Photomask inspection method

Abstract

The invention provides a photomask inspection method, and relates to the technical field of photomask processing. The photomask inspection method comprises the steps that a to-be-detected photomask is provided, the to-be-detected surface of the to-be-detected photomask is formed by splicing at least two materials, and the horizontal heights of different positions on the to-be-detected surface are different; continuously scanning the to-be-detected surface to obtain height values of different positions of the to-be-detected surface; and acquiring distribution position data of various materials on the to-be-detected surface according to the height value. According to the photomask inspection method, the distribution position data of each material on the to-be-detected surface of the whole to-be-detected photomask can be obtained, so that whether processing of each area on the to-be-detected photomask is qualified or not is judged, and the risk that an unqualified photomask flows to a client is effectively reduced.

Description

Technical Field

[0001] This application relates to the technical field of photomask processing, and more particularly, to a photomask inspection method. Background Art

[0002] A photomask is generally obtained by stacking multiple raw materials layer by layer and then undergoing processes such as exposure and etching. Therefore, multiple materials coexist in the photomask, and patterns of different materials are formed at different positions. For information on how various materials are distributed on the photomask, there are currently two main ways to confirm: The first way is to query the data source for confirmation. This method relies on the accuracy of the data source and cannot confirm whether the entire photomask is accurately fabricated according to the data source, and cannot perform point-to-point confirmation of the overall condition of the photomask with the data source. The second way is to perform inspection and confirmation on key areas of the photomask. This method only inspects key areas of the photomask, and if there are identification errors or phase errors in non-key areas, they cannot be discovered in a timely manner.

[0003] Therefore, neither of the above two methods can obtain data on the actual distribution positions of various materials on the entire photomask. If an error is not discovered in a timely manner and flows to the client, it will affect the client's use. Summary of the Invention

[0004] The purpose of this application is to provide a photomask inspection method that can obtain data on the actual distribution positions of various materials on the entire photomask for the deficiencies in the above-mentioned existing technologies.

[0005] To achieve the above purpose, the technical solutions adopted in the embodiments of this application are as follows:

[0006] The embodiments of this application provide a photomask inspection method, including: providing a photomask to be detected, where the surface to be detected of the photomask to be detected is composed of at least two materials spliced together, and the horizontal heights at different positions on the surface to be detected are different; continuously scanning the surface to be detected to obtain height values at different positions on the surface to be detected; and obtaining distribution position data of various materials on the surface to be detected based on the height values.

[0007] Optionally, obtaining distribution position data of various materials on the surface to be detected based on the height values includes: obtaining a height map of the surface to be detected based on the height values; and obtaining distribution position data of various materials on the surface to be detected based on the height map.

[0008] Optionally, after obtaining distribution position data of various materials on the surface to be detected, the photomask inspection method further includes: extracting distribution position data of a preset material and obtaining a distribution map of the preset material based on the distribution position data.

[0009] Optionally, after obtaining the distribution position data of various materials on the surface to be detected according to the height values, the photomask inspection method further includes: comparing the distribution position data of various materials with the distribution position data sources of various materials, and marking the different positions.

[0010] Optionally, comparing the distribution position data of various materials with the distribution position data sources of various materials and marking the different positions includes: comparing the distribution position data of various materials with the distribution position data sources of various materials, and marking the different positions that exceed a preset difference threshold.

[0011] Optionally, continuously scanning the surface to be detected to obtain the height values at different positions on the surface to be detected includes: dividing the surface to be detected into multiple regions, and continuously scanning the multiple regions respectively; combining the scanning results of the multiple regions to obtain the height values at different positions on the surface to be detected.

[0012] Optionally, dividing the surface to be detected into multiple regions includes: dividing the surface to be detected into multiple regions along a first direction, and the multiple regions extend along a second direction, where one of the first direction and the second direction is the length direction of the surface to be detected and the other is the width direction of the surface to be detected.

[0013] Optionally, continuously scanning the surface to be detected includes: continuously scanning the surface to be detected using reflected light or transmitted light.

[0014] Optionally, after obtaining the distribution position data of various materials on the surface to be detected according to the height values, the photomask inspection method further includes: comparing the distribution position data of various materials with the distribution position data sources of various materials to obtain the defect data on the photomask to be detected.

[0015] Optionally, the position distribution data is color data or numerical data.

[0016] The beneficial effects of the present application include:

[0017] The present application provides a photomask inspection method, including: providing a photomask to be detected, where the surface to be detected of the photomask to be detected is composed of at least two materials spliced together, and the horizontal heights at different positions on the surface to be detected are different; continuously scanning the surface to be detected to obtain the height values at different positions on the surface to be detected; obtaining the distribution position data of various materials on the surface to be detected according to the height values. This photomask inspection method can obtain the distribution position data of each material on the surface to be detected of the entire photomask to be detected, so as to judge whether the processing of each region on the photomask to be detected is qualified, effectively reducing the risk of unqualified photomasks flowing to the client. Description of the Drawings

[0018] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0019] Figure 1 One of the flowcharts of the photomask inspection method provided by the embodiments of the present application;

[0020] Figure 2 A cross-sectional view of the photomask to be detected provided by the embodiments of the present application;

[0021] Figure 3 A top view of the photomask to be detected provided by the embodiments of the present application;

[0022] Figure 4 One of the flowcharts of the photomask inspection method provided by the embodiments of the present application;

[0023] Figure 5 One of the flowcharts of the photomask inspection method provided by the embodiments of the present application;

[0024] Figure 6 One of the flowcharts of the photomask inspection method provided by the embodiments of the present application;

[0025] Figure 7 One of the flowcharts of the photomask inspection method provided by the embodiments of the present application;

[0026] Figure 8 One of the flowcharts of the photomask inspection method provided by the embodiments of the present application;

[0027] Icon: 10 - Photomask to be detected; 11 - Surface to be detected; H - Etching depth; X - Laminating direction. Specific embodiments

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Usually, the components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] Accordingly, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but merely represents selected embodiments of the present application. It should be noted that, without conflict, the various features in the embodiments of the present application can be combined with each other, and the combined embodiments are still within the protection scope of the present application.

[0030] It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0031] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of this application is customarily placed during use. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0032] In the description of the present application, it should also be noted that unless otherwise clearly specified and defined, the terms "arranged", "installed", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0033] Please refer to Figure 1 , the embodiments of the present application provide a photomask inspection method, including:

[0034] S100: Provide a photomask to be detected, wherein the surface to be detected of the photomask to be detected is composed of at least two materials spliced together, and the horizontal heights at different positions on the surface to be detected are different.

[0035] Please refer to in combination Figure 2 and Figure 3 , Figure 2 and Figure 3FIG. 0 is a schematic structural diagram of the mask 10 to be detected. Different colors in the figure represent different materials. The mask 10 to be detected is generally obtained by stacking multiple materials layer by layer and then undergoing processes such as exposure and etching. Since the etching depth H of each region on the surface of the mask 10 to be detected is different, the materials exposed at different regions of the surface 11 to be detected of the mask to be detected may be different, and the thickness of the remaining materials is also different.

[0036] S200: Continuously scan the surface to be detected to obtain the height values at different positions on the surface to be detected.

[0037] Continuously scan the surface 11 to be detected of the mask to be detected, so as to obtain the height values at different positions on this surface. The height value is the vertical distance between different positions on the surface of the mask to be detected and the same reference plane, and the reference plane is parallel to the stacking direction X of each material in the mask to be detected.

[0038] It should be noted that in this embodiment, the method for obtaining the height value by scanning is not limited, as long as the height values at different positions on the surface 11 to be detected can be obtained. For example, the surface 11 to be detected is continuously scanned by using reflected light or transmitted light. That is, reflected light or transmitted light is emitted to a preset position, and the height information can be simulated according to the signal difference at each position, and then the distribution position of the material can be simulated. For example, according to the time when the reflected light returns to the emission point or the time when the transmitted light penetrates the mask 10 to be detected, the height value at this preset position is determined. By continuously emitting reflected light or transmitted light to different positions on the surface 11 to be detected, the height values at different positions on the surface 11 to be detected can be obtained. Of course, the scanning of the surface 11 to be detected is not limited to transmitted light or reflected light, and any method such as atomic force that can obtain height values can be used.

[0039] S300: Obtain the distribution position data of various materials on the surface to be detected according to the height values.

[0040] Since the thickness of each material layer is uniform and certain before the mask 10 to be detected is etched, therefore, by analyzing the height values at different positions on the surface 11 to be detected of the mask to be detected, the etching depth H at the corresponding position can be judged, and then according to the etching depth H, the material exposed at this position can be determined, so as to obtain the distribution position data of various materials on the surface 11 to be detected. The position distribution data can be color data or numerical data, and both color data and numerical data can reflect the height difference. Of course, the position data can also be other forms of expression that can reflect the height difference.

[0041] For example, the mask to be detected is formed by stacking three materials layer by layer. The thicknesses of the three materials are 40nm, 30nm, and 20nm respectively, so the total thickness of the semi-finished thin sheet is 90nm. At this time, the surface of the semi-finished thin sheet only includes one material (the topmost material), and the height values at different positions on the surface of the semi-finished thin sheet are all certain, assumed to be A1. After exposing and etching the surface of the semi-finished thin sheet, the semi-finished thin sheet becomes the mask to be detected. At this time, the height values at different positions on the surface 11 to be detected of the mask to be detected obtained by scanning will vary due to the different etching depths H. Assume that the height value measured at the preset position at this time is A2. Then, through the difference between A2 and A1, it is possible to determine how deep the preset position has been etched, and thus it is also possible to determine the material exposed on the surface at the preset position. For example, if it is calculated that the preset position has been etched by 20nm, it can be determined that the material exposed at the preset position is the middle layer material.

[0042] The above mask inspection method can obtain the distribution position data of each material on the surface 11 to be detected of the entire mask to be detected, so as to determine whether the processing of each area on the mask to be detected is qualified, effectively reducing the risk of unqualified masks flowing to the client.

[0043] Optionally, please refer to Figure 4 , obtaining the distribution position data of various materials on the surface to be detected according to the height value includes:

[0044] S310: Obtain the height map of the surface to be detected according to the height value.

[0045] S320: Obtain the distribution position data of various materials on the surface to be detected according to the height map.

[0046] Please refer to Figure 2 and Figure 3 , mark the height values at different positions on the surface 11 to be detected in a graph, and the height map of the surface 11 to be detected (similar to a contour map) can be obtained. This height map can clearly display the height values at different positions on the surface 11 to be detected, providing the required coordinates for machine equipment that requires coordinate information. According to the height values recorded in the height map, the distribution position data of the materials at the positions corresponding to each height value can be deduced.

[0047] Optionally, please refer to Figure 5 , after obtaining the distribution position data of various materials on the surface to be detected according to the height value, the mask inspection method further includes:

[0048] S400: Extract the distribution position data of the preset material, and obtain the distribution map of the preset material according to the distribution position data.

[0049] Among the distribution position data of various materials, extracting the distribution position data of a certain material and drawing a distribution map based on the distribution position data of this material can help understand the distribution of this material. Extracting the distribution position data of two or more materials and drawing the distribution maps of the corresponding materials can help comparatively understand the distribution of two or more materials.

[0050] Optionally, please refer to Figure 6 , after obtaining the distribution position data of various materials on the surface to be detected according to the height values, the photomask inspection method further includes:

[0051] S500: Compare the distribution position data of various materials with the data sources of the distribution positions of various materials, and mark the different positions.

[0052] Please refer to Figure 3 , the data sources of the distribution positions of various materials come from the design data of the photomask 10 to be detected, which are theoretical data. There will be processing errors in actual processing, and this processing error causes the difference between the distribution position data of various materials and the data sources of the distribution positions of various materials. Comparing the distribution position data of various materials with the data sources of the distribution positions of various materials and marking the different positions can clearly show the positions with processing errors on the surface 11 to be detected. According to the comparison result, it can be judged whether the photomask 10 to be detected meets the processing requirements. If not, it can be repaired or discarded in time to prevent unqualified photomasks from flowing to the client.

[0053] Furthermore, comparing the distribution position data of various materials with the data sources of the distribution positions of various materials and marking the different positions includes:

[0054] Compare the distribution position data of various materials with the data sources of the distribution positions of various materials, and mark the different positions that exceed the preset difference threshold.

[0055] Set a difference threshold. If the difference between the distribution position data of the material at a certain position and the data source of the distribution position is greater than this difference threshold, then mark this position to remind the staff that there may be a large defect at this position and further detection or repair is required. If the difference between the distribution position data of the material at a certain position and the data source of the distribution position is less than or equal to this difference threshold, it means that the processing at this position meets the requirements.

[0056] Optionally, please refer to Figure 7 , continuously scanning the surface to be detected to obtain the height values at different positions on the surface to be detected includes:

[0057] S210: Divide the surface to be detected into multiple regions and continuously scan each of the multiple regions separately.

[0058] S220: Combine the scanning results of multiple regions to obtain the height values at different positions on the surface to be detected.

[0059] Please refer to Figure 3 . Before scanning, first divide the surface 11 to be detected into regions, and then continuously scan each region in turn. Each region will correspond to a scanning result. Finally, combine the scanning results of each region to obtain the height values at different positions on the surface 11 to be detected.

[0060] Furthermore, dividing the surface 11 to be detected into multiple regions includes:

[0061] Divide the surface 11 to be detected into multiple regions along the first direction, and the multiple regions extend along the second direction, where one of the first direction and the second direction is the length direction of the surface 11 to be detected, and the other is the width direction of the surface 11 to be detected.

[0062] Generally speaking, the photomask 10 to be detected is rectangular, and the projection of its surface 11 to be detected is also rectangular. Dividing the surface 11 to be detected into multiple regions along its length direction or width direction can facilitate scanning.

[0063] Optionally, please refer to Figure 8 . After obtaining the distribution position data of various materials on the surface 11 to be detected according to the height values, the photomask inspection method further includes:

[0064] S600: Compare the distribution position data of various materials with the distribution position data sources of various materials to obtain the defect data on the photomask to be detected.

[0065] Abnormalities such as dirt during the photomask manufacturing process will affect the etching depth, resulting in defects. This causes the distribution position data of the materials at the location of the defect to be different from the distribution position data source. Analyzing the difference can obtain the defect data at the corresponding position, so as to repair the photomask 10 to be detected according to the situation of the defect, or discard the photomask 10 to be detected. The defect material can be speculated based on the height value of the defect to define the process or equipment that causes the defect, etc., and lock the source in time to reduce risks. The defect data can be the defect position, defect material, etc.

[0066] It should be understood that although the steps in the foregoing flowcharts are shown sequentially as indicated by the arrows, these steps are not necessarily executed sequentially in the order indicated by the arrows. Unless otherwise clearly stated in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowchart may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0067] The foregoing is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A mask inspection method, characterized in that: include: Providing a photomask to be inspected, wherein a surface to be inspected of the photomask to be inspected is composed of at least two materials spliced ​​together, and different positions on the surface to be inspected have different levels; Continuously scanning the surface to be detected to obtain height values ​​at different positions of the surface to be detected; The distribution position data of various materials on the surface to be detected are obtained according to the height values.

2. The photomask inspection method according to claim 1, wherein: The step of obtaining the distribution position data of various materials on the surface to be detected according to the height value comprises: Acquire a height map of the surface to be detected according to the height value; The distribution position data of various materials on the surface to be detected are obtained according to the height map.

3. The photomask inspection method according to claim 1, wherein: After obtaining the distribution position data of various materials on the surface to be inspected according to the height value, the mask inspection method further includes: The distribution position data of the preset material is extracted, and a distribution map of the preset material is obtained according to the distribution position data.

4. The photomask inspection method according to claim 1, wherein: After obtaining the distribution position data of various materials on the surface to be inspected according to the height value, the mask inspection method further includes: The distribution position data of the various materials are compared with a distribution position data source of the various materials, and the difference positions are marked.

5. The photomask inspection method according to claim 4, wherein: The comparing the distribution position data of the various materials with the distribution position data source of the various materials and marking the difference positions includes: The distribution position data of the various materials are compared with the distribution position data source of the various materials, and the difference positions exceeding the preset difference threshold are marked.

6. The photomask inspection method according to claim 1, wherein: The continuously scanning the surface to be detected to obtain height values ​​at different positions of the surface to be detected includes: Dividing the surface to be inspected into a plurality of regions, and continuously scanning the plurality of regions respectively; The scanning results of the plurality of the regions are combined to obtain height values ​​at different positions on the surface to be detected.

7. The photomask inspection method according to claim 6, wherein: The step of dividing the surface to be detected into a plurality of areas comprises: The surface to be detected is divided into a plurality of regions along a first direction, and the plurality of regions extend along a second direction, wherein one of the first direction and the second direction is a length direction of the surface to be detected, and the other is a width direction of the surface to be detected.

8. The photomask inspection method according to claim 1, wherein: The continuously scanning the surface to be detected comprises: The surface to be detected is continuously scanned using reflected light or transmitted light.

9. The photomask inspection method according to claim 1, wherein: After obtaining the distribution position data of various materials on the surface to be inspected according to the height value, the mask inspection method further includes: The distribution position data of the various materials are compared with the distribution position data source of the various materials to obtain defect data on the mask to be inspected.

10. The photomask inspection method according to claim 1, wherein: The position distribution data is color data or numerical data.

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