A simple optical system to optimize a high depth to width aspect ratio applied to a positive photoresist lithography process

Abstract

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 • ) has been obtained from one coat and one UV exposure.

Process and realization of a three-dimensional gold electroplated antenna on a flexible epoxy film for wireless micromotion system

“…19 Thus, exposure dose increases drastically with resist thickness. 19 Thus, exposure dose increases drastically with resist thickness.…”

Silicon Micromachining for High Performance Passive Structures at W Band

“…Reliability tests have been carried out through pressure steps and thermal cycles on membrane featuring areas of 4 mm 2 , 8 mm 2 and 12 mm 2 . We have observed no failure with pressure steps up to 1 bar and several hundred thermal cycles ranging from À30 C to 150 C. Concerning the microwave section, we have developed a technological process allowing an accurate control of the circuit size and a minimization of the ohmic losses [2]. The process derives from the well known LIGA one [3,4].…”

Potentialities of a new positive photoresist for the realization of thick moulds

“…Several curves can be drawn according to prebake conditions, exposure time and thickness [1]. These parameters, for a given thickness, have been optimized to give better transparency.…”