Thick-film technology

Thick film technology is also one of the alternatives to be used in hybrid integrated circuits and competes and complements typically in electronics miniaturization (parts or elements/area or volume) with SMT based on PCB (printed circuit board)/PWB (printed wiring board) and thin film technology.

[4] A typical thick-film process would consist of the following stages: Typically thick film circuit substrates are Al2O3/alumina, beryllium oxide (BeO), aluminum nitride (AlN), stainless steel, sometimes even some polymers and in rare cases even silicon (Si) coated with silicon dioxide (SiO2).,[5][6] Commonly used substrates for thick-film processes are 94 or 96% alumina.

Profiling is, for example, used a lot in sensor fabrication, where a circuit needs to fit round tubes or other different complex shapes.

Alternatively, ready-made inks may be obtained from several companies offering products for the thick-film technologist.

Screen-printing is the process of transferring an ink through a patterned woven mesh screen or stencil using a squeegee.

For inks based on polymers and some solder pastes that cure at these temperatures, this may be the final step that is required.

For many of the metal, ceramic and glass inks used in thick film processes a high temperature (usually greater than 300 °C) firing is required to fix the layers in position permanently on the substrate.

The abrasive technique can achieve very high tolerances with no heat and no cracking of the glass frit used in the ink formulation.

Large substrates are printed with resistors fired, divided into small chips and these are then terminated, so they can be soldered on the PCB board.

At this stage, the devices may require integrating with other electronic components, usually in the form of a printed circuit board.