Silicon plasma distribution disk processing method
By performing steps such as planar grinding, positioning hole and small hole processing, flipping features, double-sided LAP grinding, mixed acid etching and polishing on the silicon plasma distribution disk blank, the problem of the roughness of the polished surface of the silicon plasma distribution disk being difficult to reach Ra0.05 was solved, and the roughness of the polished surface was improved to be lower than Ra0.05 and the surface finish was improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ADVANCED QUARTZ MATERIAL (HANGZHOU) CO LTD
- Filing Date
- 2024-08-26
- Publication Date
- 2026-06-30
AI Technical Summary
The surface roughness of existing silicon plasma shunt disks is difficult to achieve below Ra0.05, which cannot meet the requirements of extremely fine silicon wafer processing.
A silicon plasma distribution disk processing method is adopted, which includes steps such as planar grinding, positioning hole and small hole processing, flip feature processing, double-sided LAP grinding, mixed acid etching and polishing. First, the front and back features are processed on the silicon plasma distribution disk blank, then double-sided LAP grinding is performed to remove the tool marks generated during processing, and finally etching and polishing are performed to reduce the roughness of the polished surface.
The roughness of the polished surface of the silicon plasma distribution disk is lower than Ra0.05, which meets the requirements of extremely fine silicon wafer processing, reduces subsequent polishing time and improves surface finish.
Smart Images
Figure CN119098826B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of silicon component technology for chip etching, and specifically to a method for processing a silicon plasma shunt disk. Background Technology
[0002] Silicon components for chip etching refer to components that meet the performance requirements of semiconductor etching equipment and technology in terms of materials, structure, process, quality and precision, reliability and stability, such as... Figure 1 As shown, silicon plasma shunt disks are broadly categorized into structural components such as silicon plasma chucks (silicon spray heads), ESC electrostatic chucks, silicon rings, silicon electrodes, and silicon exhaust rings. In dry etching processes, the plasma needs to maintain uniform velocity and bombardment volume at all points when bombarding the wafer. During processing, an electromagnetic field is generated by energizing the upper electrode to accelerate and confine the plasma, and process gases are injected into the cavity through uniformly distributed nozzles on the upper electrode surface for shunt treatment. The silicon plasma shunt disk, serving as an electrode for applying additional voltage and a pathway for etching gas to enter the cavity, is an essential core component in the wafer manufacturing etching process.
[0003] Currently, 12-inch silicon wafer technology is developing towards extreme precision, with the world's leading level for large-size silicon wafers reaching 7 nm, and 7 nm demand will become mainstream in the next few years. The continuous reduction in linewidth places increasingly higher demands on silicon component processing. The requirements for silicon component products with smaller linewidths are mainly reflected in the precise control of parameters, such as surface and edge roughness, roundness, thickness of mechanical damage inside the micropores of silicon plasma shunt disks, and the morphology of the micropore edges. However, existing silicon plasma shunt disk processing techniques produce poor polishing results, making it difficult to meet the requirement of a polished surface roughness below Ra0.05. Summary of the Invention
[0004] In view of this, the present invention provides a method for processing a silicon plasma distribution disk to meet the requirement that the surface roughness of the polished silicon plasma distribution disk reaches Ra0.05 or less.
[0005] The technical solution adopted by this invention to solve its technical problem is:
[0006] A method for processing a silicon plasma distribution disk includes the following steps:
[0007] S1. Perform planar grinding on the silicon plasma distribution disk blank to grind the thickness of the silicon plasma distribution disk blank to the final product thickness +1-2mm, the parallelism to 0.09-0.15mm, and the flatness to 0.05-0.11mm.
[0008] S2. Machining positioning holes, small holes and other features on the silicon plasma distribution disk blank;
[0009] S3. Turn the silicon plasma distribution disk blank over and process the reverse side features;
[0010] S4. Perform double-sided LAP grinding on the silicon plasma distribution disk blank after feature processing.
[0011] S5. Use mixed acid to etch the polished silicon plasma distribution disk blank.
[0012] S6. Polish the etched silicon plasma distribution disk blank using a polishing machine.
[0013] Preferably, in step S2, the following steps are used to process the positioning holes, small holes, and other features on the silicon plasma distribution disk blank:
[0014] S21. Bonding onto the machine: Bond the silicon plasma distribution disk blank to the quartz plate, and place the bonded quartz plate and the silicon plasma distribution disk blank on the machine tool work platform and clamp them.
[0015] S22. Machining positioning holes: Use a 1-2mm diamond drill bit to pre-drill holes to a depth of 0.7-0.9mm;
[0016] S23. Machining small holes: Use a diamond drill bit to machine small holes, with a hole depth of 0.4-0.6 mm from the bottom surface of the silicon plasma distribution disk blank.
[0017] S24. Machining the waist hole features: The waist hole is machined using a 250-350 mesh metal matrix diamond tool with a diameter 2mm smaller than the diameter of the waist hole, leaving a 0.3-0.5mm allowance at the bottom of the waist hole;
[0018] S25. Machining the beveled surface features: The beveled surface is machined using a 60-80mm diameter, 450-550 mesh resin-based diamond abrasive tool.
[0019] S26. Groove characteristics: The groove is machined using a 30-60mm diameter, 150-250 mesh metal-based diamond tool, and the edges are chamfered.
[0020] S27. Polish the surface of the silicon plasma distribution disk blank and the surface of the small holes.
[0021] S28. Machining the outer diameter: Use a 30-60mm diameter, 150-250 mesh metal matrix diamond tool to machine the outer diameter, and perform chamfering on the outer diameter.
[0022] Preferably, in step S21, the bonding of the silicon plasma distribution disk blank to the quartz plate is performed using the following steps:
[0023] S211. A heating platform is used to heat the silicon plasma distribution disk blank and the quartz plate;
[0024] S212. After heating to 120℃, the silicon plasma distribution disk blank is bonded to the quartz plate using yellow stone wax.
[0025] Preferably, in step S3, the silicon plasma distribution disk blank is flipped over, and the reverse side features are processed using the following steps:
[0026] S31, Bonding onto the machine: Turn the silicon plasma distribution disk blank over and bond the surface of the silicon plasma distribution disk blank processed in step S2 to the quartz plate. Place the bonded quartz plate and the silicon plasma distribution disk blank on the machine tool work platform and clamp them.
[0027] S32. Polish the surface: Use a 250-300 mesh metal matrix diamond tool to rough polish the silicon plasma distribution disk blank by 0.4 mm, so that the waist hole that was not processed through in step S24 is exposed, and the waist hole becomes a through hole after polishing.
[0028] S33. Alignment: Alignment is performed through the waist hole to ensure that the placement direction and position of the silicon plasma distribution plate blank are consistent with those in step S2.
[0029] S34. Machining the countersunk hole: Use a 250-350 mesh metal matrix diamond tool with a diameter 2mm smaller than the countersunk hole diameter to machine the countersunk hole, and chamfer the edges of the countersunk hole.
[0030] S35. Groove features: The groove is machined using a 30-60mm diameter, 150-250 mesh metal-based diamond abrasive tool, and the edges are chamfered.
[0031] S36. Polish the surface of the silicon plasma distribution disk blank and the small hole surface;
[0032] S37. Machining outer diameter chamfer: Use a 30-60mm diameter, 150-250 mesh metal matrix diamond tool to machine the outer diameter chamfer.
[0033] Preferably, in step S4, the double-sided LAP grinding of the silicon plasma distribution disk blank after feature processing is performed by the following steps: using LAP 1500-2000 mesh abrasive powder to grind the upper and lower surfaces and the surface of the small holes of the silicon plasma distribution disk blank after feature processing.
[0034] Preferably, in step S5, when the silicon plasma distribution disk blank is etched with mixed acid, the etching amount of the small holes of the silicon plasma distribution disk blank is 0.02-0.04 mm, and the etching amount of the upper and lower surfaces is 0.01 mm on each side.
[0035] Preferably, in step S6, the silicon plasma distribution disk blank is polished using a polishing machine by the following steps: the small hole surface, the bevel surface and the surface on both sides of the silicon plasma distribution disk blank are polished sequentially using a polishing machine.
[0036] Preferably, when polishing the small hole surfaces on both sides of the silicon plasma distribution disk blank, the X-axis reciprocating polishing is performed, the polishing spindle angle is 1.5-1.9°, the polishing head pressure is 15-20KG, the polishing head speed is 1500-2000 rpm, the reciprocating polishing feed speed is 15-25 mm / min, the turntable speed is 80-100 rpm, and the polishing time is 1-1.2 hours.
[0037] Preferably, when polishing the inclined surfaces of the front and back sides of the silicon plasma distribution disk blank, fixed-angle fixed-point polishing is adopted. The polishing spindle angle is consistent with the inclined surface angle of the silicon plasma distribution disk blank. The polishing head pressure is 10-15KG, the polishing head speed is 1500-2000 rpm, the turntable speed is 80-100 rpm, and the polishing time is 0.3-0.6H.
[0038] Preferably, when polishing the surfaces of the front and back of the silicon plasma distribution disk blank, the X-axis reciprocating polishing is performed, the polishing spindle angle is 1.5-1.9°, the polishing head pressure is 15-20KG, the polishing head speed is 1500-2000 rpm, the reciprocating polishing feed speed is 15-25 mm / min, the turntable speed is 80-100 rpm, and the polishing time is 0.5-0.8 hours.
[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0040] The silicon plasma shunt disk processing method of the present invention first processes the front and back features of the silicon plasma shunt disk blank, then performs double-sided LAP grinding to remove the tool marks generated during processing, making the appearance of the upper and lower surfaces and the small hole surface of the silicon plasma shunt disk uniform and consistent, thereby reducing the subsequent polishing time and reducing the roughness of the subsequent polished surface. Finally, after etching and polishing, the roughness of the polished surface of the silicon plasma shunt disk is lower than Ra0.05. Attached Figure Description
[0041] Figure 1 This is a schematic diagram of silicon components used for chip etching.
[0042] Figure 2 This is a schematic diagram of the front structure of the silicon plasma distribution disk.
[0043] Figure 3 This is a schematic diagram of the reverse structure of the silicon plasma distribution disk.
[0044] Figure 4 This is a process flow diagram for the silicon plasma distribution disk.
[0045] In the diagram: upper surface 1, lower surface 2, and small hole surface 3. Detailed Implementation
[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0047] In the description of this invention, it should be understood that the terms "upper", "middle", "outer", "inner", "lower", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.
[0048] This invention provides a method for processing a silicon plasma distribution disk, comprising the following steps:
[0049] S1. Perform planar grinding on the silicon plasma distribution disk blank to grind the thickness of the silicon plasma distribution disk blank to the final product thickness +1-2mm, the parallelism to 0.09-0.15mm, and the flatness to 0.05-0.11mm.
[0050] S2. Machining positioning holes, small holes and other features on the silicon plasma distribution disk blank;
[0051] S3. Turn the silicon plasma distribution disk blank over and process the reverse side features;
[0052] S4. Perform double-sided LAP grinding on the silicon plasma distribution disk blank after feature processing.
[0053] S5. Use mixed acid to etch the polished silicon plasma distribution disk blank.
[0054] S6. Polish the etched silicon plasma distribution disk blank using a polishing machine.
[0055] The silicon plasma shunt disk processing method of the present invention first processes the front and back features of the silicon plasma shunt disk blank, then performs double-sided LAP grinding to remove the tool marks generated during processing, making the appearance of the upper and lower surfaces and the small hole surface of the silicon plasma shunt disk uniform and consistent, thereby reducing the subsequent polishing time and reducing the roughness of the subsequent polished surface. Finally, after etching and polishing, the roughness of the polished surface of the silicon plasma shunt disk is lower than Ra0.05.
[0056] In the specific implementation process, the following steps are used to process positioning holes, small holes and other features on the silicon plasma distribution disk blank:
[0057] S21. Bonding onto the machine: Bond the silicon plasma distribution disk blank to the quartz plate, and place the bonded quartz plate and the silicon plasma distribution disk blank on the machine tool work platform and clamp them.
[0058] In the specific implementation process, the following steps are used to bond the silicon plasma distribution disk blank to the quartz plate:
[0059] S211. A heating platform is used to heat the silicon plasma distribution disk blank and the quartz plate;
[0060] S212. After heating to 120℃, the silicon plasma distribution disk blank is bonded to the quartz plate using yellow wax. After bonding, the surface of the silicon plasma distribution disk blank is pressed and rotated clockwise to squeeze out air bubbles between the bonding surface of the silicon plasma distribution disk and the quartz plate, ensuring a tight bond. After bonding, the quartz plate and the silicon plasma distribution disk blank are placed on the machine tool work platform and leveled using a dial indicator, ensuring that the flatness of the quartz plate surface is within 0.03mm. Then, they are clamped. Finally, the silicon plasma distribution disk blank is rounded using a dial indicator to determine the machining origin, and the tool height parameters are confirmed using a tool setting block to ensure the accuracy and machining effect of subsequent processes. The use of yellow stone wax for bonding is advantageous because it does not cause metal contamination. Furthermore, if a suction cup is used to fix the silicon plasma distribution plate, it will leave marks on the product surface and requires a high degree of flatness from the suction cup. Using yellow stone wax for bonding, however, will not leave marks on the product surface. In addition, when the silicon plasma distribution plate is placed on the machine tool work platform, the surface can be leveled to achieve a low level of flatness and parallelism for the silicon plasma distribution plate.
[0061] S22. Machining the positioning hole: Use a 1-2mm diamond drill bit for pre-drilling, with a pre-drilling depth of 0.7-0.9mm, a tool speed of 10000-12000 rpm, a drilling feed rate of 0.15-0.25mm, a downward drilling feed rate of 10-20mm / min, and a retraction feed rate of 3000mm / min. After each downward stroke, retract the tool by 0.15-0.3mm. (The remaining text appears to be incomplete and requires further context.) Figure 2 As shown, the holes on surface 3 are small holes. The diameter of the small holes in a silicon plasma distribution disk is relatively small, generally between 0.2-0.6 mm. Drilling directly with a small-hole drill bit can easily lead to tool breakage. Therefore, a 1-2 mm diamond drill bit is used for pre-drilling to ensure that the drill bit will not vibrate and break during the actual drilling. Furthermore, machining the positioning holes creates a chamfer on the surface of the small holes. During use, when the etching gas flows through the silicon plasma distribution disk, the small hole area is easily etched. If the small hole has straight edges, the etching gas can easily wash away surrounding debris and slag, making it difficult to remove and resulting in faster wear. The chamfer on the surface of the small holes through the positioning holes facilitates chip removal and cooling of the tool, reducing wear.
[0062] S23. Machining Small Holes: Small holes are machined using diamond drill bits. The hole depth is 0.4-0.6 mm from the bottom surface of the silicon plasma distribution disk blank. The tool speed is 20,000-22,000 rpm. The initial drilling feed is 0.15-0.2 mm. After each drilling stroke, the drilling feed is reduced by 0.003 mm until it reaches 0.05 mm. The drilling feed is maintained at 0.05 mm until the hole is finished. The downward drilling feed rate is 5-10 mm / min, and the lift-off feed rate is 3000 mm / min. After each downward stroke, the tool is lifted by 0.3-0.5 mm. On average, about 500-1000 small holes are machined for one silicon plasma distribution disk. The lifespan of a small hole diamond drill bit is about 2000 holes. The average hole depth is 5-12mm. Before machining, turn on the center coolant outlet of the tool holder. The center coolant outlet has a higher cutting fluid pressure, which is effective in cooling the tool and removing silicon chips during machining. The tool speed is set to 20,000-22,000 rpm. The higher speed ensures the tool's drilling ability and reduces the risk of tool breakage. The drilling feed rate is initially set to 0.15-0.2mm, and then reduced by 0.003mm with each drilling pass, until it reaches 0.05mm, and this feed rate is used until the hole is finished. The drilling feed rate is gradually reduced because as the tool drills deeper, chip removal becomes more difficult and the tool temperature rises, eventually leading to tool breakage. Gradually reducing the feed rate not only ensures consistent hole quality but also reduces the risk of tool breakage. The drilling feed rate is set to 5-10 mm / min, and the tool lift-off feed rate is set to 3000 mm / min. After each downward stroke, the tool is lifted 0.3-0.5 mm to facilitate chip removal and cooling. The hole depth is set to 0.5 mm from the bottom surface of the product. Drilling through the bottom will cause chipping at the exit point, and since there is often yellow paraffin wax on the bottom of the product, contact with the drill bit will affect the tool's grinding ability, leading to tool breakage. Furthermore, using these parameters for machining small holes results in a thinner fracture layer inside the hole, which can be thoroughly removed with etching fluid, resulting in high machining efficiency and reducing the risk of tool breakage in small holes.
[0063] S24. Machining the waist hole characteristics: The waist hole is machined using a 250-350 grit diamond tool with a metal matrix, 2mm smaller in diameter than the waist hole diameter. The feed rate is 400-600mm / min, with a helical cutting approach and a cutting step of 0.03-0.06mm / revolution. The tool speed is 7500-8500 rpm. The waist hole is not machined through; a 0.3-0.5mm allowance is left at the bottom to prevent through-hole chipping. (Example: ...) Figure 2 As shown, the hole on the upper surface 1 is the waist hole, which is used to fix the screw, and the silicon plasma distribution plate is fixed to the equipment by the screw.
[0064] S25. Machining the inclined surface features: The inclined surface is machined using a 60-80mm diameter, 450-550 mesh resin-based diamond tool. The machining feed rate is 1000-1200mm / min, the downward cutting is done with a helical cutter, the downward cutting step is 0.02-0.04mm / revolution, and the tool speed is 3500-4500 rpm.
[0065] S26. Groove Machining Features: The groove is machined using a 30-60mm diameter, 150-250 mesh metal-based diamond abrasive tool. The feed rate is 800-1000mm / min, and the downward cut is made using a spiral cutter with a step distance of 0.03-0.06mm / revolution. The tool speed is 5500-6500 rpm. The edges are chamfered to prevent chipping or gaps in subsequent processes.
[0066] Metal-based diamond tools are made from a mixture of diamond and metal materials. They are highly rigid, but produce products with a rougher surface and more pronounced tool marks. Resin-based diamond tools, on the other hand, are made from a mixture of resin and diamond. They are less rigid, produce products with a smoother surface, a higher grit, fewer tool marks, and are easier to polish to a mirror finish. Grooves are used to install screws and do not significantly affect elasticity; therefore, metal-based diamond tools are sufficient for machining them. However, beveled features allow direct passage of etching gas. Lower surface roughness results in a higher finish, less etching by the gas, and a longer lifespan. Therefore, resin-based diamond tools are used for beveled features.
[0067] S27. The surface of the silicon plasma distribution disk blank and the small hole surface are finished. Specifically, a rough finish of 0.4 mm is achieved using a 270-grit metal-based diamond abrasive tool, followed by a semi-finish finish of 0.05 mm using a 500-grit resin-based diamond abrasive tool, and finally a finish finish of 0.05 mm using a 2200-grit resin-based diamond abrasive tool. Because the mechanical damage layer thickness after grinding with different grit tools is greater, lower grit tools result in a larger mechanical damage layer and higher roughness. Finally, finishing with a 2200-grit tool minimizes the mechanical damage layer. Furthermore, a broken layer and chipped edges are generated at the drilling inlet in the previous process; a 0.5 mm finish can remove these defects, maintaining the quality of the hole edge.
[0068] S28. Machining the outer diameter: The outer diameter is machined using a 30-60mm diameter, 150-250 mesh metal matrix diamond abrasive tool. The machining feed rate is 1000-1200mm / min, the downward cut is made using a spiral cutter, the downward cut step is 0.03-0.06mm / turn, the tool speed is 4500-6500 rpm, and the outer diameter is chamfered to prevent bumps during transportation and to prevent chipping or gaps in subsequent processes.
[0069] In some embodiments, after the positioning holes, pinholes and other features are processed, the silicon plasma splitter blank and the quartz plate are removed from the machine, and the silicon plasma splitter blank and the quartz plate are heated and dewaxed using a heating platform, thereby separating the silicon plasma splitter blank from the quartz plate.
[0070] In the specific implementation process, the silicon plasma distribution disk blank is flipped over, and the reverse side features are processed using the following steps:
[0071] S31. Bonding and Mounting: Turn the silicon plasma distribution plate blank over and bond the machined surface of the silicon plasma distribution plate blank from step S2 to the quartz plate. Place the bonded quartz plate and the silicon plasma distribution plate blank on the machine tool work platform and clamp them. Specifically, after turning the silicon plasma distribution plate blank over... Figure 3 As shown, the front side of the silicon plasma distribution disk blank is shown. Figure 2 The face shown is bonded to the quartz plate, thereby machining the reverse side features of the silicon plasma distribution disk blank. Specifically, the front side of the silicon plasma distribution disk blank and the quartz plate are heated to 120°C using a heating platform. Yellow wax is melted and then used for bonding. After bonding, the silicon plasma distribution disk blank is pressed and rotated clockwise to expel air bubbles between the bonding surface of the silicon plasma distribution disk blank and the quartz plate, ensuring a tight bond. After bonding, the quartz plate is placed on the machine tool work platform and leveled using a dial indicator, ensuring the surface flatness of the quartz plate is within 0.03mm. It is then clamped. Finally, the silicon plasma distribution disk blank is rounded using a dial indicator to determine the machining origin, and the tool height parameters are confirmed using a tool setting block to ensure the accuracy and quality of the machining process.
[0072] S32. Polish the surface: Use a 250-300 mesh metal matrix diamond tool to rough polish the silicon plasma distribution disk blank by 0.4 mm, so that the waist hole that was not processed through in step S24 is exposed, and the waist hole becomes a through hole after polishing.
[0073] S33. Alignment: Alignment is performed through the waist holes and through holes to ensure that the placement direction and position of the silicon plasma distribution plate blank are consistent with those in step S2. Specifically, the waist holes and through holes are aligned using a dial indicator to find that their positions are exactly the same as those of the holes in step S2, so that the holes on the front and back sides are aligned.
[0074] S34. Machining the Countersunk Hole: The countersunk hole is machined using a 250-350 grit diamond tool with a diameter 2mm smaller than the countersunk hole diameter. The feed rate is 400-600 mm / min, using a helical cutter with a step distance of 0.03-0.06 mm / revolution. The tool speed is 7500-8500 rpm. The edges of the countersunk hole are chamfered to prevent chipping in subsequent processes. For example... Figure 3 As shown, the hole on the lower surface 2 is a countersunk hole, used to place the screw cap.
[0075] S35. Groove characteristics: Use a 30-60mm diameter, 150-250 mesh metal-based diamond abrasive tool for machining. The feed rate is 800-1000mm / min. The downward cut is made using a spiral cutter with a step distance of 0.03-0.06mm / turn. The tool speed is 5500-6500 rpm. The edges are chamfered to prevent chipping or gaps in subsequent processes.
[0076] S36. The surface of the silicon plasma distribution disk blank and the small hole surface are finished. Specifically, a rough finish of 0.4 mm is achieved using a 270-grit metal-based diamond abrasive tool, followed by a semi-finish finish of 0.05 mm using a 500-grit resin-based diamond abrasive tool, and finally a finish finish of 0.05 mm using a 2200-grit resin-based diamond abrasive tool. Because the mechanical damage layer thickness after grinding with different grit tools is greater, lower grit tools result in a larger mechanical damage layer and higher roughness. Finally, finishing with a 2200-grit tool minimizes the mechanical damage layer. Furthermore, a fracture layer and chipped edges are generated at the drilling inlet in the previous process; a 0.5 mm finish can remove these defects, maintaining the quality of the hole edge.
[0077] S37. Machining the outer diameter chamfer: Use a 30-60mm diameter, 150-250 mesh metal matrix diamond tool to machine the outer diameter chamfer. The machining feed rate is 1000-1200mm / min. The downward cut is made using a spiral cutter with a cutting step of 0.03-0.06mm / turn. The tool speed is 4500-6500 rpm. The outer diameter is chamfered to prevent chipping or gaps in subsequent processes.
[0078] After the reverse side features are processed, the silicon plasma splitter blank and the quartz plate are removed from the machine, and the silicon plasma splitter blank and the quartz plate are heated and dewaxed using a heating platform, thereby separating the silicon plasma splitter blank from the quartz plate.
[0079] In the specific implementation process, the double-sided LAP grinding of the silicon plasma distribution disk blank after feature processing adopts the following steps: The upper and lower surfaces and the surface of the small holes of the silicon plasma distribution disk blank after feature processing are ground using LAP 1500-2000 mesh abrasive powder. To further remove the broken layer on the surface of the silicon plasma distribution disk product and reduce roughness to improve smoothness, etching and polishing are required. However, due to the numerous tool marks on the product surface after machining, subsequent polishing is quite difficult, the amount of material removed by polishing is small, and the tool marks cannot be effectively removed, increasing polishing time and leading to more scratches and stains after polishing. Therefore, the upper and lower surfaces and the surface of the small holes are first ground with LAP 1500-2000 mesh abrasive powder to remove the tool marks and the damaged layer after tool processing, making the appearance of the upper and lower surfaces and the surface of the small holes uniform, thereby reducing the subsequent polishing time and lowering the roughness of the polished surface. After grinding with fine-mesh sand, dimensional inspection is required to ensure the product's dimensions meet the requirements of subsequent processes. The product is then promptly boiled and ultrasonically cleaned; otherwise, the dried fine sand may clog the pores, rendering the product unusable. Dimensional measurements include checking basic dimensions, roughness, flatness, and parallelism.
[0080] Double-sided LAP grinding involves applying abrasive powder to both the upper and lower surfaces of the silicon plasma distribution disk within a LAP machine. This removes the tool marks left by machining, resulting in a uniform color on the polished surface. Without double-sided LAP grinding, direct polishing after machining requires a prolonged polishing time to remove the tool marks. Excessive polishing time can lead to the corrosive effect of the polishing fluid, leaving marks on the polished side. Therefore, performing double-sided LAP grinding first shortens the subsequent polishing time and improves the polishing effect.
[0081] In the specific implementation process, the etching of the polished silicon plasma distribution disk blank using mixed acid involves the following steps: the etching depth of the small holes in the silicon plasma distribution disk blank is 0.02-0.04 mm, and the etching depth of the upper and lower surfaces is 0.01 mm per side. Specifically, the etching process uses mixed acid etching, which is composed of HF (49%): HNO3 (70%): CH3COOH (99%) in a ratio of 2:5:3. The etching time for a single product is 25-35 seconds to remove mechanical damage to the product surface and the inner wall of the micropores of the plasma distribution disk.
[0082] In the specific implementation process, the polishing of the etched silicon plasma distribution disk blank using a polishing machine involves the following steps: the polishing machine sequentially polishes the small hole surfaces, bevels, and surfaces on both sides of the silicon plasma distribution disk blank, maintaining a consistent polishing process on both sides. Some existing silicon plasma distribution disk processing technologies on the market can only achieve single-sided polishing, not double-sided polishing. Some processes using double-sided polishing machines can achieve double-sided polishing, but can only polish the larger surfaces of both sides, failing to polish bevels or recessed surfaces. This invention uses a four-axis polishing machine with a rotary table to perform double-sided polishing of the etched silicon plasma distribution disk blank, and can also polish bevels and grooves through surface grinding, improving the polishing effect.
[0083] When polishing the small hole surfaces on both sides of the silicon plasma distribution disk blank, the X-axis reciprocating polishing is performed, the polishing spindle angle is 1.5-1.9°, the polishing head pressure is 15-20KG, the polishing head speed is 1500-2000 rpm, the reciprocating polishing feed speed is 15-25mm / min, the turntable speed is 80-100 rpm, and the polishing time is 1-1.2H.
[0084] When polishing the beveled surfaces on both sides of the silicon plasma distribution disk blank, a fixed-angle, fixed-point polishing method is used. The polishing spindle angle is consistent with the bevel angle of the silicon plasma distribution disk blank. The polishing head pressure is 10-15KG, the polishing head speed is 1500-2000 rpm, the turntable speed is 80-100 rpm, and the polishing time is 0.3-0.6 hours.
[0085] When polishing the surfaces of the front and back of the silicon plasma distribution disk blank, the X-axis reciprocating polishing is performed with a polishing spindle angle of 1.5-1.9°, a polishing head pressure of 15-20 kg, a polishing head rotation speed of 1500-2000 rpm, a reciprocating polishing feed speed of 15-25 mm / min, a turntable rotation speed of 80-100 rpm, and a polishing time of 0.5-0.8 hours. The surfaces of the front and back of the silicon plasma distribution disk blank include, for example: Figure 2 The upper surface 1 of the front, as Figure 3 The lower surface 2 of the front side is polished, and the upper surface 1 and the lower surface 2 are polished respectively. By polishing the surface of the silicon plasma distribution disk, the surface of the small hole and the inclined surface with corresponding process parameters, the polishing time is shorter than the traditional polishing time, the surface appearance after polishing is better than that of traditional polishing, and the roughness of the polished surface can reach below Ra0.05.
[0086] In some embodiments, since the silicon plasma distribution disk requires double-sided polishing, if a suction cup is used to hold it during the polishing of the second side, air suction grooves will appear on the polished surface of the first side. If side clamping is used for fixation, polishing waste liquid will flow into the bottom, causing dirt and scratches. Therefore, this invention uses yellow stone wax to bond the silicon plasma distribution disk to a tooling with good flatness for polishing. Furthermore, to prevent yellow stone wax from contaminating or clogging the micropores, yellow stone wax is applied to the edges of the silicon plasma distribution disk for bonding, but not to the central micropore area. During the polishing process, the polishing friction generates heat, and the high temperature will melt the yellow stone wax, causing the silicon plasma distribution disk to detach. Therefore, polishing needs to be paused every 10 minutes, and the silicon plasma distribution disk and tooling should be cooled with cold water.
[0087] In some implementations, the entire fabrication process of the silicon plasma distribution disk is as follows: Figure 4 As shown, in the single crystal pulling process, the main focus is on designing the thermal field structure and widening the crystal growth process window to control slip defects and resistivity parameters, thereby pulling single crystals without slip dislocations. The resistivity is generally required to be 1~4 ohm·cm to meet the requirements for manufacturing silicon components for integrated circuit etching machines. The mechanical forming of the silicon plasma shunt disk blank mainly involves mechanically processing the silicon crystal rod through cutting, rolling, and multi-wire cutting to process it into the required circular shape for the silicon plasma shunt disk. Then, surface grinding is used to remove surface cutting marks caused by wire cutting and reduce surface mechanical damage and microcracks, grinding the blank thickness to the final product thickness +1-2mm, parallelism to 0.09-0.15mm, and flatness to 0.05-0.11mm. Next, MC machining is used to process positioning holes, small holes, and other screw holes. After processing, the silicon plasma shunt disk is flipped over, and MC machining is used to process the reverse side features. After all features of the silicon plasma distribution disk blank are processed, the blank undergoes double-sided LAP grinding. The silicon electrode is placed on a double-sided grinding machine, and by applying pressure and rotation speed, and introducing grinding fluid, the LAP 1500-2000 mesh grinding powder slides and rubs against the surface of the silicon plasma distribution disk, ensuring effective and thorough grinding. After grinding, dimensional inspection and boiling cleaning are performed to effectively remove impurities from the surface of the silicon plasma distribution disk. Following etching, polishing, and cleaning processes, final inspection and packaging are carried out. Each processing step includes a cleaning process to remove oil and silicon slag residue from machining.
[0088] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the invention.
Claims
1. A method for processing a silicon plasma distribution disk, characterized in that, Includes the following steps: S1. Perform planar grinding on the silicon plasma distribution disk blank to grind the thickness of the silicon plasma distribution disk blank to the final product thickness +1-2mm, the parallelism to 0.09-0.15mm, and the flatness to 0.05-0.11mm. S2. Machining positioning holes, small holes and other features on the silicon plasma distribution disk blank; S3. Turn the silicon plasma distribution disk blank over and process the reverse side features; S4. Perform double-sided LAP grinding on the silicon plasma distribution disk blank after feature processing. S5. Use mixed acid to etch the polished silicon plasma distribution disk blank. S6. Polish the etched silicon plasma distribution disk blank using a polishing machine; In step S2, the following steps are used to machine positioning holes, small holes, and other features on the silicon plasma distribution disk blank: S21. Bonding onto the machine: Bond the silicon plasma distribution disk blank to the quartz plate, and place the bonded quartz plate and the silicon plasma distribution disk blank on the machine tool work platform and clamp them. S22. Machining positioning holes: Use a 1-2mm diamond drill bit to pre-drill holes to a depth of 0.7-0.9mm; S23. Machining small holes: Use a diamond drill bit to machine small holes, with a hole depth of 0.4-0.6 mm from the bottom surface of the silicon plasma distribution disk blank. S24. Machining the waist hole features: The waist hole is machined using a 250-350 mesh metal matrix diamond tool with a diameter 2mm smaller than the diameter of the waist hole, leaving a 0.3-0.5mm allowance at the bottom of the waist hole; S25. Machining the beveled surface features: The beveled surface is machined using a 60-80mm diameter, 450-550 mesh resin-based diamond abrasive tool. S26. Groove characteristics: The groove is machined using a 30-60mm diameter, 150-250 mesh metal-based diamond tool, and the edges are chamfered. S27. Polish the surface of the silicon plasma distribution disk blank and the surface of the small holes. S28. Machining the outer diameter: Use a 30-60mm diameter, 150-250 mesh metal matrix diamond tool to machine the outer diameter, and perform chamfering on the outer diameter.
2. The method of claim 1, wherein In step S21, the silicon plasma distribution disk blank is bonded to the quartz plate using the following steps: S211. A heating platform is used to heat the silicon plasma distribution disk blank and the quartz plate; S212. After heating to 120℃, the silicon plasma distribution disk blank is bonded to the quartz plate using yellow stone wax.
3. The method of claim 2, wherein the silicon plasma diverter plate is formed by a process comprising: In step S3, the silicon plasma distribution disk blank is flipped over, and the reverse side features are processed using the following steps: S31, Bonding onto the machine: Turn the silicon plasma distribution disk blank over and bond the surface of the silicon plasma distribution disk blank processed in step S2 to the quartz plate. Place the bonded quartz plate and the silicon plasma distribution disk blank on the machine tool work platform and clamp them. S32. Polish the surface: Use a 250-300 mesh metal matrix diamond tool to rough polish the silicon plasma distribution disk blank by 0.4 mm, so that the waist hole that was not processed through in step S24 is exposed, and the waist hole becomes a through hole after polishing. S33. Alignment: Alignment is performed through the waist hole to ensure that the placement direction and position of the silicon plasma distribution plate blank are consistent with those in step S2. S34. Machining the countersunk hole: Use a 250-350 mesh metal matrix diamond tool with a diameter 2mm smaller than the countersunk hole diameter to machine the countersunk hole, and chamfer the edges of the countersunk hole. S35. Groove features: The groove is machined using a 30-60mm diameter, 150-250 mesh metal-based diamond abrasive tool, and the edges are chamfered. S36. Polish the surface of the silicon plasma distribution disk blank and the small hole surface; S37. Machining outer diameter chamfer: Use a 30-60mm diameter, 150-250 mesh metal matrix diamond tool to machine the outer diameter chamfer.
4. The method of claim 1, wherein the silicon plasma diverter plate is formed by a process comprising: In step S4, the double-sided LAP grinding of the silicon plasma distribution disk blank after feature processing is carried out using the following steps: LAP 1500-2000 mesh abrasive powder is used to grind the upper and lower surfaces and the surface of the small holes of the silicon plasma distribution disk blank after feature processing.
5. The method of claim 1, wherein In step S5, when the silicon plasma distribution disk blank is etched with mixed acid, the etching amount of the small holes of the silicon plasma distribution disk blank is 0.02-0.04 mm, and the etching amount of the upper and lower surfaces is 0.01 mm on each side.
6. The method of claim 1, wherein In step S6, the silicon plasma distribution disk blank after etching is polished using a polishing machine. The following steps are performed: the small hole surface, the bevel surface and the surface on both sides of the silicon plasma distribution disk blank are polished sequentially using a polishing machine.
7. The method of claim 6, wherein the silicon plasma diverter plate is formed by a process comprising: When polishing the small hole surfaces on both sides of the silicon plasma distribution disk blank, the X-axis reciprocating polishing is performed, the polishing spindle angle is 1.5-1.9°, the polishing head pressure is 15-20KG, the polishing head speed is 1500-2000 rpm, the reciprocating polishing feed speed is 15-25mm / min, the turntable speed is 80-100 rpm, and the polishing time is 1-1.2H.
8. The method for processing a silicon plasma distribution disk according to claim 7, characterized in that, When polishing the beveled surfaces on both sides of the silicon plasma distribution disk blank, a fixed-angle, fixed-point polishing method is used. The polishing spindle angle is consistent with the bevel angle of the silicon plasma distribution disk blank. The polishing head pressure is 10-15KG, the polishing head speed is 1500-2000 rpm, the turntable speed is 80-100 rpm, and the polishing time is 0.3-0.6 hours.
9. The method for processing a silicon plasma distribution disk according to claim 8, characterized in that, When polishing the surfaces of the front and back of the silicon plasma distribution disk blank, the X-axis reciprocating polishing is performed, the polishing spindle angle is 1.5-1.9°, the polishing head pressure is 15-20KG, the polishing head speed is 1500-2000 rpm, the reciprocating polishing feed speed is 15-25 mm / min, the turntable speed is 80-100 rpm, and the polishing time is 0.5-0.8 hours.