Conductive Feature Sidewall Capping for Air-Gap Interconnects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in semiconductor manufacturing is to form conductive features with low resistance and high thermal stability while minimizing deformation and parasitic capacitance, which is exacerbated by the use of materials like ruthenium that are unstable at higher temperatures.
Innovation Solution
A capping layer is selectively deposited on the sidewalls of conductive features to protect them from deformation during high-temperature processes, combined with the formation of air gaps between neighboring features to reduce capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high-temperature processes are used to form conductive features, then thermal stability is improved, but material deformation increases
Solution Approach 1:
A capping layer is deposited on the sidewalls of conductive features before high-temperature processes to prevent deformation. This preliminary protective action allows the subsequent thermal processing to occur without compromising sidewall integrity, resolving the contradiction between achieving thermal stability and maintaining manufacturing precision.
2Productivity
If conductive features are formed with smaller dimensions to increase integration density, then device density is improved, but parasitic capacitance increases
Solution Approach 1:
Air gaps are introduced as intermediary spaces between neighboring conductive features. These air gaps act as electrical insulators that reduce parasitic capacitance between adjacent features, enabling higher integration density without the penalty of increased capacitive coupling.
3Reliability
If ruthenium material is used for conductive features, then electrical conductivity is improved, but thermal stability deteriorates
Solution Approach 1:
The capping layer serves as a protective cushion deposited beforehand on the ruthenium conductive features. This layer shields the thermally unstable ruthenium material from direct exposure to high-temperature processes, preserving both the electrical conductivity benefits of ruthenium and the thermal stability required for manufacturing.
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 results in conductive features with reduced resistance, improved thermal stability, and enhanced device density by minimizing sidewall deformation and parasitic capacitance, leading to improved reliability and yield.
Implementation Method 1
A capping layer is selectively deposited on the sidewalls of conductive features to protect them from deformation during high-temperature processes
Implementation Method 2
combined with the formation of air gaps between neighboring features to reduce capacitance
Data Source
AI summary
A method includes forming a conductive layer over a first dielectric layer; etching a recess in the conductive layer, wherein the recess exposes a top surface of the first dielectric layer; selectively depositing a capping layer on exposed sidewalls of the conductive layer within the recess; depositing a liner on the capping layer; forming a sacrificial material in the recess; and forming a second dielectric layer on the sacrificial material and on sidewalls of the recess; and after forming the second dielectric layer, performing a thermal process to remove the sacrificial material.