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:
Feb. 01, 2022
Filed:
Feb. 08, 2019
Hitachi High-technologies Corporation, Tokyo, JP;
HITACHI HIGH-TECH CORPORATION, Tokyo, JP;
Abstract
In thickness/depth measurement of a wafer in etching, variation occurs in detected light quantity due to fluctuation of light quantity of a light source or fluctuation of air in a region through which light passes, and measurement accuracy of thickness/depth is reduced, and thus the total light quantity or average light quantity of an arbitrary wavelength is calculated from an optical spectrum measured at each time instant during etching, estimated total light quantity or estimated average light quantity at the present time, which is estimated using total light quantity or average light quantity measured prior to the present time, is calculated, a change rate, as a ratio of the total light quantity at the present time to the estimated total light quantity or a ratio of the average light quantity to the estimated average light quantity, is calculated, the calculated change rate is used to correct light quantity of each wavelength at the present time, and the corrected light quantity of each wavelength is used to perform thickness/depth measurement.