Inclined lithography and photoresist optimization for fabrication of 3D mesh structures

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Journal Title
Journal ISSN
Volume Title
Sähkötekniikan korkeakoulu | Master's thesis
Date
2014-12-15
Department
Major/Subject
Micro and Nanotechnology
Mcode
S3010
Degree programme
EST - Master’s Programme in Micro and Nanotechnology
Language
en
Pages
80
Series
Abstract
The goal of this thesis was to fabricate 3D structures using SU-8 with a novel inclined exposure setup and process. The structures are 3D meshes whose final shape is dependent on both pattern on the photomask and SU-8 layer thickness. 3D structures were successfully fabricated on layers 100, 70 and 50 μm thick. Different patterns where tested to analyse the relations of the sizes and distribution of the holes in the mask with the final structures. SEM imaging confirmed the hypothesis that the shape of the 3D mesh is controlled by the pattern in the mask, the layer thickness and for a certain extent by the exposure dose. During the fabrication defects, caused by the behaviour of the resist during exposure, are observed in the structures. Most of the defects were eliminated or reduced in the optimized samples. The final structures fabricated had apertures in the mesh ranging from as small as 10 μm up to 40 μm and it was demonstrated that they can be fabricated inside microfluidic channels. Improvements to the process and potential applications are presented at the end of the thesis.
Description
Supervisor
Franssila, Sami
Thesis advisor
Jokinen, Ville
Keywords
microfabrication, inclined lithography, 3D structures, mesh, photoresist
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