Aluminum-photoresist dual-layer lift-off process for gold micropattern preparation in cellular researches

With the development of microfabrication, micropatterns attract more and more attentions in cellular biology research. However, fabrication of micron annulus patterns with feature size of several micrometers by the traditional lift-off technique is still tricky. In this work, an aluminum-photoresist dual-layer lift-off process was developed to achieve a high yield and good reproducible gold micropattern with minimum feature size of 1.9 μm. The present method is proved to be prior to the traditional LOL-photoresist dual-layer lift-off process, especially when glass is used as the substrate, because the aluminum layer considerably increases the phase contrast between the photoresist and the substrate. To preliminarily validate the functionality of the present gold micropatterns in cellular research, a BSA-RBITC pattern with the protein just in the micro-well separated by the gold annulus is obtained.