Effects of O/sub 2//C/sub 2/F/sub 6/ plasma descum with RF cleaning on via formation in MCM-D substrate using photosensitive BCB

Abstract

In this paper, we present the effect of plasma descum by O/sub 2//C/sub 2/F/sub 6/ gas mixture on the via formation of photosensitive BCB layer and compare it with that of RF cleaning. Test vehicle was fabricated on Si wafer with Cu/photosensitive BCB layer structure and ECR-CVD system was used to descum the via. Residues at via bottom after the descum process were investigated by AES (auger electron microscope) and SEM (scanning electron microscope). It is shown in this work that O/sub 2//C/sub 2/F/sub 6/ plasma etching and the RF cleaning are effective for organic C, native C respectively, therefore the via descum by a combination of plasma etching with O/sub 2//C/sub 2/F/sub 6/ gas mixture and RF cleaning can efficiently remove the via residues.