A method of processing a silicon substrate can include etching the silicon substrate with a first etchant having a first concentration and etching with a second etchant having a second concentration. In an embodiment, the second concentration of the second etchant can be greater than the first concentration of the first etchant. In one embodiment, the first etchant can be a different type of etchant than the second etchant. In an embodiment, the first and second etchant can be the same type of etchant. In some embodiments the silicon substrate can be cleaned with a first cleaning solution to remove contaminants from the silicon substrate prior to etching with the first etchant. In an embodiment, the silicon substrate can be cleaned with a second cleaning solution after etching the silicon substrate with a second etchant.