Patent Number: 6,255,123

Title: Methods of monitoring and maintaining concentrations of selected species in solutions during semiconductor processing

Abstract: In one aspect, the invention encompasses a semiconductor processing method. A layer of material is provided over a substrate and reacted in a solution to remove at least some of the material. The reacting comprises a reaction chemistry that alters a concentration of a species in the solution. An absorbance of the solution is monitored for at least one wavelength of light that the species absorbs, and a concentration of the species in the solution is monitored by the monitoring of the absorbance. The concentration of the species in the solution is adjusted utilizing information obtained from the absorbance monitoring. In another aspect, the invention encompasses a semiconductor processing method wherein a layer of material is provided over a substrate and reacted with a solution to remove at least some of the material. The reaction consumes a component of the solution, and an absorbance of the solution is monitored for at least one wavelength of light that the consumed component absorbs. The concentration of consumed component in the solution is monitored during the reaction by monitoring the absorbance. The consumed component is added to the solution to maintain a substantially constant rate of reaction during the removal of the first material.

Inventors: Reis; Kenneth P. (San Antonio, TX)

Assignee:

International Classification: H01L 21/02 (20060101); H01L 21/311 (20060101); G01N 21/31 (20060101); G01N 21/35 (20060101); H01L 021/306 ()

Expiration Date: 07/03/2018