Fabrication of high quality silicon mold by Cl2-based dry etching

초록

Imprint lithography is one of the technologies of low cost and mass production. In the imprint lithography, the shape of silicon mold is very important because performance of the replicated optical devices related to the shape of mold. Etched surface and sidewall roughness is heavy defect factor of optical devices. In conventional F-based silicon etching (so called Bosch process), F atoms react with Si spontaneously and they introduce isotropic etching cause undercutting below the mask. The Bosch process utilizes a multiplexed etch/passivation cycle that can alleviate this problem significantly. With Cl2 etching, many processes were developed for producing vertical sidewalls, smooth surface morphology and fine critical dimension control. The main advantage of Cl2 etching is that etching is anisotropic since it is an ion assisted process rather than a spontaneous etching process. Vertical profile can be easily obtained in Cl2 etching without polymer passivation or extensive water cooling. So in this paper, we attempt to Chlorine based etching and fabrication high quality silicon mold for minimize the loss after replication.