High Quality Low-k Spacer Deposited at Low Temperatures

Obtaining films with lower k (< 5) while still maintaining excellent etch properties and thermal stability has been a critical requirement for future nodes. A high quality low-k spacer deposited at low temperatures has been developed. The film has a low-k with very high break-down voltage which is maintained even after a RTA at 1000C. The film shows excellent resistance to typical wet etch chemistries, while also providing very good selectivity to Silicon Oxide dring dry etch. Another key aspect of spacer integration is that it must prevent underlying substrate oxidation upon exposure to an oxidative enviroment. This feature, and also the films own resistance to oxidation has been demonstrated. Films deposited using PECVD typically show varying film composiiton and quality on side-wall of features, on account of the direcionality of the deposting species and ions in the plasma. The current film shows good step coverage along with uniform film composiiton everywhere in a feature, which is a key feature for integration.