Protection of Vacuum Pumps with PV Blowback Filtration UnitsThe exhaust gases out of Czochralski pullers used for monocrystalline ingot growing contain dust particles that form by condensation above the silicon melt. This dust needs to be filtered to protect people, the environment and the vacuum pumps.
Fine silicon dust is highly reactive and immediately oxidizes to SiO and SiO2, an exothermic reaction. Depending on the dopant, this dust can be very hazardous.
- Oxidation of the Si/SiO to SiO2 occurs in the filter vessel under well controlled conditions.
- Extremely robust PSS filter elements are resistant to high temperatures and provide optimum retention of the silicon dust.
- These filtration units are available semi or fully automated.
- Blowback units are typically in service for several years without a filter change-out.
- Cost of ownership model shows return of investment (RoI) in one to two years.
- No leakage, long pump life, low cost of ownership are the hallmarks of the Blowback Units.
PV Blowback Unit Set-up
Gas Purification for Czochralski Puller ToolsWhen crystalline defects in the ingot appear during the growth process, remelting is necessary to remove them. This is costly because it lengthens the growth cycle, negatively impacting tool throughput. Gaskleen purifiers remove moisture to the sub ppb level from argon gas used as a blanket wtih CZ Puller tools.
- Crystalline defects are minimized during silicon ingot growing.
- Additional remelting steps are reduced or eliminated.
- See related Application Bulletin: "Gas Purification for Czochralski Puller Tools" (PDF)