 0.05 to 0.2 mm.

[0006] In some embodiments, the substrate is a ceramic substrate, and the ceramic substrate is selected from one of an aluminum nitride ceramic substrate, an aluminum oxide ceramic substrate, or a silicon carbide ceramic substrate.

[0007] In some embodiments, the thickness of the substrate is 0.5-1 mm.

[0008] In some embodiments, the silicon layer has a thickness of 1 to 10 μm.

[0009] In a second aspect, the present application provides a method for preparing a laser heat sink, the method comprising the following steps:

[0010] S1: providing a substrate;

[0011] S2: coating a silicon layer on the upper surface of the substrate;

[0012] S3: placing an aluminum foil on the upper surface of the silicon layer and performing hot pressing treatment to form an aluminum-silicon eutectic phase between the aluminum foil and the silicon layer, and cooling to obtain an aluminum layer, wherein the thickness of the aluminum layer is 0.05 to 0.25 mm;

[0013] S4: etching the aluminum layer to obtain a laser heat sink.

[0014] In some embodiments, in step S4, the etching solution used for etching includes hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution, and the weight ratio of the hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution is 1:(1~3):(1~3):(1~3):(1~3):(1~3).

[0015] In some embodiments, in step S4, the etching conditions are: temperature of 20 to 60° C., and time of 10 to 50 min.

[0016] In some embodiments, in step S3, the hot pressing conditions include: a pressure of 1 to 10 MPa, a temperature of 600 to 700° C., and a time of 8 to 12 hours.

[0017] In some embodiments, in step S3, the cooling temperature is 300-500°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a laser heat sink prepared in Example 1 of the present application;

[0019] Figure 2 A schematic diagram of a ceramic substrate containing a silicon-aluminum eutectic phase prepared in Example 1 of the present application;

[0020] Figure 3 It is a schematic diagram of the dry film on the laser heat sink after exposure and development in Example 1 of the present application.

[0021] Description of Reference Numerals

[0022] 1-substrate; 2-silicon layer; 3-aluminum layer; 4-dry film. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present application more clear, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

[0024] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the implementation or examples are included in at least one implementation or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same implementation or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more implementations or examples in a suitable manner.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0026] At present, the metal parts of semiconductor lasers are mostly made of Cu, and the ceramic parts are mostly made of aluminum nitride (AlN). The thermal conductivity and thermal expansion coefficient of AlN are lower than those of Cu. During use, the laser heat sink is often in a high-frequency switching state, so the laser heat sink is constantly in a high-temperature cycle, resulting in inconsistent expansion of AlN and Cu. Under such circumstances, stress is continuously accumulated between AlN and Cu, and eventually the combination of AlN and Cu fails. In addition, since the laser heat sink has high requirements for the roughness of the metal side wall, it is impossible to obtain a smooth and flat metal side wall by etching with the existing etching solution.

[0027] To solve the above problems, the present application provides a laser heat sink in the first aspect, such as Figure 1 As shown, the laser heat sink includes a substrate 1, a silicon layer 2 and an aluminum layer 3 stacked in sequence from bottom to top, an aluminum-silicon eutectic phase is included between the silicon layer 2 and the aluminum layer 3, and the thickness of the aluminum layer 3 is 0.05-0.25 mm.

[0028] In the present invention, an aluminum-silicon eutectic phase (Al-Si eutectic phase) is generated between the interface of the silicon layer 2 and the aluminum layer 3. Since the Al-Si eutectic phase has uniform structure, small grains and high hardness, the peel strength of the aluminum layer 3 is increased to 20 MPa.

[0029] In the present invention, the thinner the aluminum layer 3 is, the smaller the stress generated during the thermal cycle of the laser heat sink is. The thickness of the aluminum layer 3 is controlled between 0.05 and 0.25 mm, and within the range of -40°C to 200°C, the stress generated during the thermal cycle of the laser heat sink is small, and the number of thermal shock resistance is high. The present invention reduces the thickness of the aluminum layer in the laser heat sink, thereby reducing the stress generated by the laser heat sink during the thermal cycle, so that the number of thermal shock resistance of the laser heat sink can reach more than 3,000 times.

[0030] In some embodiments, the thickness of the aluminum layer 3 is 0.05-0.2 mm. Specifically, the thickness of the aluminum layer 3 can be 0.05, 0.1, 0.15 or 0.2 mm.

[0031] In some embodiments, the substrate 1 is a ceramic substrate, and the ceramic substrate is selected from one of an aluminum nitride ceramic substrate, an aluminum oxide ceramic substrate, or a silicon carbide ceramic substrate.

[0032] In the above embodiment, since the aluminum nitride ceramic substrate has high thermal conductivity, low dielectric constant and loss, excellent electrical insulation, and a thermal expansion coefficient matching that of silicon and non-toxicity, in a specific embodiment of the present invention, an aluminum nitride (AlN) ceramic substrate is used as the substrate 1.

[0033] In some embodiments, the thickness of the substrate 1 is 0.5-1 mm. Specifically, the thickness of the substrate 1 can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm.

[0034] In some embodiments, the thickness of the silicon layer 2 is 1-10 μm. Specifically, the thickness of the silicon layer 2 may be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm.

[0035] A second aspect of the present application provides a method for preparing a laser heat sink, the method comprising the following steps:

[0036] S1: providing a substrate 1;

[0037] S2: coating a silicon layer 2 on the upper surface of the substrate 1;

[0038] S3: placing an aluminum foil on the upper surface of the silicon layer 2 and performing hot pressing treatment to form an aluminum-silicon eutectic phase between the aluminum foil and the silicon layer, and cooling to obtain an aluminum layer 3, wherein the thickness of the aluminum layer 3 is 0.05 to 0.25 mm;

[0039] S4: etching the aluminum layer 3 to obtain a laser heat sink.

[0040] In the above-mentioned embodiment, the materials used in the second aspect of the present application can be selected with reference to the first aspect of the present application.

[0041] In some embodiments, in step S1 , the size of the substrate 1 may be a conventional choice in the art, for example, the size of the substrate 1 may be 108×108 mm.

[0042] In some embodiments, in step S1, the substrate 1 is an AlN ceramic substrate, and the AlN ceramic substrate is pretreated, and the pretreatment includes grinding, polishing and cleaning performed in sequence.

[0043] In some embodiments, the AlN ceramic substrate is polished using a 2000 mesh sanding belt machine, and the polishing time is 20 to 40 minutes. Specifically, the polishing time may be 20 minutes, 30 minutes, or 40 minutes.

[0044] In some embodiments, the polished AlN ceramic substrate is polished using a polishing liquid, and the polishing liquid can be a conventional choice in the art, such as a nano-diamond polishing liquid purchased from Shanghai Jizhi Biochemical Technology Co., Ltd.

[0045] In some embodiments, the polished AlN ceramic substrate is cleaned with a cleaning liquid for 12 to 15 minutes, specifically, the cleaning time may be 12 minutes, 13 minutes, 14 minutes or 15 minutes.

[0046] In the above embodiment, the cleaning liquid is H 2 SO 4 and H 2 O 2 A mixture of H 2 SO 4 and H 2 O 2 The weight ratio of H is 1:(1.5-4). 2 SO 4 and H 2 O 2 The weight ratio can be 1:1.5, 1:2, 1:3 or 1:4.

[0047] In the above embodiment, H 2 SO 4 The concentration of H 2 O 2 The concentration of H is 3 to 5 wt %. 2 SO 4 The concentration of H may be 3wt%, 4wt% or 5wt%, 2 O 2 The concentration of may be 3 wt%, 4 wt% or 5 wt%.

[0048] In the above embodiment, in step S2 , pure silicon is plated onto the upper surface of the substrate 1 to form the silicon layer 2 .

[0049] In some embodiments, in step S2, physical vapor deposition (PVD) is used for plating, and the plating method is magnetron sputtering deposition or electron beam evaporation.

[0050] In the above embodiment, the coating method is magnetron sputtering deposition, and the conditions of magnetron sputtering deposition include: the vacuum degree is 10 -3 Pa, the holding temperature is 300℃, the voltage is 420V, and the current is 13A.

[0051] In the above embodiment, the aluminum foil and the AlN ceramic substrate with the silicon layer formed thereon are placed in a hot pressing device, and the aluminum foil and the AlN ceramic substrate with the silicon layer formed thereon are hot pressed in a uniaxial direction by the hot pressing device.

[0052] In some embodiments, the thickness of the aluminum foil is 0.05-0.25 mm. Specifically, the thickness of the aluminum foil can be 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm or 0.25 mm.

[0053] In some embodiments, the hot pressing equipment may be a conventional choice in the art, for example, the hot pressing equipment is SPS-1000T-300-ZD, purchased from Nanjing Boyuntong Instrument Technology Co., Ltd.

[0054] In some embodiments, in step S3, the hot pressing conditions include: a pressure of 1 to 10 MPa, a temperature of 600 to 700° C., and a time of 8 to 12 hours. Specifically, the pressure may be 1 MPa, 5 MPa, or 10 MPa, the temperature may be 600° C., 650° C., or 700° C., and the time may be 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours.

[0055] In the above embodiment, to obtain a thinner aluminum layer, the pressure and temperature can be appropriately reduced and the time can be increased. For example, to obtain an aluminum layer with a thickness of 0.05 mm, the pressure should be 1 MPa, the temperature should be 600° C., and the time should be 12 h.

[0056] In the above embodiment, in step S3, the hot pressing is performed in a vacuum environment. The vacuum environment can be a conventional choice in the art. For example, the hot pressing equipment can be evacuated to 10 -4 Pa.

[0057] In some embodiments, in order to prevent the ceramic plate from cracking due to too fast cooling rate, cooling is required at a certain temperature. In step S3, the cooling temperature is 300-500°C. Specifically, the cooling temperature can be 300°C, 400°C or 500°C.

[0058] In the above embodiment, in step S3, an aluminum foil is placed on the upper surface of the silicon layer 2 for hot pressing, and after cooling, an aluminum-silicon eutectic phase is formed between the aluminum foil and the silicon layer to obtain a silicon-aluminum eutectic solder (such as Figure 2 As shown in the figure, aluminum is coated on the AlN ceramic substrate. Since the aluminum-silicon eutectic phase has a uniform structure, small grains and high hardness, the peel strength of the aluminum layer 3 is increased to 20 MPa.

[0059] In some embodiments, in step S4, before etching, a dry film 4 is plated on the surface of the aluminum layer 3 by a photochemical process, then exposed and developed to obtain a desired shape, and then a homemade etching solution is used to etch out the final pattern (such as Figure 3 As shown), and finally remove the dry film with a film stripping solution to obtain the final laser heat sink (as shown Figure 1 shown).

[0060] In the above embodiment, the conditions of the photochemical process are: attaching a photosensitive film (commercially available Changchun Dry Film AF-7075) at 100° C. and a pressure of 100N.

[0061] In some embodiments, in step S4, the etching solution used for etching includes hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution, and the weight ratio of hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution is 1:(1-3):(1-3):(1-3):(1-3):(1-3). Specifically, the weight ratio of hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution can be 1:1:1:1:1:1, 1:1:3:1:1:1 or 1:1:3:3:3:3.

[0062] In the above embodiment, the concentration of the hydrogen chloride solution is 8-10wt%, the concentration of the ammonium chloride solution is 8-10wt%, the concentration of the ferric chloride solution is 25-30wt%, the concentration of the phosphoric acid solution is 8-10wt%, the concentration of the nitric acid solution is 8-10wt%, and the concentration of the acetic acid solution is 8-10wt%. Specifically, the concentration of the hydrogen chloride solution can be 8wt%, 9wt% or 10wt%, the concentration of the ammonium chloride solution can be 8wt%, 9wt% or 10wt%, the concentration of the ferric chloride solution can be 25wt%, 28wt% or 30wt%, the concentration of the phosphoric acid solution can be 8wt%, 9wt% or 10wt%, the concentration of the nitric acid solution can be 8wt%, 9wt% or 10wt%, and the concentration of the acetic acid solution can be 8wt%, 9wt% or 10wt%.

[0063] In some embodiments, in step S4, the etching conditions are: a temperature of 20 to 60° C. and a time of 10 to 50 min. Specifically, the etching temperature may be 20° C., 30° C., 40° C., 50° C. or 60° C., and the etching time may be 10 min, 20 min, 30 min, 40 min or 50 min.

[0064] In the above embodiment, the etching conditions are adopted to quickly complete the etching without damaging the dry film.

[0065] In the above embodiment, in step S4, since the laser heat sink has high requirements on the roughness of the metal side wall, a homemade etching solution is used for etching. Due to the addition of the inhibitor ammonium chloride, the uniformity of the metal side wall can be improved, and a smooth and flat aluminum side wall can be obtained. The edge extremes of the etched aluminum layer 3 are in the range of 5 to 10 μm.

[0066] In the above embodiment, in step S4, the film stripping liquid is one of sodium carbonate, sodium hydroxide, potassium carbonate and potassium bicarbonate.

[0067] The scheme of the present application is described below in conjunction with the following specific examples. Unless otherwise specified, the raw materials used in the following examples are all from common commercial products, and the devices or equipment used are all purchased from conventional market sales channels.

[0068] Aluminum nitride (AlN) ceramic substrate was purchased from Fujian Jingjing New Material Technology Co., Ltd., pure silicon was purchased from Zhongnuo New Material Technology Co., Ltd., and aluminum foil was purchased from Nippon Light Metal Co., Ltd.;

[0069] The polishing liquid was nano-diamond polishing liquid purchased from Shanghai Jizhi Biochemical Technology Co., Ltd.;

[0070] Cleaning fluid (H 2 SO 4 and H 2 O 2 ) was purchased from Nanjing Wanqing Chemical Glass Instrument Co., Ltd. 2 SO 4 and H 2 O 2 The weight ratio is 1:2, H 2 SO 4 The concentration of H 2 O 2 The concentration is 5wt%, and the cleaning time is 15min;

[0071] The hot pressing equipment was SPS-1000T-300-ZD, purchased from Nanjing Boyuntong Instrument Technology Co., Ltd.;

[0072] The conditions of the photochemical process were as follows: attaching a photosensitive film (commercially available Changchun Dry Film AF-7075) at 100°C and a pressure of 100N;

[0073] The etching solution includes hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution, wherein the concentration of hydrogen chloride solution is 10wt%, the concentration of ammonium chloride solution is 10wt%, the concentration of ferric chloride solution is 30wt%, the concentration of phosphoric acid solution is 10wt%, the concentration of nitric acid solution is 10wt%, and the concentration of acetic acid solution is 10wt%; hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution are purchased from Nanjing Wanqing Chemical Glass Instrument Co., Ltd.;

[0074] The film stripping solution (sodium carbonate) was purchased from Nanjing Wanqing Chemical Glass Instrument Co., Ltd.

[0075] Example 1

[0076] This embodiment provides a method for preparing a laser heat sink, comprising the following steps:

[0077] S1: Take an AlN ceramic substrate with a size of 108×108 mm and a thickness of 1 mm as substrate 1, and grind it with a 2000-mesh sand belt of a sanding machine for 30 minutes; then use a polishing liquid to polish the ground AlN ceramic substrate; then use a cleaning liquid to clean the polished AlN ceramic substrate.

[0078] S2: Pure silicon is plated on the upper surface of the cleaned AlN ceramic substrate by magnetron sputtering deposition to obtain a silicon layer 2 (the thickness of the silicon layer 2 is 5 μm, and the conditions for magnetron sputtering deposition include a vacuum degree of 10 -3 Pa, holding temperature is 300°C, voltage is 420V, current is 13A).

[0079] S3: placing an aluminum foil (thickness of 0.05 mm) and an AlN ceramic substrate having a silicon layer 2 formed thereon in a hot pressing device, and performing uniaxial hot pressing on the aluminum foil and the AlN ceramic substrate having a silicon layer 2 formed thereon (the hot pressing conditions include: pressure of 1 MPa, temperature of 600°C, and time of 12 h) to form an aluminum-silicon eutectic phase between the aluminum foil and the silicon layer. The hot pressing is performed in a vacuum environment (evacuated to 10 -4 After the hot pressing is completed, the aluminum layer 3 (such as Figure 2 As shown), the thickness of the aluminum layer 3 is 0.05 mm.

[0080] S4: A dry film is plated on the surface of the aluminum layer 3 by a photochemical process, and then the desired shape is developed by exposure, and then a homemade etching solution (hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution in a weight ratio of 1:3:1:1:1:1) is used to etch (temperature 30°C, time 30min) to obtain the final pattern (such as Figure 3 As shown), and finally use the film stripping liquid (sodium carbonate) to remove the dry film to obtain the final laser heat sink (as shown Figure 1 shown).

[0081] Example 2

[0082] Compared with Example 1, the main difference of Example 2 is that in step S3, the thickness of the aluminum foil is 0.1 mm, and the hot pressing conditions include: pressure of 5 MPa, temperature of 650°C, and time of 8 h, so that the thickness of the aluminum layer 3 is 0.1 mm.

[0083] Example 3

[0084] Compared with Example 1, the main difference of Example 3 is that in step S3, the thickness of the aluminum foil is 0.2 mm, and the hot pressing conditions are: pressure of 10 MPa, temperature of 700°C, and time of 8 h, so that the thickness of the aluminum layer 3 is 0.2 mm.

[0085] Example 4

[0086] Compared with Example 1, the main difference of Example 4 is that, in step S4, the weight ratio of hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution is different, and the weight ratio of hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution is 1:1:1:1:1:1:1.

[0087] Example 5

[0088] Compared with Example 1, the main difference of Example 5 is that, in step S4, the weight ratio of hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution is different, and the weight ratio of hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution is 1:3:3:3:3:3.

[0089] Comparative Example 1

[0090] Compared with Example 1, the main difference of Comparative Example 1 is that in step S3, the aluminum foil is replaced by copper foil.

[0091] Comparative Example 2

[0092] Compared with Example 1, the main difference of Comparative Example 2 is that in step S4, the etching solution is FeCl3 A mixed solution of FeCl 3 The weight ratio of FeCl solution to HCl solution is 1:1. 3 The concentration of the solution was 10 wt %, and the concentration of the HCl solution was 35 wt %.

[0093] Comparative Example 3

[0094] Compared with Example 1, the main difference of Comparative Example 3 is that in step S3, the thickness of the aluminum foil is 0.26 mm, so that the thickness of the aluminum layer 3 is 0.26 mm.

[0095] Comparative Example 4

[0096] Compared with Example 1, the main difference of Comparative Example 4 is that in step S3, the thickness of the aluminum foil is 0.3 mm, so that the thickness of the aluminum layer 3 is 0.3 mm.

[0097] Comparative Example 5

[0098] Compared with Example 1, the main difference of Comparative Example 5 is that in step S3, the thickness of the aluminum foil is 0.04 mm, so that the thickness of the aluminum layer 3 is 0.04 mm.

[0099] Test Example 1

[0100] The peel strength of the aluminum layer in the laser heat sink in Examples 1 to 5 and Comparative Examples 1 to 5 was tested using a 45° peel tester. The results are shown in Table 1 below.

[0101] Table 1

[0102]

[0103]

[0104] Test Example 2

[0105] The thermal shock resistance times of the laser heat sinks in Examples 1 to 5 and Comparative Examples 1 to 5 were tested using an environmental test chamber instrument, and the results are shown in Table 2 below (temperature range is -40°C to 200°C).

[0106] Table 2

[0107] sample Thermal shock resistance (number of times) Example 1 3000 Example 2 3100 Example 3 3100 Example 4 3300 Example 5 3200 Comparative Example 1 1500 Comparative Example 2 3100 Comparative Example 3 2100 Comparative Example 4 1800 Comparative Example 5 2000

[0108] Test Example 3

[0109] The edge extremes of the aluminum layers after laser heat sink etching in Examples 1 to 5 and Comparative Examples 1 to 5 were tested using a scanning electron microscope (SEM). The results are shown in Table 3 below.

[0110] Table 3

[0111]

[0112]

[0113] Analysis of the above results shows that, due to the small radius of Al atoms, the atomic nucleus has a strong attraction to the extranuclear electrons, and the bonding force between the Si atoms of the AlN ceramic substrate and the silicon layer and the Al atoms of the aluminum layer is stronger. Therefore, the peel strength and the number of cold and hot cycle resistance of Examples 1 to 5 are greater than the peel strength and the number of cold and hot cycle resistance of Comparative Example 1.

[0114] When the thickness of the aluminum layer is less than 0.05 mm and greater than 0.25 mm, since the Al atoms in the aluminum layer are stacked too little or too much, it is not conducive to improving the peel strength and the number of cold and hot cycle resistance. Therefore, the peel strength and the number of cold and hot cycle resistance of Examples 1 to 5 are greater than those of Comparative Examples 3 to 5.

[0115] In addition, since the inhibitor ammonium chloride is added to the etching solution, the hydrolysis rate of ammonium ions in the solution is slow, which can reduce the corrosion rate of aluminum, thereby improving the uniformity of the metal side wall and obtaining a smooth and flat aluminum side wall. Therefore, the extreme values ​​of the edges of the aluminum layers of Examples 1 to 5 are all smaller than the extreme values ​​of the edges of the aluminum layers of Comparative Example 2.

[0116] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the principles of the present application should be included in the protection scope of the present application.

Claims

1. A laser heat sink, characterized in that: The laser heat sink comprises a substrate (1), a silicon layer (2) and an aluminum layer (3) which are stacked in sequence from bottom to top, an aluminum-silicon eutectic phase is included between the silicon layer (2) and the aluminum layer (3), and the thickness of the aluminum layer (3) is 0.05 to 0.25 mm.

2. The laser heat sink according to claim 1, characterized in that: The thickness of the aluminum layer (3) is 0.05-0.2 mm.

3. The laser heat sink according to claim 1 or 2, characterized in that: The substrate (1) is a ceramic substrate, and the ceramic substrate is selected from one of an aluminum nitride ceramic substrate, an aluminum oxide ceramic substrate or a silicon carbide ceramic substrate.

4. The laser heat sink according to any one of claims 1 to 3, characterized in that: The thickness of the substrate (1) is 0.5 to 1 mm.

5. The laser heat sink according to any one of claims 1 to 4, characterized in that: The thickness of the silicon layer (2) is 1 to 10 μm.

6. A method for preparing a laser heat sink, characterized in that: The method comprises the following steps: S1: providing a substrate (1); S2: coating a silicon layer (2) on the upper surface of the substrate (1); S3: placing an aluminum foil on the upper surface of the silicon layer (2) and performing a hot pressing process to form an aluminum-silicon eutectic phase between the aluminum foil and the silicon layer, and cooling to obtain an aluminum layer (3), wherein the thickness of the aluminum layer (3) is 0.05 to 0.25 mm; S4: etching the aluminum layer (3) to obtain a laser heat sink.

7. The method according to claim 6, characterized in that In step S4, the etching solution used for etching includes hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution, and the weight ratio of the hydrogen chloride solution, ammonium chloride solution, ferric chloride solution, phosphoric acid solution, nitric acid solution and acetic acid solution is 1:(1~3):(1~3):(1~3):(1~3):(1~3).

8. The method according to claim 6 or 7, characterized in that: In step S4, the etching conditions are: temperature of 20-60° C. and time of 10-50 min.

9. The method according to claim 6, characterized in that In step S3, the hot pressing conditions include: pressure of 1-10 MPa, temperature of 600-700° C., and time of 8-12 h.

10. The method according to claim 6 or 9, characterized in that: In step S3, the cooling temperature is 300-500°C.

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