Robust Aluminium Nitride Package Technology for Multichip Modules Available to Purchase

The advent of novel advanced packaging technologies such as multilayer thin‐film interconnect, combined with continuous improvements in IC clock speed and circuit performance, has placed extreme demands on electronics packaging and package materials. Aluminium nitride (AIN) ceramic offers significant opportunities and advantages for package design, particularly where the effective thermal management and overall reliability of large devices are a high priority. AIN has already been successfully employed at the substrate level for the enhanced thermal relief of power devices. Examples of these applications include heat sinks and device mounts for thyristor modules, power transistors, solid state relays, power SCRs, switching modules, LEDs and various RF package configurations. Both bare and metallised AIN substrates are beginning to find application as a substitute for beryllia (BeO) in mass market and high reliability automotive electronics applications. Successfully implementing AIN in a high level electronics packaging application requires a systems approach in which the intrinsic properties of AIN are considered as ‘first principles’ in shaping the package design process. The unique physicochemical and mechanical properties of AIN require the development of specialised metallisation and co‐firing processes to fabricate the advanced components necessary for hermetic packaging of complex devices and multichip modules. This paper presents a practical and mass manufacturable AIN‐based package tailored to these high level applications. The package design is unique in that it provides for the total separation of the electrical‐signal conduction from the mechanical support/mounting functions of the package. Such a separation of the functions improves both the package durability and reliability relative to currently available electronics packages of conventional designs.