In the early 1980's, Thermal Circuits introduced HTB etched foil element heaters to the Semiconductor industry to heat acid in portable wafer processing baths. It replaced hot plates that only heated from the bottom. The five-sided etched foil heater wraps the corresponding five-sided inner bath vessel with a combination of uniform and profiled heat. The etched foil heating process is designed to quickly bathe boatloads of wafers and other parts.

The etched foil elements are compatible with Thermal Circuits High Temperature Binder Inorganic and Organic coatings and with fabrication materials such as fiberglass cloth, fiberglass mat, mica, and ceramic fiber insulating carriers. The HTB coatings protect and immobilize the elements, yet allow them to expand and contract at watt densities two to three times greater with temperatures up to 1200° F.

The HTB etched foil heating construction is also used for wet processing equipment in-line heaters. Thermal circuits recommends electrical insulation depending upon the materials used in the customer's product, glass, plastic, coated or uncoated stainless steel. The use of quartz in the etched foil heater allows for a direct mount without insulation and is preferred by designers for high-wattage and high-temperature applications.

Although application similarities exist in the etched foil heating technology employed in Chuck Technology Integrated Circuitry, there are enough variables in wattage, temperature, and mounting methods to require designers to pay special attention to combining alternative insulations and films in order to insure the success of the end product. For example, this heater/heat sink assembly consists of an etched foil element encapsulated in a combination laminate of two thin film insulators: one Kapton® polyimide, the other Teflon®. The heater mounts to an anodized heat sink and a sensor is located in the center pedestal. Multi-heater/heat sink assemblies incorporate into multi-port boards designed to rapidly load/unload for "burning in" of silicone discs used in the computer industry.