Patent ID: 7851374

Claim:
A method of reclaiming a control wafer having a porous low-k dielectric layer deposited on a substrate wherein the low-k-dielectric layer contains a plurality of pores, the method comprising: etching the low-k dielectric layer by dipping the control wafer in a hydrofluoric acid-based etchant, the etchant comprising a dilating additive and a passivating additive; dilating the pores in the low-k dielectric using a dilating additive added to the etchant, wherein some of the pores connect to form a plurality of channels extending through the low-k dielectric layer; and forming a passivation layer between the low-k dielectric layer and the substrate using a passivating additive added to the etchant, wherein the etching of the low-k dielectric layer occurs concurrently with the dilation of the pores and the formation of the passivation layer, whereby the passivation layer protects the substrate from the etchant.