C-Hybrid Integrated Circuit Printed
Hybrid integrated circuit
Thin film technology was also employed in the 1960s. Ultra Electronics manufactured circuits using a Silica Glass substrate. A film of Tantalum was deposited by sputtering followed by a layer of gold by evaporation. The Gold layer was first etched following application of a photo resist to form solder compatible connection pads. Resistive networks were formed, also by a photo resist and etching process. These were trimmed to a high precision by selective adonization of the film. Capacitors and Semiconductors were in the form of LID (Leadless Inverted Devices) soldered to the surface by selectively heating the substrate from the underside. Completed circuits were potted in a diallyl phthalate resin. Several customized passive networks were made using these techniques as were some amplifiers and other specialized circuits. It is believed that some passive networks were used in the Engine Control Units manufactured by Ultra Electronics for Concorde.
Some modern hybrid circuit technologies, such as LTCC-substrate hybrids, allow for embedding of components within the layers of a multi-layer substrate in addition to components placed on the surface of the substrate. This technology produces a circuit that is, to some degree, three-dimensional.