Method for patterning photoresist pillars using a photomask having a plurality of chromeless nonprinting phase shifting windows

摘要

A method for patterning a photoresist using a photomask to form an integrated circuit, the photomask including a first area transmitting light in a first phase surrounded by a second area, the second area transmitting light in a second phase, the second phase opposite the first phase. No blocking material separates the first area from the second area. After development of the photoresist, the transition along a perimeter between the first and the second area causes formation of a residual photoresist feature on the photoresist surface due to phase canceling of light. If the first area is small enough, it is nonprinting, i.e., the opposite sides of the residual photoresist feature formed at its perimeter merge, forming a contiguous photoresist feature, such as a pillar, and thus a corresponding patterned feature or pillar after etching (e.g., to form a portion of a memory cell, etc.).