Photomask defect positioning method and elimination method

Abstract

The application provides a photomask defect positioning method and elimination method. The photomask defect positioning method comprises the following steps: obtaining an electron image in an etching mask layer in a target photomask, the target photomask comprising a transparent substrate layer and a plurality of etching mask layers arranged on the transparent substrate layer, and the etching mask layers having defects; obtaining a position of an image defect in the electron image according to the electron image; determining an actual defect position in the etching mask layer according to the position of the image defect; and performing etching deposition treatment on a surface of the transparent substrate layer according to the actual defect position to form a plurality of positioning points. The application can improve the accuracy and efficiency of photomask defect repair and reduce the situation of repeated repair.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, and in particular to a photomask defect positioning method and elimination method. BACKGROUND

[0002] There are various types of photomask defects, and some special defects have insufficient imaging accuracy on ion repair equipment, which makes it difficult to find defects during the repair process of the operator, and the accurate position of the defects cannot be determined from the imaging interface of the ion beam repair equipment. Especially for photomask chromium oxide layer defects, the chromium oxide layer defects cannot be accurately imaged on the ion repair equipment, which requires a high level of repair experience for the operator, and often leads to incorrect repair position of the operator and repeated repair, which often leads to waste of production capacity, extension of delivery cycle, and even product scrap.

[0003] Therefore, it is necessary to provide a new photomask defect positioning method and elimination method to solve the above problems in the prior art. SUMMARY

[0004] The purpose of the present application is to provide a photomask defect positioning method and elimination method to improve the accuracy and efficiency of photomask defect repair and reduce repeated repair.

[0005] To achieve the above purpose, the photomask defect positioning method comprises:

[0006] Obtaining an electronic image of an etching mask layer in a target photomask, the target photomask comprising a transparent substrate layer and a plurality of etching mask layers arranged on the transparent substrate layer, and the etching mask layer having defects;

[0007] According to the electronic image, the image defect position in the electronic image is obtained;

[0008] According to the image defect position, the actual defect position in the etching mask layer is determined, and etching and deposition processing is performed on the surface of the transparent substrate layer according to the actual defect position to form a plurality of positioning points.

[0009] The photomask defect positioning method has the beneficial effect that after obtaining the electronic image of the target photomask having defects, the actual defect position in the target photomask is determined according to the electronic image, and the positioning points are formed according to the actual defect position, so as to complete the positioning process of the actual defect position of the target photomask, and to improve the accuracy and efficiency of the photomask defect repair and reduce the repeated repair, thereby reducing the waste of production capacity.

[0010] Optionally, the etching and depositing process is performed on the surface of the transparent substrate layer according to the actual defect position to form a plurality of positioning points, and the process comprises the following steps of:

[0011] According to the actual defect position on the etching mask layer, positioning point positions are determined on the transparent substrate layer on both sides of the actual defect position;

[0012] According to the positioning point positions, an electron beam is used to perform etching pretreatment on the positioning point positions;

[0013] A positioning film is deposited on the positioning point positions after the etching pretreatment, and the deposition is repeated multiple times until the thickness of the positioning film reaches a preset thickness;

[0014] The positioning film is etched by using the electron beam to form the positioning points with a preset size.

[0015] Optionally, the positioning points are in a rectangular shape, the length of the line width of the defect position is A, the long side of the positioning point is perpendicular to the line width, and the width of the positioning point is parallel to the line width.

[0016] Optionally, the length of the positioning point is 0.05A to 0.3A, and the width of the positioning point is 0.02A to 0.1A.

[0017] Optionally, in the process of etching and depositing on the surface of the transparent substrate layer according to the actual defect position to form a plurality of positioning points, the process further comprises halo suppression on the positioning point positions, the number of halo suppression is 1 to 6 times, and the pixel amount of halo suppression is 1 to 3000 pixels.

[0018] The application further provides a photomask defect elimination method, which comprises the following steps of:

[0019] A plurality of positioning points are formed on the transparent substrate layer of a target photomask by using the photomask defect positioning method described above;

[0020] After the defect position is positioned according to the positioning points, an ion beam repair device is used to repair the actual defect position;

[0021] The positioning points are removed by the ion beam repair device.

[0022] The photomask defect elimination method has the beneficial effects that after the positioning point is formed on the transparent substrate layer according to the actual defect position of the target photomask through the photomask defect positioning method, the actual defect position is directly positioned, removed and repaired through the positioning point in the elimination process of the photomask defect, the positioning point is removed, and the repair process of the photomask defect position is completed, so that the accuracy and efficiency of the photomask defect position repair are improved, the repeated repair is reduced, and the production capacity waste is reduced.

[0023] Optionally, the removing the positioning point by the ion beam repair device comprises:

[0024] forming a positioning hole at the etching mask layer at the actual defect position;

[0025] positioning the positioning hole as a reference to the positioning point by the ion beam repair device, and aligning the positioning point by the ion beam in the ion beam repair device to remove the positioning point.

[0026] Optionally, in the process of etching the positioning point along the positioning hole by the ion beam repair device to remove the positioning point, the positioning point is scanned three times, and the time of each scanning is different.

[0027] Optionally, the three scans are a first scan, a second scan and a third scan, the time of the first scan is 1 to 500 seconds, the time of the second scan is 1 to 2000 seconds, and the time of the third scan is 1 to 1000 seconds.

[0028] Optionally, the first scan dose is 1% to 50%, and the second scan dose is 1% to 100%.

[0029] Optionally, the repairing the defect position by the ion beam repair device comprises:

[0030] determining a defect area corresponding to the actual defect position in the etching mask layer according to the positioning point;

[0031] etching the defect area to remove defects, and cleaning the defect area;

[0032] depositing a repair material on the defect area to repair the defect area.

[0033] Optionally, the photomask defect elimination method further comprises: spatial imaging the repaired photomask, and determining whether the photomask defect is eliminated according to the spatial imaging result. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 A flow chart of the method for positioning defects of a photomask according to an embodiment of the present application is shown in FIG. 1.

[0035] Figure 2 A schematic diagram of a cross-sectional structure of the photomask according to an embodiment of the present application is shown in FIG. 2.

[0036] Figure 3 A flow chart of the method for eliminating defects of a photomask according to an embodiment of the present application is shown in FIG. 3.

[0037] Figure 4 A schematic diagram of a top view of the photomask in the method for eliminating defects of a photomask according to an embodiment of the present application is shown in FIG. 4. DETAILED DESCRIPTION

[0038] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application. Unless otherwise defined, the technical terms or scientific terms used herein should be understood as the common meanings by those skilled in the art to which the present application belongs. The terms such as “comprise” and the like used herein mean that the elements or objects before the terms encompass the elements or objects listed after the terms and equivalents thereof, and do not exclude other elements or objects.

[0039] In view of the problems in the prior art, the embodiments of the present application provide a method for positioning defects of a photomask, which refers to Figure 1 and comprises the following steps:

[0040] S101, obtaining an electron image in an etching mask layer in a target photomask, the target photomask comprising a transparent substrate layer and a plurality of etching mask layers arranged on the transparent substrate layer, and the etching mask layers having defects.

[0041] In the present embodiment, an electron image of the target photomask is photographed by an electron microscope, so as to quickly obtain the defect position of the target photomask. Since the transparent substrate layer can form an image under an ion repair device, while the etching mask layer cannot form an image under the ion repair device, the defect position in the etching mask layer is positioned by the transparent substrate layer when the etching mask layer has defects.

[0042] S102, obtaining an image defect position in the electron image according to the electron image.

[0043] S103, determining an actual defect position in the etching mask layer according to the image defect position, and performing etching deposition processing on the surface of the transparent substrate layer according to the actual defect position to form a plurality of positioning points.

[0044] For example, referring to Figure 2 The target photomask includes a transparent substrate layer 21 and a plurality of etching mask layers 22 arranged on the transparent substrate layer 21. The transparent substrate layer 21 is made of quartz material, and the etching mask layer 22 includes a chromium layer 221 and a chromium oxide layer 222 from bottom to top. Generally, the chromium oxide layer 222 has defects, and the ion repair equipment cannot identify the actual defect position, so that the defects in the chromium oxide layer of the photomask cannot be accurately removed. In the embodiment, for the target photomask with defects in the chromium oxide layer 222, first, an electron microscope is used to obtain an electron image of the etching mask layer 22 in the target photomask, and then the actual defect position in the photomask is determined according to the image defect position in the electron image. Corresponding etching deposition processing is performed on the surface of the transparent substrate layer to form a plurality of positioning points, so that the actual defect position of the target photomask can be determined according to the positioning points in the subsequent process, and the defect repair of the target photomask is completed. Even if the ion repair equipment cannot accurately image, the actual defect position of the target photomask can also be quickly located through the formed positioning points, so that the waste of production capacity caused by repeated repair due to error of the repair position is avoided, and the defect repair efficiency and accuracy are improved.

[0045] In some embodiments, the etching deposition processing on the surface of the transparent substrate layer according to the actual defect position includes:

[0046] According to the actual defect position on the etching mask layer, the positioning point position is determined on the transparent substrate layer on both sides of the actual defect position.

[0047] According to the positioning point position, an electron beam is used to perform etching pretreatment on the positioning point position.

[0048] A layer of positioning film is deposited at the positioning point position after etching pretreatment, and repeated deposition is performed until the thickness of the positioning film reaches a preset thickness.

[0049] The positioning film is etched by the electron beam to form a positioning point with a preset size.

[0050] In the embodiment, a plurality of positioning point positions are first determined on the transparent substrate layer according to the actual defect position in the photomask layer, so that the positioning points are formed at the positioning point positions, and the actual defect position is positioned through the positioning points when the defect position is repaired subsequently, so that the actual defect position is repaired accurately and efficiently.

[0051] In the embodiment, firstly, the position of the positioning point is etched by electron beam and XeF2, so as to improve the effect of subsequent film deposition. After the film with a preset thickness is deposited, the positioning point with a preset size is obtained by etching with electron beam and XeF2, so as to position the defect position according to the positioning point.

[0052] The film is deposited on the transparent substrate layer 21 by electron beam and ethyl silicate gas to form a positioning film, and the height of the positioning film after deposition is higher than the height of the surface of the transparent substrate layer 21 and lower than the height of the surface of the chromium layer 221.

[0053] In some other embodiments, the shape of the positioning point 3 is rectangular, the line width of the photoetching pattern in the area where the actual defect position is located is A, the long side of the positioning point is perpendicular to the line where the line width is located, and the width of the positioning point is parallel to the line where the line width is located.

[0054] In the embodiment, the shape of the minimum unit after amplification of the structure in the photo mask is usually rectangular, and the positioning point with a rectangular structure can match the structure in the photo mask, so as to improve the forming efficiency of the positioning point.

[0055] For example, the line width of the photoetching pattern is 300 nm, the length of the long side of the positioning point 3 is 0.05A to 0.3A, that is, 15 nm to 90 nm, and the width of the positioning point 3 is 0.02A to 0.1A, that is, 6 nm to 30 nm.

[0056] In some embodiments, the number of deposition cycles in the forming process of the positioning point is 1 to 100.

[0057] In some other embodiments, during the etching and deposition process of the transparent substrate layer according to the actual defect position to form a plurality of positioning points, the position of the positioning point is also subjected to halo suppression, the number of halo suppression is 1 to 5 times, and the pixel amount of halo suppression is 1 to 3000 pixels.

[0058] For example, in the embodiment, the length of the long side of the positioning point is 50 nm, the width of the positioning point is 18 nm, the number of deposition cycles in the forming process of the positioning point is 50, the number of halo suppression is 3, and the pixel amount of halo suppression is 1500 pixels.

[0059] The application also provides a photo mask defect elimination method, referring to Figure 3 , comprising the following steps:

[0060] S301, forming a plurality of positioning points on the transparent substrate layer of the target photomask by using the photomask defect positioning method described above;

[0061] S302, after positioning the actual defect position according to the positioning points, repairing the actual defect position by using an ion beam repair device;

[0062] S303, removing the positioning points by using the ion beam repair device.

[0063] In some embodiments, the removing the positioning points by using the ion beam repair device comprises:

[0064] forming a positioning hole in the etching mask layer at the actual defect position;

[0065] positioning the positioning points by using the positioning hole as a reference and aligning the positioning points by using the ion beam in the ion beam repair device to remove the positioning points.

[0066] In the elimination process of the photomask defect, the defect position is directly positioned by the positioning points so as to remove and repair the defect position, and the positioning points are removed, thereby completing the repair process of the photomask defect position, improving the accuracy and efficiency of the photomask defect position repair, reducing the repeated repair, and reducing the waste of production capacity.

[0067] In the present embodiment, after the positioning points are formed according to the actual defect position of the target photomask by using the photomask defect positioning method described above, the actual defect position of the photomask is first repaired according to the position of the positioning points, and after the repair is completed, a positioning hole is etched in the chromium layer region of the etching mask layer of the photomask so as to position the positioning points by using the positioning hole as a reference, thereby accurately etching the positioning points by using the ion beam repair device to remove the positioning points, thereby completing the repair and removal process of the positioning points of the photomask defect position.

[0068] For example, in the process of removing the positioning points by using the positioning hole, the positioning points formed previously are first selected and aligned by using the ion beam repair device, and the graphical features of the positioning hole are grabbed by using the feature pattern grabbing function of the ion beam repair device, and the positioning points are aligned by using the graphical features of the positioning hole as a reference, thereby ensuring that the ion beam released by the ion beam repair device can be aligned with the positioning points. In the process of etching the positioning points by using the ion beam and cooperating with the gas, the accuracy of the positioning point removal process is improved, and the accuracy of the positioning point removal is avoided to be affected by the vibration or external deviation to cause the photomask to be offset.

[0069] It should be noted that the size of the positioning hole has no effect on the spatial imaging result of the ion beam repair device, so that the positioning hole does not need to be processed after the positioning point is removed.

[0070] In some embodiments, the positioning point is positioned by using the ion beam repair device in cooperation with the positioning hole, the positioning point is removed, and the positioning point is scanned three times, and the time of each scan is different. In the process of etching the positioning point by the ion beam repair device through the ion beam in cooperation with the gas, the ion beam is released by using three scans, so as to control the scanning dose of the ion beam and improve the etching effect of the ion beam.

[0071] For example, the three scans are a first scan, a second scan and a third scan, the time of the first scan is 1 to 500 seconds, the time of the second scan is 1 to 2000 seconds, and the time of the third scan is 1 to 1000 seconds.

[0072] Specifically, the time of the first scan is 250 seconds, the time of the second scan is 1000 seconds, and the time of the third scan is 500 seconds.

[0073] In some embodiments, the first scan dose is 1% to 50%, and the second scan dose is 1% to 100%.

[0074] In some embodiments, the repairing of the defect position by using the ion beam repair device comprises:

[0075] According to the positioning point, the actual defect position corresponding to the defect area in the etching mask layer is determined;

[0076] The defect area is etched to remove the defect, and the defect area is cleaned;

[0077] The defect area is deposited with repair material to repair the defect area.

[0078] For example, referring to Figure 4 After the positioning points 3 are formed at the defect positions of the target photomask by the above-mentioned photomask defect positioning method, the defect positions D in the photolithography mask layer 22 are determined according to the plurality of positioning points 3, that is, the defect areas B in the chromium oxide layer 222 in the photolithography mask layer 22 are determined according to the plurality of positioning points 3, and then the defect areas B are repaired, that is, the repair process of the defect positions D is completed.

[0079] After the defect positions of the photomask chromium oxide layer are determined according to the positioning points, the defect positions are etched, cleaned and deposited with repair material in sequence during the process of removing and repairing the defect positions, so as to complete the positioning and removal process of the defect positions of the photomask.

[0080] It should be noted that in the present embodiment, the method in the prior art is used to remove and repair the defects at the location of the positioning point, but the present solution is not limited thereto, and other methods can also be used to remove and repair the defects at the location of the positioning point, which will not be described herein.

[0081] In yet some embodiments, the photomask defect elimination method further comprises: spatially imaging the repaired photomask, and determining whether the photomask defects are eliminated according to the spatial imaging result

[0082] After the defects at the location of the positioning point are removed and repaired, in order to determine the repair effect, the repaired photomask is spatially imaged, and the repair of the photomask defects is determined according to the imaging result.

[0083] In the present embodiment, after the repaired photomask is spatially imaged, the spatial imaging result is obtained, and when the specifications of the black area result and the white area result in the spatial imaging result both meet the requirements, it is indicated that the repair of the defects of the current photomask meets the requirements, otherwise the photomask needs to be repaired again.

[0084] For example, the specifications of the black area result and the white area result in the spatial imaging result are both 98% to 102%, and reach 90% to 110% of the required specifications, and therefore the repair of the defects of the photomask using the present solution meets the requirements, and can meet the positioning and repair process of the defects of the oxidation barrier layer.

[0085] Although the embodiments of the present application are described in detail above, it is obvious for those skilled in the art that various modifications and changes can be made to the embodiments. However, it should be understood that such modifications and changes all belong to the scope and spirit of the present application described in the claims. Moreover, the present application described herein can have other embodiments, and can be implemented or realized in various ways.

Claims

1. A method for eliminating photomask defects, characterized in that, include: Obtain an electronic image of the etching mask layer in the target photomask. The target photomask includes a transparent substrate layer and several etching mask layers disposed on the transparent substrate layer. The etching mask layers include a chromium layer and a chromium oxide layer from bottom to top. The chromium oxide layer has defects. The location of image defects in the electronic image is obtained based on the electronic image. The actual defect location in the etched mask layer is determined based on the image defect location. An etching deposition process is then performed on the surface of the transparent substrate layer based on the actual defect location to form several positioning points. This includes: determining the positioning point positions on the transparent substrate layer on both sides of the actual defect location based on the actual defect location on the etched mask layer; performing an electron beam etching pre-processing on the positioning point positions based on the positioning point positions; depositing a positioning film at the pre-etched positioning point positions, repeating the deposition process multiple times until the positioning film thickness reaches a preset thickness; and performing an electron beam etching post-processing on the positioning film to form the positioning points of a preset size. After locating the actual defect location based on the positioning point, the actual defect location is repaired using an ion beam repair device; The positioning point is removed using the ion beam repair device.

2. The method for eliminating photomask defects according to claim 1, characterized in that, The positioning point is rectangular in shape, the length of the defect location line is A, the line containing the length of the positioning point is perpendicular to the line containing the line width, and the line containing the width of the positioning point is parallel to the line containing the line width.

3. The method for eliminating photomask defects according to claim 2, characterized in that, The length of the positioning point is 0.05A to 0.3A, and the width of the positioning point is 0.02A to 0.1A.

4. The method for eliminating photomask defects according to claim 1, characterized in that, During the process of etching and depositing a number of positioning points on the surface of the transparent substrate according to the actual defect location, the process also includes halo suppression at the positioning point location. The number of times the halo suppression is performed is 1 to 6, and the number of halo suppression pixels is 1 to 3000 pixels.

5. The method for eliminating photomask defects according to claim 1, characterized in that, The removal of the positioning point by the ion beam repair device includes: A positioning hole is formed by etching the etching mask layer at the actual defect location; The positioning point is located using the positioning hole as a reference by the ion beam repair device, and the positioning point is removed by aligning the ion beam in the ion beam repair device with the positioning point.

6. The photomask defect elimination method according to claim 5, characterized in that, During the process of using the ion beam repair equipment in conjunction with the positioning hole to locate the positioning point and remove it, the positioning point is scanned three times, and the time for each scan is different.

7. The method for eliminating photomask defects according to claim 6, characterized in that, The three scans are the first scan, the second scan, and the third scan. The first scan lasts for 1 to 500 seconds, the second scan lasts for 1 to 2000 seconds, and the third scan lasts for 1 to 1000 seconds. The dose for the first scan is 1% to 50%, and the dose for the second scan is 1% to 100%.

8. The method for eliminating photomask defects according to any one of claims 1 to 7, characterized in that, The repair of the defect location using an ion beam repair device includes: The defect region corresponding to the actual defect location in the etching mask layer is determined based on the positioning point; The defective area is etched to remove the defect, and then the defective area is cleaned. A repair material is deposited on the defective area to repair the defective area.

9. The method for eliminating photomask defects according to claim 1, characterized in that, The photomask defect elimination method further includes: performing spatial imaging on the repaired photomask, and determining whether the photomask defect has been eliminated based on the spatial imaging results.

Images