US 12,237,157 B2
Plasma measurement method
Eiki Kamata, Yamanashi (JP); Mikio Sato, Yamanashi (JP); Taro Ikeda, Yamanashi (JP); and Mitsutoshi Ashida, Yamanashi (JP)
Assigned to Tokyo Electron Limited, Tokyo (JP)
Filed by Tokyo Electron Limited, Tokyo (JP)
Filed on Aug. 23, 2022, as Appl. No. 17/893,621.
Claims priority of application No. 2021-142215 (JP), filed on Sep. 1, 2021.
Prior Publication US 2023/0066120 A1, Mar. 2, 2023
Int. Cl. H01J 37/32 (2006.01)
CPC H01J 37/32935 (2013.01) [H01J 37/32146 (2013.01); H01J 37/32926 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A plasma measurement method for measuring a plasma state using a probe device in the case of performing plasma processing on a substrate by introducing process gas into a processing container accommodating the substrate and by producing pulsed plasma using an electromagnetic wave pulse, wherein the electromagnetic wave pulse is obtained by processing an electromagnetic wave generated from an electromagnetic wave oscillator using a pulsing device, the method comprising:
Applying an AC voltage to the pulsed plasma using the probe device;
transmitting a signal from the pulsed plasma based on the AC voltage using the probe device and measuring data including a current value; and
obtaining a state of the pulsed plasma by analyzing the measured data;
wherein a frequency of the AC voltage is deviated from a frequency of the electromagnetic wave pulse so that the number of data required for the measurement of the pulsed plasma within one cycle of the electromagnetic wave pulse is obtained within allowable time,
wherein when the frequency of the AC voltage is fprobe and the frequency of the electromagnetic wave pulse is fpulse, the conditions shown in the following Eqs. (1), (2), and (3) are satisfied:

OG Complex Work Unit Math
wherein m and n represent a set of minimum positive integers satisfying the Eq. (1), and Tmax represents an upper limit of the allowable time for measuring the data.