Electronic systems in dense three-dimensional packages

Conventional packaging technology can frequently limit the performance and physical characteristics of an electronic system. To circumvent these restrictions, planar multichip modules (MCMs) have been developed. These MCMs place components onto advanced interconnection substrates to improve electrical and physical performance. However, poor yields and high rework cost have prevented the widespread use of this technology. The packaging technique presented by the authors utilises three-dimensional MCM technology (MCM-V) and avoids these problems. The technology can produce a system with greatly improved physical characteristics over conventional MCMs. The technique allows components to be tested at an early stage of manufacture where the added value is low, removing the need for a `known good die´ (required for planar MCMs and currently a major issue). The primary use of 3D MCMs, to date, has been to produce dense modules. The authors´ work presented here extends this technology to support heterogeneous microsystems containing a variety of devices differing in size, I/O requirements, electrical performance, thermal requirements and type (i.e. IC. discrete). In applications where chip density, speed, board space and/or performance are critical, the method presented can be advantageous