Watlow's thick film heaters on ceramic provide superior thermal characteristics, small heater profile, chemical compatibility and ultra-pure materials which are critical to successful wafer processing, testing, and packaging. Aluminum Nitride (AlN) and Alumina (Al 2 0 3 ) are preferred heater materials for many semiconductor applications.

Watlow has developed specialized processes using hybrid thick film materials to manufacture precision heater circuits on Aluminum Nitride and Alumina substrates. Thick film heaters on ceramics can now be designed with multiple circuits and ramp rates of up to 40°C (104°F) per second depending on the substrate material and application details. Thick film on ceramic is capable of high operating reliability at temperatures of 300°C (572°F) for Aluminum Nitride and 500°C (932°F) for Alumina. Contact the factory for details of ongoing extensions to both of these capabilities.

Temperature uniformity, rapid response and thickness down to 1.27 mm (0.050 in.) for 300 mm pedestal heaters make Aluminum Nitride the preferred heater material for many semiconductor applications. Watlow thick film technology gives designers the capability of multi-zoning the heater for optimum temperature performance.

Alumina, a widely used semiconductor material due to availability, relatively low cost and stable physical properties is a well established material for use in demanding semiconductor applications. It is relatively easy to fabricate into a range of shapes while remaining strong at high temperatures. It is available in purity levels of 96 percent.

Applications: • Wafer pre-heat bake stations • Photolithography track systems • Annealing • Wafer probers • Chip bonding • IC test • Atmospheric rapid thermal processing

Features and Benefits:

Multiple circuit design capability and heater patterning • Optimize heater performance for a specific application and precise temperature profile • Multi-zone capability

High thermal conductivity materials • Rapid thermal response in applications requiring fast heat up and cool down • Promotes uniform surface temperature

Thin ceramic substrate • Allows heater to be designed with a lower profile • Reduces heater mass for faster thermal cycling

High dielectric material and thick film system • Ideal for applications requiring high isolation resistance

Material compatibility • Ideal for most ultra-pure semiconductor applications • Ideal for use in demanding applications

Specifications: • Maximum operating temperatures of 300°C (572°F) for Aluminum Nitride and 500°C (932°F) for Alumina • Voltages of up to 480V~(ac) • Watt densities up to 23.25 W/cm2 (150 W/in 2) for Aluminum Nitride and 3.56 W/cm2 (23 W/in2) for Alumina • Ramping capabilities of up to 40°C (104°F) per second • Flat shapes of up to 355.6 mm (14.0 in.) square • Cylindrical shapes of up to 50.8 mm (2.0 in.) in diameter • Thickness from 0.5 mm (0.025 in.) up to 12.5 mm (0.500 in.)