Patent ID: 6025244
Filing Date: 2000-02-15
Classification: H01L

Abstract:
A method of forming a layer over an existing layer formed on a substrate with a pattern which is complementary and self-aligned to the pattern of the existing layer, the pattern of the existing layer having low portions spaced from the surface of the substrate by a first height and high portions spaced from the surface of the substrate by a second height which is greater than the first height, the difference between the first and second heights being denoted as a distance D, said method comprising the steps of:(a) forming a first layer of a first material over the existing layer such that said first layer substantially conforms to and reproduces the pattern of the existing layer and has high and low portions whose locations substantially correspond to the locations of the high and low portions respectively of the existing layer, the low portions of said first layer being below the high portions of said existing layer, said first material having a chemical composition different from that of the material of the existing layer;(b) forming a polish-stop layer of a second material over said first layer such that said polish-stop layer substantially conforms to and reproduces the pattern of said first layer and has high and low portions whose locations substantially correspond to the locations of the high and low portions respectively of the first layer, said second material having a chemical composition different from that of said first material; and(c) polishing the conformal first layer and polish-stop layer such that the high portions of said first layer and polish-stop layer are removed to expose the high portions of the existing layer, and such that the exposed pattern of the first layer which remains after the polishing step is self-aligned to the exposed pattern of the existing layer.