Edwards introduced a hot trap + pump combo that thermally decomposes liquid diethyl zinc (DEZ), used in depositing some transparent conductive oxide (TCO) films in thin film solar manufacturing, before it can damage the pump.
May 17, 2011 – BUSINESS WIRE — Edwards, vacuum and abatement equipment and services supplier, introduced a patented hot trap designed to thermally decompose the liquid diethyl zinc (DEZ) used in depositing some transparent conductive oxide (TCO) films in thin film solar cell manufacturing.
If unreacted DEZ enters the vacuum pumps during the deposition process, it decomposes, coating pump surfaces and significantly degrading pump operating lifetimes. Maintenance cycles can be extended by eliminating this unreacted DEZ.
TCO films are traditionally indium tin oxide (ITO) and deposited via plasma vapor deposition (PVD). Newer zinc oxide films are applied with chemical vapor deposition (CVD), which uses DEZ as a precursor. Zinc oxide-based TCO films deliver a surface topology that improves the light-capturing process.
Edwards’ heat trap is designed to prevent DEZ from entering the vacuum pump, and iXH harsh process pump has a low internal operating temperature, which will minimize thermal decomposition.
Pumps can fail in less than one week due to DEZ coating, in extreme cases, said Dr. Allister Watson, product manager for Edwards FPD drypumps. The hot trap can extend pump maintenance intervals up to six months.
Gases leaving the process chamber pass through the Edwards hot trap before entering the vacuum pump. The trap’s replaceable cartridges are heated to a temperature that optimizes DEZ decomposition, while the gas path allows enough time for decomposition without restricting flow. Cartridges require monthly replacement, and can be cleaned and reused.
Edwards’ iXH harsh process dry pumps are designed to handle high powder loads, high flows of corrosive cleaning gases and large hydrogen flows associated with thin film silicon photovoltaic deposition processes. The iXH also offers a range of operating temperatures that can be tuned to specific process requirements. The pump is up to 40% more energy efficient than previous generations.
Edwards is a leading global technology and environmental business supplying integrated vacuum and exhaust management solutions to manufacturers of semiconductors, flat panel displays, LEDs and solar cells, as well as vacuum technology for industrial, scientific, process and R&D applications. For more information, please visit www.edwardsvacuum.com.