In thick-film hybrid integrated circuits, the substrate plays a role in carrying thick-film components, interconnections, external components and encapsulation. In high-power circuits, the substrate also plays a role in heat dissipation. The requirements of thick film circuit for substrate include: high flatness and smoothness; Good electrical performance; High thermal conductivity; Have thermal expansion coefficient matching with other materials; Good mechanical properties; High stability; Good processing performance; cheapness. Generally, 96% alumina ceramic substrate is selected for thick film circuit. Beryllium oxide substrate can be selected if better heat dissipation conditions are required.
In thick film hybrid integrated circuits, passive networks are mainly formed by printing various pastes on the substrate into graphics and sintering at high temperature. The materials used include conductor paste, dielectric paste and resistance paste.
Thick-film conductor is an important part of thick-film hybrid integrated circuit. It plays the role of interconnection of active devices, multi-layer wiring, capacitor electrode, lead soldering area of external components, resistor end materials, low-resistance resistors, thick-film microstrip, etc. Among the conductor pastes, the common thick film hybrid integrated circuits use palladium and silver materials, gold pastes are used in some military circuits and high-precision circuits, and silver pastes are used in some circuits with low requirements.
Thick film resistor paste is also an important part of thick film hybrid integrated circuit. Thick film resistor made of thick film resistor paste is one of the most widely used and important components. Thick film resistance paste is composed of functional component, bonding component, organic carrier and modifier. Generally, DuPont resistance paste is selected.
Thick-film dielectric paste is applied to realize the thick-film of thick-film external capacitor, the multi-layer of step-line conductor, and the performance parameters of thick-film resistor are not affected by external environment. It includes capacitive dielectric paste, cross and multi-layer dielectric paste and encapsulated dielectric paste.
Post time: Feb-06-2023