BEOL Interconnect Barrier Structure for Lower RC Delay
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Solution Overview
Problem
The increasing resistance and capacitance between metal lines in advanced technology nodes of integrated circuits (ICs) due to smaller line widths and pitches lead to significant RC delay, limiting chip performance.
Innovation Solution
Implementing a semiconductor structure with multiple etch stop layers and barrier sublayers in the back-end-of-line (BEOL) processing to reduce undercut defects and enhance the interface between metal features, along with dopant-implanted regions in the dielectric layer to densify and pore-form specific areas, thereby reducing resistance and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If smaller line width and pitch are used to increase device speed, then channel length decreases and device speed increases, but resistance of metal lines increases and capacitance between neighboring metal lines increases
Solution Approach 1:
The patent applies local quality by creating dopant-implanted regions with different dopant concentrations at specific locations within the dielectric layer. High dopant concentration regions are placed near metal interconnect lines to reduce capacitance, while maintaining other areas with lower dopant concentration. This localized modification of dielectric properties reduces RC delay without affecting overall device performance.
Solution Approach 2:
The patent changes the physical and chemical parameters of the dielectric layer by implanting dopants that modify the dielectric constant and density in specific regions. This parameter change reduces the capacitance between metal lines and minimizes RC delay, allowing smaller line widths and pitches to be used without sacrificing signal integrity.
2Productivity
If smaller line width and pitch are used, then more interconnect lines can be packed, but resistance of metal lines increases
Solution Approach 1:
The patent creates localized dopant-implanted regions with high dopant concentration adjacent to metal interconnect lines. This local modification reduces the dielectric constant in these specific areas, thereby reducing capacitance and RC delay for high-density interconnects while maintaining reliable electrical connectivity.
3Reliability
If dopant concentration is increased to densify dielectric layer, then resistance decreases, but capacitance may increase if not controlled
Solution Approach 1:
The patent employs local quality by implementing spatially varying dopant concentrations within the dielectric layer. High dopant concentration regions are strategically placed near metal interconnects to reduce capacitance and improve electrical connectivity, while other regions maintain lower dopant concentrations to prevent excessive capacitance increase.
Solution Approach 2:
The patent introduces a dimensional aspect by creating vertically stratified dopant concentration profiles within the dielectric layer. Different dopant concentrations are applied at different depths and horizontal positions, allowing independent optimization of electrical connectivity and capacitance reduction in three-dimensional space.
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 proposed structure effectively minimizes RC delay and current leakage between neighboring metal lines, enhancing the performance of ICs by improving electrical connectivity and dielectric properties.
Implementation Method 1
dopant-implanted regions in the dielectric layer to densify and pore-form specific areas
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.