A SC-cut wafer circumferential surface polishing device and process method

Abstract

A SC-cut wafer circumferential surface polishing device and process method, in which a workbench, a driving motor, a transmission mechanism, a polishing upper plate, a polishing lower plate and a planetary gear train are arranged in the polishing device; the polishing lower plate and the polishing upper plate are arranged above the table surface of the workbench, and the driving motor is arranged below the table surface of the workbench; the driving motor drives the polishing lower plate and the polishing upper plate to rotate in opposite directions through the transmission mechanism, the polishing lower plate and the polishing upper plate are arranged relatively, and a planetary gear train is arranged between the polishing lower plate and the polishing upper plate; the planetary gear train is provided with a gear ring, a cruise wheel and a sun wheel, the gear ring is fixed on the table surface of the workbench, the sun wheel is coaxially assembled with the polishing lower plate, the cruise wheel is externally meshed with the gear ring and the sun wheel, a rectangular long hole is arranged on the cruise wheel, and a crystal lump workpiece is assembled in the rectangular long hole of the cruise wheel in a clearance fit manner. The present invention achieves the purpose of improving the edge and side wall quality of the wafer by improving the processing technology and processing equipment of the quartz wafer.

Description

Technical Field

[0001] The invention relates to the technical field of quartz wafer processing, in particular to a device and a process method suitable for polishing the circumferential surface of an SC-cut quartz wafer. Background Art

[0002] SC-cut quartz crystals have unparalleled advantages over other cut crystals in terms of instantaneous thermal compensation, short stability, long-term aging, and radiation resistance, and are especially important in oven-controlled crystal oscillators (OCXOs).

[0003] In order to improve the stability of SC-cut wafers, a large etching coefficient is usually used. However, this deep etching process will cause the internal defects of the crystal to be highlighted, resulting in broken edges and crescent-shaped defects, which will greatly reduce the yield rate of the wafer production line. At present, the process flow of SC-cut wafer forming is: sticking → cutting → rolling → grinding, in which the grinding process uses 3um grinding sand to grind the circumferential surface of the crystal lump side wall. After the wafer is etched through the above process, the proportion of etching defects on the side wall is relatively large. To solve this problem, one method is to use high-quality crystal raw materials, but the disadvantage of this method is that the cost will increase exponentially; another method is to improve the smoothness of the circumference of the crystal lump side wall by improving the forming process, and improve the edge and side wall quality of the wafer. For this purpose, it is necessary not only to improve the processing process of the quartz wafer, but also to optimize the design of the matching processing equipment. Summary of the invention

[0004] The present invention provides a SC-cut wafer circumferential surface polishing device and a process method, aiming to improve the edge and side wall quality of the wafer by improving the processing technology and processing equipment of the quartz wafer.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A SC-cut wafer circumferential surface polishing device comprises a workbench, a driving motor, a transmission mechanism, a polishing upper plate, a polishing lower plate and a planetary gear train; the workbench is arranged on a horizontal ground, the polishing lower plate and the polishing upper plate are arranged above the workbench surface, and the driving motor is arranged below the workbench surface; the driving motor drives the polishing lower plate and the polishing upper plate to rotate through the transmission mechanism, the polishing lower plate and the polishing upper plate are arranged relatively to each other, and the two rotate in opposite directions, and a planetary gear train is arranged between the polishing lower plate and the polishing upper plate; the planetary gear train is provided with a gear ring, a cruise wheel and a sun wheel, the gear ring is fixed on the workbench surface, the sun wheel is coaxially assembled with the polishing lower plate, the cruise wheel is internally meshed with the gear ring for transmission, and externally meshed with the sun wheel for transmission, a rectangular long hole is arranged on the cruise wheel, and a crystal lump workpiece is assembled in the rectangular long hole of the cruise wheel in a clearance fit manner.

[0007] The above-mentioned SC cut wafer circular surface polishing equipment, the transmission structure adopts a gear transmission method, including a first gear transmission assembly and a second gear transmission assembly, a reversing wheel is provided in the second gear transmission assembly, and the first gear transmission assembly and the second gear transmission assembly cooperate to realize the synchronous reverse rotation of the polishing lower plate and the polishing upper plate.

[0008] The above-mentioned SC-cut wafer circumferential surface polishing equipment, the polishing lower plate is made of ductile iron; the polishing upper plate is made of aluminum alloy; the cruise ship is made of phenolic resin.

[0009] In the above-mentioned SC-cut wafer circumferential surface polishing equipment, the number of the cruise wheels is six groups, and they are evenly arranged in the annular space between the ring gear and the sun gear.

[0010] The above-mentioned SC-cut wafer circumferential surface polishing equipment is provided with four groups of rectangular long holes on each group of cruise ships.

[0011] A method for polishing the circumferential surface of an SC-cut wafer is provided, wherein the polishing device is used to polish the sidewall of an SC-cut wafer, including two steps of rough polishing and fine polishing, and the control process is as follows:

[0012] a. Rough polishing process: place the ground crystal lump workpiece in the rectangular long hole of the cruise ship, adjust the polishing upper plate to the working position, debug the polishing equipment, ensure that the components of the planetary gear train run smoothly, inject rough polishing liquid, start the drive motor, control the speed of the polishing lower plate to ≤25 rpm, and control the polishing time within 25 minutes. Then take out the crystal lump workpiece and clean and remove the residual polishing liquid;

[0013] b. Fine polishing process: place the rough-polished crystal lump workpiece in the rectangular long hole of the cruise ship, adjust the polishing upper plate to the working position, debug the polishing equipment, ensure the smooth operation of the planetary gear system components, inject fine polishing liquid, start the drive motor, control the speed of the polishing lower plate to ≤25 rpm, and control the polishing time within 18 minutes. Then take out the crystal lump workpiece, clean and remove the residual polishing liquid, and complete the side wall polishing operation of the crystal lump workpiece.

[0014] In the above-mentioned SC-cut wafer peripheral surface polishing process method, in the step a, the diameter of the particles in the injected coarse polishing liquid is 2.3 μm (identified particle size).

[0015] In the above-mentioned SC-cut wafer peripheral surface polishing process method, in the step b, the particle diameter in the injected fine polishing liquid is 1 μm (identified particle size).

[0016] In the above-mentioned SC-cut wafer peripheral surface polishing process method, in the steps a and b, the supply speed of the fine polishing liquid or the rough polishing liquid is 25 to 30 ml / min.

[0017] In the above-mentioned SC-cut wafer peripheral surface polishing process method, in the step a, the rough polishing amount is controlled at 5 μm; in the step b, the fine polishing amount is controlled at 3 μm.

[0018] The present invention provides a SC-cut wafer circumferential surface polishing device and process method, which can complete the rough polishing and fine polishing of the side wall of the SC-cut crystal lump through the polishing device. During the rough polishing and fine polishing process, the polishing disc rotation speed and the polishing liquid supply speed are controlled to control the rough polishing amount to 5μm and the fine polishing amount to 3μm, thereby improving the smoothness of the side wall of the SC-cut crystal lump. Experiments have proved that: by using the polishing device and process method described in the present invention, the proportion of side wall defects is reduced by 16% after the SC-cut wafer undergoes the etching process. It can be seen that the present invention achieves the purpose of improving the edge and side wall quality of the wafer by improving the processing technology and processing equipment of the quartz wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of the circumferential surface polishing equipment of the SC-cut wafer of the present invention;

[0020] Figure 2 It is the assembly structure diagram of the polishing upper plate, polishing lower plate and planetary gear train in the polishing equipment;

[0021] Figure 3 yes Figure 2 Schematic diagram of the AA section structure;

[0022] Figure 4 It is a schematic diagram of the cruise ship structure in the planetary gear system;

[0023] Figure 5 yes Figure 4 Schematic diagram of the BB cross-section structure.

[0024] The list of reference numbers in the figure is:

[0025] 1. Polishing upper plate; 2. Cruise ship; 2-1. Rectangular long hole; 3. Polishing lower plate; 4. Ring gear; 5. Workbench; 6. Driving motor; 7. Transmission mechanism; 7-1. First gear transmission assembly; 7-2. Second gear transmission assembly; 8. Crystal workpiece; 9. Sun gear. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0027] See Figure 1. Figure 2 , Figure 3The SC-cut wafer circumferential surface polishing device of the present invention comprises a workbench 5, a driving motor 6, a transmission mechanism 7, a polishing upper plate 1, a polishing lower plate 3 and a planetary gear train; the workbench 5 is arranged on a horizontal ground, the polishing lower plate 3 and the polishing upper plate 1 are arranged above the workbench 5, and the driving motor 6 is arranged below the workbench 5; the driving motor 6 drives the polishing lower plate 3 and the polishing upper plate 1 to rotate through the transmission mechanism 7, the polishing lower plate 3 and the polishing upper plate 1 are arranged opposite to each other, and the two rotate in opposite directions, and a planetary gear train is arranged between the polishing lower plate 3 and the polishing upper plate 1.

[0028] See also Figure 2 , Figure 3 The SC-cut wafer circumferential surface polishing equipment described in the present invention comprises a planetary gear train having a ring gear 4, a cruise wheel 2 and a sun wheel 9, wherein the ring gear 4 is fixed on the surface of a workbench 5, the sun wheel 9 is coaxially assembled with the polishing lower plate 3, the cruise wheel 2 is internally meshed with the ring gear 4 for transmission, and the cruise wheel 2 is externally meshed with the sun wheel 9 for transmission, and the number of cruise wheels 2 is preferably 6 groups.

[0029] See also Figure 3 , Figure 4 , Figure 5 The SC-cut wafer circumferential surface polishing equipment described in the present invention has rectangular long holes 2-1 on each cruise wheel 2, and the number of the rectangular long holes 2-1 is preferably 4 groups, which are evenly arranged along the circumferential direction of the cruise wheel 2. The crystal lump workpiece 8 is assembled in the rectangular long holes 2-1 of each group of cruise wheels 2 in a clearance fit manner, and the crystal lump workpiece 8 can rotate around the central axis in the rectangular long holes.

[0030] See also Figure 1 , Figure 2 The SC-cut wafer circumferential surface polishing equipment described in the present invention, the transmission structure 7 adopts a gear transmission method, including a first gear transmission assembly 7-1 and a second gear transmission assembly 7-2, and a reversing wheel is provided in the second gear transmission assembly 7-2. The first gear transmission assembly 7-1 and the second gear transmission assembly 7-2 cooperate to realize the synchronous reverse rotation of the polishing lower plate 3 and the polishing upper plate 1.

[0031] See also Figures 1 to 5 The present invention also provides a method for polishing the circumferential surface of an SC-cut wafer. The method uses the above-mentioned polishing equipment to complete the sidewall polishing of the SC-cut wafer, including two steps of rough polishing and fine polishing. The control process is as follows:

[0032] a. Rough polishing process: place the ground crystal workpiece 8 in the rectangular long hole 2-1 of the cruise ship 2, then adjust the polishing upper plate 1 to the working position, debug the polishing equipment, ensure that the components of the planetary gear train run smoothly, inject rough polishing liquid at a speed of 25-30 ml / min, the particle diameter in the rough polishing liquid is 2.3 um (marked particle size), start the drive motor 6, control the speed of the polishing lower plate 3 to ≤25 rpm, and control the polishing time within 25 minutes, then take out the crystal workpiece 8, and clean and remove the residual polishing liquid;

[0033] b. Fine polishing process: place the rough-polished crystal lump workpiece 8 in the rectangular long hole 2-1 of the cruise ship 2, then adjust the polishing upper plate 1 to the working position, debug the polishing equipment, ensure the smooth operation of the planetary gear system components, inject fine polishing liquid at a speed of 25-30 ml / min, the particle diameter in the fine polishing liquid is 1 um (marked particle size), start the drive motor 6, control the speed of the polishing lower plate 3 to ≤25 rpm, and control the polishing time within 18 minutes. Then take out the crystal lump workpiece 8, clean and remove the residual polishing liquid, and complete the side wall polishing operation of the crystal lump workpiece.

[0034] In the above step a, the rough polishing amount is controlled at 5 μm; in the above step b, the fine polishing amount is controlled at 3 μm.

Claims

1. An SC-cut wafer circumferential surface polishing device and process method, characterized in that: Polishing equipment is used to complete the polishing of the side wall of the SC-cut crystal lump, including two processes: rough polishing and fine polishing. The control process is as follows: a. Rough polishing process, placing the ground crystal workpiece (8) in the rectangular long hole (2-1) of the cruise ship (2), adjusting the polishing upper plate (1) to the working position, debugging the polishing equipment, ensuring that the components of the planetary gear train run smoothly, injecting rough polishing liquid, starting the drive motor (6), controlling the speed of the polishing lower plate (3) to ≤25 rpm, and controlling the polishing time within 25 minutes, then taking out the crystal workpiece (8), cleaning and removing the residual polishing liquid; the particle diameter of the injected rough polishing liquid is 2.3 μm (marked particle size); the rough polishing amount is controlled to be 5 μm; b. Fine polishing process, placing the rough polished crystal workpiece (8) in the rectangular long hole (2-1) of the cruise ship (2), adjusting the polishing upper plate (1) to the working position, debugging the polishing equipment, ensuring that the components of the planetary gear train run smoothly, injecting fine polishing liquid, starting the drive motor (6), controlling the speed of the polishing lower plate (3) to ≤25 rpm, and controlling the polishing time within 18 minutes, then taking out the crystal workpiece (8), cleaning and removing the residual polishing liquid, and completing the side wall polishing operation of the crystal workpiece; the particle diameter of the injected fine polishing liquid is 1 um (marked particle size); the fine polishing amount is controlled to be 3 μm; The polishing device comprises a workbench (5), a driving motor (6), a transmission mechanism (7), a polishing upper plate (1), a polishing lower plate (3) and a planetary gear train; the workbench (5) is arranged on a horizontal ground, the polishing lower plate (3) and the polishing upper plate (1) are arranged above the workbench (5), and the driving motor (6) is arranged below the workbench (5); the driving motor (6) drives the polishing lower plate (3) and the polishing upper plate (1) to rotate through the transmission mechanism (7); the polishing lower plate (3) and the polishing upper plate (1) are arranged relative to each other, and the rotation directions of the two are opposite. On the contrary, a planetary gear train is arranged between the polishing lower plate (3) and the polishing upper plate (1); the planetary gear train is provided with a ring gear (4), a cruise wheel (2) and a sun gear (9); the ring gear (4) is fixed on the table surface of the workbench (5); the sun gear (9) is coaxially assembled with the polishing lower plate (3); the cruise wheel (2) and the ring gear (4) are internally meshed for transmission; the cruise wheel (2) and the sun gear (9) are externally meshed for transmission; a rectangular long hole (2-1) is provided on the cruise wheel (2); and a crystal lump workpiece (8) is assembled in the rectangular long hole (2-1) of the cruise wheel (2) in a clearance fit manner; The transmission structure (7) adopts a gear transmission method, comprising a first gear transmission assembly (7-1) and a second gear transmission assembly (7-2), wherein a reversing wheel is provided in the second gear transmission assembly (7-2), and synchronous reverse rotation of the polishing lower plate (3) and the polishing upper plate (1) is achieved through the cooperation of the first gear transmission assembly (7-1) and the second gear transmission assembly (7-2); The polishing lower plate (3) is made of ductile iron; the polishing upper plate (1) is made of aluminum alloy; and the cruise ship (2) is made of phenolic resin.

2. The SC-cut wafer circumferential surface polishing equipment and process according to claim 1 is characterized in that: The number of the cruise wheels (2) is six, and they are evenly arranged in the annular space between the ring gear (4) and the sun gear (9).

3. The SC-cut wafer circumferential surface polishing equipment and process according to claim 2, characterized in that: Four groups of rectangular long holes are arranged on each group of cruise ships (2).

4. The SC-cut wafer circumferential surface polishing equipment and process according to claim 1, characterized in that: In the step a and the step b, the supply speed of the fine polishing liquid or the rough polishing liquid is 25-30 ml / min.

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