Wcn / selective deposition of wcn barrier/adhesion layer for interconnect

Abstract

Provided are methods of forming diffusion barriers and adhesion layers for interconnects such as cobalt (Co) interconnects or ruthenium (Ru) interconnects. The methods involve selective deposition oftungsten carbon nitride (WCN) films on the oxide surfaces of a feature including a Co surface. The selective growth of WCN on oxide allows the contact resistance at an interface such as a Co-Co interface or a Co-Ru interface to be significantly reduced while maintaining good film coverage, adhesion, and / or barrier properties on the sidewall oxide surfaces.

Description

technical field [0001] The present invention relates generally to the field of semiconductors, and in particular to the selective deposition of WCN barrier / adhesion layers for interconnects. Background technique [0002] In semiconductor manufacturing, features may be filled with conductive material. For example, copper is used for back-end-of-line (BEOL) interconnects. However, copper interconnects are challenging to manufacture beyond the 7nm technology node. Deposition of copper interconnects typically involves first depositing a barrier layer. However, barrier materials that maintain integrity when the thickness shrinks below 2.5 nm have not yet been identified. As the line width reaches 10nm (at 5nm technology node), the barrier layer will consume 5nm line width and more than 50% of the line cross-section, so that for each technology node beyond 10nm, the resistance increases exponentially. Additionally, copper has an electron mean free path of about 39 nm. As a re...

AI Technical Summary

Problems solved by technology

However, barrier materials that maintain integrity when shrinking in thickness below 2.5 nm have yet to be identified

Images