CN-121995708-A - Method for improving line edge roughness of side wall of photoresist line

CN121995708ACN 121995708 ACN121995708 ACN 121995708ACN-121995708-A

Abstract

A method for improving line edge roughness of side walls of lines of photoresist comprises the steps of S1, providing two product sheets before a photoetching process, S2, gluing to obtain two Tu Jiaopian, wherein the glued photoresist is I-line glue, S3, exposing to obtain two exposure sheets, setting two PEB (post exposure baking) temperatures for the two exposure sheets, wherein the two PEB temperatures are different, and the rest exposure parameters are the same, S4, developing the two exposed sheets under the same developing condition to obtain two developing sheets, S5, carrying out SEM slicing on each developing sheet, observing the line edge roughness of the side walls, determining influence of the PEB temperature on the line edge roughness of the side walls, and determining optimization parameters and optimization processes of mass production of the photoetching process. Thereby, an improvement of line edge roughness of sidewalls of lines of photoresist can be achieved.

Inventors

SUN SHANSHAN
WANG YUE
ZHOU HONGYU
LI HAITAO

Assignees

安徽晶微科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260226

Claims (9)

1. A method of improving line edge roughness of sidewalls of lines of photoresist, comprising the steps of: S1, providing two product pieces before a photoetching process; S2, gluing to obtain two Tu Jiaopian pieces, wherein the glued photoresist is I-line photoresist; S3, exposing to obtain two exposure sheets, wherein two PEB (post exposure baking) temperatures are set for the two exposure sheets, the two PEB temperatures are different, and the other exposure parameters are the same; S4, developing, wherein the two exposed films after exposure are developed under the same developing condition to obtain two developed films; s5, carrying out SEM (scanning electron microscope) slicing on each developer, observing the line edge roughness of the side wall, determining the influence of PEB temperature on the line edge roughness of the side wall, and determining the optimization parameters and the optimization process of mass production of the photoetching process.
2. The method of improving line edge roughness of sidewalls of lines of photoresist as claimed in claim 1, In step S1, each product piece is an 8-inch diameter wafer with a 150A thick SIN film coated on the surface.
3. The method of improving line edge roughness of sidewalls of lines of photoresist as claimed in claim 2, The gluing of step S2 comprises the sub-steps of: s21, forming an HMDS film on the surface of each product piece in a gas phase mode; S22, cooling before spin coating, wherein each product piece with the HMDS film formed on the surface is cooled to the temperature required by spin coating in a cooling tank; s23, coating, namely spin coating the product pieces with spin coating glue in a glue coating process groove; S24, pre-baking, namely pre-baking each product piece after spin coating and glue homogenizing in a pre-baking process groove.
4. A method for improving line edge roughness of sidewalls of lines of photoresist as claimed in claim 3, In a sub-step S21, The operation of forming the HMDS film in a gas phase mode comprises the steps of placing each product sheet on a carrying table of a vacuum chamber, heating the carrying table to 110 ℃, taking nitrogen as carrier gas, introducing HMDS steam carried by the nitrogen at the pressure of 25kPa, keeping the pressure of the vacuum chamber at 20Pa, introducing the HMDS steam carried by the nitrogen for 60 seconds, and forming the HMDS film with the thickness of 6A.
5. A method for improving line edge roughness of sidewalls of lines of photoresist as claimed in claim 3, In sub-step S22, the temperature required for spin is 23 ℃.
6. A method for improving line edge roughness of sidewalls of lines of photoresist as claimed in claim 3, In the substep S23, the spin coating and gluing process is that 1.5mL of glue solution is dripped to the central position of each product piece in 2050rmp dynamic state, after the glue solution is dripped for 1.5S, each product piece is rotated for 30S at 3180rpm, and the final gluing thickness is 5350A; In sub-step S23, the glue model is AR80-3.3CP.
7. A method for improving line edge roughness of sidewalls of lines of photoresist as claimed in claim 3, In sub-step S24, the pre-bake temperature is 90 ℃ for 60S.
8. The method of improving line edge roughness of sidewalls of lines of photoresist as claimed in claim 2, The exposure of step S3 comprises the sub-steps of: s31, cooling before exposure, and cooling two glued sheets subjected to pre-baking after gluing in a cooling tank to the temperature of 23 ℃ required by exposure; S32, performing exposure by using a photomask and a Nikon SF120 machine, wherein the X direction of the step is 12949 mu m, the Y direction of the step is 250389 mu m, the exposure dose of each step exposure is 268mj/cm 2 , the imaging focal length is-0.4 mu m and the NA value is 0.62; And S33, performing post-exposure baking in a post-exposure baking process tank by adopting the PEB (post-exposure baking) temperature set in the step S3, wherein the PEB (post-exposure baking) temperatures of the two exposure sheets are 110 ℃ and 130 ℃ respectively, and the time is 120S.
9. The method of improving line edge roughness of sidewalls of lines of photoresist as claimed in claim 8, The development of step S4 includes the sub-steps of: S41, cooling before development, namely cooling two exposure sheets baked after exposure to the temperature of 23 ℃ required by development in a cooling tank; S42, developing, namely placing each exposure sheet cooled before developing on a rotary table of a developing machine, dripping developing solution to the center of each exposure sheet while rotating, flushing while rotating later, rotating to unidirectional rotation at a rotation speed of 2000rpm, adopting positive photoresist developing solution, wherein the model of the developing solution is ZX-238 type, and the developing time is 60S and the flushing time is 30S; S43, post-baking in a post-baking process tank, wherein the post-baking temperature is 110 ℃ and the post-baking time is 90S.

Description

Method for improving line edge roughness of side wall of photoresist line Technical Field The present disclosure relates to the field of semiconductors, and more particularly to a method of improving line edge roughness of sidewalls of lines of photoresist. Background In the process of manufacturing a semiconductor device, one of the important processes is a photolithography process, i.e., patterning a photoresist, followed by subsequent etching in accordance with the photolithography pattern. In lithographic patterns, the sidewall topography of the lines is required to be flat, i.e., line Edge Roughness (LER) is low. In the lithographic pattern, if the sidewall topography of the line is uneven, i.e., the verticality of the sidewall is poor (i.e., the sidewall forms a saw tooth in a direction perpendicular to the bottom surface of the line), such uneven topography of the sidewall of the line may affect not only the effective measurement of the line width dimension, but also the line width quality of the etching of the film layer under the lithographic pattern. Since the line edge roughness of the sidewalls of the lines in the lithographic pattern is affected in many ways, further intensive research is required to continuously widen the optimization direction for improving the line edge roughness of the sidewalls of the lithographic lines, providing optimization parameters and optimization processes for mass production of the lithographic process. Disclosure of Invention In view of the problems in the background art, an object of the present disclosure is to provide a method for improving line edge roughness of sidewalls of lines of photoresist, which can improve line edge roughness of sidewalls of lines of photoresist, can provide an optimized direction for improving line edge roughness of sidewalls of lines of photoresist, and can provide optimized parameters and an optimized process for mass production of photolithography process. It is another object of the present disclosure to provide a method of improving line edge roughness of sidewalls of lines of photoresist, which is capable of ensuring effective measurement of line width dimensions, and also ensuring line width quality of etching of a film layer under a lithographic pattern. The method for improving the line edge roughness of the side wall of the line of the photoresist comprises the steps of S1, providing two product pieces before a photoetching process, S2, gluing to obtain two Tu Jiaopian pieces, wherein the glued photoresist is I-line glue, S3, exposing to obtain two exposure pieces, setting two PEB (post exposure baking) temperatures for the two exposure pieces, wherein the two PEB temperatures are different, and the rest exposure parameters are the same, S4, developing the two exposed pieces under the same developing condition to obtain two developing pieces, S5, carrying out SEM slicing on each developing piece, observing the line edge roughness of the side wall, determining the influence of the PEB temperature on the line edge roughness of the side wall, and determining the optimization parameters and the optimization process of mass production of the photoetching process. The beneficial effects of the present disclosure are as follows. In the method for improving the line edge roughness of the sidewalls of the lines of photoresist according to the present disclosure, for the photoresist coated with the photoresist being an I-line photoresist, through the two different PEB temperatures of step S3, as verified by the test procedure, the effect of the PEB temperature on the line edge roughness of the sidewalls of the lines can be observed, thereby providing an optimized direction for improving the line edge roughness of the sidewalls of the lines of photoresist (i.e., improving the verticality of the sidewalls of the lines, in other words, making the sidewalls of the lines more flat in the direction perpendicular to the bottom surface of the lines), and providing optimized parameters and an optimized process for mass production of the photolithography process. In other words, by the method for improving the line edge roughness of the side wall of the line of the photoresist, the line edge roughness of the side wall of the line of the photoresist can be improved, an optimization direction can be provided for improving the line edge roughness of the side wall of the line of the photoresist, and optimization parameters and optimization processes can be provided for mass production of a photolithography process. In addition, by the method for improving the line edge roughness of the side wall of the line of the photoresist, effective measurement of the line width dimension can be ensured, and the line width quality of etching of the film layer below the photoetching pattern is ensured. Drawings Fig. 1 is a sidewall profile of lines of an SEM slice of one of the two product pieces of example 1 after completion of a photolithographic process at a