| abstract |
An improved sandwich layer of silicon dioxide layers for gap filling between metal lines. This is accomplished using a first layer formed in a PECVD process using TEOS and a fluorine-containing compound to give a barrier layer with a dielectric constant of less than 4.0, preferably approximately 3.5. Subsequently, an SACVD process is used with TEOS to form a gap filling layer. By appropriately choosing the thickness of the respective layers, one can adjust the dielectric to a value which is a combination of the dielectric constants of the two different layers, preferably giving a dielectric constant of approximately 3.6-3.7. |