MAKING METHOD OF CONTACT HOLE

摘要

The contact for LSI device is prepared by forming a silicon oxide film on the exposed drain and source and gate electrode having a spacer oxide and mask oxide film, forming and reflowing BPSG silm thickly, cleaning it with NH4OH, etch-backing thinly, reforming a thick silicon oxide film, removing the upper silicon oxide film of the contact area, cleaning the BPSG film of the contact area with NH4OH, blanket etching the lower silicon oxide film to expose the drain, and the upper silicon oxide film of no contact area concurrently, depositing a bitline conductive film on all area, mask patterning the bitline connected with the drain.