Improved cleaning performance for silicon wafer assemblers

Electrochemicals manufacturer Electrolube has developed an innovative cleaning solution called Safewash Super (SWAS) for PCB wafer assemblers, following close collaboration with a number of manufacturers to improve their cleaning capabilities as well as speed up throughput, reduce costs and decrease environmental impact.

While cleaning processes can vary from plant to plant, the silicon wafer manufacturers in all had many issues in common. These included a bottleneck in production due to a slow cleaning process; use of a solvent-based cleaning product which produced disappointing cleaning outcomes as well as increased rejects and rework; and concerns with environmental impact with regard to storage, transport, disposal and employee safety. The existing solvent-based products in use also displayed a relatively low-contamination load-bearing capability, which resulted in a more frequent need to replace material for a fresh batch.

Electrolube recently introduced SWAS into the cleaning process of a major multinational water manufacturer. This particular customer used a US-made, solvent-based cleaning agent in a multichamber machine, consisting of five cleaning tanks plus a loading and unloading station.

As a direct result of introducing SWAS into the process, the company was able to reclaim considerable floor space at its facility by reducing its existing five-tank configuration to a three-tank configuration (clean/QDR and QDR de-ionised). SWAS significantly improved the assembler’s cleaning performance with no residue on the wafer and enabled throughput to increase by as much as 50% — a vast increase assisted by the decreased time in the cleaning tank and the reduced tank configuration.

SWAS can absorb 5–15% of its weight of flux (RA, RMA, no-clean and water-soluble) while still cleaning to military standards. Due to the product’s capacity to hold high levels of contaminant particles, the customer effectively reduced the number of cleaning agent changes per week. Costs were reduced even further thanks to the water-based formulation of SWAS, making it cheap to transport and dispose of after use. Designed to clean to well within the world’s military cleanliness standards — ANSI-J-001B/IPC TM-650 — SWAS is non-flammable, ozone-friendly and biodegradable. The cleaning agent is low-odour and is safe for employees to work with and store.

SWAS was found to be a cost-effective and technically capable cleaning product in this application, as well as for several other wafer manufacturers and PCB/production equipment cleaning applications. It can remove all types of flux residues quickly and efficiently, with minimal environmental effect using readily available cleaning equipment. It is particularly suitable for the removal of stubborn flux resides and no-clean fluxes, which can be difficult to remove.