Life cycle assessment of cleanroom for micro-electro-mechanical systems fabrication with insights on sustainability

Abstract

The cleanroom is used for manufacturing of high accuracy, high sensitivity, and small-sized Micro-electro-mechanical systems such as micro-sensors and micro-actuators. It is a controlled environment, in which the contaminant particles, temperature, and humidity are maintained within limits recommended by the International Standards Organization (ISO). The design, construction, and assessment of the design sustainability and energy sustainability during full production time and idle-time of a cleanroom are reported in this paper. Evaluation of design sustainability of the present cleanroom was carried out through experiments on the time taken for scavenging of contaminant particles out of the positive pressure cleanroom by the air handling units. The cleanroom designed in the present work scavenges all sizes of contaminant particles to as low a value as 2% of the prescribed ISO class within 10 min. Assessment of energy sustainability of the cleanroom was done using two metrics of net total pressure efficiency (NTPE) and total energy performance index (TEPI) through a novel adaption of their concepts to the cleanroom. With measured values of NTPE of about 35% and TEPI of 5.6 for the entire MEMS production subarea of the cleanroom consisting of twelve fan filter units, the results of the present work are in close agreement with these metrics reported for a single fan filter unit in the literature. Finally, a novel adaption of the existing life cycle assessment (LCA) methods to cleanroom resulted in an environmental sustainability score of 56.1/60. The details of the work done on the environmental sustainability of the cleanroom are also presented. With the rapid advancements in technology, the sustainability and feasibility demonstrated in the present work through the novel way of applying lifecycle assessment methods, and two energy sustainability metrics to determine the efficacy of the design of a MEMS cleanroom can prove beneficial for developing economies such as SAARC and African countries.