High Speed Laser Scribe System for Large Area Thin Film Solar Cell Manufacturing

Abstract

Recent advances in laser sources and laser scribing process techniques are providing significant improvements in manufacturing throughput, cell efficiencies and production yields for the industrial manufacture of thin film solar cells. Widespread adoption of these improved technologies will contribute to accelerated reductions in manufacturing cost and further enable market adoption of thin film photovoltaic solar cells. We describe a novel new distributed laser scribe system design based on an air bearing linear motion stage which is optimized for high throughput laser scribing of large area glass photovoltaic thin film panels. The design concept is shown in the Fig. 1. This system provides six beam lines, each supplied by an individual compact Explorer laser. Such system enables multiple laser scribes to be “written” through the stationary glass from below at speeds up to 2 m/s yet with very high accuracy (Fig. 2). This is a major improvement on existing designs that incorporate single laser beam split into 4 or 8 beam paths, scanners, mechanical bearings, or require fast movement of the glass substrates and thus are limited in their speed and or accuracy, usable life time, and scalability to larger panel sizes. This large area laser scribe platform is used to characterize the scribing processes in amorphous silicon process type thin film samples, performed by using multi-kHz q-switched solid state lasers laser of ns pulse duration and for panel sizes up to 1.3m×1.1m. The scribe width along the scribe lines, their parallelism and their sensitivity to the ambient temperature conditions were measured and characterized