Phosphorus-Doped Interconnects for Leakage and Electromigration
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Solution Overview
Problem
Dual-damascene interconnect structures in semiconductor integrated circuits face challenges with fragile ultra-low-k dielectric materials and metal impurities leading to degraded interconnect resistance and capacitance, as well as electromigration issues.
Innovation Solution
Incorporating a phosphorus-doped layer into conductive paths and dielectric regions using a gas cluster ion beam (GCIB) process to getter metal impurities and reduce electromigration, thereby improving the reliability of copper and dielectric features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If ultra-low-k dielectric materials are used to reduce capacitance, then interconnect capacitance is reduced, but the dielectric material becomes fragile and prone to damage
Solution Approach 1:
A phosphorus-doped layer is introduced as an intermediary between the copper interconnect and the ultra-low-k dielectric material. This intermediate layer protects the fragile dielectric from damage during CMP and other processing steps while allowing the ultra-low-k material to maintain its low capacitance properties.
Solution Approach 2:
The phosphorus-doped layer is formed prior to depositing the ultra-low-k dielectric material, preparing the surface in advance to prevent dielectric damage during subsequent processing steps such as chemical-mechanical polishing.
2Loss of energy
If copper is used as the interconnect material, then interconnect resistance is reduced, but electromigration becomes a significant reliability issue
Solution Approach 1:
The electrical and mechanical parameters of the copper interconnect are modified by doping with phosphorus. This changes the copper's properties to reduce electromigration while maintaining its low resistance characteristics, achieving both improved conductivity and enhanced reliability.
3Ease of manufacture
If metal impurities are present in the interconnect structure, then manufacturing is simplified, but electrical leakage and line-to-line breakdown increase
Solution Approach 1:
The phosphorus-doped layer serves as a gettering layer that attracts and traps metal impurities, preventing them from causing electrical leakage or breakdown. This intermediary layer maintains electrical integrity without adding significant manufacturing complexity.
Solution Approach 2:
The phosphorus-doped layer converts the potential harm of metal impurities into a beneficial effect by using the impurities as gettering sites, thereby protecting the interconnect structure from electrical leakage and breakdown.
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
This approach enhances the reliability of semiconductor devices by minimizing line-to-line breakdown and electrical leakage, improving device characteristics and reducing electromigration in copper lines.
Implementation Method 1
Incorporating a phosphorus-doped layer into conductive paths and dielectric regions using a gas cluster ion beam (GCIB) process
Data Source
AI summary
Embodiments of methods for improving electrical leakage performance and minimizing electromigration in semiconductor devices are generally described herein. Other embodiments may be described and claimed.