Multi-Layer Contact Barrier Structure for Diffusion Control
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Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable semiconductor devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes decrease, leading to issues with processing and manufacturing efficiency.
Innovation Solution
The implementation of a semiconductor device structure that includes a barrier layer formed using multiple etching processes with specific thickness profiles and materials, such as titanium nitride, to prevent metal diffusion and maintain critical dimensions, combined with a contact structure that uses multiple barrier layers to ensure electrical connectivity and prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency and cost are improved, but fabrication process difficulty and reliability increase
Solution Approach 1:
The patent divides the single barrier layer into multiple barrier layers with different materials and thicknesses. Each layer serves a specific function: the first barrier layer (e.g., tungsten nitride) provides primary diffusion barrier, while the second barrier layer (e.g., titanium nitride) provides additional protection and adhesion. This segmentation allows the structure to maintain reliability at smaller dimensions by distributing the barrier function across multiple specialized layers.
Solution Approach 2:
The patent employs composite barrier structures combining different materials (e.g., tungsten nitride and titanium nitride, or cobalt nitride and tungsten silicide) with complementary properties. Each material contributes specific characteristics: some provide superior diffusion barrier properties, others provide better adhesion to underlying layers, and some offer enhanced mechanical strength. This composite approach maintains fabrication reliability while enabling continued scaling.
2Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency and cost are improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies different materials and thicknesses to different portions of the barrier structure. The first barrier layer may be thinner in regions where diffusion barrier is less critical, while the second barrier layer provides enhanced protection in regions requiring stricter dimensional control. This local differentiation optimizes the overall structure for both manufacturing precision and functionality.
Solution Approach 2:
The patent forms the multi-layer barrier structure before subsequent processing steps that may affect critical dimensions. By establishing the complete barrier structure early in the fabrication sequence, the structure serves as a stable foundation for subsequent operations, preventing dimensional changes and maintaining precision throughout the manufacturing process.
3Device complexity
If single barrier layer is used to prevent metal diffusion, then device structure is simple, but barrier effectiveness and reliability decrease
Solution Approach 1:
The patent segments the barrier function into multiple layers, each with specific thickness and material composition optimized for particular aspects of diffusion prevention. The first barrier layer (e.g., 5-15 nm tungsten nitride) blocks one type of metal diffusion, while the second barrier layer (e.g., 5-15 nm titanium nitride) blocks another type, providing comprehensive protection that a single layer cannot achieve.
Solution Approach 2:
The patent uses composite barrier layers combining materials with different diffusion barrier properties. For example, cobalt nitride provides excellent barrier against copper diffusion, while tungsten silicide provides superior barrier against other metals. The composite structure leverages the strengths of each material to achieve reliable diffusion prevention across multiple metal types.
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 enhances the reliability and efficiency of semiconductor device fabrication by maintaining critical dimensions, preventing short circuits, and improving the yield of barrier layers, thereby addressing the challenges of scaling down device sizes.
Implementation Method 1
a first metal nitride barrier layer over sidewalls of the contact layer... a second metal nitride barrier layer partially between the contact layer and the metal silicide layer
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes a contact layer over a metal silicide layer. The contact layer extends through a first dielectric structure. The semiconductor device structure includes a first metal nitride barrier layer over sidewalls of the contact layer. The first metal nitride barrier layer is directly adjacent to the first dielectric structure. The semiconductor device structure includes a second metal nitride barrier layer partially between the contact layer and the metal silicide layer and partially between the contact layer and the first metal nitride barrier layer. The metal silicide layer is below the first metal nitride barrier layer and the second metal nitride barrier layer.