Glass Pastes

Glass Pastes

The glass pastes include the encapsulation paste FK4027 and the FKM4000 marking paste system. The glass pastes were developed for AlN substrates.

The encapsulation paste FK4027 is applied as a protective film onto thick-film resistors of the fK9600 and FK9900M resistor paste series, and onto its contacts. This prevents resistance drifts which could result from environmental factors, such as high air humidity or slight mechanical abrasion. Where high film thicknesses are required, the paste should be processed in multiple separate screen printing and firing steps.
The FKM4000 marking paste system is used to apply marking, labels and logos onto AlN substrates. However, the FKM4000 pastes should not be printed over electric functional films, such as conductors or resistors, as this could change their properties.

Technical specifications

Characteristics Unit Encapsulation paste Marking pastes
FK4027 FKM4128 FKM4889 FKM4891 FKM4893 FKM4939
Color -- Green Blue Green White Black Dark red
Viscosity Pa·S 20…50 TBD
Film surface -- Smooth, glazed Smooth, dull
Resistance change % <5 --
Fired film thickness µm 12±2 12±2
Coverage cm²/g 120±5 120±5
--from Fraunhofer IKTS

All other specifications correspond to the general process conditions.