| 摘要 |
<p>PROBLEM TO BE SOLVED: To increase productivity of polycrystalline silicon by reducing spark discharges generated between a silicon core wire and other conductive members.SOLUTION: A silicon core wire is cut out from a columnar shape ingot of single crystal silicon or polycrystalline silicon (S101); for the purpose of removing a residual strain (processing strain on the surface) caused in a cutting process, the silicon core wire undergoes etching treatment with a mixed acid solution of hydrofluoric acid and nitric acid so that the amount removed is normally about 50μm to 200μm (S102); and then, the silicon core wire is used for precipitation reaction of polycrystalline silicon (S103). During the etching treatment step, a thick oxide film is formed on the silicon core wire surface, which causes spark discharges. In view of such inconvenience, the present invention further comprises, after the etching treatment step of S102, another step of removing the surface oxide film by washing the surface of the silicon core wire with a hydrofluoric acid solution (S104).</p> |
