Patent ID: 7517796

Claim:
A method for forming a reduced CD pillar, the method comprising: forming a conductor rail above a substrate, the conductor rail having a rail width; forming a layer of etchable material above the conductor rail; forming a layer of photoresist over the etchable material; patterning and developing the photoresist layer to form a photoresist pillar having no cross-section width in any direction which is more than three times the cross-section width in any other direction, the photoresist pillar having a first width no larger than about 0.3 micron and having a first aspect ratio, wherein the photoresist pillar is adapted to survive mechanical stresses encountered during a wash-and-spin process, and wherein the first width is larger than the rail width; spraying the photoresist layer with deionized water to stop the developing; spinning the substrate to remove the deionized water; shrinking the photoresist pillar to a second width smaller than the first width to form a shrunken photoresist pillar while controlling isotropy during the shrinking step by using an O 2 based etch and adjusting the O 2 percentage used to control isotropy, wherein the shrunken photoresist pillar has a second aspect ratio greater than the first aspect ratio, and wherein the second width is substantially equal to the rail width; and etching the etchable material to form an etched pillar, wherein the etched pillar is substantially aligned with the conductor rail and has a pillar width substantially equal to the rail width.