Product Briefing Outline: BTU International has introduced the Meridian In-Line Diffusion system. The Meridian system combines a second generation phosphorus coater with a quartz-lined diffusion furnace. The direct-spray coater now includes back-side and topside coating as well as drying capability.
Problem: The solar industry is tasked with simultaneously increasing cell efficiency while ramping production and reducing costs. The in-line process offers reduced wafer handling and greater through-put than traditional batch processing. Reduced handling translates into lower breakage rates and improved yield.
Solution: BTU’s Meridian Diffusion System increases cell efficiency through the use of backside doping and precision temperature controls while also providing high throughput and significantly reduced breakage rates through the use of in-line processing. The Meridian spray coater utilizes 3 methods of control to adjust the dopant application thickness and uniformity. Uniform, repeatable and controlled application of the dopant is required to insure consistent results. The Meridian diffusion furnace series includes temperature trim controls to maintain and adjust for temperature gradients across the width of the belt. Temperature uniformity across the belt is within +/- 2°C. This tight temperature uniformity is required to achieve uniform sheet resistance values. Tight atmosphere control is required to create a clean continuous flow of atmosphere. This is accomplished by injecting fresh process gas at specific inlets and exhausting it towards the entrance. This combined with our quartz-lined process chamber assures a clean processing atmosphere and safe removal of process effluent.
Applications: The Meridian In-Line Diffusion System is specifically designed for phosphorus diffusion of silicon solar cells.
Platform: The Meridian system is available in 4 different configurations for throughputs from 750 to 1500 wafers per hour (156mm). Standard features include: topside and bottom-side coating, precision coating control, nozzle-less spray technology, wafer drying, heater trim control, quartz-lined process chamber, controlled atmosphere and ultrasonic belt cleaner.
Availability: Q4 2008 onwards.