Magnetic print head chips comprising 3D-redistribution layers, MEMS coils and magnetic circuits in a Multi-Chip-Module for serial production

Inhalt:
Sensitec GmbH in cooperation with France based Nipson SAS has developed and optimized a fabrication process for a Multi-Chip-Module comprising a magnetic print head chip and up to 22 diode chips assembled in flip-chip technology. The approx. 30 mm x 13 mm large print head chip uses Sensitec’s wafer fab technology of electroplated micro coils with magnetic poles and buried return boxes as well as multiple BCB isolated 3D-redistribution layers. Each print head consists of up to 616 fully functional micro-coils, magnetic poles and return boxes. Each 125 mm silicon wafer used as substrate material carries 20 print head chips. Several examples of actions as part of the continuous improvement process during the production ramp-up and serial fabrication of the print head chips are described and discussed in this paper.