Life cycle inventory analysis and identification of environmentally significant aspects in semiconductor manufacturing

Abstract

Intrinsically, semiconductor fabrication processes contain expensive and environmentally sensitive processes. The high purity requirements of input materials coupled with the extreme cleanliness of the processing environment provide a great challenge in managing the potential environmental impacts of this industry. High energy and water consumption and the throughput of hazardous auxiliaries give rise to additional environmental concerns. This paper presents a methodology for a Life Cycle Inventory Analysis (LCI) employed for a Motorola wafer fab. The LCI focuses on the generation of a complete data set of mass and energy flows for a wafer fab and the identification of environmentally significant aspects in wafer processing. Process modules within the infrastructure and the fab processes are identified as environmentally significant according to the consumption of energy, raw water, chemicals, gases and the origin of waste, wastewater, and emissions. The use of infrastructure facilities by fab processes is taken into account. The practical methodology worked out by Fraunhofer IZM and Motorola is a guideline to combine ecological and economical aspects and can be applied to realize environmental improvements within a company. The LCI data set is a basis for an impact assessment to gain LCA data for one of the most important processes in semiconductor fabrication. Corresponding methodologies for impact assessments will be discussed.

Life Cycle Inventory of a CMOS Chip

“…In order to effectively support semiconductor manufacturing and design decision-making, LCA must keep pace with continuous change of production technologies. Over the past several years, various forms of LCA/LCI studies have in semiconductor manufacturing have been conducted including the development of inventory models at the level of process steps and chip stack [1], inventory models at the facility scale [2,5] and overall life cycle energy and fossil fuel use [3,4]. Each of these analyses provides insight into the resource impacts of a particular functional unit or device type.…”

Life-Cycle Assessment of Semiconductors

“…In 2001, a conference paper describing a life-cycle inventory (LCI) model for a semiconductor wafer was written by an academic with support of industry members at Motorola [83]. The purpose of the study was to investigate the most important environmental impacts of a fab, rather than to perform a life-cycle analysis of a product or process.…”

“…The purpose of this chapter is to provide a detailed, complete, transparent and accurate inventory of the environmental impacts of many generations of logic chips in order to investigate trends in emissions over time and to allow LCA practitioners to more accurately model electronic equipment, as well as services enabled by electronics. Previous published work in the area of semiconductor LCA has included four environmental impact studies from industry [100,83,99,111] which report impacts for wafer fabrication and, in some cases, also use and the production of materials. Most do not include impacts associated with the production of facility infrastructure or process chemicals (aka, 'upstream' impacts).…”

Quantifying the Environmental Footprint of Semiconductor Equipment Using the Environmental Value Systems Analysis (EnV-S)

“…Although a few LCA and large system-scale studies have been conducted [1], [13]- [16], a generic LCA tool to support semiconductor manufacturing does not yet exist. Challenges still remain in developing LCA tools to keep pace with technology changes, handle uncertainty and inform detailed equipment decision making.…”