公开(公告)号：US11328900B2

公开(公告)日：2022-05-10

申请号：US16792562

申请日：2020-02-17

Applicant: Applied Materials, Inc.

Inventor： Teryl Pratt ,  Rongping Wang ,  Guomin Mao ,  Andy Chuang

IPC: H01J37/32 ,  H05H1/36

Abstract: A plasma ignition circuit includes a transformer having a primary coil configured to couple an RF power supply. A first secondary coil is configured to couple a remote plasma source (RPS), and a second secondary coil. The plasma ignition circuit further includes a control switch having an input configured to couple the second secondary coil and an output configured to capacitively couple the RPS and a switch controller. The switch controller is configured to upon sensing a secondary RF voltage applied to the second secondary coil in response to an RF voltage applied by RF power supply to the primary coil, enable the control switch to capacitively apply the secondary RF voltage to the RPS to ignite a plasma within the RPS. Upon sensing a drop in plasma impedance when the plasma is ignited, disable the control switch to discontinue applying the secondary RF voltage to the RPS.