Abstract

The article review the processes in electronics manufacture.

Simiconductor wafer manufacture where circuits are itched onto silicon wafers. Processes include crystal purification and growth, wafer preparation, epitaxy and oxidation, photolithography, doping and type conversion, metallisation, interconnections and packaging. This is followed by the assembly of the semiconductors including die separation and bonding, wire bonding, encapsulation, marking and testing. The encapsulation process may involve isocyanates, acrylates or epoxy resins, possible causes of occupational asthma.

Printed circuit board manufacture includes resin bonding, impregnation, laminating, photomasking and etching, cutting and drilling, marking and testing. The printed circuit boards are then assembled with components which need to be soldered into the printed circuits. This process may be close to automatic flow solder machines, or may involve hand soldering, particularly when rectifying faulty connections. The solder flux fumes are the major hazard, but rectification may involve using a soldering iron to burn through a surface coating, which may liberate isocyanates. The board is then ready for assembly into the final product.

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