Conformal Liner Repair Layer for Damascene Interconnects
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Solution Overview
Problem
Conventional copper-dielectric interconnect structures in integrated circuits face issues with signal propagation delay and liner discontinuities due to sputter etch preclean processes, which lead to increased resistance and capacitance, and potential metal diffusion into dielectric materials, compromising the integrity of the interconnect structure.
Innovation Solution
The implementation of a conformal liner repair layer, typically made of cobalt-containing materials, bridges discontinuities in the liner layer, ensuring continuous coverage and preventing metal diffusion, thereby maintaining the integrity of the dielectric material and reducing signal propagation delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If sputter etch preclean processes are used to clean the dielectric material surface, then signal propagation delay is reduced, but liner discontinuities occur leading to metal diffusion into dielectric materials
Solution Approach 1:
A liner repair layer is deposited beforehand to prevent metal diffusion into the dielectric material. This preliminary protective action ensures that even if the initial liner is discontinuous due to sputter etch damage, the underlying dielectric material remains protected from copper diffusion.
Solution Approach 2:
The liner repair layer acts as a cushioning barrier deposited in advance to compensate for potential liner discontinuities. This additional protective layer ensures continuous coverage and prevents harmful metal diffusion while allowing the use of aggressive sputter etch preclean processes.
2Ease of manufacture
If conventional liner layers are used without repair, then manufacturing process is simpler, but metal diffusion into dielectric materials compromises interconnect integrity
Solution Approach 1:
The liner structure is segmented into multiple functional layers: an initial liner layer deposited during standard damascene processing, and a subsequent liner repair layer. This segmentation allows each layer to perform its specific function while maintaining overall process efficiency and interconnect integrity.
Solution Approach 2:
The interconnect structure employs a composite liner system combining the initial liner material with a repair layer material, creating a more robust multi-layer barrier structure that prevents metal diffusion while maintaining compatibility with existing manufacturing processes.
3Speed
If copper metal is used to reduce resistance, then signal propagation delay is reduced, but adhesion and diffusion control require additional liner layers
Solution Approach 1:
The liner repair layer serves multiple functions simultaneously: it provides adhesion support for the copper metal, acts as a diffusion barrier to prevent copper from migrating into the dielectric material, and ensures continuous coverage over discontinuities. This multi-functionality reduces the need for additional separate layers.
Solution Approach 2:
The deposition parameters of the liner repair layer are optimized to achieve the desired thickness and coverage properties. By controlling deposition conditions, the repair layer can be tailored to provide adequate protection while minimizing overall structure complexity and maintaining signal propagation performance.
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 conformal liner repair layer effectively addresses the discontinuities caused by sputter etch preclean processes, ensuring reliable and efficient signal transmission by maintaining a continuous barrier and reducing the risk of metal diffusion into dielectric materials, thus enhancing the performance and reliability of the interconnect structure.
Implementation Method 1
a conformal liner repair layer of a conductive material bridges the discontinuities in the liner layer
Implementation Method 2
discontinuities in the liner layer caused by sputter etch preclean processes
Data Source
AI summary
Design structure embodied in a machine readable medium for designing, manufacturing, or testing a design. The design structure includes an interconnect structure with a liner formed on roughened dielectric material in an insulating layer and a conformal liner repair layer bridging that breaches in the liner. The conformal liner repair layer is formed of a conductive material, such as a cobalt-containing material. The conformal liner repair layer may be particularly useful for repairing discontinuities in a conductive liner disposed on roughened dielectric material bordering the trenches and vias of damascene interconnect structures.