Patent ID: 6593238
Filing Date: 2003-07-15
Classification: H01L

Abstract:
A method for determining an endpoint during chemical-mechanical polishing of a semiconductor wafer, comprising the steps of:providing the semiconductor wafer; depositing a first layer over the semiconductor wafer, wherein the first layer has a first portion on a second portion; depositing, on the first layer, a sacrificial layer, wherein the physical properties of the sacrificial layer are different from the physical properties of the first layer; polishing the semiconductor wafer to remove the sacrificial layer and the first portion of the first layer; and detecting a variation of the physical properties between the sacrificial layer and the first layer when polishing reaches the first layer; determining an endpoint on the basis of the variation; depositing a third layer on the sacrificial layer, wherein the physical properties of the sacrificial layer are different from the physical properties of the third layer; and removing the third layer during polishing.