Optical proximity correction, photomask production and patterning methods

Abstract

An optical proximity correction, photomask production and patterning method, wherein the optical proximity correction method includes: providing a target pattern; increasing the side length of the target pattern to form an initial pattern; correcting the initial pattern to obtain a corresponding first correction pattern; forming an auxiliary pattern, the auxiliary pattern surrounding the first correction pattern; comparing the difference factor between the first correction pattern and the auxiliary pattern; if the value of the difference factor is greater than a predetermined threshold, increasing the area of ​​the target pattern corresponding to the first correction pattern to form a corrected target pattern; performing process correction on the first correction pattern to obtain a corresponding process correction pattern; repeating the above steps of comparing the difference factor until the correction meets the predetermined number of times; performing final correction on the formed first correction pattern and the process correction pattern to obtain a correction pattern. The present invention ensures the accuracy of transferring the photolithography pattern to the wafer and ensures that the formed semiconductor device can meet the designed size requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and particularly to an optical proximity correction, photomask manufacturing and patterning method. Background Art

[0002] With the rapid development of semiconductor manufacturing technology, in order for semiconductor devices to achieve faster computing speeds, larger data storage capacities, and more functions, semiconductor chips are developing towards higher integration levels. The higher the integration level of semiconductor chips, the smaller the critical dimension (CD, Critical Dimension) of semiconductor devices.

[0003] However, due to the influence of the resolution limit of the optical exposure tool, when exposing and transferring these densely arranged mask circuit patterns onto the wafer, it is very easy to generate optical proximity effects (OPE, optical proximity effect). For example, right-angled corner rounding, line end shortening, and line width increase / decrease are all defects in the transfer of mask circuit patterns onto the wafer caused by common optical proximity effects.

[0004] In order to correct the OPE phenomenon, OPC (Optical Proximity Correction) has emerged. The core idea of OPC is to establish an OPC model based on the consideration of offsetting the OPE phenomenon, and design the photomask pattern according to the OPC model. Although the photolithography pattern after photolithography has the OPC phenomenon relative to the photomask pattern, since the offset of this phenomenon has been considered when designing the photomask pattern according to the OPC model, the photolithography pattern after photolithography is close to the target pattern that the user actually hopes to obtain.

[0005] However, in the manufacturing process of integrated circuits, after the photolithography pattern is formed, it is still necessary to transfer the photolithography pattern onto the wafer to form the final pattern. The fact that the photolithography pattern after photolithography is close to the target pattern that the user actually hopes to obtain does not mean that the pattern formed on the wafer subsequently is close to the above target pattern. Compared with the target pattern, the accuracy of the final pattern formed on the wafer in the prior art still needs to be improved. Summary of the Invention

[0006] The problem to be solved by the present invention is to provide an optical proximity correction, photomask manufacturing and patterning method to ensure the accuracy of lithographic pattern transfer onto a wafer and ensure that the formed semiconductor device can meet the designed dimensional requirements.

[0007] To solve the above problems, the present invention provides an optical proximity correction method, including: providing a target pattern; increasing the side length of the target pattern to form an initial pattern; correcting the initial pattern to obtain a corresponding first corrected pattern; forming an auxiliary pattern that surrounds the first corrected pattern; comparing the difference factor between the first corrected pattern and the auxiliary pattern; if the value of the difference factor is greater than a predetermined threshold, increasing the area of the target pattern corresponding to the first corrected pattern to form a corrected target pattern; performing a process correction on the first corrected pattern to obtain a corresponding process corrected pattern; repeating the above step of comparing the difference factor until the correction meets a predetermined number of times; and finally correcting the formed first corrected pattern and process corrected pattern to obtain a corrected pattern.

[0008] Optionally, finally correct the formed first corrected pattern and process corrected pattern to obtain a corrected pattern.

[0009] Optionally, the range of the predetermined threshold is 20% - 40%.

[0010] Optionally, the distance from each side of the corrected target pattern to the corresponding side of the target pattern is 0.25 nanometers - 2 nanometers.

[0011] Optionally, the distance from each side of the initial pattern to the corresponding side of the target pattern is 1 nanometer - 5 nanometers.

[0012] Optionally, the auxiliary pattern is the smallest pattern that surrounds the first corrected pattern.

[0013] Optionally, the step of obtaining the first corrected pattern includes: setting a plurality of sampling points on the target pattern; obtaining an initial exposure pattern corresponding to the initial pattern; comparing the position difference between the initial exposure pattern and the target pattern at the sampling points to obtain the edge position error value of the initial exposure pattern; obtaining the first ratio of the edge position error value of the initial exposure pattern to the set edge position error threshold, and when the first ratio is within a predetermined range, completing the correction of the initial pattern; when the first ratio is not within the predetermined range, adjusting the initial pattern and re-executing the above steps of obtaining the initial exposure pattern and comparing for the adjusted initial pattern until the first ratio is within the predetermined range.

[0014] Optionally, when the first ratio is not within the predetermined range, the way to adjust the initial pattern includes: adjusting the sides of the initial pattern.

[0015] Optionally, the predetermined range is between 1 and 2.

[0016] Optionally, the step of obtaining the process-corrected pattern includes: setting a plurality of sampling points on the corrected target pattern; obtaining a first exposure pattern corresponding to the first corrected pattern; comparing the position differences between the first exposure pattern and the corrected target pattern at the sampling points to obtain an edge position error value of the first exposure pattern; obtaining a second ratio of the edge position error value of the first exposure pattern to a set edge position error threshold, where the second ratio is within the predetermined range, completing the process correction of the first corrected pattern to obtain a corresponding process-corrected pattern; when the second ratio is not within the predetermined range, adjusting the first corrected pattern and re-executing the above steps of obtaining the first exposure pattern and comparing for the adjusted first corrected pattern until the second ratio is within the predetermined range, completing the process correction of the first corrected pattern to obtain a corresponding process-corrected pattern.

[0017] Optionally, the step of obtaining the corrected pattern includes: obtaining a process exposure pattern corresponding to the process-corrected pattern; comparing the position differences between the first exposure pattern and the target pattern at the sampling points, and at the same time comparing the position differences between the process exposure pattern and the corrected target pattern at the sampling points to respectively obtain an edge position error value of the first exposure pattern and an edge position error value of the process exposure pattern; respectively determining whether the edge position error values of the first exposure pattern and the process exposure pattern are greater than a set edge position error threshold. When the edge position error values of the first exposure pattern and the process exposure pattern are both less than or equal to the set edge position error threshold, completing the final correction of the first corrected pattern and the process-corrected pattern to obtain a corrected pattern; when the edge position error value of the first exposure pattern or the edge position error value of the process exposure pattern is greater than the set edge position error threshold, adjusting the first corrected pattern or the process-corrected pattern, and re-executing the above steps of obtaining the first exposure pattern, obtaining the process exposure pattern, and comparing for the adjusted first corrected pattern or process-corrected pattern until the edge position error values of the first exposure pattern and the process exposure pattern are both less than or equal to the set edge position error threshold, completing the final correction of the first corrected pattern and the process-corrected pattern to obtain a corrected pattern.

[0018] Optionally, the range of the predetermined number of times is from 1 to 3 times.

[0019] The present invention provides a method for manufacturing a photomask, comprising: providing a target pattern; increasing the side length of the target pattern to form an initial pattern; correcting the initial pattern to obtain a corresponding first corrected pattern; forming an auxiliary pattern that surrounds the first corrected pattern; comparing a difference factor between the first corrected pattern and the auxiliary pattern; if the value of the difference factor is greater than a predetermined threshold, increasing the area of the target pattern corresponding to the first corrected pattern to form a corrected target pattern; performing a process correction on the first corrected pattern to obtain a corresponding process-corrected pattern; repeating the step of comparing the difference factor until a predetermined number of corrections is satisfied; performing a final correction on the formed first corrected pattern and process-corrected pattern to obtain a corrected pattern; and transferring the obtained corrected pattern onto a photomask to form a mask pattern.

[0020] The present invention provides a patterning method, comprising: providing a target pattern; increasing the side length of the target pattern to form an initial pattern; correcting the initial pattern to obtain a corresponding first corrected pattern; forming an auxiliary pattern that surrounds the first corrected pattern; comparing a difference factor between the first corrected pattern and the auxiliary pattern; if the value of the difference factor is greater than a predetermined threshold, increasing the area of the target pattern corresponding to the first corrected pattern to form a corrected target pattern; performing a process correction on the first corrected pattern to obtain a corresponding process-corrected pattern; repeating the step of comparing the difference factor until a predetermined number of corrections is satisfied; performing a final correction on the formed first corrected pattern and process-corrected pattern to obtain a corrected pattern; transferring the obtained corrected pattern onto a photomask to form a mask pattern; and transferring the mask pattern onto a wafer to form a final pattern.

[0021] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0022] After forming the first corrected pattern, an auxiliary pattern is formed, and a difference factor between the first corrected pattern and the auxiliary pattern is compared. If the value of the difference factor is greater than a predetermined threshold, the area of the target pattern corresponding to the first corrected pattern is increased to form a corrected target pattern, and then a final correction is performed on the formed first corrected pattern and process-corrected pattern to obtain a corrected pattern. Since the target pattern is increased during the process of obtaining the corrected pattern, not only the area of the corrected pattern is increased but also the distortion that occurs after optical proximity correction of the pattern is reduced, making the process of transferring the pattern onto a wafer using a photomask easier. Thereby, the accuracy of pattern transfer can be ensured, and the formed semiconductor device can meet the designed dimensional requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figures 1 to 12 are schematic diagrams of each step in an embodiment of the optical proximity correction method of the present invention. Detailed implementation manners

[0024] The steps of the currently common optical proximity correction method include: providing a target pattern, inputting an initial pattern corresponding to the target pattern, performing optical proximity correction on the initial pattern to obtain a process correction pattern, exposing the process correction pattern to obtain an exposed pattern, comparing the exposed pattern with the target pattern, and when the exposed pattern meets the comparison condition, ending the correction to obtain a corrected pattern. Subsequently, the corrected pattern is transferred onto a photomask to form a mask pattern, and then the mask pattern is transferred onto a wafer to form a final pattern.

[0025] The inventor found that when obtaining the final pattern, due to the limitation of the size of the photomask, when the pattern is transferred onto the wafer, pattern loss occurs, resulting in the final pattern formed on the wafer surface not meeting the actual requirements.

[0026] The inventor's research found that after correcting the initial pattern to obtain a first corrected pattern, an auxiliary pattern surrounding the first corrected pattern is formed. At this time, the difference factor between the auxiliary pattern and the first corrected pattern is compared. When the difference factor is greater than a predetermined threshold, the area of the target pattern is increased, and the first corrected pattern is subjected to process correction to form a process correction pattern; then, final correction is performed on the first corrected pattern and the process correction pattern to obtain a corrected pattern. During the process of obtaining the corrected pattern, increasing the area of the target pattern causes the area of the corresponding corrected pattern to increase. Then, when the lithography pattern is transferred onto the wafer, since the area of the formed corrected pattern becomes larger, the process of transferring the pattern on the photomask onto the wafer becomes easier, ensuring that no pattern loss occurs during the lithography process, guaranteeing the accuracy of pattern transfer, and at the same time reducing the difficulty of lithography.

[0027] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of specific embodiments of the present invention will be given with reference to the accompanying drawings.

[0028] Figures 1 to 12 It is a schematic diagram of each step in an embodiment of the optical proximity correction method of the present invention.

[0029] First, refer to Figure 1 , and provide a target pattern 100.

[0030] The target pattern 100 is the target of optical proximity correction, that is, ideally, the pattern on the wafer is the same as the target pattern 100.

[0031] In this embodiment, the number of the target patterns 100 is taken as four as an example; in other embodiments, the number of the target patterns 100 can be many.

[0032] Refer to Figure 2 , and set a plurality of sampling points on the target pattern 100.

[0033] In this embodiment, taking one of the target graphics as an example, the setting of sampling points is shown.

[0034] The sampling points include A1 and A2 on side A, B1 and B2 on side B, sampling points C1 and C2 on side C, and D1 and D2 on side D.

[0035] In this embodiment, the sampling points are located on the sides of the target graphic 100; in other embodiments, the sampling points are located on the sides or corners of the target graphic 100.

[0036] The sampling points are used to compare the differences between the target graphic 100 and the initial graphic set subsequently, obtain the influence of optical proximity correction on the target graphic 100, and be used to obtain the edge position error for judging whether the optical proximity correction is completed.

[0037] Reference Figure 3 , increase the side length of the target graphic 100 to form the initial graphic 200.

[0038] The distance from each side of the initial graphic 200 to the corresponding side of the target graphic 100 is between 1 nanometer and 5 nanometers.

[0039] In this embodiment, taking one of the target graphics as an example, the setting of the initial graphic is shown.

[0040] In this embodiment, the distance from each side of the initial graphic 200 to the corresponding side of the target graphic 100 is 1.5 nanometers, that is, the size of d in the figure.

[0041] The initial graphic 200 is used to obtain the initial exposure graphic and make adjustments in subsequent optical proximity correction to obtain the influence of the optical proximity correction effect on the graphic, and perform optical proximity correction by modifying the initial graphic 200.

[0042] In this embodiment, the initial graphic 200 is inconsistent with the target graphic 100; in other embodiments, the initial graphic 200 may also be consistent with the target graphic 100.

[0043] In this embodiment, partial optical proximity correction is introduced into the initial graphic 200 to further improve the convergence speed of the optical proximity correction.

[0044] Reference Figure 4 , obtain the initial exposure graphic 300 corresponding to the initial graphic 200.

[0045] In this embodiment, the simulation method is used to obtain the initial exposure graphic 300 corresponding to the initial graphic 200.

[0046] In this embodiment, taking one of the initial patterns 200 as an example, the obtained exposed pattern 300 is shown.

[0047] In this embodiment, the initial exposed pattern 300 is obtained under standard process conditions without being restricted by the process window.

[0048] Refer to Figure 5 , compare the position differences between the initial exposed pattern 300 and the target pattern 100 at the sampling points, and obtain the edge position error value of the initial exposed pattern 300.

[0049] In this embodiment, for the edge position error of the sampling points set on the side of the target pattern 100, by comparing the position differences between the sampling points and the initial exposed pattern 300 in the direction perpendicular to the side, the corresponding edge position error of the sampling points is obtained.

[0050] In this embodiment, taking one of the target patterns 100 as an example, the position differences between the target pattern 100 and the initial exposed pattern 300 are shown, so as to obtain the corresponding edge position error.

[0051] Specifically, for the sampling point A1 set on the side A of the target pattern 100, at the sampling point A1, there is a first direction (x direction) of extension and a second direction (y direction) perpendicular to the first direction (x direction). The edge position error value at the sampling point A1 is the position error value EPE between the sampling point A1 and the initial exposed pattern 300 along the second direction (y direction). A1 .

[0052] Similarly, the position errors of A2, B1, B2, C1, C2, D1, and D2 are EPE A2 , EPE B1 , EPE B2 , EPE C1 , EPE C2 , EPE D1 , EPE D2 are obtained in the same way as the method for obtaining EPE A1 .

[0053] Refer to Figure 6 , and provide a flowchart for obtaining the first corrected pattern by correcting Figure 1 .

[0054] After executing step S50 and obtaining the ratio of the edge position error value of the initial exposed pattern 300 to the set edge position error threshold, the ratio obtained in this step is the first ratio. Then execute step S60 to determine whether the first ratio is within a predetermined range.

[0055] In this embodiment, the step of determining whether the first ratio is within a predetermined range includes: obtaining an average value of the first ratios as the average first ratio according to the first ratios of the edge position errors of each sampling point in the initial exposure pattern 300 to the set edge position error threshold. Therefore, in this embodiment, when performing step S60 to determine whether the first ratio is within the predetermined range, it is to determine whether the average value of the first ratios is within the predetermined range.

[0056] Continue to refer to Figure 6 , when it is determined that the first ratio is within the predetermined range, the optical correction is completed, and step S70 is performed to obtain the first corrected pattern.

[0057] When it is determined that the first ratio is not within the predetermined range, step S80 is performed to adjust the initial pattern 200 to reduce the edge position error, thereby reducing the first ratio to the predetermined edge position error to reduce the difference.

[0058] When it is determined that the first ratio is not within the predetermined range, the step of adjusting the initial pattern 200 includes: obtaining the positions of the sampling points corresponding to the first ratio not being within the predetermined range according to the first ratio of the edge position error to the set edge position error threshold, and adjusting the edges of the initial pattern 200 corresponding to the sampling points according to the positions of the sampling points to reduce the difference between the first ratio and the predetermined range.

[0059] In this embodiment, the predetermined range is between 1 and 2. For example, assuming the edge position error threshold is 1.5, the first ratios of the edge position errors of each sampling point in the initial exposure pattern 300 to the set edge position error threshold are between 1 and 2, that is, the edge position error values of each sampling point in the initial exposure pattern 300 being 3 nanometers or 2.5 nanometers both meet the requirements, and the first corrected pattern is obtained after the correction is completed.

[0060] Refer to Figure 7 , which shows Figure 1 After optical correction, the first corrected pattern 400 is obtained, and an auxiliary pattern 500 is formed around the first corrected pattern 400, and the auxiliary pattern 500 surrounds the first corrected pattern 400.

[0061] In this embodiment, the auxiliary pattern 500 is the smallest pattern surrounding the first corrected pattern 400.

[0062] In this embodiment, the purpose of forming the auxiliary pattern is to reduce pattern distortion and ensure the accuracy of pattern transfer. This is because after the initial pattern is corrected to obtain the first corrected pattern 400, some patterns in the first corrected pattern 400 exhibit severe distortion. Then, during subsequent optical correction, the distortion degree of these patterns increases, and it is very easy for them to be omitted during subsequent transfer to the wafer, or due to lithography conditions, severely distorted patterns cannot be transferred to the wafer, thereby reducing the accuracy of pattern transfer.

[0063] Reference Figure 8 , provides a flowchart for obtaining a corrected target pattern and an acquired process corrected pattern by comparing difference factors for Figure 7 .

[0064] Figure 8 In Figure 6 , S20, S30, S40, and S50 in

[0065] are the omitted representations of S20, S30, S40, and S50 in Figure 6 .

[0066] After step S90 is executed to form the auxiliary pattern 500, step S91 is executed to obtain the difference factor between the first corrected pattern 400 and the auxiliary pattern 500, and then step S100 is executed to determine whether the value of the difference factor is less than or equal to a predetermined threshold.

[0067] In this embodiment, the step of determining whether the value of the difference factor is less than or equal to a predetermined threshold includes: calculating the area of the auxiliary pattern 500 as S 1 , the area of the first corrected pattern 400 as S 0 , and the difference factor = (S 1 - S 0 ) / S 1 * 100%.

[0068] In this embodiment, the range of the predetermined threshold is 20% - 40%.

[0069] Continuing to refer to Figure 8 and Figure 6 , when it is determined that the value of the difference factor is less than or equal to the predetermined threshold, step S300 is executed to keep the first corrected pattern unchanged, that is, the first corrected pattern 400 is obtained.

[0070] When it is determined that the value of the difference factor is greater than the predetermined threshold, step S200 is executed to adjust the target pattern 100 to obtain the corrected target pattern.

[0071] In this embodiment, the distance from each side of the corrected target pattern to each corresponding side of the target pattern 100 is 0.25 nanometers to 2 nanometers.

[0072] Execute step S20 to set a plurality of sampling points on the corrected target pattern;

[0073] In this embodiment, a plurality of sampling points are set on the sides of the corrected target pattern.

[0074] Specific sampling points include a1 and a2 on side a, b1 and b2 on side b, sampling points c1 and c2 on side c, and d1 and d2 on side d.

[0075] Execute step S30, and the first corrected pattern 400 at this time is the initial pattern;

[0076] Execute step S40 to obtain the first exposure pattern corresponding to the first corrected pattern 400;

[0077] Compare the position differences between the first exposure pattern and the corrected target pattern at the sampling points to obtain the edge position error value of the first exposure pattern.

[0078] In this embodiment, the process of obtaining the edge position error value of the first exposure pattern is the same as the process of obtaining the edge position error value of the initial exposure pattern, and will not be elaborated here.

[0079] After executing step S50 to obtain the second ratio of the edge position error value of the first exposure pattern to the set edge position error threshold, execute step S60 to determine whether the second ratio is within the predetermined range.

[0080] In this embodiment, the step of determining whether the second ratio is within the predetermined range includes: obtaining the average value of the second ratios as the average second ratio according to the second ratios of the edge position errors of the respective sampling points in the first exposure pattern to the set edge position error threshold. Therefore, in this embodiment, when executing step S60 to determine whether the second ratio is within the predetermined range, it is to determine whether the average value of the second ratios is within the predetermined range.

[0081] Continue to refer to Figure 8 and Figure 6 , when it is determined that the second ratio is within the predetermined range, execute step S300 to obtain the corresponding process corrected pattern;

[0082] When it is determined that the second ratio is not within the predetermined range, execute step S80 to adjust the first corrected pattern. At this time, the first corrected pattern is equivalent to the initial pattern to reduce the edge position error, thereby reducing the second ratio of the edge position error to the predetermined value to reduce the difference.

[0083] When it is determined that the second ratio is not within the predetermined range, the steps of adjusting the first corrected pattern 400 include: obtaining the positions of the sampling points corresponding to the second ratio not being within the predetermined range according to the second ratio of the edge position error and the set edge position error threshold, and adjusting the edges corresponding to the sampling points in the first corrected pattern according to the positions of the sampling points to reduce the difference between the second ratio and the predetermined range.

[0084] In this embodiment, it is judged whether the second ratio is within a predetermined range, and this predetermined range is the same as the predetermined range for judging whether the first ratio is within the predetermined range.

[0085] In this embodiment, the step of comparing the difference factors is performed once; in other embodiments, it can be performed 2 times, 3 times, etc.

[0086] Specifically, when the step of comparing the difference factors is performed 2 times, refer to Figure 9 and Figure 6 .

[0087] Figure 9 where S20, S30, S40, S50 in Figure 6 are the abbreviated representations of steps S20, S30, S40, S50 in

[0088] When the process of judging whether the first ratio or the second ratio is within the predetermined range is the same as that in Figure 6 the same.

[0089] After executing step S90 to form the auxiliary pattern 500, execute step S91, obtain the difference factor between the first corrected pattern 400 and the auxiliary pattern 500, and then execute step S100 to judge whether the value of the difference factor is less than or equal to the predetermined threshold; when it is judged that the value of the difference factor is less than or equal to the predetermined threshold, execute step S300 to keep the first corrected pattern unchanged, that is, obtain the first corrected pattern 400; when it is judged that the value of the difference factor is greater than the predetermined threshold, execute step S200 to adjust the target pattern 100, obtain the corrected target pattern, and then execute steps S10 to S60 (refer to Figure 6 ), when it is judged that the second ratio is within the predetermined range, execute step S90, form an auxiliary pattern around the process corrected pattern obtained for the first time, then execute step S91, obtain the difference factor between the process corrected pattern obtained for the first time and the auxiliary pattern, and then execute step S100 to judge whether the value of the difference factor is less than or equal to the predetermined threshold. When it is judged that the value of the difference factor is less than or equal to the predetermined threshold, execute step S300 to obtain the corresponding process corrected pattern; when it is judged that the value of the difference factor is greater than the predetermined threshold, re-execute step S200, steps S10 to step S60 (refer to Figure 6After the second ratio is within the predetermined range, step S300 is executed to obtain the corresponding process correction pattern.

[0090] In this embodiment, the step of comparing the difference factors is repeated, and the predetermined number of corrections is between 1 and 3. When the predetermined number of corrections is less than 1, that is, no correction is performed. Then, after obtaining the first correction pattern, the pattern with severe distortion will not be detected. When continuing the subsequent correction, the distortion degree of the pattern will increase. Then, when transferring the pattern to the wafer during the lithography process, there will be missing patterns or restrictions due to lithography conditions, making it difficult to transfer the pattern to the wafer, increasing the difficulty of the lithography process. When the predetermined number of corrections is greater than 3, the number of corrections is too many at this time. Because the area of the target pattern needs to be increased during the correction process, the larger the target pattern becomes, the smaller the distance from the surrounding patterns, which may cause bridging with the surrounding target patterns and the corresponding mask cannot be realized.

[0091] Reference Figure 10 , according to the comparison of the difference factors, the final target pattern obtained includes the target pattern 100 and the corrected target pattern 110.

[0092] In this embodiment, a plurality of sampling points (not shown in the figure) are set on the target pattern 100, which are the same as the sampling points when obtaining the first correction pattern 400.

[0093] In this embodiment, a plurality of sampling points (not shown in the figure) are set on the corrected target pattern 110, which are the same as the sampling points when obtaining the process correction pattern.

[0094] Obtain the first exposure pattern for the first correction pattern, and obtain the process exposure pattern for the process correction pattern.

[0095] Specifically, the first exposure pattern and the process exposure pattern are obtained by simulation.

[0096] In this embodiment, optical proximity correction model is used for lithography simulation imaging. According to the first correction pattern and the process correction pattern, the manufacturing of the mask is simulated, and steps such as exposure, development, and etching under standard process conditions are obtained based on the mask to obtain the standard exposure pattern.

[0097] In this embodiment, the simulation method is to obtain the exposure pattern; in other embodiments, the exposure pattern can also be obtained by actual exposure.

[0098] Compare the position difference between the first exposure pattern and the target pattern 100 at the sampling points to obtain the edge position error value of the first exposure pattern; compare the position difference between the process exposure pattern and the corrected target pattern 110 at the sampling points to obtain the edge position error value of the process exposure pattern.

[0099] The method for specifically obtaining the edge position error value of the first exposure pattern and the edge position error value of the process exposure pattern is the same as that for obtaining the edge position error value of the initial exposure pattern 300, and will not be elaborated here.

[0100] Reference Figure 11 , provides a flowchart for performing a final correction on Figure 10 to obtain a corrected pattern.

[0101] After obtaining the exposure pattern in step S310, in step S400, after respectively obtaining the edge position error of the first exposure pattern and the edge position error of the process exposure pattern, step S500 is executed to respectively determine whether the edge position error value of the first exposure pattern and the edge position error value of the process exposure pattern are greater than a set edge position error threshold.

[0102] In this embodiment, the step of respectively determining whether the edge position error value of the first exposure pattern and the edge position error value of the process exposure pattern are greater than a set edge position error threshold includes: obtaining the average value of the edge position error values of all sampling points in the first exposure pattern as the average edge position error average value of the first exposure pattern; obtaining the average value of the edge position error values of all sampling points in the process exposure pattern as the average edge position error average value of the process exposure pattern. Therefore, in this embodiment, in step S500, it is determined whether the average value of the average edge position error of the first exposure pattern and the average value of the edge position error value of the process exposure pattern are greater than a set edge position error threshold.

[0103] Continue to refer to Figure 11 , when the edge position error value of the first exposure pattern and the process exposure pattern is less than or equal to the set edge position error threshold, the final correction of the first corrected pattern and the process corrected pattern is completed, and step S600 is executed to obtain the corrected pattern.

[0104] Specifically, when it is determined that the edge position error value of the first exposure pattern is less than or equal to the set edge position error threshold and the edge position error value of the process exposure pattern is less than or equal to the set edge position error threshold, the optical correction is completed to obtain the corrected pattern.

[0105] When it is determined that the edge position error value of the first exposure pattern or the edge position error value of the process exposure pattern is greater than the set edge position error threshold, step S700 is executed to adjust the first correction pattern or the process correction pattern to reduce the difference between the edge position error and the set edge position error threshold.

[0106] In this embodiment, the step of adjusting the first correction pattern or the process correction pattern includes: obtaining the positions of the sampling points corresponding to the edge position error values greater than the set edge position error threshold according to the difference between the edge position errors of different sampling points and the set edge position error threshold; and adjusting the sides corresponding to the sampling points in the first correction pattern or the process correction pattern according to the positions of the sampling points greater than the set edge position error threshold to reduce the difference between the edge position error and the threshold.

[0107] In this embodiment, the step of adjusting the side corresponding to the sampling point includes: when the sampling point is set on the side of the pattern, adjusting the side where the sampling point is located; when the sampling point is set at a corner, adjusting the side closest to the sampling point.

[0108] Continue to refer to Figure 11 and in combination with reference to Figure 12 , execute step S700 to obtain an adjusted first correction pattern after adjusting the first correction pattern 400, or obtain an adjusted process correction pattern after adjusting the process correction pattern, and re-execute step S310 to obtain an exposure pattern, step S400 to obtain an edge position error value, and step S500 to compare the edge position error value with the set edge position error value threshold for the adjusted first correction pattern or process correction pattern until the edge position error values of the first exposure pattern and the process exposure pattern are both less than or equal to the set edge position error threshold, then the optical proximity correction is completed and the correction pattern 600 is obtained.

[0109] Figure 12 Shows Figure 10 the correction pattern 600 obtained after the optical proximity correction of the shown target pattern is completed.

[0110] The present invention also provides a method for manufacturing a photomask, transferring the correction pattern 600 obtained by using the above optical proximity correction method onto the photomask to form a mask pattern.

[0111] The present invention also provides a patterning method, transferring the obtained mask pattern onto a wafer to form a final pattern.

[0112] Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims of the present invention.

Claims

1. An optical proximity correction method, characterized in that: include: Provide target graphics; Increasing the side length of the target figure to form an initial figure; Correcting the initial graph to obtain a corresponding first corrected graph; forming an auxiliary pattern, wherein the auxiliary pattern surrounds the first correction pattern; Compare the difference factor between the first correction pattern and the auxiliary pattern, the area of ​​the auxiliary pattern is S1, the area of ​​the first correction pattern is S0, and the difference factor = (S1-S0) / S1*100%; If the difference factor is less than or equal to a predetermined threshold, the first correction graph remains unchanged; If the value of the difference factor is greater than a predetermined threshold, the area of ​​the target pattern corresponding to the first correction pattern is increased to form a corrected target pattern, and the first correction pattern is subjected to process correction to obtain a corresponding process correction pattern, specifically: obtaining a first exposure pattern corresponding to the first correction pattern; comparing the position difference between the first exposure pattern and the corrected target pattern at the sampling point to obtain an edge position error value of the first exposure pattern; when the ratio of the edge position error value of the first exposure pattern to the set edge position error threshold is within a predetermined range, obtaining a corresponding process correction pattern; Repeat the above steps of comparing the difference factors until the correction meets the predetermined number of times; Performing final correction on the first correction pattern and the process correction pattern respectively obtained by comparing the difference factors to obtain the correction pattern, specifically: obtaining a first exposure pattern of the first correction pattern and obtaining a process exposure pattern of the process correction pattern; respectively obtaining an edge position error of the first exposure pattern and an edge position error of the process exposure pattern; When the edge position error value between the first exposure pattern and the process exposure pattern is less than or equal to a set edge position error threshold, the corrected pattern is obtained.

2. The optical proximity correction method according to claim 1, characterized in that: The predetermined threshold value ranges from 20% to 40%.

3. The optical proximity correction method according to claim 1, characterized in that: The distance between each edge of the modified target pattern and each edge corresponding to the target pattern is 0.25 nanometers to 2 nanometers.

4. The optical proximity correction method according to claim 1, wherein: The distance between each edge of the initial pattern and each corresponding edge of the target pattern is 1 nanometer to 5 nanometers.

5. The optical proximity correction method according to claim 1, wherein: The auxiliary figure is a minimum figure surrounding the first correction figure.

6. The optical proximity correction method according to claim 1, wherein: The step of obtaining the first corrected graph comprises: Setting a plurality of sampling points on the target graph; Acquire an initial exposure pattern corresponding to the initial pattern; Comparing the position difference between the initial exposure pattern and the target pattern at the sampling point, and obtaining the edge position error value of the initial exposure pattern; Obtaining a first ratio of an edge position error value of the initial exposure pattern to a set edge position error threshold, and completing correction of the initial pattern when the first ratio is within a predetermined range; When the first ratio is not within the predetermined range, the initial pattern is adjusted, and the steps of obtaining the initial exposure pattern and comparing are performed again on the adjusted initial pattern until the first ratio is within the predetermined range.

7. The optical proximity correction method according to claim 6, characterized in that: When the first ratio is not within a predetermined range, the method of adjusting the initial figure includes: adjusting a side of the initial figure.

8. The optical proximity correction method according to claim 6, wherein: The predetermined range is between 1 and 2.

9. The optical proximity correction method according to claim 8, characterized in that: The step of acquiring the process correction pattern further includes: before acquiring the first exposure pattern corresponding to the first correction pattern, setting a plurality of sampling points on the correction target pattern; The method for obtaining a ratio of the edge position error value of the first exposure pattern to a set edge position error threshold value within a predetermined range includes: obtaining a second ratio of the edge position error value of the first exposure pattern to the set edge position error threshold value, the second ratio being within the predetermined range, completing process correction of the first correction pattern, and obtaining a corresponding process correction pattern; When the second ratio is not within the predetermined range, the first correction pattern is adjusted, and the above-mentioned steps of obtaining the first exposure pattern and comparing are re-executed on the adjusted first correction pattern until the second ratio is within the predetermined range, and the process correction of the first correction pattern is completed to obtain the corresponding process correction pattern.

10. The optical proximity correction method according to claim 9, characterized in that: The step of obtaining the modified graph further includes: The method of respectively obtaining the edge position error value of the first exposure pattern and the edge position error value of the process exposure pattern comprises: comparing the position difference between the first exposure pattern and the target pattern at the sampling point, and comparing the position difference between the process exposure pattern and the corrected target pattern at the sampling point; When the edge position error value of the first exposure pattern or the edge position error value of the process exposure pattern is greater than a set edge position error threshold, the first correction pattern or the process correction pattern is adjusted, and the above-mentioned steps of obtaining the first exposure pattern, obtaining the process exposure pattern and comparing are re-executed on the adjusted first correction pattern or the process correction pattern until the edge position error value of the first exposure pattern and the edge position error value of the process exposure pattern are both less than or equal to the set edge position error threshold, and the final correction of the first correction pattern and the process correction pattern is completed to obtain the correction pattern.

11. The optical proximity correction method according to claim 1, wherein: The predetermined number of times ranges from 1 to 3 times.

12. A method for making a photomask, characterized in that: include: Provide target graphics; Increasing the side length of the target figure to form an initial figure; Correcting the initial graph to obtain a corresponding first corrected graph; forming an auxiliary pattern, wherein the auxiliary pattern surrounds the first correction pattern; Compare the difference factor between the first correction pattern and the auxiliary pattern, the area of ​​the auxiliary pattern is S1, the area of ​​the first correction pattern is S0, and the difference factor = (S1-S0) / S1*100%; If the difference factor is less than or equal to a predetermined threshold, the first correction graph remains unchanged; If the value of the difference factor is greater than a predetermined threshold, the area of ​​the target pattern corresponding to the first correction pattern is increased to form a corrected target pattern, and the first correction pattern is subjected to process correction to obtain a corresponding process correction pattern, specifically: obtaining a first exposure pattern corresponding to the first correction pattern; comparing the position difference between the first exposure pattern and the corrected target pattern at the sampling point to obtain an edge position error value of the first exposure pattern; when the ratio of the edge position error value of the first exposure pattern to the set edge position error threshold is within a predetermined range, obtaining a corresponding process correction pattern; Repeat the above steps of comparing the difference factors until the correction meets the predetermined number of times; Performing final correction on the first correction pattern and the process correction pattern respectively obtained by comparing the difference factors to obtain the correction pattern, specifically: obtaining a first exposure pattern of the first correction pattern and obtaining a process exposure pattern of the process correction pattern; respectively obtaining an edge position error of the first exposure pattern and an edge position error of the process exposure pattern; When the edge position error value between the first exposure pattern and the process exposure pattern is less than or equal to a set edge position error threshold, obtaining the corrected pattern; The obtained correction pattern is transferred to the photomask to form a mask pattern.

13. A graphical method, characterized in that: include: Provide target graphics; Increasing the side length of the target figure to form an initial figure; Correcting the initial graph to obtain a corresponding first corrected graph; forming an auxiliary pattern, wherein the auxiliary pattern surrounds the first correction pattern; Compare the difference factor between the first correction pattern and the auxiliary pattern, the area of ​​the auxiliary pattern is S1, the area of ​​the first correction pattern is S0, and the difference factor = (S1-S0) / S1*100%; If the difference factor is less than or equal to a predetermined threshold, the first correction graph remains unchanged; If the value of the difference factor is greater than a predetermined threshold, the area of ​​the target pattern corresponding to the first correction pattern is increased to form a corrected target pattern, and the first correction pattern is subjected to process correction to obtain a corresponding process correction pattern, specifically: obtaining a first exposure pattern corresponding to the first correction pattern; comparing the position difference between the first exposure pattern and the corrected target pattern at the sampling point to obtain an edge position error value of the first exposure pattern; when the ratio of the edge position error value of the first exposure pattern to the set edge position error threshold is within a predetermined range, obtaining a corresponding process correction pattern; Repeat the above steps of comparing the difference factors until the correction meets the predetermined number of times; Performing final correction on the first correction pattern and the process correction pattern respectively obtained by comparing the difference factors to obtain the correction pattern, specifically: obtaining a first exposure pattern of the first correction pattern and obtaining a process exposure pattern of the process correction pattern; respectively obtaining an edge position error of the first exposure pattern and an edge position error of the process exposure pattern; When the edge position error value between the first exposure pattern and the process exposure pattern is less than or equal to a set edge position error threshold, obtaining the corrected pattern; transferring the acquired correction pattern to a photomask to form a mask pattern; The mask pattern is transferred to the wafer to form the final pattern.

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