Patent ID: 6995091

Claim:
A process for chemically mechanically polishing wafers, which comprises: providing a CMP slurry having a solvent and at least one component being an interfering ion selected from the group consisting of inorganic salts and ceramic abrasives; defining a range of values for a level of the component in the CMP slurry; taking a slurry sample from the CMP slurry; with an electrothermal absorption spectrometer, performing electrothermal slurry atomic absorption spectrometry to obtain a determined level of the component in the slurry sample; comparing the determined level of the component with the range of values for the level of the component; if the determined level of the component is within the range of values for the level of the component, feeding the CMP slurry to a CMP device and polishing a wafer using the CMP slurry in the CMP device; and if the determined level of the component is outside the range of values for the level of the component, triggering a signal and feeding the CMP slurry to a temporary storage device.