Halogen-Based Diffusion Barrier for Semiconductor Dual Damascene Filling
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving conformal and efficient filling of metal interconnects in high-density structures due to limitations in current diffusion barrier and seed layer deposition techniques, particularly with the use of copper and low-k dielectric materials in dual damascene processes.
Innovation Solution
A method is introduced where a halogen-based precursor is used to deposit a diffusion barrier layer, allowing residual halogen to catalyze the growth of a subsequent metallic layer, such as copper, within the trench or via, utilizing atomic layer deposition (ALD) and chemical vapor deposition (CVD) techniques to ensure conformal and efficient filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional diffusion barrier deposition techniques are used, then the barrier layer can be deposited, but the subsequent metal layer growth is slow and contamination occurs
Solution Approach 1:
The patent converts the harmful residual halogen by-products from the diffusion barrier deposition process into a beneficial catalyst for metal layer growth. By intentionally retaining the halogen-containing by-products on the barrier layer surface instead of removing them, the invention achieves accelerated copper growth rates while maintaining material purity, as the halogen acts as a catalyst rather than a contaminant.
Solution Approach 2:
The residual halogen by-products serve as an intermediary substance that facilitates the deposition of the metal layer. The halogen species on the barrier layer surface act as catalytic sites that promote copper atom deposition and diffusion, enabling faster growth without compromising the integrity or purity of the final metal structure.
2Manufacturing precision
If multiple separate deposition steps are used for barrier and seed layers, then each layer can be optimized, but the process complexity and time increase
Solution Approach 1:
The patent merges the diffusion barrier deposition and metal seed layer deposition into a single integrated process sequence. The barrier layer is deposited using halogen-containing precursors, and the metal layer is deposited immediately afterward without intermediate cleaning or surface preparation steps, as the residual halogen serves as the catalyst. This consolidation reduces process complexity and time while maintaining conformal layer quality.
Solution Approach 2:
The invention maintains continuous useful action by eliminating idle or preparatory steps between barrier and metal layer deposition. The metal deposition begins immediately after barrier formation, utilizing the freshly deposited halogen-containing surface as the catalytic platform, thereby ensuring uninterrupted productive processing and reducing overall fabrication time.
3Manufacturing precision
If halogen based precursors are used for barrier deposition, then conformal coverage is achieved, but residual halogen causes contamination
Solution Approach 1:
The patent transforms the perceived harmful residual halogen contamination into a beneficial catalytic function. By retaining the halogen-containing by-products on the barrier layer surface, the invention achieves both conformal barrier coverage and accelerated metal growth, as the halogen species serve as catalytic sites rather than contaminants.
Solution Approach 2:
The invention changes the functional parameter of residual halogen from a contaminant to a catalyst. By adjusting the deposition conditions and retaining the halogen species on the surface, the process transforms the chemical role of the residual material, enabling it to promote metal layer growth rather than degrade material quality.
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 enables enhanced conformal filling of metal layers with improved growth rates and reduced contamination, maintaining the integrity of the diffusion barrier and interconnects, while avoiding issues with volatile by-products and material degradation.
Implementation Method 1
a halogen based pre-cursor is used during deposition of a first layer of material on a substrate
Implementation Method 2
residual halogen from the deposition is used to catalyse growth of a second layer of material on the first layer
Data Source
AI summary
There is described a method of fabricating a dual damascene structure for a semiconductor device. A halogen based pre-cursor is used during vapor deposition of a diffusion barrier layer in a trench or via formed in a substrate. Residual halogen from the deposition is allowed to remain on the barrier layer and is used to catalyse growth of a metal layer on the barrier layer to fill the trench or via.