| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for forming a contact plug whose depth is different by preventing the resistance increase of a contact plug, and minimizing the etching quantity of a semiconductor substrate. SOLUTION: This method for forming the metal wiring and contact plug of a flash memory device is provided to carry out a first etching process using the non-uniformity of an anti-reflection film 34, a second etching process using an etching stop film 26 as an etching stop film, and a third etching process using WSi18 as an etching stop film, to a region in which the anti-reflection film 34 having different etch targets t1 and t2 and an irregular thickness, and a contact plug exposing a gate are formed, and a region in which a contact plug is formed through which a semiconductor substrate is exposed. COPYRIGHT: (C)2007,JPO&INPIT
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