Bilayer Damascene Interconnect Liner for Low Contact Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor feature sizes scale down, copper contacts face challenges due to increased resistance from a larger fraction of the barrier wetting layer, poor diffusion barrier performance of alternative conductive materials, and non-uniform line resistance from polishing non-uniformity.
Innovation Solution
A bilayer liner structure is formed with a conductive liner wrapping around a conductor, featuring a manganese oxide barrier layer that fills gaps between grain boundaries of a metal oxide, improving adhesion and diffusion barrier performance, and a CMP process that maintains uniform contact height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper is used for contacts and interconnects, then electrical conductivity is improved, but diffusion into surrounding dielectric material occurs requiring a barrier wetting layer that increases contact resistance
Solution Approach 1:
The barrier structure is segmented into multiple functional layers: a copper barrier layer in direct contact with copper conductors to prevent diffusion, and a manganese oxide layer serving as a wetting layer to improve adhesion. This segmentation allows each layer to perform its specific function optimally without interfering with the other, resolving the contradiction between preventing diffusion and maintaining low contact resistance.
Solution Approach 2:
The manganese oxide layer acts as an intermediary between the copper barrier layer and the dielectric material. It provides a transition zone that improves adhesion and wetting while the copper barrier layer maintains the diffusion barrier function. This intermediary structure allows the system to achieve both low contact resistance and effective diffusion prevention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The bilayer liner structure reduces line resistance, maintains uniformity, and enhances adhesion while maintaining a high copper fraction, improving electrical performance and reducing capacitance.
Implementation Method 1
A barrier layer is at an interface between the conductive liner and the dielectric layer, including a manganese oxide and a metal oxide. The manganese oxide fills gaps between grain boundaries of the metal oxide.
Implementation Method 2
a CMP process that maintains uniform contact height
Data Source
AI summary
A device includes a dielectric layer and a conductor in the dielectric layer including a first conductive material. A conductive liner wraps around the conductor and includes a second conductive material. A barrier layer is at an interface between the conductive liner and the dielectric layer, including a first oxide and a second oxide.