| 摘要 |
A first interlayer insulating film ( 3 ) having low dielectric constant is formed on an underlying insulating film ( 2 ) and a second interlayer insulating film ( 4 ) is formed on the first interlayer insulating film ( 3 ). Subsequently, a photoresist ( 5 ) having a pattern with openings above regions in which copper wirings are to be formed is formed on the second interlayer insulating film ( 4 ). Using the photoresist ( 5 ) as an etching mask, the second interlayer insulating film ( 4 ) and the first interlayer insulating film ( 3 ) are etched, to form a recess ( 6 ). Next, an ashing process using oxygen gas plasma ( 7 ) is performed, to remove the photoresist ( 5 ). This ashing process is performed under a plasma forming condition that the RF power is 300 W, the chamber pressure is 30 Pa, the oxygen flow is 100 sccm and the substrate temperature is 25° C. That provides a method of forming a dielectric film and a structure thereof, which allows suppression of a rise in dielectric constant of an interlayer insulating film, which is caused by a change of Si-C<SUB>n</SUB>H<SUB>2n+1 </SUB>bond into Si-OH bond in the film.
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