Modular spectroscopy components are excellent tools for acquiring plasma emission spectra in real time from a plasma chamber. Plasma characteristics determined from these emission spectra can be used for monitoring and controlling plasma-based processes.
Plasma monitoring can be achieved with a flexible, modular setup using a spectrometer like our high-resolution HR4000 model or the UV-sensitive Maya2000 Pro, or with a fully integrated system like the PlasCalc plasma monitoring system. If quantitative measurements are desired for plasma control, the integrated PlasCalc system with its advanced process control systems and sophisticated data acquisition algorithms is your best option. Components for high-volume OEM applications are also available.
Fully integrated system for real-time, in situ analysis of optical emission spectra acquired during plasma processes.
Example Setup: Plasma Monitoring
Plasma is an energized, gas-like state where a fraction of the atoms have been excited or ionized to form free electrons and ions. Plasma is used in a range of applications including elemental analysis, film deposition, plasma etching and surface cleaning. By monitoring the emission spectrum of the sample plasma, we are able to determine critical plasma parameters required for controlling plasma-based processes. The wavelengths of the emission lines are used to identify the elements present in the plasma with emission line intensity used to quantify particle and electron densities in real time.
Plasma monitoring can be accomplished using a flexible, modular setup (as described here) or a fully integrated system such as the PlasCalc Plasma Monitoring system. For our example setup, we selected an HR2000+ high-resolution spectrometer configured with an HC-1 grating (200-1050 nm), 25 µm slit and variable longpass filter (DET2B-200-1100).
Your choice of sampling accessories depends on factors such as sampling position (inside or outside the vacuum) and chamber conditions. For in-vacuum applications, we offer both flange-type and O-ring vacuum feedthrough options and related accessories. In our example setup, we coupled a 400 µm solarization-resistant optical fiber (QP400-2-SR-BX) to a CC-3-UV-S cosine corrector, which is placed against the viewport of the plasma chamber. A large-diameter collimating lens like our COL-UV-30 is one of several alternatives to the cosine corrector.
OceanView spectroscopy software completes the system. Also available is SpecLine software, a program designed for identifying atomic emission lines and molecular bands in spectral data.
Plasma Monitoring System Components
|HR2000+||High-resolution spectrometer configured with an extended-range grating (200-1050 nm), 25 µm slit and variable longpass filter and quartz window (DET2B-200-1100)|
|CC-3-UV-S||Cosine corrector with Spectralon diffusing material; responsive from ~200-2500 nm|
|QP400-2-SR-BX||Premium-grade, solarization resistant optical fiber; 400 µm diameter, 2 m length, stainless steel BX jacketing|
|OceanView||Spectroscopy operating software|
Adding hydrogen gas to argon plasma changes its spectral properties.
Emission of argon plasma is measured through a vacuum chamber window.
Argon plasma emission is measured in the vacuum chamber before the addition of sheath gas.
With the addition of sheath gas, argon emission characteristics are noticeably different below 400 nm and at ~520 nm.