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:
Mar. 17, 2020
Filed:
Jul. 27, 2017
Tokyo Electron Limited, Tokyo, JP;
TOKYO ELECTRON LIMITED, Tokyo, JP;
Abstract
At a time point Twhen starting a process, a duty ratio of a high frequency power RFto which power modulation is performed is set to be an initial value (about 90%) which allows plasma to be ignited securely under any power modulating conditions. At the substantially same time of starting the process, the duty ratio of the high frequency power RFis gradually reduced from the initial value (about 90%) in a regular negative gradient or in a ramp waveform. At a time point tafter a lapse of a preset time T, the duty ratio has an originally set value Dfor an etching process. After the time point t, the duty ratio is fixed or maintained at the set value Duntil the end (time point T) of the process.