Maybe your PECVD chamber has a loadlock? If the loadlock can load Cu sample
and pump to high vaccum, then heat up. This theoretically will prevent Cu
oxidizing. Otherwise, like the PECVD we have: it is manually loaded and
never go to high vacuum (1mt only), at high T, the residue air will
oxidize cu easily. But maybe you have a fancy machine?

Better to cover Cu with TiW cap layer, then OK.

> Cu will get oxidized in the air to form very thin CuO. In SiN PECVD, you
> will have only 3SiH4 + 2NH3 +N2 ==> Si3N4 (film) + 9H2. There is no O2.
> People have been using SiN as Cu diffusion barrier in advanced Cu CMOS
> technology for very long time.