| 摘要 |
<p>A method for forming a metal interconnection in a flash memory device is provided to form a bitline having uniform sheet resistance in every wafer or lot by uniformly forming a metal interconnection for a bitline connected to a drain contact plug in every wafer or lot. A first interlayer dielectric(111) is formed on a substrate(110) having a contact plug. An etch stop layer(112) is formed on the first interlayer dielectric. A second interlayer dielectric(113) is formed on the etch stop layer. A hard mask is formed on the second interlayer dielectric by using the same kind of material as that of the etch stop layer. The hard mask is etched to form a hard mask pattern(114a). The second interlayer dielectric is etched by a first etch process using the hard mask pattern as an etch mask to form a trench to which the etch stop layer is exposed. The hard mask pattern and the etch stop layer exposed through the trench are selectively removed by a second etch process. A spacer is formed on the inner surface of the trench by using the same kind of material as those of the first and the second interlayer dielectrics. A metal interconnection is filled in the trench, connected to the contact plug. The hard mask is can be made of a nitride layer. The second etch process can be a wet etch process using a phosphoric acid solution.</p> |
