Integration of environmental factors in process modelling for printed circuit board manufacturing. II. Fabrication

This paper presents a set of thermo-mechanical process models for unit processes in inner and outer layer circuitization. By assessing the thermal, mechanical and chemical behavior of these processes, energy utilization and raw waste mass streams can be estimated from process and board design parameters. The processes modeled through this methodology include laminate core fabrication, resist coating, exposure, development, copper etch, resist strip, oxide treatment, lamination, drilling, desmear/copper plating and solder masking. For each process, key solid, liquid and vapor waste streams are predicted through mass balance and thermal and fluid losses determined, The raw mass outputs can be weighted through a multi-criteria health hazard assessment to determine comparisons for waste stream "quality" within the control volume of the facility. In this manner, hazard assessment for products or facilities can be evaluated from the unit process level. A case study of a six-layer PCB design for a computer workstation is presented to illustrate design trade-off analyses and integration of the process models within a computer-aided design environmen.,.