METHODS OF FORMING CONTACT HOLES

摘要

Described is a method for forming contact holes, comprising the steps of: forming a stopper layer on a target layer having a cell area and an edge area surrounding the cell area; forming a hard mask having first upper openings and a dam trench on the stopper layer; forming opening spacers and a dam pattern for filling the dam trench on inner walls of the first upper openings; forming first lower openings for exposing the target layer by removing the stopper layer which is exposed within the first upper openings; forming an eave pattern on pillar patterns, which fill the first lower openings and the first upper openings, and the dam pattern; removing the hard mask within the cell area; forming first polymer blocks and second polymer blocks between the pillar patterns; forming second upper openings for exposing a surface of the stopper layer by removing the second polymer blocks; forming second lower openings by etching the stopper layer which is exposed within the second upper openings; and removing the first polymer blocks, the pillar patterns, the dam pattern, and the eave pattern. According various embodiments of the present invention, contact holes can be formed within the cell area while the contact holes are not formed within the edge area and/or peripheral areas.