Life cycle assessment of integrated circuit packaging technologies


Background, aim and scope
Nanostructured polymer particles are produced to be used in ball grid array (BGA) and chip scale packaging (CSP). The technology could replace conventional BGA and CSP metal balls, and the hypothesis is that the shift could be eco-efficient as polymer core particles increase the reliability. For the first time, these particles are environmentally evaluated.

Materials and methods
The change in GWP100 and Eco-Indicator’99 (H) scores when replacing traditional component packaging, here quad flat pack to BGA/CSP, was explored both on component and printed circuit board assembly (PCBA) level. This was followed by comparisons between BGA packages using different types of metal-plated monodispersed polymer particle (MPP) balls and conventional balls, respectively.

Results and discussion
For BGAs, the silicon (Si) die dominates CO2e emissions, but for Eco-Indicator’99(H), solder balls are not negligible. Excluding the Si die and component assembly, the LFBGA-84 to WCSP-64 would reduce CO2e by about 98% and Eco-Indicator’99 (H) by about 90%. Overall, for BGA–256 using same size balls, gold-plated MPP technology decreases the Eco-Indicator’99(H) score by about 25% compared to Pb-based or Pb-free balls. Gold production dominated GWP100 and Eco-Indicator’99 (H) for the gold-plated MPP. Each microsystem is unique, and new environmental impact estimations must be done for the sub-structures of each electronic device. Screening process-sum life cycle assessment (LCA) gives similar understanding of impacts as resource productivity methods. Even though the metal mass per ball is greatly reduced, it is a weak indicator of environmental impacts which are driven by each material’s specific environmental characteristics.

The ball share of the BGA-256 GWP100 and Eco-Indicator’99 (H) score is small, and the BGA/CSP producers can marginally improve the environmental performance by focusing on the balls. On a comparable IC packaging basis, the introduction of WCSP packaging technology implies a significant environmental footprint reduction. On PCBA level, the contribution of BGA balls is negligible. Results for metal-plated MPP BGA balls suggest that gold usage is the key environmental performance indicator of interest.

Recommendations and perspectives
Even though WCSP clearly reduces the component level impacts, the PCBA (board) level impact could increase as the CSP miniaturisation is paralleled with more PWB layers. This effect should be included in further system expansions. For LCA, in general, update of all LCIA methods, which include ozone depletion, with the latest results for dinitrogen monoxide is needed.