Patent ID: 6852017

Claim:
A method for removing material from a microelectronic substrate, comprising: providing a substrate holder that carries the microelectronic substrate and at least one membrane having a first membrane portion and a second membrane portion, the at least one membrane disposed between the substrate holder and the microelectronic substrate; engaging the microelectronic substrate with a planarizing medium; moving at least one of a first part of the microelectronic substrate and a first portion of the planarizing medium relative to the other at a first rate; moving at least one of a second part of the microelectronic substrate and the first portion of the planarizing medium relative to the other at a second rate less than the first rate; advancing the planarizing medium from a supply roller to a take up roller to engage a second portion of the planarizing medium with the first and second parts of the microelectronic substrate; and removing material from the first and second parts of the microelectronic substrate at approximately equal rates by biasing the first part of the microelectronic substrate against the planarizing medium with the first membrane portion having a first thickness and biasing the second part of the microelectronic substrate against the planarizing medium with the second membrane portion having a second thickness greater than the first thickness.