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Proceedings Paper

Effect of surface treatments/coatings and soft bake profile on surface uniformity and adhesion of SU-8 on a glass substrate
Author(s): Samantha Grist; Jasbir N. Patel; Moeed Haq; Bonnie L. Gray; Bozena Kaminska
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Paper Abstract

We present the effect of surface treatments/coatings and soft bake temperatures aimed at improving adhesion and surface uniformity of SU-8 on glass substrates. While the adhesion strength of SU-8 to metal layers on glass and silicon has been previously investigated, our research examines the influence of additional surface treatments (RCA, Acetone/IPA rinse) and coatings (fresh/one-day-aged Ti, fresh/one-day-aged Cr, SU-8 2005®) on adhesion strength as well as surface uniformity for 100 μm thick SU-8 films. Additionally, we vary the soft bake times and temperatures while keeping all other process parameters constant, to correlate adhesion strength with surface uniformity of SU-8 films for each surface modification. We have found that for all surface treatments/coatings, a soft bake temperature of 65°C for 90 minutes yielded a more uniform SU-8 film (σ = 5.18 μm) as compared to the manufacturer-recommended soft bake temperature of 95°C (σ = 12.66 μm) for 30 minutes. Consequently, a more uniform SU-8 film provided excellent adhesion strength (> 2 MPa, as determined by stress testing using an Instron® microtester) for both metallic seed layers while the adhesion strength of films baked at 95°C was determined to be < 0.5 MPa. This study, for the first time, has been able to quantitatively determine the adhesion strength of SU-8 films on different seed layers deposited on glass substrates, for varying soft bake temperatures.

Paper Details

Date Published: 12 February 2010
PDF: 10 pages
Proc. SPIE 7593, Microfluidics, BioMEMS, and Medical Microsystems VIII, 75930F (12 February 2010); doi: 10.1117/12.842957
Show Author Affiliations
Samantha Grist, Simon Fraser Univ. (Canada)
Jasbir N. Patel, Simon Fraser Univ. (Canada)
Moeed Haq, Simon Fraser Univ. (Canada)
Bonnie L. Gray, Simon Fraser Univ. (Canada)
Bozena Kaminska, Simon Fraser Univ. (Canada)

Published in SPIE Proceedings Vol. 7593:
Microfluidics, BioMEMS, and Medical Microsystems VIII
Holger Becker; Wanjun Wang, Editor(s)

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