Ceramic disc for improving flatness of polished or ground wafer
By setting a protrusion in the center of the ceramic disk, the problem of the wafer edge removal rate being higher than that in the center was solved, and the uniform distribution and pressure adjustment of the polishing slurry on the wafer surface were achieved, thus improving the flatness of the wafer.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING TONGMEI XTAL TECH CO LTD
- Filing Date
- 2025-05-22
- Publication Date
- 2026-05-01
AI Technical Summary
The existing polishing or grinding ceramic disks have insufficient flatness, resulting in a higher removal rate at the wafer edges than at the center and inner sides, which affects the final flatness of the wafer.
A raised section is set in the center of the ceramic disk to make the polishing or grinding fluid distribution more uniform. By adjusting the pressure distribution and linear velocity difference on the wafer surface, the mechanical action at the edge is reduced, and the uniformity of the removal rate is improved throughout the wafer.
It achieves uniform distribution of polishing or grinding slurry on the wafer surface, reduces the removal rate at the outer edge of the wafer, improves the flatness of the wafer, ensures the uniformity of the removal rate throughout the wafer, and obtains a wafer with high flatness.
Smart Images
Figure CN224192399U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of wafer processing technology, specifically relating to a ceramic disc for improving the flatness of polished or ground wafers. Background Technology
[0002] Existing polishing or grinding ceramic discs generally require extremely high flatness, the flatter the better. However, flat ceramic discs present some problems. During wafer polishing or grinding, the wafer edge is located at the outer edge of the ceramic disc. When using a flat ceramic disc, the center of the wafer cannot fully contact the fresh polishing or grinding fluid. The linear velocity of the outer edge of the ceramic disc is higher than that of other areas, resulting in more chemical polishing fluid in contact with the wafer and a higher linear velocity. This leads to a higher removal rate at the outer edge of the wafer than at the center and inner side. The edge chemical action is strong, and the high linear velocity at the edge also results in strong mechanical action. Ultimately, the removal amount at the wafer edge is higher than that in other areas, leading to a decrease in the final flatness of the wafer. Utility Model Content
[0003] To solve the above problems, the present invention adopts the following technical solution:
[0004] A ceramic disk for improving the flatness of polished or ground wafers includes: a ceramic disk body, wherein the working surface of the ceramic disk body is provided with a protrusion.
[0005] Furthermore, the protrusion and the ceramic disc body are an integral structure.
[0006] Furthermore, the protrusion is located at the center of the end face of the ceramic disc body.
[0007] Furthermore, the center of the protrusion is coaxially arranged with the center of the ceramic disc body.
[0008] Furthermore, the height of the edge of the protrusion is lower than the height of the center of the protrusion.
[0009] Furthermore, the edge of the protrusion extends to the edge of the ceramic disc body.
[0010] Furthermore, the protrusion is detachably provided with multiple wafers along its circumferential edge.
[0011] Furthermore, the polished surface of the wafer is arranged parallel to the cutting plane of the protrusion.
[0012] Furthermore, the ratio of the protrusion height of the protrusion to the diameter of the ceramic disk is 8E-6 to 5.5E-5.
[0013] Beneficial effects:
[0014] This invention provides a ceramic disk with a raised central section for improving wafer flatness. During wafer processing, it reduces the chemical action on the outer edges of the wafer, allowing the polishing or grinding fluid to be evenly distributed on the wafer surface. The raised portion of the ceramic disk adheres to the wafer, ensuring even distribution of the polishing or grinding fluid and reducing the mechanical action on the outer edges. This results in the removal rate at the outer edges of the wafer being equal to the removal rate at the center and inner sides, leading to a more uniform distribution of the polishing fluid and a more uniform removal rate throughout the wafer. Ultimately, this results in a high-flatness wafer with a significantly improved wafer flatness level compared to previous methods. Attached Figure Description
[0015] Figure 1 This is a front view of the ceramic disk that improves the flatness of polished or ground wafers according to the present invention.
[0016] Figure 2 This is a side view of the ceramic disk of the present invention for improving the flatness of polished or ground wafers;
[0017] Figure 3 This is a schematic diagram of the structure connecting the ceramic disc to the wafer and the polishing disc for improving the flatness of polished or ground wafers according to this utility model.
[0018] Figure 4 Comparison of ceramic disc processing and flat disc processing for improving the flatness of polished or ground wafers according to this utility model;
[0019] The components include: 1. Ceramic disc body; 2. Chip; 3. Protrusion; 4. Drive unit; 5. Polished disc. Detailed Implementation
[0020] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings of the embodiments of the present invention.
[0021] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "horizontal," "inner," "outer," and "one side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0022] Example 1
[0023] like Figures 1 to 3 As shown, a ceramic disk for improving the flatness of polished or ground wafers includes: a ceramic disk body 1, and a protrusion 3 is provided on the working surface of the ceramic disk body 1.
[0024] The ceramic disc is circular in shape and has one protrusion 3.
[0025] With the above technical solution, the thickness of the center of the protrusion 3 is lower than the total thickness of the wafer 2 and the protrusion 3 after they are connected, so that when polishing is performed, the polishing disk 5 only polishes the polishing surface of the wafer 2, and the two do not affect each other.
[0026] In this embodiment, the protrusion 3 and the ceramic disc body 1 are an integral structure.
[0027] In this embodiment, the protrusion 3 is located at the center of the end face of the ceramic disc body 1.
[0028] The center of the protrusion 3 coincides with the center of the ceramic disc body 1. The ceramic disc body 1 and the driving part 4 are connected by vacuum adsorption, pressure or other means. The polishing disc 5 is set on the protrusion 3 at one end away from the ceramic disc body 1, and there is a gap between the polishing disc 5 and the protrusion 3. This gap is the flow area of the polishing or grinding fluid.
[0029] In this embodiment, the center of the protrusion 3 is coaxially arranged with the center of the ceramic disc body 1.
[0030] In this embodiment, the height of the edge of the protrusion 3 is lower than the height of the center of the protrusion 3.
[0031] In this embodiment, preferably, the convex surface of the protrusion 3 is arc-shaped, the thickness of the protrusion 3 is d, the sag of the arc-shaped protrusion 3 is equal to the thickness of the protrusion 3, and the thickness of the ceramic disc body is D, where the value of D is greater than the value of d.
[0032] The thickness d of the protrusion 3 ranges from 2 to 20 μm, preferably from 5 to 15 μm; the thickness D of the ceramic disc body is from 5 mm to 25 mm.
[0033] In this embodiment, the edge of the protrusion 3 extends to the edge of the ceramic disc body 1.
[0034] In this embodiment, a plurality of wafers 2 are detachably disposed on the circumferential edge of the protrusion 3.
[0035] Preferably, the wafer 2 is fixed to the ceramic disk with an adhesive, and after polishing or grinding, the wafer is removed from the ceramic disk and the back adhesive is removed, so as to achieve a detachable connection between the wafer 2 and the protrusion 3.
[0036] The above technical solution can adjust the pressure distribution on the surface of wafer 2, optimize the problem of uneven distribution of polishing or grinding fluid in the gap, make the polishing or grinding fluid more evenly distributed between the protrusion 3 and the polishing disk 5, make the removal rate more uniform in all parts of wafer 2, and finally obtain a high flatness wafer.
[0037] In this embodiment, the polished or ground surface of the wafer 2 is arranged parallel to the cutting plane of the protrusion 3.
[0038] The wafer 2 is inclined at a certain angle to the polishing disk 5 or grinding disk, and the inclination angle is the same as the inclination angle of the convex surface of the protrusion 3. The inclination angle of the wafer 2 makes the pressure on the side of the polishing or grinding surface of the wafer 2 away from the center of the protrusion 3 less than the pressure on the side of the polishing surface of the wafer 2 close to the center of the protrusion 3 during polishing or grinding. This makes the mechanical action of the wafer 2 away from the center of the protrusion 3 stronger and the removal rate greater.
[0039] Through the above technical solution, multiple wafers 2 are arranged circumferentially on the edge of the protrusion 3. The wafers 2 are detachably connected to the protrusion 3, and the protrusion 3 is located at the center of the ceramic disk body 1. When the ceramic disk rotates, the edge linear velocity of the outer end of the wafer 2 in the radial direction is greater than the inner and center linear velocities, so that the removal rate of the outer edge of the wafer 2 is greater than the removal rate of the center and inner side. Thus, the removal amount of the wafer 2 at the end closer to the center of the ceramic disk is less than the removal amount of the wafer 2 away from the center of the ceramic disk. Considering the influence of the protrusion 3 on the surface pressure distribution of the wafer 2, the removal rates of the two ends of the outer edge of the wafer 2 are close to or the same as those of the center of the wafer 2, and a wafer 2 with high flatness can be obtained.
[0040] In this embodiment, the ratio of the protrusion height of the protrusion 3 to the diameter of the ceramic disk is 8E-6 to 5.5E-5.
[0041] The protrusion height of the protrusion 3 of the ceramic disk is 0-30 μm.
[0042] The diameter of the ceramic disc varies depending on the model of the polishing or grinding equipment. The diameter of the ceramic disc is 305mm, 360mm, or 485mm, with 360mm being the preferred size.
[0043] Example 2
[0044] The difference between this embodiment and embodiment 1 is that the protrusion 3 is conical in shape, and the angle between the generatrix of the conical protrusion 3 and the axis of rotation is greater than 45 degrees.
[0045] Example 3
[0046] The difference between this embodiment and embodiment 1 is that the protrusion 3 is shaped like a frustum, and the angle between the central axis of the bottom circle of the frustum protrusion 3 and the generatrix is greater than 45 degrees.
[0047] like Figure 4 As shown, the ceramic disc provided by this utility model for improving the flatness of polished or ground wafers is an irregularly shaped ceramic disc with protrusions 3. Figure 4 The irregular ceramic disk is a ceramic disk with a protrusion 3 on the ceramic disk body 1. The disk shape of the ceramic disk has been optimized to reduce the unevenness of the polishing fluid distribution, reduce the mechanical action on the outer edge of the wafer 2, and make the polishing fluid more evenly distributed between the protrusion 3 and the polishing disk 5. This improves the uniformity of the removal rate on the surface of the wafer 2, reduces the mechanical action on the edge, and the flatness of the wafer 2 is significantly improved compared with the previous flat ceramic disk. The TTV value of the irregular ceramic disk is significantly different from that of the flat ceramic disk. The TTV value of the irregular ceramic disk is smaller, and the flatness of the wafer is higher.
[0048] The wafer fabrication process is as follows:
[0049] Step S1: Chamfer the surface of the wafer (or other items that need to be flattened). Step S2: Protect the back of the wafer after chamfering by fixing the wafer to the ceramic disk with adhesive or adsorption pad.
[0050] Step S3: Adsorb or fix the ceramic disk onto the polishing or grinding small head. The polishing or grinding small head and the polishing or grinding large disk work together to polish or grind the main surface of the wafer.
[0051] Step S4: After polishing or grinding, remove the wafer from the polishing or grinding head.
[0052] Step S5: Clean the wafer.
[0053] The ceramic disk provided by this utility model for improving the flatness of polished or ground wafers mainly optimizes the disk shape of the ceramic disk in step S2. During use, the central part of the wafer can fully contact the fresh polishing or grinding fluid. The linear velocity of the outer edge of the ceramic disk is the same as that of the rest of the area, which reduces the unevenness of the distribution of polishing or grinding fluid, reduces the mechanical action at the edge, and results in a high level of final flatness of the product.
[0054] The above are merely preferred embodiments of the present utility model and do not constitute any limitation on the technical scope of the present utility model. Therefore, any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the technical solution of the present utility model.
Claims
1. A ceramic disk for improving the flatness of polished or ground wafers, characterized in that, include: The ceramic disc body has a protrusion on its working surface; the protrusion is located at the center of the end face of the ceramic disc body; and multiple wafers are detachably disposed on the circumferential edge of the protrusion.
2. The ceramic disk for improving the flatness of polished or ground wafers according to claim 1, characterized in that, The protrusion is an integral part of the ceramic disc body.
3. The ceramic disk for improving the flatness of polished or ground wafers according to claim 1, characterized in that, The center of the protrusion is coaxially arranged with the center of the ceramic disc body.
4. The ceramic disk for improving the flatness of polished or ground wafers according to claim 1, characterized in that, The height of the edge of the protrusion is lower than the height of the center of the protrusion.
5. The ceramic disk for improving the flatness of polished or ground wafers according to claim 3, characterized in that, The edge of the protrusion extends to the edge of the ceramic disc body.
6. The ceramic disk for improving the flatness of polished or ground wafers according to claim 1, characterized in that, The polished surface of the wafer is arranged parallel to the cutting plane of the protrusion.
7. The ceramic disk for improving the flatness of polished or ground wafers according to claim 1, characterized in that, The ratio of the protrusion height to the diameter of the ceramic disc is 8E-6 to 5.5E-5.