Interconnect Air Gap Structure for Lower RC Delay
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Solution Overview
Problem
As semiconductor feature sizes decrease, the distance between interconnect metal features increases resistance-capacitance (RC) delay and electronic signal interference, necessitating improved isolation methods.
Innovation Solution
Incorporation of air gaps among interconnect metal features using a plasma treatment process to form capping portions that isolate conductive features in semiconductor devices, reducing line-to-line capacitance and RC time delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes are decreased to increase integration density, then productivity and device functionality are improved, but resistance-capacitance delay and electronic signal interference increase
Solution Approach 1:
The patent applies local quality by introducing air gaps specifically in the regions between adjacent interconnect metal features, while maintaining the original dielectric material in other regions. This localized modification reduces line-to-line capacitance where needed without affecting the overall interconnect structure or requiring changes to feature sizes, thus improving signal integrity while preserving integration density.
Solution Approach 2:
The patent introduces an intermediary air gap structure between the interconnect metal features and the surrounding dielectric material. This air gap acts as a mediator that electrically isolates adjacent metal lines, reducing capacitive coupling and signal interference without requiring increased spacing between features, thereby maintaining productivity while improving reliability.
2Reliability
If air gaps are incorporated to reduce line-to-line capacitance, then signal interference is reduced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent employs preliminary action by forming the air gap structure during the dielectric layer formation process itself, rather than as a separate subsequent step. The air gaps are created by patterning the dielectric layer to include void spaces, and then filling selected regions with conductive material. This integration of air gap formation into the existing manufacturing flow minimizes additional process steps and reduces device complexity.
3Reliability
If air gaps are incorporated to reduce RC delay, then performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies self-service by utilizing the self-aligning nature of the conformal deposition process. The conductive material is deposited conformally on the dielectric layer, automatically forming precise air gap structures that align with the underlying metal features. This self-aligned approach eliminates the need for separate alignment steps and reduces manufacturing precision requirements, as the process automatically maintains the correct geometric relationships.
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 plasma treatment process effectively forms air gaps with a low dielectric constant, minimizing parasitic capacitance and enhancing semiconductor performance by reducing RC delay and signal interference.
Implementation Method 1
subjecting the dielectric spacers and the dielectric portions to a plasma treatment process such that the dielectric spacers and the dielectric portions are deformed to form a plurality of capping portions
Data Source
AI summary
A method for manufacturing a semiconductor device includes: forming on a substrate, a structure including a plurality of dielectric spacers and a plurality of dielectric portions that are disposed to form a plurality of recesses, such that each of the recesses is formed between a corresponding one of the dielectric spacers and a corresponding one of the dielectric portions; and subjecting the dielectric spacers and the dielectric portions to a plasma treatment process such that the dielectric spacers and the dielectric portions are deformed to form a plurality of capping portions to cap the recesses, respectively, so as to form a plurality of air gaps.