EM-KLEEN and SEMI-KLEEN downstream plasma cleaner
Surface contaminations especially the carbonaceous contamination have been a headache for many thin film deposition and surface analysis systems such as ALD, SIMS and XPS systems. When samples are exposed to air for 1 hour, the top surface layer of the samples will be coated with a layer of hydrocarbon contamination. Donwstream plasma cleaning techniques utilize a remote plasma cleaner attached to the loadlock chamber or the deposition/analysis chamber to generate radical species containing oxygen, hydrogen or even fluorine to remove carbonaceous and oxide surface contaminations.
EM-KLEEN and SEMI-KLEEN remote plasma cleaner utilizes electrode-less inductively coupled plasma discharge technology to avoid metal sputtering issue on other types of plasma sources. Proprietary plasma source design reduces plasma potential, which determines the energy of ions that drift out of the plasma sheath. EM-KLEEN and SEMI-KLEEN plasma source have been demonstrate to be able to clean sample surface without ion sputtering damaging on the top surface layer. The key to achieve ultra-clean non-damaging surface contamination removal is to build a plasma source with very low plasma potential and to select chamber materials that can resist chemical attack from radical species generated in the plasma. SEMI-KLEEN sapphrie is equiped with sapphire plasma tube and chemical resistant vacuum seal, It can support aggressive and sometimes corrosive plasma such as NF3, CF4, H2S, HF and NH3.
Low pressure discharge technique improves the cleaning rate for process gases such as H2 due to lower recombination loss. XPS results show that SEMI-KLEEN plasma cleaner can complete remove hdyrocarbon carbon contaminations on InGaAs samples in 2 seconds.
XPS analysis result of remote hydrogen plasma cleaning for InGaAs sample. Courtesy of Professor Kummel and Dr. Mary Edmonds in UCSD
SEMI-KLEEN remote plasma cleaner for ALD system