T-Shape Metal Gate Void Prevention in Semiconductor Devices
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Solution Overview
Problem
The challenge in semiconductor device manufacturing is the formation of voids in the metal gate due to the overhang phenomenon during the gate trench filling process, which increases metal gate resistance and lowers device performance, especially as feature sizes decrease and aspect ratios of the gate trench become larger.
Innovation Solution
A semiconductor device manufacturing method is developed that forms a T-shape dummy gate structure and trench, allowing for precise filling of metal layers without overhang, using a T-shape metal gate structure with a work function adjusting layer and metal gate filling layer, and employing specific materials like TiN, TaN, Ti, Ta, W, Al, Cu, and high k materials to avoid void formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the gate trench width is reduced to achieve smaller device features, then the device scaling is improved, but the aspect ratio of the gate trench increases causing overhang and void formation during metal filling
Solution Approach 1:
The dummy gate structure is formed in advance before the actual gate trench formation. This preliminary structure allows for precise definition of the gate trench geometry, ensuring that the trench has optimized dimensions that prevent overhang during metal deposition while achieving the desired small device feature size.
Solution Approach 2:
The dummy gate structure serves as an intermediary element that facilitates the formation of the actual gate trench. By using this intermediate structure, the process achieves both small device dimensions and proper metal filling, as the dummy gate enables precise control of the gate trench geometry before the final metal deposition step.
2Manufacturing precision
If the gate trench aspect ratio is reduced to prevent overhang, then the metal filling completeness is improved, but the device feature size increases
Solution Approach 1:
The dummy gate is formed preliminarily to define the gate trench geometry before metal deposition. This allows the trench to have optimal aspect ratio for complete metal filling while the overall device feature size remains small, as the dummy gate structure enables precise geometric control.
Solution Approach 2:
The dummy gate acts as an intermediary that decouples the relationship between device feature size and gate trench aspect ratio. By using this intermediate structure, the process achieves both small device dimensions and favorable trench geometry for complete metal filling without overhang.
3Manufacturing precision
If the dummy gate height is increased to prevent overhang, then the metal filling completeness is improved, but the device complexity increases
Solution Approach 1:
The dummy gate structure is designed with specific local characteristics - it has a different height than the final gate structure. This local quality difference allows the dummy gate to prevent overhang during metal filling while the final device structure maintains simplicity with the standard gate height.
Solution Approach 2:
The dummy gate structure is temporarily created, serves its function of defining the gate trench geometry, and then is removed. This temporary structure enables complete metal filling without overhang, while the final device structure remains simple without the dummy gate components.
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 method effectively prevents voids in the metal gate, improving device performance by ensuring complete filling and reducing metal gate resistance, thus enhancing the overall performance of the semiconductor device.
Implementation Method 1
uses high k materials as gate insulation layer
Implementation Method 2
forming a T-shape metal gate structure by filling a metal layer in the T-shape gate trench
Data Source
AI summary
A method for manufacturing a semiconductor device is disclosed. The method comprises: forming a T-shape dummy gate structure on the substrate; removing the T-shape dummy gate structure and retaining a T-shape gate trench; forming a T-shape metal gate structure by filling a metal layer in the T-shape gate trench. According to the semiconductor device manufacturing method disclosed in the present application, the overhang phenomenon and the formation of voids are avoided in the subsequent metal gate filling process by forming a T-shape dummy gate and a T-shape gate trench, and the device performance is improved.