Wet Spray Process Ultrasonic Nozzle Systems for Solar Cell Manufacturing
Sono-Tek coating systems offer significant cost savings over vapor deposition in many solar cell coating applications. There are 3 main types of applications using Sono-Tek ultrasonic spray equipment in silicon solar cell manufacturing:
1. Selective Fluxing of Solder Bus Lines on Photovoltaic Si Cells
Precise, targeted deposition and controlled velocity of the flux spray confines the flux to solder bus areas without overspray onto other areas of the cell. The ultrasonic vibration of the SelectaFlux nozzle system makes it impossible for the nozzle to clogg, with only a monthly cleaning recommended. The system is easily installed on existing Tabber Stringer lines.
2. Liquid Dopant Solgel Solutions, Phosphoric & Boric Acid Doping for N- & P-type Wafers.
Sono-Tek offers several options for scalable doping processes, from fully enclosed R&D systems such as the ExactaCoat SC to inline systems such as our WideTrack wide area coating system for continuous high volume production. Advantages over traditional POCl3 batch doping processes:
- Reduced cycle time with continuous inline process
- Uniform thin films readily adhere to silicon surface
Ultrasonic spray is a cost effective alternative to tube furnace BBr3 boron diffusion for P-type silicon or POCL doping for N-type silicon wafers. Sono-Tek ultrasonic spray systems reduce manufacturing equipment costs, providing uniform thin films of Boric acid onto P-type wafers or phosphoric acid onto N-type wafers prior to inline diffusion furnace processes. The ChemCoat Si is an inline doping system designed for 38″ (965 mm) spray coverage in automated high volume wafer processing.
3. Anti-reflection Coatings
Sono-Tek ultrasonic nozzles are used to apply thin film nanocoatings of TiO2 and SiO2, reducing surface reflection and maximizing cell efficiency. WideTrack stationary ultrasonic spray systems are designed to integrate with existing manufacturing lines.
All Sono-Tek ultrasonic nozzles feature:
- Up to 80% reduction in material consumption
- Reduced wasteful overspray and atmospheric contamination
- Minimal servicing and downtime
- Spray patterns that are easily shaped for precise coating applications
- Highly controllable spray that produces reliable, consistent results
- No moving parts to wear out
- Ultra-low flow rate capabilities, intermittent or continuous