Microporous ceramic sucker
By designing microporous ceramic suction cups, using vacuum ring grooves and linear micropore arrays to achieve accurate alignment and calibration of wafers, the problem of inaccurate alignment in the prior art is solved and the detection accuracy is improved.
Patent Information
- Application Number
- CN202411690076.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-02-21
AI Technical Summary
The prior art cannot accurately align wafers, resulting in large errors in imaging and defect detection, affecting detection accuracy.
Design a microporous ceramic suction cup, with ceramic rings of different diameters distributed on the disk surface, vacuum ring grooves are formed between the ring tables, vacuum suction holes and linear micropore arrays are set, and crystals are realized through vacuum suction force and high contrast micropore arrays. Accurate alignment and calibration of circles.
Through the ceramic-structured suction cup and high-contrast micropore array, precise alignment and calibration of the wafer is achieved, the accuracy of imaging and defect detection is improved, and pixel deviation is reduced.
Smart Images
Figure CN119495626A_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present application relate to the field of wafer inspection, and in particular to a microporous ceramic suction cup. Background Art
[0002] The wafer production and processing process is complex and closely linked. The cost of processing and production is high, and the quality requirements of each process are higher. In actual production, every step of the process from designing the wafer substrate to the final etching completion needs to be quality tested, so that quality problems of wafer products can be discovered in time, so that process adjustments can be made or problematic wafers can be scrapped to stop losses in time.
[0003] In the related art, a stage suction cup is used to receive the wafer transferred by the robot arm. In order to smoothly move the wafer from the clamp of the robot arm to the suction cup, a groove for supporting the movement of the arm is generally provided. However, due to the bending and warping of the wafer, the two clamping arms cannot completely carry the wafer, that is, when the suction cup absorbs the wafer, the clamping arm will be broken. In view of this, a new clamping scheme and clamping arm are designed, and the original suction cup with grooves is not applicable. Furthermore, when the robot arm places the aligned wafer on the wash plate, there will still be errors. The error of the wafer that has not been corrected for secondary deviation is measured to be 1mm, and reflected in the imaging picture with a pixel of 2.5 microns, there will be a deviation of about 500 pixels, which seriously affects the defect detection of the image wafer. Summary of the invention
[0004] The embodiment of the present application provides a microporous ceramic suction cup to solve the problem that the related technology cannot accurately align the wafer. The microporous ceramic suction cup is circular, and a plurality of ceramic rings of different diameters are distributed on the disk surface, and the ceramic rings of different diameters are arranged co-centrically with the circular disk surface;
[0005] A vacuum ring groove is formed between adjacent ceramic ring stages, and a vacuum suction hole is arranged in the vacuum ring groove to absorb and support the wafer held by the ceramic ring stage;
[0006] Linear micropores consisting of a number of circular micropores are opened on different ceramic ring stages, and the micropore centers of the linear micropores are collinear; the micropore centers on different ceramic ring stages are collinear with the disk center; at least two groups of linear micropore arrays with different directions and collinear with the disk center are arranged on each ceramic ring stage, which are used to calibrate the wafer according to the line connecting the micropore centers of the linear micropore arrays.
[0007] Specifically, at least one vacuum suction hole is provided in each vacuum ring groove, and the vacuum suction hole is a circular through hole penetrating through the disk surface, and the bottom of the hole is connected to the gas source through an air path.
[0008] Specifically, the vacuum suction holes located in different vacuum ring grooves are distributed linearly, and the aperture centers of the linearly distributed vacuum suction holes are colinear with the center of the disk surface.
[0009] Specifically, the linear micropores on the ceramic ring stage include at least three circular micropores with the same structural size, and each circular micropore is embedded with a white filler.
[0010] Specifically, the substrate of the microporous ceramic suction cup is an aluminum oxide matrix, and the surfaces of the ceramic ring and the disc are hard-oxidized and treated to be black.
[0011] Specifically, the ceramic disk surface in the vacuum ring groove is set to be black, and honeycomb micropores are arranged on the surface.
[0012] Specifically, three ceramic rings are arranged on the disk surface, and the diameters thereof are respectively larger than 125 mm, 210 mm and 320 mm.
[0013] Specifically, the diameter of the circular micropores does not exceed 0.5 mm, and the distance between the centers of adjacent circular micropores does not exceed 0.75 mm.
[0014] Specifically, a plurality of mounting holes are evenly distributed on each of the ceramic ring platforms, and the mounting holes on different ceramic ring platforms are staggered.
[0015] Specifically, the diameter of the circular microhole does not exceed 5 mm, and the center distance between two vacuum suction holes in adjacent vacuum ring grooves does not exceed 27 mm.
[0016] The beneficial effects brought about by the technical solution provided in the embodiment of the present application include at least: the present application uses a suction cup with a ceramic structure as a wafer carrier, and ceramic rings with different inner diameters are arranged on the disk surface for holding wafers of various sizes. A vacuum ring groove is formed between all the ceramic rings, and the vacuum suction holes opened therein can form a negative pressure to fix the wafer on the disk surface. The linear micropores opened on the ceramic ring stage are composed of a number of circular micropores, and the interior is filled with a filler with a different color from the ceramic matrix to form a high contrast. The use of circular micropores instead of marking or grooving can avoid the problem of uneven image correction accuracy under high-precision pixels. The straight line simulated by the center line can further improve the accuracy, and the image of the soft layer is smaller with the high color difference particle filling and non-linear openings, and the identification of multiple particles to determine the straight line is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is a schematic diagram of the system for wafer loading deviation correction;
[0018] Figure 2 It is a schematic diagram of wafer loading deviation correction provided in an embodiment of the present application;
[0019] Figure 3 is a schematic diagram of the structure of a microporous ceramic suction cup provided in an embodiment of the present application;
[0020] Figure 4 It is a top view of the ceramic suction cup;
[0021] Figure 5 yes Figure 4 The enlarged view of point A in the middle;
[0022] Figure 6 is a schematic diagram of setting linear microholes in the form of cross marks;
[0023] Figure 7 The corresponding Figure 6 The enlarged view of point B in the middle;
[0024] Figure 8 It is a schematic diagram of the position of the vacuum suction hole in the vacuum ring groove;
[0025] Fig. 9 yes Figure 4 The cross-section at A in the middle;
[0026] Fig.10 yes Figure 8 Cross-sectional view at point B. DETAILED DESCRIPTION
[0027] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.
[0028] The term "multiple" as used herein refers to two or more than two. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the related objects are in an "or" relationship.
[0029] Figure 1 The figure is a schematic diagram of a wafer loading deviation correction system, which includes a detection platform 110, on which a posture adjustment mechanism 120 is arranged, and a carrier 130 is located at the top of the posture adjustment mechanism 120. The traditional defect detection scheme also needs to be equipped with a carrier, which is similar to the basic structure. Figure 1 The structure of the middle stage is similar, but the difference is that the stage 130 of the present application is controlled by the posture adjustment mechanism 120, and can be raised and lowered and the displacement angle can be adjusted as needed, that is, it can be changed arbitrarily within the spatial range. The structure of the stage 130 is usually set to be circular, which is consistent with the shape of the wafer 140 to be tested. The deviation correction of the present application scheme is mainly achieved through the posture adjustment mechanism 120, and because the control stage 130 moves in a three-dimensional plane, in order to ensure that the wafer 140 to be tested can be firmly on the stage 130, it is necessary to set a suction cup or suction hole on the stage 130 to fix it.
[0030] After the wafer is placed on the stage by the robotic arm, a camera directly above the stage or fixed at a specific position scans the state image of the wafer placed on the stage, i.e., the wafer state diagram. This application takes a circular stage as an example. In theory, the wafer should be clamped and placed in the center of the stage, but due to factors such as errors, the actual wafer cannot fall accurately to the center. Figure 2 The left side of the figure shows an image of the stage 210 before loading. In order to facilitate the subsequent determination of the stage deviation, a target area 220 can be set on the stage 210. The target area can be a mark such as a protrusion or a groove engraved on the stage 210. Figure 2 In the wafer status diagram on the middle right, the blue area is the wafer 240 that has been loaded and placed. From the figure, we can directly see the obvious position deviation between the wafer 240 area and the contour line. Based on the position deviation, the point information of the wafer 240 relative to the carrier 210 can be extracted to represent the actual position information of the wafer 240. There is an obvious position deviation between the placed wafer 240 and the target area 220, which is the reason for the correction.
[0031] This application is designed with the annular groove as the target, and obtains Figure 3 The microporous ceramic suction cup shown is used as Figure 2 The microporous ceramic suction cup is circular, and a plurality of ceramic rings 1 with different diameters are distributed on the upward disk surface. The ceramic rings 1 with different diameters are arranged co-centrically with the circular disk surface, corresponding to Figure 3 The ceramic ring stages 1 form a concentric circle layout.
[0032] Because the wafer must not be displaced relative to the stage during the movement process, the concave portions between adjacent ceramic ring stages 1 form vacuum ring grooves 2. A number of vacuum suction holes may be provided in the vacuum ring grooves 2, through which the wafer held by the ceramic ring stage is sucked.
[0033] Linear micropores 3 composed of a plurality of circular micropores are provided on different ceramic ring platforms 1 , each linear micropore contains a plurality of circular micropores, and the centers of the micropores of all the circular micropores are on the same line. Figure 4 This is a top view of the ceramic suction cup. In the figure, the mark A is a linear microhole on one of the ceramic ring platforms 1. Figure 5 is Figure 4 The enlarged view of A in the middle, combined with Figure 4 It can be seen that the centers of the microholes on different ceramic rings are in line with the center of the disk. Because the wafer deflection correction requires the use of coordinate systems and auxiliary lines as references, multiple groups of linear microholes 3 are set in multiple directions on the ceramic disk, so that the centers of the microholes 3 and the center of the disk form a straight line, which is equivalent to directly engraving natural auxiliary lines on the disk as a reference.
[0034] In a possible implementation, at least two sets of linear microhole arrays in different directions and colinear with the center of the disk surface can be set on each ceramic ring stage, for wafer calibration based on the microhole center line of the linear microhole array. Assuming that the system calibration uses a rectangular coordinate system for alignment correction, it is set in the form of a cross mark. Figure 6 This is a schematic diagram of setting linear microholes in the form of cross marks. Figure 7 The corresponding Figure 6 The enlarged view at B in the figure shows that the linear microholes 3 on the adjacent ceramic ring platforms 1 are collinearly arranged (with the centers of the microholes collinear).
[0035] like Figure 5 As shown, in a possible embodiment, each group of linear microholes 3 on the ceramic ring stage 1 includes at least 3 circular microholes of the same structural size, and each circular microhole is embedded with a white filler, or a filler with a large difference in color from the background of the ceramic suction cup, for rapid identification in the image. Figure 6 The red line in the Figure 2 The red auxiliary lines constructed during the image processing in the correction stage are equivalent to the constructed coordinate system. The diameter of the circular microhole is set not to exceed 0.5mm, and the distance between the centers of adjacent circular microholes does not exceed 0.75mm, so that the image obtained by the high-precision line scan camera will not be distorted after magnification. Because it is assumed that lines are used to draw lines on the disk surface, uneven line thickness will inevitably appear after high-precision magnification. This is because the error of the wafer that has not been corrected for secondary offset is measured to be 1mm, and reflected in the imaging picture with a pixel of 2.5 microns, there will be a deviation of about 500 pixels, and the uneven line thickness will be magnified, and the center line cannot be selected, which ultimately leads to a larger error in the correction result. The solution of slotting will also be affected by accuracy. Therefore, this application adopts the method of linear hole opening as a reference, and the circular microhole can use the center of the circle as the connection standard, so that the accuracy of establishing auxiliary lines and coordinate systems is higher.
[0036] In some possible implementations, in order to accommodate wafers of various sizes, three ceramic rings may be provided on the disk surface, with the inner or outer ring diameters being greater than 125 mm, 210 mm, and 320 mm, respectively, and at least three wafers of different sizes may be sucked.
[0037] like Figure 8 As shown, in order to ensure that wafers of different sizes can be adsorbed and not fall off, at least one vacuum suction hole 21 can be set in each vacuum ring groove 2. The vacuum suction hole 21 is a circular through hole that penetrates the disk surface, and the bottom of the hole is connected to the gas source through an air path. In order to ensure that the groove loop can form a negative pressure, the height of each ceramic ring stage 1 should be kept consistent, so that the wafer surface can be adsorbed between adjacent vacuum ring grooves 2.
[0038] In some embodiments, the vacuum suction holes 21 located in different vacuum ring grooves 2 are also distributed linearly, and the centers of the apertures of the linearly distributed vacuum suction holes 21 are also colinear with the center of the disk surface. Figure 8 Each vacuum ring groove 2 includes at least one vacuum suction hole 21. Of course, in order to improve the adsorption effect and adsorption balance, two or more vacuum suction holes 21 can be symmetrically arranged, similar to the cross mark distribution form or other forms.
[0039] In order to ensure that the wafer state image is clear and has contrast, the suction cup can be designed as a ceramic structure, and the base of the microporous ceramic suction cup is designed with an alumina matrix. At the same time, the ceramic ring stage 1 and the surface of the disk are hard-oxidized and the color is processed to black. The black ring stage and surface formed in this way can form a sharp color contrast with the white filler in the circular micropores, thereby improving recognition.
[0040] Furthermore, the ceramic disk surface in the vacuum ring groove 2 can also be set to black, and honeycomb micropores are set on the inner surface of the groove. Figure 4 The texture formed by the honeycomb micropores can improve the recognition effect, especially when it is the same color as the ceramic ring 1. Different sizes can be quickly identified by the texture, corresponding to different target areas, and the deviation between the wafer and the target area can be quickly identified. This ceramic structure and surface oxidation treatment design can remove the electrostatic effect and protect the wafer from damage under mechanical operation conditions.
[0041] In some embodiments, the ceramic suction cup needs to be installed on the posture adjustment mechanism, so a mounting hole 4 is extended inwardly or outwardly on the ceramic ring 1 of the disk surface. The number of mounting holes on each ceramic ring 1 is set according to actual needs. This application takes 3 as an example. Figure 4 In the embodiment, the mounting holes 4 on different ceramic rings 1 are arranged in a staggered manner. That is, on ceramic rings 1 of the same size, the spacing between adjacent mounting holes 4 is 120 degrees, while the spacing between two adjacent mounting holes 4 of different sizes is 60 degrees. Of course, other angles can be selected to achieve force balance and stability.
[0042] Fig. 9 yes Figure 4 In the cross-sectional view at A, the thickness of the ceramic plate base 10 in the cross-sectional view is designed to be 20 mm, and the depth of the groove does not exceed 20 mm. In particular, because a honeycomb microporous pattern is also provided in the groove, the pattern also needs to occupy a certain thickness, and the overall proportion balance can be maintained during the design.
[0043] Fig.10 yes Figure 8In the cross-sectional view at B in the middle, the structure of the vacuum suction hole 21 adopts a through design to connect the air path below, the hole diameter is designed to be 5mm, and the center distance between two vacuum suction holes in adjacent vacuum ring grooves does not exceed 27mm. In addition, the vacuum suction hole 21 is opened on the basis of honeycomb micropores, so Fig.10 On the basis of the medium vacuum ring groove 2, the depth of the honeycomb micropores is designed to be 1 mm to form clear textures.
[0044] In summary, the present application uses a suction cup with a ceramic structure as a wafer carrier, and ceramic rings with different inner diameters are arranged on the disk surface for holding wafers of various sizes. A vacuum ring groove is formed between all the ceramic rings, and the vacuum suction holes opened therein can form a negative pressure to fix the wafer on the disk surface. The linear micropores opened on the ceramic ring are composed of a number of circular micropores, and the interior is filled with a filler with a different color from the ceramic matrix to form a high contrast. The use of circular micropores instead of marking or grooving can avoid the problem of uneven image correction accuracy under high-precision pixels. The straight line simulated by the center line can further improve the accuracy. The combination of high color gradation difference particle filling and non-linear openings makes the image of the soft layer smaller, and the identification of multiple particles to determine the straight line is more accurate.
[0045] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.
Claims
1. A microporous ceramic suction cup, characterized in that: The microporous ceramic suction cup is circular, and a plurality of ceramic rings with different diameters are distributed on the surface of the cup, and the ceramic rings with different diameters are arranged co-centrically with the circular cup; A vacuum ring groove is formed between adjacent ceramic ring stages, and a vacuum suction hole is arranged in the vacuum ring groove to absorb and support the wafer held by the ceramic ring stage; Linear micropores consisting of a number of circular micropores are opened on different ceramic ring stages, and the micropore centers of the linear micropores are collinear; the micropore centers on different ceramic ring stages are collinear with the disk center; at least two groups of linear micropore arrays with different directions and collinear with the disk center are arranged on each ceramic ring stage, which are used to calibrate the wafer according to the line connecting the micropore centers of the linear micropore arrays.
2. The microporous ceramic suction cup according to claim 1, characterized in that: At least one vacuum suction hole is arranged in each vacuum ring groove, and the vacuum suction hole is a circular through hole penetrating through the disk surface, and the bottom of the hole is connected to the gas source through an air path.
3. The microporous ceramic suction cup according to claim 2, characterized in that: The vacuum suction holes located in different vacuum ring grooves are distributed linearly, and the aperture centers of the linearly distributed vacuum suction holes are colinear with the center of the disk surface.
4. The microporous ceramic suction cup according to claim 1, characterized in that: The linear micropores on the ceramic ring stage include at least three circular micropores with the same structural size, and each circular micropore is embedded with a white filler.
5. The microporous ceramic suction cup according to claim 4, characterized in that: The base of the microporous ceramic suction cup is an aluminum oxide matrix, and the surfaces of the ceramic ring and the disc are hard-oxidized and processed to be black.
6. The microporous ceramic suction cup according to claim 5, characterized in that: The ceramic disk surface in the vacuum ring groove is set to be black, and honeycomb micropores are arranged on the surface.
7. The microporous ceramic suction cup according to any one of claims 1 to 6, characterized in that: Three ceramic rings are arranged on the disk, with diameters larger than 125 mm, 210 mm and 320 mm respectively.
8. The microporous ceramic suction cup according to claim 4, characterized in that: The diameter of the circular micropores does not exceed 0.5 mm, and the distance between the centers of adjacent circular micropores does not exceed 0.75 mm.
9. The microporous ceramic suction cup according to claim 2, characterized in that: A plurality of mounting holes are evenly distributed on each of the ceramic ring platforms, and the mounting holes on different ceramic ring platforms are staggered.
10. The microporous ceramic suction cup according to claim 4, characterized in that: The diameter of the circular microhole does not exceed 5 mm, and the distance between the centers of two vacuum suction holes in adjacent vacuum ring grooves does not exceed 27 mm.