| 摘要 |
PURPOSE:To enable to use the wafer having sufficient thickness with which no cracks and warpage are hard to be generated by a method wherein a concaved section is provided on the back of an element when a plurality of elements are formed on a wafer and the actual thickness of the element is reduced. CONSTITUTION:An example wherein a plurality of diodes are formed on a wafer is given as follows. After a photoresist film 16 is selectively covered on the back of an N<-> wafer 15, the concaved section 14 is formed by performing an etching. Then, the photoresist film 16 is removed, an oxide film is formed on the surface of the wafer 15 and using this oxide film as a mask, the N type impurities are diffused on the concaved section and the back thereof. In addition, a P<-> layer and a P<+> layer are successively formed on the wafer 15 by partially removing the oxide film 9 on the surface and then electrodes 12 and 13 are formed on the surface and on the back. As the actual thickness of the element is determined by the t to t0, the thickness t of the wafer can be increased by having the proper depth of the concaved section 14 and the wafer having the least cracks and warpage can be obtained. |
