Improved adhesion of gold thin films evaporated on polymer resin: applications for sensing surfaces and MEMS

Sensors (Basel). 2013 May 28;13(6):7021-32. doi: 10.3390/s130607021.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Elastic Modulus
  • Gold / chemistry*
  • Micro-Electrical-Mechanical Systems / instrumentation
  • Micro-Electrical-Mechanical Systems / methods*
  • Microfluidic Analytical Techniques / instrumentation
  • Microscopy, Atomic Force
  • Polymers / chemistry
  • Surface Properties

Substances

  • Polymers
  • Gold