Tuesday, May 17, 2022

ALD Vacuum Chamber Pedestal Heater with Extended Sleeve

ALD Vacuum Chamber Pedestal Heater with Extended Sleeve

BACKGROUND
Heating solution for an ALD Vacuum Chamber Heater testing 6” (152mm) wafers up to 450⁰C.  There were obvious space constraints at the customer site requiring an extended sleeve of 25”.  The extra-long length enabled the placement of the wafer on the top surface eliminating the need to modify the existing chamber.  

SCOPE
The Vacuum Pedestal Heater needed to satisfy the following:
  • Temperature 450⁰C  
  • 25” Long sleeve with 2.75 CF Flange on the bottom 
  • Body must pass Helium Leak rate of 1 x 10̄¯9 cc/sec He 
  • 6” overall diameter for 6” (152mm) wafers
  • Top surface must have a flatness of  ± .005” 
  • Thermocouple for additional temperature measurement
  • 1,000  Watt (± 10%) , 120 Volt
  • Material was 304 Stainless Steel
OUTCOME
The Vacuum Pedestal Heater was ramped in atmosphere to 450⁰C in approximately 45 minutes.  Due to the 360⁰ weld, there was some deflection on the top surface causing it to be out of tolerance.  After the 450⁰C ramp, the Vacuum Pedestal Heater was polished down to below ± .005”.  A leak test was performed to spec and cleaned to high purity standards then shipped in clean room bags.