Complex sentence: Q-Cells, Canadian Solar, and Calisolar were using Timminco UMG was able to produce UMG-Si with 0.5 ppm boron for $21/kg but was sued by shareholders because they had expected $10/kg.
Split into simpler sentences: Q-Cells, Canadian Solar, and Calisolar have used Timminco UMG. They were able to produce UMG-Si with 0.5 ppm boron for $21/kg but was sued by shareholders because they had expected $10/kg.