Particle Characterisation Supports Cost Control in Solar Cell Manufacture

Worldwide demand for photovoltaic (PV) solar cells is fuelling the emergence of a strong manufacturing sector across Europe and Asia. In support, the Sysmex FPIA-3000 Flow Particle Image Analyser from Malvern Instruments is being used to aid cost control and waste reduction by providing the particle size and shape data necessary for effective recycling of the high value slurries used in cutting silicon wafers. Silicon carbide slurry represents a significant cost in wafer manufacture with one estimate placing the operating cost of running 10 wire saws at as high as $16 million per year, making slurry recycling a highly desirable process.

Multi-wire saw cutting processes that rely on abrasive silicon carbide slurries are used to cut silicon wafers for PV solar cells. These allow the slicing of thousands of wafers in a single run. However, over time, the slurry carried by the wire becomes contaminated, creating a build-up of waste silicon and worn abrasive particles and reducing the effectiveness of the wire-saw process.

By monitoring the size and shape of particles present, the Sysmex FPIA-3000 allows optimum control in slurry recycling. In addition, by characterising the slurry itself, the particle size and particle shape distribution of the silicon carbide can be tuned to enable thinner cuts between each wafer, thereby wasting less raw material. Capable of measuring tens of thousands of particles in just a few minutes, the Sysmex FPIA-3000 uses imaging flow cytometry to measure suspended particles passing through a sheath flow cell, providing robust data that can be used to optimise manufacturing processes.