The “Etching Solution and Method of Surface Roughening of Silicon Substrate”, a diamond wire technology originally invented by Green Energy Technology (GET) is officially granted patent by Taiwan Patent and Intellectual Property Office. This technology can optimize diamond wire manufacturing as well as wafer conversion efficiency. The same technology is under patent examination in China.

Currently, the usage of copper wire with slurry has been widely adopted in solar wafer slicing production. In comparison, diamond wire has higher durability and throughput than copper wire and is expected to become mainstream. Besides developing proprietary technologies in both copper wire and polishing, GET also researches on next generation diamond wire technology.

GET stated that joining wet etching and diamond wire technologies together may raise conversion efficiency of wafer by 0.4% at the highest. If GET’s high-efficient wafer was adopted with PERC technology, the conversion efficiency of multi-crystalline cell will reach as high as 19.5%, and 18.4% on average. Combining with the 140um diamond wire slicing technology GET developed, silicon material loss may be reduced for another 10%.

The surface of diamond wire sliced wafer would be too smooth with high light reflectivity, which will lead to low absorption of photons, and hence reduce its power generation. Plus, diamond wire saw could cause micro damages on wafer. GET thus develops proprietary formulated etching solution along with accurate timing and temperature control for the wet etching production, to roughen wafer surface evenly and remove minimal damages simultaneously. Etched wafers will be further cleansed and dried while solution will be recycled.