Film-lamination apparatus for chip

Abstract

The present invention belongs to the technical field of semiconductor packaging and specifically relates to a film-lamination apparatus for a chip. The apparatus comprises pressure application assemblies, an upper die base, and a pressing head assembly; the pressing head assembly comprises a pressing plate used for pressing down on a chip, a heating plate fixed above the pressing plate and used for heating the chip, a force transmission plate used for bearing the pressure applied by the pressure application assemblies, and a buffer plate located between the force transmission plate and the heating plate and used for buffering the pressure borne by the force transmission plate. The four plates are coaxially fixed, the cross-sectional area of the buffer plate is less than the cross-sectional areas of the force transmission plate and the heating plate, and the bottom surface of the force transmission plate comprises a force transmission plane located at the center and a clearance inclined surface located on the periphery of the force transmission plane so as to provide clearance for the heating plate. In the present invention, the buffer plate is used to uniformly transmit to the pressing plate the pressure from the pressure application assemblies so that pressure is uniformly applied on a chip, thereby achieving uniform film lamination; the clearance inclined surface of the force transmission plate implements a gradual increase, from the ends to the center, in the thickness of the force transmission plate, which not only prevents the deformation of the force transmission plate itself, but also satisfies imprint requirements for a workpiece.

Description

Wafer film coating device TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor packaging, and particularly relates to a wafer film coating device. BACKGROUND

[0002] In the semiconductor manufacturing process, a thin film needs to be formed on a semiconductor wafer, and film thickness unevenness is easily caused in the film forming process, which reduces the yield of circuit elements. The problem of film thickness unevenness of the thin film is due to the uneven temperature and pressure generated on the wafer surface when the wafer is heated. Therefore, it is an important problem to keep the wafer surface temperature and pressure uniform during the film forming process. SUMMARY

[0003] The present application solves the technical problem that the semiconductor wafer in the prior art is prone to cause film thickness unevenness in the film forming process, which reduces the yield of circuit elements. The present application provides a wafer film coating device.

[0004] The technical solution adopted by the present application to solve the technical problem is: a wafer film coating device, comprising: a pressing assembly having a plurality of, each comprising a slidingly arranged piston and a corresponding pressure rod; an upper die seat for mounting the pressing assembly, having a plurality of piston holes for mounting the pistons and a gas cavity in communication with the plurality of piston holes to drive the pistons in the piston holes to move downward when the gas cavity is ventilated; and a pressure head assembly, comprising a pressure plate for pressing the wafer, a heating plate fixed above the pressure plate for heating the wafer, a force transmission plate for receiving the pressure applied by the pressing assembly, and a buffer plate located between the force transmission plate and the heating plate for buffering the pressure received by 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 comprises a force transmission plane located in the middle to fit the buffer plate and an avoidance inclined surface located on the periphery of the force transmission plane to avoid the heating plate, and the avoidance inclined surface gradually inclines upward from the force transmission plane to the direction of the avoidance inclined surface.

[0005] Further, the upper die seat comprises a top plate, an intermediate plate and a base fixed in order from top to bottom, the top plate and the intermediate plate form the above-mentioned piston hole and gas cavity, and the base is provided with a sliding groove for mounting the pressure rod; the top surface of the intermediate plate is recessed to form a recessed area, and a pressure plate is embedded in the recessed area, and a piston seal sleeve provided outside the piston is pressed between the pressure plate and the intermediate plate.

[0006] Further, a first lower recess is formed in a central part of a top surface of the intermediate plate, a first upper recess is formed in a bottom surface of the top plate, and a first pressing block is embedded between the first upper recess and the first lower recess.

[0007] Further, the first bolt includes a main bolt located at the center and a plurality of sub-bolts surrounding the main bolt, the main bolt is screwed from top to bottom, and the sub-bolt is screwed from bottom to top.

[0008] Further, a cross section of the first pressing block is a special-shaped arc surface formed by a plurality of outer convex arc surfaces connected in a head-to-tail manner, and cross sections of the first upper recess and the first lower recess are matched with the cross section shape of the first pressing block.

[0009] Further, a plurality of second lower recesses are formed in a peripheral part of the top surface of the intermediate plate, a plurality of second lower recesses are formed in a peripheral part of the bottom surface of the top plate, a plurality of second upper recesses correspond to the plurality of second lower recesses one by one, and a second pressing block is embedded between each second upper recess and the second lower recess corresponding thereto, a second upper sealing member is embedded between each second pressing block and the top plate, and a second lower sealing member is embedded between each second pressing block and the intermediate plate, and the top plate, the second pressing block, and the intermediate plate are fixed by a second bolt.

[0010] Further, the plurality of pressing assemblies are divided into at least two groups, which are a first pressing assembly and a second pressing assembly located at the periphery of the first pressing assembly, the first pressing assembly includes a plurality of first pistons and first pressing rods corresponding to the first pistons, and the second pressing assembly includes a plurality of second pistons and second pressing rods corresponding to the second pistons; the piston hole includes a plurality of first piston holes for mounting the first pistons and a plurality of second piston holes for mounting the second pistons, and the air cavity includes a first air cavity communicating with the plurality of first piston holes and a second air cavity communicating with the plurality of second piston holes and separated from the first air cavity.

[0011] Further, a third sealing member and a fourth sealing member surrounding the third sealing member are embedded between the intermediate plate and the top plate, the pressing plate includes a first pressing plate and a second pressing plate surrounding the first pressing plate, an inner peripheral wall of the third sealing member, an outer peripheral wall of the first upper sealing member, an outer peripheral wall of the second upper sealing member, a bottom surface of the top plate, and a top surface of the first pressing plate form the first air cavity, and an outer peripheral wall of the third sealing member, an inner peripheral wall of the fourth sealing member, a bottom surface of the top plate, and a top surface of the second pressing plate form the second air cavity.

[0012] Further, the cross-sectional area of the force transmission plane is larger than the cross-sectional area of the buffer plate, and a stepped surface is formed between the force transmission plane and the avoidance inclined surface.

[0013] Further, the same pressure applying assembly has a plurality of pressure rods, the plurality of pressure rods are distributed in an up-down manner, and the top of each pressure rod is provided as an upper convex arc surface; the base comprises a first heat insulation plate with a first lower convex portion, a second heat insulation plate with a second lower convex portion, and a connecting plate connected between the first heat insulation plate and the second heat insulation plate, a first heat insulation cavity is formed between the bottom surface of the first heat insulation plate and the top surface of the connecting plate, and a second heat insulation cavity is formed between the bottom surface of the second heat insulation plate and the top surface of the force transmission plate.

[0014] The application has the advantages that the pressure from the pressure applying assembly is uniformly transmitted to the pressing plate by the buffer plate to uniformly press the wafer, so that uniform film coating is achieved, and the avoidance inclined surface of the force transmission plate gradually increases the thickness of the force transmission plate from the end to the center, which avoids deformation of the force transmission plate itself and meets the requirements of the workpiece.

[0015] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0016] The application will be further described below in conjunction with the drawings and examples.

[0017] Fig. 1 is a three-dimensional structure diagram of the application; Fig. 2 is a top view of the application; Fig. 3 is a sectional view in the direction of A-A in Fig. 2; Fig. 4 is a partial enlarged view of part E in Fig. 3; Fig. 5 is a sectional view in the direction of B-B in Fig. 2; Fig. 6 is a partial enlarged view of part F in Fig. 5; Fig. 7 is a bottom view of the application; Fig. 8 is a sectional view in the direction of C-C in Fig. 7; Fig. 9 is a sectional view in the direction of D-D in Fig. 7; Fig. 10 is a top view of the application after removing the top plate; Fig. 11 is a three-dimensional structure diagram of the application after removing the top plate; Fig. 12 is a bottom view of the top plate in the application; Fig. 13 is a three-dimensional structure diagram of the first pressing block in the application; Fig. 14 is a pressing diagram without a buffer plate; and Fig. 15 is a pressing diagram with a buffer plate.

[0018] In the figure: 1, pressure assembly; 101, piston; 101a, first piston; 101b, second piston; 102, pressure rod; 102a, first pressure rod; 102b, second pressure rod; 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, middle plate; 2041, recess area; 2042, first lower recess; 2043, second lower recess; 205, base; 2051, first heat insulation plate; 2051a, first lower protrusion; 2051b, connecting groove; 2052, second heat insulation plate; 2052a, second lower protrusion; 2053, connecting plate; 2054, first heat insulation cavity; 2055, second heat insulation cavity; 206, pressure plate; 206a, first pressure plate; 206b, second pressure plate; 207, piston sealing element; 208, first pressure block; 2081, abutting portion; 209, first upper sealing element; 210, first lower sealing element; 211, main bolt; 212, sub-bolt; 213, second pressure block; 214, second upper sealing element; 215, second lower sealing element; 216, second bolt; 217, third sealing element; 218, fourth sealing element; 219, connecting rod; 220, connecting block; 3, pressure head assembly; 301, pressure plate; 302, heating plate; 303, force transmission plate; 3031, force transmission plane; 3032, avoidance inclined surface; 3033, step surface; 304, buffer plate; 4, membrane separation assembly; 401, separation rod; 402, elastic element; 403, separation ring. DETAILED DESCRIPTION

[0019] The application will now be described in further detail with reference to the drawings. These drawings show only the essential features of the application and are not to scale. The drawings are schematic representations only of the basic structure of the application and therefore only show those features relevant to the present application. Directions and references (e.g. upper, lower, left, right, etc.) can be used only to aid in the description of features in the drawings. The following detailed description is therefore not to be taken in a limiting sense and the scope of the claimed subject matter is defined only by the claims and their equivalents.

[0020] As shown in FIG. 1 and FIG. 2, a wafer film coating device comprises: a pressing assembly 1, having a plurality of pistons 101 and corresponding pressure rods 102; an upper die seat 2 for mounting the pressing assembly 1, having a plurality of piston holes 201 for mounting the pistons 101 and a plurality of air cavities 202 for driving the pistons 101 in the piston holes 201 to move downward when air is supplied; the plurality of pistons 101 correspond to the plurality of piston holes 201 one by one, and each piston 101 is slidably mounted in the corresponding piston hole 201; air is supplied into the plurality of piston holes 201 through the air cavities 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, as shown in FIG. 3 and FIG. 5; and a pressure head assembly 3, comprising a pressing plate 301 for pressing the wafer, a heating plate 302 fixed above the pressing plate 301 for heating the wafer, a force transmission plate 303 for bearing the pressure applied by the pressing assembly 1, and a buffer plate 304 between the force transmission plate 303 and the heating plate 302 for buffering the pressure applied to 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 center screw inserted in the center position, which avoids the deviation between the components and saves the installation time, and the heating plate 302 and the pressing plate 301 are fixed by edge screws located at the edges, as shown in FIG. 3 and FIG. 5.

[0021] The heating plate 302 is provided with a heating element, and the heat generated by the heating element is transmitted to the wafer through the heating plate 302 and the pressing plate 301 to meet the heating requirements of the wafer; the plurality of pressure rods 102 are arranged above the force transmission plate 303 to transmit the pressure applied by the pistons 101 to the force transmission plate 303; the cross-sectional area of the buffer plate 304 is smaller than that of the force transmission plate 303 and the heating plate 302, i.e. the buffer plate 304 is located in the inner periphery of the force transmission plate 303, forming a similar I-shaped structure, the buffer plate 304 has a certain elasticity and a high-temperature-resistant and heat-insulating property, and is preferably made of PTFE material, which has a larger thermal expansion coefficient to alleviate the thermal stress received from the heating plate 302, and the elastic property of the buffer plate 304 can uniformly transmit the pressure from the pressure rods 102 to the heating plate 302, and then to the pressing plate 301, playing a role of intermediate transition, as shown in FIG. 14 and FIG. 15, 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 that in the central area, and the pressure is very uneven, while when the buffer plate 304 is provided, the pressure in the peripheral area and the central area is balanced.

[0022] The bottom surface of the force transmission plate 303 includes a force transmission plane 3031 located in the middle to be attached to the buffer plate 304 and an avoidance inclined surface 3032 located at the periphery of the force transmission plane 3031 to avoid the heating plate 302, and the avoidance inclined surface 3032 gradually inclines upward from the force transmission plane 3031 to the direction of the avoidance inclined surface 3032, that is, the thickness of the force transmission plate 303 gradually increases from the end to the center. The pressure transmitted by the force transmission plate 303 to the buffer plate 304 needs to be kept within a constant range, and too large pressure will cause damage to the workpiece, and too small pressure will cause incomplete stamping of the workpiece. If a relatively thin regular disc-shaped force transmission plate 303 is used, the stress applied to the buffer plate 304 is small, which cannot meet the stamping requirements of the workpiece, and the force transmission plate 303 is easily bent too much due to different materials, so that the end of the force transmission plate 303 is closer to the heating plate 302. Using a relatively thick force transmission plate 303 will increase the cost. The present application gradually increases the thickness of the force transmission plate 303 from the end to the center by using the avoidance inclined surface 3032, which maximally avoids the deformation of the force transmission plate 303 itself and meets the stamping requirements of the workpiece.

[0023] In some examples, as shown in FIGS. 3 and 5, the upper die seat 2 includes a top plate 203, an intermediate plate 204 and a base 205 fixed in sequence from top to bottom, the top plate 203 and the intermediate plate 204 form the piston hole 201 and the air cavity 202, and the base 205 is provided with a sliding groove for mounting the pressure rod 102; as shown in FIG. 4, the top surface of the intermediate plate 204 is recessed to form a recessed area 2041, and the recessed area 2041 is embedded with a pressing plate 206, and the piston seal 207 externally sleeved on the piston 101 is pressed between the pressing plate 206 and the intermediate plate 204. The pressing plate 206 can press multiple piston seals 207 at the same time, improving the assembly efficiency.

[0024] In some examples, as shown in FIG. 4, the center part of the top surface of the intermediate plate 204 is recessed to form a first lower recessed part 2042, and the center part of the bottom surface of the top plate 203 is recessed to form a first upper recessed part 2031, and the first upper recessed part 2031 and the first lower recessed part 2042 are embedded with a first pressing block 208, the first pressing block 208 is pressed between the top plate 203 and the first upper seal 209, and the first pressing block 208 is pressed between the intermediate plate 204 and the first lower seal 210. The first upper seal 209 and the first lower seal 210 can separate the air cavity 202 from the first upper recessed part 2031 and the first lower recessed part 2042 to ensure the air tightness of the air cavity 202; the first pressing block 208 protrudes radially to form an abutting portion 2081 for abutting against the pressing plate 206, and the abutting portion 2081 can press the pressing plate 206 tightly, and the top plate 203, the first pressing block 208 and the intermediate plate 204 are fixed by first bolts to limit and clamp the top plate 203 and the intermediate plate 204 from the center part, avoiding the top plate 203 from swelling to cause air leakage and resulting in poor pressing.

[0025] In some examples, as shown in FIG. 4, the first bolt includes a central main bolt 211 and a plurality of sub-bolts 212 surrounding the main bolt 211, the nominal diameter of the main bolt 211 is larger than that of the sub-bolts 212, the main bolt 211 is screwed from top to bottom, the top plate 203 is provided with a counterbore for accommodating the nut of the main bolt 211, the sub-bolts 212 are screwed from bottom to top, the base 205 is provided with a first avoiding hole for avoiding the nut of the sub-bolt 212, and the main bolt 211 and the sub-bolt 212 are screwed from different directions, which can improve the connection strength of the top plate 203 and the middle plate 204.

[0026] In some examples, as shown in FIG. 13, the first pressing block 208 has a cross section in the shape of a petal formed by a plurality of outer convex arc surfaces connected end to end, and the number of the outer convex arc surfaces corresponds to the number of the sub-bolts 212, the cross sections of the first upper recessed part 2031 and the first lower recessed part 2042 are matched with the cross section shape of the first pressing block 208, and are also approximately in the shape of a petal, the first pressing block 208 is embedded in the first upper recessed part 2031 and the first lower recessed part 2042, and the first pressing block 208 is fixed in the circumferential direction by the arc surfaces to prevent rotation.

[0027] In some examples, as shown in FIG. 6, the peripheral part of the top surface of the middle plate 204 is recessed to form a plurality of second lower recessed parts 2043, the peripheral part of the bottom surface of the top plate 203 is recessed to form a plurality of second upper recessed parts 2032, the second upper recessed parts 2032 and the second lower recessed parts 2043 correspond to each other one by one, and each second upper recessed part 2032 and the corresponding second lower recessed part 2043 are embedded with a second pressing block 213, each second pressing block 213 and the top plate 203 are embedded with a second upper sealing member 214, and each second pressing block 213 and the middle plate 204 are embedded with a second lower sealing member 215, the top plate 203, the second pressing block 213 and the middle plate 204 are fixed by a second bolt 216, the top plate 203 and the middle plate 204 are clamped and fixed from the peripheral part, which can prevent the top plate 203 from swelling and causing air leakage, resulting in compression failure, and the second bolt 216 is screwed from bottom to top, and the base 205 is provided with a second avoiding hole for avoiding the nut of the second bolt 216.

[0028] In some examples, as shown in FIG. 4, FIG. 6 and FIG. 12, the plurality of pressing assemblies 1 are divided into at least two groups, i.e. a first pressing assembly and a second pressing assembly located at the periphery of the first pressing assembly, the first pressing assembly comprises a plurality of first pistons 101a and first pressure rods 102a corresponding to the first pistons 101a, and the second pressing 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 mounting the first pistons 101a and a plurality of second piston holes 201b for mounting the second pistons 101b, and the gas cavity 202 comprises a first gas cavity 202a in communication with the plurality of first piston holes 201a and a second gas cavity 202b in communication with the plurality of second piston holes 201b and separated from the first gas cavity 202a; gas enters the first piston holes 201a and the second piston holes 201b through the first gas cavity 202a and the second gas cavity 202b respectively to push the first pistons 101a and the second pistons 101b to move downward, the first pistons 101a drive the first pressure rods 102a to move downward, and the second pistons 101b drive the second pressure rods 102b to move downward, thereby forming two different pressures to meet different pressing requirements. Of course, a third pressing assembly can also be provided to form a third pressure.

[0029] In some examples, as shown in FIG. 10 and FIG. 11, a third sealing member 217 is arranged between the intermediate plate 204 and the top plate 203, and a fourth sealing member 218 is arranged around the third sealing member 217, the third sealing member 217 and the fourth sealing member 218 can be but are not limited to O-shaped sealing rings, the pressing plate 206 comprises a first pressing plate 206a and a second pressing plate 206b arranged around the first pressing plate 206a, and the outer peripheral wall of the first pressing plate 206a is recessed to form a first notch for mounting the second pressing block 213, and the inner peripheral wall of the second pressing plate 206b is recessed to form a second notch for mounting the second pressing block 213.

[0030] 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 form the first gas cavity 202a, and 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 form the second gas cavity 202b.

[0031] In some examples, as shown in FIG. 3 and FIG. 5, the cross-sectional area of the force transmission plane 3031 is greater than the cross-sectional area of the buffer plate 304 so that the force transmission plate 303 and the buffer plate 304 are completely attached, and a stepped surface 3033 is formed between the force transmission plane 3031 and the avoidance inclined surface 3032.

[0032] In some examples, as shown in FIG. 3 and FIG. 5, the same pressure assembly 1 has several pressure rods 102, and the several pressure rods 102 are arranged in an up-down distribution, and the top of each pressure rod 102 is provided as an upper 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 the heat transfer, avoid high-temperature damage to the piston seal 207, and cause sealing failure; as shown in FIG. 11, the base 205 includes a first heat insulation plate 2051 having a first lower convex portion 2051a, a second heat insulation plate 2052 having a second lower convex portion 2052a, and a connecting plate 2053 connected between the two, the first heat insulation plate 2051 and the second heat insulation plate 2052 are both made of a material with a low thermal conductivity, the first lower convex portion 2051a is located at the corner portion of the first heat insulation plate 2051, the second lower convex portion 2052a is located at the corner portion of the second heat insulation plate 2052, a first heat insulation cavity 2054 is formed between the bottom surface of the first heat insulation plate 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 plate 2052 and the top surface of the force transmission plate 303, the first heat insulation cavity 2054 and the second heat insulation cavity 2055 can isolate the heat transferred from the heating plate 302, avoid high-temperature damage to the piston seal 207, and cause sealing failure.

[0033] As shown in FIG. 8, 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, the connecting rod 219 is fixed with a connecting block 220 at the top, the cross-sectional area of the connecting block 220 is greater than that of the connecting rod 219, and the first heat insulation plate 2051 is provided with a connecting groove 2051b for limiting the connecting block 220 inside; as shown in FIG. 7 and FIG. 9, the film separating assembly 4 includes a separating rod 401 slidably connected with the base 205 and downwardly penetrating the base 205, an elastic member 402 sleeved outside the separating rod 401 and used for driving the separating rod 401 to move downward, and a separating ring 403 fixed at the bottom of the separating rod 401 and used for pressing a carrier for placing a wafer to separate the pressure head assembly 3 from the wafer, and the pressure head assembly 3 is located inside the separating ring 403.

[0034] Working principle: compressed air enters the piston hole 201 through the air cavity 202 to push the piston 101 in the piston hole 201 to move downward, the piston 101 pushes the corresponding pressure rod 102 to move 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 to the heating plate 302 through the buffer plate 304 with certain elasticity, and then transmits the pressure to the pressing plate 301, so that the pressing plate 301 uniformly presses the wafer, and the avoiding 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 requirements of the workpiece stamping.

[0035] The above-mentioned ideal embodiments according to the application are for illustration, and through the above-mentioned description, relevant personnel can make various changes and modifications without deviating from the technical idea of the application. The technical scope of the application is not limited to the content in the specification, and must be determined according to the scope of claims.

Claims

1. A wafer film coating apparatus, characterized by: The utility model relates to a wafer pressing device, which comprises: a pressing assembly (1) having a plurality of pistons (101) and corresponding pressure rods (102) arranged in sliding mode; an upper die seat (2) for mounting the pressing assembly (1), which is internally provided with a plurality of piston holes (201) for mounting the pistons (101) and air cavities (202) in communication with the plurality of piston holes (201) to drive the pistons (101) in the piston holes (201) to move downward when ventilated; and a pressure head assembly (3) comprising a pressing plate (301) for pressing the wafer, a heating plate (302) fixed above the pressing plate (301) and used for heating the wafer, a force transmission plate (303) for bearing the pressure applied by the pressing 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 borne by the force transmission plate (303), the four being coaxially fixed and the cross-sectional area of the buffer plate (304) being smaller than that of the force transmission plate (303) and the heating plate (302), the bottom surface of the force transmission plate (303) comprising a force transmission plane (3031) located in the middle part to be in contact with the buffer plate (304) and a avoiding inclined surface (3032) located at the periphery of the force transmission plane (3031) to avoid the heating plate (302), and the avoiding inclined surface (3032) gradually inclines upward from the force transmission plane (3031) to the avoiding inclined surface (3032).

2. The wafer film coating apparatus according to claim 1, wherein: The upper die seat (2) comprises a top plate (203), an intermediate plate (204) and a base (205) fixed in sequence from top to bottom, the top plate (203) and the intermediate plate (204) form the above-mentioned piston holes (201) and air cavities (202), and the base (205) is provided with a sliding groove for mounting the pressure rod (102). The top surface of the intermediate plate (204) is recessed to form a recessed area (2041), and the recessed area (2041) is embedded with a pressing plate (206), and a piston seal (207) externally sleeved on the piston (101) is pressed between the pressing plate (206) and the intermediate plate (204).

3. The wafer film coating apparatus of claim 2, wherein: The central part of the top surface of the intermediate plate (204) is recessed to form a first lower recessed part (2042), the central part of the bottom surface of the top plate (203) is recessed to form a first upper recessed part (2031), the first upper recessed part (2031) and the first lower recessed part (2042) are embedded with a first pressing block (208), the first pressing block (208) is pressed between the top plate (203) and the first upper seal (209), the first pressing block (208) is pressed between the intermediate plate (204) and the first lower seal (210), and the first pressing block (208) is radially protruded with an abutting part (2081) for abutting with the pressing plate (206), and the top plate (203), the first pressing block (208) and the intermediate plate (204) are fixed by a first bolt.

4. The wafer film coating apparatus of claim 3, wherein: 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 from top to bottom, and the sub-bolts (212) are screwed from bottom to top.

5. The wafer film coating apparatus of claim 3, wherein: The first pressing block (208) has a cross section in the shape of a special arc surface formed by a plurality of arc surfaces connected end to end, and the cross sections of the first upper recess (2031) and the first lower recess (2042) are matched with the cross section shape of the first pressing block (208).

6. The wafer film coating apparatus of claim 4, wherein: The top surface of the intermediate plate (204) is recessed at the peripheral part to form a plurality of second lower recesses (2043), and the bottom surface of the top plate (203) is recessed at the peripheral part to form a plurality of second upper recesses (2032), the second upper recesses (2032) correspond to the second lower recesses (2043) one by one, and each second upper recess (2032) and the corresponding second lower recess (2043) are embedded with a second pressing block (213), each second pressing block (213) and the top plate (203) are embedded with a second upper sealing element (214), each second pressing block (213) and the intermediate plate (204) are embedded with a second lower sealing element (215), and the top plate (203), the second pressing block (213) and the intermediate plate (204) are fixed by a second bolt (216).

7. The wafer film coating apparatus of claim 6, wherein: The plurality of pressing assemblies (1) are divided into at least two groups, which are a first pressing assembly and a second pressing assembly located at the periphery of the first pressing assembly, the first pressing assembly includes a plurality of first pistons (101a) and first pressing rods (102a) corresponding to the first pistons (101a), and the second pressing assembly includes a plurality of second pistons (101b) and second pressing rods (102b) corresponding to the second pistons (101b). The piston hole (201) includes a plurality of first piston holes (201a) for mounting the first pistons (101a) and a plurality of second piston holes (201b) for mounting the second pistons (101b), and the air cavity (202) includes a first air cavity (202a) in communication with the plurality of first piston holes (201a) and a second air cavity (202b) in communication with the plurality of second piston holes (201b) and separated from the first air cavity (202a).

8. The wafer film coating apparatus of claim 7, wherein: The third sealing element (217) and the fourth sealing element (218) surrounding the third sealing element (217) are arranged between the intermediate plate (204) and the top plate (203), the pressing plate (206) includes a first pressing plate (206a) and a second pressing plate (206b) surrounding the first pressing plate (206a), the inner circumferential wall of the third sealing element (217), the outer circumferential wall of the first upper sealing element (209), the outer circumferential wall of the second upper sealing element (214), the bottom surface of the top plate (203) and the top surface of the first pressing plate (206a) form the first air cavity (202a), and the outer circumferential wall of the third sealing element (217), the inner circumferential wall of the fourth sealing element (218), the bottom surface of the top plate (203) and the top surface of the second pressing plate (206b) form the second air cavity (202b).

9. The wafer film coating apparatus of claim 1, wherein: The cross-sectional area of the force transmission plane (3031) is greater than the cross-sectional area of the buffer plate (304), and a stepped surface (3033) is formed between the force transmission plane (3031) and the avoidance inclined surface (3032).

10. The wafer film coating apparatus of claim 1, wherein: The press rods (102) in the same pressure applying assembly (1) are several, and the several press rods (102) are distributed in up and down, and the top of each press rod (102) is provided as an upper convex arc surface; The base (205) comprises a first heat insulation plate (2051) with a first lower convex part (2051a), a second heat insulation plate (2052) with a second lower convex part (2052a) and a connecting plate (2053) connected between the two, a first heat insulation cavity (2054) is formed between the bottom surface of the first heat insulation plate (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 plate (2052) and the top surface of the force transmission plate (303).

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