Method for improving width uniformity of straight edge and inclined edge of line

Abstract

The invention discloses a method for improving the width uniformity of a straight edge and a bevel edge of a line. The method comprises the following steps: S1, providing two product sheets before a photoetching process; s2, gluing: adopting the same gluing condition to obtain two gluing sheets; s3, exposing, namely exposing the two glued films by adopting a layout of a wafer formed by a plurality of distributed crystal grains to obtain two exposed films, aiming at the two glued films, adopting layouts with different line widths at connection positions of bevel edges and adjacent straight edges, connecting the bevel edges with the adjacent straight edges through gradually-shrunk edges, taking the gradually-shrunk edges as the connection positions of the bevel edges and the adjacent straight edges, and taking the gradually-shrunk edges as the connection positions of the bevel edges and the adjacent straight edges; other exposure parameters are the same; s4, developing: developing under the same developing condition to obtain two developing sheets; and S5, selecting a crystal grain, collecting line widths in a plurality of areas of the selected crystal grain, determining the influence of the line width at the connection position of the bevel edge and the adjacent straight edge on the line width uniformity of the connection position of the bevel edge and the adjacent straight edge and the line width uniformity of the straight edge which is not adjacent to the bevel edge in the crystal grain, and determining optimized parameters and processes of batch production of the photoetching process.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductors, and more particularly to a method for improving the uniformity of line widths of straight and oblique edges of lines. Background Art

[0002] In the more than half a century since their introduction, microelectronics and integrated circuit technology have advanced rapidly, with advances in photolithography playing a significant role. The ever-shrinking critical dimensions, a key indicator of photolithography development, have placed higher demands on improving key parameters such as product linewidth uniformity. Further research is needed to improve linewidth uniformity within wafer dies, thereby optimizing processes and increasing product yield. Summary of the Invention

[0003] In view of the problems existing in the background technology, an object of the present disclosure is to provide a method for improving the uniformity of the width of straight edges and oblique edges of lines, which can broaden the optimization direction for improving the uniformity of the width of straight edges and oblique edges of lines.

[0004] Another object of the present disclosure is to provide a method for improving the uniformity of line widths of straight and oblique edges of lines, which can determine the optimized parameters for line width uniformity within a die.

[0005] Another object of the present disclosure is to provide a method for improving the uniformity of the width of straight and oblique edges of lines, which can provide an optimized process for mass production of photolithography processes.

[0006] Therefore, a method for improving the line width uniformity of straight and oblique edges of lines includes the following steps: S1, providing two product sheets before the photolithography process; S2, coating, coating with the same coating conditions to obtain two coated sheets; S3, exposing, exposing the two coated sheets after coating with a layout of a wafer composed of multiple distributed grains to obtain two exposed sheets, wherein, for the two coated sheets, a layout with different line widths at the connection position between the oblique edge and the adjacent straight edge is used, the oblique edge is connected to the adjacent straight edge via a tapered edge, the tapered edge serves as the connection position between the oblique edge and the adjacent straight edge, and the other exposure parameters are the same; S4, developing, developing the two exposed sheets after exposure with the same developing conditions to obtain two developed sheets; S5, selecting grains, collecting line widths in multiple areas of the selected grains, determining the influence of the line width at the connection position between the oblique edge and the adjacent straight edge on the line width uniformity at the connection position between the oblique edge and the adjacent straight edge and the straight edge not adjacent to the oblique edge in the grain, and determining the optimized parameters and optimized process for mass production of the photolithography process.

[0007] The beneficial effects of the present disclosure are as follows.

[0008] In the method for improving the line width uniformity of straight edges and oblique edges of lines according to the present disclosure, the influence of the line width change at the connection position of the oblique edge and the adjacent straight edge in the layout design of the exposure process on the line width uniformity of the connection position of the oblique edge and the adjacent straight edge in the grain and the straight edge not adjacent to the oblique edge is analyzed. As verified by the test process, it can be clearly seen that the line width change at the connection position of the oblique edge and the adjacent straight edge in the layout design will affect the line width uniformity of the connection position of the oblique edge and the adjacent straight edge in the grain and the straight edge not adjacent to the oblique edge, thereby Improving the line width uniformity of the connection between the oblique edge and the adjacent straight edge and the straight edge not adjacent to the oblique edge (i.e., improving the line width uniformity between the straight edge and the oblique edge, or improving the line width uniformity within the grain) broadens the optimization direction and can determine the line width at the connection location of the oblique edge and the adjacent straight edge in the layout design during the exposure process to improve the line width uniformity of the connection location of the oblique edge and the adjacent straight edge and the straight edge not adjacent to the oblique edge (i.e., determining the optimization parameters for line width uniformity within the grain), thereby providing an optimized process for mass production of the lithography process. In addition, since only the line width at the connection location of the oblique edge and the adjacent straight edge in the layout design needs to be changed, there is no need to replace the machine for the exposure process in the lithography process, thereby saving the equipment cost of the lithography process. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the structural relationship between the mask, the film and the grain.

[0010] Figure 2 FIG. 1 is a partial schematic structural diagram of an example of a single crystal grain.

[0011] Figure 3 It is a schematic diagram of the line width collection area division of a single grain.

[0012] Figure 4 yes Figure 2 Schematic structure diagram of a pixel of a single grain.

[0013] Figure 5 This is a photograph of the local morphology of the central pixel in the central area of the nine regions of the grain selected in the center of the wafer when the line width at the connection position of the oblique edge and the adjacent straight edge in the layout design is 0.27μm, the straight edge not adjacent to the oblique edge with the line width size marked, and the connection position between the oblique edge and the adjacent straight edge.

[0014] Figure 6 This is a photograph of the local morphology of the central pixel in the central area of the nine regions of the grain selected in the center of the wafer when the line width at the connection position of the oblique edge and the adjacent straight edge in the layout design is 0.30μm, the straight edge not adjacent to the oblique edge with the line width size marked, and the connection position between the oblique edge and the adjacent straight edge. DETAILED DESCRIPTION

[0015] It will be understood that the disclosed embodiments are merely examples of the present disclosure, which can be implemented in various forms. Therefore, the specific details disclosed herein should not be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously implement the present disclosure.

[0016] [Methods to improve the uniformity of straight and oblique line widths]

[0017] Reference Figures 1 to 4 According to the present disclosure, the method for improving the uniformity of the width of straight and oblique edges of a line comprises the following steps:

[0018] S1, provides two product sheets before the photolithography process;

[0019] S2, gluing, using the same gluing conditions to obtain two gluing sheets;

[0020] S3, exposure. The two coated sheets are exposed using a layout of a wafer composed of multiple distributed grains to obtain two exposed sheets. For the two coated sheets, different line widths are used at the connection position between the bevel edge and the adjacent straight edge. The bevel edge is connected to the adjacent straight edge via a tapered edge. The tapered edge serves as the connection position between the bevel edge and the adjacent straight edge. The remaining exposure parameters remain the same.

[0021] S4, developing, developing the two exposed films using the same developing conditions to obtain two developed films;

[0022] S5, select a grain, collect line widths in multiple areas of the selected grain, determine the influence of the line width at the connection position of the oblique edge and the adjacent straight edge on the line width uniformity of the connection position of the oblique edge and the adjacent straight edge in the grain and the straight edge not adjacent to the oblique edge, and determine the optimized parameters and optimized process for mass production of the lithography process.

[0023] In the method for improving the line width uniformity of straight edges and oblique edges of lines according to the present disclosure, the influence of the line width change at the connection position of the oblique edge and the adjacent straight edge in the layout design of the exposure process on the line width uniformity of the connection position of the oblique edge and the adjacent straight edge in the grain and the straight edge not adjacent to the oblique edge is analyzed. As verified by the test process, it can be clearly seen that the line width change at the connection position of the oblique edge and the adjacent straight edge in the layout design will affect the line width uniformity of the connection position of the oblique edge and the adjacent straight edge in the grain and the straight edge not adjacent to the oblique edge, thereby Improving the line width uniformity of the connection between the oblique edge and the adjacent straight edge and the straight edge not adjacent to the oblique edge (i.e., improving the line width uniformity between the straight edge and the oblique edge, or improving the line width uniformity within the grain) broadens the optimization direction and can determine the line width at the connection location of the oblique edge and the adjacent straight edge in the layout design during the exposure process to improve the line width uniformity of the connection location of the oblique edge and the adjacent straight edge and the straight edge not adjacent to the oblique edge (i.e., determining the optimization parameters for line width uniformity within the grain), thereby providing an optimized process for mass production of the lithography process. In addition, since only the line width at the connection location of the oblique edge and the adjacent straight edge in the layout design needs to be changed, there is no need to replace the machine for the exposure process in the lithography process, thereby saving the equipment cost of the lithography process.

[0024] Note that, if Figure 4 As shown, the line width at the connection position is the width between the inner and outer ends of the tapered edge away from the adjacent straight edge. In addition, in the structural design, an arc transition can be used between the tapered edge and the oblique edge.

[0025] As described in the test process, the line width uniformity of the connection position between the oblique edge and the adjacent straight edge and the straight edge not adjacent to the oblique edge is represented by the difference between the line width of the straight edge not adjacent to the oblique edge and the line width at the connection position between the oblique edge and the adjacent straight edge.

[0026] In step S1, in one example, each product sheet is surface-coated with Thick SIN film layer on an 8-inch diameter wafer. Of course, this is not limited to this. The surface conditions, dimensions, and quantity of each product wafer can vary based on actual production conditions. The number of product wafers can exceed two. This not only allows the determination of the line width value at the junction of the oblique edge of the layout design and the adjacent straight edge that satisfies the product's intra-die line width uniformity, but also allows the determination of the ultimate value at which intra-die line width uniformity is optimized.

[0027] In one example, the glue coating in step S2 includes the following sub-steps: S21, HMDS film formation, forming an HMDS film on the surface of each product sheet by a gas phase method; S22, cooling before glue coating, cooling each product sheet with an HMDS film formed on the surface in a cooling tank to the temperature required for glue coating; S23, coating, spin coating glue on each product sheet in a glue coating process tank; S24, pre-baking, pre-baking each product sheet after spin coating glue in a pre-baking process tank.

[0028] Specifically, in one example, in sub-step S21, the operation of forming the HMDS film by the gas phase method is as follows: each product sheet is placed on the wafer stage of the vacuum chamber and the wafer stage is heated to 110°C, nitrogen is used as the carrier gas and the nitrogen pressure is 25kPa, HMDS vapor carried by the nitrogen is introduced, the pressure of the vacuum chamber is maintained at 20Pa, the time of introducing the HMDS vapor carried by the nitrogen is 60s, and the thickness of the formed HMDS film is

[0029] Specifically, in one example, in sub-step S22, the temperature required for the coating is 23°C.

[0030] Specifically, in one example, in sub-step S23, the process of spin coating is as follows: 1.5 mL of glue solution is dripped to the center of each product sheet at 2050 rpm. After the glue solution is dripped for 1.5 seconds, each product sheet is rotated at 3180 rpm for 30 seconds. The final glue coating thickness is

[0031] Specifically, in one example, in sub-step S23 , the model of the glue is AR80-4CP.

[0032] Specifically, in one example, in sub-step S24 , the pre-baking temperature is 90° C. and the time is 60 seconds.

[0033] In one example, the exposure of step S3 includes the following sub-steps: S31, cooling before exposure, in which the two coated sheets after pre-baking are cooled in a cooling tank to the exposure temperature of 23°C; S32, exposure, in which the two coated sheets are respectively exposed using an I612-010-BE version with a layout design requirement of 250±25nm for straight edges and 0.27μm for the line width at the connection position between the oblique edge and the adjacent straight edge, and an I612-010-BF version with a layout design requirement of 250±25nm for straight edges and 0.30μm for the line width at the connection position between the oblique edge and the adjacent straight edge. Both versions are exposed using a Nikon SF120 machine with a stepper step of 12949μm in the X direction and 250389μm in the Y direction. The exposure dose for each stepper exposure is 290mj / cm 2 , the imaging focal length is 0.1 μm and the NA value is 0.62; S33, post-exposure baking, post-exposure baking is performed in a post-exposure baking process tank, the post-exposure baking temperature is 110° C., and the time is 120 s.

[0034] In one example, the development of step S4 includes the following sub-steps: S41, cooling before development, cooling each exposed film baked after exposure in a cooling tank to the temperature required for development, 23°C; S42, development, placing each exposed film cooled before development on the turntable of the developer, dripping developer to the center of each exposed film while rotating, and then flushing with water while rotating, the rotation is unidirectional, the rotation speed is 2000rpm, and a positive photoresist developer is used, the developer model is ZX-238, the development time is 60s, and the flushing time is 30s; S43, post-baking in a post-baking process tank, the post-baking temperature is 110°C, and the time is 90s.

[0035] In step S5, in one example, observing the line width uniformity of the connection position between the oblique edge and the adjacent straight edge and the straight edge not adjacent to the oblique edge is performed under a line width scanning electron microscope.

[0036] In step S5, the control Figure 1 In each display film, the corresponding grains can be selected as the objects of observation and collection in the center, upper, lower, left, and right edges, the middle row and middle column between the center and the upper, lower, left, and right edges of the display film. Figure 1 In the case shown, a total of 11 dies are selected from each display film for observation and collection of the line width of the critical dimension of interest in each die. Figure 3 The image is divided into nine equal line width collection areas. In each collection area, a pixel with a critical size at the center is selected as the representative. The number of pixels included in each grain is determined by the actual required resolution. For example, the pixels are arranged in a 640×512 matrix, with 640 pixels in each horizontal row and 512 pixels in each vertical column. For ease of explanation, Figure 2 Only some pixels of one grain are shown.

[0037] [test]

[0038] Example 1

[0039] The method for improving the uniformity of the width of straight and oblique edges of a line in Example 1 adopts the following steps:

[0040] S1, provide two product sheets before photolithography process, wherein each product sheet is coated with Thickness of SIN film layer on 8-inch diameter wafer;

[0041] S2, glue coating, glue coating under the same conditions to obtain two glue coated sheets,

[0042] The gluing in step S2 is performed using the following sub-steps:

[0043] S21, HMDS film formation, using a gas phase method to form an HMDS film on the surface of each product sheet. The operation of forming the HMDS film by the gas phase method is as follows: each product sheet is placed on the wafer stage of the vacuum chamber and the wafer stage is heated to 110°C. Nitrogen is used as the carrier gas and the nitrogen pressure is 25kPa. HMDS vapor carried by nitrogen is introduced. The pressure of the vacuum chamber is maintained at 20Pa. The time of introducing HMDS vapor carried by nitrogen is 60s. The thickness of the formed HMDS film is

[0044] S22, cooling before coating, each product sheet with the HMDS film formed on the surface is cooled in a cooling tank to the temperature required for coating, wherein the temperature required for coating is 23°C;

[0045] S23, coating, each product piece is spin-coated in the glue process tank, wherein the spin coating glue process is: drip 1.5mL glue solution to the center of each product piece at 2050rmp dynamic, after the glue solution drips 1.5s, rotate each product piece at 3180rpm for 30s, and the final glue coating thickness is The glue model is AR80-4CP;

[0046] S24, pre-baking, each product sheet after spin coating and coating is pre-baked in the pre-baking process tank,

[0047] Among them, the pre-baking temperature is 90℃ and the time is 60s;

[0048] S3, exposure. The two coated sheets are exposed using a layout of a wafer composed of multiple distributed grains to obtain two exposed sheets. For the two coated sheets, different line widths are used at the connection position between the bevel edge and the adjacent straight edge. The bevel edge is connected to the adjacent straight edge via a tapered edge. The tapered edge serves as the connection position between the bevel edge and the adjacent straight edge. The remaining exposure parameters remain the same.

[0049] The exposure in step S3 is performed using the following sub-steps:

[0050] S31, cooling before exposure, the two coated sheets after pre-baking are cooled in the cooling tank to

[0051] The temperature required for exposure is 23°C;

[0052] S32, exposure, for two coated films, respectively using the I612-010-BE version with a layout design straight edge line width of 250±25nm and a line width of 0.27μm at the connection position between the oblique edge and the adjacent straight edge, and the I612-010-BF version with a layout design straight edge line width of 250±25nm and a line width of 0.30μm at the connection position between the oblique edge and the adjacent straight edge. Both were exposed using a Nikon SF120 machine with a stepper X-direction of 12949μm and a stepper Y-direction of 250389μm. The exposure of each stepper exposure was 250μm.

[0053] The dose is 290 mj / cm 2 , the imaging focal length is 0.1 μm and the NA value is 0.62;

[0054] S33, post-exposure baking, post-exposure baking is performed in a post-exposure baking process tank, the post-exposure baking temperature is 110° C., and the time is 120 seconds.

[0055] S4, development, the two exposed films are developed under the same development conditions to obtain two developed films,

[0056] The development of step S4 adopts the following sub-steps:

[0057] S41, cooling before development, cooling each exposed piece baked after exposure in a cooling tank to the developing state

[0058] The temperature required for filming is 23℃;

[0059] S42, developing, placing each exposed film that has been cooled before development on a turntable of a developing machine, dripping developer onto the center of each exposed film while rotating, and then flushing with water while rotating. The rotation is unidirectional and the rotation speed is 2000 rpm. A positive photoresist developer (model ZX-238) is used. The developing time is 60 seconds and the flushing time is 30 seconds.

[0060] S43, post-baking in a post-baking process tank, the post-baking temperature is 110° C., and the time is 90 seconds;

[0061] S5, under a line width scanning electron microscope, select a crystal grain, collect line widths in multiple regions of the selected crystal grain, determine the influence of the line width at the connection position of the oblique edge and the adjacent straight edge on the line width uniformity of the connection position of the oblique edge and the adjacent straight edge within the crystal grain and the straight edge not adjacent to the oblique edge, and determine the optimized parameters and optimized process for mass production of the photolithography process;

[0062] In each display film, the corresponding grains in the center, upper, lower, left, and right edges, the middle row and middle column between the center and the upper, lower, left, and right edges are selected as the objects of observation and collection, such as Figure 1 As shown, a total of 11 grains are selected from each display film; for each grain, according to Figure 3The image is divided into nine line width collection areas in an equal way, and a key size of a pixel at the center is selected as the representative in each collection area.

[0063] For the two display sheets formed from the two product sheets, the 11 selected dies in each display sheet exhibited the same pattern of variation in the critical dimensions across the nine linewidth collection areas. Therefore, the die at the center of the wafer was used as a representative example. Furthermore, for the die at the center of the wafer, the critical dimensions exhibited the same pattern of variation across the nine linewidth collection areas. Therefore, the critical dimension of a single pixel at the center of one of the nine linewidth areas was used as a representative example for illustration.

[0064] Figure 5 The following is a photograph of the local morphology of the central pixel in the center of the nine regions of the selected wafer center when the line width at the connection position of the oblique edge and the adjacent straight edge is 0.27μm, the straight edge not adjacent to the oblique edge with the line width size marked, and the connection position of the oblique edge and the adjacent straight edge. Figure 5 It can be seen that the difference between the line width of the straight edge not adjacent to the oblique edge and the line width at the connection position between the oblique edge and the adjacent straight edge is 39.6 nm (ie, 243.6 nm-204.0 nm).

[0065] Figure 6 The following are photos of the local morphology of the central pixel in the center of the nine regions of the selected wafer center when the line width at the connection position of the oblique edge and the adjacent straight edge in the layout design is 0.30μm, as well as the straight edge not adjacent to the oblique edge and the connection position of the oblique edge and the adjacent straight edge marked with the line width size. Figure 6 It can be seen that the difference between the line width of the straight edge not adjacent to the oblique edge and the line width at the connection position between the oblique edge and the adjacent straight edge is 27.2 nm (ie, 229.8 nm-202.6 nm).

[0066] It can be seen that by increasing the line width at the connection position of the oblique edge and the adjacent straight edge of the layout design, the line width uniformity of the connection position of the oblique edge and the adjacent straight edge and the straight edge not adjacent to the oblique edge is improved (that is, the line width uniformity of the straight edge and the oblique edge is improved or the line width uniformity within the grain is improved). In other words, there is no need to replace the machine for the exposure process. Only the line width at the connection position of the oblique edge and the adjacent straight edge of the layout design needs to be adjusted to achieve the effect of improving the line width uniformity within the grain. In addition, when other process conditions remain unchanged, the line width of 0.30μm at the connection position of the oblique edge and the adjacent straight edge of the layout design can be used as the line width value at the connection position of the oblique edge and the adjacent straight edge of the exposure process of the batch production of the lithography process. In other words, for Example 1, the use of specific other process conditions and a line width of 0.30μm at the connection position of the oblique edge and the adjacent straight edge in the layout can be used as an optimized process for this product for batch production.

[0067] The above detailed description is used to describe a number of exemplary embodiments, but this document is not intended to be limited to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein may be combined to form multiple additional combinations that are not shown for the sake of brevity.

Claims

1. A method for improving the uniformity of the width of straight and oblique edges of a line, characterized in that: Including steps: S1, provides two product sheets before the photolithography process; S2, gluing, using the same gluing conditions to obtain two gluing sheets; S3, exposure. The two coated sheets are exposed using a layout of a wafer composed of multiple distributed grains to obtain two exposed sheets. For the two coated sheets, different line widths are used at the connection position between the bevel edge and the adjacent straight edge. The bevel edge is connected to the adjacent straight edge via a tapered edge. The tapered edge serves as the connection position between the bevel edge and the adjacent straight edge. The remaining exposure parameters remain the same. S4, developing, developing the two exposed films using the same developing conditions to obtain two developed films; S5, select a grain, collect line widths in multiple areas of the selected grain, determine the influence of the line width at the connection position of the oblique edge and the adjacent straight edge on the line width uniformity of the connection position of the oblique edge and the adjacent straight edge in the grain and the straight edge not adjacent to the oblique edge, and determine the optimized parameters and optimized process for mass production of the lithography process.

2. The method for improving the uniformity of the width of straight and oblique edges of a line according to claim 1, characterized in that: In step S1, each product sheet is surface-plated with Thickness of SIN film layer on 8-inch diameter wafer.

3. The method for improving the uniformity of the width of straight and oblique edges of a line according to claim 2, characterized in that: The gluing step S2 includes the following sub-steps: S21, HMDS film formation, forming an HMDS film on the surface of each product sheet by a vapor phase method; S22, cooling before coating, each product sheet with HMDS film formed on the surface is cooled in a cooling tank to the temperature required for coating; S23, coating, each product sheet is spin-coated in a coating process tank; S24, pre-baking, each product sheet after spin coating and leveling is pre-baked in a pre-baking process tank.

4. The method for improving the uniformity of the width of straight and oblique edges of a line according to claim 3, wherein: In sub-step S21, The operation of forming HMDS film by gas phase method is as follows: each product sheet is placed on the wafer stage of vacuum chamber and the wafer stage is heated to 110℃, nitrogen is used as carrier gas and the nitrogen pressure is 25kPa, HMDS vapor carried by nitrogen is introduced, the pressure of vacuum chamber is maintained at 20Pa, and the time of introducing HMDS vapor carried by nitrogen is 60s. The thickness of the formed HMDS film is 5. The method for improving the uniformity of the width of straight and oblique edges of a line according to claim 3, characterized in that: In sub-step S22, the temperature required for the coating is 23°C.

6. The method for improving the uniformity of the width of straight and oblique edges of a line according to claim 3, wherein: In sub-step S23, the process of spin coating is as follows: 1.5 mL of glue solution is dripped into the center of each product sheet at 2050 rpm. After the glue solution drips for 1.5 seconds, each product sheet is rotated at 3180 rpm for 30 seconds. The final glue coating thickness is In sub-step S23 , the model of the glue is AR80-4CP.

7. The method for improving the uniformity of the width of straight and oblique edges of a line according to claim 3, wherein: In sub-step S24, the pre-baking temperature is 90° C. and the time is 60 seconds.

8. The method for improving the uniformity of the width of straight and oblique edges of a line according to claim 1, wherein: The exposure of step S3 includes the following sub-steps: S31, cooling before exposure, the two coated sheets after pre-baking are cooled in a cooling tank to the required temperature of 23°C for exposure; S32, exposure. For two coated films, the I612-010-BE version, with a layout design requirement of 250±25nm straight edge line width and 0.27μm line width at the connection between the oblique edge and the adjacent straight edge, and the I612-010-BF version, with a layout design requirement of 250±25nm straight edge line width and 0.30μm line width at the connection between the oblique edge and the adjacent straight edge, were used. Both versions were exposed using a Nikon SF120 stepper machine, with a stepping distance of 12949μm in the X direction and 250389μm in the Y direction. The exposure dose for each stepping exposure was 290mj / cm 2 , the imaging focal length is 0.1 μm and the NA value is 0.62; S33, post-exposure baking, post-exposure baking is performed in a post-exposure baking process tank, the post-exposure baking temperature is 110° C., and the time is 120 seconds.

9. The method for improving the uniformity of the width of straight and oblique edges of a line according to claim 8, characterized in that: The development of step S4 includes the following sub-steps: S41, cooling before development, cooling each exposed sheet after post-exposure baking in a cooling tank to the temperature required for development, 23°C; S42, developing, placing each exposed film that has been cooled before development on a turntable of a developing machine, dripping developer onto the center of each exposed film while rotating, and then flushing with water while rotating. The rotation is unidirectional and the rotation speed is 2000 rpm. A positive photoresist developer (model ZX-238) is used. The developing time is 60 seconds and the flushing time is 30 seconds. S43, post-baking in a post-baking process tank, the post-baking temperature is 110° C., and the time is 90 seconds.

10. The method for improving the uniformity of the width of straight and oblique edges of a line according to claim 1, wherein: In step S5 , the line width uniformity of the connection position between the oblique edge and the adjacent straight edge and the straight edge not adjacent to the oblique edge is observed under a line width scanning electron microscope.

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