Development of a Generic Model for Life Cycle Inventory and Environmental Assessment of Upstream Processes for Electronic Products

Licentiate thesis, 2002

The goal with the present thesis is to develop tools, methods and models to assess the upstream processes in the life cycle assessment (LCA) methodology for current and new electronic products. The goal is to get a better understanding on how to collect data to be used in a life cycle inventory (LCI) and use life cycle approaches to environmentally assess the electronics. Firstly, a comprehensive LCA from cradle-to-grave of a private branch exchange (PBX) was performed and an LCI database in the LCA software EcoLab was built up. Secondly, a model and method for LCI data collection from cradle-to-gate of the upstream processes, which could be applied to any electronic product, was developed. Thirdly, a gallium arsenide (GaAs) Monolithic Microwave Integrated Circuit (MMIC) Switch Product based on the a System-In-a-Package (SIP) concept using a Liquid Crystalline Polymer (LCP) substrate was manufactured and the developed model for LCI data collection was applied to assess the environmental load. There exist several environmental assessment approaches for electronics, but still no effective model for LCI data collection exists. The objective is to develop a model for LCI data collection of the upstream processes of electronic products, apply it and find the environmental load of a GaAs MMIC Switch Product based on so-called SIP concept utilising a LCP substrate. EcoLab and available literature data were used to analyse the environmental loads. The results show that manufacturing of hardware has a significant impact on the LCA results for a telecommunications exchange. For Paper I, as much as 50 % of the upstream manufacturing processes applied to the raw materials to transform them into components were left out. Integrated circuits and printed wiring boards dominate the hardware contribution to the environmental load of the whole telecommunications exchange. The observed significant environmental impact of inductors in the LCA in paper I may well be an effect of the LCI data used being poorly representative of the full range of inductive components. An LCI of a digital telephone would lead to more than 120 unit processes requiring to be inventoried, but some of the unit processes for silicon containing components are similar, which would simplify the inventory. The result of an environmental assessment of the manufacturing process for a GaAs switch showed that spin coating and deposition are environmental “hot spots”. From the present work it is shown that the data gathering requirement is vast, but not as large as it would be if every component had to be inventoried from cradle-to-gate. The data collection can be minimized if the proposed model for data collection is used. In the present thesis it is also shown that the data collection model could be used for a GaAs MMIC SIP switch module. The upstream processes are not negligible in LCA of electronics, especially not the processing of monocrystalline wafers.