Non-Plasma Dry Etcher Design for 200 mm-Diameter Silicon Carbide Wafer

Abstract

For improving the productivity of the semiconductor silicon carbide power devices, a very large diameter wafer process was studied, particularly for the non-plasma wafer etching using the chlorine trifluoride gas. Taking into account the motion of heavy gas, such as the chlorine trifluoride gas having the large molecular weight, the transport phenomena in the etching reactor were evaluated and designed using the computational fluid dynamics. The simple gas distributor design for a 200-mm-diameter wafer was evaluated in detail in order to uniformly spread the etchant gas over the wide wafer surface.

Chlorine Trifluoride Gas Etching Design for Quickly and Uniformly Removing a Thick C-Face 4H-Silicon Carbide Layer

“…9,12 In this study, the wafer rotation rate was fixed at 10 rpm. Because the wafer rotation at around 10 rpm takes the average of the etching rate along the concentric circle, 10,15 the window of the allowable and effective wafer rotation rate is very wide, probably those between 1 and several tens rpm.…”

“…In previous studies [9][10][11][12] for developing the dry etcher using the chlorine trifluoride gas, the local etching rate was shown to depend on the local chlorine trifluoride gas supply, similar to the chemical vapor deposition rate. 13 The gas distributor design [9][10][11][12] have been studied based on the theoretical calculations and experiments, in order to show the concept that the etching rate profile might be the average between different wavy etching rate profiles.…”