Wafer clamping device

Abstract

The present invention provides a wafer clamping device. The wafer clamping device includes a base plate, a fixing unit, and an unlocking mechanism. The fixing units are arranged at least three times on the periphery of the base plate, supporting the wafer at a certain distance h from the base plate. The unlocking mechanism is provided on one side of the base plate, and an installation space for placing the wafer is provided on the other side. The unlocking mechanism moves relative to one end of the fixing unit, causing the other end of the fixing unit to move toward the installation space for clamping or away from the installation space for release. The present invention overcomes the influence of electrostatic attraction on the back of the wafer and provides a method for eliminating static electricity, thereby resolving the problem of difficulty in removing wafers such as lithium oxide wafers due to static electricity generated during the injection process.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a wafer clamping device. Background Art

[0002] Currently, wafer clamping methods typically include mechanical clamping and electrostatic clamping. Both clamping methods typically involve a physical structure on the back of the wafer in contact with the wafer. Mechanical clamping typically uses a water-cooled backplate, while electrostatic clamping typically uses a water-cooled backplate plus an insulating layer. Piezoelectric crystal materials such as lithium oxide, due to their unique piezoelectric properties and pyroelectric effect, often generate static electricity on the wafer surface during processing. This surface static electricity creates an attractive force between the wafer and the backplate, attracting the wafer to the backplate, making wafer removal difficult and even causing fragmentation. Both current clamping methods present the challenge of dissipating or eliminating static electricity on the wafer surface. Summary of the Invention

[0003] The object of the present invention is to provide a wafer clamping device that overcomes the influence of static electricity on wafer surface on wafer removal and reduces the influence of contact support on wafer temperature uniformity.

[0004] The technical solution of the present invention is: a chip clamping device includes a base plate, a fixing unit and an unlocking mechanism, at least three fixing units are arranged on the periphery of the base plate, the unlocking mechanism is provided on one side of the base plate, and an installation space for placing the chip is provided on the other side; the unlocking mechanism is displaced relative to one end of the fixing unit, so that the other end of the fixing unit moves closer to the installation space for clamping or away from the installation space for release.

[0005] In the above scheme, by designing an effective crystal clamping and support structure, the influence of static electricity on the chip surface on chip removal is overcome, and the influence of contact support on the temperature uniformity of the chip is reduced, which is conducive to eliminating the risk of debris during loading and unloading of the final injection process and improving the uniformity of the final injection process.

[0006] Preferably, a certain distance h is maintained between the wafer placed in the installation space and the substrate. The distance h is set so that the electrostatic force generated between the wafer surface static electricity and the substrate does not affect wafer removal.

[0007] Preferably, the fixing unit is provided with supporting fins for supporting the wafer.

[0008] Preferably, the displacement movement of the unlocking mechanism includes a horizontal displacement movement and a rotational movement that converts the horizontal displacement movement into a rotational movement acting on the fixing unit, so that the fixing unit is swung toward the installation space in an expanded manner through the rotational movement.

[0009] Preferably, the unlocking mechanism includes a parallel linkage mechanism and a driving ring for arranging the fixing units, the driving ring being arranged below the base plate, and the parallel linkage mechanism being hinged to the driving ring on a side away from the base plate; a radial end surface of the driving ring is provided with a slope corresponding to the number of fixing units, and the slope is arranged adjacent to the base plate;

[0010] When the parallel link mechanism moves in a horizontal displacement, it drives the driving ring to rotate, so as to drive the ramp to enter or leave the fixing unit.

[0011] Preferably, the base plate is a hollow annular plate.

[0012] Preferably, one corner of the parallel linkage mechanism is the power input end, and the other corner is provided with a return spring, and the return spring and the power input end are located at two diagonal corners of the parallel linkage mechanism.

[0013] Preferably, the thickness of the slope gradually increases in a clockwise direction along the circumference of the driving ring.

[0014] Preferably, the fixing unit includes a support assembly, a pressure hook assembly, a spring, a rotating shaft, a first bearing, and a second bearing; the support assembly is mounted on the base plate, the pressure hook assembly is arranged in the support assembly, and one end of the pressure hook assembly is hinged to the support assembly through the rotating shaft, and the other end extends out of the support assembly to extend toward the installation space; the spring connects the pressure hook assembly and the support assembly; the first bearing is arranged on the support assembly, and the second bearing is arranged on the pressure hook assembly; the second bearing and the first bearing are arranged opposite to each other up and down and form a support cavity for placing a driving ring therebetween; the spring and the second bearing are connected to two opposite sides of the pressure hook assembly;

[0015] When the driving ring rotates to cause the slope to open the support cavity, the pressing hook assembly swings in the direction away from the installation space; when the driving ring rotates in the opposite direction to restore the support cavity, the spring pulls the pressing hook assembly to swing in the direction close to the installation space.

[0016] Preferably, the pressing hook assembly includes a shaft block and a pressing hook block provided on the shaft block, the shaft block is hinged to the support assembly, and the upper end of the pressing hook block is provided with a structure inclined toward the installation space.

[0017] Preferably, the support assembly includes a support block, a connecting block, a support fin and a pressure block, the connecting block is a U-shaped structure with an opening, the support block is arranged at the opening, and one end of the support block is connected to the connecting block, and the other end is provided with a horizontally protruding pressure block for abutting the upper end surface of the substrate, and the upper end of the pressure block is provided with the supporting fin; the pressure hook assembly is arranged in the U-shaped cavity of the connecting block, and the upper end of the pressure hook assembly extends out of the support block on the side close to the supporting fin; the lower end of the pressure hook assembly is hinged to the connecting block; the spring connects the support block and the lower end of the pressure hook assembly respectively in the U-shaped cavity of the connecting block; the second bearing and the first bearing are on the same side as the pressure block.

[0018] Preferably, the supporting fins are inclined toward the installation space.

[0019] Preferably, the support block and the pressing block are made of any one of aluminum, ceramic, PEEK and PTFE.

[0020] Compared with related technologies, the beneficial effects of the present invention are: overcoming the influence of electrostatic attraction on the back of the chip, and providing a way to eliminate static electricity, solving the problem of difficulty in removing chips such as lithium oxide caused by static electricity during the injection process, and at the same time, through the innovative design of support structure and materials, reducing the influence of contact support on chip temperature uniformity, which is conducive to improving the uniformity of the final injection process. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the three-dimensional structure of the wafer clamping device provided by the present invention;

[0022] Figure 2 A schematic cross-sectional view of a wafer clamping device provided by the present invention;

[0023] Figure 3 for Figure 1 A structural diagram of a fixed unit from one perspective;

[0024] Figure 4 for Figure 1 A structural diagram of the fixed unit from another perspective;

[0025] Figure 5 for Figure 3 A schematic diagram of the structure of the support assembly in FIG.

[0026] Figure 6 for Figure 5 The right side diagram of

[0027] Figure 7 for Figure 2 A is an enlarged schematic diagram;

[0028] Figure 8 for Figure 3 A schematic structural diagram of the pressure hook assembly in FIG.

[0029] Figure 9 Schematic diagram of the surface temperature distribution of lithium lithium oxide wafers (wherein, a is a schematic diagram of the surface temperature distribution of the wafer obtained by using a pressure block and a pressure hook made of aluminum alloy material to clamp the wafer, and the supporting fin is an inclined surface; b is a schematic diagram of the surface temperature distribution of the wafer obtained by using a pressure block and a pressure hook made of PEEK material to clamp the wafer, and the supporting fin is an inclined surface; c is a schematic diagram of the surface temperature distribution of the wafer obtained by using a pressure block and a pressure hook made of PEEK material to clamp the wafer, and the supporting fin is a flat surface).

[0030] In the accompanying drawings: 1. Base plate; 2. Fixing unit; 3. Unlocking mechanism; 4. Wafer; 201. Support assembly; 202. Pressing hook assembly; 205. First bearing; 206. Second bearing; 20101. Support block; 20102. Connecting block; 20103. Support fin; 20104. Pressing block; 20105. Mounting hole; 20201. Pressing hook block; 20202. Rotating shaft block; 20201. Pressing hook block; 20202. Rotating shaft block; 301. Ramp; 302. Drive ring; 303. Parallel linkage mechanism; 304. Return spring; 305. Articulated shaft; 4. Wafer. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. It should be noted that the embodiments and features of the embodiments may be combined unless they conflict. For ease of description, the words "upper," "lower," "left," and "right" appear below merely to indicate the directions of upper, lower, left, and right in the accompanying drawings and do not limit the structure.

[0032] like Figure 1 As shown, a wafer clamping device provided in this embodiment includes a base plate 1 , a fixing unit 2 and an unlocking mechanism 3 .

[0033] like Figure 1 、 Figure 2 As shown, the substrate 1 is made of aluminum alloy and has a cavity that matches the size of the wafer 4, forming a hollow annular plate. The substrate 1 serves as the base of the wafer clamping device. Four fixing units 2 are arranged around the periphery of the substrate 1. One side of the substrate 1 is provided with the unlocking mechanism 3, and the other side is provided with an installation space for placing the wafer 4. The wafer 4 placed in the installation space is maintained at a certain distance h from the substrate 1. The fixing units 2 are used to support and compress the wafer 4. Specifically:

[0034] like Figure 3 、 Figure 4As shown, the fixing unit 2 includes a support assembly 201, a pressure hook assembly 202, a spring 203, a rotating shaft 204, a first bearing 205, and a second bearing 206. The support assembly 201 is mounted on the base plate 1, and the pressure hook assembly 202 is disposed within the support assembly 201. One end of the pressure hook assembly 202 is hinged to the support assembly 201 via the rotating shaft 204, and the other end extends out of the support assembly 201 and into the installation space. The spring 203 connects the pressure hook assembly 202 and the support assembly 201. The first bearing 205 is disposed on the support assembly 201, and the second bearing 206 is disposed on the pressure hook assembly 202. The second bearing 206 is positioned vertically opposite the first bearing 205, forming a support cavity therebetween for accommodating the drive ring 302. The spring 203 and the second bearing 206 are connected to opposite sides of the pressure hook assembly 202.

[0035] When the driving ring 302 rotates to cause the slope 301 to open the support cavity, the pressing hook assembly 202 swings in the direction away from the installation space; when the driving ring 302 rotates in the opposite direction to restore the support cavity, the spring 203 pulls the pressing hook assembly 202 to swing in the direction close to the installation space.

[0036] like Figure 5 、 Figure 6 The support assembly 201 includes a support block 20101, a connecting block 20102, a supporting fin 20103 and a pressing block 20104. The connecting block 20102 is a U-shaped structure with an opening. The support block 20101 is arranged at the opening, and one end of the support block 20101 is connected to the connecting block 20102. The other end is provided with a horizontally protruding pressing block 20104 for abutting against the upper end surface of the substrate 1. The upper end surface of the pressing block 20104 is provided with the supporting fin 20103. The supporting fin 20103 is inclined toward the installation space (i.e., as shown in FIG. 2 ). Figure 7 As shown, the supporting surface of the supporting fin 20103 is tilted at a certain angle θ) toward the wafer 4, which can reduce the contact area between the wafer 4 and the supporting fin 20103 and lower the thermal conductivity.

[0037] The pressure hook assembly 202 is arranged in the U-shaped cavity of the connecting block 20102, and the upper end of the pressure hook assembly 202 extends out of the support block 20101 on the side close to the support fin 20103. The side of the support block 20101 away from the pressure block 20104 is a through groove, which provides a swinging movement space for the part of the pressure hook assembly 202 (the pressure hook block) that fits in the through groove. The lower end of the pressure hook assembly 202 is hinged to the connecting block 20102. The spring 203 connects the lower ends of the support block 20101 and the pressure hook assembly 202 respectively in the U-shaped cavity of the connecting block 20102; the second bearing 206 and the first bearing 205 are on the same side as the pressure block 20104.

[0038] like Figure 8 As shown, the pressing hook assembly 202 includes a shaft block 20202 and a pressing hook block 20201 provided on the shaft block 20202. The shaft block 20202 and the pressing hook block 20201 are connected by bolts (as shown in FIG. Figure 4 The two small vertical bolts in the connecting block 20102 are shown. The rotating shaft block 20202 is hinged to the supporting assembly 201, and the upper end of the pressing hook block 20201 is provided with a structure inclined toward the installation space.

[0039] like Figure 1 、 Figure 2 As shown, the middle part of the wafer 4 is hollowed out. The fixing unit 2 is mounted on the substrate 1 by bolts, which extend radially into the substrate 1. Figure 5 As shown, the sidewall of the connecting block 20102 is provided with mounting holes 20105, which are provided with bolts for connection to the base plate 1. At this point, the lower end surface of the pressing block 20104 contacts the upper end surface of the base plate 1, and the upper end surface of the pressing block 20104 contacts the lower end surface of the wafer 4, thereby supporting the wafer 4. The lower end surface of the inclined structure at the upper end of the pressing hook block 20201 clamps the upper end surface of the wafer 4, forming a clamping structure. The mounting space is formed between the pressing block 20104 and the inclined structure at the upper end of the pressing hook block 20201. The four fixing units 2 are provided with the first bearing 205 and the second bearing 206 mounted on their sides facing each other.

[0040] The unlocking mechanism 3 comprises a parallel linkage 303 and a drive ring 302 that matches the outer shape of the base plate 1. The drive ring 302 is positioned below the base plate 1. The parallel linkage 303 is hingedly connected to the drive ring 302 on the side facing away from the base plate 1 via a hinge shaft 305. The radial end surface of the drive ring 302 is provided with ramps 301 corresponding in number to the number of fixing units 2, positioned adjacent to the base plate 1. The thickness of the ramps 301 gradually increases clockwise along the circumference of the drive ring 302.

[0041] One corner of the parallel linkage mechanism 303 is a power input end, and the other corner is provided with a return spring 304 . The return spring 304 and the power input end are located at two opposite corners of the parallel linkage mechanism 303 .

[0042] The force of the pressure hook assembly 202 to clamp the wafer 4 comes from the tension of the spring 203, and has a flexible, non-rigid clamping. The maximum clamping force on the wafer 4 can be controlled by properly selecting the spring 203 to reduce the risk of fragmentation.

[0043] The unlocking mechanism 3 moves relative to one end of the fixed unit 2, including horizontal displacement and rotational motion by converting the horizontal displacement into rotational motion acting on the fixed unit 2. Specifically, when a thrust is applied to the power input end of the parallel linkage 303, driving the parallel linkage 303 to move horizontally, the driving ring 302 rotates clockwise, causing the ramp 301 to enter the support cavity between the first bearing 205 and the second bearing 206, pushing the second bearing 206 upward. At this point, the tension of the spring 203 is overcome, causing the pressing hook assembly 202 to swing away from the installation space, causing the structure on the pressing hook block 20201 to leave the surface of the wafer 4 and release the wafer 4. When the thrust is released, the return spring 304 causes the driving ring 302 to rotate counterclockwise, causing the ramp 301 to exit the first bearing 205 and the second bearing 206, returning the support cavity to its original position. Under the tension of spring 203, the pressing hook assembly 202 is reset, and the inclined structure on the pressing hook block 20201 presses again on the upper surface of the wafer 4, thereby clamping the wafer 4 together with the pressing block 20104. The four ramps are linked to simultaneously control the opening and clamping of the four fixing units 2.

[0044] In terms of material selection, the pressing block 20104 and the pressing hook block 20201 can be made of different materials, such as aluminum and ceramic, based on the wafer characteristics, contamination requirements, and temperature requirements. To address the temperature impact, organic materials with poor thermal conductivity but good temperature resistance, such as PEEK and PTFE, can be used.

[0045] like Figure 9As shown, the pressure block 20104 and the pressure hook block 20201 are made of aluminum alloy and PEEK materials, and the support fin 20103 uses flat support and inclined support. The surface temperature distribution of the lithium oxide wafer was obtained through finite element analysis. Under the same thermal power density, the use of aluminum alloy inclined fin support keeps the overall temperature below 125°C, and the temperature difference reaches 47°C. The use of PEEK inclined fin support, the overall temperature reaches 159°C, and the temperature difference is only 2°C, which is significantly better than the use of aluminum alloy. The use of PEEK flat fin support, the overall temperature reaches 156.5°C, the temperature difference is nearly 4°C, and the low temperature area is significantly larger. It is clear that the use of PEEK inclined fin support has a significant advantage in temperature uniformity.

[0046] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A wafer clamping device, characterized in that: The invention comprises a base plate (1), a fixing unit (2) and an unlocking mechanism (3), wherein at least three fixing units (2) are arranged on the periphery of the base plate (1), the unlocking mechanism (3) is provided on one side of the base plate (1), and an installation space for placing a wafer (4) is provided on the other side; the unlocking mechanism (3) moves relative to one end of the fixing unit (2), so that the other end of the fixing unit (2) moves toward the installation space for clamping or moves away from the installation space for release; The unlocking mechanism (3) comprises a parallel link mechanism (303) and a driving ring (302) for arranging the fixing units (2); the driving ring (302) is arranged below the base plate (1); the parallel link mechanism (303) is hingedly connected to the driving ring (302) on the side away from the base plate (1); a slope (301) corresponding to the number of fixing units (2) is provided on the radial end face of the driving ring (302); the slope (301) is arranged adjacent to the base plate (1); When the parallel link mechanism (303) moves in a horizontal displacement, it drives the driving ring (302) to rotate, thereby driving the ramp (301) to enter or leave the fixed unit (2).

2. The wafer holding device according to claim 1, wherein: A certain distance h is maintained between the wafer placed in the installation space and the substrate (1).

3. The wafer holding device according to claim 1, wherein: The fixing unit (2) is provided with a supporting fin (20103) for supporting the wafer.

4. The wafer holding device according to claim 1, wherein: The displacement movement of the unlocking mechanism (3) includes a horizontal displacement movement and a rotational movement that is converted into a rotational movement acting on the fixing unit (2), so that the fixing unit (2) is swung toward the installation space in an expanded manner.

5. The wafer holding device according to claim 1, wherein: The base plate (1) is a hollow annular plate.

6. The wafer holding device according to claim 1, wherein: One corner of the parallel link mechanism (303) is a power input end, and the other corner is provided with a return spring (304). The return spring (304) and the power input end are located at two diagonal corners of the parallel link mechanism (303).

7. The wafer holding device according to claim 1, wherein: The thickness of the slope (301) gradually increases in a clockwise direction along the circumference of the driving ring (302).

8. The wafer holding device according to claim 1, wherein: The fixing unit (2) comprises a support assembly (201), a pressure hook assembly (202), a spring (203), a rotating shaft (204), a first bearing (205) and a second bearing (206); the support assembly (201) is mounted on the base plate (1), the pressure hook assembly (202) is arranged in the support assembly (201), and one end of the pressure hook assembly (202) is hinged to the support assembly (201) through the rotating shaft (204), and the other end extends out of the support assembly (201) to the installation space The spring (203) is connected to the pressure hook assembly (202) and the support assembly (201); the first bearing (205) is provided on the support assembly (201), and the second bearing (206) is provided on the pressure hook assembly (202); the second bearing (206) and the first bearing (205) are arranged opposite to each other up and down, and a support cavity for accommodating the driving ring (302) is formed therebetween; the spring (203) and the second bearing (206) are connected to two opposite sides of the pressure hook assembly (202); When the driving ring (302) rotates to cause the slope (301) to open the support cavity, the pressing hook assembly (202) swings in a direction away from the installation space; when the driving ring (302) rotates in the opposite direction to restore the support cavity, the spring (203) pulls the pressing hook assembly (202) to swing in a direction close to the installation space.

9. The wafer holding device according to claim 8, wherein: The pressure hook assembly (202) comprises a rotating shaft block (20202) and a pressure hook block (20201) arranged on the rotating shaft block (20202); the rotating shaft block (20202) is hinged to the support assembly (201); and the upper end of the pressure hook block (20201) is provided with a structure inclined toward the installation space.

10. The wafer holding device according to claim 8, wherein: The support assembly (201) comprises a support block (20101), a connecting block (20102), a supporting fin (20103) and a pressing block (20104); the connecting block (20102) is a U-shaped structure with an opening; the support block (20101) is arranged at the opening; one end of the support block (20101) is connected to the connecting block (20102); the other end is provided with a horizontally protruding pressing block (20104) for abutting against the upper end surface of the substrate (1); the upper end of the pressing block (20104) is provided with the supporting fin (20103); the pressing hook assembly (202) is arranged in the U-shaped cavity of the connecting block (20102), and the upper end of the pressing hook assembly (202) extends out of the support block (20101) on a side close to the supporting fin (20103); The lower end of the pressure hook assembly (202) is hinged to the connecting block (20102); the spring (203) is respectively connected to the support block (20101) and the lower end of the pressure hook assembly (202) in the U-shaped cavity of the connecting block (20102); the second bearing (206) and the first bearing (205) are on the same side as the pressure block (20104).

11. The wafer holding device according to claim 10, wherein: The supporting surface of the supporting fin (20103) is inclined toward the installation space.

12. The wafer holding device according to claim 10, wherein: The material of the pressing block (20104) and the pressing hook block (20201) is any one of aluminum, ceramic, PEEK and PTFE.

Images