Semiconductor Interconnect Structure for Lower RC Delay and Leakage
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Solution Overview
Problem
As integrated circuits (ICs) scale down, resistance-capacitance (RC) delay due to increased resistance and capacitance between metal lines limits chip speed, necessitating a solution to reduce RC delay and current leakage between neighboring metal lines.
Innovation Solution
The use of multiple etch stop layers and implanted regions in the dielectric layer, along with barrier layers, to reduce undercut defects and improve the dielectric constant of the material, thereby minimizing RC delay and current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the line width and pitch are reduced to increase device speed, then the channel length decreases and device speed increases, but the resistance of metal lines increases and capacitance between neighboring metal lines increases, leading to larger RC delay
Solution Approach 1:
The patent changes the physical and chemical parameters of the dielectric material by forming implanted regions with different dopant concentrations and types (e.g., phosphorus, boron) in the dielectric layer. This modifies the dielectric constant and electrical properties of the material to reduce capacitance and RC delay while maintaining the scaled-down geometry for high device speed
Solution Approach 2:
The patent uses composite dielectric structures combining multiple layers with different properties, including regions with and without implanted dopants, and interfaces between different dielectric materials. This composite structure allows optimization of both capacitance reduction and mechanical integrity
2Reliability
If multiple etch stop layers and implanted regions are added to reduce undercut defects and improve dielectric constant, then RC delay and current leakage are reduced, but the structural complexity increases
Solution Approach 1:
The patent segments the dielectric layer into multiple regions with different dopant concentrations and types, creating distinct functional zones. This segmentation allows precise control of electrical properties in different areas while using standardized fabrication processes for each segment
Solution Approach 2:
The patent performs dopant implantation and etch stop layer formation as preliminary actions during the dielectric layer formation process, before metal interconnect fabrication. This preliminary structuring prevents undercut defects and establishes optimal electrical properties early in the manufacturing sequence
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 approach effectively reduces RC delay and current leakage between metal lines, enhancing the performance of ICs by improving the structural integrity and electrical resistance of the semiconductor structure.
Implementation Method 1
The second dielectric layer includes an implanted region along a sidewall of the second dielectric layer
Implementation Method 2
barrier layers, to reduce undercut defects and improve the dielectric constant of the material, thereby minimizing RC delay and current leakage
Data Source
AI summary
A semiconductor structure includes a first dielectric layer, a first metal feature in the first dielectric layer, at least one etch stop layer on the first dielectric layer, a second dielectric layer on the at least one etch stop layer. The semiconductor structure further includes a first barrier sublayer on a sidewall of the second dielectric layer and the at least one etch stop layer, a second barrier sublayer on the first barrier sublayer and the first metal feature, and a second metal feature on the second barrier sublayer.