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Modular Gas Line Heaters

Watlow’s gas line heaters are designed to regulate temperatures in gas lines in order to prevent condensation in the gas line.

Tetraethyl orthosilicate (TEOS), boron trichloride (BCl3), aluminum chloride (AlCl3), chlorine trifluoride (ClF3) and dichlorosilane (DCS) are gases that condense or liquefy due to a phase shift at low temperatures. In semiconductor processes, the condensation occurs in the gas line and puddles in the shower head before being injected into the vacuum chamber. A substantial number of wafer defects will occur if liquefied gases are injected into the vacuum chamber. Uniform heating of the lines with gas line heaters will prevent condensation. TEOS lines are typically heated above 194°F (90°C) and BCl3 above 86°F (30°C), depending on pressure and flow rate. The optimum line temperature will vary depending on the process parameters.


Material Maximum Operating Temperatures Maximum Watt Densities
°F °C W/in2 W/cm2
Silicone rubber  392 200 2.5 0.39
  • Watt density of 2.5 W/in² (0.4 W/cm²) on gas line O.D.
  • UL® recognized for U.S. and Canadian safety standards
  • Heaters and insulators meet UL®94-HB flammability requirements
  • Insulated straight fillers for 100% line coverage; elbows and tees are trim-to-fit to proper length
  • I.D. available: 1⁄4, 3⁄8, 1⁄2, 3⁄4 in. (6, 9.5, 13, 19 mm)
  • 120V standard, other voltages available
  • Small metal snaps
  • Heaters are insulated with a 3⁄8 in. (9.5 mm) wall, silicone rubber, closed cell sponge


  • Gas delivery lines

Features & Benefits:

Features Benefits
Easy to install two part system
  • Conveniently fits on most gas line configurations
Flexible heater design
  • Gives engineers the flexibility to easily customize the thermal profile for each gas line application
  • Allows quick prototyping to determine energy distribution requirements for process improvements
Flexible standard system components
  • Eliminates unnecessary lead times for custom designs