| 摘要 |
PURPOSE:To eliminate the warpage and twist of a wafer by etching only the surface of the wafer and remaining the oxidized film on the back surface as it is, thereby eliminating the necessity of cutting the back surface. CONSTITUTION:A semiconductor wafer formed with a pattern for opening a window is placed on a pin 12 with the front surface downside, and a chuck 20 is lowered. At this time nitrogen gas is initially sprayed from a tube 27 to the lower surface of the chuck 20, and when the chuck approaches the wafer S, a pressure sensor senses the pressure to switch a valve 26, thereby communicating it with a vacuum tube 28. Thus, the chuck 20 attracts the wafer to the lower surface. Then, etchant is upwardly sprayed from a tube 13 to allow the etchant to be contacted with the downward surface of the wafer S, and to flow down along the surface. In this case, the etchant does not creep to the back surface, and only the front surface of the wafer is etched. |
