| 摘要 |
A method for forming a metal line of an Al/Cu structure is disclosed. In a state where a first Ti/TiN layer, an Al layer, and a second Ti/TiN layer are layered, the grooves are formed by etching the upper half the Al layer using a photoresist film, which is formed on the second Ti/TiN layer by a negative patterning process, as a mask. After a third Ti/TiN layer and a Cu layer are formed in the grooves, the third Ti/TiN (buffer) layer, the second Ti/TiN layer, the Al layer, and the first Ti/TiN layer are etched using the Cu layer as a mask. Thus, the metal line having a layered structure of the first Ti/TiN layer, the Al layer, the third Ti/TiN layer, and the Cu layer is formed. In such case, since thickness of the photoresist film has decreased by half the thickness of the Al layer, the photoresist film can finely be patterned. Moreover, since the metal line is formed with the Cu layer having more excellent electrical characteristic than the Al layer, high resistant to electro-migration characteristic can be obtained and a low electrical resistance value can be obtained, thereby improving packing density of the device and its yield and reliability.
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