CN-119781260-B - Method for obtaining high-resolution graph by utilizing different illumination modes

CN119781260BCN 119781260 BCN119781260 BCN 119781260BCN-119781260-B

Abstract

The present disclosure provides a method for obtaining high resolution patterns using different illumination modes, relating to the field of lithography technology, the method comprising forming a negative photosensitive film layer, a positive photosensitive film layer and a metal reinforcing layer laminated in sequence on a substrate; the method comprises the steps of adopting a first illumination mode, exposing a positive photosensitive film layer based on a mask, adopting a second illumination mode, exposing a negative photosensitive film layer based on the mask, enabling illumination wavelengths of the first illumination mode and the second illumination mode to be the same, enabling a first focal depth of the first illumination mode to be different from a second focal depth of the second illumination mode, developing the exposed positive photosensitive film layer and the exposed negative photosensitive film layer in sequence to obtain a pattern structure generated by the two exposures, and transferring the pattern structure generated by the two exposures to a substrate to obtain a high-resolution pattern.

Inventors

LUO XIANGANG
LUO YUNFEI
LIU KAIPENG
ZHANG YIYIN
ZHU YAOYAO
GUO TAO
ZHAO ZEYU

Assignees

中国科学院光电技术研究所

Dates

Publication Date: 20260512
Application Date: 20250313

Claims (7)

1. A method for obtaining a high resolution image using different illumination modes, comprising: Forming at least a negative photosensitive film layer, a positive photosensitive film layer and a metal reinforcing layer which are sequentially stacked on a substrate, wherein the negative photosensitive film layer is close to the substrate; The method comprises the steps of adopting a first illumination mode, exposing the positive photosensitive film layer based on a mask plate, adopting a second illumination mode, exposing the negative photosensitive film layer based on the mask plate, wherein the first illumination mode comprises normal incidence illumination, the second illumination mode comprises off-axis illumination, the illumination wavelength of the first illumination mode is the same as that of the second illumination mode, the first focal depth of the first illumination mode is smaller than that of the second illumination mode, the illumination wavelength of the first illumination mode and the illumination wavelength of the second illumination mode comprise one of 365 nm, 248 nm, 193 nm and 13.5 nm, the mask pattern height of the mask plate is 30-50 nm, the period of the mask pattern is 40-300 nm, the duty ratio of the mask pattern is 3:1-1:1, and the critical dimension of the mask pattern is 20-150 nm; The exposure dose of the normal incidence illumination is 20 mJ/cm 2 -200 mJ/cm 2 , and the slit width of the pattern structure on the positive photosensitive film layer is larger than half of the period of the mask pattern; The illumination angle of the off-axis illumination is 5-90 degrees, the exposure dose of the off-axis illumination is 50 mJ/cm 2 -300 mJ/cm 2 , the line width of a pattern structure on the negative photosensitive film layer is less than half of the period of the mask pattern, and the pattern structure on the negative photosensitive film layer is opposite to the mask pattern structure of the mask plate; Developing the exposed positive photosensitive film layer and the exposed negative photosensitive film layer in sequence to obtain a pattern structure generated by two times of exposure; and transferring the pattern structure generated by the two exposures to the substrate to obtain a high-resolution pattern.
2. The method of claim 1, wherein the negative photosensitive film layer and the positive photosensitive film layer are prepared by a coating, spraying, or fumigation method; The positive photosensitive film layer comprises at least one of AR series photoresist, AZ series photoresist and PHS photoresist; The thickness of the positive photosensitive film layer is 20 nm-50 nm; The negative photosensitive film layer is made of at least one of SU-8 photoresist and polyester photoresist, and has a thickness of 50-1000 nm.
3. The method of claim 1, wherein the metal reinforcement layer is prepared by thermal evaporation, electron beam evaporation, magnetron sputtering deposition, chemical vapor deposition, or coating.
4. The method of claim 1, wherein the light blocking layer material of the reticle comprises at least one of chromium, silicon, molybdenum.
5. The method of claim 1, wherein developing the exposed positive-tone photosensitive film layer and the exposed negative-tone photosensitive film layer in that order comprises: developing the positive photosensitive film layer by adopting a positive developing solution, wherein the positive developing solution comprises at least one of TMAH developing solution and NAOH developing solution; And developing the negative photosensitive film layer by adopting a negative developing solution, wherein the negative developing solution comprises at least one of n-butyl acetate developing solution, 3-ethoxypropionic acid ethyl ester developing solution and 2-heptanone developing solution.
6. The method of claim 1, wherein transferring the pattern structures created by the two exposures onto the substrate comprises: and adopting ion beam etching, reactive ion etching or inductively coupled plasma etching to transfer the pattern structure generated by the two exposures to the substrate.
7. The method of claim 1, wherein the substrate comprises a transparent substrate or an opaque substrate; the transparent substrate includes a glass substrate or a sapphire substrate; The opaque substrate comprises a silicon substrate.

Description

Method for obtaining high-resolution graph by utilizing different illumination modes Technical Field The present disclosure relates to the field of photolithography, and more particularly, to a method for obtaining a high resolution pattern using different illumination modes. Background The gate pattern is one of the key layers of the microelectronic device, and its characteristic dimension directly represents the processing node of the nano lithography technology, wherein the preparation of the high-resolution gate is gradually becoming a research hotspot in the field of semiconductor devices. Various resolution enhancement techniques have been developed when the gate feature size is less than 50 nm, wherein the double exposure technique finds a great deal of application in the processing of critical layers of semiconductor devices. The double exposure technology splits the same critical layer pattern on two mask plates, and performs double exposure by using precise alignment, thereby realizing the processing of the gate critical layer pattern with smaller characteristic size. However, as feature sizes further decrease, double exposure places increasing demands on alignment accuracy, which presents a greater challenge to precision alignment techniques. Disclosure of Invention In view of the above, the embodiment of the disclosure provides a method for obtaining a high-resolution pattern by using different illumination modes, which comprises forming at least a negative photosensitive film layer, a positive photosensitive film layer and a metal reinforcing layer which are sequentially stacked on a substrate, exposing the positive photosensitive film layer by using a first illumination mode based on a mask, exposing the negative photosensitive film layer by using a second illumination mode based on the mask, exposing the first illumination mode with the same illumination wavelength as the second illumination mode, developing the exposed positive photosensitive film layer and the exposed negative photosensitive film layer with different first focal depth from the second illumination mode to obtain a pattern structure generated by the two exposures, and transferring the pattern structure generated by the two exposures to the substrate to obtain the high-resolution pattern. According to an embodiment of the present disclosure, the first illumination mode comprises normal incidence illumination, the second illumination mode comprises off-axis illumination, the illumination wavelengths of the first illumination mode and the second illumination mode comprise one of 365 nm, 248 nm, 193 nm, 13.5 nm, and the first depth of focus is less than the second depth of focus. According to embodiments of the present disclosure, a coating, spraying, or fumigation method is used to prepare a negative photosensitive film layer and a positive photosensitive film layer; the positive photosensitive film layer comprises at least one of AR series photoresist, XT series photoresist and PHS photoresist, the thickness of the positive photosensitive film layer is 20-50 nm, the negative photosensitive film layer comprises at least one of PMMA photoresist, SU-8 photoresist and polyester photoresist, and the thickness of the negative photosensitive film layer is 50-1000 nm. According to embodiments of the present disclosure, the metal reinforcement layer is prepared by thermal evaporation, electron beam evaporation, magnetron sputtering deposition, chemical vapor deposition or coating, and the material of the metal reinforcement layer includes an excited surface plasmon material. According to the embodiment of the disclosure, the material of the light blocking layer of the mask comprises at least one of chromium, silicon and molybdenum, the height of the mask pattern of the mask is 30-50 nm, the period of the mask pattern is 40-300 nm, the duty ratio of the mask pattern is 3:1-1:1, and the critical dimension of the mask pattern is 20-150 nm. According to embodiments of the present disclosure, the exposure dose for normal incidence illumination is 20 mJ/cm 2-200 mJ/cm2, and the slit width of the pattern structure on the positive photosensitive film layer is greater than half the period of the mask pattern. According to the embodiment of the disclosure, the off-axis illumination has an illumination angle of 5-90 degrees, the exposure dose of the off-axis illumination is 50 mJ/cm 2-300 mJ/cm2, the line width of the pattern structure on the negative photosensitive film layer is less than half of the period of the mask pattern, and the pattern structure on the negative photosensitive film layer is opposite to the mask pattern structure of the mask plate. According to the embodiment of the disclosure, the positive photosensitive film layer after exposure and the negative photosensitive film layer after exposure are developed, wherein the positive photosensitive film layer is developed by adopting a positive developing solution, the positive develo