| 摘要 |
A lower carbon film as a provisional film, a lower SiO2 film and an upper carbon film are formed, and then trenches having a wiring pattern are formed in the upper carbon film. Next, contact holes are formed through the lower carbon film and the lower SiO2 film. Then, wires and plugs are formed by filling in the trenches and contact holes with a barrier metal film and a Cu alloy film. After these process steps are repeatedly performed several times, a dummy opening is formed to extend downward through the uppermost SiO2 film. Thereafter, the carbon films are removed by performing ashing with oxygen introduced through the dummy opening. As a result, gas layers are formed to surround the wires and plugs. In this manner, a highly reliable gas-dielectric interconnect structure can be obtained by performing simple process steps.
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