ALEXANDRIA, Va., June 19 -- United States Patent no. 12,334,309, issued on June 17, was assigned to Tokyo Electron Ltd. (Tokyo).
"Filter device and plasma processing apparatus" was invented by Naohiko Okunishi (Miyagi, Japan) and Nozomu Nagashima (Miyagi, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "Provided is a filter device includes: a first coil group including a plurality of coils arranged along a central axis and spirally wound with a first inner diameter; and a second coil group including a plurality of coils arranged along the central axis and spirally wound with a second inner diameter larger than the first inner diameter. A pitch between respective turns of the plurality of coils of the sec...