Sysmex Flow Particle Image Analyzer FPIA-3000

Summary

The Sysmex Flow Particle Image Analyzer FPIA-3000 from Malvern Instruments measures particle size and shape in wet suspensions. It is proving ideal for monitoring the deterioration of abrasive slurries used in the wire saw cutting processes in solar cell production and also for monitoring the slurry recycling process. The fast, efficient quantitative particle analysis it provides enables manufacturers to optimise slurry use and to recycle slurry without compromising final product quality. This contributes to minimising raw material use and the reduction of industrial waste.

Description

In solar cell production for the photovoltaic, semiconductor and microelectronics industries, the main technique for slicing silicon blocks into wafers is multi wire sawing, involving the use of abrasive slurries. Traditionally after the cutting process, the exhausted slurries are discarded. Slurries become exhausted when they contain a high proportion of fine silicon powder and broken abrasive particles. In order to improve efficiency, reduce production costs and reduce waste, the industry is moving away from discarding the abrasive slurry and towards recycling. To do this it is necessary to carefully monitor the in-use slurry for the presence of unwanted particles that build up during the sawing process and which would reduce the quality of the final product. Slurries are then sent for recycling where reusable abrasive material is separated from fine material by centrifugation and reintroduced into the liquid.

The Sysmex Flow Particle Image Analyzer FPIA-3000 allows particle analysis of slurry samples in real-time. This enables its use in monitoring their deterioration in order to establish when a slurry should be withdrawn from production and recycled. The suspended sample is measured in real time and images of up to 360,000 particles are captured by a CCD camera. The system is extremely easy to use with analysis driven by Standard Operating Procedures requiring just single-click operation. Analysis takes only around 2 minutes and delivers statistical results in terms of particle size, shape, distributions and particle count. This allows quantitative monitoring of the percentage of unwanted fine components in the slurry. Additionally, two-dimensional scattergram plots of particle size versus shape means that primary particles can be distinguished from aggregates.

Innovative aspect

The Sysmex FPIA-3000 enables the application of real time particle size and shape analysis to the abrasive slurries used in wire saw cutting processes. This means they can be monitored routinely for the presence of unwanted particles to indicate slurry deterioration. Decisions on when to withdraw a slurry from production for recycling can then be made quickly and with the benefit of clear data. This helps maintain optimal wire saw cutting performance and supports the optimisation of production processes. The Sysmex FPIA-3000 is also used to monitor the recycling process itself to ensure the successful removal of unwanted particles.

Benefits

The abrasive slurries used in wire saw cutting pose an environmental challenge in terms of both raw materials used in their production and issues associated with their disposal, and are a significant cost in the wafer production process. Recycling offers the opportunity to recover valuable silicon, reuse materials and reduce industrial waste. The FPIA-3000 aids the optimisation of slurry use and helps ensure efficient recycling.