Real-time curling probe monitoring of dielectric layer deposited on plasma chamber wall

Abstract

A microwave resonator probe called a curling probe (CP) was applied to in situ monitoring of a dielectric layer deposited on a chamber wall during plasma processing. The resonance frequency of the CP was analytically found to shift in proportion to the dielectric layer thickness; the proportionality constant was determined from a comparison with the finite-difference time-domain (FDTD) simulation result. Amorphous carbon layers deposited in acetylene inductively coupled plasma (ICP) discharge were monitored using the CP. The measured resonance frequency shift dictated the carbon layer thickness, which agreed with the results from the surface profiler and ellipsometry.

The curling probe: A numerical and experimental study. Application to the electron density measurements in an ECR plasma thruster

“…The CP700 O-Type has the best sensitivity, close to the employed HP (8.3 MHz/10 9 cm −3 ), allowing more precise measurements at lower densities. CP700 sensitivity is consistent with the CP ( f 0 ≈ 870 MHz) used by Hotta et al [20]: a density of 3x10 10 cm −3 induces a frequency shift of about ∆ f = 230 MHz. The temperature correction is efficient and it yields stable and consistent measurements when compared to the probes that are not affected by temperature changes, such as the HP or the CP O-Type, as can be seen in Figure 14.…”

“…The solid dielectric samples have a thickness of at least 10 mm. This necessity arises from the fact that the characteristic decaying length of the emitted EM field is a few mm [20].…”

“…Recently, the curling probe has been applied to the characterization of reactive plasmas for industrial processing [14,[19][20][21], where LP measurements were found to be difficult to use [19]. Time-resolved measurements of the electron density have been performed in a pulsed DC discharge in various gases under surface magnetic confinement [14].…”

“…Most recently, the group of Chubu University in Japan performed CP measurements to monitor the dielectric layer deposited during plasma processing in a 13.56 MHz RF inductive plasma discharge. Hotta et al [20] used a CP in the chamber wall of the reactor and measured a frequency shift of 230 MHz, corresponding to a density of approximately 2.9x10 10 cm −3 using the CP method proposed by Liang et al [15]. Ogawa et al [21] developed a technique to measure the thickness of the deposited film and the electron density simultaneously using two different-sized CPs.…”

Fabrication of an Optoplasmonic Raft with Improved SERS Performance Detecting Methamphetamine through Bubble Enrichment

“…43,44 According to the simulation results, if the dielectric shell geometry matches with the LSPR resonance frequency, the optical energy will be effectively converged, resulting in elevated Efield enhancement. 45 The E-field distribution of the optoplasmonic unit was estimated by FDTD, along with the optical flow depicted by the Poynting vector arrows (Figure 4). The dielectric shell in the optoplasmonic structure refracts the optical energy toward the metal NPs on the shell surface, resulting in an enhanced and expanded E-field intensity (Figure 4a,b).…”