Wafer ring taking device and ring taking method

Abstract

The embodiment of the invention provides a wafer ring taking device and a ring taking method. The ring taking device carries out ring taking operation on a wafer. The wafer comprises a thinned wafer main body and a thinning ring surrounding the thinned wafer main body; the wafer ring taking device comprises a ring taking unit which is used for separating a thinned wafer main body and a thinned ring and taking down the thinned ring; the scanning unit is used for determining the position of a wafer base for placing a wafer and the first relative position of the thinning ring relative to the center of the wafer base; the calculation unit is used for calculating a second relative position of the circle center of the thinned wafer main body relative to the center of the wafer base according to the first relative position and the position of the wafer base; and the control unit is used for adjusting the relative position of the ring taking unit and the thinned ring according to the second relative position and controlling the ring taking unit. By adopting the wafer ring taking device and the ring taking method, the risk that the wafer is scratched by the ring taking unit can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a wafer ring removal device and a ring removal method. Background Art

[0002] In order to improve the heat dissipation efficiency of the chip, reduce the chip packaging volume, reduce the internal stress of the chip, and improve the electrical performance, the wafer needs to be thinned. The wafer thinning process does not thin the entire plane of the wafer, but only thins the middle part of the wafer. The edge of the wafer is not thinned. The edge of the wafer that is not thinned forms a thinning ring, which is removed by the ring removal unit.

[0003] However, during the ring removal process, there is a problem that the wafer is scratched by the ring removal unit. Therefore, how to provide a technical solution to reduce the risk of the wafer being scratched by the ring removal unit has become a technical problem that technicians in this field need to solve urgently. Summary of the invention

[0004] The technical problem solved by the present invention is to reduce the risk of the wafer being scraped by the ring removing unit by providing a wafer ring removing device and a ring removing method.

[0005] In order to solve the above problems, an embodiment of the present invention provides a wafer ring removal device, which performs a ring removal operation on the wafer; the wafer includes: a thinned wafer body and a thinning ring surrounding the thinned wafer body; the wafer ring removal device includes: a ring removal unit, used to separate the thinned wafer body and the thinning ring, and remove the thinning ring; a scanning unit, used to determine the position of a wafer base for placing the wafer, and a first relative position of the thinning ring relative to the center of the wafer base; a calculation unit, used to calculate the second relative position of the center of the thinned wafer body relative to the center of the wafer base according to the first relative position and the position of the wafer base; a control unit, which adjusts the relative position of the ring removal unit and the thinning ring according to the second relative position, and controls the ring removal unit.

[0006] Optionally, the ring removal device comprises: a bracket capable of moving relative to the wafer base;

[0007] The ring removal unit comprises:

[0008] A ring-taking gripper capable of grasping the thinned ring;

[0009] At least three first connecting rods, one end of each first connecting rod is movably connected to the bracket, and the other end of each first connecting rod is rotatably connected to a ring removal clamp;

[0010] Wherein, the first connecting rods surround the bracket and are evenly distributed.

[0011] Optionally, the scanning unit includes:

[0012] a second connecting rod, one end of which is movably connected to the bracket;

[0013] an optical sensor connected to the other end of the second connecting rod and used to obtain the position of the thinning ring;

[0014] Wherein, the light sensor is coupled to the computing unit.

[0015] Optionally, the ring removal device further comprises:

[0016] Coarse alignment unit;

[0017] The coarse alignment unit comprises:

[0018] a third connecting rod, one end of which is connected to the bracket;

[0019] A coarse alignment clamp is connected to the other end of the third connecting rod and is used to place the wafer on the wafer base so that the distance between the center of the wafer and the center of the wafer base is within a preset alignment error.

[0020] Optionally, the cross-sectional shape of the ring removal clamp on a plane perpendicular to the wafer base is in the shape of an I.

[0021] Optionally, the ring removal device further comprises:

[0022] The contact end between the ring-removing clamp and the thinned ring includes one or more of a square cylinder, a round cylinder, an elliptical cylinder, and a cone.

[0023] Optionally, the ring removal device further comprises:

[0024] Circular cutting tape, used to stick crystal circles;

[0025] A ring-cut tape frame for removing the ring-cut tape, the ring-cut tape frame being located on an edge region of the ring-cut tape;

[0026] The bonded wafer is located on the central area of ​​the circular cutting tape and is spaced apart from the circular cutting tape frame.

[0027] Optionally, the ring removing unit further includes: a pressure sensing module, which is arranged on the ring removing clamps in a one-to-one correspondence and is used to test the force exerted by the ring removing clamps on the wafer.

[0028] Optionally, the ring removal device further includes: a motor coupled to the coarse alignment jaw and the ring removal jaw, and the control unit controls the motor to drive the coarse alignment jaw and the ring removal jaw to move.

[0029] Accordingly, an embodiment of the present invention further provides a wafer ring removal method, which is applied to a wafer ring removal device; the wafer comprises: a thinned wafer body and a thinning ring surrounding the thinned wafer body;

[0030] The wafer ring removal device comprises:

[0031] Ring taking unit, scanning unit, calculation unit, control unit;

[0032] The ring removal method comprises:

[0033] Adsorbing the wafer with the dicing tape bonded thereto onto a wafer base;

[0034] Using the scanning unit, determining the position of a wafer base for placing the wafer and a first relative position of the thinning ring relative to the center of the wafer base;

[0035] Using the calculation unit, according to the first relative position and the position of the wafer base, calculate the second relative position of the center of the thinned wafer body relative to the center of the wafer base;

[0036] The control unit is used to adjust the relative position of the ring removing unit and the thinning ring according to the second relative position, and control the ring removing unit to separate the thinned wafer body and the thinning ring, and remove the thinning ring.

[0037] Optionally, the wafer ring removal device further includes: a rough alignment unit;

[0038] The coarse alignment unit comprises: a coarse alignment clamping jaw;

[0039] Before the step of placing the wafer with the ring cutting tape bonded thereto on the wafer base, the ring removal method further comprises:

[0040] The control unit is used to adjust the positions of the wafer and the wafer base through the coarse alignment clamps of the coarse alignment unit, so that the distance between the center of the wafer and the center of the wafer base is within a preset alignment error.

[0041] Compared with the prior art, the technical solution of this embodiment has the following advantages:

[0042] The wafer ring removal device described in the present invention is used to perform a ring removal operation on a wafer; the wafer includes: a thinned wafer body and a thinning ring surrounding the thinned wafer body; the wafer ring removal device includes: a ring removal unit, a scanning unit, a calculation unit, and a control unit; the calculation unit calculates the second relative position of the center of the thinned wafer body relative to the center of the wafer base based on the position and the first relative position of the wafer base obtained by the scanning unit, that is, calculates the offset between the center of the thinned wafer body and the center of the wafer base; the control unit adjusts the relative position of the ring removal unit and the thinning ring according to the offset, controls the ring removal unit to remove the ring, and reduces the risk of the ring removal unit scratching the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0044] Figure 1 It is a structural schematic diagram of a ring removal device;

[0045] Figure 2 The present invention is a schematic diagram of a process flow corresponding to the ring removal by a ring removal device;

[0046] Figures 3 to 9 It is a schematic structural diagram corresponding to a wafer ring removal device according to an embodiment of the present invention;

[0047] Fig.10 It is a flow chart of a ring removal method corresponding to a wafer ring removal device according to an embodiment of the present invention;

[0048] Fig.11 is a schematic diagram of the positional relationship between the center of a wafer and the center of a wafer substrate according to an embodiment of the present invention;

[0049] Fig.12 It is a schematic diagram of separating the thinned wafer body from the thinned ring after the ring is removed by the wafer ring removal device according to one embodiment of the present invention. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0051] As known from the background technology, in the process of removing the ring, there is a problem that the wafer is scratched by the ring removing unit. Figure 1 The wafer ring removal device is used to analyze the reasons why the wafer is scratched.

[0052] refer to Figure 1 , which is a structural schematic diagram of a ring removal device; the wafer ring removal device includes: a carrier 101, a suction hole 102 located on the carrier; a ring removal clamp 106, and the ring removal clamp 106 includes a first clamp 107 and a second clamp 108; the relative position of the ring removal clamp 106 and the carrier 101 is fixed.

[0053] The wafer 103 includes a thinned wafer body 104 and a thinning ring 105 separated from the thinned wafer body 104 . The mark 109 is a boundary after the thinned wafer body 104 and the thinning ring 105 are separated.

[0054] refer to Figure 2 , is a schematic diagram of a process flow corresponding to ring removal by a ring removal device; the ring removal steps of the wafer ring removal device are as follows:

[0055] Step S01: placing a wafer on a carrier.

[0056] The wafer ring 103 to be removed is placed on the carrier 101 , and the relative position of the wafer ring 103 to be removed and the carrier 101 is manually adjusted. Then, the thinned wafer body 104 of the wafer ring 103 to be removed is adsorbed on the carrier 101 through the adsorption holes 102 on the carrier 101 .

[0057] Step S02: The ring-removing jaws remove the thinned ring.

[0058] The side wall of the thinned ring 105 is clamped by the first clamping jaw 107 and the second clamping jaw 108 of the ring removing clamping jaw 106 , and the thinned ring 105 is removed from the wafer 103 .

[0059] During the above-mentioned manufacturing process, the wafer 103 to be removed is manually placed on the stage 101, and the relative position of the wafer 103 to be removed and the stage 101 is manually adjusted. There is a situation where the relative position deviation of the wafer 103 to be removed and the stage 101 is relatively large. Since the relative position of the ring removal jaws 106 and the stage 101 is fixed, the first jaw 107 and the second jaw 108 will touch the surface of the thinned ring 105, causing the thinned ring 105 to be scratched and unable to be removed, or the first jaw 107 or the second jaw 108 will touch the surface of the thinned wafer body 104, causing the thinned wafer body 104 to be scratched.

[0060] In view of the above technical problems, an embodiment of the present invention provides a wafer ring removal device, which can reduce the risk of the ring removal unit scratching the wafer during the ring removal process.

[0061] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the following will be combined with the embodiments of the present invention. Figures 3 to 9 , the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0062] refer to Figures 3 to 9 , is a schematic structural diagram corresponding to a wafer ring removal device according to an embodiment of the present invention.

[0063] The wafer ring removal device described in the present embodiment performs a ring removal operation on the wafer; the wafer includes: a thinned wafer body and a thinning ring surrounding the thinned wafer body; the wafer ring removal device includes: a ring removal unit, used to separate the thinned wafer body and the thinning ring, and remove the thinning ring; a scanning unit, used to determine the position of a wafer base for placing the wafer, and a first relative position of the thinning ring relative to the center of the wafer base; a calculation unit, used to calculate the second relative position of the center of the thinned wafer body relative to the center of the wafer base according to the first relative position and the position of the wafer base; a control unit, which adjusts the relative position of the ring removal unit and the thinning ring according to the second relative position, and controls the ring removal unit.

[0064] When the wafer ring removal device described in the present invention is used to remove the ring, the calculation unit calculates the second relative position of the center of the thinned wafer body with respect to the center of the wafer base according to the position of the wafer base and the first relative position obtained by the scanning unit, that is, calculates the offset between the center of the thinned wafer body and the center of the wafer base; the control unit adjusts the relative position of the ring removal unit and the thinning ring according to the offset, controls the ring removal unit to remove the ring, and reduces the risk of the ring removal unit scratching the wafer.

[0065] refer to Figure 3 The wafer includes: a thinned wafer body 201 and a thinning ring 202 surrounding the thinned wafer body 201 .

[0066] It should be noted that Figure 3 Marks E3 and E4 in FIG. 2 are the boundaries after the thinned wafer body 201 and the thinning ring 202 are separated.

[0067] A plurality of semiconductor devices (not shown) are distributed on the thinned wafer body 201 ; the thinning ring 202 surrounds the thinned wafer body 201 to enhance the strength of the thinned wafer body 201 and reduce the risk of the thinned wafer body 201 breaking during the transfer process.

[0068] refer to Figure 4 , combined with Figure 3 The ring removal device includes: a bracket 300 that can move relative to the wafer base 301; the bracket 300 is used to carry the ring removal unit 303 and the rough alignment unit 400. Figure 4 For a detailed description of the ring removal unit 303 and the coarse alignment unit 400, please refer to the following.

[0069] The number of the bracket 300 is at least 1; the material of the bracket 300 includes: metal material (such as stainless steel, aluminum, etc.) or anti-static plastic material (such as polycarbonate, electro-polypropylene, acrylic, etc.); the bracket 300 is composed of a column structure, and the column structure includes any of the following: a cylindrical structure, an elliptical cylindrical structure, a square cylindrical structure, etc. The embodiment of the present application does not limit the number, material and specific main structure of the bracket 300, and those skilled in the art can adjust the settings according to actual conditions. It should be noted that in order to make the drawings concise, clear, and convenient for description, in this embodiment, the number of the bracket 300 is 1, the material of the bracket 300 is metal, and the bracket 300 is a cylindrical structure.

[0070] The support 300 includes: an area 500, an area 501, and an area 503. The ring removal unit 303 is connected to the area 500 of the support 300, and the rough alignment unit 400 is connected to the area 501 of the support 300.

[0071] It should be noted that, for the sake of clarity of the drawings and convenience of description, the present invention sets the area 500, area 501, and area 503. In other embodiments, the area 500, area 501, and area 503 may not be set.

[0072] In this embodiment, the region 503 of the support 300 is parallel to the surface of the wafer, and the region 500 and the region 501 are perpendicular to the region 503 .

[0073] The support can move relative to the wafer base, that is, in this embodiment, the support 300 can move relative to the wafer base 301 .

[0074] It should be noted that, in some embodiments, the wafer base 301 is fixed, and the support 300 can move in a direction parallel to the surface of the wafer base 301, such as forward and backward, and can move perpendicular to the surface of the wafer base 301, such as forward and backward; in another embodiment, the support 300 is fixed, and the wafer base 301 can move in a direction parallel to the region 503 of the support 300, such as forward and backward, and can also move perpendicular to the region 503 of the support 300, such as forward and backward; in other embodiments, the wafer base 301 and the support 300 can move simultaneously, for example: when the wafer base 301 moves toward the support 300, the support 300 can move away from or close to the wafer base 301. For another example: when the support 300 moves toward the wafer base 301, the wafer base 301 can move away from or close to the support 300. In this embodiment, the wafer base 301 is fixed, and the bracket 300 can move relative to the wafer base 301, that is, the bracket 300 can move forward and backward in a direction perpendicular to the surface of the wafer base 301, and can also move forward and backward in a direction parallel to the surface of the wafer base 301.

[0075] Continue to refer Figure 3 , the wafer base 301 is used to carry the thinned wafer body 201;

[0076] The material of the wafer base 301 includes: metal material (such as stainless steel, aluminum, etc.) or anti-static plastic material (such as polycarbonate, electro-polypropylene, acrylic, etc.); the wafer base 301 is a columnar structure, and the columnar structure includes any of the following: a cylindrical structure, an elliptical cylindrical structure, a square cylindrical structure, etc. The embodiment of the present application does not limit the material and specific columnar structure of the wafer base 301, and those skilled in the art can adjust the settings according to actual conditions. In this embodiment, the material of the wafer base 301 is metal, and the wafer base 301 is a cylindrical structure.

[0077] The carrier 302 is used to carry the wafer base 301, the circular cutting tape and the circular cutting tape frame.

[0078] The wafer ring removal device comprises: a ring removal unit, which is used to separate the thinned wafer body and the thinning ring, and remove the thinning ring.

[0079] The ring removal unit includes: a ring removal claw capable of grabbing the thinned ring; at least three first connecting rods, one end of each first connecting rod is movably connected to the bracket, and the other end of each first connecting rod is rotatably connected to a ring removal claw; wherein the first connecting rods surround the bracket and are evenly distributed.

[0080] It should be noted that the ring removing unit can move on the bracket in a radial direction parallel to the wafer, or can move perpendicular to the surface direction of the wafer.

[0081] refer to Figure 5 and Figure 6 , combined with Figure 3 and Figure 4 The ring removing unit 303 includes: a ring removing jaw, and the ring removing jaw is capable of grabbing the thinned ring 202.

[0082] The number of the ring removal jaws is at least 3. In this embodiment, the number of the ring removal jaws is 3, namely, the ring removal jaw 304, the ring removal jaw 305, and the ring removal jaw 306. Figure 6 shown.

[0083] The cross-sectional shape of the ring-removing clamp on a plane perpendicular to the wafer base is in an "I" shape.

[0084] In this embodiment, the cross-sectional shapes of the ring removing jaws 304 , 305 , and 306 on a plane perpendicular to the wafer base 301 are all in the shape of an I.

[0085] For the sake of simplicity and convenience of description, Figure 3 and Figure 5 Only the ring removal clamping jaws 304 and 305 are shown, but the present invention is not limited thereto.

[0086] The cross-section of the ring-removing clamp on a plane perpendicular to the wafer base includes a separated first layer, a second layer and a connecting member, and the connecting member vertically connects the first layer and the second layer; wherein the width of the first layer and / or the second layer that can contact the thinning ring is [1 / 3, 1) of the width of the thinning ring.

[0087] It should be noted that the width of the first layer and / or the second layer that can contact the thinning ring is [1 / 3, 1) of the width of the thinning ring, which includes the following three meanings: the first type: the width of the first layer and the second layer that can contact the thinning ring is both [1 / 3, 1) of the width of the thinning ring; the second type: the width of the first layer that can contact the thinning ring is [1 / 3, 1) of the width of the thinning ring; the third type: the width of the second layer that can contact the thinning ring is [1 / 3, 1) of the width of the thinning ring.

[0088] Continue to refer Figure 3 , Figure 4 and Figure 5In this embodiment, the ring-removing jaw 304 is taken as an example for description. For other ring-removing jaws, reference may be made to the description of the ring-removing jaw 304. The cross-section of the ring-removing jaw 304 on a plane perpendicular to the wafer base 301 includes a separated first layer 307, a second layer 308 and a connector 309, and the connector 309 vertically connects the first layer 307 and the second layer 308; wherein the width w1 of the first layer 307 and / or the second layer 308 that can contact the thinning ring 202 is [1 / 3, 1] of the width w2 of the thinning ring 202.

[0089] It should be noted that the width w1 of the contact between the first layer 307 and the thinning ring 202 is greater than or equal to 1 / 3 times the width w2 of the thinning ring 202, which reduces the risk of the thinning ring 202 slipping off the first layer 307 during the ring removal process; the width w1 of the contact between the first layer 307 and the thinning ring 202 is less than 1 times the width w2 of the thinning ring 202, which reduces the risk of the ring removal claws hitting the thinning ring 202 during the ring removal process.

[0090] It should be noted that the width w3 that the second layer 308 can contact with the thinned ring 202 is greater than or equal to 1 / 3 times the width w2 of the thinned ring 202. During the ring removal process, the thinned ring 202 is prevented from bouncing off the first layer 307. The width w3 that the second layer 308 can contact with the thinned ring 202 is less than 1 times the width of the thinned ring 202. During the ring removal process, the risk of the second layer 308 hitting the thinned ring 202 is reduced. During the ring removal process, the second layer 308 can control the thinned ring 202 to be located between the first layer 307 and the second layer 308.

[0091] In this embodiment, the width w4 of the first layer 307 and the width w4 of the second layer 308 are equal.

[0092] The connection position between the connecting member 309 and the first layer 307 and the second layer 308 is the geometric center of the first layer 307 and the second layer 308 , which helps to prevent the ring removal clamp from being eccentric when rotating around the area 500 of the bracket 300 .

[0093] The contact end between the ring-removing clamp and the thinned ring includes one or more of a square cylinder, a round cylinder, an elliptical cylinder, and a cone.

[0094] refer to Figure 7 , combined with Figure 6 , Figure 7 include Figure 7 (a) Figure 7 (b) Figure 7 (c) and Figure 7 (d).

[0095] like Figure 7 As shown in (a), the first layer 307 of the ring removal clamp is in the form of a square column with the contact end 310 of the thinned ring 202.

[0096] like Figure 7 As shown in (b), the first layer 307 of the ring removing jaws is cone-shaped, i.e., pointed-end-shaped, with the contact end 310 of the thinning ring 202. When removing the ring, it is convenient for the pointed end of the first layer 307 to enter the gap between the thinning ring 202 and the ring-cutting tape, which is beneficial to separating the thinning ring 202 and the ring-cutting tape.

[0097] like Figure 7 As shown in (c), the first layer 307 of the ring-removing clamp is a circular cylinder or an elliptical cylinder, that is, an arc-shaped protrusion, which facilitates the arc-shaped protrusion of the first layer 307 to enter the gap between the thinning ring 202 and the ring-cutting tape when removing the ring, which is conducive to separating the thinning ring 202 and the ring-cutting tape. In addition, compared with Figure 7 (b) The pointed end and the arc-shaped protrusion can prevent, for example, the tip of the ring removal clamping jaw from piercing and breaking the ring cutting tape, resulting in uneven force on the thinned ring 202 at the ring removal clamping jaws 304, 305 and 306, causing the thinned ring 202 to break.

[0098] like Figure 7 As shown in (d), the first layer 307 of the ring removal clamp is set to a wavy or serrated bottom, which reduces the contact area between the bottom of the first layer 307 and the ring cutting tape. When removing the ring, the ring cutting tape is prevented from adhering to the bottom of the first layer 307, affecting the ring removal efficiency.

[0099] Continue to refer Figure 3 and Figure 5 The ring removal unit 303 also includes: a pressure sensing module 311, which is arranged on the ring removal clamp in a one-to-one correspondence, and is used to test the force of the ring removal clamp acting on the wafer.

[0100] The pressure sensing module 311 is disposed on the connecting member 309 between the first layer 307 and the second layer 308 , and is located at a side where the first layer 307 contacts the thinning ring 202 .

[0101] In this embodiment, the pressure sensing module 311 is disposed on the connecting piece 309 on the ring taking clamp 304, the ring taking clamp 305 and the ring taking clamp 306. The pressure sensing module on the connecting piece 309 on the ring taking clamp 306 is not shown.

[0102] The one-to-one correspondence is set on the ring removing jaws, that is, the number of pressure sensing modules 311 is equal to that of the ring removing jaws, and one pressure sensing module 311 corresponds to one ring removing jaw; the pressure sensing module 311 is used to test the force of the ring removing jaw on the wafer, that is, to test the force of the ring removing jaw on the thinning ring 202, and to determine whether the force of the ring removing jaw on the thinning ring 202 exceeds the set value according to the pressure sensing module 311; because when removing the ring, there is a possibility that the ring removing jaw squeezes the thinning ring 202, and the squeezed thinning ring 202 squeezes the thinned wafer body 201; for example, when the force of the ring removing jaw on the thinning ring 202 exceeds the set value, after the ring is removed, it is necessary to detect whether there are cracks on the edge of the thinned wafer body 201 to prevent it from flowing into the next process, thereby saving the production cycle.

[0103] The ring removal unit also includes: at least three first connecting rods, one end of each first connecting rod is movably connected to the bracket, and the other end of each first connecting rod is rotatably connected to a ring removal clamp; wherein the first connecting rods surround the bracket and are evenly distributed.

[0104] Continue to refer Figure 6 In this embodiment, the number of the first connecting rods is three, namely a first connecting rod 315, a first connecting rod 316, and a first connecting rod 317.

[0105] One end of each of the first connecting rods is movably connected to the bracket. In the present embodiment, that is, the bracket 300 is perpendicular to the surface of the wafer. Along the radial direction of the wafer, the first connecting rods 315, 316 and 317 can all be extended and contracted. When removing the ring, on the one hand, it is convenient to adjust the relative position of the ring removing claws and the wafer base, thereby reducing the risk of the ring removing unit scratching the wafer. On the other hand, it can adapt to the removal of rings of different wafer sizes.

[0106] The other end of each first connecting rod is rotatably connected to a ring removal clamp. In this embodiment, the other end of the first connecting rod 315 is rotatably connected to the ring removal clamp 304, the other end of the first connecting rod 316 is rotatably connected to the ring removal clamp 305, and the other end of the first connecting rod 317 is rotatably connected to the ring removal clamp 306.

[0107] Continue to refer Figure 5 and Figure 6 , taking the first connecting rod 315 and the ring taking jaw 304 as an example, the other end of the first connecting rod 315 is rotatably connected to the ring taking jaw 304. For other first connecting rods rotatably connected to the ring taking jaw, reference may be made to the description of the rotatable connection between the first connecting rod 315 and the ring taking jaw 304.

[0108] The first connecting rod 315 includes an area 318 and an area 319, and the area 318 and the area 319 are vertically connected. The ring removal clamp 304 rotates around the area 319 with the area 319 as an axis, and the rotation direction F can be clockwise or counterclockwise. In this embodiment, the rotation direction F is clockwise. Figure 6 The following beneficial effects are achieved: when the ring-taking jaw 304 hits the thinning ring 202, since the ring-taking jaw 304 is rotatably connected to the first connecting rod 315, compared with the fixed connection between the ring-taking jaw 304 and the first connecting rod 315, the probability of the ring-taking jaw 304 damaging and / or breaking the thinning ring 202 can be reduced, that is, the risk of the ring-taking unit scraping the wafer is reduced.

[0109] Continue to refer Figure 6 The first connecting rods are evenly distributed around the bracket, that is, the angles between the first connecting rods 315 and 316, the angles between the first connecting rods 316 and 317, and the angles between the first connecting rods 317 and 315 are equal, so that the forces exerted by the first connecting rods 315, 316, and 317 on the thinning ring 202 are uniform, thereby reducing the risk of the ring removal unit scraping the wafer.

[0110] Continue to refer Figure 6 The wafer ring removal device includes: a scanning unit 320, which is used to determine the position of the wafer base 301 for placing the wafer, and the first relative position of the thinning ring 202 relative to the center of the wafer base 301.

[0111] The scanning unit 320 is used to determine the position of the wafer base 301 for placing the wafer, that is, the scanning unit 320 determines the center of the wafer base 301. The scanning unit 320 is used to determine the first relative position of the thinning ring 202 relative to the center of the wafer base 301, that is, the scanning unit 320 uses the center of the wafer base 301 as a reference point to scan and obtain the distance between the edge position of the thinning ring 202 and the center of the wafer base 301, and this distance is the first relative position.

[0112] Continue to refer Figure 4 and Figure 6 The scanning unit includes: a second connecting rod 321, one end of which is movably connected to the bracket 300; a light sensor 322, which is connected to the other end of the second connecting rod 321 and is used to obtain the position of the thinning ring 202; wherein the light sensor 322 is coupled to the computing unit 323 to transmit the position of the thinning ring 202 obtained by the light sensor 322 to the computing unit 323.

[0113] In this embodiment, one end of the second connecting rod 321 is movably connected to the bracket 300 , that is, one end of the second connecting rod 321 is movably connected to the bracket 300 through the area 500 of the bracket 300 .

[0114] The area 503 of the bracket 300 is parallel to the wafer surface, and one end of the second connecting rod 321 is movably connected to the bracket 300 along the radial direction parallel to the wafer, that is, the second connecting rod 321 can be extended and contracted along the direction parallel to the wafer surface to adapt to wafer rings of different sizes.

[0115] In this embodiment, the optical sensor 322 is connected to the other end of the second connecting rod 321, and is used to obtain the position of the thinning ring 202, wherein the optical sensor 322 is coupled to the computing unit, that is, the scanning unit controls the optical sensor 322 to move along the edge of the thinning ring 202, and obtains the distance between the edge of the thinning ring 202 and the center of the wafer base 301, that is, the first relative position, and the optical sensor 322 is coupled to the computing unit, and is used to transmit the first relative position to the computing unit.

[0116] Continue to refer Figure 6 The wafer ring removal device includes: a calculation unit 323, which is used to calculate the second relative position of the center of the thinned wafer body 201 relative to the center of the wafer base 301 based on the first relative position and the position of the wafer base 301.

[0117] That is, the calculation unit 323 calculates the center of the wafer base 301 according to the position of the wafer base 301, and the calculation unit 323 calculates the position of the center of the thinned wafer body 201 according to the first relative position. The calculation unit 323 calculates the second relative position of the center of the thinned wafer body 201 relative to the center of the wafer base 301 according to the center of the wafer base 301 and the center of the thinned wafer body 201. The second relative position is the distance that the center of the thinned wafer body 201 deviates from the center of the wafer base 301.

[0118] Continue to refer Figure 3 , Figure 4 and Figure 6 The wafer ring removal device includes: a control unit (not shown), which adjusts the relative position of the ring removal unit 303 and the thinning ring 202 according to the second relative position, and controls the ring removal unit 303.

[0119] That is, the control unit adjusts the relative position of the ring taking unit 303 and the thinning ring 202, and adjusts the opening angle of the ring taking jaws 304, 305, and 306 in the ring taking unit according to the distance that the center of the thinned wafer body 201 deviates from the center of the wafer base 301; the control unit controls the opened ring taking jaws 304, 305, and 306 to move closer to the thinning ring 202, so that the ring taking jaws 304, 305, and 306 can move closer to the thinning ring 202. , the ring removing jaws 306 clamp the thinning ring 202, that is, the thinning ring 202 is clamped between the first layer 307 and the second layer 308 of the ring removing jaws 304, 305 and 306; along the direction perpendicular to the wafer surface, the control unit controls the ring removing jaws 304, 305 and 306 that clamp the thinning ring 202 to move away from the wafer to remove the thinning ring 202 from the wafer, so as to remove the thinning ring 202, thereby reducing the risk of the ring removing unit scratching the wafer.

[0120] It should be noted that the opening angles of the ring removing jaws 304, 305 and 306 in the ring removing unit are adjusted, that is, the ring removing jaws 304 and 305 are moved in a direction parallel to the wafer surface so that the ring removing jaws 304 and 305 do not touch the wafer to be removed.

[0121] The wafer ring removal device comprises: a rough alignment unit; the rough alignment unit comprises: a third connecting rod, one end of which is connected to the bracket; a rough alignment clamp connected to the other end of the third connecting rod, which is used to place the wafer on the wafer base and make the distance between the center of the wafer and the center of the wafer base within a preset alignment error. That is, the rough alignment unit is used to roughly align the center of the wafer with the center of the wafer base to prevent the position of the wafer on the wafer base from shifting too much, so that the thinning ring shifts to the wafer base, reducing the efficiency of the ring removal unit in removing the ring, or the ring removal unit cannot remove the ring.

[0122] Continue to refer Figure 4 The wafer ring removal device comprises: a rough alignment unit 400; the rough alignment unit 400 is movably connected to the support 300 through the area 501 of the support 300. The movably connected means that the rough alignment unit 400 can move in a direction parallel to the wafer surface and in a direction perpendicular to the wafer surface.

[0123] refer to Figure 8 and Fig. 9 , combined with Figure 4The rough alignment unit 400 includes: a third connecting rod, one end of which is connected to the bracket; the number of the third connecting rods is at least 3, and a rough alignment clamp connected to the other end of the third connecting rod, which is used to place the wafer on the wafer base and make the distance between the center of the wafer and the center of the wafer base within a preset alignment error. The number of the rough alignment clamps is at least 3, which reduces the risk of the ring removal unit scraping the wafer.

[0124] It should be noted that Fig. 9 Marks E1 and E2 in the figure are the boundaries after the thinned wafer body 201 and the thinning ring 202 are separated.

[0125] In this embodiment, the number of the third connecting rods is 3, namely, the third connecting rod 401, the third connecting rod 402, and the third connecting rod 403. The number of the coarse alignment clamps is 3, namely, the coarse alignment clamp 404, the coarse alignment clamp 405, and the coarse alignment clamp 406. One end of the third connecting rod 401 is connected to the bracket 300 via the region 501 of the bracket 300, and the other end of the third connecting rod 401 is connected to the coarse alignment clamp 404, one end of the third connecting rod 402 is connected to the bracket 300 via the region 501 of the bracket 300, and the other end of the third connecting rod 402 is connected to the coarse alignment clamp 405, one end of the third connecting rod 403 is connected to the bracket 300 via the region 501 of the bracket 300, and the other end of the third connecting rod 403 is connected to the coarse alignment clamp 406.

[0126] It should be noted that, in this embodiment, the relevant configuration of the coarse alignment jaws may refer to the ring removal jaws, which will not be described in detail here.

[0127] Continue to refer Figure 3 The wafer ring removal device includes: a cutting tape 601 for bonding wafers; a cutting tape frame 600 for removing the cutting tape 601, wherein the cutting tape frame 600 is located on the edge area of ​​the cutting tape 601; wherein the wafer after bonding is located on the central area of ​​the cutting tape 601, and there is a gap between the cutting tape frame 600 to prevent the cutting tape frame 600 from damaging the wafer during the ring removal process.

[0128] The circular cutting tape 601 includes an ultraviolet irradiation tape or a heat-sensitive tape.

[0129] The circular cutting tape 601 covers the entire surface of the wafer base 301 and extends to the carrier 302 outside the wafer base 301 .

[0130] The wafer ring removal device comprises: a motor (not shown) coupled to the rough alignment clamp and the ring removal clamp, and the control unit controls the motor to drive the rough alignment clamp and the ring removal clamp to move.

[0131] The control unit controls the motor to drive the rough alignment clamp to clamp the wafer, and drives the rough alignment clamp behind the wafer to move, so that the distance between the center of the wafer and the center of the wafer base is within a preset alignment error, so as to achieve rough alignment of the wafer and the wafer base. The control unit controls the motor to drive the ring removal clamp to clamp the thinning ring, and drives the ring removal clamp behind the wafer to move in a direction perpendicular to the wafer surface and away from the wafer, so as to remove the thinning ring.

[0132] Continue to refer Figure 8 The motor is coupled to the coarse alignment jaw 404, the coarse alignment jaw 405, and the coarse alignment jaw 406. The control unit controls the motor to drive the coarse alignment jaw 404, the coarse alignment jaw 405, and the coarse alignment jaw 406 to move, so as to achieve coarse alignment of the wafer and the wafer base.

[0133] Continue to refer Figure 6 The motor is coupled to the ring taking jaw 305, the ring taking jaw 304, and the ring taking jaw 306, and the control unit controls the motor to drive the ring taking jaw 305, the ring taking jaw 304, and the ring taking jaw 306 to move to achieve removal and thinning.

[0134] In order to solve the technical problem, accordingly, an embodiment of the present invention further provides a wafer ring removal method, which is applied to a wafer ring removal device; Fig.10 The figure is a flow chart of a wafer ring removal method according to an embodiment of the present invention.

[0135] refer to Figures 3 to 9 The wafer includes: a thinned wafer body 201 and a thinning ring 202 surrounding the thinned wafer body 201; the wafer ring removal device includes: a ring removal unit 303, a scanning unit 320, a calculation unit 323, and a control unit.

[0136] The wafer ring removal device further includes: a rough alignment unit 400, a ring-cutting tape 601, and a ring-cutting tape frame 600. The rough alignment unit 400 includes: a rough alignment clamp.

[0137] The wafer ring removal device also includes: a motor, a light sensor 322, and a ring removal clamp.

[0138] In this embodiment, the number of the ring removal jaws is 3, namely, the ring removal jaw 304, the ring removal jaw 305, and the ring removal jaw 306. Figure 6As shown; the number of the coarse alignment jaws is 3, namely, coarse alignment jaw 404, coarse alignment jaw 405, coarse alignment jaw 406, as Figure 8 shown.

[0139] In this embodiment, for specific descriptions of the ring removal unit 303, scanning unit 320, calculation unit 323, control unit, coarse alignment unit 400, coarse alignment clamp, circular cutting tape 601, circular cutting tape frame 600, motor, light sensor 322, ring removal clamp, etc., please refer to the description in the wafer ring removal device of the previous embodiment and will not be elaborated here.

[0140] The ring removal method comprises: the ring removal method comprises: adsorbing a wafer with a ring cutting tape bonded thereto onto a wafer base; using the scanning unit to determine the position of the wafer base for placing the wafer, and the first relative position of the thinning ring relative to the center of the wafer base; using the calculation unit to calculate the second relative position of the center of the thinned wafer body relative to the center of the wafer base according to the first relative position and the position of the wafer base; using the control unit to adjust the relative position of the ring removal unit and the thinning ring according to the second relative position, control the ring removal unit to separate the thinned wafer body and the thinning ring, and remove the thinning ring.

[0141] Before the step of placing the wafer with the ring cutting tape on the wafer base, the ring removal method also includes: using the control unit to adjust the position of the wafer and the wafer base through the coarse alignment clamps of the coarse alignment unit so that the distance between the center of the wafer and the center of the wafer base is within a preset alignment error.

[0142] refer to Fig.10 and Fig.11 , combined with Figures 3 to 9 ;in Fig.11 Schematic diagram of the positional relationship between the center of a wafer and the center of a wafer substrate according to an embodiment of the present invention. The process of the wafer ring removal method mainly includes the following steps:

[0143] Step S11: using the control unit to adjust the positions of the wafer and the wafer base through the coarse alignment jaws of the coarse alignment unit so that the distance between the center of the wafer and the center of the wafer base is within a preset alignment error.

[0144] refer to Figure 8 , Fig. 9In this embodiment, the control unit controls the motor to drive the coarse alignment jaws 404, coarse alignment jaws 405, and coarse alignment jaws 406 to clamp the wafer together, and drives the coarse alignment jaws 404, coarse alignment jaws 405, and coarse alignment jaws 406 after clamping the wafer to move in a direction parallel and / or perpendicular to the surface of the wafer to adjust the position of the wafer and the wafer base 301, so that the distance between the center of the wafer (i.e., the center of the wafer) and the center of the wafer base 301 is within a preset alignment error, so as to achieve coarse alignment of the wafer and the wafer base 301, prevent the alignment error between the wafer and the wafer base 301 from being too large, resulting in the subsequent inability to remove the ring or difficulty in removing the ring, and increase the risk of the ring removal jaws 304, 305, and 306 hitting the thinned wafer body 201 and / or the thinning ring 202 to cause the wafer to be scratched or broken, that is, reduce the risk of the ring removal unit scratching the wafer.

[0145] Typically, a first alignment mark (not shown) is designed on the wafer base 301, and a second alignment mark (not shown) is designed on the wafer. By fitting the first alignment mark and the second alignment mark, the wafer and the wafer base 301 are aligned.

[0146] Step S12: adsorbing the wafer with the dicing tape on the wafer base.

[0147] continue Figure 8 , Fig. 9 In this embodiment, after the first alignment mark and the second alignment mark are overlapped, the control unit controls the motor to drive the coarse alignment jaws 404, 405, and 406 that clamp the wafer to move in a direction perpendicular to the surface of the wafer, and place the wafer with the dicing tape on the wafer base so that the dicing tape contacts the wafer base and the carrier. The adsorption holes (not shown) of the wafer base adsorb the wafer with the dicing tape on the wafer base, and at the same time, the adsorption holes located on the carrier adsorb the dicing tape located outside the wafer base on the carrier.

[0148] Step S13: Using the scanning unit, determine the position of the wafer base for placing the wafer, and the first relative position of the thinning ring relative to the center of the wafer base, and using the calculation unit, calculate the second relative position of the center of the thinned wafer body relative to the center of the wafer base based on the first relative position and the position of the wafer base.

[0149] In this embodiment, the following sequence is followed: determining the center of the wafer base 301 , calculating the center of the thinned wafer body 201 according to the first relative position, and determining the second relative position according to the center of the wafer base 301 and the center of the thinned wafer body 201 .

[0150] The center of the wafer pedestal 301 is determined as follows:

[0151] refer to Fig.11 , combined with Figure 3 The scanning unit controls the optical sensor 322 to move along the edge 800 of the wafer base 301 to obtain the position of the edge 800 of the wafer base 301 and provide data for calculating the center of the wafer base.

[0152] Continue to refer Fig.11 , combined with Figure 3 In this embodiment, in order to improve production efficiency, along the edge 800 of the wafer base 301, the scanning unit uniformly scans three points on the edge 800 of the wafer base 301, such as point A (X1, Y1), point B (X2, Y2), and point C (X3, Y3). The calculation unit calculates the center M1 of the wafer base 301 according to the positions of the three points on the edge 800 of the wafer base 301 obtained by the scanning unit, that is, the position of the wafer base 301 for placing the wafer is determined by the scanning unit. In other embodiments, more than three points can be selected. The more points are selected for scanning, the more accurate the center M1 of the wafer base 301 obtained by the calculation unit, and the lower the risk of the ring removal unit scraping the wafer.

[0153] The center of the thinned wafer body 201 is calculated according to the first relative position, and the process is as follows:

[0154] Taking the center M1 of the wafer base 301 as a reference point, the scanning unit controls the optical sensor 322 to move along the edge 801 of the wafer to obtain the position of the edge 801 of the wafer, that is, to obtain the first relative position of the thinning ring 202 relative to the center M1 of the wafer base 301, thereby providing data for calculating the center of the thinned wafer body 201.

[0155] Continue to refer Fig.11 , combined with Figure 3 In this embodiment, in order to improve production efficiency, along the edge of the wafer, the scanning unit uniformly scans three points on the edge 801 of the wafer, such as point D (X4, Y4), point E (X5, Y5), and point F (X6, Y6), that is, obtains the first relative position of the thinning ring 202 relative to the center M1 of the wafer base 301. The calculation unit calculates the center M2 of the thinned wafer body 201 according to the first relative position, that is, according to the three points on the wafer edge 801 obtained by the scanning unit. In other embodiments, more than three points can be selected. The more points are selected for scanning, the more accurate the center M2 of the thinned wafer body 201 obtained by the calculation unit, and the lower the risk of the ring removal unit scratching the wafer.

[0156] The second relative position is determined according to the center of the circular base 301 and the center of the thinned wafer body 201, and the process is as follows:

[0157] The calculation unit calculates the distance between the center M1 and the center M2 according to the center M1 of the wafer base 301 (i.e., the position of the wafer base 301) and the center M2 of the thinned wafer body 201, and obtains the second relative position of the center M2 of the thinned wafer body 201 relative to the center M1 of the wafer base 301, that is, calculates the distance that the thinned wafer body 201 deviates from the wafer base 301.

[0158] Step S14: using the control unit to adjust the relative position between the ring removing unit and the thinning ring according to the second relative position, controlling the ring removing unit to separate the thinned wafer body and the thinning ring, and removing the thinning ring.

[0159] Continue to refer Fig.11 , combined with Figure 3 and Figure 6 In this embodiment, the control unit controls the motor to drive the ring removal unit 303 to move relative to the wafer along a direction perpendicular to and / or parallel to the wafer surface based on the second relative position of the center M2 of the thinned wafer body 201 relative to the center M1 of the wafer base 301, so as to adjust the relative positions of the ring removal jaws 304, 305, and 306 of the ring removal unit 303 and the thinning ring 202.

[0160] The control unit adjusts the opening angles of the ring removing jaws 304 , 305 , 306 according to the relative positions of the ring removing jaws 304 , 305 , 306 and the thinning ring 202 , so that the ring removing jaws 304 , 305 , 306 can clamp the wafer.

[0161] The control unit controls the motor to drive the ring removal jaws 304, 305, and 306 that clamp the wafer to move in a direction perpendicular to and away from the wafer surface to remove the thinning ring 202 from the wafer, that is, to control the ring removal unit 303 to separate the thinned wafer body 201 and the thinning ring 202 to remove the thinning ring 202.

[0162] refer to Fig.12 , is a schematic diagram of the separation of the thinned wafer body and the thinning ring after the ring is removed by the wafer ring removal device according to an embodiment of the present invention, that is, a schematic diagram of the separation of the thinned wafer body 201 and the thinning ring 202.

[0163] It should be noted that the reference Fig.11When the distance between the ring removal jaws 305 and the wafer base 301 is less than or equal to the second relative position d1, the ring removal is stopped to reduce the risk of the ring removal jaws 305 hitting the thinning ring 202. Then, the wafer needs to be removed from the wafer base 301, and then steps S11 to S14 are repeated. The distance between the ring removal jaws 305 and the wafer base 301 is the distance between the ring removal jaws 305 and the wafer base 301 when the ring removal jaws 305 are opened at the maximum angle.

[0164] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A wafer ring removal device, characterized in that: The ring removing device performs a ring removing operation on the wafer; The wafer comprises: a thinned wafer body and a thinning ring surrounding the thinned wafer body; the ring removal device comprises: A ring removing unit, used for separating the thinned wafer body and the thinning ring, and removing the thinning ring; a scanning unit, configured to determine a position of a wafer base for placing the wafer, and a first relative position of the thinning ring relative to a center of the wafer base; a calculation unit, configured to calculate a second relative position of the center of the thinned wafer body relative to the center of the wafer base according to the first relative position and the position of the wafer base; The control unit adjusts the relative position between the ring removing unit and the thinning ring according to the second relative position, and controls the ring removing unit.

2. The ring removal device according to claim 1, characterized in that: Also includes: A support, movable relative to the wafer base; The ring removal unit comprises: A ring-taking gripper capable of grasping the thinned ring; At least three first connecting rods, one end of each first connecting rod is movably connected to the bracket, and the other end of each first connecting rod is rotatably connected to a ring removal clamp; Wherein, the first connecting rods surround the bracket and are evenly distributed.

3. The ring removal device according to claim 2, characterized in that: The scanning unit comprises: a second connecting rod, one end of which is movably connected to the bracket; an optical sensor connected to the other end of the second connecting rod and used to obtain the position of the thinning ring; Wherein, the light sensor is coupled to the computing unit.

4. The ring removal device according to claim 2, characterized in that: Also includes: Coarse alignment unit; The coarse alignment unit comprises: a third connecting rod, one end of which is connected to the bracket; A coarse alignment clamp is connected to the other end of the third connecting rod and is used to place the wafer on the wafer base so that the distance between the center of the wafer and the center of the wafer base is within a preset alignment error.

5. The ring removal device according to claim 2, characterized in that: The cross-sectional shape of the ring-removing clamp on a plane perpendicular to the wafer base is in the shape of an "I".

6. The ring removal device according to claim 5, characterized in that: Also includes: The contact end between the ring-removing clamp and the thinned ring includes one or more of a square cylinder, a round cylinder, an elliptical cylinder, and a cone.

7. The ring removal device according to claim 1, characterized in that: Also includes: Circular cutting tape, used to stick crystal circles; A ring-cut tape frame for removing the ring-cut tape, the ring-cut tape frame being located on an edge region of the ring-cut tape; The bonded wafer is located on the central area of ​​the circular cutting tape and is spaced apart from the circular cutting tape frame.

8. The ring removal device according to claim 2, characterized in that: The ring removal unit further includes: a pressure sensing module, which is arranged on the ring removal clamps in a one-to-one correspondence and is used to test the force of the ring removal clamps acting on the wafer.

9. The ring removal device according to claim 4, characterized in that: Also includes: The motor is coupled to the rough alignment clamp and the ring taking clamp. The control unit controls the motor to drive the rough alignment clamp and the ring taking clamp to move.

10. A wafer ring removal method, applied to a wafer ring removal device, characterized in that: The wafer comprises: a thinned wafer body and a thinning ring surrounding the thinned wafer body; The wafer ring removal device comprises: Ring taking unit, scanning unit, calculation unit, control unit; The ring removal method comprises: Adsorbing the wafer with the dicing tape bonded thereto onto a wafer base; Using the scanning unit, determining the position of a wafer base for placing the wafer and a first relative position of the thinning ring relative to the center of the wafer base; Using the calculation unit, according to the first relative position and the position of the wafer base, calculate the second relative position of the center of the thinned wafer body relative to the center of the wafer base; The control unit is used to adjust the relative position of the ring removing unit and the thinning ring according to the second relative position, and control the ring removing unit to separate the thinned wafer body and the thinning ring, and remove the thinning ring.

11. The method for removing the ring according to claim 10, characterized in that: The wafer ring removal device further includes: a rough alignment unit; The coarse alignment unit comprises: a coarse alignment clamping jaw; Before the step of placing the wafer with the ring cutting tape bonded thereto on the wafer base, the ring removal method further comprises: The control unit is used to adjust the positions of the wafer and the wafer base through the coarse alignment clamps of the coarse alignment unit, so that the distance between the center of the wafer and the center of the wafer base is within a preset alignment error.

Images