A polishing liquid in-situ observation device for polishing
By integrating a CCD camera, LED light source, and stirring device into the grinding machine, and combining it with a dark box design, the problem that existing devices cannot accurately reflect the flow state of the grinding fluid is solved, enabling accurate measurement of the flow rate and distribution of the grinding fluid, thus meeting the needs of high-precision wafer processing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- KUNMING UNIV OF SCI & TECH
- Filing Date
- 2025-08-23
- Publication Date
- 2026-08-04
AI Technical Summary
Existing flow field observation devices cannot accurately reflect the flow state of polishing slurry at the actual processing interface, and lack the ability to observe the uniformity of polishing slurry distribution on the polishing pad surface, thus failing to meet the requirements of high-precision wafer processing.
The CCD camera, LED light source, and observation components are integrated into the main body of the grinder. Combined with the dark box design, a uniform grinding slurry with tracer particles is provided through a stirring device. Images on the grinding pad are acquired in real time to observe the flow rate and distribution uniformity of the grinding slurry, reduce ambient light interference, and improve image clarity.
It enables accurate measurement of the flow rate and distribution of polishing slurry under actual processing conditions, provides a basis for evaluating polishing pad performance, and meets the optimization requirements of high-precision wafer processing.
Smart Images
Figure CN224587784U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an in-situ observation device for grinding fluid in grinding and polishing, belonging to the field of flow field observation. Background Technology
[0002] With the advancement of semiconductor material processing, achieving wafer surface planarization is a crucial step in ensuring device performance. Fixed Abrasive Chemical Mechanical Polishing (FA-CMP), based on Chemical Mechanical Polishing (CMP), is currently a key technology for achieving highly planar wafer surfaces. It works by subjecting the wafer to relative motion with a polishing pad under pressure and in the presence of a polishing slurry. The mechanical abrasion of nano-abrasives combined with the chemical corrosion of oxidants and catalysts peels away the wafer surface material layer by layer, achieving a highly planarized effect. This technology has been widely applied to the polishing of ultra-hard and brittle semiconductor materials such as sapphire and silicon carbide. The pattern and composition of the polishing pad affect the wafer removal efficiency. During wafer processing, the quality of the polishing pad can be assessed by observing the distribution and flow rate of the polishing slurry on the pad. With the development of the semiconductor industry, there are some existing flow field observation devices for grinding and polishing. For example, CN 222430410 U provides an ultra-precision polishing micro-flow field observation device. This device simulates the liquid flow velocity during wafer polishing by designing flow channels, adding tracer particles to the liquid, and using a CCD camera to observe the tracer particles in the flow channels. It can observe the flow velocity of the polishing liquid, and the liquid can be reused. The design method is ingenious. However, the above device is not based on real processing conditions (such as lack of actual conditions such as dynamic contact between wafer and polishing pad, pressure loading, etc.). The flow velocity data measured cannot reflect the flow state of polishing liquid at the actual processing interface, and the evaluation of polishing pad performance is biased. At the same time, the device lacks the ability to observe the uniformity of polishing liquid distribution on the polishing pad surface, and cannot meet the needs of high-precision wafer processing for polishing process parameter optimization. Summary of the Invention
[0003] This invention provides an in-situ observation device for grinding fluid in grinding and polishing. The device provides an observation platform for flow field observation under real grinding conditions through the ingenious combination of CCD camera, LED light source, assembled observation components and grinding machine body.
[0004] The technical solution of this utility model is: An in-situ observation device for grinding slurry in grinding and polishing includes a grinding machine body 10, which includes a control console 1, a grinding table 9, a drain port 11, a clamp 15, and a baffle 17. The in-situ observation device also includes a dark box 5, a storage tank 6, a camera bracket 12, a CCD camera 13, an LED light source 14, and an assembly observation component 16. The dark box 5 is fixedly installed above the grinding area of the grinding machine body 10. The grinding table 9, camera bracket 12, CCD camera 13, LED light source 14, clamp 15, and assembly observation component 16 are placed inside the dark box 5. The camera bracket 12 is fixedly installed on the outside of the grinding table 9, the CCD camera 13 is fixedly installed at the lower end of the camera bracket 12, and the LED light source 14 is coaxially installed at the lower end of the lens of the CCD camera 13. The clamp 15 is fixedly installed on the outside of the grinding table 9 and is distributed circumferentially with the camera bracket 12. The assembly observation component 16 is movably placed on the surface of the grinding table 9 and clamped and fixed by the clamp 15. The storage tank 6 is used to provide grinding slurry.
[0005] Furthermore, the in-situ observation device also includes a grinding fluid stirring device 7; the grinding fluid stirring device 7 includes a first housing 8, a stirrer 19, a motor 20, and a ball valve 21; the storage tank 6 is fixed on the first housing 8, the motor 20 is fixedly installed inside the first housing 8, the output shaft of the motor 20 passes through the first housing 8 and its extended end is coaxially connected to one end of the stirrer 19, the other end of the stirrer 19 extends vertically into the storage tank 6 and there is a gap between the stirring blades of the stirrer 19 and the inner wall of the storage tank 6; the storage tank 6 provides grinding fluid to the grinding area through a curved conduit 22 and a ball valve 21 is installed on the curved conduit 22.
[0006] Furthermore, the assembly observation component 16 includes an iron ring 25, a grinding plate 26, and an iron ring slot 26-1; the iron ring slot 26-1 is located on the upper side of the pressure area of the grinding plate 26 and is integrally formed with the grinding plate 26; the iron ring 25 is detachably installed on the upper surface of the grinding plate 26 and is located outside the iron ring slot 26-1.
[0007] Furthermore, the grinding plate 26 has a positioning boss on the side away from the iron ring groove 26-1; the boss is used to install the workpiece.
[0008] Furthermore, the grinding plate 26 is made of a transparent material.
[0009] Furthermore, the LED light source 14 includes a light source housing, an LED light strip 24, and a light guide plate 23. The LED light strip 24 is fixed in a ring array inside the light source housing, and the light guide plate 23 is movably installed on the side of the light source housing facing the grinding table 9 by a snap-fit and is parallel to the surface of the grinding table 9.
[0010] The beneficial effects of this utility model are: First, this utility model integrates a stirring device on the basis of a grinding machine. The storage tank of the stirring device contains grinding fluid with tracer particles. The stirring device can uniformly mix the grinding fluid containing tracer particles and transport it to the grinding processing area, which solves the problem that the state of the grinding fluid does not match the actual processing in the existing device.
[0011] Secondly, this invention integrates a CCD camera and camera bracket into the grinding machine. During the grinding of the wafer surface, it can acquire images of the grinding pad in real time. When observing the flow rate of the grinding fluid, the CCD camera position is adjusted to be 3-5mm away from the top surface of the grinding plate of the observation component. The dark chamber is closed, the switch is turned on, and after the grinding fluid is fully distributed on the grinding pad, the actual fluid flow rate under processing conditions can be directly measured. When observing the uniformity of the grinding fluid distribution, the CCD camera bracket is adjusted and a low-magnification lens is replaced so that the entire grinding pad image can be fully displayed within the lens. The dark chamber is closed, the switch is turned on, and after the grinding fluid is fully distributed on the grinding pad, the uniformity of the grinding fluid distribution on the grinding pad surface can be completely observed. This solves the shortcomings of existing technologies that cannot obtain data on the true flow rate and distribution of the grinding fluid, providing a basis for the quality evaluation of the grinding pad.
[0012] Third, this invention designs and assembles an observation component based on a grinding machine. The device is made of highly transparent acrylic sheet, ensuring clear identification of the grinding fluid flow state by the CCD camera. The upper end of the observation component is a pressure application area, and the lower end is a wafer assembly area. Different weight iron rings can be replaced in the pressure application area to ensure different pressures are applied to the wafer. The connection between the acrylic sheet and the iron ring in the pressure application area is as follows: heat the paraffin wax to melt it, apply it to the iron ring, and bond it to the upper end of the observation component. The pressure application area of the observation component has an iron ring slot to ensure the coaxiality of the iron ring and the grinding plate. After the temperature drops to room temperature, the iron ring and the grinding plate are fixed. The bonding method between the wafer and the observation component is also as follows: heat the paraffin wax and apply it evenly to the wafer surface. After the temperature cools down, the wafer is bonded. The paraffin wax hot-melt bonding method is not only simple to operate and facilitates quick replacement of iron rings and wafers, but also ensures the transparency of the observation path and ensures the observation accuracy.
[0013] Fourth, this utility model integrates a dark box into the grinding machine, which works in conjunction with an LED light source to reduce ambient light interference. When the equipment is running, the LED light source is turned on, and the tracer particle images captured by the CCD camera are clearer, effectively improving the clarity of the tracer particle images and enhancing the accuracy of flow velocity measurement and distribution observation. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the internal cross-sectional structure of the grinding fluid stirring device of this utility model; Figure 3 This is a front view of the dark box of this utility model; Figure 4 This is a partial view of the dark box of this utility model; Figure 5 This is a schematic diagram of the cross-section of the LED light source of this utility model; Figure 6 This is a schematic diagram of the assembly observation component of this utility model.
[0015] The following are the labels in the diagram: 1. Control console; 2. LCD display; 3. Power switch; 4. Emergency stop button; 5. Dark box; 6. Liquid storage tank; 7. Grinding slurry stirring device; 8. First housing; 9. Grinding table; 10. Grinding machine body; 11. Grinding slurry outlet; 12. Camera bracket; 13. CCD camera; 14. LED light source; 15. Fixture; 16. Assembly observation components; 17. Baffle; 18. Upper position; 19. Stirrer; 20. Electric motor; 21. Ball valve; 22. Bending conduit; 23. Light guide plate; 24. LED light strip; 25. Iron ring; 26. Grinding plate; 26-1. Iron ring slot. Detailed Implementation
[0016] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.
[0017] Example 1: As Figures 1-6As shown, an in-situ observation device for grinding and polishing fluid includes a grinding machine body 10. The grinding machine body 10 includes a control console 1, a grinding table 9, a drain port 11, a clamp 15, and a baffle 17. The control console 1 includes an LCD display 2, a power switch 3, and an emergency stop button 4. The LCD display 2 is embedded in the front face of the control console 1 and is used to set the device operating parameters. The power switch 3 is used for starting and stopping the device, and the emergency stop button 4 is used to cut off the power source in an emergency. The baffle 17 is annular and surrounds the upper edge of the grinding table 9. It is detachably connected to the inner bottom of the dark box 5 through a slot. One end of the drain port 11 is connected to the lower end of the grinding table 9, and the other end is connected to the lower end of the grinding machine body 10 through an inclined guide channel with an inclination angle ≥15°. The device also includes a dark box 5, a storage tank 6, and a camera support. The dark box 5 is fixedly installed above the grinding area of the grinding machine body 10 by means of welding or other methods. The grinding table 9, camera bracket 12, CCD camera 13, LED light source 14, clamp 15, and assembly observation component 16 are placed inside the dark box 5. The camera bracket 12 is fixedly installed on the outside of the grinding table 9, the CCD camera 13 is fixedly installed at the lower end of the camera bracket 12, and the LED light source 14 is coaxially installed at the lower end of the lens of the CCD camera 13. The clamp 15 is fixedly installed on the outside of the grinding table 9 and is distributed circumferentially with the camera bracket 12. The assembly observation component 16 is movably placed on the surface of the grinding table 9 and clamped and fixed by the clamp 15. The liquid storage tank 6 is used to provide grinding fluid.
[0018] Furthermore, the CCD camera 13 uploads the acquired images to the host computer 18 to achieve human-computer interaction, so that the images can be stored by the host computer and further used for grinding fluid flow rate calculation, etc.
[0019] Furthermore, the in-situ observation device also includes a grinding fluid stirring device 7 arranged outside the dark box 5; the grinding fluid stirring device 7 includes a first housing 8, a stirrer 19, a motor 20, and a precision ball valve 21; the storage tank 6 is fixed on the first housing 8, the motor 20 is fixedly installed inside the first housing 8 by bolts, the output shaft of the motor 20 passes through the top of the first housing 8 and achieves dynamic sealing through a mechanical seal, and the extended end is coaxially connected to one end of the stirrer 19, the other end of the stirrer 19 extends vertically into the lower side of the storage tank 6, and there is a gap between the stirring blade of the stirrer 19 and the inner wall of the storage tank 6, the gap being ≥5mm; the storage tank 6 provides grinding fluid to the grinding area through a curved conduit 22, and a precision ball valve 21 is installed on the curved conduit 22, the precision ball valve 21 is fixedly installed on the outside of the grinding table 9, forming a symmetrical side with the clamp 15.
[0020] Furthermore, the assembly observation component 16 is movably placed on the upper side of the grinding table 9, including an iron ring 25, a grinding plate 26, and an iron ring slot 26-1; the iron ring slot 26-1 is located on the upper side of the pressure area of the grinding plate 26 and is integrally formed with the grinding plate 26; the iron ring 25 is detachably bonded to the upper surface of the grinding plate 26 by heated and molten paraffin wax and is located outside the iron ring slot 26-1, and iron rings 25 of different masses can be replaced according to pressure requirements (mass range 500g-10000g, corresponding to applied pressure 5N-100N, pressure error ≤±2%); the grinding plate 26 is made of highly transparent acrylic material, which is made by turning an acrylic round plate and the upper and lower surfaces are smooth mirror surfaces; the clamp 15 fixes the position of the assembly observation component 16 on the grinding table 9 by clamping the outer periphery of the iron ring 25.
[0021] Furthermore, the grinding plate 26 has an integrated positioning boss on the side away from the iron ring groove 26-1, and the material is the same as that of the grinding plate 26; the boss is used to install workpieces (such as wafers).
[0022] Furthermore, the LED light source 14 includes a light source housing, an LED light strip 24, and a light guide plate 23. The LED light strip 24 is fixed in a ring array inside the light source housing. The light guide plate 23 is movably installed on the side of the housing facing the grinding table 9 by a snap fastener and is parallel to the surface of the grinding table 9. The light source housing is annular, and its inner diameter is larger than the lens diameter of the CCD camera 13. It is coaxially fixed to the lower end of the CCD camera 13.
[0023] Furthermore, the CCD camera 13 is fixedly installed at the end of the camera bracket 12, and the camera bracket 12 is provided with a height adjustment knob (adjustment range 0-30cm); the CCD camera 13 acquires images of the contact area between the polishing slurry and the wafer in real time through the transparent polishing plate 26, and transmits the data to the host computer 18 through the communication interface.
[0024] Before use, place a polishing pad on the polishing table 9 (exemplarily, the polishing pad can be of different patterns, such as: regular hexagon, circle, square, involute, etc.). The polishing pad is connected to the polishing table 9 by magnetic adsorption, and it is ensured that there is no relative slippage when the rotation speed of the polishing table 9 is ≤300r / min. The paraffin wax (exemplarily, the paraffin wax is medical grade solid paraffin wax with a melting point of 55-65℃) is heated to 70-80℃ and melted by a constant temperature heating table. When it is applied to the area directly below the assembly observation component 16, the thickness of the paraffin wax layer is controlled to be 0.1-0.3mm, so that the wafer (exemplarily, the wafer includes but is not limited to SiC (4H / 6H type), K9 optical glass, sapphire (Al2O3), silicon (Si) and other hard and brittle materials) is attached to its lower end to ensure that the wafer and the polishing pad are in complete contact. Apply appropriate pressure to ensure adhesion. After standing for 30-60 seconds, the bonding is completed to avoid oxidation of the wafer surface caused by high temperature.
[0025] The following further describes the usage process of this utility model: Heated paraffin wax is applied to the lower end of the iron ring 25 to which pressure needs to be applied, so that the iron ring 25 is fixed to the upper end of the assembly observation component 16 by paraffin wax hot-melt bonding. By replacing iron rings 25 of different masses, observation of the liquid phase under different pressures can be achieved; the angle of the clamp 15 is adjusted and fixed by the hexagonal bolts on the clamp 15, and the assembly observation component 16 with the iron ring 25 and the wafer is placed on the polishing pad; the polishing slurry containing tracer particles (exemplarily, the PSP tracer particles in the polishing slurry have a particle size of 5-10 μm and a concentration of 0.1-0.5 wt%) is injected into the storage tank 6; the polishing slurry stirring device 7 is turned on, and the motor 20 drives the stirrer 19 to stir the polishing slurry containing PSP tracer particles evenly; the speed at which the polishing slurry enters the curved conduit 22 and flows to the polishing pad is controlled by adjusting the angle of the precision ball valve 21, and the flow rate of the polishing slurry is controlled within a range of 10. -50mL / min; adjust the camera bracket 12 as needed. When observing the flow rate of the grinding fluid, adjust the CCD camera 13 through the Z-axis precision displacement stage of the camera bracket 12 (e.g., adjust it to be 3-5mm away from the top surface of the grinding plate in the assembly observation component). At this time, the PSP tracer particle image occupies 5-20 pixels, which meets the accuracy requirements of the particle image velocimetry (PIV) algorithm. When observing the distribution of the grinding fluid, switch to a low-magnification lens and adjust the camera bracket 12 so that the image in the lens can cover the wafer (exemplarily: make the height of the CCD camera 13 15-20mm away from the top surface of the grinding plate 26). Adjust the illuminance of the LED light source 14 to 15000-20000 lux for observation. After the above work is completed, turn on the LED light source 14 (exemplarily, the LED light source is a white surface light source with an adjustable illuminance range of 5000-20000 lux to ensure clear imaging of the tracer particles) and turn off the dark box 5.
[0026] During operation, the control console 1 is turned on to control the grinding table 9 to rotate, which in turn causes the grinding pad above to rotate. The assembly observation component 16 rotates under the friction of the grinding pad and the support force of the clamp 15. After the grinding fluid on the grinding pad reaches dynamic equilibrium, the CCD camera 13 acquires images in real time through the transparent assembly observation component 16, connects to the communication interface, and transmits the data to the host computer 18 to obtain the grinding fluid distribution image. The host computer then calculates the grinding fluid flow rate value, and the waste liquid is discharged through the drain port 11.
[0027] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.
Claims
1. An in-situ observation device for grinding slurry in grinding and polishing, comprising a grinding machine body (10), wherein the grinding machine body (10) includes a control console (1), a grinding table (9), a drain port (11), a clamp (15), and a baffle (17), characterized in that, The in-situ observation device also includes a dark box (5), a liquid storage tank (6), a camera bracket (12), a CCD camera (13), an LED light source (14), and an assembly observation component (16). The dark box (5) is fixedly installed above the grinding area of the grinding machine body (10). The grinding table (9), camera bracket (12), CCD camera (13), LED light source (14), clamp (15), and assembly observation component (16) are placed inside the dark box (5). The camera bracket (12) is fixedly installed on the outside of the grinding table (9). The CCD camera (13) is fixedly installed at the lower end of the camera bracket (12). The LED light source (14) is coaxially installed at the lower end of the lens of the CCD camera (13). The clamp (15) is fixedly installed on the outside of the grinding table (9) and is spaced apart from the camera bracket (12) along the circumferential direction. The assembly observation component (16) is movably placed on the surface of the grinding table (9) and clamped and fixed by the clamp (15). The liquid storage tank (6) is used to provide grinding fluid.
2. The in-situ observation apparatus for polishing slurry for polishing according to claim 1, wherein The in-situ observation device also includes a grinding slurry stirring device (7); the grinding slurry stirring device (7) includes a first housing (8), a stirrer (19), a motor (20), and a ball valve (21); the storage tank (6) is fixed on the first housing (8), the motor (20) is fixedly installed inside the first housing (8), the output shaft of the motor (20) passes through the first housing (8) and its extended end is coaxially connected to one end of the stirrer (19), the other end of the stirrer (19) extends vertically into the storage tank (6) and there is a gap between the stirring blade of the stirrer (19) and the inner wall of the storage tank (6); the storage tank (6) provides grinding slurry to the grinding area through a curved conduit (22) and a ball valve (21) is installed on the curved conduit (22).
3. The in-situ observation apparatus for polishing slurry for polishing according to claim 1, wherein The assembly observation component (16) includes an iron ring (25), a grinding plate (26), and an iron ring slot (26-1); the iron ring slot (26-1) is located on the upper side of the pressure area of the grinding plate (26) and is integrally formed with the grinding plate (26); the iron ring (25) is detachably installed on the upper surface of the grinding plate (26) and is located outside the iron ring slot (26-1).
4. The in-situ observation apparatus for polishing slurry for polishing according to claim 3, wherein The grinding plate (26) has a positioning boss on the side away from the iron ring groove (26-1); the boss is used to install the workpiece.
5. The in-situ observation apparatus for polishing slurry for polishing according to claim 3, wherein The grinding plate (26) is made of transparent material.
6. The in-situ observation apparatus for polishing slurry for polishing according to claim 1, wherein The LED light source (14) includes a light source housing, an LED light strip (24) and a light guide plate (23). The LED light strip (24) is fixed in a ring array inside the light source housing. The light guide plate (23) is installed on the side of the light source housing facing the grinding table (9) by a snap fastener and is parallel to the surface of the grinding table (9).