Numerical simulation and fabrication of microscale, multilevel, tapered mold inserts using UV-Lithographie, Galvanoformung, Abformung (LIGA) technology

Abstract

Techniques for economic fabrication of highaspect-ratio microscale structures (HARMS) are being investigated intensely. Microdevices employing metalbased HARMS are of particular interest for mechanical, electro-mechanical, and chemical applications. In many applications, HARMS with two or more heights are needed. Fabrication of these multi-level HARMS by compression molding requires two-level or multi-level mold inserts. In addition, tapered mold inserts would help achieving easy insert-part separation. This paper reports a process for fabricating two-level tapered mold inserts by combining UV-lithography of SU-8 resist, one-step metal electrodeposition, polish and level, followed by SU-8 resist removal. Without tilting and rotation during the lithography step, tapered plating molds are obtained by employing characteristics of UVlithography and resist development. The SU-8 removal method used does not reduce the strength of the electrodeposited mold insert. Efficacy of our approach is demonstrated with a two-level mold insert prototype.

A new UV lithography photoresist based on composite of EPON resins 165 and 154 for fabrication of high-aspect-ratio microstructures

“…6 shows two SEM images of some representative microstructures obtained using UV lithography of EPON resin 165 photoresist by following the foregoing processing steps. Our experiments have found that the lithography properties of EPON resin 165 photoresist are very close to those for SU-8 as published by our group [11,16,18,20,21,23,[26][27][28][29][30][31][32][33][34][35][36] and many other researchers [1][2][3][4][5][6][7][8][9][11][12][13][14][15][16][17][18][19]23,28,34,35,[37][38][39][40][41][42]. However, EPON resin 165 photoresist has a much shorter curing time.…”

“…However, EPON resin 165 photoresist has a much shorter curing time. The overall quality of the microstructures obtained seems also be very close to that obtained using SU-8 resist in our laboratory [11,16,18,20,21,23,[26][27][28][29][30][31][32][33][34][35][36].…”

“…However, there were no de-bonding problems between these types of microstructures and Si substrate in our experiments. With the different dosage ratio between i-line and h-line, the sidewalls with tapered angles can be obtained [32]. Our experiments have demonstrated that with the optimization of the dosage ratio between i-line and h-line, excellent vertical sidewall and sharp edges can be achieved as shown in Figs.…”

Fabrication and high-speed characterization of SU-8 shrouded two-dimensional microimpellers

“…Several kinds of multi-layer photolithography process using SU-8 were developed to fabricate microchannels, electroplating molds etc [10][11][12][13]. In this study, XP SU-8 3050 N-02 (hereinafter referred as 'SU-8 3000', Kayaku MicroChem), which is a new type of SU-8, was used.…”

Removal of SU-8 photoresist using buckling-driven delamination assisted with a carbon dioxide snow jet for microfluidics fabrication

“…SU-8 is a negative, near-UV photoresist which has been extensively utilized in the fabrication of micromechanical structures for MEMS applications since 1995 [1,2]. In the application of thick films with higher resolution, SU-8 has been utilized as a structural material for microfluidic systems, labon-a-chip, or as an electroplating mold [3,4]. SU-8 photoresist is a highly functional epoxy; as a result, it is extremely difficult to strip after it has been highly cross-linked.…”