Isolation-Lined Interconnect Structure for Low-k RC Delay Trade-Off
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Solution Overview
Problem
Conventional methods using low-k dielectric materials for isolation layers in semiconductor devices face a trade-off between porosity and dielectric constant, leading to increased RC delay and unreliable isolation, which degrades device performance.
Innovation Solution
Implementing an isolation dielectric layer that extends along the sidewalls and lower boundaries of conductive structures within the low-k dielectric material to enhance isolation, minimizing the dielectric constant without compromising on porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If low-k dielectric material is used to form the isolation layer, then the RC delay is reduced, but the porosity increases causing unreliable isolation and contamination
Solution Approach 1:
The isolation layer is segmented into multiple functional layers: a first isolation layer made of low-k dielectric material with porosity of 30-70% for reducing RC delay, and a second isolation layer made of non-porous dielectric material for providing reliable isolation and contamination protection. This segmentation allows each layer to optimize for its specific function.
Solution Approach 2:
The isolation structure uses a composite material system combining porous low-k dielectric material (such as silsesquioxane-based materials) with non-porous dielectric material. The porous material provides low dielectric constant while the non-porous material provides structural integrity and isolation reliability, creating a composite structure that leverages the advantages of both materials.
2Loss of time
If the dielectric constant is minimized to reduce RC delay, then the porosity increases, but the isolation ability deteriorates
Solution Approach 1:
The isolation function is segmented between two layers: the first isolation layer with high porosity (30-70%) provides low dielectric constant to reduce RC delay, while the second isolation layer with low porosity provides dense isolation to prevent parasitic coupling. This segmentation resolves the contradiction by assigning different isolation functions to different layers.
Solution Approach 2:
Different regions of the isolation structure have different porosity characteristics optimized for their specific functions. The first isolation layer has high porosity locally optimized for electrical performance (low RC delay), while the second isolation layer has low porosity locally optimized for isolation performance (preventing parasitic coupling).
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 solution effectively reduces RC delay and improves isolation, ensuring reliable performance by optimizing the dielectric constant while addressing porosity issues in low-k dielectric materials.
Implementation Method 1
an isolation dielectric layer is formed along the sidewalls and partially or fully along the lower boundary of conductive structures within a low-k dielectric material, further isolating conductive structures
Implementation Method 2
a low-k dielectric material has been used to form the isolation layer because its low dielectric constant is useful in reducing the RC delay that is positively proportional to the dielectric constant
Data Source
AI summary
A semiconductor device includes: a first conductive structure that comprises a first portion having sidewalls and a bottom surface, wherein the first conductive structure is embedded in a first dielectric layer; and an isolation layer comprising a first portion and a second portion, wherein the first portion of the isolation layer lines the sidewalls of the first portion of the first conductive structure, and the second portion of the isolation layer lines at least a portion of the bottom surface of the first portion of the first conductive structure.