Wafer edge modification method and system

Abstract

The application discloses a wafer edge modification method and system, and is applied to the technical field of wafer preparation, and comprises the following steps: driving a to-be-modified wafer and a plurality of grinding wheels to rotate in the circumferential direction of the to-be-modified wafer; when the initial position of the edge of the to-be-modified wafer is moved to the position below the corresponding grinding wheel for the first time, the to-be-modified wafer is ground by the grinding wheel from the initial position within the stepping range corresponding to the grinding wheel, so that the edge of the to-be-modified wafer is simultaneously modified by the plurality of grinding wheels within the corresponding stepping ranges after the to-be-modified wafer rotates through the position corresponding to the last grinding wheel; and the total stepping range formed by the stepping ranges of the plurality of grinding wheels corresponds to the modification range of the edge of the to-be-modified wafer. Since the total stepping range formed by the stepping ranges of the plurality of grinding wheels corresponds to the modification range of the edge of the to-be-modified wafer, each grinding wheel only grinds within the stepping range of the grinding wheel, and the grinding position does not need to be adjusted by stepping, so that the processing time is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of wafer fabrication technology, and in particular to a wafer edge modification method and a wafer edge modification system. Background Technology

[0002] In semiconductor chip manufacturing processes, edge trimming is used, which involves thinning a certain area of ​​the wafer edge to a certain depth. For example, edge trimming is performed on the edge of one wafer before bonding to prevent edge cracking during the subsequent backside silicon removal process.

[0003] The current edge finishing process mainly involves grinding the wafer edge using a grinding wheel (also known as a dicing blade). The grinding wheel gradually moves outward from the radius to be processed until it reaches the wafer edge. The depth to which the grinding wheel sinks is the depth of the wafer edge finishing.

[0004] However, in existing technologies, processing wafer edges using grinding wheels requires multiple repetitions; for example, edge finishing with a depth of 100µm and a width of 2.5mm currently requires approximately four steps. This makes the entire edge finishing process time-consuming and costly. Therefore, providing a wafer edge finishing method that is less time-consuming is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a wafer edge finishing method with a shorter processing time; another purpose of this invention is to provide a wafer edge finishing system with a shorter processing time.

[0006] To solve the above-mentioned technical problems, the present invention provides a wafer edge modification method, comprising:

[0007] The wafer to be modified is driven to rotate relative to multiple grinding wheels along the circumferential direction of the wafer to be modified;

[0008] When the initial position of the edge of the wafer to be modified moves to the position below the corresponding grinding wheel for the first time, the grinding wheel grinds the wafer from the initial position within the step range corresponding to the grinding wheel. After rotating past the position corresponding to the last grinding wheel at the initial position, the edge of the wafer to be modified is simultaneously modified by multiple grinding wheels within the corresponding step range. The total step range formed by the step ranges of the multiple grinding wheels corresponds to the modification range of the edge of the wafer to be modified.

[0009] Optionally, it includes four grinding wheels arranged circumferentially around the wafer to be modified.

[0010] Optionally, the four grinding wheels are evenly spaced along the circumference of the wafer to be modified.

[0011] Optionally, any two of the multiple step ranges may not completely overlap.

[0012] Optionally, after simultaneously polishing the edges of the wafer to be polished using multiple polishing wheels within corresponding step ranges, the method further includes:

[0013] After the grinding termination condition is met at the initial position, when the initial position rotates to the corresponding grinding wheel again, the grinding wheel corresponding to the current initial position stops working.

[0014] Optionally, after simultaneously polishing the edges of the wafer to be polished using multiple polishing wheels within corresponding step ranges, the method further includes:

[0015] After the grinding termination condition is met at the initial position, the wafer to be modified stops rotating after the initial position has rotated past the position corresponding to the last grinding wheel.

[0016] The present invention also provides a wafer edge finishing system, including a controller, a driving device and a plurality of grinding wheels; the grinding wheels have a corresponding step range for grinding, and the total step range formed by the step ranges of the plurality of grinding wheels corresponds to the finishing range of the wafer edge to be finished;

[0017] The driving device is used to drive the wafer to be modified and multiple grinding wheels to rotate relative to each other along the circumferential direction of the wafer to be modified.

[0018] The controller is used to grind the wafer from the initial position of the edge to be modified within the corresponding step range of the grinding wheel when the initial position of the edge of the wafer to be modified first moves to the position below the corresponding grinding wheel. After the initial position has rotated past the position corresponding to the last grinding wheel, the controller simultaneously modifies the edge of the wafer to be modified within the corresponding step range of multiple grinding wheels.

[0019] Optionally, the driving device includes a carrier disk and a driving shaft, with the driving shaft fixedly connected to the carrier disk; the carrier disk is used to carry the wafer to be modified, and the driving shaft is used to drive the carrier disk to rotate along the circumferential direction of the wafer to be modified.

[0020] Optionally, it includes four grinding wheels arranged circumferentially around the wafer to be modified.

[0021] Optionally, the four grinding wheels are evenly spaced along the circumference of the wafer to be modified.

[0022] The present invention provides a wafer edge finishing method, comprising driving a wafer to be finished and multiple grinding wheels to rotate relative to each other along the circumferential direction of the wafer to be finished; when the initial position of the edge of the wafer to be finished moves to the bottom of the corresponding grinding wheel for the first time, the grinding wheel grinds the wafer to be finished from the initial position within the step range corresponding to the grinding wheel, so that after rotating past the position corresponding to the last grinding wheel, the edge of the wafer to be finished is simultaneously finished by multiple grinding wheels within the corresponding step range; the total step range formed by the step ranges of the multiple grinding wheels corresponds to the finishing range of the edge of the wafer to be finished.

[0023] By setting multiple grinding wheels to perform edge finishing on the wafer from the same position as it rotates, and because the total step range formed by the step range of multiple grinding wheels corresponds to the finishing range of the wafer edge, each grinding wheel only grinds within its own step range, without needing to adjust the grinding position of the grinding wheel, thus effectively reducing processing time.

[0024] The present invention also provides a wafer edge modification system, which has the same beneficial effects as described above, and will not be described in detail here. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 as well as Figure 2 , Figure 1 This is a schematic diagram of wafer edge modification in the prior art;

[0027] Figure 2 This is a diagram of the wafer structure after edge modification;

[0028] Figure 3 This is a flowchart of a wafer edge modification method provided in an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of a wafer edge finishing system provided in an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of wafer grinding according to an embodiment of the present invention;

[0031] Figure 6 This is a flowchart illustrating a specific wafer edge modification method provided in an embodiment of the present invention. Detailed Implementation

[0032] The core of this invention is to provide a method for wafer edge modification. Please refer to [link / reference]. Figure 1 as well as Figure 2 , Figure 1 This is a schematic diagram of wafer edge modification in the prior art; Figure 2 This is a diagram of the wafer structure after edge modification. See also... Figure 1 as well as Figure 2 In current technologies, edge finishing processes primarily involve grinding the wafer edges using a grinding wheel (also known as a dicing blade). The grinding wheel gradually moves outward from the radius to be finished until it reaches the wafer edge, and the depth of penetration of the grinding wheel determines the edge finishing depth. Currently, processing wafer edges using a grinding wheel requires multiple reciprocating steps, necessitating the grinding wheel to adjust its position in multiple steps to complete the overall process. This makes the entire edge finishing process time-consuming.

[0033] The wafer edge finishing method provided by this invention includes driving the wafer to be finished and multiple grinding wheels to rotate relative to each other along the circumferential direction of the wafer to be finished; when the initial position of the edge of the wafer to be finished moves to the bottom of the corresponding grinding wheel for the first time, the grinding wheel grinds the wafer to be finished from the initial position within the step range corresponding to the grinding wheel, so that after rotating past the position corresponding to the last grinding wheel, the edge of the wafer to be finished is finished by multiple grinding wheels within the corresponding step range; the total step range formed by the step range of the multiple grinding wheels corresponds to the finishing range of the edge of the wafer to be finished.

[0034] By setting multiple grinding wheels to perform edge finishing on the wafer from the same position as it rotates, and because the total step range formed by the step range of multiple grinding wheels corresponds to the finishing range of the wafer edge, each grinding wheel only grinds within its own step range, without needing to adjust the grinding position of the grinding wheel, thus effectively reducing processing time.

[0035] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Please refer to Figures 3 to 5 , Figure 3 This is a flowchart of a wafer edge modification method provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of a wafer edge finishing system provided in an embodiment of the present invention; Figure 5This is a schematic diagram of wafer grinding according to an embodiment of the present invention.

[0037] See Figure 3 In this embodiment of the invention, the wafer edge finishing method includes:

[0038] S101: Drives the wafer to be modified and multiple grinding wheels to rotate relative to each other along the circumferential direction of the wafer to be modified.

[0039] In this step, the processor controls the drive device to drive the wafer to be modified and multiple polishing wheels to rotate relative to each other along the circumferential direction of the wafer. That is, in this step, the wafer to be modified can be driven to rotate only along its circumferential direction, multiple polishing wheels can be driven only along their circumferential direction, or both the wafer and multiple polishing wheels can be driven to rotate along their circumferential direction simultaneously, to achieve polishing of different locations on the wafer's edge. Of course, to simplify the structure, the drive device is typically only used to drive the wafer to be modified to rotate along its circumferential direction. Specifically, the drive device may include a carrier disk and a drive shaft, with the drive shaft fixedly connected to the carrier disk; the carrier disk carries the wafer to be modified, and the drive shaft drives the carrier disk to rotate along its circumferential direction. Besides the drive device with the above structure, other structures can also be used for driving, and no specific limitation is made here.

[0040] S102: When the initial position of the edge of the wafer to be modified moves to the bottom of the corresponding grinding wheel for the first time, the grinding wheel grinds the wafer to be modified from the initial position within the corresponding step range of the grinding wheel. After rotating past the position corresponding to the last grinding wheel, the edge of the wafer to be modified is simultaneously modified by multiple grinding wheels within the corresponding step range.

[0041] In this embodiment, the total step range formed by the step ranges of the multiple grinding wheels corresponds to the modification range of the edge of the wafer to be modified. The wafer to be modified has a preset initial position, which is the position where each grinding wheel begins grinding the wafer. Of course, this initial position can be the position on the wafer to be modified after the drive device rotates to a specific angle, or it can be the position where the first grinding wheel begins grinding.

[0042] In this embodiment, multiple grinding wheels are provided for each wafer to be modified, and these grinding wheels are obviously distributed along the circumference of the wafer. The multiple grinding wheels need to be connected to a controller so that the controller can control at least the start time of each grinding wheel, thereby ensuring that each grinding wheel can grind the wafer to be modified from its initial position.

[0043] Specifically, in this embodiment, the initial position passes through each grinding wheel sequentially according to the relative rotation direction of the wafer to be modified. In this step, the controller needs to control the grinding wheel to start grinding the wafer from the initial position when the initial position of the edge of the wafer to be modified first moves under a certain grinding wheel. As the wafer to be modified continues to rotate relative to each other, the initial position passes through each grinding wheel sequentially along the rotation direction. The controller will then control each grinding wheel to start grinding sequentially. After the initial position has rotated past the position corresponding to the last grinding wheel along the rotation direction, multiple grinding wheels will work simultaneously, that is, the edge of the wafer to be modified will be modified simultaneously through multiple grinding wheels.

[0044] In this embodiment, each grinding wheel grinds the wafer to be ground within its corresponding step range. This step range is the area on the wafer surface that the grinding wheel can grind without needing to adjust its step size. Each grinding wheel in this embodiment has its own step range, and the total step range formed by the step ranges of multiple grinding wheels corresponds to the entire modification range of the wafer edge. Therefore, in this embodiment, it is not necessary to control the grinding wheel to move in a stepping motion or adjust its grinding position to achieve the modification of the wafer edge.

[0045] The stepping ranges of the various grinding wheels mentioned above may or may not overlap; no specific limitation is made here, as long as the total stepping range corresponds to the entire refinishing area. See also Figure 4 as well as Figure 5 In this embodiment, four grinding wheels are typically provided, arranged circumferentially around the wafer to be modified. The four grinding wheels are usually evenly spaced along the circumference of the wafer. However, any two of the multiple step ranges corresponding to the aforementioned grinding wheels do not completely overlap; that is, each grinding wheel grinds the areas that were not previously ground during operation.

[0046] In existing technologies, edge finishing with a depth of 100µm and a width of 2.5mm typically requires the polishing wheel to move three times from the inside to the wafer edge, totaling four steps to complete the finishing process. This embodiment, however, uses four polishing wheels, adjusting their positions to be precisely at the four locations of a single polishing wheel. Through the aforementioned steps, the four polishing wheels can start working sequentially, simultaneously polishing a single wafer, thus reducing processing time.

[0047] The wafer edge finishing method provided in this embodiment of the invention uses multiple grinding wheels to finish the edge of the wafer from the same position as the wafer rotates. Since the total step range formed by the step range of the multiple grinding wheels corresponds to the finishing range of the edge of the wafer, each grinding wheel only grinds within its own step range, without needing to adjust the grinding position of the grinding wheel, thereby effectively reducing the processing time.

[0048] The specific details of the wafer edge modification method provided by this invention will be described in detail in the following embodiments.

[0049] Please refer to Figure 6 , Figure 6 This is a flowchart illustrating a specific wafer edge modification method provided in an embodiment of the present invention.

[0050] See Figure 6 In this embodiment of the invention, the wafer edge finishing method includes:

[0051] S201: Drive the wafer to be modified and multiple grinding wheels to rotate relative to each other along the circumferential direction of the wafer to be modified.

[0052] S202: When the initial position of the edge of the wafer to be modified moves to the bottom of the corresponding grinding wheel for the first time, the grinding wheel grinds the wafer to be modified from the initial position within the corresponding step range of the grinding wheel. After rotating past the position corresponding to the last grinding wheel, the edge of the wafer to be modified is simultaneously modified by multiple grinding wheels within the corresponding step range.

[0053] The above S201 to S202 are basically the same as S101 to S102 in the above embodiments of the invention. For details, please refer to the above embodiments of the invention. They will not be repeated here.

[0054] S203: After the grinding termination condition is met at the initial position, when the initial position rotates to the corresponding grinding wheel again, the grinding wheel corresponding to the current initial position stops working.

[0055] The aforementioned grinding termination condition can be either that the initial position has rotated a preset number of revolutions, or that the grinding depth detected at the initial position has reached a preset depth. The grinding termination condition can be set according to actual conditions and is not specifically limited here. When the initial position meets the grinding termination condition, it means that for a given grinding wheel, the wafer to be ground will complete grinding within its step range after one more revolution. Therefore, in this step, when the initial position rotates to the corresponding grinding wheel again, the rotation of that corresponding grinding wheel will stop. At this time, as the wafer to be ground continues to rotate, the initial position will pass through each grinding wheel in sequence, thereby stopping the operation of each grinding wheel in turn.

[0056] S204: After the grinding termination condition is met at the initial position, the wafer to be modified stops rotating after the initial position has rotated past the position corresponding to the last grinding wheel.

[0057] In this step, once the initial position has rotated past the position corresponding to the last grinding wheel, it means that the grinding of the entire modification area of ​​the wafer to be modified has been completed. At this point, the rotation of the wafer to be modified will stop, completing the edge modification of the wafer.

[0058] The wafer edge finishing method provided in this embodiment of the invention uses multiple grinding wheels to finish the edge of the wafer from the same position as the wafer rotates. Since the total step range formed by the step range of the multiple grinding wheels corresponds to the finishing range of the edge of the wafer, each grinding wheel only grinds within its own step range, without needing to adjust the grinding position of the grinding wheel, thereby effectively reducing the processing time.

[0059] The following describes a wafer edge modification system provided by an embodiment of the present invention. The wafer edge modification system described below can be referred to in correspondence with the wafer edge modification method described above.

[0060] Reference Figure 4 as well as Figure 5 A wafer edge finishing system may include a controller, a drive unit, and multiple grinding wheels. Each grinding wheel has a corresponding grinding step range, and the total step range formed by the combined step ranges of the multiple grinding wheels corresponds to the finishing range of the wafer edge to be finished. The drive unit drives the wafer to be finished and the multiple grinding wheels to rotate relative to each other along the circumferential direction of the wafer. The controller, when the initial position of the wafer edge to be finished moves to below the corresponding grinding wheel for the first time, grinds the wafer from the initial position within the corresponding step range of the grinding wheel, so that after rotating past the position corresponding to the last grinding wheel at the initial position, the multiple grinding wheels simultaneously finish the edge of the wafer within the corresponding step range.

[0061] The controller described above is used to execute the wafer edge finishing method provided in the above embodiments of the invention. Its specific details have been described in detail in the above embodiments and will not be repeated here. In this embodiment, the driving device is used to drive the wafer to be finished and multiple grinding wheels to rotate relative to each other along the circumferential direction of the wafer to be finished, i.e., to implement the specific steps in S101 and S102 described above. Its specific details have been described in detail in the above embodiments of the invention, and the specific details regarding the grinding wheels have also been described in detail in the above embodiments of the invention and will not be repeated here.

[0062] Specifically, in this embodiment, the driving device includes a carrier disk and a driving shaft, with the driving shaft fixedly connected to the carrier disk; the carrier disk is used to carry the wafer to be modified, and the driving shaft is used to drive the carrier disk to rotate along the circumferential direction of the wafer to be modified, so as to drive the wafer to be modified to rotate along its axial direction.

[0063] Specifically, in this embodiment, the wafer edge finishing system includes four grinding wheels, which are arranged circumferentially around the wafer to be finished.

[0064] Specifically, in this embodiment, the four grinding wheels are evenly spaced along the circumference of the wafer to be modified.

[0065] Specifically, in this embodiment, any two step ranges do not completely overlap.

[0066] Specifically, in this embodiment, the processor is also used to stop the grinding wheel corresponding to the current initial position from working when the initial position rotates to the corresponding grinding wheel again after the grinding termination condition is met at the initial position.

[0067] Specifically, in this embodiment, the processor is also used to stop rotating the wafer to be modified after the initial position has been satisfied with the grinding termination condition and the initial position has rotated past the position corresponding to the last grinding wheel.

[0068] The wafer edge modification system of this embodiment is used to implement the aforementioned wafer edge modification method. Therefore, the specific implementation of the wafer edge modification system can be found in the embodiment section of the wafer edge modification method above. Thus, the specific implementation can be referred to the description of the corresponding embodiments, which will not be repeated here.

[0069] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0070] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0071] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0072] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0073] The foregoing has provided a detailed description of a wafer edge modification method and a wafer edge modification system provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for modifying the edge of a wafer, characterized in that, include: The wafer to be modified is driven to rotate relative to multiple grinding wheels along the circumferential direction of the wafer to be modified; When the initial position of the edge of the wafer to be modified moves to the position below the corresponding grinding wheel for the first time, the grinding wheel grinds the wafer from the initial position within the corresponding step range of the grinding wheel. After rotating past the position corresponding to the last grinding wheel at the initial position, multiple grinding wheels simultaneously modify the edge of the wafer within the corresponding step range. The step range is the range within which the grinding wheel grinds the surface of the wafer when no step adjustment is required. The total step range formed by the step ranges of multiple grinding wheels corresponds to the modification range of the edge of the wafer to be modified. After the grinding termination condition is met at the initial position, when the initial position rotates to the corresponding grinding wheel again, the grinding wheel corresponding to the current initial position stops working; It includes four grinding wheels, which are arranged circumferentially around the wafer to be modified; After simultaneously polishing the edges of the wafer to be polished using multiple polishing wheels within corresponding step ranges, the process further includes: After the grinding termination condition is met at the initial position, the wafer to be modified stops rotating after the initial position has rotated past the position corresponding to the last grinding wheel.

2. The method according to claim 1, characterized in that, The four grinding wheels are evenly spaced along the circumference of the wafer to be modified.

3. The method according to claim 1, characterized in that, Any two of the multiple step ranges do not completely overlap.

4. A wafer edge finishing system, characterized in that, It includes a controller, a drive unit, and multiple grinding wheels; each grinding wheel has a corresponding grinding step range, which is the range on the surface of the wafer to be ground when the grinding wheel does not need to be adjusted in step, and the total step range formed by the step ranges of multiple grinding wheels corresponds to the modification range of the edge of the wafer to be modified. The driving device is used to drive the wafer to be modified and multiple grinding wheels to rotate relative to each other along the circumferential direction of the wafer to be modified. The controller is used to grind the wafer to be modified from the initial position of the edge of the wafer to be modified within the corresponding step range of the grinding wheel when the initial position of the edge of the wafer to be modified first moves to the position below the corresponding grinding wheel. After the initial position has rotated past the position corresponding to the last grinding wheel, the controller simultaneously modifies the edge of the wafer to be modified within the corresponding step range of multiple grinding wheels. After the grinding termination condition is met at the initial position, when the initial position rotates to the corresponding grinding wheel again, the grinding wheel corresponding to the current initial position stops working; It includes four grinding wheels, which are arranged circumferentially around the wafer to be modified; The controller is also used for: After the grinding termination condition is met at the initial position, the wafer to be modified stops rotating after the initial position has rotated past the position corresponding to the last grinding wheel.

5. The wafer edge finishing system according to claim 4, characterized in that, The driving device includes a carrier disk and a driving shaft, with the driving shaft fixedly connected to the carrier disk; the carrier disk is used to carry the wafer to be modified, and the driving shaft is used to drive the carrier disk to rotate along the circumferential direction of the wafer to be modified.

6. The wafer edge finishing system according to claim 4, characterized in that, The four grinding wheels are evenly spaced along the circumference of the wafer to be modified.

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