Preparation tool and method of diamond aluminum sheet

Abstract

The application relates to the technical field of diamond aluminum plate preparation, and discloses a preparation tool for diamond aluminum thin plates, which comprises a copper sheath and an aluminum sheath arranged in the copper sheath, the aluminum sheath is in a flat cuboid structure and is made of pure aluminum; a storage cavity is arranged in the aluminum sheath, an annular cavity is formed between the outer side of the aluminum sheath and the inner side of the copper sheath, and the outer side of the aluminum sheath is coated with a heat-resistant isolation layer; a first connecting hole for connecting the storage cavity and the annular cavity is arranged on the side surface of the aluminum sheath, a second connecting hole for connecting the annular cavity is arranged on the side surface of the copper sheath, an air exhaust pipe is arranged in the second connecting hole, and the inner end of the air exhaust pipe is connected with the annular cavity. Meanwhile, a preparation process for the diamond aluminum thin plate is also disclosed. The preparation process and the preparation tool are combined, and the preparation cost of the diamond aluminum thin plate is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of diamond aluminum plate preparation technology, and in particular to a tooling and preparation method for diamond aluminum thin plates. Background Technology

[0002] In the field of chip technology, chip carriers and packaging substrates require materials with low coefficients of thermal expansion and good thermal conductivity. With the development of chip technology and the continuous increase in chip power density, composite materials such as tungsten copper, molybdenum copper, CMC, and CPC can no longer meet the heat dissipation requirements. Currently, some research institutes are using diamond-metal composite materials, such as diamond copper, diamond silver, and diamond aluminum, for chip carriers and packaging substrates. Diamond silver has the highest thermal conductivity, followed by diamond copper, and diamond aluminum has the lowest. Because diamond aluminum has the lowest density (for the same diamond volume fraction), its manufacturing process is relatively simple, and it has a promising market prospect.

[0003] Currently, the common process involves mixing aluminum powder and diamond powder in a specific ratio, loading the mixture into a mold, and hot-pressing it to ensure a tight packing. Diamond aluminum ingots are then produced using the spark plasma method (SPS), and finally, laser cutting is used to slice the ingots into thin sheets for use as chip carriers and packaging substrates. However, this process still suffers from high manufacturing costs; the spark plasma method equipment is expensive, and the subsequent laser cutting is also costly. Summary of the Invention

[0004] In order to solve the above-mentioned problems in the prior art, the present invention provides a tooling and method for preparing diamond aluminum sheets. This method can directly prepare diamond aluminum sheets at a relatively low cost, while eliminating the cost of subsequent laser cutting, which greatly reduces the overall manufacturing cost and has great market application prospects and commercial value.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A tooling for preparing diamond aluminum sheet includes a copper cladding and an aluminum cladding disposed inside the copper cladding. The aluminum cladding has a flat cuboid structure and is made of pure aluminum. The aluminum cladding has a closed storage cavity for filling diamond powder. An annular cavity is formed between the outer side of the aluminum cladding and the inner side of the copper cladding. The outer side of the aluminum cladding is covered with a heat-resistant insulating layer.

[0007] The side of the aluminum sheath is provided with a first connecting hole for connecting the storage chamber and the annular cavity, and the side of the copper sheath is provided with a second connecting hole communicating with the annular cavity. The second connecting hole is provided with an air extraction pipe, and the inner end of the air extraction pipe is communicating with the annular cavity.

[0008] When air is drawn from the outer end of the extraction pipe, the annular cavity and the storage cavity can be evacuated.

[0009] Preferably, the first connecting hole and the second connecting hole are coaxially distributed, the inner end of the suction pipe extends into the first connecting hole and communicates with the discharge chamber, and the side of the suction pipe is provided with a suction hole that communicates with the annular cavity.

[0010] Preferably, the inner end of the vacuum pipe is provided with a tungsten wire mesh or a molybdenum wire mesh. The tungsten wire mesh or molybdenum wire mesh can prevent diamond powder from being extracted during vacuuming.

[0011] Preferably, the copper cladding includes two copper connecting plates. Each connecting plate has a recessed cavity on its side. The edges of the openings of the recesses on the copper connecting plates connect outwards to form connecting surfaces. These connecting surfaces have several connecting holes. When the two connecting plates are fitted together, the two connecting surfaces are connected by bolts. The copper cladding consists of two connected parts, making installation and disassembly more convenient.

[0012] Preferably, the ratio of the sidewall thickness to the bottom thickness of the concave cavity in the copper connecting plate is 1.5-2.5; several ribs are provided at the intersection of the outer side surface and the connecting surface of the copper connector, and the ratio of the height of the ribs to the thickness of the copper connecting plate is 0.3-0.5. The sidewall thickness of the copper connecting plate is greater than the bottom thickness, so that when the copper connecting plate softens and is subjected to internal and external pressure differences, the edge part is not easy to collapse and deform due to its large thickness, and its bottom thickness is smaller, making it easier to be compressed and squeeze liquid pure aluminum; the ribs further increase the edge strength, making it less prone to deformation when softened and compressed, and the height of the ribs is less than the overall thickness, so that when the bottom is compressed, the connection between the bottom and the sidewall can also deform synchronously with the deformation of the bottom, so that the entire bottom surface can be squeezed into liquid pure aluminum.

[0013] Preferably, the heat-resistant insulation layer is an aluminum silicate fiber layer, and the copper cladding is made of T2 copper.

[0014] A process for preparing diamond aluminum sheet includes the following steps:

[0015] s1. Fill the storage cavity of the aluminum sheath with diamond powder from the first connecting hole until the storage cavity is full of diamond powder;

[0016] s2. Wrap the aluminum cladding tightly with a heat-resistant insulating layer, then insert the aluminum cladding into the copper cladding, and connect the exhaust pipe to the second connection hole on the copper cladding.

[0017] s3. Vacuum is drawn through the evacuation pipe until the vacuum level inside the copper cladding reaches 1x10. -2 Pa-1.2x10 -4 Pa, seal the suction pipe;

[0018] s4. Place the copper cladding into a heating furnace and heat it under normal pressure under nitrogen protection. The heating temperature is set at 700-900℃ and the heating time is 5-60 minutes. During the heating process, the aluminum cladding completely melts to form liquid pure aluminum. At the same time, the copper cladding softens under heat and is flattened under the action of internal and external pressure difference. After being pressed, the liquid pure aluminum melts into the diamond powder.

[0019] s5. Remove the copper cladding from the heating furnace and allow it to cool to room temperature. Then, remove the copper cladding and the heat-resistant insulation layer to obtain a diamond aluminum substrate with aluminum coating on both sides. Process the surface of the diamond aluminum substrate to a smooth finish according to the preset dimensions to obtain a diamond aluminum sheet.

[0020] Preferably, in step s1, after the storage cavity is filled with diamond powder, the diamond powder is compacted by vibration until the entire storage cavity is filled with diamond powder tightly.

[0021] This preparation process is simpler, using only conventional vacuum equipment and atmospheric pressure heating equipment, eliminating the need for expensive equipment such as vacuum furnaces, thus significantly reducing equipment costs. It cleverly utilizes vacuuming and atmospheric pressure heating before heating, using the pressure difference to allow the copper cladding to pressure melt and infiltrate liquid pure aluminum, thereby directly obtaining thin-plate diamond aluminum sheets (current technologies produce diamond aluminum billets), thus eliminating the need for a large amount of subsequent laser cutting operations.

[0022] Preferably, in step s3, the vacuum tube is made of T2 copper. After the vacuum is completed, the vacuum tube is first flattened, then the flattened part is bent, and finally the outer end of the vacuum tube is welded and sealed.

[0023] Preferably, in step s5, after removing the copper cladding from the heating furnace, the copper cladding is placed in an ultrasonic wave with a power of 150-250W and a frequency of 80-150 kHz for 3 minutes, and then allowed to cool naturally to room temperature. When the copper cladding is removed from the heating furnace, the interior is still in a liquid state. Through the energy penetration of the ultrasonic waves, the liquid aluminum and diamond powder further permeate and fuse, resulting in a more uniform melting and infiltration of the two particles.

[0024] Therefore, this invention, through ingenious process and simple, specialized tooling, allows the preparation of diamond aluminum sheets to avoid some expensive equipment and can be carried out using ordinary, conventional, and inexpensive equipment, greatly reducing the preparation cost. Attached Figure Description

[0025] Figure 1 This is a structural diagram of a tooling fixture.

[0026] Figure 2 for Figure 1 Exploded view.

[0027] Figure 3This is the first implementation of the air extraction tube.

[0028] Figure 4 This is the second embodiment of the air extraction pipe. Detailed Implementation

[0029] To make the technical problems to be solved, the technical solutions, and the beneficial technical effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and several exemplary embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0030] It should be understood that the terms "first," "second," etc., used herein are for descriptive purposes only and should not be construed as indicating or implying relative importance, nor should they be construed as implicitly specifying the number of technical features indicated. Features specified as "first" or "second" may expressly or implicitly indicate that at least one of those features is included.

[0031] like Figures 1-3 The tooling for preparing diamond aluminum sheets shown includes a copper cladding 1 and an aluminum cladding 2 disposed inside the copper cladding. The aluminum cladding 2 has a flat cuboid structure and is made of pure aluminum. The aluminum cladding 2 has a closed storage cavity 20 for filling diamond powder 3. An annular cavity 22 is formed between the outer side of the aluminum cladding 2 and the inner side of the copper cladding. The outer side of the aluminum cladding is covered with a heat-resistant insulating layer 4. The side of the aluminum cladding 2 has a first connecting hole 21 for connecting the storage cavity 20 and the annular cavity. The side of the copper cladding 1 has a second connecting hole 10 that communicates with the annular cavity. A vacuum pipe 5 is disposed in the second connecting hole, and the inner end of the vacuum pipe communicates with the annular cavity. When the outer end of the vacuum pipe 5 is evacuated, the annular cavity and the storage cavity can be evacuated.

[0032] In some embodiments, such as Figure 4 As shown, the first connecting hole 21 and the second connecting hole 10 are coaxially distributed. The inner end of the suction pipe 5 extends into the first connecting hole and communicates with the discharge chamber. The side of the suction pipe 5 is provided with a suction hole 50 that communicates with the annular cavity. The inner end of the suction pipe 5 is provided with a tungsten wire isolation mesh or a molybdenum wire isolation mesh 6.

[0033] In some embodiments, the heat-resistant insulation layer 4 is an aluminum silicate fiber layer, the copper sheath is made of T2 copper, and the evacuation pipe is also made of T2 copper. After the copper sheath is evacuated to a preset vacuum, the evacuation pipe is first flattened, then the flattened part is bent, and finally the outer end of the evacuation pipe is welded closed. The heat-resistant insulation layer completely isolates the copper sheath from the aluminum sheath to prevent them from sticking together after heating. On the other hand, it also provides insulation for the whole after heating, slows down the cooling rate of the liquid aluminum, and allows the liquid aluminum to better melt and infiltrate with the diamond powder and fuse more fully.

[0034] like Figure 2As shown, the copper sheath 1 includes two copper connecting plates 100. The sides of the copper connecting plates are provided with recesses 101. The edges of the opening ends of the recesses on the copper connecting plates 100 are connected outward to form connecting surfaces 102. The connecting surfaces are provided with a plurality of connecting holes 103. When the connecting plates of the two copper connecting plates are attached, the two connecting surfaces are connected by bolts 104. In some embodiments, the ratio of the sidewall thickness to the bottom thickness of the recess in the copper connecting plate 100 is 1.5-2.5. The outer side of the copper connecting plate and the connecting surface are provided with a plurality of ribs 105. One end of the rib is connected to the connecting surface. The ratio of the height of the rib to the thickness of the copper connecting plate is 0.3-0.5.

[0035] A process for preparing diamond aluminum sheet includes the following steps:

[0036] s1. Fill diamond powder 3 into the storage cavity 20 of aluminum sleeve 2 through the first connecting hole 21. After the storage cavity is filled with diamond powder, vibrate to compact the diamond powder until the entire storage cavity is filled with diamond powder and compacted.

[0037] s2. Wrap the aluminum sheath 2 tightly with the heat-resistant insulating layer 4, then insert the aluminum sheath 2 into the copper sheath 1. Connect the suction pipe 5 to the second connecting hole on the copper sheath. The state at this time is as follows. Figure 3 As shown;

[0038] s3. Vacuum is drawn through the evacuation pipe until the vacuum level inside the copper cladding reaches 1x10. -2 Pa-1.2x10 -4 After evacuation is complete, first flatten the evacuation tube, then bend the flattened part, and finally weld the outer end of the evacuation tube to seal it; the optimal vacuum level is 1.2 x 10⁻⁶. -3 Pa;

[0039] s4. Place the copper cladding in a heating furnace and heat under nitrogen protection at normal pressure. The heating temperature is set at 700-900℃, and the heating time is 5-60 minutes. During the heating process, the aluminum cladding completely melts to form liquid pure aluminum. At the same time, the copper cladding softens under heat and is flattened under the action of internal and external pressure difference. The liquid pure aluminum melts into the diamond powder after being pressed. The preferred heating temperature is set at 800℃, and the heating time is set at 30 minutes.

[0040] s5. Remove the copper cladding from the heating furnace and allow it to cool to room temperature. Then, remove the copper cladding, clean off the heat-resistant insulation layer, and obtain a diamond-coated aluminum substrate with aluminum on both sides. Then, clean the surface of the diamond-coated aluminum substrate...

[0041] In some embodiments, in step s5, after removing the copper cladding from the heating furnace, the copper cladding is placed in an ultrasonic wave with a power of 150-250W and a frequency of 80-150 kHz for 3 minutes, and then allowed to cool naturally to room temperature. Preferably, the ultrasonic wave has a power of 200W and a frequency of 120kHz.

[0042] This invention utilizes a clever process combined with simple yet specialized tooling. By leveraging the softening of a copper cladding and the internal and external pressure difference, molten pure aluminum is infiltrated into diamond powder, causing the liquid aluminum and diamond powder to fuse together. The tooling used in this process is extremely simple, avoiding expensive equipment and significantly reducing manufacturing costs. The final product is a diamond-coated aluminum sheet, eliminating the need for laser cutting of diamond-coated aluminum ingots. This type of diamond-coated aluminum sheet has low production costs and significant market application prospects and commercial value.

[0043] In the description of this invention, it should be understood that the directions or positional relationships indicated by up, down, left, right, inner end, outer end, one end, and the other end are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the purpose of more clearly describing the technical solutions of this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting this invention.

[0044] Although specific embodiments of the invention have been described in detail herein, they are given for illustrative purposes only and should not be construed as limiting the scope of the invention. Various substitutions, alterations, and modifications can be conceived without departing from the spirit and scope of the invention.

Claims

1. A tooling for preparing diamond aluminum sheets, characterized in that, It includes a copper sheath and an aluminum sheath disposed inside the copper sheath. The aluminum sheath has a flat cuboid structure and is made of pure aluminum. The aluminum sheath has a closed storage cavity for filling diamond powder. An annular cavity is formed between the outer side of the aluminum sheath and the inner side of the copper sheath. The outer side of the aluminum sheath is covered with a heat-resistant insulating layer. The side of the aluminum sheath is provided with a first connecting hole for connecting the storage chamber and the annular cavity, and the side of the copper sheath is provided with a second connecting hole communicating with the annular cavity. The second connecting hole is provided with an air extraction pipe, and the inner end of the air extraction pipe is communicating with the annular cavity. When air is drawn from the outer end of the extraction pipe, the annular cavity and the storage cavity can be evacuated. The copper sheath includes two copper connecting plates. The sides of the copper connecting plates are provided with recesses. The edges of the opening ends of the copper connecting plates at the recesses are connected outward to form connecting surfaces. Several connecting holes are provided on the connecting surfaces. When the two copper connecting plates are fitted together, the two connecting surfaces are connected by bolts. The ratio of the sidewall thickness to the bottom thickness of the recess in the copper connecting plate is 1.5-2.

5. Several ribs are provided at the intersection of the outer side of the copper connecting plate and the connecting surface. The ratio of the height of the ribs to the thickness of the copper connecting plate is 0.3-0.

5.

2. The tooling for preparing diamond aluminum sheets according to claim 1, characterized in that, The first connecting hole and the second connecting hole are coaxially distributed. The inner end of the suction pipe extends into the first connecting hole and communicates with the storage chamber. The side of the suction pipe is provided with a suction hole that communicates with the annular cavity.

3. The tooling for preparing diamond aluminum sheets according to claim 2, characterized in that, The inner end of the extraction pipe is equipped with a tungsten wire isolation mesh or a molybdenum wire isolation mesh.

4. The tooling for preparing diamond aluminum sheets according to claim 1, characterized in that, The heat-resistant insulation layer is an aluminum silicate fiber layer, and the copper sheath is made of T2 copper.

5. A process for preparing diamond-coated aluminum sheets, using the preparation tooling described in any one of claims 1-4, characterized in that, Includes the following steps: s1. Fill the storage cavity of the aluminum sheath with diamond powder from the first connecting hole until the storage cavity is full of diamond powder; s2. Wrap the aluminum cladding tightly with a heat-resistant insulating layer, then insert the aluminum cladding into the copper cladding, and connect the exhaust pipe to the second connection hole on the copper cladding. s3. Vacuum is drawn through the evacuation pipe until the vacuum level inside the copper cladding reaches 1x10. -2 Pa-1.2x10 -4 Pa, seal the suction pipe; s4. Place the copper cladding into a heating furnace and heat it under normal pressure under nitrogen protection. The heating temperature is set to 700-900℃ and the heating time is 5-60 minutes. During the heating process, the aluminum cladding completely melts to form liquid pure aluminum. At the same time, the copper cladding softens under heat and is flattened under the action of internal and external pressure difference. The liquid pure aluminum melts into the diamond powder after being pressed. s5. Remove the copper cladding from the heating furnace and allow it to cool to room temperature. Then, remove the copper cladding and the heat-resistant insulation layer to obtain a diamond aluminum substrate with aluminum coating on both sides. Process the surface of the diamond aluminum substrate to a smooth finish according to the preset dimensions to obtain a diamond aluminum sheet.

6. The preparation process of a diamond aluminum sheet according to claim 5, characterized in that, In step s1, after the storage cavity is filled with diamond powder, the diamond powder is compacted by vibration until the entire storage cavity is filled with diamond powder.

7. The preparation process of a diamond aluminum sheet according to claim 5, characterized in that, In step s3, the vacuum tube is made of T2 copper. After the vacuum is completed, the vacuum tube is first flattened, then the flattened part is bent, and finally the outer end of the vacuum tube is welded and sealed.

8. The preparation process of a diamond aluminum sheet according to claim 5, characterized in that, In step s5, after removing the copper cladding from the heating furnace, the copper cladding is placed in an ultrasonic wave with a power of 150-250W and a frequency of 80-150 kHz for 3 minutes, and then allowed to cool naturally to room temperature.

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