High Density Interconnect multi-chip module for the front-end electronics of the PHENIX/MVD

A multi-chip module (MCM) based on High Density Interconnect (HDI) technolo gy was developed for the front-end electronics of a high energy nuclear phy sics experiment to process charge pulses from silicon detectors. Stringent requirements in performance as well as low radiation length and minimum phy sical size of the module dictated the use of the most sophisticated MCM tec hnology available. The module handles 256 input channels on an alumina subs trate with milled cavities for die placements and four layers of thin-film traces of 42u width. A total of 20 custom integrated circuit chips and 98 p assive components are assembled on a substrate of size 43mm x 48mm. Various aspects of development efforts for the design and fabrication as well as t he electrical test results of the module are discussed.