ALEXANDRIA, Va., Aug. 6 -- United States Patent no. 12,381,071, issued on Aug. 5, was assigned to Hitachi High-Tech Corp. (Tokyo).
"Plasma processing method and plasma processing apparatus" was invented by Mitsuru Nagasawa (Tokyo), Soichiro Eto (Tokyo), Tatehito Usui (Tokyo) and Shigeru Nakamoto (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "A process of detecting a thickness of a film layer to be processed or a depth of etching by using a result of detection of a signal indicating intensity of interference light having a plurality of wavelengths formed by being reflected on a surface of a wafer at a plurality of time instants from when plasma is formed to when the etching is completed. A start time i...