Wafer adsorption device

Abstract

The utility model provides a wafer adsorption device, which comprises a wafer suction cup, a supporting base body and a machine table gas circuit, negative pressure is generated on the adsorption gas circuit so as to adsorb pores in a wafer suction cup material, negative pressure is further generated on the surface, in contact with a wafer, of the wafer suction cup, and the wafer suction cup material is adsorbed through an inner adsorption area and an outer adsorption area which are arranged in a concentric ring shape. Partitioned adsorption of the wafer with the Taiko ring is achieved, the adsorption strength of the inner adsorption area and the outer adsorption area is adjusted respectively, stress sinking of the middle area of the wafer is slowed down or even avoided, and therefore the problem that a wafer thinning area of the wafer is broken due to stress sinking can be slowed down or even avoided. In addition, the wafer of which the periphery is warped and deformed can be adsorbed in a partitioned manner, and the surface of the wafer of which the periphery is warped is in vacuum fit with the wafer suction cup by adjusting the adsorption force of the inner adsorption area and the outer adsorption area, so that the problem that the subsequent process is influenced due to the fact that the warped wafer cannot be adsorbed is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of wafer fixing devices, in particular to a wafer adsorption device. Background Art

[0002] In the semiconductor manufacturing process, after going through multiple process steps, a large amount of stress will inevitably accumulate on the wafer, resulting in local or overall warping and deformation of the wafer. In addition, the wafer will warp after overall thinning. Currently, power devices and insulated gate bipolar transistors (IGBTs) etc. all require a coating on the back of the wafer. A warped wafer cannot complete the coating well, and it is very difficult to transfer a warped wafer in the electroplating process, greatly increasing the risk of wafer fragmentation and electroplating quality. Therefore, the Taiko process is adopted for this part of the wafers. The Taiko process means that when thinning the wafer, the edge part of the wafer periphery is retained, and only the inner circle of the wafer is ground and thinned. The thinned wafer is in a disc shape. The wafer with the Taiko process has a Taiko ring at the edge for high-strength support and will not warp, and thus can better complete the subsequent backside electroplating process.

[0003] When the existing wafer adsorption device adsorbs a wafer with peripheral warping and deformation, it uses overall adsorption. There will be vacuum leakage between the wafer chuck and the warped wafer, resulting in the inability to adsorb the warped wafer, thus affecting the subsequent processes. In addition, when the existing wafer adsorption device adsorbs a wafer with a Taiko ring, it also uses overall adsorption, which will cause the middle area of the wafer to be stressed and sunken to close to the surface of the adsorption device, so it is easy to cause the wafer to break. Summary of the Utility Model

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present utility model is to provide a wafer adsorption device, which is used to solve the problem that when adsorbing a wafer with peripheral warping and deformation in the prior art, there is vacuum leakage between the wafer chuck and the wafer, resulting in the inability to adsorb the wafer, thus affecting the subsequent processes, and the problem that when overall adsorbing a wafer with a Taiko ring, it is easy to cause the middle area of the wafer to be stressed and sunken, and thus easy to cause the wafer to break.

[0005] To achieve the above purpose and other related purposes, the present utility model provides a wafer adsorption device, which includes: a wafer chuck, a supporting base, and a machine table air circuit;

[0006] The wafer chuck includes an inner adsorption area and an outer adsorption area, the inner adsorption area and the outer adsorption area are arranged in a concentric ring shape, and the inner adsorption area and the outer adsorption area are spaced apart;

[0007] The supporting substrate is used to carry the wafer chuck, and the back surface of the wafer chuck is fixed on the supporting substrate;

[0008] The machine platform air circuit includes several adsorption air circuits and more than two main pipelines. The adsorption air circuits include an outer adsorption air circuit located below the outer adsorption area and an inner adsorption air circuit located below the inner adsorption area;

[0009] Several adsorption air grooves are arranged inside the supporting substrate, and the adsorption air grooves are communicated with the back surface of the wafer chuck. Several of the adsorption air circuits are respectively accommodated in several of the adsorption air grooves. The outer adsorption air circuit and the inner adsorption air circuit are communicated with different main pipelines, so that the machine platform air circuit can independently form negative pressure on the inner adsorption area and the outer adsorption area, and then realize zoned adsorption of the wafer.

[0010] Optionally, the interval distance between the inner adsorption area and the outer adsorption area is 3 mm to 8 mm.

[0011] Optionally, after the outer adsorption air circuit extends out of the adsorption air groove, it is jointly communicated with one of the main pipelines; the inner adsorption air circuit located below the inner adsorption area is jointly communicated with another main pipeline after extending out of the adsorption air groove.

[0012] Optionally, there are more than two of the adsorption air grooves arranged inside the supporting substrate below the outer adsorption area; there are more than two of the adsorption air grooves arranged inside the supporting substrate below the inner adsorption area.

[0013] Further, the adsorption air grooves located below the outer adsorption area are evenly arranged in the supporting substrate below the outer adsorption area; the adsorption air grooves located below the inner adsorption area are evenly arranged in the supporting substrate below the inner adsorption area.

[0014] Optionally, the outer adsorption area and the inner adsorption area of the wafer chuck are concentric circular rings.

[0015] Further, the circular ring of the outer adsorption area of the wafer chuck is divided into several discontinuous arc segments with equal sizes, and each discontinuous arc segment is composed of several identical sub-arc segments arranged at equal intervals.

[0016] Further, it is characterized in that the inner adsorption area extends out a convex area in the radial direction in a direction parallel to the surface of the wafer chuck to increase the adsorption area of the wafer chuck for the wafer, and the convex area is arranged in the area corresponding to the interval between two adjacent arc segments.

[0017] Further, the width of the outer adsorption area of the wafer chuck is 2 mm to 5 mm.

[0018] Optionally, the wafer chuck is made of silicon carbide material with a porous structure.

[0019] As described above, the wafer adsorption device of the present invention has the following beneficial effects: The wafer adsorption device of the present invention generates a negative pressure in the adsorption gas path, thereby adsorbing the pores inside the wafer chuck material, and then generating a negative pressure on the surface where the wafer chuck contacts the wafer. Moreover, through the concentrically arranged inner adsorption area and outer adsorption area, the wafer with a Taiko ring can be adsorbed in a partitioned manner. By adjusting the adsorption forces of the inner adsorption area and the outer adsorption area respectively, the depression of the middle area of the wafer can be slowed down or even avoided, so that the problem of cracking in the wafer thinning area of the wafer caused thereby can be slowed down or even avoided. In addition, the wafer with peripheral warping can also be adsorbed in a partitioned manner. By adjusting the adsorption forces of the inner adsorption area and the outer adsorption area, the surface of the warped wafer can be vacuum-fitted with the wafer chuck, solving the problem that the subsequent process is affected because the warped wafer cannot be adsorbed. Description of the Drawings

[0020] Figure 1 It shows a schematic cross-sectional structure diagram of a wafer with a Taiko ring of the present invention.

[0021] Figure 2 It shows a schematic cross-sectional structure diagram of a wafer adsorption device of the present invention with an outer adsorption area being a ring.

[0022] Figure 3 It shows a schematic cross-sectional structure diagram of a wafer adsorption device of the present invention with an outer adsorption area being an arc segment.

[0023] Figure 4 It shows that when the wafer adsorption device of the present invention adsorbs a wafer with a Taiko ring and there is a depression inside the wafer, the wafer is along the Figure 1 direction of BB' in Figure 2 and the wafer adsorption device is along the direction of AA' in

[0024] Figure 5 Figure 1 schematic cross-sectional structure diagram. Figure 2 schematic cross-sectional structure diagram.

[0025] Description of Component Labels

[0026] 1 Wafer chuck

[0027] 10 Inner adsorption area

[0028] 11 Outer adsorption area

[0029] 110 arc segment

[0030] 111 Region corresponding to the interval between two adjacent arc segments

[0031] 112 sub-arc segment

[0032] 113 convex region

[0033] 2 supporting substrate

[0034] 3 machine platform gas path

[0035] 30 main pipeline

[0036] 301 first main pipeline

[0037] 300 second main pipeline

[0038] 31 adsorption gas path

[0039] 310 internal adsorption gas path

[0040] 311 external adsorption gas path

[0041] 4 wafer

[0042] 40 wafer thinning region

[0043] 41 Taiko ring region Detailed implementation manners

[0044] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0045] Please refer to Figures 1 to 5 . It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have technical essence. Any modification of the structure, change of the ratio relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of clear description and are not used to limit the scope for the implementation of the present invention. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope for the implementation of the present invention.

[0046] As described in the background art, after the Taiko process, the edge part of the wafer periphery is retained, and only the inner circle of the wafer is ground and thinned. As an example, as Figure 1 shown in a wafer 4 with a Taiko ring, the wafer 4 includes a wafer thinning area 40 and a Taiko ring area 41. The inner area 40 of the wafer is thinned. When the wafer adsorption device in the prior art adsorbs the wafer with a Taiko ring, it uses overall adsorption, which will cause the middle area of the wafer to be sunken by force to be close to the surface of the adsorption device. Therefore, it is easy to cause the wafer thinning area 40 of the wafer 4 to rupture due to force deformation, especially the adjacent area between the wafer thinning area 40 and the Taiko ring area 41 has a larger deformation amount and is more likely to rupture. In addition, when adsorbing a wafer with peripheral warping deformation in the prior art, there is a vacuum leak between the wafer chuck and the wafer, resulting in the wafer not being adsorbed.

[0047] Based on this, as Figures 2 to 5 shown, the present invention provides a wafer adsorption device, which includes: a wafer chuck 1, a supporting base 2 and a machine table air circuit 3;

[0048] The wafer chuck 1 includes an inner adsorption area 10 and an outer adsorption area 11. The inner adsorption area 10 and the outer adsorption area 11 are arranged in a concentric ring shape, and the inner adsorption area 10 and the outer adsorption area 11 are arranged at intervals;

[0049] The supporting base 2 is used to carry the wafer chuck 1, and the back surface of the wafer chuck 1 is fixed on the supporting base 2;

[0050] The machine table air circuit 3 includes a plurality of adsorption air circuits 31 and two or more main pipelines 30. The adsorption air circuit 31 includes an outer adsorption air circuit 311 located below the outer adsorption area 11 and an inner adsorption air circuit 310 located below the inner adsorption area 10;

[0051] A plurality of adsorption air grooves are arranged inside the supporting base 2. The adsorption air grooves are communicated with the back surface of the wafer chuck 1. A plurality of the adsorption air circuits 31 are respectively accommodated in a plurality of the adsorption air grooves. The outer adsorption air circuit 311 and the inner adsorption air circuit 310 are communicated with different main pipelines 30, so that the machine table air circuit 3 can independently form a negative pressure on the inner adsorption area 10 and the outer adsorption area 11, and then realize zoned adsorption of the wafer 4.

[0052] The wafer adsorption device in this embodiment generates a negative pressure in the adsorption gas path, thereby adsorbing the pores inside the wafer chuck material, and then generating a negative pressure on the surface where the wafer chuck contacts the wafer. Moreover, through the inner adsorption area and the outer adsorption area arranged in a concentric ring shape, the wafer with a Taiko ring is adsorbed in a partitioned manner. By adjusting the adsorption forces of the inner adsorption area and the outer adsorption area respectively, the depression of the middle area of the wafer due to stress can be slowed down or even avoided. Therefore, the problem of cracking in the wafer thinning area of the wafer caused thereby can be slowed down or even avoided. In addition, the wafer with peripheral warping deformation can also be adsorbed in a partitioned manner. By adjusting the adsorption forces of the inner adsorption area and the outer adsorption area, the surface of the peripherally warped wafer can be vacuum-fitted with the wafer chuck, solving the problem that the subsequent process is affected because the warped wafer cannot be adsorbed.

[0053] As Figure 4 and Figure 5 shown, the outer adsorption gas path 311 is located below the outer adsorption area 11, and the inner adsorption gas path 310 is located below the inner adsorption area 10. The outer adsorption gas path 311 and the inner adsorption gas path 310 can be independently controlled to form a negative pressure. As an example, after the outer adsorption gas path 311 extends from the adsorption gas groove, it can be commonly connected to the same main pipeline 30 or separately connected to multiple main pipelines 30. The inner adsorption gas path 310 can be commonly connected to the same main pipeline 30 or separately connected to multiple main pipelines 30 after extending from the adsorption gas groove. Here, the main pipeline 30 connected by the outer adsorption gas path 311 is different from the main pipeline 30 connected by the inner adsorption gas path 310. In this embodiment, an example is given where the outer adsorption gas path 311 extends from the adsorption gas groove and is commonly connected to a first main pipeline 301, and the inner adsorption gas path 310 extends from the adsorption gas groove and is commonly connected to a second main pipeline 300.

[0054] As Figure 4 shown, when adsorbing the wafer 4 with a Taiko ring, a larger adsorption force is set for the first main pipeline 301 to separately adsorb the Taiko ring area 41, and a smaller adsorption force is set for the second main pipeline 300 to separately adsorb the wafer thinning area 40, so as to slow down the degree of depression of the middle area 40 of the wafer due to stress, especially reducing the deformation amount of the adjacent area between the wafer thinning area 40 and the Taiko ring area 41. Therefore, the problem of cracking in the wafer thinning area 40 of the wafer 4 caused thereby is reduced or even avoided.

[0055] As Figure 5As shown, a greater adsorption force is set for the first main pipeline 301 to separately adsorb the Taiko ring area 41, and the second main pipeline 300 does not adsorb the wafer thinning area 40 of the wafer, further slowing down or even avoiding the depression of the middle area 40 of the wafer due to stress, thus avoiding the problem of cracking of the wafer thinning area 40 of the wafer 4 caused thereby. In addition, compared with the existing wafer adsorption device, this setting requires less modification to the machine tool, is easy to operate, and has a high adsorption efficiency.

[0056] In other embodiments, the outer adsorption gas path 311 located below the outer adsorption area 11 can be set to communicate with a plurality of the main pipelines 30 respectively after extending from the adsorption gas groove, and the inner adsorption gas path 310 located below the inner adsorption area 10 can be set to communicate with a plurality of the main pipelines 30 respectively after extending from the adsorption gas groove, so as to perform a more refined partition adsorption control on the wafer. As an example, in order to address the problem that the deformation amount of the area adjacent to the wafer thinning area 40 and the Taiko ring area 41 is larger and more likely to crack during wafer adsorption, separate adsorption can be set for the area adjacent to the wafer thinning area 40 and the Taiko ring area 41, and a smaller adsorption force can be set to slow down the deformation of the wafer in the area adjacent to the wafer thinning area 40 and the Taiko ring area 41, reducing or even avoiding the problem of wafer cracking caused thereby. In order to address the problem of warped wafer deformation, separate adsorption can be set for the area where the warped wafer is prone to warping, and a greater adsorption force can be set for the warped area, so that the surface of the warped wafer is vacuum-fitted with the wafer chuck, solving the problem that the subsequent process is affected because the warped wafer cannot be adsorbed.

[0057] The adsorption gas groove inside the supporting base 2 is communicated with the back surface of the wafer chuck 1. The adsorption gas path 31 is accommodated in the adsorption gas groove and contacts the back surface of the wafer chuck 1. The wafer adsorption device generates negative pressure on the adsorption gas path 31, thereby adsorbing the pores inside the material of the wafer chuck 1, and then generating negative pressure on the surface of the wafer chuck 1 in contact with the wafer 4 to complete the adsorption of the wafer 4.

[0058] As an example, such as Figure 4As shown, the number and the arrangement positions of the adsorption air grooves provided inside the supporting base body 2 located below the wafer suction cup 1 can be adjusted according to requirements. Preferably, in this embodiment, there are more than two adsorption air grooves provided inside the supporting base body 2 located below the outer adsorption area 11; there are more than two adsorption air grooves provided inside the supporting base body 2 located below the inner adsorption area 10, and the adsorption air grooves located below the outer adsorption area 11 are evenly arranged inside the supporting base below the outer adsorption area 11; the adsorption air grooves located below the inner adsorption area 10 are evenly arranged inside the supporting base below the inner adsorption area 10, which is used to improve the adsorption force per unit area of the Taiko ring area 41 and perform uniform adsorption on the wafer thinning area 40 and the Taiko ring area 41 of the wafer 4 respectively.

[0059] The wafer suction cup 1 is made of a material with loose pores and certain mechanical strength. As an example, the wafer suction cup 1 can be made of loose porous silicon carbide material, and this material can be prepared by methods including but not limited to the template method, the foam coprecipitation method or adding pore-forming agents, etc. This material can prepare a pore structure with controllable porosity and pore size, and has corrosion resistance and good chemical stability.

[0060] When the adsorption air path 31 adsorbs the pores of the loose porous material inside the wafer suction cup 1, the adsorption air path 31 inside the adsorption air groove mainly adsorbs the wafer suction cup 1 in the direction perpendicular to the surface of the wafer suction cup 1 upward, and has little influence on its surrounding area. However, in order to more precisely control the zoned adsorption, the inner adsorption area 10 and the outer adsorption area 11 are arranged at intervals, and the interval distance between the outer adsorption area 11 and the inner adsorption area 10 can be adjusted according to requirements. As an example, the interval distance between the inner adsorption area 10 and the outer adsorption area 11 can be 3 mm to 8 mm to complete more precise zoned adsorption.

[0061] The shapes of the outer adsorption area 11 and the inner adsorption area 10 can be adjusted according to requirements. As an example, as Figure 2 shown, the outer adsorption area 11 of the wafer suction cup 1 is a concentric circular ring with the inner adsorption area 10. The width of the outer adsorption area 11 of the wafer suction cup 1 can be adjusted according to the width of the Taiko ring area 41. As an example, the width of the outer adsorption area 11 of the wafer suction cup 1 can be set to 2 mm to 5 mm, so that the outer adsorption area 11 corresponds to the Taiko ring area 41, and the inner adsorption area 10 corresponds to the wafer thinning area 40, thereby accurately realizing the zoned adsorption of most wafers 4 processed by the Taiko process.

[0062] As an example, asFigure 3 As shown, the ring of the outer adsorption area 11 of the wafer chuck 1 is divided into a number of discontinuous arc segments 110 of equal size. Each discontinuous arc segment 110 is composed of a number of identical sub-arc segments 112 arranged at equal intervals. And the inner adsorption area 10 extends a protruding area 113 radially in a direction parallel to the surface of the wafer chuck 1 to increase the adsorption area of the wafer chuck 1 for the wafer 4. The protruding area 113 is arranged in the area 111 corresponding to the interval between two adjacent arc segments. Preferably, in this embodiment, the ring of the outer adsorption area 11 of the wafer chuck 1 is divided into 3 discontinuous arc segments 110 of equal size. Each discontinuous arc segment 110 is composed of 5 identical sub-arc segments 112 arranged at equal intervals. At least one adsorption air groove is arranged inside the supporting base body 2 below each sub-arc segment 112. And the adsorption air paths 31 arranged below each sub-arc segment 112 are respectively communicated with independent main pipelines 30 after extending from the adsorption air grooves. It can not only be used for zonal adsorption of the wafer 4 with a Taiko ring, but also be used for more precise zonal adsorption of a warped wafer with the arc segments 110 as the zonal units.

[0063] In summary, the present invention provides a wafer adsorption device. By generating negative pressure in the adsorption air paths, the pores inside the wafer chuck material are adsorbed, and then negative pressure is generated on the surface where the wafer chuck contacts the wafer. And through the concentrically arranged inner adsorption area and outer adsorption area, zonal adsorption of the wafer with a Taiko ring is realized. By adjusting the adsorption forces of the inner adsorption area and the outer adsorption area respectively, the depression of the middle area of the wafer due to stress is slowed down or even avoided. Therefore, the problem of cracking in the wafer thinning area of the wafer caused thereby can be slowed down or even avoided. In addition, zonal adsorption can also be carried out on the wafer with warped periphery. By adjusting the adsorption forces of the inner adsorption area and the outer adsorption area, the surface of the warped wafer at the periphery is vacuum-fitted with the wafer chuck, solving the problem that the subsequent process is affected because the warped wafer cannot be adsorbed. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0064] The above embodiments are only illustrative of the principles and effects of the present invention, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A wafer adsorption device, characterized in that: The wafer adsorption device comprises: a wafer suction cup, a supporting base and a machine gas path; The wafer suction cup comprises an inner suction area and an outer suction area, the inner suction area and the outer suction area are arranged in a concentric ring shape, and the inner suction area and the outer suction area are arranged at intervals; The supporting base is used to carry the wafer suction cup, and the back side of the wafer suction cup is fixed on the supporting base; The machine gas circuit includes a plurality of adsorption gas circuits and two or more main circuits, and the adsorption gas circuit includes an outer adsorption gas circuit located below the outer adsorption area and an inner adsorption gas circuit located below the inner adsorption area; A plurality of adsorption gas grooves are arranged inside the supporting base, and the adsorption gas grooves are connected with the back side of the wafer suction cup. A plurality of adsorption gas paths are accommodated in the plurality of adsorption gas grooves in a one-to-one correspondence. The external adsorption gas path and the internal adsorption gas path are connected with different main paths, so that the machine gas path can independently form negative pressure for the internal adsorption area and the external adsorption area, thereby realizing zoned adsorption of the wafer.

2. The wafer adsorption device according to claim 1, characterized in that: The inner adsorption area and the outer adsorption area are spaced apart by a distance of 3 mm to 8 mm.

3. The wafer adsorption device according to claim 1, characterized in that: The external adsorption gas path extends from the adsorption gas tank and is connected to the main path; The inner adsorption gas path located below the inner adsorption zone extends from the adsorption gas groove and is connected to another main path.

4. The wafer adsorption device according to claim 1, characterized in that: More than two adsorption gas grooves are arranged inside the supporting base below the outer adsorption zone; more than two adsorption gas grooves are arranged inside the supporting base below the inner adsorption zone.

5. The wafer adsorption device according to claim 4, characterized in that: The adsorption gas grooves located below the outer adsorption zone are evenly arranged in the supporting base below the outer adsorption zone; the adsorption gas grooves located below the inner adsorption zone are evenly arranged in the supporting base below the inner adsorption zone.

6. The wafer adsorption device according to claim 1, characterized in that: The outer adsorption area and the inner adsorption area of ​​the wafer suction cup are in the shape of concentric rings.

7. The wafer adsorption device according to claim 6, characterized in that: The circular ring of the outer adsorption area of ​​the wafer suction cup is divided into a plurality of discontinuous arc segments of equal size, and each of the discontinuous arc segments is composed of a plurality of identical sub-arc segments arranged at equal intervals.

8. The wafer adsorption device according to claim 7, characterized in that: The inner adsorption zone radially extends a protruding area in a direction parallel to the surface of the wafer suction cup to increase the adsorption area of ​​the wafer suction cup on the wafer, and the protruding area is arranged in an area corresponding to the interval between two adjacent arc segments.

9. The wafer adsorption device according to any one of claims 1 to 8, characterized in that: The width of the outer adsorption area of ​​the wafer chuck is 2 mm to 5 mm.

10. The wafer adsorption device according to claim 1, characterized in that: The wafer suction cup is made of silicon carbide material with a loose porous structure.

Images