Patent ID: 7094687

Claim:
A method of forming via structures between a first electrically conductive layer and a second electrically conductive layer, the method comprising the sequential steps of: forming the first electrically conductive layer, forming a dielectric layer over the first electrically conductive layer, forming a first photoresist layer over the dielectric layer, patterning the first photoresist layer with a first via hole pattern that includes via holes that are all disposed within a first distance one from another, called dense via holes, and excludes via holes that are disposed at greater than the first distance one from another, called isolated via holes, etching the dense via holes into the dielectric layer at first etch conditions until the dense via holes are properly formed, removing the first photoresist layer, forming a second photoresist layer over the dielectric layer, patterning the second photoresist layer with a second via hole pattern that excludes dense via holes, and includes isolated via holes, etching the isolated via holes into the dielectric layer at second etch conditions until the isolated via holes are properly formed, wherein the first etch conditions are different from the second etch conditions, removing the second photoresist layer, forming electrically conductive vias within both the dense via holes and the isolated via holes, and forming the second electrically conductive layer over the dielectric layer, where electrical continuity exists between the first electrically conductive layer and the second electrically conductive layer through the electrically conductive vias.