A type of chuck

Abstract

This invention relates to the field of optical inspection technology, and more particularly to a chuck, comprising: a body having a first surface; a boss located on the first surface, the boss and the body forming a cavity, the first surface facing the cavity having a light-absorbing layer, and the surface of the boss away from the body serving as a bearing surface for supporting a light-transmitting workpiece; wherein the boss includes an outer ring boss and an inner ring boss, the outer ring boss being located outside the inner ring boss and higher than the inner ring boss. This invention at least improves the inspection efficiency and accuracy of light-transmitting workpieces.

Description

Technical Field

[0001] This invention belongs to the field of optical detection technology, and particularly relates to a chuck. Background Technology

[0002] With the development of semiconductor technology, the materials used to prepare wafers and chips have also been gradually improved. Silicon carbide is the core representative of third-generation semiconductor materials. Due to its wide bandgap characteristics, it is called wide bandgap semiconductor material. Wide bandgap semiconductor materials have shown great potential to surpass traditional silicon materials in high-power, high-frequency and high-temperature applications.

[0003] However, wafers made of silicon carbide have light-transmitting properties. During the optical inspection of wafers, because the wafers are light-transmitting, the inspection light is partially reflected and partially transmitted after it is incident on the wafer. The transmitted light is reflected after it is incident on the chuck that carries the wafer and passes through the wafer again to enter the inspection equipment, generating unwanted stray light, which leads to low resolution and blurry images. Summary of the Invention

[0004] In view of this, the present invention aims to provide a chuck that at least helps to improve the detection efficiency and accuracy of light-transmitting workpieces.

[0005] To achieve the above objectives, the technical solution created by this invention is implemented as follows: This invention provides a chuck, comprising: a body having a first surface; a boss located on the first surface, the boss and the body forming a cavity, the first surface facing the cavity having a light-absorbing layer, and the surface of the boss away from the body being a bearing surface for bearing a light-transmitting workpiece; wherein the boss includes an outer ring boss and an inner ring boss, the outer ring boss being located outside the inner ring boss and the outer ring boss being higher than the inner ring boss.

[0006] Furthermore, the height difference between the outer ring boss and the inner ring boss is within a first preset range.

[0007] Furthermore, the material of the body includes aluminum, the light-absorbing layer is black, and the surface roughness of the light-absorbing layer is within a second preset range.

[0008] Furthermore, the bearing surface has an adsorption groove, and the bottom of the adsorption groove has an adsorption hole.

[0009] Furthermore, the cavity includes a first cavity and a second cavity, with the inner ring boss and the body forming the first cavity, and the outer ring boss, the inner ring boss, and the body forming the second cavity.

[0010] Furthermore, the first surface has a pick-and-place groove that extends from the edge of the main body to the first cavity, and the bottom surface of the pick-and-place groove is flush with the bottom surface of the first cavity.

[0011] Furthermore, the depth of the first cavity is within a third preset range.

[0012] Furthermore, the chuck also includes a resolution calibration structure and / or an autofocus calibration structure, the resolution calibration structure being located outside the boss and the autofocus calibration structure being located outside the boss.

[0013] Furthermore, the resolution calibration structure includes a first fixing member and a resolution calibration member. A first part of the first fixing member is fixed to a first surface, and a second part of the first fixing member is located on the outside of the body. The resolution calibration member is disposed on the second part of the first fixing member, and the top surface of the resolution calibration member is flush with the bearing surface of the outer ring boss. And / or, the autofocus calibration structure includes a second fixing member and an autofocus calibration member. A first part of the second fixing member is fixed to a first surface, and a second part of the second fixing member is located on the outside of the body. The autofocus calibration member is disposed on the second part of the second fixing member, and the top surface of the autofocus calibration member is flush with the bearing surface corresponding to the outer ring boss.

[0014] Furthermore, the chuck also includes multiple limiting members located on the first surface. The limiting members are located outside the boss and are higher than the boss. The limiting members radially abut against the workpiece to limit the position of the workpiece.

[0015] Compared with the prior art, the present invention achieves the following beneficial effects: The present invention provides a chuck suitable for optical inspection of transparent workpieces. By setting a boss on the body of the chuck and using the boss and the body to form a cavity, and setting a light-absorbing layer on the first surface of the body facing the cavity, the detection light transmitted through the wafer is absorbed by the light-absorbing layer and will not be reflected and pass through the transparent workpiece into the inspection equipment. This alleviates the negative impact of stray light generated by the detection light incident on the chuck on the detection accuracy and efficiency, and is conducive to improving the detection efficiency and accuracy of transparent workpieces. In addition, the boss includes an outer ring boss and an inner ring boss, the outer ring boss is located outside the inner ring boss, and the outer ring boss is higher than the inner ring boss. The inner ring boss, with bosses of varying heights, supports light-transmitting workpieces of different sizes. This allows the chuck to accommodate workpieces of various dimensions. When supporting small workpieces, the small workpiece only contacts the inner ring boss. The height difference between the inner and outer ring bosses ensures that when supporting large workpieces, the large workpiece only contacts the outer ring boss. Thus, regardless of whether the workpiece is large or small, it always contacts only one boss, minimizing contact between the chuck and the workpiece. This reduces the reflection of transmitted light by the portion of the chuck in contact with the workpiece, reducing stray light and improving the efficiency and accuracy of workpiece inspection. Attached Figure Description

[0016] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the chuck structure described in the embodiment of the present invention; Figure 2 An enlarged structural schematic diagram of the limiting member and part of the outer ring boss described in the embodiment of the present invention; Figure 3 A schematic diagram of the resolution calibration structure described in the embodiment of the present invention; Figure 4 A schematic diagram of the autofocus calibration structure described in the embodiment of the present invention.

[0017] Explanation of reference numerals in the attached drawings: 10, body; 13, first surface; 120, cavity; 12, bearing surface; 101, outer ring boss; 102, inner ring boss; 110, adsorption groove; 122, first cavity; 121, second cavity; 112, pick-and-place groove; 11, robotic arm; 130, resolution calibration structure; 140, autofocus calibration structure; 131, first fixing component; 132, resolution calibration component; 141, second fixing component; 142, autofocus calibration component; 133, first groove; 143, second groove; 111, limiting component. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and 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, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] refer to Figure 1 The present invention provides a chuck, comprising: a body 10 having a first surface 13; a boss located on the first surface 13, and the boss and the body 10 forming a cavity 120, the first surface 13 facing the cavity 120 having a light-absorbing layer, and the surface of the boss away from the body 10 being a bearing surface 12 for bearing a light-transmitting workpiece; wherein the boss includes an outer ring boss 101 and an inner ring boss 102, the outer ring boss 101 being located outside the inner ring boss 102, and the outer ring boss 101 being higher than the inner ring boss 102.

[0024] It should be noted that the outer contour of the body 10 can be in other regular or irregular shapes such as circles, triangles, quadrilaterals, pentagons or hexagons, to accommodate light-transmitting workpieces of different shapes.

[0025] In some embodiments, the light-transmitting workpiece can be a light-transmitting wafer, and the light-transmitting wafer can be a silicon carbide wafer.

[0026] Furthermore, the height difference between the outer ring boss 101 and the inner ring boss 102 is within a first preset range.

[0027] In some embodiments, the first preset range is 1mm to 1.5mm.

[0028] The reason for setting the height difference between the outer ring boss 101 and the inner ring boss 102 within the first preset range is that: large-sized light-transmitting workpieces may be cup-shaped and warped (the warping is usually less than 1mm). When carrying large-sized light-transmitting workpieces, the middle part of the large-sized light-transmitting workpieces may bend slightly towards the chuck under the influence of the workpieces' own weight. Therefore, in order to avoid the large-sized light-transmitting workpieces carried by the outer ring boss 101 from contacting the inner ring boss 102, it is necessary to limit the height difference between the inner ring boss 102 and the outer ring boss 101, that is, to ensure that the height difference between the outer ring boss 101 and the inner ring boss 102 is within the first preset range, so as to avoid the large-sized light-transmitting workpieces from contacting the inner ring boss 102.

[0029] It should be noted that the outer ring boss 101 is used to support and adsorb the light-transmitting workpiece of the first size, and the inner ring boss 102 is used to support and adsorb the light-transmitting workpiece of the second size, wherein the first size is larger than the second size.

[0030] In some embodiments, the second-sized light-transmitting workpiece can be a 4-inch light-transmitting wafer or a 6-inch light-transmitting wafer, and the first-sized light-transmitting workpiece can be an 8-inch light-transmitting wafer or a 12-inch light-transmitting wafer; in other embodiments, the second-sized light-transmitting workpiece can be a 4-inch light-transmitting wafer, a 6-inch light-transmitting wafer, or an 8-inch light-transmitting wafer, and the first-sized light-transmitting workpiece can be a 12-inch light-transmitting wafer.

[0031] In some embodiments, the outer ring boss 101 is annular, and the inner ring boss 102 is annular.

[0032] Furthermore, the material of the body 10 includes aluminum, the light-absorbing layer is black, and the surface roughness of the light-absorbing layer is within a second preset range.

[0033] In some embodiments, the light-absorbing layer is a black nano-coating. In some examples, the light-absorbing layer is a CH99 black nano-coating.

[0034] In some embodiments, the surface roughness Ra of the light-absorbing layer is in the range of 3 μm to 3.5 μm, i.e., the second preset range is 3 μm to 3.5 μm. In some examples, the surface roughness Ra of the light-absorbing layer is 3.2 μm.

[0035] To alleviate the problem of stray light generated when transmitted light is incident on the chuck, the present invention uses an aluminum body 10 and forms a black light-absorbing layer on the body 10, and ensures that the surface roughness of the light-absorbing layer is within a second preset range, so that the light reflected after the transmitted light irradiates the bottom of the cavity 120 has a negligible impact on the detection image, or basically eliminates the reflected light generated after the transmitted light irradiates the bottom of the cavity 120.

[0036] Furthermore, the bearing surface 12 has an adsorption groove 110, and the bottom of the adsorption groove 110 has an adsorption hole. The adsorption hole is used to discharge the air between the adsorption groove 110 and the light-transmitting workpiece to establish a vacuum, thereby realizing the vacuum adsorption of the light-transmitting workpiece. Alternatively, it is used to introduce gas between the adsorption groove 110 and the light-transmitting workpiece to release the vacuum, thereby releasing the vacuum adsorption of the light-transmitting workpiece.

[0037] It should be noted that the number of adsorption grooves 110 on the protrusion can be one or more, for example, 2, 4, 6 or more, and each adsorption groove 110 can have an adsorption hole at the bottom.

[0038] In some embodiments, the outer ring boss 101 has a plurality of adsorption grooves 110 on its bearing surface 12, and the plurality of adsorption grooves 110 are evenly spaced on the bearing surface 12 of the outer ring boss 101; the inner ring boss 102 has a plurality of adsorption grooves 110 on its bearing surface 12, and the plurality of adsorption grooves 110 are evenly spaced on the bearing surface 12 of the inner ring boss 102. It can be understood that the plurality of adsorption grooves 110 evenly spaced on the bearing surface 12 of the boss helps to ensure that the adsorption force on the light-transmitting workpiece is uniform when adsorbing the light-transmitting workpiece, thereby ensuring that the light-transmitting workpiece can be stably adsorbed on the bearing surface 12.

[0039] Furthermore, the cavity 120 includes a first cavity 122 and a second cavity 121. The inner ring boss 102 and the body 10 form the first cavity 122, and the outer ring boss 101, the inner ring boss 102, and the body 10 form the second cavity 121. The bottom surface of the first cavity 122 is flush with the bottom surface of the second cavity 121. Specifically, the outer ring boss 101, the inner ring boss 102, and the body 10 located between the outer ring boss 101 and the inner ring boss 102 form the second cavity 121, and the inner ring boss 102 and the body 10 located inside the inner ring boss 102 form the first cavity 122.

[0040] Furthermore, the first surface 13 has a pick-and-place groove 112, which extends from the edge of the body 10 to the first cavity 122, and the bottom surface of the pick-and-place groove 112 is flush with the bottom surface of the first cavity 122. The pick-and-place groove 112 is used for the robot arm 11 to pick up and place the light-transmitting workpiece. Specifically, when the robot arm 11 places the light-transmitting workpiece on the boss of the chuck, the robot arm 11 can pass through the pick-and-place groove 112 and extend into the first cavity 122. After placing the light-transmitting workpiece on the boss, the robot arm 11 is then pulled out from the pick-and-place groove 112 to complete the placement of the light-transmitting workpiece. When the robot arm 11 removes the light-transmitting workpiece from the chuck, the robot arm 11 can extend from the pick-and-place groove 112 into the first cavity 122 and then raise its height to move the light-transmitting workpiece away from the boss, thereby removing the light-transmitting workpiece.

[0041] Furthermore, the depth of the first cavity 122 is within a third preset range. In some embodiments, the third preset range is 9mm to 11mm. The depth of the first cavity 122 is within the third preset range to ensure that the robot arm 11 will not interfere with the chuck when picking up or placing the light-transmitting workpiece.

[0042] refer to Figure 1 , Figure 3 as well as Figure 4 Furthermore, the chuck also includes a resolution calibration structure 130 and / or an autofocus calibration structure 140, wherein the resolution calibration structure 130 is located on the outside of the boss, and the autofocus calibration structure 140 is located on the outside of the boss. Both the resolution calibration structure 130 and the autofocus calibration structure 140 are fixed to the body.

[0043] Furthermore, the resolution calibration structure 130 includes a first fixing member 131 and a resolution calibration member 132. The first part of the first fixing member 131 is fixed to the first surface 13, and the second part of the first fixing member 131 is located outside the body 10. The resolution calibration member 132 is disposed on the second part of the first fixing member 131, and the top surface of the resolution calibration member 132 is flush with the bearing surface 12 of the outer ring boss 101. And / or, the autofocus calibration structure 140 includes a second fixing member 141 and an autofocus calibration member 142. The first part of the second fixing member 141 is fixed to the first surface 13, and the second part of the second fixing member 141 is located outside the body 10. The autofocus calibration member 142 is disposed on the second part of the second fixing member 141, and the top surface of the autofocus calibration member 142 is flush with the bearing surface 12 corresponding to the outer ring boss 101.

[0044] In some embodiments, the second portion of the first fixing member 131 has a first groove 133, and the resolution calibration member 132 is disposed in the first groove 133. The resolution calibration member 132 is used for calibration and standardization of the optical center.

[0045] In some embodiments, the second part of the second fixing member 141 has a second groove 143, and the autofocus calibration member 142 is disposed in the second groove 143. Since the optical system has a small depth of field (about 10 μm), the system needs to autofocus. Autofocus determines the distance by the energy of reflected light, so it is necessary to set the autofocus calibration member 142 to calibrate the autofocus system to zero.

[0046] In some embodiments, the autofocus calibration element 142 is a light-absorbing blackbody.

[0047] In some embodiments, a through hole may be provided on the second part of the first fixing member 131, and a threaded hole may be provided on the body 10 accordingly. The screw passes through the through hole and is screwed into the threaded hole to install the first fixing member 131 on the body 10. This facilitates the later maintenance and replacement of the resolution calibration structure 130.

[0048] In some embodiments, a through hole may be provided on the second part of the second fixing member 141, and a threaded hole may be provided on the body 10 accordingly. The screw passes through the through hole and is screwed into the threaded hole to install the second fixing member 141 on the body 10. This facilitates the later maintenance and replacement of the autofocus calibration structure 140.

[0049] refer to Figure 1 and Figure 2 Furthermore, the chuck also includes multiple limiting members 111 located on the first surface 13. Each limiting member 111 is located outside the boss and is higher than the boss. The limiting members 111 radially abut against the workpiece to limit its position. The limiting members 111 are designed to ensure that the center of the light-transmitting workpiece is aligned with the center of the chuck when it is placed on the chuck, thus avoiding detection errors.

[0050] In some embodiments, the height difference between the limiting member 111 and the outer ring boss 101 is in the range of 1mm to 1.5mm.

[0051] In some embodiments, a plurality of limiting members 111 are arranged at equal intervals on the outer side of the boss; in some examples, the chuck may include three limiting members 111.

[0052] In some embodiments, the limiting member 111 has a rounded chamfer on the edge facing the workpiece, which is used to guide the center of the workpiece to coincide with the center of the body 10 when the workpiece is placed on the bearing surface 12.

[0053] In some embodiments, the limiting member 111 can be detachably or non-detachably mounted on the body 10 by screwing or gluing. In some embodiments, the limiting member 111 may have a through hole, and the body 10 may have a corresponding threaded hole. A screw passes through the through hole and is screwed into the threaded hole to mount the limiting member 111 on the body 10, thus facilitating the later maintenance and replacement of the limiting member 111. In other embodiments, the limiting member 111 can be bonded and fixed to the body 10 by adhesives such as metal glue or high-temperature glue to ensure stable fixation between the limiting member 111 and the body 10.

[0054] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0055] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A chuck, characterized in that, include: The body has a first surface; A boss is located on the first surface, and the boss and the body form a cavity. The first surface facing the cavity has a light-absorbing layer, and the surface of the boss away from the body is a bearing surface for supporting the light-transmitting workpiece. The boss includes an outer ring boss and an inner ring boss. The outer ring boss is located outside the inner ring boss and is higher than the inner ring boss.

2. The chuck according to claim 1, characterized in that, The height difference between the outer ring boss and the inner ring boss is within a first preset range.

3. The chuck according to claim 1, characterized in that, The material of the body includes aluminum, the light-absorbing layer is black, and the surface roughness of the light-absorbing layer is within a second preset range.

4. The chuck according to claim 1, characterized in that, The bearing surface has an adsorption groove, and the bottom of the adsorption groove has an adsorption hole.

5. The chuck according to claim 1, characterized in that, The cavity includes a first cavity and a second cavity. The inner ring boss and the body form the first cavity, and the outer ring boss, the inner ring boss, and the body form the second cavity.

6. The chuck according to claim 5, characterized in that, The first surface has a pick-and-place groove that extends from the edge of the body to the first cavity, and the bottom surface of the pick-and-place groove is flush with the bottom surface of the first cavity.

7. The chuck according to claim 5 or 6, characterized in that, The depth of the first cavity is within a third preset range.

8. The chuck according to claim 1, characterized in that, The chuck further includes a resolution calibration structure and / or an autofocus calibration structure, wherein the resolution calibration structure is located outside the boss and the autofocus calibration structure is located outside the boss.

9. The chuck according to claim 8, characterized in that, The resolution calibration structure includes a first fixing member and a resolution calibration member. A first part of the first fixing member is fixed to the first surface, and a second part of the first fixing member is located outside the body. The resolution calibration member is disposed on the second part of the first fixing member, and the top surface of the resolution calibration member is flush with the bearing surface of the outer ring boss. Alternatively, the autofocus calibration structure includes a second fixing member and an autofocus calibration member. A first part of the second fixing member is fixed to the first surface, and a second part of the second fixing member is located outside the body. The autofocus calibration member is disposed on the second part of the second fixing member, and the top surface of the autofocus calibration member is flush with the bearing surface corresponding to the outer ring boss.

10. The chuck according to claim 1, characterized in that, The chuck also includes a limiting member located on the first surface. There are multiple limiting members. The limiting members are located outside the boss and are higher than the boss. The limiting members radially abut against the workpiece to limit the position of the workpiece.

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