Test mask plate
By designing the first and second light-blocking patterns and the light-transmitting area of the test mask, the problem of light leakage from the light-blocking plate of the exposure machine was solved, enabling timely detection of the machine's health status and improving chip yield.
Patent Information
- Application Number
- CN202520711424.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-15
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2035-04-15
AI Technical Summary
Existing exposure equipment may have light leakage problems during use, causing chip areas that do not need to be exposed to be exposed, affecting chip yield, and there is a lack of effective detection methods.
A test mask is designed, comprising first and second light-blocking patterns and a light-transmitting area, to detect light leakage of the light-blocking plate. The judgment is made by comparing the formed photoresist pattern with the pattern when there is no light leakage.
It can detect light leakage from the light shield in a timely manner, ensure the health of the machine, prevent chip areas that do not need to be exposed from being exposed, and improve chip yield.
Smart Images
Figure CN223926753U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the semiconductor field, and in particular to a test mask. Background Technology
[0002] Semiconductor manufacturing typically employs photolithography to etch patterns from a photomask onto the surface of a wafer. During photolithography, the photoresist coated on the wafer is first exposed, making some areas resistant to etching while others are not. The non-resistant photoresist is then removed by development, thus forming the pattern on the wafer surface. Because the area exposed in a single exposure cycle is limited, the area to be exposed on the wafer is usually divided into multiple exposure shots, and each shot is exposed sequentially using a photomask. Each exposure shot includes multiple chip regions, and the corresponding photomask has a pattern corresponding to each chip region within that exposure shot.
[0003] In some cases, it is not desirable to expose the entire exposure unit (which is often located at the edge of the wafer) during photolithography. The goal is to expose only a portion of the chip area. This way, only the pattern of that portion of the chip area is formed after development, avoiding the risk of photoresist residue or stripping after the unwanted chip area is exposed.
[0004] To expose only a portion of the chip area within the exposure unit, existing exposure equipment uses movable light-shielding plates to limit the exposure range. However, the manufacturing process of these light-shielding plates may have defects, and their reliability may change during use, potentially leading to light leakage. The degree of light leakage is related to the opening degree of the light-shielding plate. Given the high chip integration density and small lithography linewidths on current wafers, light leakage can cause unwanted chip areas to be exposed, affecting chip yield. Therefore, it is necessary to detect light leakage to promptly assess the equipment's health and allow for timely corrective action if light leakage is detected and causes a decline in health. Utility Model Content
[0005] In order to detect light leakage of the light shield of the exposure machine and to know the health status of the machine in a timely manner, this utility model provides a test mask.
[0006] The test mask template provided by this utility model includes:
[0007] A first light-shielding pattern is disposed at the boundary of the test mask and defines the interior of the test mask. The first light-shielding pattern includes four first light-shielding strips forming a rectangle.
[0008] At least one second light-shielding pattern is arranged inside the test mask template. The second light-shielding pattern includes four second light-shielding strips forming a rectangle, with each adjacent second light-shielding strip parallel to each of the two adjacent first light-shielding strips.
[0009] The light-transmitting area is located between the first light-blocking strip and the second light-blocking strip, as well as between different second light-blocking strips.
[0010] Optionally, the four first light-shielding strips are connected in sequence to form a closed rectangle; or, at least two adjacent first light-shielding strips are disconnected.
[0011] Optionally, the test mask includes at least two nested second light-blocking patterns; the light-transmitting area includes a first light-transmitting ring located between the first light-blocking pattern and the nearest second light-blocking pattern, a second light-transmitting ring located between the nested at least two second light-blocking patterns, and a square light-transmitting area located within the innermost second light-blocking pattern.
[0012] Optionally, the test mask template includes at least two second light-shielding patterns arranged in a non-nested manner.
[0013] Optionally, in the at least two non-nested second light-shielding patterns, at least two of the second light-shielding patterns are different sizes.
[0014] Optionally, in each of the second light-shielding patterns, the four second light-shielding strips are connected in sequence to form a closed rectangle; or, in at least some of the four second light-shielding strips in the second light-shielding patterns, at least two adjacent second light-shielding strips are disconnected.
[0015] Optionally, the widths of the first and second light-shielding strips are in the range of 10mm to 30mm.
[0016] Optionally, the light-transmitting area includes regions of different widths.
[0017] Optionally, the first light-shielding strip and / or the second light-shielding strip are made of chromium (Cr).
[0018] Optionally, the test mask template further includes:
[0019] At least one third light-shielding pattern is located between the first light-shielding strip and the second light-shielding strip and / or between different second light-shielding strips, wherein the third light-shielding pattern is a solid pattern.
[0020] The test mask provided by this utility model can be used to detect light leakage of the light shield of the exposure machine. During the test, the working parameters of the light shield are set as needed so that the light shield defines the corresponding exposure area within the range of the test mask. After the photoresist on the wafer is exposed and developed, the photoresist pattern formed on the wafer surface can be compared with the photoresist pattern formed when there is no light leakage to determine whether the light shield leaks light and to detect the degree of light leakage. Using the first light shield pattern and the second light shield pattern, it is convenient to detect the residual photoresist in the projection area of the first light shield pattern and the second light shield pattern on the wafer, thereby facilitating the detection of whether the light shield leaks light and the degree of light leakage, and facilitating timely acquisition of the machine health status. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of multiple exposure units on a wafer.
[0022] Figure 2 This is a schematic diagram of a test mask template according to an embodiment of the present invention.
[0023] Figure 3 This is a schematic diagram of a test mask template according to another embodiment of the present invention.
[0024] Figure 4 This is a schematic diagram of a test mask template according to another embodiment of the present invention. Detailed Implementation
[0025] The test mask template of this utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this utility model will become clearer from the following description. It should be understood that the drawings in this specification are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this utility model. It should be understood that spatial relative terms are intended to include different orientations in use or operation other than the orientation of the device as depicted in the figures. For example, if the structure in the figures is inverted or positioned in other different ways (such as rotation), the exemplary term "on" may also include "below" and other orientational relationships.
[0026] Figure 1 The illustration shows four exposure units (shots) on a wafer as an example, and multiple chip region DIEs within each exposure unit, including active chip regions (such as shaded chip region DIEs) and inactive chip regions. (See reference...) Figure 1During exposure, in some exposure units (such as exposure unit 11), each chip area DIE is a valid chip area and therefore needs to be exposed. In this case, exposure can be performed directly using a mask. In some exposure units (such as exposure unit 13), each chip area DIE is a non-valid chip area and therefore is not exposed. In other exposure units (such as exposure unit 12 and exposure unit 14), the valid chip areas need to be exposed, while the non-valid chip areas do not need to be exposed. Therefore, a light-shielding plate is used to limit the exposure range of the mask and block the non-valid chip areas.
[0027] This utility model embodiment relates to a test mask template, which can be used to detect the light leakage of the above-mentioned light shield during operation, so as to know the health status of the machine in a timely manner and avoid the chip area that is not to be exposed due to light leakage, thus affecting the chip yield.
[0028] Reference Figures 2 to 4 In this embodiment of the present invention, the test mask template includes a first light-blocking pattern 110, at least one second light-blocking pattern 120, and a light-transmitting area 130.
[0029] The first light-shielding pattern 110 is disposed at the boundary of the test mask and defines the interior of the test mask; that is, the outer edge of the test mask is the outer edge of the first light-shielding pattern 110. The first light-shielding pattern 110 includes four first light-shielding strips 110a, 110b, 110c, and 110d forming a rectangle. The interior of the test mask defined by the first light-shielding pattern 110 is rectangular, and its size can be set as needed. As an example, the width of the rectangle does not exceed 104 mm and the length is less than 132 nm.
[0030] like Figures 2 to 4 As shown, in some embodiments, the four first light-shielding strips 110a-110d of the first light-shielding pattern 110 are connected sequentially to form a closed rectangle. However, this is not a limitation; in other embodiments, at least two adjacent first light-shielding strips 110a-110d of the first light-shielding pattern 110 may be disconnected. Here, "two adjacent first light-shielding strips" refers to the first light-shielding strips that form the two vertical sides of the rectangle. The width of the first light-shielding strip is, for example, in the range of 10mm to 30mm. The first light-shielding strip can be formed using light-shielding materials known in the art, such as metallic chromium (Cr).
[0031] At least one second light-shielding pattern 120 is arranged inside the test mask. The second light-shielding pattern 120 includes four second light-shielding strips 120a, 120b, 120c, and 120d forming a rectangle. Two adjacent second light-shielding strips are parallel to two adjacent first light-shielding strips. Here, "two adjacent first light-shielding strips" refers to the second light-shielding strips that form the two vertical sides of the rectangle. The light-transmitting area 130 is located between adjacent and parallel first and second light-shielding strips and between adjacent and parallel second light-shielding strips.
[0032] When detecting light leakage using the aforementioned test mask, the test mask replaces the mask used in the normal production process. Based on the requirements of the normal production process, the operating parameters of the light-shielding plate are set so that a portion of the test mask is blocked, preventing the corresponding pattern from being transferred to the wafer. The area not blocked by the light-shielding plate is the exposure area to be transferred to the wafer. Because of the first light-shielding pattern 110, the second light-shielding pattern 120, and the light-transmitting area 130 set on the test mask, after exposing and developing the photoresist in the corresponding area on the wafer through the exposure area, the photoresist pattern formed on the wafer surface can be compared with the pattern formed when there is no light leakage. This allows for determination of whether the light-shielding plate is leaking light and detection of the degree of light leakage, thereby enabling timely assessment of the machine's health status. The exposure area defined by the light-shielding plate can be located at different positions on the test mask, and the size of the exposure area can also be adjusted as needed. By changing the size of the exposure area defined by the light-shielding plate, the degree of light leakage under different opening degrees of the light-shielding plate can be compared.
[0033] The aforementioned second light-shielding pattern 120 is located inside the test mask, i.e., nested within the first light-shielding pattern 110. The number of second light-shielding patterns 120 located inside the test mask can be set as needed; for example, the width of the light-transmitting area 130 can be reduced by increasing the number of second light-shielding patterns. The width of the light-transmitting area 130 refers to the distance between the first light-shielding strip and the second light-shielding strip defining the light-transmitting area 130, or the distance between two adjacent second light-shielding strips defining the light-transmitting area 130. The width of the second light-shielding strip is, for example, in the range of 10mm to 30mm. The second light-shielding strip can be formed using light-shielding materials known in the art, such as metallic chromium (Cr). Figure 2 As shown, in some embodiments, the four second light-shielding strips 120a-120d in each second light-shielding pattern 120 are connected sequentially to form a closed rectangle, for example. However, this is not the only possibility. Figure 3 As shown, in some embodiments, at least two adjacent second light-shielding strips 120a to 120d in at least a portion of the second light-shielding pattern 120 are disconnected.
[0034] like Figure 2As shown, in some embodiments, the test mask includes at least two nested second light-blocking patterns 120, and the light-transmitting area 130 includes a first light-transmitting ring 131 located between the first light-blocking pattern 110 and the nearest second light-blocking pattern 120, a second light-transmitting ring 132 located between the at least two nested second light-blocking patterns 120, and a square light-transmitting area 133 located within the innermost second light-blocking pattern 120. The widths of the first light-transmitting ring 131 and the second light-transmitting ring 132 may be the same or different.
[0035] This utility model is not limited thereto; see reference. Figure 3 In some embodiments, the test mask may include at least two non-nested second light-shielding patterns 120, that is, at least two second light-shielding patterns 120 do not surround each other. The light-transmitting area 130 is located between the first light-shielding pattern 110 and the second light-shielding pattern 120, between the at least two non-nested second light-shielding patterns 120, and within the second light-shielding pattern 120. Figure 3 As shown, multiple second light-shielding patterns 120 can be distributed dispersedly inside the first light-shielding pattern 110, and the two adjacent second light-shielding strips in each second light-shielding pattern 120 are parallel to the two adjacent first light-shielding strips in the first light-shielding pattern 110. The size (i.e., the area of the corresponding rectangle) of the at least two non-nested second light-shielding patterns 120 can be the same, or at least two can be different. The size of each second light-shielding pattern 120 can be set as needed. In some embodiments, at least two second light-shielding patterns 120 have equal lengths and equal widths. However, this is not the case; in some embodiments, at least two second light-shielding patterns 120 have unequal lengths or unequal widths.
[0036] This utility model is not limited to, for example Figure 2 The nested arrangement of the various second light-shielding patterns 120 shown and as follows Figure 3 The second light-shielding patterns 120 shown are not nested with each other. For example, in some embodiments, the test mask may include at least two nested second light-shielding patterns 120 as well as at least two non-nested second light-shielding patterns 120 (not shown).
[0037] like Figure 2 and Figure 3 As shown, the light-transmitting area 130 can have at least two different widths at different locations. That is, the light-transmitting area 130 includes areas of different widths, which helps to set the exposure areas defined by the light-shielding plate at different opening degrees using the light-transmitting area 130 areas of different widths, thereby comparing the light leakage degree of the light-shielding plate at different opening degrees.
[0038] Reference Figure 4In some embodiments, the test mask may further include at least one third light-shielding pattern 140, which is located between the first light-shielding strip and the second light-shielding strip and / or between different second light-shielding strips. The third light-shielding pattern 140 is a solid pattern, and its shape can be set as needed, for example, it can be selected from one of polygons, circles, ellipses, and fan shapes. Using the third light-shielding pattern 140, the size of the light-shielding area 130 can be adjusted. When using the test mask to detect the light leakage of the light-shielding plate, the formation of the third light-shielding pattern 140 on the wafer surface can also reflect the light leakage situation.
[0039] The working process of the above test mask template is explained below.
[0040] like Figure 4 As shown, in one embodiment, when detecting light leakage using the above-mentioned test mask, the working parameters of the light-shielding plate are first set so that the light-shielding plate defines an exposure area 101 within the range of the test mask, and the exposure area 101 is located within the light-transmitting area 130; then, the wafer coated with photoresist is exposed and developed using the test mask and the light-shielding plate at the set position; after that, the photoresist pattern formed on the wafer surface is compared with the photoresist pattern formed when there is no light leakage, so as to determine whether the light-shielding plate leaks light and detect the degree of light leakage. Taking positive photoresist as an example, since the exposure area 101 is located within the light-transmitting area 130, the photoresist in the projection area of the exposure area 101 on the wafer will be removed after development. In order to detect light leakage, it is necessary to detect whether the portion of the photoresist that has been removed is larger than the projection area of the exposure area 101. For example, it is possible to detect whether the photoresist in the projection area of the first or second light-blocking strip around the exposure area 101 on the wafer has also been partially removed by development. If so, there is light leakage. By measuring the degree of change of the actual photoresist pattern relative to the photoresist pattern formed when there is no light leakage, the degree of light leakage can be evaluated.
[0041] like Figure 4As shown, in another embodiment, when detecting light leakage using the aforementioned test mask, a light-shielding plate defines an exposure area 102 within the range of the test mask. A portion of the exposure area 102 is located within the light-transmitting area 130, while another portion overlaps with a second light-shielding strip. When determining whether the light-shielding plate leaks light and detecting the degree of light leakage, taking a positive photoresist as an example, due to the light-shielding effect of the second light-shielding strip, when there is no light leakage, the photoresist in the projection area of the second light-shielding strip on the wafer is not exposed and remains on the wafer after development. The photoresist in the projection area of the light-transmitting area 130 on the wafer within the exposure area 102 is removed. When light leakage exists, a portion of the photoresist in the projection area of the corresponding second light-shielding strip on the wafer is removed due to exposure. By detecting the residual photoresist in the projection area of the second light-shielding strip, it is possible to determine whether light leakage occurs and assess the degree of light leakage.
[0042] Reference Figure 4 In another embodiment, when detecting light leakage using the aforementioned test mask, a light-shielding plate is set to define an exposure area 103 within the range of the test mask. The exposure area 103 overlaps with the first light-shielding strip, the second light-shielding strip, or the aforementioned third light-shielding pattern 140 (here, overlapping with a third light-shielding pattern 140 is taken as an example). When determining whether the light-shielding plate leaks light and detecting the degree of light leakage, taking the photoresist as a positive adhesive as an example, since the exposure area 103 is located in the light-shielding area of the test mask, the photoresist will not be exposed when there is no light leakage, and thus will not form a pattern after development. When there is light leakage, the photoresist located in and near the projection area of the exposure area 103 will be exposed and removed after development, so that the photoresist forms a pattern. By detecting the removal of the photoresist, it is possible to determine whether there is light leakage and to assess the degree of light leakage.
[0043] The test mask described in this utility model can be used to detect light leakage in the light shield of an exposure machine. After exposing and developing the photoresist on the wafer using the test mask and the light shield at a set position, by comparing the photoresist pattern formed on the wafer surface with the pattern formed when there is no light leakage, it can be determined whether the light shield is leaking light and to detect the degree of light leakage. This allows for timely assessment of the machine's health status. If light leakage exists and causes a decline in health status, timely corrective measures can be taken. The use of the first light shielding pattern 110 and the second light shielding pattern 120 facilitates the detection of photoresist residue in the projection areas of the first light shielding pattern 110 and the second light shielding pattern 120 on the wafer, thereby conveniently detecting whether the light shield is leaking light and to what extent.
[0044] The above description is only a description of the preferred embodiment of the present utility model and is not intended to limit the scope of the present utility model. Any person skilled in the art can make possible changes and modifications to the technical solution of the present utility model by using the methods and techniques disclosed above without departing from the spirit and scope of the present utility model. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the content of the technical solution of the present utility model shall fall within the protection scope of the technical solution of the present utility model.
Claims
1. A test reticle, characterized in that, The test mask includes: a first light-shielding pattern arranged at a boundary of the test mask and defining an interior of the test mask, the first light-shielding pattern including four first light-shielding strips forming a rectangle; at least one second light-shielding pattern arranged in the interior of the test mask, the second light-shielding pattern including four second light-shielding strips forming a rectangle, adjacent two of the second light-shielding strips being parallel to adjacent two of the first light-shielding strips; and a light-transmitting region between the first light-shielding strips and the second light-shielding strips and between different second light-shielding strips. The four first light-shielding strips are connected in sequence to form a closed rectangle; or, at least two adjacent first light-shielding strips among the four first light-shielding strips are disconnected.
2. The test reticle of claim 1, wherein, The test mask includes at least two second light-shielding patterns arranged in a nested manner; the light-transmitting region includes a first light-transmitting ring between the first light-shielding pattern and the nearest second light-shielding pattern, a second light-transmitting ring between the at least two second light-shielding patterns arranged in a nested manner, and a square light-transmitting region in the innermost second light-shielding pattern.
3. The test reticle of claim 1, wherein, The test mask includes at least two second light-shielding patterns arranged in a non-nested manner.
4. The test reticle of claim 1, wherein, At least two of the second light-shielding patterns arranged in a non-nested manner are different in size.
5. The test reticle of claim 4, wherein, In each of the second light-shielding patterns, the four second light-shielding strips are connected in sequence to form a closed rectangle; or, at least two adjacent second light-shielding strips among the four second light-shielding strips in at least part of the second light-shielding patterns are disconnected.
6. The test reticle of claim 1, wherein, The width of the first light-shielding strips and the second light-shielding strips is in a range of 10 mm to 30 mm.
7. The test reticle of claim 1, wherein, The light-transmitting region includes regions of different widths.
8. The test reticle of claim 1, wherein, The first light-shielding strips and / or the second light-shielding strips are formed of chromium.
9. The test reticle of claim 1, wherein, The test mask further includes:
10. The test reticle according to any one of claims 1 to 9, wherein, at least one third light-shielding pattern between the first light-shielding strips and the second light-shielding strips and / or between different second light-shielding strips, the third light-shielding pattern being a solid pattern.