Study of SU-8 photoresist cross-linking process by atomic force acoustic microscopy

Y Zhao; Y Liu; Z Wang; L Wang; L Li; F Hou; Z Song; Z Weng

doi:10.1111/jmi.12848

Study of SU-8 photoresist cross-linking process by atomic force acoustic microscopy

J Microsc. 2019 Dec;276(3):136-144. doi: 10.1111/jmi.12848. Epub 2019 Dec 2.

Authors

Y Zhao^{1

2}, Y Liu^{1

2}, Z Wang^{1

2

3}, L Wang^{1

2}, L Li^{1

2}, F Hou^{1

2}, Z Song^{1

2}, Z Weng^{1

2}

Affiliations

¹ Ministry of Education Key Laboratory for Cross-Scale Micro and Nano Manufacturing, Changchun University of Science and Technology, Changchun, China.
² International Research Centre for Nano Handling and Manufacturing of China, Changchun University of Science and Technology, Changchun, China.
³ JR3CN & IRAC, University of Bedfordshire, Luton, UK.

PMID: 31769508
DOI: 10.1111/jmi.12848

Abstract

In this paper, a method is presented to detect the different phases of epoxy cross-linking process and the subsurface structures of SU-8 thin films by atomic force acoustic microscopy (AFAM). The AFAM imaging of SU-8 thin films was investigated under different exposure and bake conditions. Optimized conditions were obtained for the cross-linking of SU-8 thin film at the exposure does of eight laser pulses with the laser fluence 10 mJ cm^-2 per pulse and the post exposure bake (PEB) time at 90 s. The subsurface structures of undeveloped SU-8 thin films were visible in the AFAM images. This method provides an effective and low-cost way for the determination of different phases of epoxy cross-linking process in nanostructured compounds, for the non-destructive testing of subsurface defects, and for the evaluation of the quality of patterned structures.

Keywords: Atomic force acoustic microscopy; Cross-linking process; SU-8; Subsurface imaging.

Publication types

Research Support, Non-U.S. Gov't