Bottom-Up Contact Plug Formation Using Nitrided Metal Layers
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Solution Overview
Problem
The existing processes for forming source/drain contact plugs in integrated circuits face challenges in achieving seamless and efficient connections to source/drain regions and gate electrodes, often resulting in incomplete metal deposition and potential electrical leaks due to the limitations in current deposition methods.
Innovation Solution
The method involves depositing a metal layer, nitriding its surface to form a metal nitride layer, oxidizing it to remove excess portions, and then using the remaining nitride layers as a base for selective bottom-up deposition of metal, ensuring complete filling of contact openings without seams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional metal deposition methods are used to form contact plugs, then the deposition process is simple and fast, but the metal deposition is incomplete and seams are formed resulting in electrical leaks
Solution Approach 1:
The deposition process is segmented into multiple sequential steps: depositing a first metal layer, forming a metal nitride layer, selectively removing portions, and depositing a second metal layer. This segmentation allows each step to be optimized independently, ensuring complete filling of contact openings while maintaining process control
Solution Approach 2:
The metal nitride layer is formed in advance before the final metal deposition. This preliminary action creates a foundation layer that prevents seam formation during subsequent metal deposition, ensuring complete and seamless filling of contact openings
2Reliability
If metal layer is deposited to ensure complete filling of contact openings, then electrical integrity is improved, but the process requires multiple steps increasing manufacturing complexity
Solution Approach 1:
The metal nitride layer serves as an intermediary layer between the substrate and the final metal contact plug. This intermediary layer facilitates complete and seamless metal deposition, ensuring electrical integrity while providing a controlled interface for the deposition process
Solution Approach 2:
The process utilizes changes in material properties through nitridation and selective removal to control deposition behavior. By changing the chemical state of the metal layer (to nitride and back), the process achieves complete filling with precise control over metal deposition
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 the formation of seamless contact plugs that effectively connect to source/drain and gate regions, enhancing electrical integrity and reducing the risk of leaks by ensuring complete metal deposition and precise control over the deposition process.
Implementation Method 1
depositing a metal layer, nitridating a surface portion of the metal layer to form a metal nitride layer
Implementation Method 2
performing an oxidation process on the metal nitride layer to form a metal oxynitride layer
Implementation Method 3
filling a metallic material into the trench using a bottom-up deposition process to form a contact plug
Data Source
AI summary
A method includes etching a dielectric layer to form a trench in the dielectric layer, depositing a metal layer extending into the trench, performing a nitridation process on the metal layer to convert a portion of the metal layer into a metal nitride layer, performing an oxidation process on the metal nitride layer to form a metal oxynitride layer, removing the metal oxynitride layer, and filling a metallic material into the trench using a bottom-up deposition process to form a contact plug.