| abstract |
A method includes forming a tri-layer. The tri-layer includes a bottom layer; a middle layer over the bottom layer; and a top layer over the middle layer. The top layer includes a photo resist. The method further includes removing the top layer; and removing the middle layer using a chemical solution. The chemical solution is free from potassium hydroxide (KOH), and includes at least one of a quaternary ammonium hydroxide and a quaternary ammonium fluoride. |