In this process the one-sided edge isolation is combined with the removal of the phosphor-silicate glass layer. The emitter layer created on the under side of the wafer during the diffusion process is isolated on one side in order to prevent malfunctions of the solar cell. In the following process which is integrated in the machine the phosphorous glass is removed from the surface of the wafer.

Inline system for wet-chemical edge isolation with simultaneous removal of the phosphorous glass layer

• The potential on the front and rear sides of the wafer is isolated by etching an isolating edge on one side of the wafer in a wet-chemical process.
• Up to 80 % lower chemical consumption compared to conventional methods
• The wafer is turned in a turning station (new development) for even distribution of the etching process on the rear side
• Stable and reproducible process values are achieved by automatic, controlled subsequent dosing
• Low rate of chemical drag-in
• Minimised rate of breakages due to gentle roller transport with small contact area
• Continual recirculation of the chemicals
• Deposit-free drying with Dry Jet Dryer
• Extendable process line