Wafer coating device

Abstract

The present invention belongs to the field of semiconductor packaging technology, and specifically relates to a wafer coating device, including a pressure component, an upper mold base and a pressure head component, the pressure head component includes a pressing plate for pressing down the wafer, a heating plate fixed above the pressing plate and used for heating the wafer, a force transmission plate for receiving the pressure applied by the pressure component, and a buffer plate located between the force transmission plate and the heating plate and used for buffering the pressure applied to the force transmission plate, the four are coaxially fixed and the cross-sectional area of ​​the buffer plate is smaller than the cross-sectional area of ​​the force transmission plate and the heating plate, the bottom surface of the force transmission plate includes a force transmission plane located in the middle and an avoidance slope located on the periphery of the force transmission plane to avoid the heating plate; the present invention utilizes the buffer plate to uniformly transmit the pressure from the pressure component to the pressing plate to uniformly press the wafer, thereby achieving uniform coating, and the avoidance slope of the force transmission plate enables the thickness of the force transmission plate to gradually increase from the end to the center, which not only avoids the deformation of the force transmission plate itself, but also meets the imprinting requirements of the workpiece.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor packaging, and in particular relates to a wafer coating device. Background Art

[0002] In the semiconductor manufacturing process, a thin film needs to be formed on the semiconductor wafer. The film thickness is easily uneven during the film forming process, which reduces the yield of circuit components. The problem of uneven film thickness is due to the uneven temperature and pressure on the surface of the wafer when the wafer is heated. Therefore, how to keep the temperature and pressure on the surface of the wafer uniform during the film forming process is a very important issue. Summary of the invention

[0003] The technical problem to be solved by the present invention is: in order to solve the problem in the prior art that semiconductor wafers are prone to uneven film thickness during film forming, which reduces the yield of circuit components, a wafer coating device is now provided.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a wafer coating device, comprising:

[0005] There are multiple pressure-applying assemblies, each of which includes a slidably arranged piston and a corresponding pressure rod;

[0006] An upper die seat for mounting a pressure assembly, the interior of which is provided with a plurality of piston holes for mounting pistons and an air cavity connected with the plurality of piston holes to drive the pistons in the piston holes to move downward when ventilated;

[0007] And a pressure head assembly, including a pressing plate for pressing down a wafer, a heating plate fixed above the pressing plate and used for heating the wafer, a force transmission plate for receiving the pressure applied by the pressure-applying assembly, and a buffer plate located between the force transmission plate and the heating plate and used for buffering the pressure applied to the force transmission plate. The four are coaxially fixed and the cross-sectional area of ​​the buffer plate is smaller than the cross-sectional areas of the force transmission plate and the heating plate. The bottom surface of the force transmission plate includes a force transmission plane located in the middle to fit with the buffer plate and an avoidance slope located on the periphery of the force transmission plane to avoid the heating plate, and the avoidance slope gradually tilts upward from the force transmission plane to the direction of the avoidance slope.

[0008] Furthermore, the upper die seat comprises a top plate, a middle plate and a base fixed in sequence from top to bottom, the top plate and the middle plate enclose the piston hole and the air cavity, and the base is provided with a slide groove for installing the pressure rod;

[0009] The top surface of the middle plate is concave to form a concave area, a pressure plate is embedded in the concave area, and a piston seal sleeved on the outside of the piston is pressed between the pressure plate and the middle plate.

[0010] Furthermore, the center part of the top surface of the middle plate is recessed to form a first lower recessed portion, and the center part of the bottom surface of the top plate is recessed to form a first upper recessed portion, a first pressure block is embedded between the first upper recessed portion and the first lower recessed portion, a first upper sealing member is pressed between the first pressure block and the top plate, a first lower sealing member is pressed between the first pressure block and the middle plate, and the first pressure block has a radially protruding abutting portion for abutting against the pressure plate, and the top plate, the first pressure block and the middle plate are fixed by a first bolt.

[0011] Furthermore, the first bolt includes a main bolt located in the center and a plurality of sub-bolts surrounding the main bolt, the main bolt is screwed in from top to bottom, and the sub-bolts are screwed in from bottom to top.

[0012] Furthermore, the cross section of the first pressing block is a special-shaped arc surface formed by connecting a plurality of convex arc surfaces end to end, and the cross sections of the first upper recessed portion and the first lower recessed portion both match the cross-sectional shape of the first pressing block.

[0013] Furthermore, the outer portion of the top surface of the middle plate is recessed to form a plurality of second lower recessed portions, the outer portion of the bottom surface of the top plate is recessed to form a plurality of second lower recessed portions, the plurality of second upper recessed portions correspond to the plurality of second lower recessed portions one by one, and a second pressure block is embedded between each second upper recessed portion and the corresponding second lower recessed portion, a second upper sealing member is embedded between each second pressure block and the top plate, a second lower sealing member is embedded between each second pressure block and the middle plate, and the top plate, the second pressure block and the middle plate are fixed by second bolts.

[0014] Further, the plurality of pressure components are divided into at least two groups, namely a first pressure component and a second pressure component located outside the first pressure component, the first pressure component includes a plurality of first pistons and first pressure rods corresponding to the first pistons, and the second pressure component includes a plurality of second pistons and second pressure rods corresponding to the second pistons;

[0015] The piston hole includes a plurality of first piston holes for installing the first piston and a plurality of second piston holes for installing the second piston. The air cavity includes a first air cavity connected with the plurality of first piston holes and a second air cavity connected with the plurality of second piston holes and isolated from the first air cavity.

[0016] Furthermore, a third seal and a fourth seal arranged around the third seal are pressed between the middle plate and the top plate, and the pressure plate includes a first pressure plate and a second pressure plate arranged around the first pressure plate, the inner peripheral wall of the third seal, the outer peripheral wall of the first upper seal, the outer peripheral wall of the second upper seal, the bottom surface of the top plate and the top surface of the first pressure plate together form the above-mentioned first air cavity, and the outer peripheral wall of the third seal, the inner peripheral wall of the fourth seal, the bottom surface of the top plate and the top surface of the second pressure plate together form the above-mentioned second air cavity.

[0017] Furthermore, the cross-sectional area of ​​the force transmission plane is larger than the cross-sectional area of ​​the buffer plate, and a step surface is formed between the force transmission plane and the avoidance slope.

[0018] Furthermore, there are a plurality of pressure rods in the same pressure assembly, the plurality of pressure rods are distributed vertically and the top of each pressure rod is configured as an upwardly convex arc surface;

[0019] The base includes a first insulation board having a first lower protrusion, a second insulation board having a second lower protrusion, and a connecting plate connected therebetween; a first insulation cavity is formed between the bottom surface of the first insulation board and the top surface of the connecting plate; a second insulation cavity is formed between the bottom surface of the second insulation board and the top surface of the force transmission plate.

[0020] The beneficial effects of the present invention are as follows: the present invention utilizes the buffer plate to evenly transfer the pressure from the pressure-applying assembly to the crimping plate to evenly apply pressure to the wafer, thereby achieving uniform coating, and the avoidance slope of the force transmission plate enables the thickness of the force transmission plate to gradually increase from the end to the center, thereby avoiding deformation of the force transmission plate itself and meeting the imprinting requirements of the workpiece.

[0021] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0023] Figure 1 It is a three-dimensional structural diagram of the present invention;

[0024] Figure 2 is a top view of the present invention;

[0025] Figure 3 yes Figure 2 Sectional view in the AA direction;

[0026] Figure 4 yes Figure 3 A partial enlarged view of part E in the middle;

[0027] Figure 5 yes Figure 2 Cross-sectional view in the BB direction;

[0028] Figure 6 yes Figure 5 A partial enlarged view of part F in the middle;

[0029] Figure 7 is a bottom view of the present invention;

[0030] Figure 8 yes Figure 7Cross-sectional view in CC direction;

[0031] Fig. 9 yes Figure 7 Cross-sectional view in the middle DD direction;

[0032] Fig.10 is a top view of the present invention after removing the top plate;

[0033] Fig.11 It is a three-dimensional structural diagram of the present invention after removing the top plate;

[0034] Fig.12 is a bottom view of the top plate of the present invention;

[0035] Fig.13 is a three-dimensional structural diagram of the first pressing block in the present invention;

[0036] Fig.14 It is an embossing diagram without a buffer plate;

[0037] Fig.15 It is an imprint diagram for setting the buffer plate.

[0038] In the figure:

[0039] 1. Pressure assembly; 101. Piston; 101a. First piston; 101b. Second piston; 102. Pressure rod; 102a. First pressure rod; 102b. Second pressure rod;

[0040] 2. Upper die seat; 201. Piston hole; 201a. First piston hole; 201b. Second piston hole; 202. Air cavity; 202a. First air cavity; 202b. Second air cavity; 203. Top plate; 2031. First upper recess; 2032. Second upper recess; 204. Intermediate plate; 2041. Recessed area; 2042. First lower recess; 2043. Second lower recess; 205. Base; 2051. First heat insulation board; 2051a. First lower protrusion; 2051b. Connecting groove; 2052. Second heat insulation board; 2052a. Second lower protrusion; 2053, connecting plate; 2054, first heat insulation cavity; 2055, second heat insulation cavity; 206, pressing plate; 206a, first pressing plate; 206b, second pressing plate; 207, piston seal; 208, first pressing block; 2081, abutment portion; 209, first upper seal; 210, first lower seal; 211, main bolt; 212, sub-bolt; 213, second pressing block; 214, second upper seal; 215, second lower seal; 216, second bolt; 217, third seal; 218, fourth seal; 219, connecting rod; 220, connecting block;

[0041] 3. Press head assembly; 301. Pressing plate; 302. Heating plate; 303. Force transmission plate; 3031. Force transmission plane; 3032. Avoidance slope; 3033. Step surface; 304. Buffer plate;

[0042] 4. Membrane separation assembly; 401. Separation rod; 402. Elastic member; 403. Separation ring. DETAILED DESCRIPTION

[0043] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner only, and therefore only show the components related to the present invention, and directions and references (e.g., up, down, left, right, etc.) may only be used to help describe the features in the drawings. Therefore, the following specific embodiments are not to be taken in a limiting sense, and the scope of the subject matter claimed is limited only by the attached claims and their equivalents.

[0044] like Figure 1 and Figure 2 As shown, a wafer coating device comprises:

[0045] The pressure applying assembly 1 has a plurality of components, each comprising a slidably arranged piston 101 and a corresponding pressure rod 102;

[0046] The upper die base 2 for mounting the pressure assembly 1 has a plurality of piston holes 201 for mounting the pistons 101 and an air cavity 202 connected with the plurality of piston holes 201 to drive the pistons 101 in the piston holes 201 to move downward when ventilated. The plurality of pistons 101 correspond to the plurality of piston holes 201 one by one and each piston 101 is slidably mounted in its corresponding piston hole 201. Gas enters the plurality of piston holes 201 through the air cavity 202 to push the pistons 101 in the piston holes 201 to move downward, and the pistons 101 push the corresponding pressure rods 102 to move downward. Figure 3 and Figure 5 As shown;

[0047] And the pressure head assembly 3, including a pressing plate 301 for pressing down the wafer, a heating plate 302 fixed above the pressing plate 301 and used for heating the wafer, a force transmission plate 303 for receiving the pressure applied by the pressure-applying assembly 1, and a buffer plate 304 located between the force transmission plate 303 and the heating plate 302 and used for buffering the pressure on the force transmission plate 303. The four are coaxially fixed by screws, and the force transmission plate 303, the buffer plate 304 and the heating plate 302 are fixed by a central screw inserted in the center thereof, which avoids the offset between the various components to the greatest extent and saves installation time. The heating plate 302 and the pressing plate 301 are fixed by side screws located at the edge, such as Figure 3 and Figure 5 shown.

[0048] A heating element is installed in the heating plate 302, and the heat generated by the heating element is transferred to the wafer through the heating plate 302 and the pressing plate 301 to meet the heating requirements of the wafer; a plurality of pressure rods 102 are densely distributed above the force transmission plate 303 to transfer the pressure applied by the piston 101 to the force transmission plate 303;

[0049] The cross-sectional area of ​​the buffer plate 304 is smaller than the cross-sectional areas of the force transmission plate 303 and the heating plate 302, that is, the buffer plate 304 is located at the inner periphery of the force transmission plate 303, forming an I-shaped structure. The buffer plate 304 has a certain elasticity and has the characteristics of high temperature resistance and heat insulation. It is preferably made of PTFE material, which has a larger thermal expansion coefficient to alleviate the thermal stress received from the heating plate 302. The elastic properties it possesses can evenly transfer the pressure from the pressure rod 102 to the heating plate 302, and then to the crimping plate 301, playing an intermediate transition role, such as Fig.14 and Fig.15 As shown, when the buffer plate 304 is not provided, the pressure will be concentrated in the peripheral area, the pressure in the peripheral area is greater than the pressure in the central area, and the pressure is very uneven. After the buffer plate 304 is provided, the pressure in the peripheral area and the pressure in the central area remain balanced.

[0050] The bottom surface of the force transmission plate 303 includes a force transmission plane 3031 located in the middle to fit with the buffer plate 304 and an avoidance slope 3032 located outside the force transmission plane 3031 to avoid the heating plate 302, and the avoidance slope 3032 gradually inclines upward from the force transmission plane 3031 to the avoidance slope 3032, that is, the thickness of the force transmission plate 303 gradually increases from the end to the center. The pressure transmitted from the force transmission plate 303 to the buffer plate 304 needs to be maintained within a constant range. If it is too large, it will cause damage to the workpiece, and if it is too small, the workpiece will not be completely imprinted. If a thinner regular disc-shaped force transmission plate 303 is used, the stress applied to the buffer plate 304 is small, which cannot meet the imprinting requirements of the workpiece, and it is easy to cause the force transmission plate 303 to bend too much due to different materials, making the end of the force transmission plate 303 closer to the heating plate 302. Using a thicker force transmission plate 303 will increase the cost. This solution uses the avoidance slope 3032 to achieve a gradual increase in the thickness of the force transmission plate 303 from the end to the center, thereby avoiding the deformation of the force transmission plate 303 itself to the greatest extent and meeting the imprinting requirements of the workpiece.

[0051] In some examples, such as Figure 3 and Figure 5 As shown, the upper die base 2 includes a top plate 203, a middle plate 204 and a base 205 which are fixed in sequence from top to bottom. The top plate 203 and the middle plate 204 enclose the piston hole 201 and the air cavity 202. The base 205 is provided with a slide groove for installing the pressure rod 102.

[0052] like Figure 4As shown, the top surface of the middle plate 204 is recessed to form a recessed area 2041, and a pressure plate 206 is embedded in the recessed area 2041. The piston seal 207 sleeved on the outside of the piston 101 is pressed between the pressure plate 206 and the middle plate 204. The pressure plate 206 can press multiple piston seals 207 at the same time, thereby improving assembly efficiency.

[0053] In some examples, such as Figure 4 As shown, the center of the top surface of the middle plate 204 is recessed to form a first lower recess 2042, the center of the bottom surface of the top plate 203 is recessed to form a first upper recess 2031, a first pressing block 208 is embedded between the first upper recess 2031 and the first lower recess 2042, a first upper sealing member 209 is pressed between the first pressing block 208 and the top plate 203, a first lower sealing member 210 is pressed between the first pressing block 208 and the middle plate 204, and the first upper sealing member 209 and the first lower sealing member 211 are pressed between the first pressing block 208 and the middle plate 204. 10 can separate the air cavity 202 from the first upper recessed portion 2031 and the first lower recessed portion 2042 to ensure the airtightness of the air cavity 202; the first pressing block 208 radially protrudes with an abutting portion 2081 for abutting against the pressing plate 206, and the abutting portion 2081 can press the pressing plate 206, and the top plate 203, the first pressing block 208 and the middle plate 204 are fixed by the first bolt, and the top plate 203 and the middle plate 204 are limited and clamped from the center to avoid air leakage after the top plate 203 swells, which leads to failure of the crimping.

[0054] In some examples, such as Figure 4 As shown, the first bolt includes a main bolt 211 located in the center and a plurality of sub-bolts 212 surrounding the main bolt 211, the nominal diameter of the main bolt 211 is larger than the nominal diameter of the sub-bolt 212, the main bolt 211 is screwed in from top to bottom, the top plate 203 is provided with a countersunk hole for accommodating the nut of the main bolt 211, the sub-bolt 212 is screwed in from bottom to top, the base 205 is provided with a first avoidance hole for avoiding the nut of the sub-bolt 212, the main bolt 211 and the sub-bolt 212 are screwed in from different directions respectively to improve the connection strength between the top plate 203 and the middle plate 204.

[0055] In some examples, such as Fig.13 As shown, the cross-section of the first pressing block 208 is a special-shaped arc surface formed by connecting multiple convex arc surfaces end to end, which is approximately in the shape of petals. The number of convex arc surfaces corresponds to the number of sub-bolts 212. The cross-sections of the first upper recessed portion 2031 and the first lower recessed portion 2042 both match the cross-sectional shape of the first pressing block 208, which is also approximately a petal structure. The first pressing block 208 is embedded in the first upper recessed portion 2031 and the first lower recessed portion 2042. The first pressing block 208 can be circumferentially fixed by the special-shaped arc surface to prevent it from rotating.

[0056] In some examples, such as Figure 6 As shown, the outer peripheral portion of the top surface of the middle plate 204 is recessed to form a plurality of second lower recessed portions 2043, and the outer peripheral portion of the bottom surface of the top plate 203 is recessed to form a plurality of second upper recessed portions 2032, and the plurality of second upper recessed portions 2032 correspond to the plurality of second lower recessed portions 2043 one by one, and a second pressing block 213 is embedded between each second upper recessed portion 2032 and the corresponding second lower recessed portion 2043, and a second upper sealing block 213 is embedded between each second pressing block 213 and the top plate 203. A second lower sealing member 215 is embedded between each second pressing block 213 and the middle plate 204, and the top plate 203, the second pressing block 213 and the middle plate 204 are fixed by second bolts 216, and the top plate 203 and the middle plate 204 are limited and clamped from the outer part to avoid air leakage after the top plate 203 swells, resulting in failure of the crimping, and the second bolts 216 are screwed in from bottom to top, and the base 205 is provided with a second avoidance hole for avoiding the nut of the second bolt 216.

[0057] In some examples, such as Figure 4 , Figure 6 and Fig.12 As shown, the plurality of pressure-applying assemblies 1 are divided into at least two groups, namely a first pressure-applying assembly and a second pressure-applying assembly located outside the first pressure-applying assembly, wherein the first pressure-applying assembly comprises a plurality of first pistons 101a and first pressure rods 102a corresponding to the first pistons 101a, and the second pressure-applying assembly comprises a plurality of second pistons 101b and second pressure rods 102b corresponding to the second pistons 101b;

[0058] The piston hole 201 includes a plurality of first piston holes 201a for installing the first piston 101a and a plurality of second piston holes 201b for installing the second piston 101b. The air cavity 202 includes a first air cavity 202a connected with the plurality of first piston holes 201a and a second air cavity 202b connected with the plurality of second piston holes 201b and isolated from the first air cavity 202a. The gas enters the first piston hole 201a and the second piston hole 201b through the first air cavity 202a and the second air cavity 202b respectively to push the first piston 101a and the second piston 101b to move downward. The first piston 101a drives the first pressure rod 102a to move downward, and the second piston 101b drives the second pressure rod 102b to move downward, thereby forming two different pressures to meet different crimping requirements. Of course, a third pressure component can also be provided to form a third pressure.

[0059] In some examples, such as Fig.10 and Fig.11As shown, a third seal 217 and a fourth seal 218 arranged around the third seal 217 are pressed between the middle plate 204 and the top plate 203. The third seal 217 and the fourth seal 218 can be but are not limited to O-rings. The pressure plate 206 includes a first pressure plate 206a and a second pressure plate 206b arranged around the first pressure plate 206a. The outer peripheral wall of the first pressure plate 206a is recessed to form a first notch for installing the second pressure block 213, and the inner peripheral wall of the second pressure plate 206b is recessed to form a second notch for installing the second pressure block 213.

[0060] The inner circumferential wall of the third seal 217, the outer circumferential wall of the first upper seal 209, the outer circumferential wall of the second upper seal 214, the bottom surface of the top plate 203 and the top surface of the first pressure plate 206a together form the above-mentioned first air cavity 202a, and the outer circumferential wall of the third seal 217, the inner circumferential wall of the fourth seal 218, the bottom surface of the top plate 203 and the top surface of the second pressure plate 206b together form the above-mentioned second air cavity 202b.

[0061] In some examples, such as Figure 3 and Figure 5 As shown, the cross-sectional area of ​​the force transmission plane 3031 is larger than the cross-sectional area of ​​the buffer plate 304 so that the force transmission plate 303 and the buffer plate 304 are completely fitted together, and a step surface 3033 is formed between the force transmission plane 3031 and the avoidance slope 3032 .

[0062] In some examples, such as Figure 3 and Figure 5 As shown, there are a plurality of pressure rods 102 in the same pressure assembly 1, and the plurality of pressure rods 102 are distributed up and down and the top of each pressure rod 102 is configured as an upward convex arc surface, which can reduce the contact area between the pressure rods 102 or between the pressure rod 102 and the piston 101, reduce heat transfer, and avoid high temperature damage to the piston seal 207, resulting in seal failure;

[0063] like Fig.11As shown, the base 205 includes a first insulation board 2051 with a first lower protrusion 2051a, a second insulation board 2052 with a second lower protrusion 2052a and a connecting plate 2053 connected therebetween. The first insulation board 2051 and the second insulation board 2052 are both made of materials with low thermal conductivity. The first lower protrusion 2051a is located at a corner of the first insulation board 2051, and the second lower protrusion 2052a is located at a corner of the second insulation board 2052. A first insulation cavity 2054 is formed between the bottom surface of the first insulation board 2051 and the top surface of the connecting plate 2053, and a second insulation cavity 2055 is formed between the bottom surface of the second insulation board 2052 and the top surface of the force transmission plate 303. The first insulation cavity 2054 and the second insulation cavity 2055 can isolate the heat transferred from the heating plate 302 to avoid high temperature damage to the piston seal 207, resulting in sealing failure.

[0064] like Figure 8 As shown, a connecting rod 219 is provided between the base 205 and the heating plate 302, the pressure head assembly 3 is hung below the pressure assembly 1 through the connecting rod 219, a connecting block 220 is fixed on the top of the connecting rod 219, the cross-sectional area of ​​the connecting block 220 is larger than the cross-sectional area of ​​the connecting rod 219, and the first heat insulation board 2051 is provided with a connecting groove 2051b for limiting the connecting block 220 therein;

[0065] like Figure 7 and Fig. 9 As shown, the coating device also includes a membrane separation assembly 4, which includes a separation rod 401 slidably connected to the base 205 and passing downwardly out of the base 205, an elastic member 402 sleeved on the outside of the separation rod 401 and used to drive the separation rod 401 to move downward, and a separation ring 403 fixed to the bottom of the separation rod 401 and used to press the carrier for placing the chip to separate the pressure head assembly 3 from the chip, and the pressure head assembly 3 is located on the inner side of the separation ring 403.

[0066] Working principle:

[0067] The compressed air enters the piston hole 201 through the air cavity 202 to push the piston 101 in the piston hole 201 downward, and the piston 101 pushes the corresponding pressure rod 102 downward. The pressure rod 102 abuts against the force transmission plate 303 to transmit the pressure applied by the piston 101 to the force transmission plate 303. The force transmission plate 303 transmits the pressure from the pressure rod 102 evenly to the heating plate 302 through the buffer plate 304 with a certain elasticity, and then transmits it to the pressing plate 301, so that the pressing plate 301 applies uniform pressure to the wafer, and the avoidance slope 3032 of the force transmission plate 303 realizes that the thickness of the force transmission plate 303 gradually increases from the end to the center, which not only avoids the deformation of the force transmission plate 303 itself, but also meets the imprinting requirements of the workpiece.

[0068] The above-mentioned ideal embodiments of the present invention are for inspiration. Through the above-mentioned description, relevant staff can make various changes and modifications without departing from the technical idea of ​​the present invention. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A wafer coating device, characterized in that: include: A plurality of pressure-applying assemblies (1), each comprising a slidably arranged piston (101) and a corresponding pressure rod (102); An upper die base (2) for mounting the pressure assembly (1), the interior of which is provided with a plurality of piston holes (201) for mounting the pistons (101) and an air cavity (202) which is in communication with the plurality of piston holes (201) so as to drive the pistons (101) in the piston holes (201) to move downward when ventilation occurs; The pressure head assembly (3) comprises a pressure plate (301) for pressing down a wafer, a heating plate (302) fixed above the pressure plate (301) and used to heat the wafer, a force transmission plate (303) for receiving the pressure applied by the pressure application assembly (1), and a buffer plate (304) located between the force transmission plate (303) and the heating plate (302) and used to buffer the pressure applied to the force transmission plate (303), wherein the four are coaxially fixed and the buffer plate (304) is The cross-sectional area is smaller than the cross-sectional areas of the force transmission plate (303) and the heating plate (302); the bottom surface of the force transmission plate (303) comprises a force transmission plane (3031) located in the middle to fit with the buffer plate (304) and an avoidance slope (3032) located on the periphery of the force transmission plane (3031) to avoid the heating plate (302); and the avoidance slope (3032) gradually inclines upward from the force transmission plane (3031) to the avoidance slope (3032).

2. A wafer coating device according to claim 1, characterized in that: The upper die base (2) comprises a top plate (203), a middle plate (204) and a base (205) which are fixed in sequence from top to bottom, the top plate (203) and the middle plate (204) enclose the piston hole (201) and the air cavity (202), and the base (205) is provided with a slide groove for installing the pressure rod (102); The top surface of the middle plate (204) is concave to form a concave area (2041), a pressure plate (206) is embedded in the concave area (2041), and a piston seal (207) sleeved on the outside of the piston (101) is pressed between the pressure plate (206) and the middle plate (204).

3. A wafer coating device according to claim 2, characterized in that: The center portion of the top surface of the middle plate (204) is recessed to form a first lower recessed portion (2042), and the center portion of the bottom surface of the top plate (203) is recessed to form a first upper recessed portion (2031). A first pressing block (208) is embedded between the first upper recessed portion (2031) and the first lower recessed portion (2042). A first upper sealing member (209) is pressed between the first pressing block (208) and the top plate (203). A first lower sealing member (210) is pressed between the first pressing block (208) and the middle plate (204). The first pressing block (208) has a radially protruding abutting portion (2081) for abutting against the pressing plate (206). The top plate (203), the first pressing block (208) and the middle plate (204) are fixed by a first bolt.

4. A wafer coating device according to claim 3, characterized in that: The first bolt comprises a main bolt (211) located in the center and a plurality of sub-bolts (212) surrounding the main bolt (211); the main bolt (211) is screwed in from top to bottom, and the sub-bolts (212) are screwed in from bottom to top.

5. The wafer coating device according to claim 3, characterized in that: The cross section of the first pressing block (208) is a special-shaped arc surface formed by connecting a plurality of convex arc surfaces end to end, and the cross sections of the first upper recessed portion (2031) and the first lower recessed portion (2042) both match the cross-sectional shape of the first pressing block (208).

6. A wafer coating device according to claim 4, characterized in that: The peripheral portion of the top surface of the middle plate (204) is recessed to form a plurality of second lower recessed portions (2043), and the peripheral portion of the bottom surface of the top plate (203) is recessed to form a plurality of second upper recessed portions (2032). The plurality of second upper recessed portions (2032) correspond to the plurality of second lower recessed portions (2043) one by one, and a second pressing block (213) is embedded between each second upper recessed portion (2032) and the corresponding second lower recessed portion (2043). A second upper sealing member (214) is embedded between each second pressing block (213) and the top plate (203). A second lower sealing member (215) is embedded between each second pressing block (213) and the middle plate (204). The top plate (203), the second pressing blocks (213) and the middle plate (204) are fixed by second bolts (216).

7. A wafer coating device according to claim 6, characterized in that: The plurality of pressure-applying assemblies (1) are divided into at least two groups, namely a first pressure-applying assembly and a second pressure-applying assembly located outside the first pressure-applying assembly, wherein the first pressure-applying assembly comprises a plurality of first pistons (101a) and first pressure rods (102a) corresponding to the first pistons (101a), and the second pressure-applying assembly comprises a plurality of second pistons (101b) and second pressure rods (102b) corresponding to the second pistons (101b); The piston hole (201) comprises a plurality of first piston holes (201a) for installing a first piston (101a) and a second piston hole (201b) for installing a plurality of second pistons (101b), and the air cavity (202) comprises a first air cavity (202a) connected to the plurality of first piston holes (201a) and a second air cavity (202b) connected to the plurality of second piston holes (201b) and isolated from the first air cavity (202a).

8. A wafer coating device according to claim 7, characterized in that: A third sealing member (217) and a fourth sealing member (218) arranged around the third sealing member (217) are pressed between the middle plate (204) and the top plate (203); the pressing plate (206) comprises a first pressing plate (206a) and a second pressing plate (206b) arranged around the first pressing plate (206a); the inner peripheral wall of the third sealing member (217), the outer peripheral wall of the first upper sealing member (209), the outer peripheral wall of the second upper sealing member (214), the bottom surface of the top plate (203) and the top surface of the first pressing plate (206a) together form the above-mentioned first air cavity (202a); the outer peripheral wall of the third sealing member (217), the inner peripheral wall of the fourth sealing member (218), the bottom surface of the top plate (203) and the top surface of the second pressing plate (206b) together form the above-mentioned second air cavity (202b).

9. The wafer coating device according to claim 1, characterized in that: The cross-sectional area of ​​the force transmission plane (3031) is greater than the cross-sectional area of ​​the buffer plate (304), and a step surface (3033) is formed between the force transmission plane (3031) and the avoidance slope (3032).

10. The wafer coating device according to claim 2, characterized in that: There are a plurality of pressure rods (102) in a same pressure-applying assembly (1), the plurality of pressure rods (102) are distributed vertically, and the top of each pressure rod (102) is configured as an upwardly convex arc surface; The base (205) comprises a first heat insulation board (2051) having a first lower protrusion (2051a), a second heat insulation board (2052) having a second lower protrusion (2052a), and a connecting plate (2053) connected therebetween; a first heat insulation cavity (2054) is formed between the bottom surface of the first heat insulation board (2051) and the top surface of the connecting plate (2053); and a second heat insulation cavity (2055) is formed between the bottom surface of the second heat insulation board (2052) and the top surface of the force transmission plate (303).

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