Packaging material for high temperature laser chips

Abstract

The present application relates to chip packaging material technical field, specifically, it relates to high temperature resistant laser chip packaging material, it includes the following raw materials: aluminum nitride ceramic powder, copper tungsten alloy powder, modified hexagonal boron nitride binder, in the present application, modified hexagonal boron nitride is as interface phase, the compatibility and binding force of silane on its surface and phosphate group with aluminum nitride ceramic and copper tungsten alloy powder are enhanced, its lamellar structure can effectively lubricate, relax internal stress in the sintering process, so as to improve the thermal shock resistance and structural density of the packaging body, prevent crack propagation, in addition, the zinc spinel / aluminum nitride gradient functional thin layer prepared by sol-gel method effectively releases thermal stress and improves interface bonding strength, inhibits the harmful interdiffusion of elements at high temperature, so as to ensure higher thermal conductivity while improving the high temperature resistant stability and long-term service reliability of the material.

Description

Technical Field

[0001] This invention relates to the field of chip packaging materials technology, and more specifically, to packaging materials for high-temperature resistant laser chips. Background Technology

[0002] In recent years, with the widespread application of semiconductor laser technology in high-temperature and high-power conditions (such as aerospace, automotive lidar, industrial processing, etc.), higher requirements have been placed on the reliability and performance of its packaging materials. An ideal packaging material needs to have a low coefficient of thermal expansion (CTE) that matches the chip, extremely high thermal conductivity to dissipate heat quickly, excellent high-temperature stability, and good mechanical strength. At present, the industry generally uses advanced ceramics such as AlN and SiC or metal alloys such as CuW and CuMo as packaging substrates or heat sink materials. On the surface of these materials, a silicon dioxide (SiO2) or silicon nitride (SiN) film is usually prepared as a passivation layer by physical vapor deposition (PVD) or thermal oxidation to achieve functions such as electrical insulation, surface protection, and improved solder wettability.

[0003] However, the huge thermal stress generated by the mismatch of the coefficient of thermal expansion (CTE) between the package and the laser chip will produce concentrated shear stress at the interface between the passivation layer and the package substrate during high-temperature operation or thermal cycling, which will lead to cracking of the passivation layer, delamination of the interface and even failure of the entire package structure. In view of this, we propose a packaging material for high-temperature laser chips. Summary of the Invention

[0004] The purpose of this invention is to provide a packaging material for high-temperature resistant laser chips to solve the problem mentioned in the background art that the huge thermal stress caused by the mismatch of the coefficient of thermal expansion (CTE) between the package and the laser chip will generate concentrated shear stress at the interface between the passivation layer and the package substrate during high-temperature operation or thermal cycling, thereby causing the passivation layer to crack, the interface to peel off, and even the failure of the entire package structure.

[0005] This invention provides a packaging material for high-temperature resistant laser chips, comprising the following raw materials: aluminum nitride ceramic powder, copper-tungsten alloy powder, and modified hexagonal boron nitride binder;

[0006] The modified hexagonal boron nitride binder is prepared by grafting 3-aminopropyltriethoxysilane and diisopropyl phosphite onto the surface of hexagonal boron nitride.

[0007] Preferably, the aluminum nitride ceramic powder comprises 30-50 parts by weight, the copper-tungsten alloy powder comprises 10-20 parts by weight, and the modified hexagonal boron nitride binder comprises 10-25 parts by weight.

[0008] Preferably, the modified hexagonal boron nitride binder is prepared as follows:

[0009] Hexagonal boron nitride was sonicated in 90% ethanol for 20-30 minutes, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0010] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 3-Aminopropyltriethoxysilane was added, and the pH was adjusted to 4.0-5.0 with 0.1 mol / L acetic acid. The mixture was stirred at 300-400 rpm for 4 h at 60 °C. Then, diisopropyl phosphite was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed 3-4 times with ethanol, and then vacuum dried at 120 °C for 4-6 h to obtain the modified hexagonal boron nitride binder.

[0011] Preferably, the amount of 3-aminopropyltriethoxysilane added accounts for 1-3% of the mass of hexagonal boron nitride.

[0012] Preferably, the amount of diisopropyl phosphite added accounts for 4-6% of the mass of hexagonal boron nitride.

[0013] Preferably, the packaging material for the high-temperature resistant laser chip is prepared using the following method:

[0014] S1.1 Weigh the following raw materials by weight: 30-50 parts by weight of aluminum nitride ceramic powder, 10-20 parts by weight of copper-tungsten alloy powder, and 10-25 parts by weight of modified hexagonal boron nitride binder.

[0015] S1.2. Place aluminum nitride ceramic powder and copper-tungsten alloy powder in a planetary ball mill and ball mill at 200-300 rpm for 4-6 hours; after ball milling, dry in a vacuum drying oven at 80℃ and pass through a 200-300 mesh sieve to obtain composite powder; place the composite powder and modified hexagonal boron nitride binder in a three-dimensional mixer and dry mix for 2-4 hours to obtain shaped powder;

[0016] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma.

[0017] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0018] S1.4 The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer and an aluminum nitride terminal layer are sequentially deposited by sol-gel spin coating to form a gradient structure. Then, it is heat-treated at 1000-1200℃ for 1-2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0019] Finally, a 50-100nm titanium layer is deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0020] Although the introduction of gradient layers reduces the overall thermal conductivity of the material to some extent, it significantly improves the reliability and long-term stability of the package by mitigating thermal stress, reducing the coefficient of thermal expansion, and improving interfacial bonding.

[0021] Preferably, in step S1.2, the aluminum nitride ceramic powder has a particle size of 0.5-1.5 μm;

[0022] The mass ratio of copper to tungsten in copper-tungsten alloy powder is 10:90-20:80, and the particle size is 1-3μm.

[0023] Preferably, in step S1.2, anhydrous ethanol is used as the grinding medium, zirconia balls are used, and the ball-to-material ratio is 5-10:1.

[0024] Preferably, in step S1.3, the discharge plasma sintering is performed under nitrogen protection, first applying a pre-pressure of 20-30 MPa, then heating to 600-800 °C at a rate of 10-20 °C / min and holding at that temperature and pressure for 20 min; then heating to 1650-1800 °C at a rate of 5-10 °C / min, applying a pressure of 40-50 MPa, and holding at that temperature and pressure for 15-30 min.

[0025] During the discharge plasma sintering process, the copper component (melting point of about 1083°C) in the copper-tungsten alloy forms a liquid phase at a high temperature stage (>1000°C), which promotes particle rearrangement and densification, thus achieving liquid phase sintering; the aluminum nitride and tungsten skeleton remain in the solid state, together forming a composite structure.

[0026] Preferably, in step S1.4, the zinc spinel transition layer uses a zinc spinel sol concentration of 0.3-0.5 mol / L, the precursors are zinc nitrate and aluminum isopropoxide, the molar ratio of zinc to aluminum is 1:2, and the thickness is 300-800 nm.

[0027] The aluminum nitride terminal layer uses an aluminum nitride sol with a concentration of 0.2-0.4 mol / L, an aluminum isopropoxide precursor, and a thickness of 100-300 nm.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] In the packaging material of the high-temperature laser chip of this invention, modified hexagonal boron nitride serves as the interface phase. The silane and phosphate groups on its surface enhance the compatibility and bonding force with aluminum nitride ceramics and copper-tungsten alloy powders. Its layered structure effectively lubricates and relaxes internal stress during sintering, thereby improving the thermal shock resistance and structural density of the package and preventing crack propagation. At the same time, the introduction of modified hexagonal boron nitride can reduce the overall thermal expansion coefficient of the composite material and improve its bending strength, significantly enhancing its compatibility and reliability with the laser chip under high-temperature and thermal cycling conditions. In addition, the zinc spinel / aluminum nitride gradient functional thin layer prepared by the sol-gel method achieves a continuous transition from zinc-rich spinel to aluminum nitride-rich, effectively mitigating thermal stress and improving interfacial bonding strength, inhibiting harmful interdiffusion of elements at high temperatures, thereby comprehensively improving the high-temperature stability and long-term service reliability of the material while ensuring high thermal conductivity. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] This invention provides a packaging material for high-temperature resistant laser chips, comprising the following raw materials: aluminum nitride ceramic powder, copper-tungsten alloy powder, and modified hexagonal boron nitride binder;

[0032] The modified hexagonal boron nitride binder is prepared by grafting 3-aminopropyltriethoxysilane and diisopropyl phosphite onto the surface of hexagonal boron nitride.

[0033] Hexagonal boron nitride was purchased from Changzhou Lima Drying Engineering Co., Ltd., with a purity of ≥99%.

[0034] 3-Aminopropyltriethoxysilane CAS: 919-30-2, Aluminum nitride CAS: 24304-00-5, purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0035] Diisopropyl phosphite, CAS: 1809-20-7, purchased from Wuhan Haorong Biotechnology Co., Ltd.

[0036] Example 1: The preparation process of packaging materials for high-temperature resistant laser chips includes the following steps:

[0037] S1.1 Weigh the following raw materials by weight: 30 parts aluminum nitride ceramic powder, 10 parts copper-tungsten alloy powder, and 10 parts modified hexagonal boron nitride binder.

[0038] S1.2. Aluminum nitride ceramic powder (particle size 0.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 20:80, particle size 1 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 5:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0039] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0040] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0041] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0042] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.3 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 300 nm) and an aluminum nitride terminal layer (using a 0.2 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 100 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, the thin layer is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0043] Finally, a 50nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0044] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0045] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0046] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 1% of 3-aminopropyltriethoxysilane by mass of boron nitride was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Subsequently, 4% of diisopropyl phosphite by mass of boron nitride was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified boron nitride binder.

[0047] Example 2: The preparation process of the packaging material for high-temperature resistant laser chips includes the following steps:

[0048] S1.1 Weigh the following raw materials by weight: 30 parts aluminum nitride ceramic powder, 10 parts copper-tungsten alloy powder, and 10 parts modified hexagonal boron nitride binder.

[0049] S1.2. Aluminum nitride ceramic powder (particle size 0.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 20:80, particle size 1 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 5:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0050] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0051] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0052] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0053] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.3 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 300 nm) and an aluminum nitride terminal layer (using a 0.2 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 100 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, the thin layer is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0054] Finally, a 50nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0055] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0056] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0057] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 2% of 3-aminopropyltriethoxysilane by mass of boron nitride was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Subsequently, 4% of diisopropyl phosphite by mass of boron nitride was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified hexagonal boron nitride binder.

[0058] Example 3: The preparation process of the packaging material for high-temperature resistant laser chips includes the following steps:

[0059] S1.1 Weigh the following raw materials by weight: 30 parts aluminum nitride ceramic powder, 10 parts copper-tungsten alloy powder, and 10 parts modified hexagonal boron nitride binder.

[0060] S1.2. Aluminum nitride ceramic powder (particle size 0.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 20:80, particle size 1 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 5:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0061] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0062] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0063] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0064] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.3 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 300 nm) and an aluminum nitride terminal layer (using a 0.2 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 100 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, the thin layer is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0065] Finally, a 50nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0066] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0067] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0068] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 3-aminopropyltriethoxysilane (3% by mass of boron nitride) was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Then, diisopropyl phosphite (4% by mass of boron nitride) was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified boron nitride binder.

[0069] Example 4: The preparation process of the packaging material for high-temperature resistant laser chips includes the following steps:

[0070] S1.1 Weigh the following raw materials by weight: 30 parts aluminum nitride ceramic powder, 10 parts copper-tungsten alloy powder, and 10 parts modified hexagonal boron nitride binder.

[0071] S1.2. Aluminum nitride ceramic powder (particle size 0.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 20:80, particle size 1 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 5:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0072] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0073] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0074] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0075] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.3 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 300 nm) and an aluminum nitride terminal layer (using a 0.2 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 100 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, the thin layer is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0076] Finally, a 50nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0077] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0078] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0079] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 1% of 3-aminopropyltriethoxysilane by mass of boron nitride was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Subsequently, 5% of diisopropyl phosphite by mass of boron nitride was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified boron nitride binder.

[0080] Example 5: The preparation process of the packaging material for high-temperature resistant laser chips includes the following steps:

[0081] S1.1 Weigh the following raw materials by weight: 30 parts aluminum nitride ceramic powder, 10 parts copper-tungsten alloy powder, and 10 parts modified hexagonal boron nitride binder.

[0082] S1.2. Aluminum nitride ceramic powder (particle size 0.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 20:80, particle size 1 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 5:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0083] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0084] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0085] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0086] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.3 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 300 nm) and an aluminum nitride terminal layer (using a 0.2 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 100 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, the thin layer is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0087] Finally, a 50nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0088] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0089] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0090] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 1% of 3-aminopropyltriethoxysilane by mass of boron nitride was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Then, 6% of diisopropyl phosphite by mass of boron nitride was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified boron nitride binder.

[0091] Surface grafting rate determination: Unmodified hexagonal boron nitride and modified hexagonal boron nitride samples were weighed separately and placed in a TGA instrument. Under a high-purity nitrogen atmosphere (to prevent oxidation), the samples were heated from room temperature to 800℃ at a certain heating rate (e.g., 10℃ / min). The sample weight change curve with temperature was recorded. A temperature range was selected, and the mass retention rates W of the unmodified and modified hexagonal boron nitride samples were obtained. pristine and W modified Calculate the surface grafting rate (%) = [(W modified -W pristine ) / (1-W pristine )]×100%.

[0092] Determination of dispersion stability: Weigh a certain mass (M) total Take a 0.1000 g sample of modified hexagonal boron nitride and place it in a graduated transparent sample bottle (or centrifuge tube). Add a certain volume (e.g., 20 mL) of a specific solvent (e.g., anhydrous ethanol) and ultrasonically disperse it for a certain time (e.g., 30 minutes) to ensure complete homogeneity in its initial state. Let the sample bottle stand at room temperature for 24 hours, avoiding vibration. After standing, carefully pipette a certain volume (e.g., 10 mL) of the upper suspension from a certain depth (e.g., the middle) below the liquid surface. Place the pipette into a pre-dried centrifuge tube and centrifuge at high speed (e.g., 12000 rpm, 20 min) to ensure the suspended hexagonal boron nitride completely settles to the bottom. Carefully discard the supernatant and place the centrifuge tube and precipitate together in a vacuum drying oven to dry to constant weight. After cooling, weigh the total mass of the centrifuge tube and precipitate. Calculate M. suspended =(M tube+sediment )-M tube , of which M tube It is the mass of the empty centrifuge tube, M tube+sediment This is the mass of the precipitate after drying in the centrifuge tube; calculate the suspension rate = M suspended / (M) total / 2)×100%.

[0093] Contact angle determination: Modified hexagonal boron nitride powder was pressed into a flat and dense sheet under the same pressure; a drop of ultrapure water was dropped onto the sample surface using a contact angle measuring instrument; the shape of the water droplet was captured by the instrument's camera, and the contact angle between the water droplet and the sample surface was calculated by the software.

[0094] Table 1 Performance data of modified hexagonal boron nitride binder

[0095] Surface grafting rate Suspension rate after standing for 24 hours Water contact angle Example 1 3.5% 65% 75° Example 2 5.8% 90% 52° Example 3 6.0% 88% 48° Example 4 4.2% 75% 68° Example 5 4.5% 80% 62°

[0096] Comparing Examples 1, 2, and 3, the grafting rate increased significantly with the increase of the amount of 3-aminopropyltriethoxysilane (APTES) (from 3.5% to 6.0%). This is because APTES is the first to be grafted onto the hexagonal boron nitride surface and introduce amine groups, and its amount determines the number of reactive sites. However, the growth is not linear, and the increase is not obvious when it increases from 2% to 3%, indicating that the surface reactive sites are close to saturation.

[0097] Compared with Examples 1, 4, and 5, increasing the amount of diisopropyl phosphite (from 4% to 6%) also improved the grafting rate (from 3.5% to 4.5%); this is because more phosphate molecules reacted with the amino groups on the grafted APTES.

[0098] Example 2 exhibits better dispersion stability (90%) due to its higher grafting rate; the organic long chains on the surface effectively reduce the surface energy of the hexagonal boron nitride sheets, preventing their re-aggregation and sedimentation in the organic medium.

[0099] The dispersion stability of Example 1 was poor (65%) because it had fewer grafted organic molecules and the surface was still close to the original inert state of hexagonal boron nitride, making it easy to settle.

[0100] The stability of Examples 4 and 5 is between the two, and they also follow the rule that the higher the grafting rate, the better the dispersion.

[0101] Unmodified hexagonal boron nitride is hydrophobic with a large water contact angle.

[0102] After modification, the contact angle is significantly reduced; this is because the grafted APTES introduces hydrophilic amine groups, and the phosphate groups of diisopropyl phosphite are also hydrophilic. These polar functional groups increase the surface energy of hexagonal boron nitride, making it easier for it to be wetted by water.

[0103] Examples 2 and 3 have smaller contact angles and stronger hydrophilicity because of the higher density of polar functional groups on their surfaces.

[0104] Example 6: The preparation process of the packaging material for high-temperature resistant laser chips includes the following steps:

[0105] S1.1 Weigh the following raw materials by weight: 50 parts by weight of aluminum nitride ceramic powder, 20 parts by weight of copper-tungsten alloy powder, and 25 parts by weight of modified hexagonal boron nitride binder.

[0106] S1.2. Aluminum nitride ceramic powder (particle size 1.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 10:90, particle size 3 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 10:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0107] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0108] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0109] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0110] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.5 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 300 nm) and an aluminum nitride terminal layer (using a 0.4 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 100 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, the thin layer is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0111] Finally, a 100nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0112] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0113] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0114] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 2% of 3-aminopropyltriethoxysilane by mass of boron nitride was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Subsequently, 4% of diisopropyl phosphite by mass of boron nitride was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified hexagonal boron nitride binder.

[0115] Example 7: The preparation process of the packaging material for high-temperature resistant laser chips includes the following steps:

[0116] S1.1 Weigh the following raw materials by weight: 50 parts by weight of aluminum nitride ceramic powder, 20 parts by weight of copper-tungsten alloy powder, and 25 parts by weight of modified hexagonal boron nitride binder.

[0117] S1.2. Aluminum nitride ceramic powder (particle size 1.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 10:90, particle size 3 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 10:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0118] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0119] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0120] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0121] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.5 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 500 nm) and an aluminum nitride terminal layer (using a 0.4 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 100 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, the thin layer is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0122] Finally, a 100nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0123] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0124] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0125] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 2% of 3-aminopropyltriethoxysilane by mass of boron nitride was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Subsequently, 4% of diisopropyl phosphite by mass of boron nitride was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified hexagonal boron nitride binder.

[0126] Example 8: The preparation process of the packaging material for high-temperature resistant laser chips includes the following steps:

[0127] S1.1 Weigh the following raw materials by weight: 50 parts by weight of aluminum nitride ceramic powder, 20 parts by weight of copper-tungsten alloy powder, and 25 parts by weight of modified hexagonal boron nitride binder.

[0128] S1.2. Aluminum nitride ceramic powder (particle size 1.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 10:90, particle size 3 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 10:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0129] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0130] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0131] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0132] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.5 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 800 nm) and an aluminum nitride terminal layer (using a 0.4 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 100 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, the thin layer is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0133] Finally, a 100nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0134] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0135] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0136] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 2% of 3-aminopropyltriethoxysilane by mass of boron nitride was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Subsequently, 4% of diisopropyl phosphite by mass of boron nitride was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified hexagonal boron nitride binder.

[0137] Example 9: The preparation process of the packaging material for high-temperature resistant laser chips includes the following steps:

[0138] S1.1 Weigh the following raw materials by weight: 50 parts by weight of aluminum nitride ceramic powder, 20 parts by weight of copper-tungsten alloy powder, and 25 parts by weight of modified hexagonal boron nitride binder.

[0139] S1.2. Aluminum nitride ceramic powder (particle size 1.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 10:90, particle size 3 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 10:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0140] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0141] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0142] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0143] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.5 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 300 nm) and an aluminum nitride terminal layer (using a 0.4 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 200 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, it is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0144] Finally, a 100nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0145] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0146] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0147] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 2% of 3-aminopropyltriethoxysilane by mass of boron nitride was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Subsequently, 4% of diisopropyl phosphite by mass of boron nitride was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified hexagonal boron nitride binder.

[0148] Example 10: The preparation process of the packaging material for high-temperature resistant laser chips includes the following steps:

[0149] S1.1 Weigh the following raw materials by weight: 50 parts by weight of aluminum nitride ceramic powder, 20 parts by weight of copper-tungsten alloy powder, and 25 parts by weight of modified hexagonal boron nitride binder.

[0150] S1.2. Aluminum nitride ceramic powder (particle size 1.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 10:90, particle size 3 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 10:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0151] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0152] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0153] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0154] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.5 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 300 nm) and an aluminum nitride terminal layer (using a 0.4 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 300 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, the thin layer is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0155] Finally, a 100nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0156] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0157] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0158] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 2% of 3-aminopropyltriethoxysilane by mass of boron nitride was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Subsequently, 4% of diisopropyl phosphite by mass of boron nitride was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified hexagonal boron nitride binder.

[0159] Thermal conductivity determination: The sintered body is processed into a smooth, parallel circular disc (e.g., Φ12.7mm × 1-3mm thick); a thin layer of graphite is sprayed onto both sides of the sample to enhance its absorption of laser light and emission of infrared signals; the sample is placed in the sample stage of the LFA instrument, with one side irradiated by a short-pulse laser, and the infrared detector on the other side recording the temperature rise curve over time; the software directly calculates the thermal diffusivity (α) of the material based on parameters such as sample thickness and temperature rise curve, and then calculates it using the formula λ = α × ρ × C. p Calculate the thermal conductivity (λ); where ρ is the sample density, C p Specific heat capacity.

[0160] Determination of the coefficient of thermal expansion: The material is processed into a standard rod or strip sample. The sample is placed vertically on the sample holder of the TMA instrument, with the top in contact with a precision displacement sensor, and a very small constant load is applied. The sample is heated in a specific atmosphere (usually N2) at a heating rate of 5℃ / min. The instrument continuously and accurately measures the change in sample length with temperature, plots the length change-temperature curve, and calculates the average coefficient of linear expansion (CTE) within a specified temperature range (e.g., 25-150℃), typically in units of ×10⁻¹⁰. -6 / K.

[0161] Three-point bending strength determination: The sintered body is cut and ground into a long strip test bar of specified dimensions (3mm×4mm×40mm). The test bar is placed on a three-point bending fixture, and the span of the lower support point is adjusted (usually 30mm). A load is applied to the center of the test bar at a constant displacement rate (e.g., 0.5mm / min) until it breaks. The maximum load value (F) is recorded, and the bending strength (σ) is calculated according to the formula: σ=(3FL) / (2bh) 2 ), where F is the maximum load at fracture (N), L is the span of the lower support (mm), b is the width of the test bar (mm), and h is the height of the test bar (mm).

[0162] Table 2 Performance data of packaging materials for high-temperature laser chips

[0163] thermal conductivity coefficient of thermal expansion Three-point bending strength Example 6 168W / (m·K) <![CDATA[6.4×10 -6 / K]]> 425MPa Example 7 162W / (m·K) <![CDATA[6.0×10 -6 / K]]> 445MPa Example 8 155W / (m·K) <![CDATA[5.6×10 -6 / K]]> 420MPa Example 9 165W / (m·K) <![CDATA[6.2×10 -6 / K]]> 415MPa Example 10 160W / (m·K) <![CDATA[6.0×10 -6 / K]]> 405MPa

[0164] The overall thermal conductivity decreases slowly with the increase of the total thickness of the gradient layer (zinc spinel transition layer and aluminum nitride terminal layer).

[0165] The encapsulation substrate itself is a high thermal conductivity material. The thermal conductivity of zinc spinel is much lower than that of the substrate. Although aluminum nitride is a high thermal conductivity phase, the thermal conductivity of the film prepared by the sol-gel method is usually lower than the theoretical value due to grain boundaries and defects. Therefore, covering the surface with a layer of low thermal conductivity zinc spinel is equivalent to increasing the thermal resistance in the heat dissipation path. The greater the thickness, the more obvious the negative impact on the overall heat dissipation capacity (comparative examples 6, 7, 8).

[0166] Increasing the thickness of the aluminum nitride layer (comparative examples 6, 9, 10) has a smaller negative impact on thermal conductivity than increasing the zinc spinel layer.

[0167] The overall average CTE decreases significantly with the increase of the total thickness of the gradient layer.

[0168] The thicker the gradient layer, the greater its control over the thermal expansion behavior of the overall material, thereby more effectively reducing the overall average CTE of the material and making it better matched with the chip (the CTE of Example 8 is lower and the matching is better).

[0169] The strength value first increases slightly and then decreases, with a better thickness range (as in Example 7).

[0170] By moderately increasing the thickness, the gradient layer can more effectively buffer and redistribute the internal stress generated at the interface due to CTE mismatch, reducing stress concentration and thus enabling the material to exhibit higher strength when subjected to bending loads.

[0171] Excessive thickness can introduce more defects (such as microcracks and pores) into an overly thick ceramic coating, and its intrinsic strength is also lower than that of the cermet substrate. At the same time, the interfacial shear stress caused by thermal mismatch between the coating and the substrate will increase with the increase of coating thickness. When this stress exceeds the interfacial bonding strength, it will become a crack initiation, resulting in a decrease in overall strength.

[0172] Example 11: The preparation process of the packaging material for high-temperature resistant laser chips includes the following steps:

[0173] S1.1 Weigh the following raw materials by weight: 40 parts by weight of aluminum nitride ceramic powder, 15 parts by weight of copper-tungsten alloy powder, and 10 parts by weight of modified hexagonal boron nitride binder.

[0174] S1.2. Aluminum nitride ceramic powder (particle size 1.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 10:90, particle size 3 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 10:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0175] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0176] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0177] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0178] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.5 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 500 nm) and an aluminum nitride terminal layer (using a 0.4 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 100 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, the thin layer is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0179] Finally, a 100nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0180] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0181] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0182] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 2% of 3-aminopropyltriethoxysilane by mass of boron nitride was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Subsequently, 4% of diisopropyl phosphite by mass of boron nitride was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified hexagonal boron nitride binder.

[0183] Example 12: The preparation process of packaging materials for high-temperature resistant laser chips includes the following steps:

[0184] S1.1 Weigh the following raw materials by weight: 40 parts by weight of aluminum nitride ceramic powder, 15 parts by weight of copper-tungsten alloy powder, and 18 parts by weight of modified hexagonal boron nitride binder.

[0185] S1.2. Aluminum nitride ceramic powder (particle size 1.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 10:90, particle size 3 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 10:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0186] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0187] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0188] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0189] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.5 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 500 nm) and an aluminum nitride terminal layer (using a 0.4 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 100 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, the thin layer is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0190] Finally, a 100nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0191] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0192] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0193] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 2% of 3-aminopropyltriethoxysilane by mass of boron nitride was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Subsequently, 4% of diisopropyl phosphite by mass of boron nitride was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified hexagonal boron nitride binder.

[0194] Example 13: The preparation process of the packaging material for high-temperature resistant laser chips includes the following steps:

[0195] S1.1 Weigh the following raw materials by weight: 40 parts by weight of aluminum nitride ceramic powder, 15 parts by weight of copper-tungsten alloy powder, and 25 parts by weight of modified hexagonal boron nitride binder.

[0196] S1.2. Aluminum nitride ceramic powder (particle size 1.5 μm) and copper-tungsten alloy powder (copper to tungsten mass ratio 10:90, particle size 3 μm) were placed in a planetary ball mill, using anhydrous ethanol as the milling medium and zirconia balls at a ball-to-particle ratio of 10:1, and milled at 300 rpm for 6 hours. After milling, the powder was dried in a vacuum drying oven at 80℃ and passed through a 200-mesh sieve to obtain the composite powder.

[0197] The composite powder and the modified hexagonal boron nitride binder were placed in a three-dimensional mixer and dry-mixed for 4 hours to obtain the shaped powder.

[0198] S1.3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. Under nitrogen protection, a pre-pressure of 30 MPa is applied first, and then the temperature is raised to 800℃ at a rate of 20℃ / min and held at the temperature and pressure for 20 min. Then the temperature is raised to 1650℃ at a rate of 10℃ / min, a pressure of 50 MPa is applied, and the temperature and pressure are held for 30 min.

[0199] After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature.

[0200] S1.4. The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer (using a 0.5 mol / L zinc spinel sol, with zinc nitrate and aluminum isopropoxide as precursors, a zinc to aluminum molar ratio of 1:2, and a thickness of 500 nm) and an aluminum nitride terminal layer (using a 0.4 mol / L aluminum nitride sol, with aluminum isopropoxide as precursor, and a thickness of 100 nm) are sequentially deposited using a sol-gel spin coating method to form a gradient structure. Subsequently, the thin layer is heat-treated at 1200℃ for 2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate.

[0201] Finally, a 100nm titanium layer was deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

[0202] The preparation method of the modified hexagonal boron nitride binder is as follows:

[0203] Hexagonal boron nitride was sonicated in 90% ethanol for 30 min, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride.

[0204] Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:10. 2% of 3-aminopropyltriethoxysilane by mass of boron nitride was added, and the pH was adjusted to 4.5 with 0.1 mol / L acetic acid. The mixture was stirred at 400 rpm for 4 h at 60 °C. Subsequently, 4% of diisopropyl phosphite by mass of boron nitride was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed three times with ethanol, and then vacuum dried at 120 °C for 6 h to obtain the modified hexagonal boron nitride binder.

[0205] Table 3 Performance data of packaging materials for high-temperature resistant laser chips

[0206] thermal conductivity coefficient of thermal expansion Three-point bending strength Example 11 175W / (m·K) <![CDATA[6.8×10 -6 / K]]> 390MPa Example 12 165W / (m·K) <![CDATA[6.5×10 -6 / K]]> 450MPa Example 13 152W / (m·K) <![CDATA[6.3×10 -6 / K]]> 410MPa

[0207] The thermal conductivity of the material decreases significantly with increasing amount of modified hexagonal boron nitride.

[0208] The lubricating properties of hexagonal boron nitride inhibit the full densification of the matrix material during sintering; the more boron nitride is added, the more micropores and defects there will be inside the material. Pores are poor conductors of heat, which will greatly reduce the overall thermal conductivity.

[0209] Therefore, although hexagonal boron nitride itself has good thermal conductivity, its introduction as an additive usually leads to a decrease in the overall thermal conductivity of the composite material; Example 11 (10 parts) has a higher thermal conductivity.

[0210] The average CTE of the material decreased slowly with increasing amount of modified hexagonal boron nitride.

[0211] Hexagonal boron nitride itself has a low coefficient of thermal expansion. When the content of low CTE hexagonal boron nitride increases, it contributes more to the overall expansion behavior of the material, thereby lowering the average CTE and making it closer to the CTE of the laser chip.

[0212] The flexural strength first increases and then decreases with the increase of hexagonal boron nitride content.

[0213] Appropriate amounts of modified hexagonal boron nitride serve as an interfacial lubricating and toughening phase. Its lamellar structure can effectively deflect, bridge, and terminate the propagation of microcracks, consuming fracture energy and thus significantly improving the fracture toughness and flexural strength of the material.

[0214] Excessive hexagonal boron nitride will excessively hinder sintering densification, resulting in excessive porosity and structural defects inside the material; at the same time, excessively high hexagonal boron nitride content will form continuous weak interfaces, which will become a shortcoming in the mechanical properties of the material, leading to a decrease in strength; the strength of Example 13 (25 samples) has begun to decline.

[0215] Based on the above measurements, Example 12 is selected as the optimal example.

[0216] Comparative Example 1: The difference between this example and Example 12 is that no modified hexagonal boron nitride binder was added.

[0217] Comparative Example 2: The difference between this example and Example 12 is that no modified hexagonal boron nitride binder was added; instead, hexagonal boron nitride was added directly.

[0218] Comparative Example 3: The difference between this example and Example 12 is that no zinc spinel transition layer was added.

[0219] Comparative Example 4: The difference between this example and Example 12 is that no aluminum nitride terminal layer was added.

[0220] Table 4 Performance data of packaging materials for high-temperature resistant laser chips

[0221] thermal conductivity coefficient of thermal expansion Three-point bending strength Example 12 165W / (m·K) <![CDATA[6.5×10 -6 / K]]> 450MPa Comparative Example 1 185W / (m·K) <![CDATA[7.6×10 -6 / K]]> 350MPa Comparative Example 2 160W / (m·K) <![CDATA[6.6×10 -6 / K]]> 380MPa Comparative Example 3 167W / (m·K) <![CDATA[7.2×10 -6 / K]]> 420MPa Comparative Example 4 163W / (m·K) <![CDATA[6.8×10 -6 / K]]> 435MPa

[0222] Comparative Example 1, without the addition of modified hexagonal boron nitride binder, had the highest thermal conductivity, but also the highest CTE and the lowest flexural strength.

[0223] Because the hexagonal boron nitride layers are absent from phonon transmission scattering and obstruction, and because the sintering density is higher and the porosity is less, heat can be conducted more efficiently in the matrix.

[0224] Without the low CTE hexagonal boron nitride phase to lower the average value, the material's CTE is closer to the matrix's value, resulting in a severe mismatch with the chip's CTE.

[0225] The material lacks the toughening mechanism of hexagonal boron nitride (such as crack deflection and bridging), resulting in low crack propagation resistance and exhibiting typical brittle fracture, thus exhibiting the lowest bending strength.

[0226] Comparative Example 2 directly added hexagonal boron nitride, and its thermal conductivity and CTE were similar to those of Example 12, but its flexural strength was significantly lower.

[0227] Unmodified hexagonal boron nitride has an inert surface and extremely poor interfacial bonding with the matrix, resulting in numerous weak interfaces.

[0228] When subjected to loads, cracks are very likely to initiate and propagate at these weak interfaces, which cannot effectively exert the toughening effect of hexagonal boron nitride and instead become a defect in mechanical properties.

[0229] In Comparative Example 3, without the addition of a zinc spinel transition layer, the CTE increased significantly, while the thermal conductivity and strength decreased slightly.

[0230] The increase in CTE is due to the aluminum nitride layer being directly connected to the substrate, lacking a CTE gradient transition. This causes the overall CTE of the material to be closer to the substrate value, making it unable to effectively match the chip and greatly weakening the thermal stress relief effect.

[0231] Its thermal conductivity and strength are slightly reduced because the direct bond between the aluminum nitride terminal layer and the substrate still has a certain stress buffering capacity, but its long-term thermal cycling performance and interface stability are still significantly worse than those of the embodiment with a gradient structure (Example 12).

[0232] In Comparative Example 4, without the addition of an aluminum nitride terminal layer, the CTE increased and the strength decreased slightly.

[0233] Increased CTE: The CTE of zinc spinel is higher than that of aluminum nitride. Therefore, when the terminal layer lacks aluminum nitride with low CTE, the overall CTE will increase and the matching will deteriorate.

[0234] Using zinc spinel directly as the terminal layer will reduce its interfacial bonding strength and high-temperature stability with the chip, thus affecting the overall reliability and manifesting as a slight decrease in strength.

[0235] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A packaging material for a high-temperature resistant laser chip, characterized in that, The raw materials include: 30-50 parts by weight of aluminum nitride ceramic powder, 10-20 parts by weight of copper-tungsten alloy powder, and 10-25 parts by weight of modified hexagonal boron nitride binder. The modified hexagonal boron nitride binder is prepared by grafting 3-aminopropyltriethoxysilane and diisopropyl phosphite onto the surface of hexagonal boron nitride.

2. The packaging material for the high-temperature resistant laser chip according to claim 1, characterized in that, The modified hexagonal boron nitride binder is prepared as follows: Hexagonal boron nitride was sonicated in 90% ethanol for 20-30 minutes, centrifuged, and then vacuum dried at 120℃ to constant weight to obtain dried hexagonal boron nitride. Dry hexagonal boron nitride was dispersed in anhydrous ethanol at a mass ratio of 1:

10. 3-Aminopropyltriethoxysilane was added, and the pH was adjusted to 4.0-5.0 with 0.1 mol / L acetic acid. The mixture was stirred at 300-400 rpm for 4 h at 60 °C. Then, diisopropyl phosphite was added, and the mixture was stirred for another 1 h. After the reaction was completed, the mixture was centrifuged, washed 3-4 times with ethanol, and then vacuum dried at 120 °C for 4-6 h to obtain the modified hexagonal boron nitride binder.

3. The packaging material for the high-temperature resistant laser chip according to claim 2, characterized in that, The amount of 3-aminopropyltriethoxysilane added accounts for 1-3% of the mass of hexagonal boron nitride.

4. The packaging material for the high-temperature resistant laser chip according to claim 2, characterized in that, The amount of diisopropyl phosphite added accounts for 4-6% of the mass of hexagonal boron nitride.

5. The packaging material for the high-temperature resistant laser chip according to claim 1, characterized in that, The preparation method of the packaging material for the high-temperature resistant laser chip is as follows: S1.1 Weigh the following raw materials by weight: 30-50 parts by weight of aluminum nitride ceramic powder, 10-20 parts by weight of copper-tungsten alloy powder, and 10-25 parts by weight of modified hexagonal boron nitride binder. S1.

2. Place aluminum nitride ceramic powder and copper-tungsten alloy powder in a planetary ball mill and ball mill at 200-300 rpm for 4-6 hours; after ball milling, dry in a vacuum drying oven at 80℃ and pass through a 200-300 mesh sieve to obtain composite powder; place the composite powder and modified hexagonal boron nitride binder in a three-dimensional mixer and dry mix for 2-4 hours to obtain shaped powder; S1.

3. The shaped powder is loaded into a graphite mold and sintered by spark plasma. After sintering, the pressure is released when the furnace is cooled to below 600°C, and the sintered body is removed after cooling to room temperature. S1.4 The sintered body is planar ground and cut to the predetermined size using a diamond grinding wheel. In the chip bonding area of ​​the processed package, a zinc spinel transition layer and an aluminum nitride terminal layer are sequentially deposited by sol-gel spin coating to form a gradient structure. Then, it is heat-treated at 1000-1200℃ for 1-2 hours under nitrogen protection to crystallize the thin layer and form a firm bond with the package substrate. Finally, a 50-100nm titanium layer is deposited on the bonding area and pins of the package using magnetron sputtering to obtain the packaging material for the high-temperature resistant laser chip.

6. The packaging material for the high-temperature resistant laser chip according to claim 5, characterized in that, In step S1.2, the aluminum nitride ceramic powder has a particle size of 0.5-1.5 μm; The mass ratio of copper to tungsten in copper-tungsten alloy powder is 10:90-20:80, and the particle size is 1-3μm.

7. The packaging material for the high-temperature resistant laser chip according to claim 5, characterized in that, In step S1.2, anhydrous ethanol is used as the grinding medium, and zirconia balls are used with a ball-to-material ratio of 5-10:

1.

8. The packaging material for the high-temperature resistant laser chip according to claim 5, characterized in that, In step S1.3, the discharge plasma sintering is carried out under nitrogen protection by first applying a pre-pressure of 20-30 MPa, then heating to 600-800 °C at a rate of 10-20 °C / min and holding at that temperature and pressure for 20 min; then heating to 1650-1800 °C at a rate of 5-10 °C / min, applying a pressure of 40-50 MPa, and holding at that temperature and pressure for 15-30 min.

9. The packaging material for the high-temperature resistant laser chip according to claim 5, characterized in that, In S1.4, the zinc spinel transition layer uses a zinc spinel sol concentration of 0.3-0.5 mol / L, the precursors are zinc nitrate and aluminum isopropoxide, the molar ratio of zinc to aluminum is 1:2, and the thickness is 300-800 nm. The aluminum nitride terminal layer uses an aluminum nitride sol with a concentration of 0.2-0.4 mol / L, an aluminum isopropoxide precursor, and a thickness of 100-300 nm.