摘要 |
<p>An oxygen-free hydrogen plasma ashing process particularly useful for low-k dielectric materials based on hydrogenated silicon oxycarbide materials. The main ashing step includes exposing a previously etched dielectric layer to a plasma (48) of hydrogen (50) and optional nitrogen (54), a larger amount of water vapor (60), and a yet larger amount of argon (80) or helium. Especially for porous low-k dielectrics, the main ashing plasma additionally contains a hydrocarbon gas (84) such as methane. The main ashing may be preceded by a short surface treatment by a plasma of a hydrogen-containing reducing gas such as hydrogen and optional nitrogen.</p> |