Optimization of 3D SU-8 microstructures using mask-less lithography and ultraviolet exposure

Maskless lithography has a broad prospect in fabricating 3D microstructures by negative photoresist SU-8, which is popular in MEMS and microfluidics application. Thus, in this dissertation project, I study the optimal UV exposure condition for the DMD-based maskless lithography and build some 3D mic...

Full description

Saved in:
Bibliographic Details
Main Author: Zhu, Junlei
Other Authors: Lee Seok Woo
Format: Thesis-Master by Coursework
Language:English
Published: Nanyang Technological University 2024
Subjects:
Online Access:https://hdl.handle.net/10356/179410
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
Description
Summary:Maskless lithography has a broad prospect in fabricating 3D microstructures by negative photoresist SU-8, which is popular in MEMS and microfluidics application. Thus, in this dissertation project, I study the optimal UV exposure condition for the DMD-based maskless lithography and build some 3D microstructures by SU-8 photoresist. For SU-8 3050 under 10x Lens, the optimal results are obtained at 60%intensity with 300s exposure time. For SU-8 3010 under 10x Lens, the optimal results are obtained at 50% intensity with 200s exposure time or 60% intensity with 300s exposure time. For SU-8 3050 under 20x Lens, the optimal results are obtained at 70% intensity with 100s exposure time. For SU-8 3010 under 20x Lens, the optimal results are obtained at 40% intensity with 400s exposure time. The 3D SU-8 microstructures can be fabricated by multi-exposure or shallow exposure methods. The former one is suitable for stacked patterns and the other one is suitable for bridge structures. A micromixer and several micro bridges are fabricated and evaluated by SEM.