Reduction of pad erosion

摘要

Improved technique of forming trench capacitors without causing excessive erosion at the edges of the array region resulting from polishing. The erosion is reduced by providing a block mask to protect the array region while partially removing a portion of the hard mask used to etch the trenches in the field region. The partial etch equalizes the height of the hard mask in the array and field region after formation of the deep trenches by a reactive ion etch.