Method for evaluating photomask manufacturing precision, photomask manufacturing method, photomask, and AG cover plate

Abstract

The present invention discloses a method for evaluating the manufacturing precision of a photomask, a method for manufacturing a photomask, a photomask, and an AG cover plate, which relates to the technical field of photomask manufacturing. The evaluation method includes the following steps: providing a preset pattern for forming a through hole on the photomask; providing a processing precision; simulating the area of the actual pattern when forming the through hole according to the processing precision; taking the difference between the area of the preset pattern and the area of the actual pattern and taking the absolute value; dividing the absolute value by the area of the preset pattern to obtain an actual distortion degree; and evaluating the manufacturing precision of the photomask according to the actual distortion degree. The present invention solves the technical problem that in the manufacturing process of the photomask, it is not possible to well match the processing precision.

Description

Technical Field

[0001] The present invention relates to the technical field of photomask manufacturing, and particularly to a method for evaluating the manufacturing precision of a photomask, a method for manufacturing a photomask, a photomask, and an AG cover plate. Background Art

[0002] During the manufacturing process of the photomask required for the processing of the AG cover plate in the existing lithography process, when the processing precision is low, local patch unevenness will occur. When the processing precision is too high, although the problem of local patch unevenness can be solved, it will inevitably cause waste of costs. Currently, during the manufacturing process of the photomask, there is a lack of a method that can effectively evaluate the manufacturing precision of the photomask, resulting in the problem that the processing precision cannot be well matched during the manufacturing process of the photomask. Summary of the Invention

[0003] In view of this, the present invention provides a method for evaluating the manufacturing precision of a photomask, a method for manufacturing a photomask, a photomask, and an AG cover plate, which are used to solve the technical problem that the processing precision cannot be well matched during the manufacturing process of the photomask.

[0004] To solve the above technical problem, the first technical solution adopted by the present invention is as follows:

[0005] A method for evaluating the manufacturing precision of a photomask, the evaluation method comprising the following steps:

[0006] Providing a preset pattern for forming through holes on the photomask;

[0007] Providing a processing precision;

[0008] Simulating the area of the actual pattern when forming the through holes according to the processing precision;

[0009] Taking the difference between the area of the preset pattern and the area of the actual pattern, and taking the absolute value;

[0010] Dividing the absolute value by the area of the preset pattern to obtain the actual distortion degree;

[0011] Evaluating the manufacturing precision of the photomask according to the actual distortion degree.

[0012] In some embodiments of the method for evaluating the manufacturing precision of the photomask, the step of simulating the actual pattern when forming the through holes according to the processing precision comprises the following steps:

[0013] Drawing a processed micro-pattern according to the processing precision;

[0014] Fully filling a plurality of the processed micro-patterns in the preset pattern to form an actual pattern;

[0015] Reading out the number of the processed micro-patterns in the preset pattern to know the area of the actual pattern.

[0016] In some embodiments of the photomask manufacturing precision evaluation method, the step of reading the number of processed micro-graphs within the preset graph includes the following steps:

[0017] Perform area segmentation on the processed micro-graphs that are not completely within the preset graph to obtain the in-circle area within the preset graph;

[0018] Calculate the ratio of the in-circle area to the area of the processed micro-graph to obtain the actual area ratio;

[0019] Set the minimum value of the area ratio;

[0020] Compare the actual area ratio with the minimum value of the area ratio to determine the effectiveness of the processed micro-graphs that are not completely within the preset graph.

[0021] In some embodiments of the photomask manufacturing precision evaluation method, the minimum value of the area ratio is not less than 50%.

[0022] In some embodiments of the photomask manufacturing precision evaluation method, the step of evaluating the manufacturing precision of the photomask according to the actual distortion degree includes the following steps:

[0023] Provide a preset distortion degree;

[0024] Compare the actual distortion degree with the preset distortion degree to evaluate the manufacturing precision of the photomask.

[0025] In some embodiments of the photomask manufacturing precision evaluation method, the preset distortion degree is not higher than 2%.

[0026] To solve the above technical problems, the second technical solution adopted by the present invention is:

[0027] A photomask manufacturing method, the photomask manufacturing method includes the following steps:

[0028] Provide a substrate;

[0029] Form a chromium film on the substrate;

[0030] Provide a preset graph;

[0031] Provide a preset distortion degree;

[0032] Determine the range of processing precision according to the preset graph and the preset distortion degree;

[0033] Select a laser according to the range of processing precision;

[0034] Process the chromium film with the laser to form through holes in the chromium film, thereby manufacturing a photomask.

[0035] In some embodiments of the photomask manufacturing method, the preset distortion degree is not higher than 2%.

[0036] To solve the above technical problems, the third technical solution adopted by the present invention is:

[0037] A photomask is prepared by using the photomask manufacturing method in the above embodiments.

[0038] To solve the above technical problems, the fourth technical solution adopted by the present invention is:

[0039] An AG cover plate is lithographed based on the photomask in the above embodiments.

[0040] In some embodiments of the photomask manufacturing precision evaluation method,

[0041] Implementing the embodiments of the present invention will at least have the following beneficial effects:

[0042] The above photomask manufacturing precision evaluation method has the technical effect of evaluating the manufacturing precision of the photomask. Specifically, the photomask manufacturing precision evaluation method defines the distortion degree. First, the area difference between the actual pattern obtained by simulation and the preset pattern is calculated and the absolute value is taken. Then, the absolute value is divided by the area of the preset pattern to obtain the actual distortion degree. Finally, the manufacturing precision of the photomask can be evaluated according to the actual distortion degree. Through the evaluation method of the present invention, the manufacturing precision of the photomask can be evaluated, and then it is convenient to match the appropriate processing precision during the manufacturing process of the photomask, thus solving the technical problem that the processing precision cannot be well matched during the manufacturing process of the photomask.

[0043] The above photomask manufacturing method has the technical effect of selecting the appropriate processing precision. Specifically, the step of the photomask manufacturing method adds a preset distortion degree, and the determination of the processing precision range is based on the preset pattern and the preset distortion degree. Therefore, the photomask prepared by this method in the above embodiments can solve the problems of uneven local patches and cost waste simultaneously when manufacturing the AG cover plate. Description of the Drawings

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0045] Figure 1 It is a flowchart of the photomask manufacturing precision evaluation method in an embodiment;

[0046] Figure 2Flow chart of a photomask manufacturing method in an embodiment;

[0047] Figure 3 Schematic structural diagram of a photomask in an embodiment;

[0048] Figure 4 For Figure 3 Cross-sectional view of the shown photomask;

[0049] Figure 5 Schematic diagram of a 3um aperture circle and different processing precisions;

[0050] Figure 6 Schematic diagram of a 4um aperture circle and different processing precisions;

[0051] Figure 7 Schematic diagram of a 5um aperture circle and different processing precisions;

[0052] Figure 8 Schematic diagram of a 6um aperture circle and different processing precisions;

[0053] Figure 9 Schematic diagram of a 7um aperture circle and different processing precisions;

[0054] Figure 10 Schematic diagram of an 8um aperture circle and different processing precisions;

[0055] Figure 11 Schematic diagram of a 9um aperture circle and different processing precisions;

[0056] Figure 12 Schematic diagram of a 10um aperture circle and different processing precisions;

[0057] Figure 13 For the combined Figures 5 - 12 Broken line relationship diagram of distortion, processing precision and circular aperture.

[0058] Wherein: 1. Photomask; 11. Substrate; 12. Chromium film; 13. Through hole. Detailed implementation mode

[0059] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many other different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure content of the present invention more thorough and comprehensive.

[0060] It should be noted that when an element is referred to as "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0062] As Figure 1 shown, in an embodiment of a method for evaluating the manufacturing accuracy of a photomask, the evaluation method includes the following steps:

[0063] S1. Provide a preset pattern for forming a through hole 13 on the photomask 1.

[0064] S2. Provide the processing accuracy.

[0065] S3. Simulate according to the processing accuracy to obtain the area of the actual pattern when forming the through hole 13.

[0066] S4. Subtract the area of the preset pattern from the area of the actual pattern and take the absolute value.

[0067] S5. Divide the absolute value by the area of the preset pattern to obtain the actual distortion degree.

[0068] S6. Evaluate the manufacturing accuracy of the photomask 1 according to the actual distortion degree.

[0069] In this embodiment, the method for evaluating the manufacturing accuracy of a photomask defines the distortion degree. First, find the area difference between the actual pattern obtained by simulation and the preset pattern and take the absolute value, then divide the absolute value by the area of the preset pattern, that is, obtain the actual distortion degree. Finally, evaluate the manufacturing accuracy of the photomask 1 according to the actual distortion degree. Through the evaluation method of the present invention, it can be used to evaluate the manufacturing accuracy of the photomask 1, and then it is convenient to match the appropriate processing accuracy during the manufacturing process of the photomask 1, thus solving the technical problem that the processing accuracy cannot be well matched during the manufacturing process of the photomask 1.

[0070] The process of obtaining the actual distortion degree in the above embodiment can be expressed by the following formula:

[0071]

[0072] Wherein, Dis is the distortion degree, A1 is the area of the preset pattern, A2 is the area of the actual pattern, and abs is the function expression for taking the absolute value.

[0073] In an embodiment of a method for evaluating the manufacturing precision of a photomask, the steps for obtaining the actual pattern when forming the via hole 13 according to the simulation of the processing precision are as follows:

[0074] S31. Draw the processed micro-pattern according to the processing precision.

[0075] S32. Fully fill a plurality of processed micro-patterns into the preset pattern to form the actual pattern.

[0076] S33. Read out the number of processed micro-patterns in the preset pattern to obtain the area of the actual pattern.

[0077] In this embodiment, a method for obtaining the area of the actual pattern is given. Specifically, a two-dimensional plane can be constructed through simulation, then the preset pattern is placed into the two-dimensional plane, and then the processed micro-patterns are fully filled into the preset pattern, so that the actual pattern during actual processing can be simulated. Based on the simulation, it is also convenient to read out the number of processed micro-patterns. Since the area of each processed micro-pattern is constant, the area of the actual pattern can be obtained.

[0078] It should be noted that during the processing of the preset pattern, it is all treated as a mosaic polygon. Therefore, the processed micro-pattern can also be understood as the mosaic, and the pixel size of the mosaic is the resolution size. Usually, the manufacturing resolution of the mosaic is in the order of sub-microns to microns, that is, 0.1um - Xum. In some non-rectangular and non-square preset patterns, the smaller the pixel size of the mosaic, the higher the corresponding processing precision, and the more approximate the processed actual pattern is to the preset pattern. Taking the preset pattern as a circle as an example, the higher the processing precision, the higher the reduction degree of the circle, but the higher the manufacturing cost. On the contrary, the lower the processing precision, the greater the processing deformation of the circle.

[0079] In an embodiment of a method for evaluating the manufacturing precision of a photomask, the steps for reading out the number of processed micro-patterns in the preset pattern are as follows:

[0080] S331. Divide the area of the processed micro-pattern that is not completely located within the preset pattern to obtain the area within the circle located within the preset pattern.

[0081] S332. Divide the area within the circle by the area of the processed micro-pattern to obtain the actual area ratio.

[0082] S333. Set the minimum value of the area ratio.

[0083] S334. Compare the actual area ratio with the minimum value of the area ratio to determine the effectiveness of the processed micro-pattern that is not completely located within the preset pattern.

[0084] Based on different processing precisions, the sizes of the processed micro-graphics are different. When different processed micro-graphics are fully filled into the preset graphics, there will be a situation where some of the processed micro-graphics located in the outer circle have part of their area within the preset graphics and another part outside the preset graphics. In this regard, in this embodiment, a specific determination method is given. First, calculate the actual area ratio of each processed micro-graphic that appears in the above situation separately to determine the proportion of the area within the circle, and then compare the actual area ratio with the lowest value of the set area ratio. The processed micro-graphic with an actual area ratio higher than the lowest value of the area ratio is valid, otherwise it is invalid.

[0085] It should be noted that when a processed micro-graphic that is not completely within the preset graphics is determined to be valid, the calculated area is the entire area of the processed micro-graphic.

[0086] Preferably, the lowest value of the area ratio is not less than 50%, and specifically, it can be 50%, 60%, 70%, 80%, or 90%. Taking 50% as an example, if more than half of the processed micro-graphic is within the preset graphics, it is considered valid.

[0087] In an embodiment of a method for evaluating the manufacturing precision of a photomask, evaluating the manufacturing precision of photomask 1 according to the actual distortion includes the following steps:

[0088] S61. Provide a preset distortion.

[0089] S62. Compare the actual distortion with the preset distortion to evaluate the manufacturing precision of photomask 1.

[0090] Combined with the previous embodiments and this embodiment, it can be understood that the lower the actual distortion, the higher the processing precision, that is, the higher the reduction degree of the actual graphics to the preset graphics. And in this embodiment, by giving a preset distortion, the manufacturing precision of photomask 1 can be further judged, and it can also be used to judge whether the selected actual processing precision is matched. By comparing the actual distortion obtained by the method given in the previous embodiments with the preset distortion, if the actual distortion is higher than the preset distortion, it means that using this processing precision to process the preset graphics cannot meet the required preset distortion, so as to facilitate the staff to evaluate the processing precision.

[0091] Combined with the above embodiments, the above evaluation method can be used to evaluate photomask 1 used in forming the AG cover plate in the lithography process. The specific size of the preset distortion can be given based on the actual effect of obtaining the AG cover plate. By comparing the actual distortion with the preset distortion, it can be evaluated whether photomask 1 is suitable for preparing the AG cover plate. And when the obtained photomask 1 is used in lithography to obtain the AG cover plate, it can avoid the phenomenon of uneven local patches on the AG cover plate and meet the appearance requirements of the AG cover plate.

[0092] Preferably, the preset distortion degree is not higher than 2%. Specifically, the preset distortion degree can be 0.5%, 1.0%, 1.5% and 2.0%. By limiting the preset distortion degree to below 2%, the obtained photomask 1 has a good effect and better appearance uniformity when manufacturing the AG cover plate.

[0093] The present invention also relates to a method for manufacturing a photomask, as Figure 2 shown, the method for manufacturing a photomask includes the following steps:

[0094] S101. Provide a substrate 11.

[0095] S102. Form a chromium film 12 on the substrate 11.

[0096] S103. Provide a preset pattern.

[0097] S104. Provide a preset distortion degree.

[0098] S105. Determine the range of processing accuracy according to the preset pattern and the preset distortion degree.

[0099] S106. Select a laser according to the range of processing accuracy.

[0100] S107. Process the chromium film 12 by laser to form a through hole 13 on the chromium film 12, thereby obtaining the photomask 1.

[0101] In this embodiment, the step of providing a preset distortion degree is added to the steps of the method for manufacturing a photomask, and the determination of the range of processing accuracy is based on both the preset pattern and the preset distortion degree. The obtained photomask 1 by this method, due to the provision of the preset distortion degree, can conveniently select a suitable processing accuracy, so that the actual pattern obtained is closer to the preset pattern, and the error of the through hole 13 can also be within a reasonable range. Therefore, when manufacturing the AG cover plate, the problems of uneven local patches and cost waste can be solved simultaneously.

[0102] It should be noted that by limiting the preset distortion degree, it is not equivalent to directly limiting the processing accuracy, and the size of the preset pattern also needs to be combined. In a preferred embodiment of the method for manufacturing a photomask, specifically, the preset distortion degree can be limited to not higher than 2%. Taking the preset distortion degree of 2% as an example, and taking the preset pattern as a circle as an example, combined with Figures 5 - 12 and Figure 13 shown, Figures 5 - 12 comparison diagrams of the circular aperture with a diameter from 3um to 10um and the actual pattern and the preset pattern of the corresponding processing accuracy from 0.1um to 1um are respectively given, Figure 13 which is combined with Figures 5 - 12The broken line relationship diagram of the distortion degree, processing accuracy, and circular aperture. When the circular aperture is 7um - 10um, if the distortion degree is not greater than 2%, the required processing accuracy is less than 0.4um. When the circular aperture is greater than or equal to 5um and less than 7um, the required processing accuracy is less than 0.3um. And when the circular aperture is greater than or equal to 3um and less than 5um, the processing accuracy should be less than 0.1um. It can be seen that for different sizes of the preset pattern, the required processing accuracy needs to be reselected and adapted to balance the cost and the finished product effect. Additionally, it can be understood that the limitations of the processing accuracy are all less than a specific value because a smaller value of the processing accuracy corresponds to a higher processing accuracy.

[0103] In addition, by limiting the preset distortion degree to 2%, when the mask 1 prepared is applied to the lithography process to form the AG cover plate, the obtained mask 1 can ensure that no local patch unevenness occurs during the production of the AG cover plate.

[0104] The present invention also relates to a mask 1, as Figure 3 and Figure 4 shown, which is prepared by using the mask manufacturing method in the above embodiment.

[0105] When the mask 1 prepared by using the mask manufacturing method in the above embodiment is used to process the AG cover plate, the obtained AG cover plate has a high effect and good appearance uniformity.

[0106] The present invention also relates to an AG cover plate, which is lithographed based on the mask 1 in the above embodiment. Similarly, the AG cover plate lithographed by using the mask 1 obtained by the above mask manufacturing method has the characteristics of high effect and good appearance uniformity.

[0107] The technical features of the above embodiments can be combined arbitrarily. For the sake of brief description, not all possible combinations of the technical features in the above embodiments are described. However, as long as these combinations of technical features do not conflict, they should be considered as within the scope described in this specification.

[0108] The above embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed. However, it should not be construed as a limitation to the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for evaluating the manufacturing precision of a photomask, characterized in that, The evaluation method includes the following steps: Provide a preset pattern for forming a through hole on a photomask; Provide a processing accuracy; Simulate the area of the actual pattern when forming the through hole according to the processing accuracy; Subtract the area of the preset pattern from the area of the actual pattern and take the absolute value; Divide the absolute value by the area of the preset pattern to obtain the actual distortion; Evaluate the manufacturing accuracy of the photomask according to the actual distortion; The step of simulating the actual pattern when forming the through hole according to the processing accuracy includes the following steps: Draw a processed micro-pattern according to the processing accuracy; Fully fill a number of the processed micro-patterns in the preset pattern to form an actual pattern; Read out the number of the processed micro-patterns in the preset pattern to obtain the area of the actual pattern; The step of reading out the number of the processed micro-patterns in the preset pattern includes the following steps: Perform area segmentation on the processed micro-patterns that are not completely located within the preset pattern to obtain the area within the circle located within the preset pattern; Divide the area within the circle by the area of the processed micro-pattern to obtain the actual area ratio; Set a minimum value of the area ratio; Compare the actual area ratio with the minimum value of the area ratio to determine the effectiveness of the processed micro-patterns that are not completely located within the preset pattern; The step of comparing the actual area ratio with the minimum value of the area ratio to determine the effectiveness of the processed micro-patterns that are not completely located within the preset pattern includes: The processed micro-patterns with an actual area ratio higher than the minimum value of the area ratio are effective, and vice versa; 2. The method for evaluating the manufacturing precision of a photomask according to claim 1, wherein The minimum value of the area ratio is not less than 50%; 3. The method for evaluating the manufacturing precision of a photomask according to any one of claims 1-2, characterized in that, The step of evaluating the manufacturing accuracy of the photomask according to the actual distortion includes the following steps: Provide a preset distortion; Compare the actual distortion with the preset distortion to evaluate the manufacturing accuracy of the photomask; 4. The method for evaluating the manufacturing precision of a photomask according to claim 3, wherein The preset distortion is not higher than 2%; 5. A method for manufacturing a photomask, characterized in that, The photomask manufacturing method includes the following steps: Provide a substrate; Form a chromium film on the substrate; Provide a preset pattern; Provide a preset distortion; Determine the range of the processing accuracy according to the preset pattern and the preset distortion; The processing accuracy calculates the actual distortion by using the photomask manufacturing accuracy evaluation method as described in claim 1, and compares the actual distortion with the preset distortion to determine the processing accuracy; Select a laser according to the range of the processing accuracy; Process the chromium film with the laser to form a through hole on the chromium film, thereby manufacturing a photomask; 6. The photomask manufacturing method according to claim 5, characterized in that, The preset distortion is not higher than 2%; 7. A photomask, characterized in that, Prepared by using the photomask manufacturing method as described in claim 5 or 6; 8. An AG cover plate, characterized in that, The AG cover plate is lithographed based on the photomask as described in claim 7;

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