CN115533739A - Combined tooling for uniform grinding and polishing of ultra-thin coating on the surface of heat sink carrier plate - Google Patents

Abstract

The invention provides a combined tool for uniformly grinding and polishing an ultrathin coating on the surface of a heat sink carrier plate, which comprises a limiting disc, wherein a plurality of through cavities for placing the heat sink carrier plate are arranged on the limiting disc, a pressure uniform pad for uniformly transmitting pressure is arranged above the limiting disc, a pressing block is arranged above the pressure uniform pad, trimming sleeves are sleeved outside the limiting disc, the pressure uniform pad and the pressing block, and the limiting disc, the pressure uniform pad and the pressing block are relatively fixed on the same axis by the trimming sleeves. The roughness of the surface coating of the diamond metal matrix composite material is reduced from the original Ra of more than 3.2 to Ra of less than or equal to 0.2, the requirement of gold-tin welding of a large-size high-power chip is met, and the voidage is less than or equal to 1 percent; the thickness of the plating layer can be uniformly reduced to 5um, so that the influence of the plating layer on the heat conductivity of the diamond metal matrix composite material is reduced; in addition, the method can be implemented on a common metallographic grinder, and has strong applicability and low cost.

Description

Combined tooling for uniform grinding and polishing of ultra-thin coating on the surface of heat sink carrier plate

technical field

The invention relates to the field of grinding technology, in particular to a combined tool for uniform grinding and polishing of an ultra-thin coating on the surface of a heat sink carrier plate.

Background technique

The high-power chips of the third-generation SiC/GaN semiconductors have particularly high requirements for heat dissipation. The high-power chips need to be soldered to the heat sink carrier. The heat sink carrier is generally made of metal-based diamond composite materials such as diamond aluminum (AlC) or diamond copper. , in order to meet the requirements of welding, the surface of metal-based diamond composite heat sink carrier plate must be coated with metal coating. During soldering, in order to ensure that the heat dissipation effect is not affected, the gold-tin welding void rate of such high-power chips on the heat sink carrier should be as close to 0 (generally ≤5%), and the coating of the heat sink carrier is required to be as thin as possible And the surface roughness Ra≤0.2. Because diamond is very hard, the metal-based diamond composite material itself is difficult to grind and polish, and the Ra of the base material can only be around 1.2-1.6; at the same time, the chemical properties of diamond are very stable, and the metal base will be corroded to a certain extent during the surface plating process. , the final surface roughness after plating will further increase to Ra>3.2. In order to ensure that the roughness of the surface coating is Ra≤0.2, the coating is completely covered and the thickness of the coating is as thin as possible, the 15-30 micron thick coating must be uniformly ground and polished to reduce the roughness.

At present, the grinding and polishing method for the ultra-thin coating on the surface of the heat sink carrier plate is generally manual grinding or grinding with a polishing machine.

Manual grinding is to use a hand-held workpiece to press on the sandpaper, perform motion grinding according to linear reciprocating motion or "8" trajectory, and constantly observe the grinding condition of the surface coating. This method can only grind one by one, which is slow and inefficient; and it is prone to uneven force, uneven grinding and thinning of the coating, prone to edge collapse, and damage to the integrity of the coating; in addition, fingers are susceptible to wear

Grinder grinding means using a grinder, and the grinding pad (sandpaper, canvas/velvet pad) is pasted on the grinding disc, and then the workpiece is bonded to the sample loading disc with double-sided tape, paraffin or adhesive, and then a certain pressure is applied to compress it. Grinding on a grinding disc, but due to the difference in flatness, although this method is fast, the grinding plane is also prone to uneven force, uneven grinding and thinning of the coating, prone to collapse, and damage to the integrity of the coating.

Contents of the invention

The purpose of the present invention is to provide a combined tooling for uniform grinding and polishing of the ultra-thin coating on the surface of the heat sink carrier plate, which solves the problem that in the prior art, the grinding plane is easily subjected to uneven force, the coating is ground and thinned unevenly, and the edge is prone to collapse and damage the coating. Complete technical questions.

The invention discloses a combined tooling for uniform grinding and polishing of an ultra-thin coating on the surface of a heat sink carrier plate. A pressure uniform pad for evenly transmitting pressure is arranged above the position disc, a pressing block is arranged above the pressure uniform pad, and a trimming sleeve is provided on the limiting disc, the pressure uniform pad and the jacket of the pressing block, and the trimming sleeve will The limiting disk, the pressure uniform pad and the pressing block are relatively fixed on the same axis.

Working principle: When in use, first fix the grinding pad (sandpaper or canvas/velvet pad) on the grinding disc, then put the heat sink carrier plate into the through cavity of the limiting disc, and then place the pressure uniform pad on the limiting disc Then put the briquetting block on the pressure uniform pad, and finally set the grinding parameters after putting on the dressing sleeve, so that the grinding disc rotates at a speed of 20-40r/min, and the dressing sleeve rotates at the same time. By setting multiple through cavities, multiple heat sink carrier plates can be placed and isolated from each other to improve grinding efficiency. By setting the pressure uniform pad, the pressure of the briquetting block can be evenly pressed on the heat sink carrier plate to ensure that the coating is evenly ground and does not collapse. By arranging the trimming sleeve, which is set on the outside of the limit plate, the pressure uniform pad, and the pressing block, the limit plate, the pressure uniform pad, and the weight pressing block are kept stable and on the same axis.

Further, the limiting disk is circular.

Further, the diameter of the limiting disc is 50-150 mm.

Further, the thickness of the limiting plate is 0.05-0.3 mm smaller than that of the heat sink carrier plate.

By setting the thickness of the limit plate, it can ensure that the pressure exerted by the pressure block on the heat sink carrier plate is slightly larger than that of the limit plate, so as to avoid excessive wear of the limit plate, and avoid excessive sinking of the heat sink carrier plate into the grinding pad, which may cause Sagging.

Further, the gap between the through cavity and the heat sink carrier plate is 0.05-0.2mm.

Further, the interval between adjacent through cavities is 3-20mm.

Further, the flatness and parallelism of the limiting disk are both ≤0.03mm.

By setting the flatness and parallelism of the limit plate, it is ensured that the grinding pad is flattened, and the unevenness of the surface is avoided, resulting in uneven grinding of the coating on the heat sink carrier.

Further, the shape of the pressure uniform pad is adapted to the limit plate.

By setting the shape of the pressure uniform pad, the pressure uniform pad and the limit plate can be more matched.

Furthermore, the thickness of the uniform pressure pad is 3-10mm.

Further, the Brinell hardness of the pressure uniform pad is less than 30.

Further, the pressure uniform pad is a soft and elastic liquid silicone pad, a porous/microporous rubber pad or a latex pad.

Further, the double-sided self-adhesive adhesive film is pasted on both sides of the pressure uniform pad.

By setting the pressure uniform pad with a double-sided self-adhesive film on both sides, the upper and lower self-adhesive fixed pressure blocks, limit plates and heat sink carrier plates ensure stable grinding.

Further, the shape of the pressure block is adapted to the limit plate.

Further, the thickness of the compact is 25-50mm.

Further, the pressing block keeps the pressure on the heat sink carrier plate at 2-4Kpa.

Further, the lower end of the trimming sleeve is evenly distributed with flow grooves.

By setting the flow tank, the internal and external abrasive and water flow are dispersed.

Further, the groove width of the flow cell is 0.5-2mm, and the depth is 1-10mm.

The second purpose of the present invention is to protect a method of using combined tooling for uniform grinding and polishing of an ultra-thin coating on the surface of a heat sink carrier plate. Put the heat sink carrier plate into the through cavity of the limit plate, and then place the pressure uniform pad Then put the pressing block on the pressure uniform pad, and finally set the grinding parameters after putting on the trimming sleeve to make the grinding disc rotate.

Further, when the grinding pad is new sandpaper, the above steps are performed without placing the heat sink carrier plate, and the new sandpaper is leveled and pre-grinded.

By leveling and pre-grinding the new sandpaper, prevent the unevenness of the new sandpaper and the sharp abrasive grains on the surface, which will cause excessive grinding and deep scratches.

Compared with prior art, the beneficial effect that the present invention has is:

1. Solve the problems of rough coating on the surface of the composite material heat sink carrier plate, low efficiency of coating grinding and thinning, unevenness and easy edge collapse. After the implementation of the present invention, the surface coating roughness of the diamond metal matrix composite material is reduced from the original Ra>3.2 to Ra≤0.2, which meets the requirements for gold-tin welding of large-size and high-power chips, and the void rate is ≤1%; the thickness of the coating can be uniformly reduced. It is as thin as 5um, which reduces the influence of coating on the thermal conductivity of diamond metal matrix composites; in addition, it can be implemented on ordinary metallographic grinding machines, with strong applicability and low cost;

2. By setting multiple through cavities, multiple heat sink carrier plates can be placed and isolated from each other to improve grinding efficiency;

3. By setting the thickness of the limit plate, it can ensure that the pressure exerted by the pressure block on the heat sink carrier plate is slightly larger than that of the limit plate, so as to avoid excessive wear of the limit plate, and avoid excessive sinking of the heat sink carrier plate into the grinding pad. causing edge collapse;

4. By setting the pressure uniform pad, the pressure of the briquetting block can be evenly applied to the heat sink carrier plate to ensure that the coating is evenly ground and does not collapse;

5. By setting the trimming sleeve, it is placed outside the limit plate, pressure uniform pad, and pressing block to keep the limit plate, pressure uniform pad, and weight block stable and on the same axis;

6. By setting the flatness and parallelism of the limit plate, ensure that the grinding pad is flattened, and avoid the unevenness of the surface, which will cause uneven grinding of the coating on the heat sink carrier;

7. By setting the shape of the pressure uniform pad, the pressure uniform pad can be more matched with the limit plate;

8. By setting the flow tank, the internal and external abrasives and water flow and disperse.

Description of drawings

Fig. 1 is a schematic diagram of the experimental method of the present invention;

Fig. 2 is a schematic diagram of the experimental method of the present invention;

Fig. 3 is the polishing result diagram of the diamond-aluminum composite material heat sink carrier plate in Example 1 of the present invention;

Fig. 4 is a diagram showing the polishing results of the diamond-aluminum composite material heat sink carrier plate in Example 2 of the present invention.

In the figure: 1-limiting plate, 2-heat sink carrier plate, 3-through cavity, 4-pressure uniform pad, 5-press block, 6-dressing sleeve, 7-flow cell, 8-grinding pad, 9- grinding disc.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments It is some embodiments of the present invention, but not all of them.

Example 1

A combination tool for uniform grinding and polishing of an ultra-thin coating on the surface of a heat sink carrier plate and a use method thereof, the specific structure of which is described in Figures 1-2, and the use method includes the following steps:

Diamond-aluminum composite material heat sink carrier plate, the size is 10*10*2mm, the limit plate is designed according to the size of the heat sink carrier plate, the diameter of the limit plate is 100mm, the internal array of through cavities, the interval between adjacent through cavities is 7.5 mm, the contour dimension of the through cavity is 0.1mm larger than that of the heat sink carrier plate, the thickness of the limit plate is 0.2mm smaller than that of the composite heat sink carrier plate, the flatness and parallelism of the limit plate are 0.03mm, and the limit plate The plate material is made of alloy steel, the hardness RHC≥55 after heat treatment.

The pressure uniform pad has a diameter of 100mm and a thickness of 8mm. The material is made of soft and elastic liquid silicone pad with a Brinell hardness of about 15. The double-sided self-adhesive pad can be fixed well.

The diameter of the compact is 100mm, the thickness is 40mm, and the material is 1Cr18Ni9Ti stainless steel.

Dressing sleeve, the inner diameter of the dressing sleeve is 100.3mm, the outer diameter is 110.3mm, the lower end of the dressing sleeve is evenly divided into grooves, the groove width is 1mm, the depth is 5mm, and the material is 1Cr18Ni9Ti stainless steel;

Grinding process: a) Place the limiting disk on the grinding pad (sandpaper), and choose 3000 mesh new sandpaper; b) Place the pressure uniform pad on the upper surface of the limiting disk; c) Place the pressure block on the pressure uniform pad surface; d) Put the trimming sleeve on the limit plate, pressure uniform pad and briquetting block to form a combination; e) Set the grinding parameters, the grinding disc rotates at a speed of 40r/min, the trimming sleeve rotates at 30r/min, The grinding time is 30s; f) Remove the trimming sleeve, pressing block and pressure uniform pad; g) Place the heat sink carrier plate in the through cavity of the limit plate; h) Place the pressure uniform pad on the limit plate and the heat sink load the upper surface of the plate; i) the piece pressing block is placed on the upper surface of the pressure uniform pad; j) the piece trimming sleeve is placed on the limit plate, the pressure uniform pad and the pressing block to form a combination; k) set the grinding parameters, and the grinding The disk rotates at a speed of 30r/min, while the dressing sleeve rotates at a speed of 20r/min, the grinding time is 30-60s, and water is added during the process; L) then turn over and repeat steps f)-K).

As shown in Figure 3, the surface of the diamond aluminum heat sink is metallized with about 25um of nickel to obtain a surface roughness Ra≤0.15, without any sag around, and the thickness of the coating is reduced to 5-10um.

Example 2

A combination tool for uniform grinding and polishing of an ultra-thin coating on the surface of a heat sink carrier plate and a use method thereof, the specific structure of which is described in Figures 1-2, and the use method includes the following steps:

Diamond-aluminum composite material heat sink carrier plate, the size is 10*10*1mm, the limit plate is designed according to the size of the heat sink carrier plate, the diameter of the limit plate is 100mm, the internal array of through cavities, the interval between adjacent through cavities is 7.5 mm, the contour dimension of the through cavity is 0.05mm larger than the contour dimension of the heat sink carrier plate, the thickness of the limit plate is 0.1mm smaller than the thickness of the composite heat sink carrier plate, the flatness and parallelism of the limit plate are 0.03mm, and the limit plate The plate material is made of alloy steel, the hardness RHC≥55 after heat treatment.

The uniform pressure pad has a diameter of 100mm and a thickness of 5mm. The material is soft and elastic rubber pad with evenly distributed micropores inside, with a Brinell hardness of about 20 and self-adhesive on both sides.

The diameter of the compact is 100mm, the thickness is 40mm, and the material is 1Cr18Ni9Ti stainless steel.

Trim the sleeve, the inner diameter of the trimming sleeve is 100.3mm, the outer diameter is 110.3mm, the lower end of the trimming sleeve is evenly divided into grooves, the groove width is 1mm, the depth is 5mm, and the material is 1Cr18Ni9Ti stainless steel.

Polishing process: as shown in Figure 1-2 below, a) place the limiting plate on the polishing pad (canvas pad); b) place the heat sink carrier plate in the through cavity; c) place the pressure uniform pad on the limiting plate The upper surface of the position plate and the heat sink carrier plate; e) The pressure block is placed on the upper surface of the pressure uniform pad; f) The trimming sleeve is placed on the limit plate, the pressure uniform pad and the pressure block to form a combination; g) Set Polishing parameters, the rotation speed of the grinding disc is 40r/min, while the dressing sleeve rotates at the same time, the rotation speed is 35r/min, the grinding time is 60-120s, add water and spray polishing agent during the process; then turn over and repeat a)-g).

As shown in Figure 4, the surface of the diamond aluminum heat sink is metallized and plated with nickel for about 25um. After treatment, the surface roughness is Ra≤0.1, there is no sag around, and the thickness of the coating is 5-10um.

The above is the implementation manners listed in this embodiment, but this embodiment is not limited to the above optional implementation manners, and those skilled in the art can obtain other various implementation manners according to the above-mentioned manners combined with each other arbitrarily, anyone in this embodiment Various other forms of implementation can be drawn under the inspiration. The above specific implementation methods should not be construed as limiting the protection scope of this embodiment. The protection scope of this embodiment should be defined in the claims, and the description can be used to interpret the claims.

Claims (10)

1. A combined tooling for uniform grinding and polishing of an ultra-thin coating on the surface of a heat sink carrier plate, characterized in that: it includes a limit plate (1), and the limit plate (1) is provided with a plurality of plates for placing heat sink loads. The through cavity (3) of the plate (2), the pressure uniform pad (4) for uniform pressure transmission is arranged above the limit plate (1), and the pressure block (5) is arranged above the pressure uniform pad (4) , the limit plate (1), the pressure uniform pad (4) and the pressing block (5) are provided with a trimming sleeve (6), and the trimming sleeve (6) fixes the limit plate (1), The pressure uniform pad (4) and the briquetting block (5) are relatively fixed on the same axis. 2. The combination tool for uniform grinding and polishing of the ultra-thin coating on the surface of the heat sink carrier plate according to claim 1, characterized in that: the diameter of the limiting plate (1) is 50-150 mm. 3. A combination tool for uniform grinding and polishing of an ultra-thin coating on the surface of a heat sink carrier plate according to claim 1, characterized in that: the thickness of the limiting plate (1) is greater than the thickness of the heat sink carrier plate (2) 0.05 ~ 0.3mm smaller. 4. A combination tool for uniform grinding and polishing of an ultra-thin coating on the surface of a heat sink carrier plate according to claim 1, the gap between the through cavity (3) and the heat sink carrier plate (2) is 0.05-0.2mm . 5 . The combined tooling for uniform grinding and polishing of the ultra-thin coating on the surface of the heat sink carrier plate according to claim 1 , wherein the interval between adjacent through cavities ( 3 ) is 3-20 mm. 6 . 6. A combination tool for uniform grinding and polishing of ultra-thin coating on the surface of heat sink carrier plate according to claim 1, characterized in that: the flatness and parallelism of the limiting plate (1) are both ≤0.03mm. 7. A combined tooling for uniform grinding and polishing of an ultra-thin coating on the surface of a heat sink carrier plate according to claim 1, characterized in that: the shape of the uniform pressure pad (4) is compatible with the limit plate (1) . 8. A combination tool for uniformly grinding and polishing the ultra-thin coating on the surface of the heat sink carrier plate according to claim 1, characterized in that: the shape of the pressing block (5) is compatible with the limiting plate (1). 9. A combination tool for uniformly grinding and polishing the ultra-thin coating on the surface of the heat sink carrier plate according to claim 1, characterized in that flow grooves (7) are uniformly distributed on the lower end of the trimming sleeve (6). 10. A method for using a combined tooling for uniform grinding and polishing of an ultra-thin coating on the surface of a heat sink carrier plate according to any one of claims 1-9, characterized in that: the heat sink carrier plate (2) is placed in a limit position In the through cavity (3) of the disc (1), place the pressure uniform pad (4) on the limit disc (1), then put the pressure block (5) on the pressure uniform pad (4), and finally put it on After trimming the sleeve (6), set the grinding parameters to make the grinding disc (9) rotate.

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