Integrated Barrier Nucleation Layer for Low Resistance Interconnects
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Solution Overview
Problem
High contact resistance in interconnection structures of semiconductor integrated circuits affects the electrical reliability and performance of fabricated circuits, despite the use of low-resistance conductive materials.
Innovation Solution
A conductive structure is created with a substrate, a dielectric layer, and a low resistive layer formed by reacting a first and second transition layer to produce a carbonitride of a metal material, which serves as both a barrier and nucleation layer, eliminating the need for extra barrier and nucleation layers, and is filled with a metal bulk to reduce contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive materials are used to form contact plugs and interconnection structures, then the materials have low resistance, but the contact resistance between conductive layers becomes high, deteriorating electrical characteristics
Solution Approach 1:
The patent combines the barrier layer and nucleation layer into a single integrated layer structure. The first transition layer serves as the barrier layer preventing metal diffusion, while the second transition layer serves as the nucleation layer for metal bulk formation. This merging eliminates the interface between separate barrier and nucleation layers, thereby reducing contact resistance and improving electrical reliability.
Solution Approach 2:
The patent uses composite transition layer structures comprising different materials with specific properties. The first transition layer (barrier layer) uses materials such as titanium nitride or tantalum oxide to prevent diffusion, while the second transition layer (nucleation layer) uses materials like tungsten or cobalt to facilitate metal bulk formation. This composite structure optimizes both diffusion prevention and low contact resistance simultaneously.
2Reliability
If separate barrier layer and nucleation layer are used in conductive structure, then proper barrier and nucleation functions are achieved, but the thickness of the whole conductive structure increases
Solution Approach 1:
The patent merges the barrier layer and nucleation layer into a closely integrated two-layer structure where the first transition layer (barrier) and second transition layer (nucleation) are deposited sequentially with minimal interface thickness. This integration maintains both barrier and nucleation functions while minimizing the overall thickness compared to conventional structures with thicker separate layers and multiple interfaces.
Solution Approach 2:
The patent optimizes the thickness parameters of the transition layers to achieve functional equivalence with thinner overall structure. The barrier layer is maintained at minimal thickness sufficient for diffusion prevention, while the nucleation layer is optimized for efficient metal bulk formation. This parameter optimization reduces the total conductive structure thickness while preserving essential functions.
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 reduces the thickness and contact resistance of the conductive structure, enhancing the performance of the final fabricated circuits by integrating the method into both FEOL and BEOL processes.
Implementation Method 1
a treatment is performed to react the first transition layer and the second transition layer to form a low resistive layer including a carbonitride of the first metal material
Data Source
AI summary
A conductive structure includes a substrate including a first dielectric layer formed thereon, at least a first opening formed in the first dielectric layer, a low resistive layer formed in the opening, and a first metal bulk formed on the lower resistive layer in the opening. The first metal bulk directly contacts a surface of the first low resistive layer. The low resistive layer includes a carbonitride of a first metal material, and the first metal bulk includes the first metal material.