Mask plate and layout generation method
By forming aligned patterns with the same shape and the same horizontal coordinate on the photomask, the problem of overlay error caused by thermal expansion of the photomask is solved, thus improving the alignment accuracy and precision of the photolithography process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUA HONG SEMICON WUXI LTD
- Filing Date
- 2026-01-21
- Publication Date
- 2026-05-12
AI Technical Summary
Existing photomasks are prone to thermal expansion after prolonged exposure, resulting in significant overprinting errors that are difficult to compensate for effectively by the system. This is especially true when light transmittance is low, exposure energy is high, and the number of exposures is high, leading to significant differences between individual photomasks.
Alignment patterns with the same shape and horizontal coordinate are formed on the photomask and located on the edge regions on both sides of the central region. These alignment patterns are used to offset the exposure pattern shift caused by thermal expansion, thereby improving alignment accuracy.
It effectively offsets the overlay error caused by thermal expansion of the photomask, improving the alignment accuracy and precision of the photolithography process.
Smart Images
Figure CN122018228A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor devices and integrated circuit technology, and in particular to a method for generating a photomask and a layout. Background Technology
[0002] In the fabrication of semiconductor devices, multiple thin film layers are typically stacked, and the desired patterns are formed in each layer. When performing photolithography on the current thin film layer, the alignment mark in the current thin film layer needs to be aligned with the alignment mark formed in the previous thin film layer so that the pattern in the current thin film layer is formed at the target location.
[0003] In practical applications, various errors can cause deviations between the pattern formed during photolithography and the target position, resulting in overlay (OVL) errors. Due to these overlay errors, OVL measurement has become a crucial method for monitoring alignment accuracy in photolithography. The performance of overlay errors is influenced by multiple factors. Regardless of whether the measured value of the overlay error is large or small, when the overlay error is stable, the desired exposure effect can be achieved through compensation by an advanced process control (APC) system.
[0004] However, when a hard mask (also known as a photomask) is exposed for an excessively long time, it is prone to thermal expansion and deformation. This is especially true when the mask has a low clear ratio, high exposure energy, and too many exposures. In such cases, the measured overlay error of wafers in the same batch may show an overall decreasing or increasing trend, with significant differences between wafers that are difficult to compensate for effectively through the system. Therefore, there is an urgent need to provide a hard mask that can reduce the large deviations in overlay error caused by excessively long exposure times. Summary of the Invention
[0005] This application provides a method for generating a photomask and a layout, which can solve the problem of large overprinting errors caused by excessively long exposure times in the photomasks provided in related technologies.
[0006] On one hand, embodiments of this application provide a photomask, on which the pattern formed includes: The main pattern is used to form a target structure, which is a structure in a semiconductor device product. The main pattern is formed in the central region of the photomask. The central region is a rectangular region centered on the center of the photomask. The length of the central region is less than the length of the photomask, and the width of the central region is less than the width of the photomask. A first alignment pattern is formed in a first edge region of the mask template, and the first edge region is located on one side of the central region along the longitudinal axis. The second alignment pattern is formed in the second edge region of the mask template. The second edge region is located on the other side of the central region along the vertical axis. The first alignment pattern and the second alignment pattern have the same shape, and the horizontal coordinate of the first alignment pattern and the horizontal coordinate of the second alignment pattern are the same.
[0007] In some embodiments, when the mask is used for exposure, alignment is performed using the first alignment pattern and the second alignment pattern to counteract the exposure pattern offset caused by thermal expansion of the mask.
[0008] In some embodiments, the first distance and the second distance are equal, the first distance being the distance between the side length of the first alignment pattern and its nearest mask along the longitudinal axis, and the second distance being the distance between the side length of the second alignment pattern and its nearest mask along the longitudinal axis.
[0009] On the other hand, embodiments of this application provide a method for generating a layout, including: A main graphic is inserted into the central region, the main graphic being used to form a target structure, the target structure being a structure in a semiconductor device product, the central region being a rectangular region centered on the center of the layout, the length of the central region being less than the length of the layout, and the width of the central region being less than the width of the layout; A first alignment pattern is inserted into a first edge region, wherein the first edge region is located on one side of the central region along the longitudinal axis. A second alignment pattern is inserted into a second edge region, which is located on the other side of the central region along the vertical axis. The first alignment pattern has the same shape as the second alignment pattern, and the horizontal coordinate of the first alignment pattern is the same as that of the second alignment pattern.
[0010] In some embodiments, inserting the second alignment pattern into the second edge region includes: Obtain the x-coordinate of the first aligned graphic; Insert the second alignment pattern into the second edge region such that the horizontal coordinate of the second alignment pattern is the same as the horizontal coordinate of the first alignment pattern.
[0011] In some embodiments, the first distance and the second distance are equal, the first distance being the distance between the side length of the first aligned graphic and its nearest layout along the vertical axis, and the second distance being the distance between the side length of the second aligned graphic and its nearest layout along the vertical axis.
[0012] The technical solution of this application has at least the following advantages: By forming alignment patterns with the same shape and the same horizontal coordinate in the two edge regions of the photomask along the vertical axis, the exposure pattern offset caused by thermal expansion of the photomask can be offset, thereby solving the problem of large overlay error value deviation caused by excessive exposure time of the photomask and improving the alignment accuracy and precision of the photolithography process. Attached Figure Description
[0013] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0014] Figure 1 This is a top view of a mask template provided in an exemplary embodiment of this application; Figure 2 This is a flowchart of a layout generation method provided in an exemplary embodiment of this application. Detailed Implementation
[0015] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0016] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0017] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0018] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.
[0019] refer to Figure 1 It shows a top view of a mask template provided in an exemplary embodiment of this application, such as... Figure 1 As shown, the area on the photomask 100 used to form a pattern includes a central region 110 and a first edge region 121 and a second edge region 122 located on both sides of the central region 110 along the longitudinal axis (Y-axis). The pattern formed on the photomask 100 includes: The main pattern 111 is used to form a target structure, which is the structure of a corresponding semiconductor device on the thin film layer exposed by the mask 100 (e.g., the target structure may be a gate, doped region, metal interconnect, or contact hole of the semiconductor device). The main pattern 111 is formed in the central region 110.
[0020] The central region 110 is a rectangular region centered on the center of the mask template 100. The length of the central region 110 is less than the length of the mask template 100, and the width of the central region 110 is less than the width of the mask template 100.
[0021] The first alignment pattern 201 is formed in the first edge region 121, which is located on one side of the center region 110 along the vertical axis. The vertical axis and the horizontal axis (X-axis) can be set according to actual needs. For example, if the mask 100 is rectangular (ignoring its thickness and approximating it as a rectangle), the direction of the length of the rectangle can be defined as the vertical axis, and the direction of the width of the rectangle can be defined as the horizontal axis.
[0022] The second alignment pattern 202 is formed in the second edge region 122, which is located on the other side of the central region 110 along the vertical axis. The first alignment pattern 201 and the second alignment pattern 202 have the same shape (for example, if the first alignment pattern 201 is a rectangle, the second alignment pattern 202 is a rectangle with the same size as the first alignment pattern 201; if the first alignment pattern 201 is a cross, the second alignment pattern 202 is a cross with the same size as the first alignment pattern 201; if the first alignment pattern 201 is a square, the second alignment pattern 202 is a square with the same size as the first alignment pattern 201). The horizontal coordinate of the first alignment pattern 201 is the same as the horizontal coordinate of the second alignment pattern 202.
[0023] The coordinates of the alignment pattern can be the coordinates of one or more reference points on the pattern. For example, if the first alignment pattern 201 and the second alignment pattern 202 are rectangles, their upper left corner endpoints can be used as reference points, and their coordinates are the coordinates of the alignment pattern. If the coordinates of the reference point of the first alignment pattern 201 are (x1, y1), then the coordinates of the reference point of the second alignment pattern 202 are (x2, y2). Furthermore, the first distance d1 and the second distance d2 are equal. The first distance d1 is the distance between the side length of the first alignment pattern 201 and its nearest mask 100 along the vertical axis, and the second distance d2 is the distance between the side length of the second alignment pattern 202 and its nearest mask 100 along the vertical axis. In addition, it should be noted that multiple first alignment patterns and multiple second alignment patterns can be formed on the mask (the number of first alignment patterns and second alignment patterns are the same and correspond one-to-one), and each first alignment pattern and its corresponding second alignment pattern satisfy the above requirements.
[0024] When the mask 100 is used for exposure, alignment is performed using the first alignment pattern 201 and the second alignment pattern 202 to counteract the exposure pattern shift caused by thermal expansion of the mask 100. The direction of the exposure pattern shift is as follows: Figure 1 The direction indicated by the middle arrow.
[0025] In summary, in this embodiment of the application, by forming alignment patterns with the same shape and the same horizontal coordinate in the two edge regions of the photomask along the vertical axis, the exposure pattern offset caused by thermal expansion of the photomask can be offset, thereby solving the problem of large overlay error value deviation caused by excessive exposure time of the photomask, and improving the alignment accuracy and precision of the photolithography process.
[0026] refer to Figure 2 It illustrates a flowchart of a layout generation method provided in an exemplary embodiment of this application, wherein the layout generated by the method is consistent with... Figure 1 In the embodiments, the mask template corresponds to, such as Figure 2As shown, the method includes: Step S1: Insert the main graphic into the central region. The main graphic is used to form the target structure, which is the structure in the semiconductor device product. The central region is a rectangular area centered on the center of the layout. The length of the central region is less than the length of the layout, and the width of the central region is less than the width of the layout.
[0027] For example, Figure 2 The layout in the embodiment and Figure 1 The mask template 100 in the embodiment corresponds to, Figure 2 The main graphic in the embodiment and Figure 1 The main graphic 111 in the embodiment corresponds to, Figure 2 The central area in the embodiment and Figure 1 The central region 110 in the embodiment corresponds to a schematic diagram after the main graphic is inserted into the central region, which can be referred to here. Figure 1 This will not be elaborated upon here.
[0028] Step S2: Insert the first aligned pattern into the first edge region, the first edge region being located on one side of the center region along the vertical axis.
[0029] For example, Figure 2 The first edge region in the embodiment and Figure 1 The first edge region 121 in the embodiment corresponds to, Figure 2 The first alignment pattern in the embodiment and Figure 1 The first alignment pattern 201 in the embodiment corresponds to a schematic diagram after the first alignment pattern is inserted into the first edge region. Figure 1 This will not be elaborated upon here.
[0030] Step S3: Insert the second alignment pattern into the second edge region. The second edge region is located on the other side of the center region along the vertical axis. The first alignment pattern and the second alignment pattern have the same shape, and the horizontal coordinate of the first alignment pattern and the horizontal coordinate of the second alignment pattern are the same.
[0031] For example, Figure 2 The second edge region in the embodiment and Figure 1 The first edge region 122 in the embodiment corresponds to, Figure 2 The second alignment pattern in the embodiment and Figure 1 The second alignment pattern 202 in the embodiment corresponds to a schematic diagram after the second alignment pattern is inserted into the second edge region. Figure 1 This will not be elaborated upon here.
[0032] The x-coordinate of the first aligned graphic can be obtained; the second aligned graphic is inserted into the second edge region, ensuring that the x-coordinate of the second aligned graphic is the same as that of the first aligned graphic, thus completing the insertion of the second aligned graphic. It should be noted that... Figure 1The same implementation method applies; the layout may include multiple first alignment patterns and multiple second alignment patterns (the number of first alignment patterns and second alignment patterns are the same and they correspond one-to-one), and each first alignment pattern and its corresponding second alignment pattern satisfy the above requirements. The coordinates of the alignment patterns can be referenced. Figure 1 Examples are not detailed here.
[0033] Furthermore, the first distance and the second distance are equal. The first distance is the distance between the side length of the first aligned graphic and its nearest plot along the vertical axis, and the second distance is the distance between the side length of the second aligned graphic and its nearest plot along the vertical axis. (See reference...) Figure 1 In the embodiment, the first distance d1 and the second distance d2 are equal.
[0034] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.
Claims
1. A photomask, characterized in that, The pattern formed on the photomask includes: The main pattern is used to form a target structure, which is a structure in a semiconductor device product. The main pattern is formed in the central region of the photomask. The central region is a rectangular region centered on the center of the photomask. The length of the central region is less than the length of the photomask, and the width of the central region is less than the width of the photomask. A first alignment pattern is formed in a first edge region of the mask template, and the first edge region is located on one side of the central region along the longitudinal axis. The second alignment pattern is formed in the second edge region of the mask template. The second edge region is located on the other side of the central region along the vertical axis. The first alignment pattern and the second alignment pattern have the same shape, and the horizontal coordinate of the first alignment pattern and the horizontal coordinate of the second alignment pattern are the same.
2. The mask template according to claim 1, characterized in that, When the mask is used for exposure, alignment is performed using the first alignment pattern and the second alignment pattern to counteract the exposure pattern offset caused by thermal expansion of the mask.
3. The mask template according to claim 2, characterized in that, The first distance and the second distance are equal. The first distance is the distance between the side length of the first aligned pattern and its nearest mask along the vertical axis, and the second distance is the distance between the side length of the second aligned pattern and its nearest mask along the vertical axis.
4. A method for generating a map layout, characterized in that, include: A main graphic is inserted into the central region, the main graphic being used to form a target structure, the target structure being a structure in a semiconductor device product, the central region being a rectangular region centered on the center of the layout, the length of the central region being less than the length of the layout, and the width of the central region being less than the width of the layout; A first alignment pattern is inserted into a first edge region, wherein the first edge region is located on one side of the central region along the longitudinal axis. A second alignment pattern is inserted into a second edge region, which is located on the other side of the central region along the vertical axis. The first alignment pattern has the same shape as the second alignment pattern, and the horizontal coordinate of the first alignment pattern is the same as that of the second alignment pattern.
5. The method according to claim 4, characterized in that, The insertion of the second aligned pattern into the second edge region includes: Obtain the x-coordinate of the first aligned graphic; Insert the second alignment pattern into the second edge region such that the horizontal coordinate of the second alignment pattern is the same as the horizontal coordinate of the first alignment pattern.
6. The method according to claim 5, characterized in that, The first distance and the second distance are equal. The first distance is the distance between the side length of the first aligned graphic and its nearest plot along the vertical axis, and the second distance is the distance between the side length of the second aligned graphic and its nearest plot along the vertical axis.