The effect of TFT lithography plane inclination on lithography pattern and improvement

Zhang Yuhu; Li Yawen; Luo Chuanwen; Li Li; Cao Shaobo; Ma Xiaohui

doi:10.12086/oee.2019.180679

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Zhang Yuhu, Li Yawen, Luo Chuanwen, et al. The effect of TFT lithography plane inclination on lithography pattern and improvement[J]. Opto-Electronic Engineering, 2019, 46(10): 180679. doi: 10.12086/oee.2019.180679

Citation:

Zhang Yuhu, Li Yawen, Luo Chuanwen, et al. The effect of TFT lithography plane inclination on lithography pattern and improvement[J]. Opto-Electronic Engineering, 2019, 46(10): 180679. doi: 10.12086/oee.2019.180679

The effect of TFT lithography plane inclination on lithography pattern and improvement

Hefei BOE Optoelectronics Technology Co. Ltd, Hefei, Anhui 230012, China

More Information

Corresponding author: Zhang Yuhu, E-mail: zhangyuhu@boe.com.cn

Received Date 22 December 2018

Revised Date 29 March 2019

Published Date 18 October 2019

Abstract

Abstract

In the lithography process of thin film transistor, the lithography plane position of photoresist is the key factor that determine the quality of lithography pattern. In order to improve the quality of lithography pattern under the minimum resolution of lithography machine, the reflection characteristic of the light in the photoresist is studied in this paper, based on reducing the intensity of the reflected light in the photoresist on the non-lithography region and increasing the intensity of the photoresist at the bottom on the lithography region, the computational formula for the lithography plane position adjustment of the photoresist is deduced under the oblique incidence. The adjustment amount is calculated by the formula and the lithography plane is adjusted by the adjustment. The results show that for the projection lithography machine with the minimum resolution of 3.0 μm, and for the product with the line space of 2.2 μm, after adjusting the lithography plane of photoresist with this adjustment, the slope angle of the lithography pattern is increased by 13.3%, and the uniformity of the DICD (development inspection critical dimension) is improved by 14.7%, the photoresist remain of the lithography pattern is resolved.
- lithography machine /
- resolution /
- oblique incidence /
- lithography plane /
- slope angle /
- lithography pattern

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References

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Overview

Overview

Overview: In the lithography process of thin film transistor (TFT), the DICD (develop inspection critical dimension) of the TFT affects the characteristics of TFT device, which is the key factor to determine the resolution of thin film transistor liquid crystal display (TFT-LCD) and the yield of driving. With the development of TFT-LCD, people's demand for the high-resolution display is increasing, but the high-resolution display requires TFT to have the small line width and narrow line space, which also determines the DICD formed by photolithography process to become smaller and smaller, so it will make the lithography machine tend to its minimum resolution when the lithography machine carries on the lithography craft. In actual production, in order to improve the resolution of lithography machine, the way of compensating and adjusting the focusing and leveling system of lithography plane is used, which makes the lithography plane of PR tend to the focus plane of lithography system, so as to achieve the goal of minimum resolution imaging. However, in actual production, due to continuous compensation, the actual adjustment margin is small and the improvement effect is limited. The adjustment is mainly compensated by the PR plane inclining, and the lithography light is no longer incident perpendicularly to the PR plane. As a result, the lithography light is inclined to the PR plane, which will lead to the enhancement of the lithography intensity in the non-lithography region caused by the reflection of PR, and the weakness of the lithography intensity on the surface of PR bottom, which will reduce the lithography machine's ability of the fine-line lithography at minimum resolution. In order to improve the quality of lithography pattern under the minimum resolution of lithography machine, the reflection characteristics of light in the photoresist is studied in this paper, based on reducing the intensity of the reflected light in the photoresist on the non-lithography region and increasing the intensity of the photoresist at the bottom on the lithography region, the computational formula for the lithography plane position adjustment of the photoresist is deduced under the oblique incidence. The adjustment amount is calculated by the formula and the lithography plane is adjusted by the adjustment. The results show that for the projection lithography machine with the minimum resolution of 3.0 μm and the product with the line space of 2.2 μm, after adjusting the lithography plane of photoresist with this adjustment, the slope angle of the lithography pattern is increased by 13.3%, and the uniformity of the DICD is improved by 14.7%, the photoresist remain of the lithography pattern is resolved.