Two-In-One Texturing and Polishing in One Solution

Texturing and polishing crystalline silicon in the PV industry are both time consuming and inefficient, the need for a streamlined solution is prevalent. To obtain high conversion efficiency surface decoupling is needed, one side of the wafer is ideally textured while the other is completely polished. The standard industrial process results in a total silicon loss of 40 mu m and a complete surface decoupling cycle time in the order of an hour from an as cut until diffusion ready. For an industrial wafer thickness of 180 mu m more than 20% of the silicon is lost. In addition to silicon loss, there are multiple wet processing steps needed for decoupling which are time consuming and hinder the high throughput manufacturing needed to achieve the ultimate goal of a low per watt peak price. The technique is proposed in this paper decouples the front and rear surfaces and utilizes in only one wet process step for both texturing and polishing. This process simplification leads to significant savings by decreasing costly cycle time, saving consumables and reducing the amount of silicon loss.