The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 01, 2020
Filed:
Apr. 05, 2019
Tokyo Electron Limited, Minato-ku, Tokyo, JP;
Antonio L. P. Rotondaro, Austin, TX (US);
Wallace P. Printz, Austin, TX (US);
Tokyo Electron Limited, Tokyo, JP;
Abstract
A technique to inhibit the growth of colloidal silica deposits on surfaces treated in phosphoric acid is described. In one embodiment, the disclosed techniques include the use of a colloidal silica growth inhibitor as an additive to a phosphoric acid solution utilized for a silicon nitride etch. In some embodiments, the additive may have chemistry that may contain strong anionic groups. A method and apparatus is provided that monitors the silica concentration and/or the colloidal silica growth inhibitor concentration in the phosphoric acid solution during processing and adjusts the amount of those components as needed. Techniques are provided for a method and apparatus to control the additive concentration to be used as well as the silica concentration in the phosphoric acid solution. The techniques described herein provide a high selectivity etch of silicon nitride towards silicon dioxide without the growth of colloidal silica deposits on the exposed surfaces.