A SIMPLE OPTICAL SYSTEM TO OPTIMIZE A HIGH DEPTH TO WIDTH ASPECT RATIO APPLIED TO A POSITIVE PHOTORESIST LITHOGRAPHY PROCESS

摘要

The fabrication of micro electro mechanical systems by electrodeposition inside resist moulds has provided much interest in recent years. In this paper, we propose a method to optimize the lithography process of a thick positive photoresist. This technique is based on the variation of transparency of the photoresist during exposure. During exposure the absorption of the light-sensitive compound decreases due to its conversion into indene carboxylic acid. A very good aspect ratio (height:width) of up to 10:1 and high edge steepness (88 degrees) has been obtained from one coat and one UV exposure. [References: 9]