High-Rate and High-Selectivity Liquid Crystal Display Process with A Large Size Surface Wave Plasma Source Using a Slot Antenna

Abstract

A stable and uniform large-area plasma source for a 400 × 500 mm² size glass substrate using surface waves generated from a slot antenna has been developed. The width of the slot antenna was changed in five stages and two waveguides with two slot antennas were arranging in parallel. Ar plasma electron density of the order of 10¹¹ cm^-3 was investigated. As a result of process evaluation, a poly-Si etching rate of 470 nm/min and a SiNx etching rate of 770 nm/min were obtained. These values are approximately twofold to fivefold the corresponding values obtained by conventional chemical dry etching. The ashing rate of 1300 nm/min was sufficient for practical application. The selectivity to SiNx was 100 or more by the addition of CHF₃gas. This is considered to be because the ammonium salt deposited on the SiNx surface formed a protective layer.