Wafer edge trimmer and knife board replacement method thereof

Abstract

The invention provides a wafer edge trimmer and a method for replacing a sharpening board of the wafer edge trimmer. According to the wafer edge trimmer, a knife sharpening plate supply clamping groove for placing a new knife sharpening plate, a knife sharpening plate collection clamping groove for placing an old knife sharpening plate and an adsorption shaft which is installed on a knife shaft and can move up and down are additionally arranged in the wafer edge trimmer, and when the knife sharpening plate needs to be replaced, the knife shaft and the adsorption shaft transfer the knife sharpening plate to be replaced in a machine table to the knife sharpening plate collection clamping groove; and then the new sharpening board in the sharpening board supply clamping groove is transferred to the sharpening board carrying table of the machine table, so that the sharpening board can be automatically replaced without opening a cavity in the operation process, the efficiency of the machine table is improved, the manual operation is reduced, and the influence on a wafer is reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and particularly relates to a wafer trimming machine and a method for replacing a grinding plate thereof. Background Art

[0002] With the continuous progress of chip manufacturing technology and imaging dedicated technology, the front-illuminated image sensor (FSI) has its physical limitations. A major problem with FSI is that light needs to pass through a relatively thick metal wiring layer before entering silicon, which results in more photon losses and affects the final quantum efficiency (QE). Especially as the pixel size continues to shrink, the effective photosensitive area as a proportion of the entire pixel region becomes more limited. To solve this problem, currently, image sensors using the back-illuminated (BSI) technology are adopted. The BSI process includes the following steps: (Flip and Bond) > (Back thinning process) > (DTI process) > (HK film process) > (Metal Grid process) > (Open PAD process).

[0003] Since the edge of the wafer is arc-shaped, when back thinning is performed after wafer flip bonding, various shapes are formed in the edge grinding step. Therefore, it is necessary to add a wafer trimming process before wafer flip bonding to cut the edge of the wafer to minimize edge cracking and peeling. Subsequently, during the CMP process, a polishing process is carried out, and the edge of the wafer is rounded. It can be seen that the wafer trimming process is particularly important in the BSI process.

[0004] The wafer trimming process is generally completed by a wafer trimming machine, which mainly includes alternately performing blade grinding operations and wafer trimming operations. In the prior art, a single grinding plate is installed on the grinding plate carrier, and according to the different trimming processes, it is polished and repaired according to the surface flatness of the cutting tool. When the grinding plate is used, one cycle is a 360° rotation from the origin, and then a new grinding plate needs to be replaced. Therefore, when replacing the grinding plate during the operation process, generally, after all the wafer processes in the machine are completed, the cavity is opened for replacement.

[0005] However, opening the cavity during the operation process will allow other substances such as particulate matter from the outside to enter the interior of the machine, which is extremely likely to affect the circuit effectiveness on the wafer surface and increase the instability factors of the machine operation. Summary of the Invention

[0006] The purpose of the present invention is to provide a wafer trimming machine and a method for replacing a grinding plate, which can achieve automatic replacement of the grinding plate without opening the cavity during the operation process, improve the machine efficiency, and reduce the impact on the wafer.

[0007] To achieve the above purposes, the present invention is realized through the following technical solutions:

[0008] A wafer trimming machine includes: a wafer stage for carrying a wafer to be processed, a grinding plate stage located on the side of the wafer stage, and a tool shaft equipped with a cutting tool. The tool shaft can move in the XY plane to bring the cutting tool close to the wafer stage for wafer trimming and close to the grinding plate stage for grinding and repairing the cutting tool. It further includes:

[0009] An adsorption shaft, vertically installed on the tool shaft, with a vacuum chuck at its bottom;

[0010] A driving device, installed on the tool shaft and connected to the adsorption shaft, for driving the adsorption shaft to move in the Z direction;

[0011] A grinding plate supply card slot for placing unused grinding plates;

[0012] A grinding plate collection card slot for placing used grinding plates;

[0013] When a grinding plate needs to be replaced, the tool shaft moves above the grinding plate stage, and the driving device drives the adsorption shaft to descend so that the vacuum chuck sucks the used grinding plate in the grinding plate stage; the tool shaft moves above the grinding plate collection card slot, and the driving device drives the adsorption shaft to descend so that the vacuum chuck places the used grinding plate into the grinding plate collection card slot; the tool shaft moves above the grinding plate supply card slot, and the driving device drives the adsorption shaft to descend so that the vacuum chuck sucks an unused grinding plate from the grinding plate supply card slot; the tool shaft moves above the grinding plate stage, and the driving device drives the adsorption shaft to descend so that the vacuum chuck places the unused grinding plate onto the grinding plate stage.

[0014] Optionally, the driving device is a cylinder.

[0015] Optionally, three limit sensors are provided on the tool shaft along the lifting path of the adsorption shaft, and the three limit sensors are respectively used to define the initial position of the adsorption shaft, the position for sucking the grinding plate, and the position for rising after sucking the grinding plate.

[0016] Optionally, the driving device is a motor.

[0017] Optionally, a limit sensor is provided on the tool shaft along the lifting path of the adsorption shaft to define the initial position of the adsorption shaft, and the driver of the motor records the position of the adsorption shaft during the lifting and lowering process of the adsorption shaft.

[0018] Optionally, an installation hole is provided on the tool shaft in the vertical direction, the adsorption shaft passes through the installation hole, and the driving device is installed in the installation hole.

[0019] Optionally, when the adsorption shaft rises to the initial position, the vacuum chuck at its bottom is located inside the tool shaft.

[0020] Optionally, the tool shaft is provided with a door plate covering the bottom of the mounting hole. When the sharpening plate needs to be replaced, the door plate is opened, and when the adsorption shaft returns to the initial position after the sharpening plate replacement is completed, the door plate is closed.

[0021] A method for replacing a sharpening plate, characterized in that it is implemented by using the wafer trimming machine described in any one of the above, and includes the following steps:

[0022] Step S1, the tool shaft moves above the sharpening plate carrier, and the driving device drives the adsorption shaft to descend so that the vacuum chuck sucks the used sharpening plate in the sharpening plate carrier.

[0023] Step S2, the tool shaft moves above the sharpening plate collection slot, and the driving device drives the adsorption shaft to descend so that the vacuum chuck places the used sharpening plate into the sharpening plate collection slot.

[0024] Step S3, the tool shaft moves above the sharpening plate supply slot, and the driving device drives the adsorption shaft to descend so that the vacuum chuck sucks the unused sharpening plate from the sharpening plate supply slot.

[0025] Step S4, the tool shaft moves above the sharpening plate carrier, and the driving device drives the adsorption shaft to descend so that the vacuum chuck places the unused sharpening plate onto the sharpening plate carrier.

[0026] Optionally, before the tool shaft moves above the sharpening plate collection slot in step S2, before the tool shaft moves above the sharpening plate supply slot in step S3, and before the tool shaft moves above the sharpening plate supply slot in step S4, it further includes: the driving device drives the adsorption shaft to rise a certain distance.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] By adding a sharpening plate supply slot for placing new sharpening plates, a sharpening plate collection slot for placing used sharpening plates, and a vertically movable adsorption shaft mounted on the tool shaft in the wafer trimming machine, when the sharpening plate needs to be replaced, the tool shaft and the adsorption shaft transfer the sharpening plate to be replaced in the machine to the sharpening plate collection slot, and then transfer the new sharpening plate in the sharpening plate supply slot to the sharpening plate carrier in the machine, thereby realizing automatic replacement of the sharpening plate without opening the cavity during the operation process, improving the machine efficiency, reducing manual operation, and reducing the impact on the wafer. Description of the Drawings

[0029] To more clearly illustrate the technical solution of the present invention, the following will briefly introduce the accompanying drawings required in the description. Obviously, the accompanying drawings in the following description are an embodiment of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings:

[0030] Figure 1 The top view of the wafer trimming machine provided by an embodiment of the present invention;

[0031] Figure 2 The front view of the wafer trimming machine provided by an embodiment of the present invention;

[0032] Figure 3 The front view of the wafer trimming machine provided by another embodiment of the present invention;

[0033] Figure 4 The flowchart of the method for replacing the grinding plate provided by an embodiment of the present invention. Detailed implementation manners

[0034] The following further details the solution proposed by the present invention in conjunction with the accompanying drawings and specific implementation manners. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are in a very simplified form and use non-precise scales, only for the purpose of facilitating and clearly assisting in explaining the embodiments of the present invention. In order to make the purpose, features, and advantages of the present invention more obvious and understandable, please refer to the accompanying drawings. It should be noted that the structures, scales, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology 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 substance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the efficacy that the present invention can produce and the purpose that can be achieved, should still fall within the scope covered by the technical content disclosed by the present invention.

[0035] The core idea of the present invention is to add a grinding plate supply slot for placing a new grinding plate, a grinding plate collection slot for placing an old grinding plate, and a vertically movable adsorption shaft installed on the tool shaft in the wafer trimming machine. When replacing the grinding plate is required, the tool shaft and the adsorption shaft transfer the grinding plate to be replaced in the machine to the grinding plate collection slot, and then transfer the new grinding plate in the grinding plate supply slot to the grinding plate carrier in the machine, thereby realizing automatic replacement of the grinding plate without opening the cavity during the operation process, improving the efficiency of the machine, reducing manual operation, and reducing the impact on the wafer.

[0036] Such as Figure 1As shown in the figure, the wafer trimming machine provided by the present invention includes: a wafer stage 10 for carrying the wafer W to be processed, a grinding plate stage 20 located on the side of the wafer stage 10, and a tool shaft 30 equipped with a cutting tool 31. The wafer stage 10 and the grinding plate stage 20 are both located in the XY plane. The tool shaft 30 can move in the XY plane so that the cutting tool 31 approaches the wafer stage 10 to trim the wafer W and approaches the grinding plate stage 20 to grind and repair the cutting tool 31. The wafer stage 10 can rotate to drive the wafer W to be processed to rotate. When the machine is initialized, the tool shaft 30 is located at the starting position, and then moves from the starting position to approach the wafer stage 10. The cutting tool contacts the edge of the wafer W to trim the edge of the wafer W. After the cutting tool 31 is used for a certain period of time, the grinding wheel blade will gradually wear and become dull, resulting in a decline in cutting quality and a reduction in the yield of finished products. Therefore, it is necessary to use a grinding plate to grind and repair the cutting tool 31. At this time, the tool shaft 30 moves in the XY plane to the grinding plate stage 20, and the cutting tool 31 contacts the grinding plate to achieve grinding and repair. After the grinding and repair is completed, the grinding plate stage 20 rotates a certain angle so that the unused area of the grinding plate can be used for grinding when the cutting tool 31 is ground next time. When the grinding plate stage 20 rotates one week, it means that all areas of the grinding plate have been used, and at this time, the grinding plate needs to be replaced.

[0037] To facilitate the automatic replacement of the grinding plate, the wafer trimming machine further includes: a suction shaft 40, vertically installed on the tool shaft 30, with a vacuum chuck at its bottom; a driving device 50, installed on the tool shaft 30 and connected to the suction shaft 40, for driving the suction shaft 40 to move in the Z direction; a grinding plate supply slot 60 for placing unused grinding plates; and a grinding plate collection slot 70 for placing used grinding plates.

[0038] Thus, when the grinding plate needs to be replaced, the tool shaft 30 moves above the grinding plate stage 20, and the driving device 50 drives the suction shaft 40 to descend so that the vacuum chuck sucks the used grinding plate in the grinding plate stage 20; the tool shaft 30 moves above the grinding plate collection slot 50, and the driving device 50 drives the suction shaft 40 to descend so that the vacuum chuck places the used grinding plate into the grinding plate collection slot 60; the tool shaft 30 moves above the grinding plate supply slot 70, and the driving device 50 drives the suction shaft 40 to descend so that the vacuum chuck sucks an unused grinding plate from the grinding plate supply slot 70; the tool shaft 30 moves above the grinding plate stage 20, and the driving device 50 drives the suction shaft 40 to descend so that the vacuum chuck places the unused grinding plate onto the grinding plate stage 20.

[0039] The knife shaft 30 can be moved in the X direction by an X-axis motion assembly and in the Y direction by a Y-axis motion assembly. The X-axis and Y-axis motion assemblies can be screw guide rail devices commonly used in the art. The screw guide rail device includes a screw, a slide rail, a slide table and a screw motor. The slide rail is arranged parallel to the X / Y axis, the screw is parallel to the slide rail, the slide table is arranged on the slide rail and cooperates with the screw thread, and the screw motor is arranged next to the slide rail to drive the screw to rotate. Optionally, the knife shaft 30 can be arranged on the slide table of the X-axis motion assembly, and the X-axis motion assembly can be arranged on the slide table of the Y-axis motion assembly, so as to realize the movement of the knife shaft 30 in the XY plane.

[0040] The driving device 50 of the adsorption shaft 40 can be a motor, and the top end of the adsorption shaft 40 is connected to the output end of the motor, and the adsorption shaft 40 is driven to rise and fall by the motor. Figure 2 As shown, a limit sensor 80 is installed on the blade shaft 30 along the lifting path of the suction shaft 40. This sensor is used to define the initial position of the suction shaft 40. During the lifting and lowering process of the suction shaft 40, the motor driver records the position of the suction shaft 40. When the machine is initialized, the suction shaft 40 is at the initial position, triggering the limit sensor 80. This position is the zero point. As the motor drives the suction shaft 40, the motor driver records the position of the suction shaft 40 in real time. The motor driver records the moving position of the suction shaft 40 to ensure the accuracy of the suction shaft 40's movement.

[0041] The driving device 50 of the adsorption shaft 40 can also be a cylinder, and the top end of the adsorption shaft 40 is connected to the output end of the cylinder, and the reciprocating motion of the cylinder drives the adsorption shaft 40 to rise and fall. Figure 3 As shown, in order to improve the displacement accuracy of the adsorption shaft 40, three limit sensors 80 are provided on the knife shaft 30 along the lifting path of the adsorption shaft 40. The three limit sensors 80 are respectively used to limit the initial position of the adsorption shaft 40, the position of the knife grinding plate, and the rising position after the adsorption shaft 40 is attracted to the knife grinding plate. When the limit sensor 81 is triggered and the limit sensors 82 and 83 are not triggered, the adsorption shaft 40 is in the initial position. When the limit sensor 82 is triggered and the limit sensors 81 and 83 are not triggered, the adsorption shaft 40 is attracted to the knife grinding plate, and the knife shaft 30 begins to move in the XY plane. When the limit sensor 83 is triggered and the limit sensors 81 and 82 are not triggered, it indicates that the adsorption shaft 40 descends to the position of the knife grinding plate. The accuracy of the lifting and lowering of the adsorption shaft 40 is determined by these three limit sensors 80.

[0042] In this embodiment, Figure 1As shown, the tool shaft 30 is provided with a mounting hole in the vertical direction, the adsorption shaft 40 is inserted into the mounting hole, and the driving device 50 is installed in the mounting hole. In other embodiments, brackets may also be added to the tool shaft 30, and the adsorption shaft 40 and the driving device 50 are installed on the brackets.

[0043] Further, when the adsorption shaft 40 rises to the initial position, the vacuum chuck at its bottom is located inside the tool shaft 30. Thus, the adsorption shaft 40 is hidden inside the tool shaft 30, and only when the grinding plate needs to be automatically replaced, the adsorption shaft 40 extends out of the tool shaft 30 to suck the grinding plate.

[0044] Further, as Figure 2 , Figure 3 shown, the tool shaft 30 is provided with a door plate 90 covering the bottom of the mounting hole. When the grinding plate needs to be replaced, the door plate 90 is opened, and when the adsorption shaft 40 returns to the initial position after the grinding plate is replaced, the door plate 90 is closed. The door plate 90 is used to prevent water stains during the wafer trimming process from splashing into the mounting hole and polluting the adsorption shaft 40.

[0045] Based on the same inventive concept, the present invention also provides a method for replacing the grinding plate, which is implemented by using the wafer trimming machine as described above. As Figure 4 shown, it includes the following steps:

[0046] Step S1, the tool shaft moves above the grinding plate carrier, and the driving device drives the adsorption shaft to descend so that the vacuum chuck sucks the used grinding plate in the grinding plate carrier;

[0047] Step S2, the tool shaft moves above the grinding plate collection slot, and the driving device drives the adsorption shaft to descend so that the vacuum chuck places the used grinding plate into the grinding plate collection slot;

[0048] Step S3, the tool shaft moves above the grinding plate supply slot, and the driving device drives the adsorption shaft to descend so that the vacuum chuck sucks the unused grinding plate from the grinding plate supply slot;

[0049] Step S4, the tool shaft moves above the grinding plate carrier, and the driving device drives the adsorption shaft to descend so that the vacuum chuck places the unused grinding plate onto the grinding plate carrier.

[0050] In addition, before the tool shaft moves above the grinding plate collection card slot in step S2, before the tool shaft moves above the grinding plate supply card slot in step S3, and before the tool shaft moves above the grinding plate supply card slot in step S4, it further includes: the driving device drives the adsorption shaft to rise a certain distance. Specifically, the adsorption shaft rises to the position of the limit sensor 2.

[0051] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the element.

[0052] Although the content of the present invention has been introduced in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. After those skilled in the art have read the above content, various modifications and alternatives to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A wafer trimming machine, comprising: A wafer stage for carrying a wafer to be processed, a sharpening plate stage located on the side of the wafer stage, and a tool shaft equipped with a cutting tool. The tool shaft can move in the XY plane to make the cutting tool approach the wafer stage to trim the wafer and approach the sharpening plate stage to grind and repair the cutting tool. It is characterized in that it further includes: A suction shaft vertically installed on the tool shaft, with a vacuum chuck at its bottom; A driving device installed on the tool shaft, connected to the suction shaft, and used to drive the suction shaft to move in the Z direction; A sharpening plate supply slot for placing unused sharpening plates; A sharpening plate collection slot for placing used sharpening plates; When a sharpening plate needs to be replaced, the tool shaft moves above the sharpening plate stage, and the driving device drives the suction shaft to descend so that the vacuum chuck sucks the used sharpening plate in the sharpening plate stage; the tool shaft moves above the sharpening plate collection slot, and the driving device drives the suction shaft to descend so that the vacuum chuck places the used sharpening plate into the sharpening plate collection slot; the tool shaft moves above the sharpening plate supply slot, and the driving device drives the suction shaft to descend so that the vacuum chuck sucks an unused sharpening plate from the sharpening plate supply slot; the tool shaft moves above the sharpening plate stage, and the driving device drives the suction shaft to descend so that the vacuum chuck places the unused sharpening plate onto the sharpening plate stage.

2. The wafer edge trimming machine according to claim 1, wherein The driving device is a cylinder.

3. The wafer trimming machine according to claim 2, wherein There are three limit sensors on the tool shaft along the lifting path of the suction shaft, and the three limit sensors are respectively used to define the initial position of the suction shaft, the position for sucking the sharpening plate, and the position for rising after sucking the sharpening plate.

4. The wafer edge trimming machine according to claim 1, characterized in that, The driving device is a motor.

5. The wafer edge trimming machine according to claim 4, wherein There is one limit sensor on the tool shaft along the lifting path of the suction shaft, which is used to define the initial position of the suction shaft. During the lifting and lowering process of the suction shaft, the driver of the motor records the position of the suction shaft.

6. The wafer edge trimming machine according to claim 1, characterized in that, The tool shaft is provided with a mounting hole along the vertical direction, the suction shaft passes through the mounting hole, and the driving device is installed in the mounting hole.

7. The wafer edge trimming machine according to claim 6, wherein, When the suction shaft rises to the initial position, the vacuum chuck at its bottom is located inside the tool shaft.

8. The wafer edge trimming machine according to claim 7, wherein, The tool shaft is provided with a door plate covering the bottom of the mounting hole. The door plate opens when a sharpening plate needs to be replaced and closes when the suction shaft returns to the initial position after the sharpening plate replacement is completed.

9. A method for replacing a sharpening board, characterized in that, Implemented by using the wafer trimming machine according to any one of claims 1 to 8, including the following steps: Step S1, the tool shaft moves above the sharpening plate stage, and the driving device drives the suction shaft to descend so that the vacuum chuck sucks the used sharpening plate in the sharpening plate stage; Step S2, the tool shaft moves above the sharpening plate collection slot, and the driving device drives the suction shaft to descend so that the vacuum chuck places the used sharpening plate into the sharpening plate collection slot; Step S3: The tool shaft moves above the grinding plate supply slot, and the driving device drives the suction shaft to descend until the vacuum suction cup sucks the unused grinding plate from the grinding plate supply slot. Step S4: The tool shaft moves above the grinding plate carrier, and the driving device drives the suction shaft to descend until the vacuum suction cup places the unused grinding plate onto the grinding plate carrier.

10. The method for replacing the sharpening board according to claim 9, characterized in that, Before the tool shaft moves above the grinding plate collection slot in step S2, before the tool shaft moves above the grinding plate supply slot in step S3, and before the tool shaft moves above the grinding plate supply slot in step S4, it further includes: the driving device drives the suction shaft to rise by a certain distance.

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