Ecolab USA Inc.

Nalco Company

Robert M Mack

Brian V Jenkins

Amy M Tseng

A method of detecting and measuring the presence of ammonium fluoride in a buffered oxide etchant ('BOE') composition is provided. The method comprises contacting a BOE composition with a chromogenic agent selected from bromothymol blue, Eosin-Bluish, indophenol blue, bromocresol green, orthophthaldialdehyde, tetraphenylprophyrin, acridine orange, naphthalene-2,3-dicarboxaldehyde, 2-mercaptoethanol, n-acetylcysteine, luminal, bromocresol purple, or bromophenol blue and at least one of sodium hydroxide, ammonium nitrate, ammonium chloride, tartaric acid, octylphenoxypolyethoxyethanol, Triton X-100, borate buffer, sodium chloride, sodium tetra borate decahydrate, sodium sulfite, and Brij35 to form a treated BOE composition, the treated BOE composition having spectroscopic properties resulting from the contacting that correlate with the amount of ammonium fluoride in the treated BOE composition, performing a spectrometric measurement of the spectroscopic properties of the treated BOE composition, and comparing the spectrometric measurement to pre-determined values to identify the amount of ammonium fluoride in the BOE composition.

Control over etching molecule levels in etching compositions

The invention is directed towards methods and compositions for identifying the amount of hydrofluoric acid in a buffered oxide etching composition. In buffered oxide etching compositions it is very difficult to measure the amount of hydrofluoric acid because it has varying equilibriums and it is toxic so it hard to handle and sample. When used to manufacture microchips however, incorrect amounts of hydrofluoric acid will ruin those chips. The invention utilizes a unique method of spectrographically measuring the hydrofluoric acid when in contact with added chromogenic agents to obtain exact measurements that are accurate, immediate, and safe.

Control over hydrogen fluoride levels in oxide etchant

The invention is directed towards methods and compositions for identifying the amount of ammonium acid in a buffered oxide etching composition. In buffered oxide etching compositions it is very difficult to measure the amount of ammonium acid because it has varying equilibriums and it is toxic so it hard to handle and sample. When used to manufacture microchips however, incorrect amounts of ammonium acid will ruin those chips. The invention utilizes a unique method of spectrographically measuring the ammonium acid when in contact with added chromogenic agents to obtain exact measurements that are accurate, immediate, and safe.

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Milwaukie, OR, United States of America

Robert M Mack