Formed Tubular Heater Keeps Semiconductor Manufacturer In The Groove

Problem:

Tubular heaters are employed in CVD (chemical vapor deposition) and PVD (physical vapor deposition) equipment used in the manufacturing of semiconductors. The tubular element is installed into a milled groove on a plate heated to 752°F (400°C) inside a wafer processing machine that etches the silicone wafer under a vacuum. The customer needed as much wattage as possible in a small area. Tight temperature control and uniformity is required. The challenge was to fit five different elements into the 0.275-inch (9 mm) diameter milled groove. Further complicating this application was the requirement that no heat transfer cement be used as it would contribute to particulate contamination in the process.

Solution:

A set of five 0.260-inch (6.6 mm) diameter Incoloy^® sheathed tubular elements at 30 W/in² (4.6 W/cm²). Special tooling was only required for the smaller, inside element bends. The heaters were skillfully formed and adjusted to precisely fit the milled groove and supplied with MGT leads 840°F (450°C). All application requirements were met with the Watlow tubular heaters operating up to design specification.

Incoloy^® is a registered trademark of Special Metals Corporation.