Carbon Dummy Gate for Semiconductor Device Manufacturing
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Solution Overview
Problem
The gate last process in semiconductor device manufacturing faces challenges in protecting the substrate from overetching, leading to increased defect density and degraded electrical performance, due to the use of ultra-thin oxide liners and etch blocking layers, which are difficult to form uniformly and are costly, making it inefficient for mass production.
Innovation Solution
A method involving a dummy gate stack structure made of carbon-based materials, such as amorphous carbon thin films, which provides selective etching and eliminates the need for additional oxide liners or etch blocking layers, allowing for the formation of a gate trench without substrate overetching, thereby simplifying the process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oxide liner and/or etch blocking layer is formed on the substrate to protect it from overetching, then the substrate is protected from overetching, but the process complexity increases and manufacturing cost increases
Solution Approach 1:
A dummy gate structure made of carbon-based material is introduced as an intermediary protective layer during the etching process. This dummy gate serves as a sacrificial mask that protects the substrate from overetching while being easily removable, replacing the need for complex oxide liner and etch blocking layer structures.
Solution Approach 2:
The dummy gate structure is designed as a disposable sacrificial element that is removed after serving its protective function. This approach is more cost-effective than forming ultra-thin oxide liners and etch blocking layers, as it uses simple carbon-based materials that are easier and cheaper to deposit and remove.
2Reliability
If an oxide liner and/or etch blocking layer is formed on the substrate to protect it from overetching, then the substrate is protected from overetching, but the manufacturing cost increases
Solution Approach 1:
The dummy gate structure is designed as a disposable sacrificial element that is removed after serving its protective function. This approach is more cost-effective than forming ultra-thin oxide liners and etch blocking layers, as it uses simple carbon-based materials that are easier and cheaper to deposit and remove.
Solution Approach 2:
The invention changes the material parameter of the dummy gate from traditional silicon-based materials to carbon-based materials. This parameter change enables better etching selectivity and eliminates the need for additional protective layers, thereby reducing manufacturing costs while maintaining substrate protection.
3Ease of manufacture
If a dummy gate made of silicon-based materials is used, then the dummy gate can be formed easily, but the substrate is overetched during etching of the dummy gate
Solution Approach 1:
The invention changes the material parameter of the dummy gate from traditional silicon-based materials to carbon-based materials. This parameter change enables better etching selectivity and eliminates the need for additional protective layers, thereby reducing manufacturing costs while maintaining substrate protection.
Solution Approach 2:
The dummy gate is formed as a composite structure with a carbon-based material layer that provides etching selectivity. This composite approach maintains the ease of dummy gate formation while preventing substrate overetching through the unique properties of carbon-based materials.
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 ensures reliable device performance by preventing substrate overetching, simplifies the manufacturing process, and reduces costs by eliminating the need for additional protective layers, while maintaining high efficiency in the gate last process.
Implementation Method 1
A method involving a dummy gate stack structure made of carbon-based materials, such as amorphous carbon thin films, which provides selective etching
Data Source
AI summary
The present invention discloses a method for manufacturing a semiconductor device, comprising the steps of: forming a dummy gate stack structure on a substrate, wherein the dummy gate stack structure contains carbon-based materials; forming source/drain region in the substrate on both sides of the dummy gate stack structure; performing etching to remove the dummy gate stack structure until the substrate is exposed, resulting in a gate trench; and forming a gate stack structure in the gate trench. In accordance with the method for manufacturing a semiconductor device of the present invention, the dummy gate made of carbon-based materials is used to substitute the dummy gate made of silicon-based materials, then no oxide liner and/or etch blocking layer needs be added while the dummy gate is removed by etching in the gate last process, thus the reliability of device is ensured while the process is simplified and the cost is reduced.