title: Improved adhesion of gold thin films evaporated on polymer resin: applications for sensing surfaces and MEMS.
abstract: We present and analyze a method to improve the morphology and mechanical properties of gold thin films for use in optical sensors or other settings where good adhesion of gold to a substrate is of importance and where controlled topography/roughness is key. To improve the adhesion of thermally evaporated gold thin films, we introduce a gold deposition step on SU-8 photoresist prior to UV exposure but after the pre-bake step of SU-8 processing. Shrinkage and distribution of residual stresses, which occur during cross-linking of the SU-8 polymer layer in the post-exposure baking step, are responsible for the higher adhesion of the top gold film to the post-deposition cured SU-8 sublayer. The SU-8 underlayer can also be used to tune the resulting gold film morphology. Our promoter-free protocol is easily integrated with existing sensor microfabrication processes.
authors.affiliation: Department of Chemistry, Memorial University, St. John's, NL, Canada. bm3184@mun.ca
authors.forename: Behrang
authors.initials: B
authors.lastname: Moazzez
authors.forename: Stacey M
authors.initials: SM
authors.lastname: O'Brien
authors.forename: Erika F
authors.initials: EF
authors.lastname: Merschrod S
mesh_terms: D055119:Elastic Modulus; D006046:Gold / Q000737:chemistry*; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation / Q000379:methods*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation; D018625:Microscopy, Atomic Force; D011108:Polymers / Q000737:chemistry; D013499:Surface Properties
chemical_list: D011108:Polymers; D006046:Gold