Application of Simplified Methods for Partial Environmental Assessment of Microelectronics Soldering Materials and Processes in Small and Medium Sized Enterprises

Artikel i vetenskaplig tidskrift, 2005

As a consequence of the environmental regulations becoming stricter for companies within the microelectronics business area, alternative materials and processes with lower environmental performance will have to come in use. These new materials and processes should be process validated, and environmentally assessed. The Swedish microelectronics manufacturers do not use environmental assessment tools to determine if one alternative is "greener" than the other, as they have neither time nor legislative pressure. Instead, they refer to ´lists´ regarding limitations in the use of forbidden chemicals, and compare the ´lists´ with material safety data sheets. IVF in Sweden had the task of co-ordinating a governmentally financed project of which one of the goals was to advise producers, of microelectronics, on how to compare different material/process alternatives when introducing Pb-free soldering manufacturing technology. The scope of this paper is the evaluation of simplified and partial environmental assessment methods for microelectronics soldering. The problem addressed was the identified scarce understanding and under-use of environmental assessment methodologies in the small and medium sized enterprises in the Swedish electronics industry. A subtask was to analyse if it would be possible to perform a useful evaluation in one working day. A literature study revealed that several methods exist for environmental assessment, but most of them were assessed to be too complicated for the purpose of the present study. Two methods were introduced in the project; a qualitative Checklist Method (CM), and the quantitative Toxic Potential Indicator (TPI) that was used as a screening approach. The methods were tested at a microelectronics manufacturer to find out the applicability and the easiness of use. The checklist was applied to two wave soldering concepts and the TPI was applied to two Sn-Pb solder pastes and two Pb-free solder pastes. The CM generates information that can be used in the identification of qualitative environmental aspects, and the TPI provides fast but coarse results. It was possible for the company to perform this limited environmental assessment in one working day, as the amount of available input information is fairly limited. The participating microelectronics manufacturers in this study have confirmed this. The companies will use fast, understandable and rapidly introducible methods. The TPI was easy to use practically, but the input data available was regarded as too rough to distinguish among similar solder pastes. Anyway, by using the methods described in this paper, it would be possible to perform the assessment in one working day. It was perceived as worthwhile for the CM, and also to some degree for the TPI, despite data gaps for flux constituents. It is recommended that the flux constituents of solder pastes are risk evaluated to provide data for indicator tools like the TPI. The CM and the TPI should also be evaluated in industry sectors other than the microelectronics sector. This is needed to generally answer whether there are useful and systematic methods of environmental risk evaluation in product development. In a broader view, it should be researched what barriers are hindering small and medium sized enterprises to invest more in design for environment.