We have a new tool requiring WF6 (Tungsten Hexafluoride). Can I use a 3 stick valve manifold box in the line to feed the 3 chambers?

Delivering Tungsten Hexafluoride to a process tool can be tricky.  We’ve seen a few gas delivery system installations that have taken some effort and attention to detail to set up correctly.  Here are my suggestions:

  • Keep the gas cabinet within 50 feet of the tool
  • Chill the gas cylinder to 17ºC to stabilize the vapor pressure, and then heat the lines to the tool
  • Set the delivery pressure at -1.5 psia at static in the gas cabinet
  • The cylinder pressure should be 3 to 4 psia
  • To avoid sucking liquid into the lines, don’t go above -1.5 psia at static
  • Use 3/8″ tubing and components after the gas cabinet to point of connection with the process tool
  • Don’t put regulators in the valve manifold box (VMB)
  • Shouldn’t need to heat trace inside the VMB, BUT do so from the gas cabinet to the VMB, and the VMB to the tool.    72 – 75º from Cabinet to VMB;  80 – 85º from VMB to the tool
  • With a new gas bottle, there isn’t sufficient head to run 3 chambers, and you need to be careful not to suck liquid into the gas lines.  Chilling helps here.
  • Initially run all 3 chambers when you get a new bottle installed to verify gas flows on initial start up.  This will also verify the -1.5 psia at static setting on the standby regulator

Would be happy to talk through this a little further.  Call me (Tom Britton) at 208.890.1417

No Comments

Sorry, the comment form is closed at this time.