Methods for compensating for overprinting deviation
By performing pre-compensation on the lithography machine, the overlay deviation compensation process of the lithography machine is simplified, the problem of insufficient pattern overlay accuracy in the lithography process is solved, and the compensation efficiency and accuracy of the lithography machine are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SEMICON MFG INT (SHANGHAI) CORP
- Filing Date
- 2022-09-21
- Publication Date
- 2026-05-26
AI Technical Summary
In existing technologies, the overlay accuracy of patterns transferred onto silicon wafers during photolithography is insufficient, resulting in a complex and costly compensation process for photolithography machines. Furthermore, a large compensation at one time may exceed the compensation range of the photolithography machine, making accurate compensation impossible.
Before forming the initial fin structure, the first etching deviation of the initial fin structure is obtained by performing the first and second pre-compensation on the lithography machine. The third and fourth pre-compensation are then performed based on this deviation to ensure that the first etching deviation of the initial fin structure is the same as the second pre-compensation value and that the sum of the fourth pre-compensation value and the second pre-compensation value is 0. This simplifies the number of layers that the etching deviation is passed down and reduces the compensation value of the lithography machine.
It simplifies the compensation process of the lithography machine, improves the compensation efficiency, avoids situations where the compensation value is too large and therefore unlikely to occur, and enhances the debugging efficiency of the lithography machine.
Smart Images
Figure CN117784528B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductors, and more particularly to a method for compensating for overlay misalignment. Background Technology
[0002] Photolithography is a crucial technology in semiconductor manufacturing, enabling the transfer of patterns from a photomask to the surface of a silicon wafer, forming semiconductor products that meet design requirements. In the photolithography process, firstly, through an exposure step, light passes through the transparent or reflective areas of the photomask and illuminates the silicon wafer coated with photoresist, causing a photochemical reaction with the photoresist. Next, through a development step, the solubility of the developer by the photosensitive and unphotosensitive photoresist forms a photolithographic pattern, achieving the transfer of the photomask pattern. Then, through an etching step, the silicon wafer is etched based on the photolithographic pattern formed by the photoresist layer, further transferring the photomask pattern onto the silicon wafer.
[0003] However, the overlay accuracy of the patterns transferred onto the silicon wafer still needs improvement. Summary of the Invention
[0004] The technical problem solved by this invention is to provide a method for compensating for overlay deviations, so as to improve the overlay accuracy of patterns transferred onto silicon wafers.
[0005] To solve the above-mentioned technical problems, the present invention provides a method for compensating overlay deviation, comprising: providing a wafer; performing a first pre-compensation and a second pre-compensation on a lithography machine; after performing the first pre-compensation and the second pre-compensation on the lithography machine, forming an initial fin structure on the wafer, wherein the sum of the compensation value of the first pre-compensation and the previous first etching deviation of the initial fin structure is 0; obtaining a first etching deviation of the initial fin structure, wherein the first etching deviation is the same as the compensation value of the second pre-compensation; performing a third compensation on the lithography machine according to the first etching deviation; performing a fourth pre-compensation on the lithography machine; after performing the third compensation and the fourth pre-compensation on the lithography machine, partially etching the initial fin structure to form a fin structure, wherein the sum of the compensation value of the fourth pre-compensation and the compensation value of the second pre-compensation is 0, wherein the compensation value of the second pre-compensation is the same as the previous second etching deviation of the fin structure; obtaining a second etching deviation of the fin structure, wherein the value of the second etching deviation is 0.
[0006] Optionally, the method for obtaining the previous first etching deviation includes: forming a first photoresist pattern on a wafer; aligning the photolithography machine and measuring and obtaining the position and size information of the first photoresist pattern; using the first photoresist pattern as a mask, forming an initial fin structure on the wafer; measuring and obtaining the position and size information of the initial fin structure; obtaining a first difference between the position and size information of the first photoresist pattern and the position and size information of the initial fin structure, wherein the first difference is the previous first etching deviation.
[0007] Optionally, the method for obtaining the previous second etching deviation includes: forming a second photoresist pattern on the initial fin structure; aligning the photolithography machine and obtaining the position and size information of the second photoresist pattern; etching the initial fin structure using the second photoresist pattern as a mask to form the fin structure on the wafer; measuring and obtaining the position and size information of the fin structure; obtaining a second difference between the position and size information of the second photoresist pattern and the position and size information of the fin structure, wherein the second difference is the previous second etching deviation.
[0008] Optionally, after forming the fin structure, the method further includes: performing a fifth compensation on the lithography machine; after performing the fifth compensation on the lithography machine, forming a gate structure on the fin structure, the gate structure spanning the fin structure, and the sum of the compensation value of the fifth compensation and the previous third etching deviation of the gate structure being 0.
[0009] Optionally, the method for obtaining the previous third etching deviation includes: forming a third photoresist pattern on the fin structure; aligning the photolithography machine and obtaining the position and size information of the third photoresist pattern; using the third photoresist pattern as a mask to form a gate structure on the fin structure; measuring and obtaining the position and size information of the gate structure; obtaining a third difference between the position and size information of the third photoresist pattern and the position and size information of the gate structure, wherein the third difference is the previous third etching deviation.
[0010] Optionally, it also includes: obtaining a third etching deviation of the gate structure, wherein the value of the third etching deviation is 0.
[0011] Optionally, it also includes: forming a metal layer on the gate structure; and before forming the metal layer, the compensation value for compensating the lithography machine is 0.
[0012] Optionally, it also includes: obtaining a fourth etching deviation of the metal layer, wherein the value of the fourth etching deviation is 0.
[0013] Optionally, the method for obtaining the first etching deviation of the initial fin structure includes: obtaining the difference between the positional and dimensional information between the photoresist pattern and the initial fin structure pattern, that is, obtaining the first etching deviation of the initial fin structure.
[0014] Optionally, the method for obtaining the second etching deviation of the fin structure includes: obtaining the difference between the positional and dimensional information between the photoresist pattern and the fin structure pattern, that is, obtaining the second etching deviation of the fin structure.
[0015] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:
[0016] The present invention provides a method for compensating overlay deviations. Before forming the initial fin structure, the lithography machine undergoes a first pre-compensation and a second pre-compensation. The sum of the compensation value of the first pre-compensation and the previous first etching deviation of the initial fin structure is 0, and the compensation value of the second pre-compensation is the same as the previous second etching deviation of the fin structure. Therefore, the first etching deviation of the formed initial fin structure is the same as the compensation value of the second pre-compensation. After the first etching deviation is passed to the fin structure layer, since the sum of the compensation value of the fourth pre-compensation and the compensation value of the second pre-compensation is 0, the sum of the compensation values of the third compensation and the fourth pre-compensation is also 0. Consequently, the value of the second etching deviation of the fin structure obtained subsequently is also 0. When forming the subsequent gate structure, it is not necessary to compensate the lithography machine based on the second etching deviation of the fin structure. This simplifies the number of layers through which the first and second etching deviations are passed down, simplifies the compensation process, results in smaller compensation values, and makes it easier for the lithography machine to adjust and compensate. It avoids situations where the compensation value is too large and compensation is difficult to achieve, thus improving compensation efficiency. Attached Figure Description
[0017] Figure 1 This is a flowchart illustrating the compensation method for overlay deviation in an embodiment of the present invention. Detailed Implementation
[0018] As described in the background section, the overlay accuracy of patterns transferred onto silicon wafers still needs improvement.
[0019] Specifically, when forming a multi-layer structure on a wafer, the etching deviation of the previous layer needs to be compensated for during the formation of the next layer. For example, the following processes are performed sequentially on the wafer: forming an initial fin structure, removing part of the initial fin structure to form a fin structure, forming a gate structure on the fin structure, and forming a metal layer on the gate structure. After forming the initial fin structure, the etching deviation of the initial fin structure is obtained. This etching deviation is passed to the next layer. That is, after forming the fin structure, the sum of the etching deviations of the initial fin structure and the fin structure is obtained. Similarly, after forming the gate structure, the sum of the etching deviations of the initial fin structure, the fin structure, and the gate structure is obtained. This sum of the etching deviations of the initial fin structure, the fin structure, and the gate structure is passed to the formation of the metal layer. The lithography machine needs to compensate for these etching deviations based on the sum of the etching deviations of the initial fin structure, the fin structure, and the gate structure.
[0020] However, due to the etching process, the fin structure or gate structure at the edge of the wafer is prone to tilting and significant deviations. These deviations are propagated layer by layer as the pattern is transferred, leading to situations where a large compensation is required from the lithography machine during metal layer formation. On one hand, performing a large compensation at once requires significant adjustments to the lithography machine, resulting in substantial costs. On the other hand, a large compensation at once may exceed the lithography machine's compensation range, making accurate compensation impossible.
[0021] To address the aforementioned issues, a common approach is to pre-compensate the lithography machine starting from the second layer. For example, when forming the photoresist pattern to remove part of the initial fin structure, compensation for the etching deviation of the initial fin structure and pre-compensation for the fin structure are performed. The compensation value for the pre-compensation is the negative value of the etching deviation of the fin structure. This ensures that after forming the fin structure, only the etching deviation of the initial fin structure is obtained, not the etching deviation of the fin structure itself. The pre-compensation cancels out the etching deviation of the fin structure. Next, the gate is formed on the fin structure. When patterning the photoresist on the gate structure, only initial fin etching deviation compensation and gate structure pre-compensation are needed for the lithography machine. The pre-compensation value for the gate structure is a negative of the gate structure etching deviation. This ensures that after the gate structure is formed, only the initial fin etching deviation is obtained, not the gate structure etching deviation; the pre-compensation cancels out the gate structure etching deviation. When forming the photoresist pattern on the gate structure, only initial fin etching deviation compensation is needed; no further compensation for either the fin or gate structure etching deviation is required. Both the fin and gate structure pre-compensation values are empirical measurements. This process reduces the compensation value for the lithography machine; however, the compensation process is slightly more complex.
[0022] To address the aforementioned problems, this invention provides a method for compensating overlay deviations. Before forming the initial fin structure, the lithography machine undergoes a first pre-compensation and a second pre-compensation. The sum of the compensation value of the first pre-compensation and the previous first etching deviation of the initial fin structure is 0, and the compensation value of the second pre-compensation is the same as the previous second etching deviation of the fin structure. Therefore, the first etching deviation of the formed initial fin structure is the same as the compensation value of the second pre-compensation. After the first etching deviation is passed to the fin structure layer, since the sum of the compensation value of the fourth pre-compensation and the compensation value of the second pre-compensation is 0, the sum of the compensation values of the third compensation and the fourth pre-compensation is also 0. Consequently, the value of the second etching deviation of the fin structure obtained subsequently is also 0. When forming the subsequent gate structure, it is not necessary to compensate the lithography machine based on the second etching deviation of the fin structure. This simplifies the number of layers through which the first and second etching deviations are passed down, simplifies the compensation process, results in smaller compensation values, and makes it easier for the lithography machine to adjust and compensate. It avoids situations where the compensation value is too large and compensation is difficult to achieve, thus improving compensation efficiency.
[0023] To make the above-mentioned objectives, features and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0024] Figure 1 This is a flowchart illustrating the compensation method for overlay deviation in an embodiment of the present invention.
[0025] Please refer to Figure 1 The compensation method for the overlay deviation includes:
[0026] Step S10: Provide a wafer;
[0027] Step S20: Perform first pre-compensation and second pre-compensation on the lithography machine;
[0028] Step S30: After performing the first pre-compensation and the second pre-compensation on the lithography machine, an initial fin structure is formed on the wafer. The sum of the compensation value of the first pre-compensation and the previous first etching deviation of the initial fin structure is 0.
[0029] Step S40: Obtain the first etching deviation of the initial fin structure, wherein the first etching deviation is the same as the compensation value of the second pre-compensation;
[0030] Step S50: Perform a third compensation on the lithography machine based on the first etching deviation;
[0031] Step S60: Perform the fourth pre-compensation on the lithography machine;
[0032] Step S70: After performing the third compensation and the fourth pre-compensation on the lithography machine, the initial fin structure is partially etched to form the fin structure. The sum of the compensation value of the fourth pre-compensation and the compensation value of the second pre-compensation is 0, and the sum of the compensation value of the fourth pre-compensation and the second etching deviation of the previous fin structure is 0.
[0033] Step S80: Obtain the second etching deviation of the fin structure, where the value of the second etching deviation is 0.
[0034] The method for compensating overlay deviation involves performing a first pre-compensation and a second pre-compensation on the lithography machine before forming the initial fin structure. The sum of the compensation value of the first pre-compensation and the previous first etching deviation of the initial fin structure is 0, and the compensation value of the second pre-compensation is the same as the previous second etching deviation of the fin structure. Therefore, the first etching deviation of the formed initial fin structure is the same as the compensation value of the second pre-compensation. After the first etching deviation is passed to the fin structure layer, since the sum of the compensation value of the fourth pre-compensation and the compensation value of the second pre-compensation is 0, the sum of the compensation values of the third compensation and the fourth pre-compensation is also 0. Consequently, the value of the second etching deviation of the fin structure obtained subsequently is also 0. When forming the subsequent gate structure, it is not necessary to compensate the lithography machine based on the second etching deviation of the fin structure. This simplifies the number of layers through which the first and second etching deviations are passed down, simplifies the compensation process, results in smaller compensation values, and makes it easier for the lithography machine to adjust and compensate. It avoids situations where the compensation value is too large and compensation is difficult to achieve, thus improving compensation efficiency.
[0035] Next, each step will be analyzed and explained.
[0036] Please continue to refer to this. Figure 1 Step S10: Provide a wafer.
[0037] The wafers mentioned are mass-produced wafers in semiconductor manufacturing processes, which will not be described in detail here.
[0038] Please continue to refer to this. Figure 1 Step S20: Perform first pre-compensation and second pre-compensation on the lithography machine.
[0039] Before the initial fin structure is formed, the lithography machine is pre-compensated and pre-compensated in the first and second stages. This simplifies the number of layers that the first and second etching deviations are passed down, thus simplifying the compensation process and avoiding situations where the compensation value is too large and compensation is difficult to occur.
[0040] Please continue to refer to this. Figure 1 Step S30: After performing the first pre-compensation and the second pre-compensation on the lithography machine, an initial fin structure is formed on the wafer. The sum of the compensation value of the first pre-compensation and the previous first etching deviation of the initial fin structure is 0.
[0041] The initial etching deviation of the initial fin structure is the empirical result of multiple experimental measurements.
[0042] The method for obtaining the previous first etching deviation includes: forming a first photoresist pattern on a wafer; aligning the photolithography machine and measuring and obtaining the position and size information of the first photoresist pattern; using the first photoresist pattern as a mask, forming an initial fin structure on the wafer; measuring and obtaining the position and size information of the initial fin structure; obtaining a first difference between the position and size information of the first photoresist pattern and the position and size information of the initial fin structure, wherein the first difference is the previous first etching deviation.
[0043] The first photoresist pattern is the pattern after exposure and development.
[0044] Please continue to refer to this. Figure 1 Step S40: Obtain the first etching deviation of the initial fin structure, wherein the first etching deviation is the same as the compensation value of the second pre-compensation.
[0045] The method for obtaining the first etching deviation of the initial fin structure includes: obtaining the difference in positional and dimensional information between the photoresist pattern and the initial fin structure pattern, i.e., obtaining the first etching deviation of the initial fin structure. The process for obtaining the first etching deviation of the initial fin structure is the same as the process for obtaining the previous first etching deviation of the initial fin structure, and will not be described again here.
[0046] Since the sum of the compensation value of the first pre-compensation and the previous first etching deviation of the initial fin structure is 0, when the first pre-compensation and the second pre-compensation are passed to the initial fin structure, the compensation value of the first pre-compensation is canceled by the original first etching deviation of the initial fin structure. At this time, the first etching deviation of the initial fin structure is the same as the compensation value of the second pre-compensation.
[0047] Please continue to refer to this. Figure 1 Step S50: Perform third compensation on the lithography machine based on the first etching deviation.
[0048] The compensation value of the third compensation is the first etching deviation, that is, the compensation value of the third compensation is the compensation value of the second pre-compensation.
[0049] Please continue to refer to this. Figure 1 Step S60: Perform the fourth pre-compensation on the lithography machine.
[0050] Please continue to refer to this. Figure 1Step S70: After performing the third compensation and the fourth pre-compensation on the lithography machine, the initial fin structure is partially etched to form the fin structure. The sum of the compensation value of the fourth pre-compensation and the compensation value of the second pre-compensation is 0, and the sum of the compensation value of the fourth pre-compensation and the previous second etching deviation of the fin structure is 0.
[0051] The previous second etching deviation of the fin structure is the empirical result after multiple experimental measurements.
[0052] The method for obtaining the previous second etching deviation includes: forming a second photoresist pattern on the initial fin structure; aligning the photolithography machine and obtaining the position and size information of the second photoresist pattern; etching the initial fin structure using the second photoresist pattern as a mask to form the fin structure on the wafer; measuring and obtaining the position and size information of the fin structure; obtaining a second difference between the position and size information of the second photoresist pattern and the position and size information of the fin structure, wherein the second difference is the previous second etching deviation.
[0053] The second photoresist pattern is the pattern after exposure and development.
[0054] The sum of the compensation value of the fourth pre-compensation and the compensation value of the second pre-compensation is 0, and the sum of the compensation value of the fourth pre-compensation and the previous second etching deviation of the fin structure is 0. That is, the sum of the compensation value of the fourth pre-compensation and the compensation value of the third compensation is 0. Thus, the third compensation and the fourth pre-compensation cancel each other out. In other words, no compensation is required for the lithography machine before the fin structure is formed, which simplifies the compensation process.
[0055] Please continue to refer to this. Figure 1 Step S80: Obtain the second etching deviation of the fin structure, where the value of the second etching deviation is 0.
[0056] The method for obtaining the second etching deviation of the fin structure includes: obtaining the difference between the positional and dimensional information between the photoresist pattern and the fin structure pattern, that is, obtaining the second etching deviation of the fin structure.
[0057] The process of obtaining the second etching deviation of the fin structure is the same as the process of obtaining the previous second etching deviation of the fin structure, and will not be repeated here.
[0058] Since no compensation is required for the lithography machine before the fin structure is formed, the etching deviation transmitted to the fin structure is 0.
[0059] In this embodiment, after forming the fin structure, the method further includes: performing a fifth compensation on the lithography machine; after performing the fifth compensation on the lithography machine, forming a gate structure on the fin structure, the gate structure spanning the fin structure, and the sum of the compensation value of the fifth compensation and the previous third etching deviation of the gate structure being 0.
[0060] In this embodiment, the method for obtaining the previous third etching deviation includes: forming a third photoresist pattern on the fin structure; aligning the photolithography machine and obtaining the position and size information of the third photoresist pattern; using the third photoresist pattern as a mask to form a gate structure on the fin structure; measuring and obtaining the position and size information of the gate structure; obtaining a third difference between the position and size information of the third photoresist pattern and the position and size information of the gate structure, wherein the third difference is the previous third etching deviation.
[0061] The previous third etching deviation of the gate structure is the empirical result after multiple experimental measurements.
[0062] The third photoresist pattern is the pattern after exposure and development.
[0063] The sum of the compensation value of the fifth compensation and the previous third etching deviation of the gate structure is 0. That is, before forming the gate structure, only the lithography machine needs to be compensated for the fifth compensation. The compensation value of the fifth compensation is small, which simplifies the compensation process.
[0064] In this embodiment, the method further includes: obtaining a third etching deviation of the gate structure, wherein the value of the third etching deviation is 0.
[0065] The process for obtaining the third etching deviation of the gate structure is the same as that for the previous third etching deviation of the gate structure, and will not be repeated here.
[0066] The sum of the fifth compensation value and the previous third etching deviation of the gate structure is 0. Therefore, the fifth compensation value is canceled out by the original third etching deviation of the gate structure, and the third etching deviation of the gate structure is 0. There is no need to propagate the third etching deviation of the gate structure downwards further.
[0067] In this embodiment, the method further includes: forming a metal layer on the gate structure; and before forming the metal layer, the compensation value for the lithography machine is 0.
[0068] The third etch deviation of the gate structure is 0, so there is no need to pass the third etch deviation to the process of forming the metal layer.
[0069] In this embodiment, the method further includes: obtaining a fourth etching deviation of the metal layer, wherein the value of the fourth etching deviation is 0.
[0070] Since no compensation is required for the lithography machine before the metal layer is formed, the etching deviation transmitted to the metal layer is 0.
[0071] The above-mentioned compensation process for overlay deviations has been simplified, making it easier for the lithography machine to compensate and improving production efficiency.
[0072] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.
Claims
1. A method for compensating for overprinting deviation, characterized in that, include: Provide wafers; Perform first and second pre-compensation on the lithography machine; After performing the first pre-compensation and the second pre-compensation on the lithography machine, an initial fin structure is formed on the wafer. The sum of the compensation value of the first pre-compensation and the previous first etching deviation of the initial fin structure is 0. The first etching deviation of the initial fin structure is obtained, and the first etching deviation is the same as the compensation value of the second pre-compensation. The lithography machine is compensated a third time based on the first etching deviation; Perform a fourth pre-compensation on the lithography machine; After performing the third and fourth pre-compensation on the lithography machine, the initial fin structure is partially etched to form the fin structure. The sum of the compensation value of the fourth pre-compensation and the compensation value of the second pre-compensation is 0. The compensation value of the second pre-compensation is the same as the previous second etching deviation of the fin structure. The second etching deviation of the fin structure is obtained, and the value of the second etching deviation is 0.
2. The method for compensating overprinting deviation as described in claim 1, characterized in that, The method for obtaining the previous first etching deviation includes: forming a first photoresist pattern on a wafer; aligning the photolithography machine and measuring and obtaining the position and size information of the first photoresist pattern; using the first photoresist pattern as a mask, forming an initial fin structure on the wafer; measuring and obtaining the position and size information of the initial fin structure; obtaining a first difference between the position and size information of the first photoresist pattern and the position and size information of the initial fin structure, wherein the first difference is the previous first etching deviation.
3. The method for compensating overprinting deviation as described in claim 1, characterized in that, The method for obtaining the previous second etching deviation includes: forming a second photoresist pattern on the initial fin structure; aligning the photolithography machine and obtaining the position and size information of the second photoresist pattern; etching the initial fin structure using the second photoresist pattern as a mask to form the fin structure on the wafer; measuring and obtaining the position and size information of the fin structure; obtaining a second difference between the position and size information of the second photoresist pattern and the position and size information of the fin structure, wherein the second difference is the previous second etching deviation.
4. The method for compensating overprinting deviation as described in claim 1, characterized in that, After forming the fin structure, the process further includes: performing a fifth compensation on the lithography machine; after performing the fifth compensation on the lithography machine, forming a gate structure on the fin structure, the gate structure spanning the fin structure, and the sum of the compensation value of the fifth compensation and the previous third etching deviation of the gate structure being 0.
5. The method for compensating overprinting deviation as described in claim 4, characterized in that, The method for obtaining the previous third etching deviation includes: forming a third photoresist pattern on the fin structure; aligning the photolithography machine and obtaining the position and size information of the third photoresist pattern; using the third photoresist pattern as a mask to form a gate structure on the fin structure; measuring and obtaining the position and size information of the gate structure; obtaining a third difference between the position and size information of the third photoresist pattern and the position and size information of the gate structure, wherein the third difference is the previous third etching deviation.
6. The method for compensating overprinting deviation as described in claim 4, characterized in that, Also includes: The third etching deviation of the gate structure is obtained, and the value of the third etching deviation is 0.
7. The method for compensating overprinting deviation as described in claim 4, characterized in that, Also includes: A metal layer is formed on the gate structure; before the metal layer is formed, the compensation value for the lithography machine is 0.
8. The method for compensating for overlay deviation as described in claim 7, characterized in that, Also includes: The fourth etching deviation of the metal layer is obtained, and the value of the fourth etching deviation is 0.
9. The method for compensating overprinting deviation as described in claim 1, characterized in that, The method for obtaining the first etching deviation of the initial fin structure includes: obtaining the difference between the positional and dimensional information between the photoresist pattern and the initial fin structure pattern, that is, obtaining the first etching deviation of the initial fin structure.
10. The method for compensating overprinting deviation as described in claim 1, characterized in that, The method for obtaining the second etching deviation of the fin structure includes: obtaining the difference between the positional and dimensional information between the photoresist pattern and the fin structure pattern, that is, obtaining the second etching deviation of the fin structure.