Patent ID: 8093070
Filing Date: 2012-01-10
Classification: H01L

Abstract:
1. A method comprising: forming a ferroelectric capacitor stack over a substrate; forming a patterned etch mask over the ferroelectric capacitor stack; etching at least a first portion of the ferroelectric capacitor stack to form a patterned ferroelectric capacitor stack, wherein the first portion includes a layer having a noble metal; ashing the patterned ferroelectric capacitor stack using at least oxygen, nitrogen, and water after the step of etching at least the first portion of the ferroelectric capacitor stack; performing a wet cleaning after the step of ashing the patterned ferroelectric capacitor stack using at least oxygen, nitrogen, and water; ashing the patterned ferroelectric capacitor stack at a temperate of at least 300° C. in an oxidizing ambient after the step of performing the wet cleaning; and etching at least a second portion of the ferroelectric capacitor stack after the step of ashing the patterned ferroelectric capacitor stack at the temperature of at least 300° C. in the oxidizing ambient.