Air-Gap Dielectric Layout for Dense Semiconductor Interconnects
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Solution Overview
Problem
The increasing complexity in manufacturing semiconductor devices leads to increased parasitic capacitance and power consumption due to capacitive coupling between adjacent conductive elements, especially in pattern-dense regions, which results in signal delay and performance issues.
Innovation Solution
A semiconductor device design that includes metal plugs over pattern-dense and pattern-loose regions with a dielectric layer, where a portion of the dielectric layer between metal plugs in the pattern-dense region is separated by an air gap, while in direct contact with the substrate in the pattern-loose region, reducing parasitic capacitance by forming spacers and using an energy removable structure to create and maintain the air gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If semiconductor devices are miniaturized to increase integration density, then functionality and integrated circuitry increase, but parasitic capacitance between adjacent conductive elements increases leading to higher power consumption and signal delay
Solution Approach 1:
The patent applies local quality by creating different dielectric configurations in different regions of the semiconductor device. Specifically, air gaps are introduced in pattern-dense regions where metal plugs are closely spaced, while pattern-loose regions maintain conventional dielectric structures. This localized modification reduces parasitic capacitance where it is most problematic (in dense regions) without unnecessarily altering structures in less critical areas.
Solution Approach 2:
The patent changes the dielectric parameter (capacitance) by replacing solid dielectric material with air gaps in specific regions. The air gap acts as a low-k dielectric structure with significantly reduced permittivity compared to conventional dielectric materials, thereby reducing parasitic capacitance between adjacent metal plugs in pattern-dense regions while maintaining other electrical parameters.
2Productivity
If semiconductor devices are miniaturized to increase integration density, then functionality and integrated circuitry increase, but parasitic capacitance between adjacent conductive elements increases resulting in signal delay
Solution Approach 1:
The patent applies local quality by creating different dielectric configurations in different regions of the semiconductor device. Specifically, air gaps are introduced in pattern-dense regions where metal plugs are closely spaced, while pattern-loose regions maintain conventional dielectric structures. This localized modification reduces parasitic capacitance where it is most problematic (in dense regions) without unnecessarily altering structures in less critical areas.
Solution Approach 2:
The patent changes the dielectric parameter (capacitance) by replacing solid dielectric material with air gaps in specific regions. The air gap acts as a low-k dielectric structure with significantly reduced permittivity compared to conventional dielectric materials, thereby reducing parasitic capacitance between adjacent metal plugs in pattern-dense regions while maintaining other electrical parameters.
3Loss of energy
If air gaps are introduced in pattern-dense regions to reduce parasitic capacitance, then power consumption and signal delay improve, but device complexity and manufacturing complexity increase
Solution Approach 1:
The patent applies preliminary action by forming the air gap structure during the dielectric layer deposition process itself. The dielectric layer is deposited conformally over the metal plugs and spacers, and subsequent etch-back or planarization steps automatically create the air gap region where the dielectric is removed. This preliminary formation of the air gap structure during standard manufacturing steps reduces the need for additional complex processing steps.
Solution Approach 2:
The patent uses spacers as intermediary structures that define the boundaries of the air gap regions. The spacers are formed on the sidewalls of metal plugs and serve as masks during dielectric deposition and etching processes. These intermediary spacer structures enable precise control of air gap formation without requiring direct patterning of the air gap regions themselves, simplifying the overall manufacturing process.
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 design effectively reduces parasitic capacitance, leading to improved device performance by decreasing power consumption and signal delay, enhancing overall semiconductor device functionality.
Implementation Method 1
A first portion of the dielectric layer between the first metal plug and the second metal plug is separated from the semiconductor substrate by an air gap
Data Source
AI summary
The present disclosure provides a method for preparing a semiconductor device. The method includes forming a first metal plug, a second metal plug, a third metal plug, and a fourth metal plug over a semiconductor substrate. The method also includes depositing a dielectric layer over the first metal plug, the second metal plug, the third metal plug, and the fourth metal plug. A first portion of the dielectric layer extends between the first metal plug and the second metal plug such that the first portion of the dielectric layer and the semiconductor substrate are separated by an airgap while a second portion of the dielectric layer extends between the third metal plug and the fourth metal plug such that the second portion of the dielectric layer is in direct contact with the semiconductor substrate.