Comparative characteristics of thick-film and thin-film microcircuits

In microelectronics, two main types of integrated circuits are used: film and semiconductor ICs.

Film ICs are created on a dielectric substrate by layer-by-layer deposition of films of various materials with the simultaneous formation of trace elements and their compounds from them.

Semiconductor ICs are created by local exposure to the microregions of a semiconductor single crystal and giving them properties that correspond to the functions of trace elements and their compounds.

Combinations of these technologies made it possible to create hybrid and combined ICs that compensate for some of the disadvantages that film and semiconductor ICs have.

Film microcircuit - a microcircuit, all elements and interconnects of which are made only in the form of films of conductive and dielectric materials.

Film chip options are thin-film and thick-film microcircuits.

A thick-film microcircuit with a film thickness of 10–70 μm, produced by screen printing (screen printing).

In general, the thick-film technology consists of a series of successive identical cycles, the structural diagram of which is shown in Figure 1.

Figure 1 Block diagram of thick-film technology

Figure 1 Block diagram of thick-film technology

The basis of thick-film technology is the use of cheap and high-performance processes that require small one-time costs for the preparation of production, which makes it economically feasible in small-scale production. The high reliability of thick-film elements is due to the strong (over 50 kgf / cm2) adhesion to the ceramic substrate, which is achieved by the process of burning the paste into the surface layer of the ceramic.

Thin-film microcircuits conventionally include microcircuits with a film thickness of less than 1 μm.

In the manufacture of thin-film microcircuits, multiple processes of deposition (deposition) of various substances through stencils (masks) in vacuum are used.

The TP scheme contains the following steps:

drawing up the topology of MS and masks;
production of photo masks and masks;
preparation of substrates for drawing a pattern;
creating drawings of circuit elements;
joining active elements and conclusions to the MS;
adjustment of passive elements;
MS sealing;
parameter control and testing.
The technology of thin-film MS uses more complex methods of deposition of materials:

1) thermal vacuum evaporation;

2) cathodic sputtering;

3) ion-plasma spraying;

4) high-frequency spraying;

5) magnetron sputtering;

6) reactive spraying;

7) methods of elion technology.

The difference between thin-film and thick-film microcircuits is quantitative - in the thickness of the films and, therefore (another technological process), qualitative - other properties of the elements.

A significant drawback of thick-film microcircuits is the instability of the nominal values ​​of passive trace elements and the relatively low density of installation. Thin films provide mounting densities of up to 200 elements / cm3 and high precision elements.

Thick-film microcircuits are widely used in analog and digital devices that require high gain of transistors and resistors with large nominal values, powerful digital control circuits.

Thin-film technologies are widely used in micro- and nanoelectronics for the manufacture of magneto-, cryo-, optoelectronics products and for obtaining a wide range of optical coatings for various purposes.

See also

• The use of photolithography in the manufacture of electronic equipment