ECRI Microelectronics

Thick Film

Thick Film Thick film hybrid technology is a widely-used technology for the manufacture of a ceramic or other type of circuit boards. Due to its high degree of integration, thick film substrates form the basis of High Density Packages (HDP).

In an initial manufacturing phase, the structures are applied by means of a silk-screen process onto the relevant substrate material such as aluminium oxide (Al203) or alumina (AIN). Conductors, resistors, insulations and overglazes can be manufactured. Gold, silver and platinum or palladium alloys are generally used as conductive materials. The standard thick film process are printing, drying and firing. The firing process at about 850 °C guarantees the final film properties such as electrical values and adhesive strength.

Thick film technology enables a very simple and flexible manufacture of multilayers with several conductive layers on the front and back side of the substrate.

Minimum structure resolutions of 80 - 100 µm can be achieved with this technology.

Printed resistors can be trimmed to a output signal of a hybrid circuit. In principle all electronic components can be assembled on a thick film substrate. Therefore solderable as well as bondable surfaces are available.

Benefits

The benefits compare to traditional printed circuit boards are in the thermal and electrical properties of the thick film substrate material. Ceramics are very heat-conductive and as one of the chip base materials, are therefore optimally matched to the TCE of silicon. The above mentioned structure resolutions and the integration of printed, passive components make a circuit miniaturisation possible.

Applications of thick film

Due to the positive properties of the ceramic base material, thick film circuits are used as a priority in areas which are characterised by harsh environmental conditions (high/low temperatures, temperature changes, moisture, vibrations, accelerations etc.). This technology meets the requirements of the highest integration, reliability, lifetime and environmental compatibility.

Areas of application include industrial electronics, medical electronics as well as automotive and aerospace industry.