Large-Scale Etching of Silicon Nitride Using a Linear ECR Plasma Source with Reciprocating Substrate Motion

We have etched 700 nm thick silicon nitride (SiNx) on 370×235 mm2 substrate using a linear electron cyclotron resonance (ECR) plasma source with reciprocating substrate motion. A mixture of NF3 and Ar gases was used as etch gas. The etching of SiN x was performed with and without reciprocating substrate motion and compared to each other. In the etching without reciprocating substrate motion, the etch rate was measured in 45 points, showed 17.5% uniformity and the average etch rate was 92 nm/min. For the etching with reciprocating substrate motion, 4% uniformity of etch rate and 72 nm/min etch rate were obtained in the same measuring points. Moreover, there were no stains left on 370×235 mm2 SiNx glass after the etching with reciprocating substrate motion. In this paper, the linear ECR plasma source with reciprocating substrate motion is proved to be suitable for large-sized substrates and is profitable due to high yield and low-cost manufacturing.