High-purity fluorinated hydrocarbon, use as a plasma etching gas, and plasma etching method

Patent metadata

Field	Value
Publication number	US-9984896-B2
Application number	US-201415033457-A
Country	US
Kind code	B2
Filing date	Oct 28, 2014
Priority date	Oct 30, 2013
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

The present invention is a fluorohydrocarbon represented by R—F wherein R represents an isobutyl group or a t-butyl group), the fluorohydrocarbon having a purity of 99.9% by volume or more and a total butenes content of 1,000 ppm by volume or less; a use of the fluorohydrocarbon as a plasma etching gas; and a plasma etching method comprising selectively subjecting an inorganic nitride film stacked on silicon or a silicon oxide film to plasma etching using the fluorohydrocarbon.

First claim

The invention claimed is:

1. A plasma etching method comprising selectively subjecting an inorganic nitride film stacked on silicon or a silicon oxide film to plasma etching using a fluorohydrocarbon represented by R—F (wherein R represents an isobutyl group), the fluorohydrocarbon having a purity of 99.9% by volume or more, the fluorohydrocarbon comprising: a total butenes content from 414 ppm to 1,000 ppm by volume; a nitrogen content of 100 ppm by volume or less; and an oxygen content of 50 ppm by volume or less as a plasma etching gas,
wherein the fluorohydrocarbon has been prepared by fluorinating isobutanol by using a fluorinating agent or by treating isobutyl bromide or an isobutyl alkylsulfonate with an alkali metal fluoride, followed by distillation.

2. The plasma etching method according to claim 1 , wherein a selectivity ratio of the nitride film over the silicon oxide film is infinity.

3. A plasma etching method comprising selectively subjecting an inorganic nitride film stacked on silicon or a silicon oxide film to plasma etching using a fluorohydrocarbon represented by R—F (wherein R represents a t-butyl group), the fluorohydrocarbon having a purity of 99.9% by volume or more, the fluorohydrocarbon comprising: a total butenes content from 414 ppm to 1,000 ppm by volume; a nitrogen content of 100 ppm by volume or less; and an oxygen content of 50 ppm by volume or less as a plasma etching gas,
wherein the fluorohydrocarbon has been prepared by treating t-butanol with an amine complex of a hydrofluoric acid or a hydrogen fluoride, followed by distillation.

4. The plasma etching method according to claim 3 , wherein a selectivity ratio of the nitride film over the silicon oxide film is infinity.

Assignees

• Zeon Corp

Inventors

• Sugimoto Tatsuya

Classifications

• H10P95/00

  Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass · CPC title

• H10P50/283

  by chemical means · CPC title

• H10P50/267

  using plasmas · CPC title

• H10P50/242

  of Group IV materials · CPC title

• H10P50/28

  of insulating materials · CPC title