Air Gap Structure for Semiconductor Metal Line Isolation
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Solution Overview
Problem
As semiconductor technologies advance, there is a need for smaller and more efficient packaging techniques to reduce capacitive coupling between metal lines in semiconductor devices, which existing low-K dielectric materials and air gaps do not adequately address, impacting device performance.
Innovation Solution
The implementation of a semiconductor device structure that includes multiple dielectric layers with air gaps between metal lines, formed through a process involving trench formation, barrier layer deposition, and conductive material filling, followed by planarization and air gap creation, reduces capacitive coupling by introducing a low-permittivity air gap that minimizes interference between adjacent metal lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-K dielectric materials are filled between adjacent metal lines, then capacitive coupling is reduced, but device size and integration density are limited
Solution Approach 1:
The patent introduces air gaps (porous structures) between metal lines instead of using solid low-K dielectric materials. The air gaps are formed by etching recesses into the dielectric layer and filling them with air or vacuum, achieving superior capacitive coupling reduction while maintaining compact device dimensions.
Solution Approach 2:
The patent creates a composite structure combining dielectric materials with air gaps. The dielectric layer provides mechanical support and electrical insulation, while the air gaps provide enhanced capacitive coupling reduction, achieving optimal performance through material combination.
2Reliability
If air gaps are employed to further reduce capacitive coupling, then performance characteristics are improved, but manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary actions by forming the air gaps at intermediate stages during the multi-layer metallization process. Rather than adding air gaps as a separate final step, the structure is prepared during dielectric layer formation and subsequent etching steps, integrating the air gap creation into the existing manufacturing flow.
Solution Approach 2:
The patent segments the dielectric layer into regions with and without air gaps, allowing different areas to serve different functions. Air gaps are selectively formed between specific metal lines where capacitive coupling is most problematic, while other regions maintain solid dielectric structures.
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 effectively reduces capacitive coupling, enhancing the performance and reliability of semiconductor devices by creating a low-permittivity air gap that improves the integration density and overall performance characteristics.
Implementation Method 1
In order to prevent interference such as capacitive coupling between two adjacent metal lines from having an impact on the overall performance of the semiconductor device, low-K dielectric materials may be filled between adjacent metal lines.
Implementation Method 2
low-K dielectric materials may be of a dielectric constant approximately equal to and less than 4.0. Furthermore, air gaps may be employed to further reduce capacitive coupling so as to improve the overall performance characteristics of the semiconductor device.
Data Source
AI summary
A device comprises a first protection layer over sidewalls and a bottom of a first trench in a first dielectric layer, a first barrier layer over the first protection layer, a first metal line in the first trench, a second protection layer over sidewalls and a bottom of a second trench in the first dielectric layer, a second barrier layer over the second protection layer, a second metal line in the first trench, an air gap between the first trench and the second trench and a third protection layer over sidewalls of a third trench in the first dielectric layer, wherein the first protection layer, the second protection layer and the third protection are formed of a same material.