Copper Metallization Filling High-Aspect-Ratio Openings Without Barriers
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Solution Overview
Problem
Existing methods for forming metal structures in integrated circuits face challenges in filling high aspect ratio openings without voids and require diffusion barrier layers, especially at reduced feature sizes.
Innovation Solution
A method involving gas-induced metal migration is used to form a second metal structure over a first metal structure, utilizing oxidation and reduction reactions to fill openings without voids, eliminating the need for diffusion barrier layers and allowing lower temperature processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to form metal structures in high aspect ratio openings, then diffusion barrier layers are required, but this increases device complexity and processing temperature requirements
Solution Approach 1:
The patent removes the diffusion barrier layer from the conventional metal structure formation process. By using gas-induced metal migration, metal atoms can directly migrate through the dielectric material without requiring a diffusion barrier layer, thereby simplifying the device structure and reducing processing complexity while maintaining reliable metal structure formation
Solution Approach 2:
The patent changes the processing temperature parameter by enabling lower temperature processing. The gas-induced metal migration mechanism allows metal atoms to migrate at lower temperatures compared to conventional methods, eliminating the need for high temperature processing that would be required without diffusion barrier layers
2Reliability
If conventional metal deposition methods are used, then diffusion barrier layers are required, but this increases manufacturing steps and processing time
Solution Approach 1:
The patent eliminates the diffusion barrier layer and associated manufacturing steps. The gas-induced metal migration process directly forms metal structures without requiring intermediate barrier layer deposition, cleaning, and annealing steps, thereby reducing the total number of manufacturing operations and improving production efficiency
Solution Approach 2:
The patent employs a self-organizing mechanism where metal atoms automatically migrate along concentration gradients driven by gas exposure. This self-organizing behavior eliminates the need for complex controlled deposition processes and multiple processing steps, allowing the system to self-assemble the metal structure without extensive external intervention
3Reliability
If diffusion barrier layers are used, then metal structure formation is reliable, but processing temperature must be maintained at higher levels
Solution Approach 1:
The patent changes the temperature parameter by enabling lower temperature processing through gas-induced metal migration. The chemical potential gradient driven by gas exposure allows metal atoms to migrate and form structures at lower temperatures, eliminating the high temperature requirement that would otherwise be necessary to ensure reliable metal structure formation without diffusion barrier layers
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 method achieves void-free metal structure formation with improved density gradients and conductivity, enabling efficient integration into advanced IC manufacturing processes.
Implementation Method 1
A gas is provided that induces metal material from the metal structure to migrate into the opening... utilizing oxidation and reduction reactions
Implementation Method 2
utilizing oxidation and reduction reactions to fill openings without voids
Data Source
AI summary
A second metal structure such as a metal plug is formed over a first metal structure, such as a metal line, by causing metal material from the first metal structure to migrate into an opening in a dielectric layer over the first metal structure. The metal material, which may be copper, is of a type that undergoes a reduction in density as it oxidizes. Migration is induced using gases that alternately oxidize and reduce the metal material. Over many cycles, the metal material migrates into the opening. In some embodiments, the migrated metal material partially fills the opening. In some embodiments, the migrated metal material completely fills the opening.