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:
Dec. 21, 2021
Filed:
Dec. 21, 2017
Texas Instruments Incorporated, Dallas, TX (US);
Elizabeth C. Stewart, Dallas, TX (US);
Jeffrey Alan West, Dallas, TX (US);
Thomas D. Bonifield, Dallas, TX (US);
Jay Sung Chun, Plano, TX (US);
Byron Lovell Williams, Plano, TX (US);
TEXAS INSTRUMENTS INCORPORATED, Dallas, TX (US);
Abstract
Methods of fabricating a thick oxide feature on a semiconductor wafer include forming a oxide layer having a thickness of at least six micrometers and depositing a photoresist layer on the oxide layer. The oxide layer has a first etch rate of X with a given etchant, the photoresist layer has a second etch rate of Y with the given etchant and the ratio of X:Y is less than 4:1. Prior to etching the photoresist layer and the oxide layer, the photoresist layer is patterned with a grayscale mask that creates a photoresist layer having a sidewall that forms an angle with the horizontal that is less than or equal to 10 degrees.