Interconnect Metallization Sidewall Oxidation to Prevent Collapse
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Solution Overview
Problem
As semiconductor devices shrink in size, the reduced spacing and size of metallization structures in the interconnect layer lead to voids and discontinuities, increasing contact resistance and the risk of electrical disconnects, exacerbated by the use of liners that worsen gap-filling performance.
Innovation Solution
Forming a layer of conductive material above interconnect structures, etching it to define metallization structures, and sealing gaps with low-k dielectric plugs, while oxidizing exposed sidewalls to create metal-oxide liners for increased mechanical strength and low electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If metallization structures are formed with reduced spacing and size to shrink semiconductor device size, then device miniaturization is achieved, but voids and discontinuities increase leading to higher contact resistance
Solution Approach 1:
The patent changes the material parameter of the liner from conventional metal liners to metal-oxide liners. This parameter change fundamentally alters the gap-filling properties, allowing the liner to conformally fill narrow spaces without creating voids or discontinuities, thus maintaining low contact resistance despite reduced metallization spacing
Solution Approach 2:
The patent uses composite material structure consisting of metal-oxide liners combined with conductive fill material. The metal-oxide liner provides excellent gap-filling and adhesion properties, while the conductive fill material provides low resistance, creating a composite structure that solves both the miniaturization and reliability challenges
2Strength
If liners are used in metallization structures, then adhesion and structural support are improved, but gap-filling performance deteriorates leading to voids and discontinuities
Solution Approach 1:
The patent transforms the liner material parameter from metal to metal-oxide, which fundamentally changes the deposition characteristics and gap-filling behavior. The metal-oxide material enables conformal filling of narrow gaps while maintaining structural integrity, resolving the contradiction between structural support and gap-filling performance
3Ease of manufacture
If conventional metallization structures are used, then manufacturing process is simple, but signal propagation speed is limited due to higher RC time constant
Solution Approach 1:
The patent changes the liner material parameter to metal-oxide, which provides lower electrical resistance. This parameter change reduces the RC time constant of the metallization structure, enabling faster signal propagation while maintaining a relatively simple manufacturing process through conformal deposition techniques
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 reduces contact resistance, enables faster signal propagation, and maintains structural integrity of metallization structures, achieving a low RC time constant and improved switching speeds.
Implementation Method 1
performing an oxidation operation to oxidize sidewalls of the plurality of conductive structures
Data Source
AI summary
A layer of conductive material is formed above a bottom-most layer of interconnect structures in an interconnect layer of a semiconductor device, and the layer of conductive material is etched to define the bottom-most layer of metallization structures from the layer of conductive material. To reduce the likelihood of collapse of the free-standing metallization structures, the exposed sidewall surfaces of the free-standing metallization structures may be oxidized to form metal-oxide sidewalls for the free-standing metallization structures. The metal-oxide sidewalls may be formed using a self-aligned oxidation technique that specifically targets the sidewalls of the free-standing metallization structures for oxidation. The metal-oxide sidewalls may be formed of a metal-oxide material that increases the mechanical strength of the free-standing metallization structures, which enables the free-standing metallization structures to resist collapsing.