Wafer polishing device and polishing process
By using a heatable loading disk and a flexible polishing film in sapphire wafer processing, combined with temperature control and solid-phase chemical reaction, the problems of environmental pollution and high cost in traditional methods are solved, and the efficient and low-damage sapphire crystals are achieved. Circular polishing process.
Patent Information
- Application Number
- CN202411703748.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-26
- Publication Date
- 2025-01-14
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The traditional copper casting and CMP methods have problems such as environmental pollution, high processing costs and low efficiency in sapphire wafer processing, which affects the mass production and yield of sapphire wafers.
Using a heatable load disk and a temperature control system combined with a flexible polishing film, the processing interface temperature of 50°C and the mixed W3 diamond hard abrasive and silica active soft abrasive are accelerated through solid-phase chemical reactions to reduce mechanical removal damage.
It improves material removal rate, reduces processing damage, improves surface flatness and yield, and realizes an efficient and low-cost sapphire wafer polishing process.
Smart Images
Figure CN119304762A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a wafer polishing device and a polishing process. Background Art
[0002] At present, the mass production process of sapphire wafers mainly includes multiple processes such as slicing, grinding, and polishing. Grinding and polishing belong to the precision processing process of sapphire wafers. They are important methods for wafers to obtain ultra-smooth and damage-free surfaces. The processing cost accounts for about 80% of the entire sapphire wafer processing process. Among them, the grinding process includes two processes: double-sided rough grinding and single-sided fine grinding. Double-sided rough grinding is used to quickly flatten the surface undulations of the wafer and reduce the surface roughness. Single-sided fine grinding is mostly used to remove the surface metamorphic layer remaining from double-sided rough grinding and further reduce the surface roughness. Polishing is a necessary means to obtain high surface flatness and surface integrity. It is usually used as the last step in sapphire wafer processing to obtain ultra-smooth and damage-free processing quality on the wafer surface, such as copper polishing and chemical mechanical polishing (CMP for short). Copper polishing is the most widely used single-sided polishing method in the mass production process of pre-cut wafers. It can quickly reduce the surface roughness of the wafer and remove the material metamorphic layer. However, the inherent defects of traditional copper polishing and CMP methods, such as environmental pollution, high processing cost and low efficiency, have had a serious impact on the mass production and yield of sapphire wafers.
[0003] Green manufacturing is the fundamental path to achieve sustainable development, and it is also an inevitable choice to follow the trend of technological progress and promote the optimization and upgrading of economic structure. Sapphire materials have high hardness, brittleness and corrosion resistance. How to achieve green manufacturing and process mass production of sapphire wafers has become a hot and difficult research topic. Therefore, in-depth research on green ultra-precision processing technology of sapphire wafers and the development of new green processing methods are of great significance to obtain high-efficiency and high-quality wafer materials. Summary of the invention
[0004] The object of the present invention is to provide a wafer polishing device and a polishing process to solve the problems raised in the above background technology.
[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a wafer polishing device and a polishing process, comprising a heatable carrier plate, a heating element is embedded in the plate and a temperature sensor is fixed thereto, a groove for placing a sapphire wafer is provided at the bottom, a heat insulation plate and a machine tool spindle fixture are installed on the upper side, a power line of the heating element and a compensation line of the temperature sensor are connected to an external temperature controller through a conductive slip ring, the conductive slip ring is fixed on the machine tool spindle fixture, the conductive slip ring is fixed to the machine tool spindle through a slip ring fixing bracket, the slip ring fixing bracket is made of metal, ceramic or plastic material with high strength and good wear resistance, the heating element comprises a W-shaped heating element shell and an internal heating wire.
[0006] Preferably, the device works in the following manner: (1) The sapphire wafer to be processed is placed in the groove below the heatable carrier plate, the heating element is embedded in the carrier plate, and the power line of the heating element is connected to the power line of the conductive slip ring; (2) Use bolts to fix the heated loading plate, heat shield and machine tool spindle fixture, and the conductive slip ring One end is fixed on the machine tool spindle fixture, and the other end is fixed on the machine tool spindle through a slip ring fixing bracket; (3) The temperature sensor is fixed inside the heated loading plate and connected to the conductive slip ring through a compensation wire. The other end of the conductive slip ring is connected to an external temperature controller. (4) According to the processing parameters, the temperature is set by the temperature controller, and the temperature controller receives the temperature signal of the temperature sensor; when the temperature of the heatable carrier plate is lower than the preset temperature, the power supply is automatically turned on, and when the preset temperature is reached, an alarm is automatically sounded and the power supply is stopped, thereby realizing the temperature controllable of the heatable carrier plate, and the temperature of the processing interface is controlled at 50℃±2℃.
[0007] Preferably, the polishing liquid used in the device is deionized water, and the polishing film is a mixture of W3 diamond hard abrasive and silica active soft abrasive at the same concentration of 2.5wt.%.
[0008] Preferably, the preparation method of the silica active soft abrasive is as follows: 100 ml of deionized water, 100 ml of anhydrous ethanol and 12, l of ammonia solution are mixed and placed in a magnetic stirring water bath, stirred at a constant temperature of 30°C for 10 minutes, and then 200 ml of an ethanol solution containing 18 ml of ethyl orthosilicate is added to the mixed solution for reaction for 18 hours and aging for 6 hours. After 3 centrifugal treatments, each at a speed of 8000 rpm / min for 10 minutes, a mixed solution containing a white solid precipitate can be obtained. The white solid in the mixed solution is dried at a constant temperature of 60°C for 12 hours, and ground to finally obtain uniformly dispersed white abrasive particles, namely, silica active soft abrasive.
[0009] Compared with the prior art, the invention has the following beneficial effects: at room temperature, the material removal rate of the mixed abrasive is 30% and 53% higher than that of the single diamond and silicon dioxide abrasives. When the processing interface temperature is 50°C, a solid phase chemical reaction occurs between the sapphire and the active abrasive to generate Al 2 O 3 ·Si0 2 The material removal rate is accelerated, and the highest material removal rate is 101% higher than that at room temperature. The processed surface is smoother and less damaged. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 It is a schematic diagram of the structure of the device of the present invention; Figure 2 This is an enlarged view of point A in the figure; Figure 3 Exploded view of the heated loading tray.
[0011] In the figure: 1 temperature controller, 2 slip ring fixing bracket, 3 power line, 4 conductive slip ring, 5, 6 heated loading plate, 7 machine tool spindle, 8 temperature sensor compensation line, 9 temperature sensor, 10 heating element, 101 heating wire, 102 heating element housing. DETAILED DESCRIPTION
[0012] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0013] See also Figure 1-3 The present invention provides a technical solution: a wafer polishing device and a polishing process, comprising a heatable carrier plate 6 made of a high thermal conductivity material, a heating element 10 embedded in the plate and a temperature sensor 9 fixed thereon, a groove for placing a sapphire wafer at the bottom, a heat insulation board 5 and a machine tool spindle fixture installed at the top, wherein the machine tool spindle fixture is a stainless steel fixture, a power line 3 of the heating element 10 and a temperature sensor compensation line 8 are connected to an external temperature controller 1 through a conductive slip ring 4, the conductive slip ring 4 is fixed on the machine tool spindle fixture, the conductive slip ring 4 is fixed to the machine tool spindle 7 through a slip ring fixing bracket 2, the slip ring fixing bracket 2 is made of a metal, ceramic or plastic material with high strength and good wear resistance, the heating element 10 comprises a W-shaped heating element housing 102 and an internal heating wire 101, and the device is operated as follows: (1) Place the sapphire wafer to be processed in the groove below the heated carrier plate. The component is embedded in the loading plate, and the power line of the heating element is connected to the power line of the conductive slip ring; (2) Use bolts to fix the heated loading plate, heat shield and machine tool spindle fixture, and the conductive slip ring One end is fixed on the machine tool spindle fixture, and the other end is fixed on the machine tool spindle through a slip ring fixing bracket; (3) The temperature sensor is fixed inside the heated loading plate and connected to the conductive slip ring through a compensation wire. The other end of the conductive slip ring is connected to an external temperature controller. (4) The temperature is set by a temperature controller according to the processing parameters, and the temperature controller receives the temperature signal of the temperature sensor; when the temperature of the heatable carrier plate is lower than the preset temperature, the power supply is automatically turned on, and when the preset temperature is reached, an alarm is automatically sounded and the power supply is stopped, thereby realizing the temperature controllable of the heatable carrier plate.
[0014] The processing parameters are: the temperature of the processing interface is controlled at 50℃±2℃.
[0015] The present invention designs a semi-solidified flexible polishing film, which is mixed with W3 diamond hard abrasive and silicon dioxide active soft abrasive at the same concentration of 2.5wt.%, wherein the preparation method of the silicon dioxide active soft abrasive is as follows: 100 ml of deionized water, 100 ml of anhydrous ethanol and 12, l of ammonia solution were mixed and placed in a magnetic stirring water bath, stirred at a constant temperature of 30°C for 10 min, and then 200 ml of ethanol solution containing 18 ml of ethyl orthosilicate was added to the mixed solution for reaction for 18 h and aging for 6 h. After 3 centrifugal treatments, each at a speed of 8000 rpm / min for 10 min, a mixed solution containing white solid precipitates was obtained. The white solid in the mixed solution was dried at a constant temperature of 60°C for 12 h, and ground to finally obtain uniformly dispersed white abrasive particles, namely, silica active soft abrasive.
[0016] When the elasticity and stiffness of the polishing film change, the displacement of the abrasive particles due to the force will change, resulting in changes in the depth of the abrasive engraving into the wafer and the surface roughness of the wafer. The simulation results show that the elastic characteristics of the flexible polishing film can promote the "sinking" trend of the abrasive particles, so that the abrasive particles evenly distributed in the polishing film are at the same height when rubbing and cutting sapphire, thereby reducing the mechanical damage caused by hard abrasives with excessive initial edge height.
[0017] At room temperature, the material removal rate of the mixed abrasive is 30% and 53% higher than that of single diamond and silica abrasives. When the processing interface temperature is 50°C, a solid-phase chemical reaction occurs between sapphire and the active abrasive to generate Al 2 O 3 ·Si0 2 The rate of (andalusite) removal is accelerated, and the material removal rate is increased by 101% at the highest compared with room temperature. The processed surface is smoother and less damaged. The sapphire wafer polishing process using the device of the present invention to assist the mixed abrasive can promote the synergistic effect of hard abrasive mechanical cutting and active abrasive chemical corrosion, achieve efficient material removal and improve surface processing quality, and provide an efficient method for the processing of sapphire wafers.
[0018] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A wafer polishing device and a polishing process, characterized in that: The device comprises a heatable loading plate, in which a heating element is embedded and a temperature sensor is fixed, a groove for placing a sapphire wafer is arranged at the bottom, a heat insulation plate and a machine tool spindle fixture are installed at the top, a power line of the heating element and a compensation line of the temperature sensor are connected to an external temperature controller through a conductive slip ring, the conductive slip ring is fixed on the machine tool spindle fixture, and the conductive slip ring is fixed to the machine tool spindle through a slip ring fixing bracket, the slip ring fixing bracket is made of metal, ceramic or plastic material with high strength and good wear resistance, and the heating element comprises a W-shaped heating element shell and an internal heating wire.
2. The wafer polishing device and polishing process according to claim 1, characterized in that: The working mode of the device is as follows: (1) The sapphire wafer to be processed is placed in the groove below the heatable carrier plate, the heating element is embedded in the carrier plate, and the power line of the heating element is connected to the power line of the conductive slip ring; (2) Use bolts to fix the heated loading plate, heat shield and machine tool spindle fixture, and the conductive slip ring One end is fixed on the machine tool spindle fixture, and the other end is fixed on the machine tool spindle through a slip ring fixing bracket; (3) The temperature sensor is fixed inside the heated loading plate and connected to the conductive slip ring through a compensation wire. The other end of the conductive slip ring is connected to an external temperature controller. (4) According to the processing parameters, the temperature is set by the temperature controller, and the temperature controller receives the temperature signal of the temperature sensor; when the temperature of the heatable carrier plate is lower than the preset temperature, the power supply is automatically turned on, and when the preset temperature is reached, an alarm is automatically sounded and the power supply is stopped, thereby realizing the temperature controllable of the heatable carrier plate, and the temperature of the processing interface is controlled at 50℃±2℃.
3. The wafer polishing device and polishing process according to claim 1, characterized in that: The polishing liquid used in the device is deionized water, and the polishing film is a mixture of W3 diamond hard abrasive and silicon dioxide active soft abrasive with the same concentration of 2.5wt.%.
4. The wafer polishing device and polishing process according to claim 1, characterized in that: The preparation method of silica active soft abrasive is as follows: 100 ml of deionized water, 100 ml of anhydrous ethanol and 12, l of ammonia solution are mixed and placed in a magnetic stirring water bath, and stirred at a constant temperature of 30°C for 10 minutes, and then 200 ml of ethanol solution containing 18 ml of ethyl orthosilicate is added to the mixed solution for reaction for 18 hours and aging for 6 hours. After 3 centrifugal treatments, each time at a speed of 8000 rpm / min, the mixed solution containing white solid precipitation can be obtained. The white solid in the mixed solution is dried at a constant temperature of 60°C for 12 hours, and ground to finally obtain uniformly dispersed white abrasive particles, namely silica active soft abrasive.