A multi-chip board for X-ray imaging in build-up technology

A prototype multi-chip hybrid pixel detector has been developed, based on tiling together eight Medipix2 readout chips onto a single Silicon sensor with a sensitive area of 28×56 mm2, for a total of about 0.5 Megapixels. in difficulty of this approach is the high density of interconnections, needed to read out all the circuits in such a tiled multi-chip array. The level of connectivity between the readout circuits is drastically reduced by the use of a high-speed serial protocol, allowing the use of Low-Voltage Differential Signalling (LVDS) at frequencies above 100 MHz. nt the multi-chip hybrid, we are using a new high-density printed-wire-board technology called “multi-layer build-up with staggered micro-vias” to accommodate the 128 wire-bonds per chip on a nine-layer printed wire board, with a smallest feature size of 60 μm line width, and a pitch of 110 μm. This accuracy is maintained over a board size of 110×55 mm2.