EFFECT OF N-2 ADDITION ON ALUMINUM-ALLOY ETCHING BY ELECTRON-CYCLOTRON-RESONANCE REACTIVE ION ETCHING AND MAGNETICALLY ENHANCED REACTIVE ION ETCHING

Aluminum alloy etching is an important process in ultra-large-scale integration (ULSI) fabrication. We investigated the effect of N-2 addition to Cl-2 + BCl3 gas mixture on aluminum-copper alloy etching by electron cyclotron resonance reactive ion etching (ECR-RIE) and magnetically enhanced reactive ion etching (MERIE). In ECR-RIE, N-2 addition was effective in suppressing residues and post-etch corrosion of aluminum alloy interconnects; on the other hand, in MERIE, N-2 addition promoted the formation of residues and post-etch corrosion. This difference is probably caused by BClX+ in plasma, because it was found by mass spectral analysis that N-2 addition increased the amount of BClX+ in plasma of ECR-RIE, but it decreased that in plasma of MERIE.