New Improved Heater Design

• Tighter temperature control enabled by microprocessor controlled thermocouple
• Improved reliability of heater control system due to no-arc relay circuit
• Improved temperature uniformity with optimized design of multiple heating zones
• Improved heater lifetimes and ease of installation with new clam-shell design of heaters
• Improved design of thermal fuse, eliminating nuisance failures caused by transient thermal spikes
• Special temperature settings available on request

Improved Process Performance - Yield, Uptime

• Isolates pump lines and traps downstream
• Reduces particle generation with slow pump downs
• Stops unwanted sublimation of process by-products, heaters keep valve clean
• Reported increase in time between maintenance cycles from 2 weeks to 12 weeks or 20 runs to 145 runs

Enhanced Heater Safety

• Outside temperature of heater 45-65°C, safe to touch
• Integral thermal fuse
• Ground Fault Equipment Leakage Circuit Interrupter power cord option eliminates shock hazard

Better Thermal Performance

• Reduced power consumption
• Improved temperature uniformity, prevents cold zones
• Patented design retains heat and improves thermal safety

Valve Features

• Formed bellows for reduced particle buildup and longer cycle life
• Heavy duty spring allows the valve to seal with contamination
• Second stage allows for soft pump down
• Adjustable orifice allows for controlled pump down
• Thumbscrew and micrometer actuators available for bypass valve
• Three stage valves available on request

Other Important Features

• May be used in vacuum forelines, or the exhaust side of the pump
• Fast delivery of standard heaters
• Controller LED confirms that the heater is operating properly and at pre-set operating temperatures
• Low temperature alert option warns when heater is cold
• Specially designed valves with heaters available

Semiconductor CVD and etch processes produce gaseous by-products that can readily be pumped out of the reaction chamber. However, they usually solidify in a vacuum pump line since the line temperature is lower than the reaction chamber. A clogged line means longer down time and lower product yield.

A common process is LPCVD silicon nitride. Since sublimation is temperature driven, use heat to maintain the by-products in the vapor phase and use cooling to intentionally sublimate the vapors in the trap.

Heaters have been used successfully in tungsten and oxide etch systems. Heating helps in TEOS CVD systems where a very tight temperature control is required. Some processes yield unintentional by-products. For example, diammonium hexaflurosilicate (NH₄)₂SiF₆ has been observed in a silicon nitride PECVD process due to the cross chemical reaction of the products formed in the deposition and etching processes. It is a sublimable material that lends itself to heating and cooling strategies. Please consult MKS application engineers for further assistance.