Grinding and polishing clamp with pressurizing and lifting mechanism

Abstract

The grinding and polishing clamp comprises a clamp outer support, a center adsorption mechanism and the pressurization lifting mechanism, the clamp outer support comprises a shaft sleeve fixing plate, a top plate and a driving circular ring, the center adsorption mechanism comprises a vacuum adsorption face, a center shaft and a center shaft fixing plate, and the center shaft fixing plate is fixed to the top of the vacuum adsorption face. The middle shaft is fixedly arranged in the center of the middle shaft fixing plate, a vacuum pipe is arranged in the middle shaft and communicated with the vacuum adsorption face, and the pressurizing lifting mechanism is arranged on the side of the shaft sleeve and comprises a telescopic mechanism and a pressing lifting mechanism. The piston rod is used for driving a downward-pressing lifting part in a downward-pressing lifting cavity in the center shaft fixing plate to move up and down, the piston rod downwards presses or lifts the center shaft fixing plate when stretching out and drawing back, and a pressure sensor is arranged on the bottom face of the downward-pressing lifting cavity and used for detecting the pressure of the downward-pressing lifting part on the bottom face of the downward-pressing lifting cavity. The pressurization control accuracy of the grinding clamp is high, and the wafer machining quality can be improved.

Description

Technical Field

[0001] The invention relates to a grinding and polishing device, in particular to a grinding and polishing fixture with a pressurizing and pulling mechanism. Background Art

[0002] During the surface treatment of semiconductor wafers and materials, they need to be ground and polished. Grinding is to subtract thickness, remove a certain thickness of material, make the wafer and material thinner as a whole and achieve a good TTV surface. Polishing is to brighten and improve the surface, using polishing pads and polishing liquids to improve the surface damage layer and roughness.

[0003] During the grinding and polishing process, the fixture absorbs the wafer and material for precision processing on the grinding and polishing machine. During processing, the fixture needs to apply a certain amount of pressure on the surface of the wafer / material to ensure that the wafer / material is processed correctly.

[0004] At present, most of the clamp pressurization methods mostly use the central cylinder 100 to pressurize the adsorption surface in the center of the clamp, thereby applying pressure to the wafer. The pressure control is also mainly to control the pressure of the CDA gas in and out of the cylinder, which cannot detect the pressure applied to the wafer surface in real time. In addition, the design of the central cylinder is easy to increase the height and center of gravity of the clamp as a whole, so that the turning space of the clamp becomes larger, and the overall operating space of the machine becomes larger, which is not conducive to the miniaturization of the machine; and the high center of gravity will deteriorate the stability of the overall clamp during grinding and polishing. Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the task of the present invention is to provide a grinding and polishing fixture with a pressurized and pulled mechanism to solve the problem of poor wafer grinding and polishing quality caused by low pressure control accuracy and poor stability.

[0006] The technical solution of the present invention is as follows: a grinding and polishing fixture with a pressurized lifting mechanism, including a fixture outer bracket and a central adsorption mechanism, and also including a pressurized lifting mechanism, the fixture outer bracket includes a shaft sleeve fixing plate, a top plate and a driving ring, the driving ring is located below the shaft sleeve fixing plate and is fixedly connected to the shaft sleeve fixing plate, the top plate is located above the shaft sleeve fixing plate, the central adsorption mechanism includes a vacuum adsorption surface, a central axis and a central axis fixing plate, the central axis fixing plate is fixed on the top of the vacuum adsorption surface, the central axis is fixedly arranged in the center of the central axis fixing plate, a vacuum tube is arranged in the central axis, and the vacuum tube is connected to the vacuum adsorption surface. The two surfaces are connected, the pressurizing and lifting mechanism is arranged on the side of the sleeve, the pressurizing and lifting mechanism includes a telescopic mechanism and a downward pressing and pulling mechanism, the telescopic mechanism is fixedly arranged between the sleeve fixing plate and the top plate, the downward pressing and pulling mechanism includes a downward pressing and pulling cavity arranged on the middle axis fixing plate, a downward pressing and pulling member movable up and down is arranged in the downward pressing and pulling cavity, the downward pressing and pulling member is fixedly connected to the piston rod of the telescopic mechanism, the piston rod presses down or pulls the middle axis fixing plate when it is telescoped, and a pressure sensor is provided on the bottom surface of the downward pressing and pulling cavity for detecting the pressure of the downward pressing and pulling member on the bottom surface of the downward pressing and pulling cavity.

[0007] Furthermore, a sealing rubber pad is provided in the pressing and pulling cavity, an edge of the sealing rubber pad is clamped on the wall surface of the pressing and pulling cavity, and the sealing rubber pad is located between the pressing and pulling member and the pressure sensor.

[0008] Furthermore, the sealing rubber pad is fixedly connected to the pressing and lifting member.

[0009] Furthermore, a spring sheet is provided above the pressure sensor, and the pressure sensor is triggered after the downward pressing and pulling member overcomes the elastic force of the spring sheet.

[0010] Furthermore, a cover plate is fixed on the top of the downward pressing and pulling cavity, and the cover plate is used to fix the sealing rubber pad, and the downward pressing and pulling member is provided with a pulling limit by the cover plate.

[0011] Furthermore, at least two pressurizing and pulling mechanisms are provided and are equally distributed on the circumference of the sleeve.

[0012] Furthermore, a fixing seat is fixed on the shaft sleeve fixing plate, the top of the telescopic mechanism is fixedly connected to the top plate, and the bottom of the telescopic mechanism is fixedly connected to the fixing seat.

[0013] Furthermore, a shaft sleeve is fixed at the center of the shaft sleeve fixing plate, a shaft sealing cover is provided on the upper part of the shaft sleeve, the shaft sealing cover is in sealing contact with the bottom surface of the top plate, and the central shaft seal is penetrated in the shaft sleeve.

[0014] Furthermore, a threaded column is provided on the top of the shaft sleeve, and the lower end of the shaft sealing cover is connected to the threaded column through a thread. The height of the shaft sealing cover can be adjusted by rotating the shaft sealing cover, and the sealing effect can also be ensured by the shaft sealing cover to support the top plate.

[0015] Furthermore, a rotary joint is provided in the center of the top plate, the vacuum tube passes through the top plate upward, a buffer area is provided between the bottom vacuum interface of the rotary joint and the top opening of the vacuum tube, and a filter is provided at the bottom vacuum interface of the rotary joint.

[0016] The advantages of the present invention compared with the prior art are: The pressure of the present invention is adjustable and controllable, easy to operate, and suitable for various thicknesses and various wafer materials. The pressure control accuracy of the present invention is better than 5%, which is 10% of the design accuracy in the prior art; the TTV of the 6-8 inch wafer processed by the present invention is less than or equal to 6 microns, while the prior art is 10-12 microns. The present invention greatly improves the pressure accuracy, improves the wafer index after processing, and improves the wafer quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of a grinding and polishing fixture in the prior art.

[0018] Figure 2 It is a schematic diagram of the three-dimensional structure of a polishing fixture with a pressurizing and pulling mechanism according to an embodiment.

[0019] Figure 3 It is a schematic diagram of the cross-section structure of a polishing fixture with a pressurizing and pulling mechanism according to an embodiment.

[0020] Figure 4 for Figure 3 Schematic diagram of the local structure at point A.

[0021] Figure 5 It is a schematic diagram of the state of the polishing fixture with a pressurizing and pulling mechanism of the embodiment falling naturally on the vacuum adsorption surface.

[0022] Figure 6 It is a schematic diagram of the state of the polishing fixture with a pressurized lifting mechanism in the embodiment when the cylinder is pressed down.

[0023] Figure 7 It is a schematic diagram of the state of the polishing fixture with a pressurized lifting mechanism in the embodiment when being lifted by a cylinder. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the embodiments, but are not intended to limit the present invention.

[0025] Please combine Figures 2 to 4As shown, the present embodiment involves a polishing fixture with a pressurized lifting mechanism, including a fixture outer bracket, a central adsorption mechanism, a pressurized lifting mechanism and a rotary joint part. The fixture outer bracket is mainly composed of a driving ring 1, a leg 301, a shaft sleeve fixing plate 6, a shaft sleeve 17, a shaft sealing cover 15, a top plate 8, a counterweight 10, etc., which mainly plays the role of bearing weight and stabilizing the fixture. The central adsorption surface mechanism can move up and down with the cooperation of the shaft sleeve 17, and it is mainly composed of a vacuum adsorption surface 4, a vacuum tube 9, a central axis fixing plate 5, a central axis 18, etc. The pressurized lifting mechanism is mainly composed of a cylinder 7 and a downward pressure and lifting mechanism 20, a pressure sensor 21, a pressure display unit 304, etc. The rotary joint part is mainly composed of a rotary joint 11, an adapter plate 12, a rotary joint fixing plate 13, a vacuum tube sealing ring 14, etc.

[0026] The sleeve 17 is fixed at the center of the sleeve fixing plate 6, and the three legs 301 and the leg fixing screws 302 connect the driving ring 1 and the sleeve fixing plate 6 into a whole. The bottom of one or more cylinders 7 is fixed to the outer edge of the sleeve fixing plate 6 through the cylinder fixing seat 19. The top of the cylinder 7 is fixedly connected to the top plate 8 by screws. The cylinder 7 can choose an electric cylinder of suitable size and function. The number of cylinders can be 1 to more than one, and when there are more than one, they need to be evenly distributed, and the use space of the fixture needs to be considered. The cylinder diameter can be selected according to the type, size, and downward pressure of the wafer material being processed, and the cylinder diameter ranges from 10mm to 40mm. It is best to choose the same model for multiple cylinders, and they are located on the circumference of the sleeve 17 and distributed equally on the circumference to make the pressure at each point uniform and stable and synchronize the pressurization.

[0027] A threaded column 16 is provided on the upper part of the shaft sleeve 17, and the shaft sealing cover 15 cooperates with the threaded column 16 through threads. The shaft sealing cover 15 can adjust the height up and down through the threads, and finally contacts the sealing ring in the sealing groove at the bottom of the top plate 8 to form a seal for the shaft sleeve 17 and the middle shaft 18, preventing dust and moisture from entering the gap between the two and affecting the accuracy. The shaft sealing cover 15 also plays the role of supporting the top plate 8. The counterweight block 10 is fixed to the top plate 8 by two quick release pins.

[0028] The central axis 18 is fixed at the center of the central axis fixing plate 5. The vacuum adsorption surface 4 is connected to the vacuum tube 9, which passes through the central axis 18 and communicates with the vacuum adsorption surface 4. The vacuum adsorption surface 4 is fixed as a whole at the bottom of the central axis fixing plate 5. The central axis 18 is inserted into the shaft sleeve 17 and can move freely up and down in the shaft sleeve 17. For the vacuum adsorption surface 4, a porous ceramic adsorption surface, a stainless steel adsorption surface with grooves, or a ceramic convex adsorption surface with a through hole in the center can be selected.

[0029] A downward pressure and lifting cavity is dug near the outer edge of the central axis fixing plate 5, and a pressure sensor 21 is arranged at the center of the bottom surface of the downward pressure and lifting cavity. The tail cable of the pressure sensor 21 passes through the gap between the vacuum tube 9 and the central axis 17 to the top of the shaft sealing cover 15, and passes through the top side hole to connect with the pressure display unit 304. The pressure sensor 105 can be a convex point pressure sensor or a thin film pressure sensor. A metal spring 105 is installed on the upper part of the pressure sensor 21. The downward pressure and lifting member 102 is connected to the cylinder rod 22 of the cylinder 7 through the connecting member 103. The bottom of the downward pressure and lifting member 102 is fixedly connected to the fastening plate 106 by screws and fixes the sealing pad 104 in the center. The edge of the sealing pad 104 is fixed to the central axis fixing plate 5 through the cover plate 101. On the one hand, the cover plate 101 fixes the sealing pad 104, which prevents moisture and dust from entering the pressure sensor, and on the other hand, provides a limit for the lifting of the downward pressure and lifting member 102.

[0030] The adapter plate 12 is fixed to the center of the top plate 8 by screws. The rotary joint 11 is fixed to the center of the rotary joint fixing plate 13. The two are fixed to the adapter plate 12 as a whole. There is a vacuum tube sealing ring 14 at the bottom of the adapter plate 12. The vacuum tube 9 can pass through the vacuum sealing ring 14 and move up and down. The adapter plate 12, the rotary joint fixing plate 13, the rotary joint 11 and the vacuum tube 9 jointly form an intermediate buffer area C1. A filter screen 24 is fixed on the top of the intermediate buffer area C1 to prevent possible grinding and polishing liquid and water from being sucked into the vacuum tube to prevent them from being further sucked into the rotary joint 11 and other pipelines. The center of the top of the rotary joint 11 is the L1 inlet pipeline and joint, and the lateral sides have L2, L3, L4 (not shown) inlet pipeline joints. The center of the bottom of the rotary joint 11 is connected to L1 and is connected to the C1 area. The lateral sides of the bottom of the rotary joint 11 have outlet pipeline joints corresponding to L2, L3, L4 (not shown). Among them, L1 mainly provides vacuum and CDA, L2 and L3 provide CDA for the cylinder, and L4 provides DIW, whose water outlet is connected to C1, providing cleaning water for the adsorption surface 4 through the vacuum tube 9 and the chamber area C2 of the adsorption surface 4.

[0031] The processing operation process of wafer 2 is as follows: Figure 5 As shown, when the C1 area is vacuum, the vacuum adsorption surface 4 adsorbs the substrate 3 and the wafer 2. When the cylinder 7 is connected to the atmosphere, the vacuum adsorption surface 4 and the wafer 2 fall as a whole under the action of the deadweight of the central adsorption mechanism. When the wafer 2 contacts the disk surface, the bottom surface of the wafer 2 is flush with the bottom surface of the driving ring 1. At this time, the pressure on the wafer 2 = F1, which is the deadweight of the central adsorption mechanism.

[0032] like Figure 6As shown, when the bottom surface of the wafer 2 is flush with the bottom surface of the driving ring 1 and the disk surface, CDA is introduced into the upper part of the cylinder 7, and the piston 23 is pressed down to press the cylinder rod 22 down, and the pressing and pulling member 102 is pressed down to contact the metal spring 105. When the pressure continues to be pressed down, the metal spring 105 is pressed down to the central surface of the pressure sensor 21 and finally stabilized to the set pressure. At the same time, the downward pressure is displayed on the pressure display unit 304. When a double cylinder 7 is used, the downward pressure of the left and right cylinders 7 is F2 and F3 respectively. When the left and right cylinders use the same cylinder diameter model and the same CDA pressure, F2=F3. At this time, the pressure on the wafer = F1+F2+F3. The pressure display unit 304 can be connected to the main control computer and software by wireless means, and the real-time pressure can also be displayed in the software. The pressure display unit 304 can be selected as a single-channel or multi-channel display unit according to the number of cylinders.

[0033] like Figure 7 As shown, when the grinding and polishing is finished, the upper air intake of the cylinder 7 is switched to the atmosphere, and the lower air intake is switched to CDA, and the cylinder rod 22 is lifted upward, driving the downward pressing and pulling member 102 to lift away from the metal spring 105, and the metal spring 105 returns to its original state and does not contact the pressure sensor 21. After the cylinder rod continues to rise, the downward pressing and pulling member 102 contacts the top of the cover plate 101, and then the entire central axis fixing plate 5 is lifted, the central adsorption mechanism is lifted as a whole, and the wafer is away from the disk surface until the central axis fixing plate 5 contacts the limit screw (not shown) and stops.

[0034] After that, the clamp moves to the unloading mechanism. When it reaches the unloading position, the cylinder is depressurized, the central adsorption mechanism falls under the action of its own weight, and the vacuum adsorption surface 4 and the wafer 2 fall as a whole. When the wafer 2 falls to the unloading position, the vacuum in the C1 area is disconnected, L1 switches from vacuum to the corresponding CDA pressure pipeline, and the C1 area changes from a vacuum area to a pressure area. Through the vacuum tube 9 and the C2 area, pressure is provided to the substrate 3, so that the substrate 3 with the wafer 2 attached is separated from the vacuum adsorption surface 4, and the unloading is completed. After the unloading is completed, the wafer 2 and the substrate 3 are taken away. At this time, L4 (not shown) is connected to DIW and passed into the C1 area. Under the pressure of CDA, water is rinsed on the C1 area, the vacuum tube 9 and the C2 area, and the surface of the vacuum adsorption surface 4. After the rinsing is completed, the DIW of L4 is disconnected, and CDA is continued to be purged on the C1 area, the vacuum tube 9 and the C2 area, and the surface of the vacuum adsorption surface 4 to dry the moisture. After the drying time is over, L1 switches to atmospheric pressure, and areas such as C1 and C2 also return to atmospheric pressure. The fixture is in a waiting state, ready to receive the next wafer processing operation.

Claims

1. A polishing fixture with a pressurizing and pulling mechanism, comprising an outer fixture bracket and a central adsorption mechanism, characterized in that: It also includes a pressurizing and pulling mechanism, the outer bracket of the clamp includes a sleeve fixing plate, a top plate and a driving ring, the driving ring is located below the sleeve fixing plate and is fixedly connected to the sleeve fixing plate, the top plate is located above the sleeve fixing plate, the central adsorption mechanism includes a vacuum adsorption surface, a central axis and a central axis fixing plate, the central axis fixing plate is fixed on the top of the vacuum adsorption surface, the central axis is fixedly arranged in the center of the central axis fixing plate, a vacuum tube is arranged in the central axis, the vacuum tube is connected to the vacuum adsorption surface, and the pressurizing and pulling mechanism is arranged on the sleeve On the side, the pressurizing and pulling mechanism includes a telescopic mechanism and a downward pressing and pulling mechanism. The telescopic mechanism is fixedly arranged between the sleeve fixing plate and the top plate. The downward pressing and pulling mechanism includes a downward pressing and pulling cavity arranged on the central axis fixing plate. A downward pressing and pulling member that can move up and down is arranged in the downward pressing and pulling cavity. The downward pressing and pulling member is fixedly connected to the piston rod of the telescopic mechanism. When the piston rod is extended or retracted, it presses down or pulls the central axis fixing plate. The bottom surface of the downward pressing and pulling cavity is provided with a pressure sensor for detecting the pressure of the downward pressing and pulling member on the bottom surface of the downward pressing and pulling cavity.

2. The polishing fixture with a pressurizing and pulling mechanism according to claim 1 is characterized in that: A sealing rubber pad is provided in the pressing and pulling cavity, the edge of the sealing rubber pad is clamped on the wall surface of the pressing and pulling cavity, and the sealing rubber pad is located between the pressing and pulling member and the pressure sensor.

3. The polishing fixture with a pressurizing and pulling mechanism according to claim 2 is characterized in that: The sealing rubber pad is fixedly connected to the pressing and pulling member.

4. The polishing fixture with a pressurizing and pulling mechanism according to claim 2, characterized in that: A spring sheet is arranged above the pressure sensor, and the pressure sensor is triggered after the downward pressing and pulling member overcomes the elastic force of the spring sheet.

5. The polishing fixture with a pressurizing and pulling mechanism according to claim 2, characterized in that: A cover plate is fixed on the top of the downward pressing and pulling cavity, and the cover plate is used to fix the sealing rubber pad. The downward pressing and pulling member is provided with a lifting limit by the cover plate.

6. The polishing fixture with a pressurizing and pulling mechanism according to claim 1, characterized in that: The pressurizing and pulling mechanisms are provided in no less than two portions and are equally distributed on the circumference of the central axis.

7. The polishing fixture with a pressurizing and pulling mechanism according to claim 1, characterized in that: A fixing seat is fixed on the shaft sleeve fixing plate, the top of the telescopic mechanism is fixedly connected to the top plate, and the bottom of the telescopic mechanism is fixedly connected to the fixing seat.

8. The polishing fixture with a pressurizing and pulling mechanism according to claim 1, characterized in that: A shaft sleeve is fixed at the center of the shaft sleeve fixing plate, a shaft sealing cover is provided on the upper part of the shaft sleeve, the shaft sealing cover is in sealing contact with the bottom surface of the top plate, and the central shaft seal is penetrated in the shaft sleeve.

9. The polishing fixture with a pressurizing and pulling mechanism according to claim 8, characterized in that: A threaded column is arranged on the top of the shaft sleeve, and the lower end of the shaft sealing cover is connected with the threaded column through a thread.

10. The polishing fixture with a pressurizing and lifting mechanism according to claim 1, characterized in that: A rotary joint is provided in the center of the top plate, the vacuum tube passes through the top plate upwards, a buffer area is provided between the bottom vacuum interface of the rotary joint and the top opening of the vacuum tube, and a filter is provided at the bottom vacuum interface of the rotary joint.

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