Sloping profile and pattern transfer to silicon by shape-controllable 3-D lithography and ICP

This paper describes a simple and effective method to fabricate various shapes and profiles of three-dimensional (3-D) silicon microstructures using a shape-controllable 3-D lithography along with dry plasma etching. The first step is to fabricate 3-D photoresist patterns with various slopes and round profiles on a silicon substrate by the shape-controllable 3-D lithography using polymer dispersed liquid crystal (PDLC) films, which is compatible to conventional lithography process. The second step is to transfer the sloping photoresist patterns into the silicon by etching 3-D photoresist molds and the silicon surface through inductively coupled plasma (ICP) process successively. The proposed microfabrication method for 3-D silicon microstructures can be widely applied for silicon lens arrays and silicon solar cells.