A Substrateless Process for Sustainable Manufacture of Electronic Assemblies

The exponential growth in worldwide production and consumption of electronics, and the short operational lifespan of many products, has resulted in increasing amounts of electronics waste. There is enormous pressure on electronic product manufacturers to reduce the consumption of materials and their subsequent impact on the environment, especially at the end-of-life, through such measures as the EU Directive on Waste Electrical and Electronic Equipment (WEEE). Ideally any product should be separable into its constituent parts at end of life for subsequent reuse, recycling or disposal. However separation of a typical electronic assembly into its constituent parts is problematic because of the intimate nature of the bonding between the glass fibre/thermoset composite laminate, the laminated and embedded copper conductor layers and the soldered electronic components. To address these problems, an alternative processing route for manufacture of electronics assemblies is proposed, in which the electronic components and metal content can be easily separated out from the organic content at end-of-life. No separate printed circuit board is used to interconnect the components so the process may be termed as "substrate less". The route has the additional advantage that standard electronic assembly equipment can be used. In this work the process route is described and the implications of adoption for the electronics manufacturing industry considered. The results of initial proof of principle trials are described, and conclusions are drawn as to the development work required to allow adoption of the process by the industry.