| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of photolithographic processes by integrating an ion implantation process and an oxide film removing process. SOLUTION: After processing gate electrodes 7 of a memory cell region 1 and the gate electrode 8 of a high breakdown voltage transistor 3, only a portion between the gate electrodes 7 of selector gate transistors is opened by a resist pattern. An ion-implanted layer 4a for adjusting a threshold is formed below the gate electrodes 7, and then an oxide film 14 is separated. Thereafter, a nitride film 15 and a BPSG film 16 are buried and planarized, and then an oxide film 17 is formed. In a photolithographic process for forming contact holes 18 and 19; the oxide film 17 and the BPSG film 16 are etched, the nitride film 15 is etched, and the oxide film 14 is etched with different selectivity which can reduce the number of the photolithographic processes without giving damages. COPYRIGHT: (C)2006,JPO&NCIPI
|
