Advanced Interconnection Technology has developed a number of techniques for imaging and plating in three dimensions.  Most of these applications have a common theme to the production process but the specific technique needs to be evaluated for each product.

One area where such techniques can be very beneficial is in optoelectronic systems where for convenience the optical fibre is arranged to be aligned parallel to the sensor circuit board surface.  It is therefore convenient to mount the sensor at right angles to the circuit board surface.  As the pitch of the leads is the order of 0.3 mm and the number of connections between 40 and 100 an integrated mounting substrate is a very convenient technique.  The circuit left shows such a mounting substrate.  The substrate is 1.5mm x 2.5mm x 16mm.  The circuitry is 10 micron thick copper finished in nickel and gold.

The circuit on the right shows three dimensional interconnect applied to a stack of circuit boards encased in an epoxy resin.  The circuit boards carry ULSI Flash memory devices.  The connection points to the memory boards on the surface of the stack have been interconnected using 10 micron thick copper plating and finished with nickel and gold suitable for wire bonding.  The connection to the package header is made using aluminium wire.  Whilst not a ceramic circuit, the technology employs AIT's standard processing.

A common feature of all three dimensional projects is that each project is different.  It is invariably important to enter into discussions about three dimensional projects at an early stage.   Simple modifications introduced early can make a major difference to the timescale required to get the product into full production.