| 摘要 |
PURPOSE:To simultaneously perform impurity ion implantation for the ROM coding of a vertically accumulated ROM and impurity ion implantation for SD area formation and shorten a TAT. CONSTITUTION:First photoresist 4 for polysilicon patterning is hardened by the plasma etching of polysilicon 3. O2 ashing is performed for the hardened first photoresist 4 using a second photoresist 5 for ROM recording as a mask, and only the first photoresist 4 is selectively removed. Then, only the second photoresist 5 is removed and a diffused layer 8 is formed by impurity ion implantation using the first photoresist 4 as a mask. Thus, SD area formation and ROM recording are performed by implanting an ion once. |
