| 摘要 |
PURPOSE:To allow a plurality of kinds of highly accurate in-plant resistance regions to coexist together in an IC and the IC to perform simplification of processes as well as a reduction in the production cost, by making use of a pattern as it is, which is formed with high accuracy according to a first resist pattern, thereby carrying out a second ion implantation. CONSTITUTION:An oxide film 26 is formed at the whole surface of an epitaxial layer 23 and a first resist pattern 27 is formed by coating, baking, and developing a positive type photoresist and then, a pattern of the oxide film 26 corresponding to the first resist pattern 27 is formed by treating the oxide film 26 with an anisotropic etching process. Then, a first ion implantation with boron B is carried out to form first and second resistance regions 28 and 29 which have the same impurity concentration at the surface of two islands 25. Further, a second resist pattern 30 is formed by coating, baking, and developing a negative type photoresist film in a state that the first resist pattern 27 is removed or left and a second ion implantation with boron B is performed by using again the first resist pattern 27 or the pattern of the oxide film 26 as a mask. |
