Control over hydrogen fluoride levels in oxide etchant
AssigneeEcolab USA Inc.
InventorsAmy M. Tseng, Brian V. Jenkins, Robert Mack
Life of this patent
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Abstract
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.
Claims12
A method of detecting and measuring the presence of a free HF in a BOE composition, the method comprising the steps of:
- collecting a representative sample of a BOE composition,
- adding a chromogenic agent to the composition,
- performing a spectrometric measurement of the composition,
- comparing the spectrometric measurement to pre-determined values to identify the quantity of HF in the BOE composition.
A method of detecting and measuring the presence of a free HF in a BOE composition, the method comprising the steps of:
- collecting a representative sample of a BOE composition,
- adding a chromogenic agent to the composition,
- performing a spectrometric measurement of the composition,
- comparing the spectrometric measurement to pre-determined values to identify the quantity of HF in the BOE composition;
- wherein the measurement involves an SIA analysis of a sample of BOE liquid used in an etching process on a wafer substrate;
- and
- wherein the chromogenic agent is phenol red, chlorophenol red, thymol blue, bromocresol blue, rose Bengal, 4,5,6,7-Tetrachloro-2′,4′,5′,7′-tetraiodofluorescein disodium salt, and any combination thereof.
Dependencies are inferred from the claim text.