Semiconductor Contact Over Source/Drain Structure Formation
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Solution Overview
Problem
Existing semiconductor manufacturing processes are inadequate for effective miniaturization and integration of circuits due to limitations in removing unreacted metal layers without damaging source/drain structures, leading to inefficiencies and potential corrosion.
Innovation Solution
A method involving the formation of a metallic layer over source/drain structures by reacting a metal layer with the substrate, followed by the use of a selective etching solvent containing H2SO4 and propylene carbonate to remove unreacted metal layers, which prevents corrosion and maintains the integrity of the source/drain structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used to remove unreacted metal layers, then metal layer removal is achieved, but source/drain structures suffer from corrosion and damage
Solution Approach 1:
An oxide layer is formed as an intermediary protective barrier between the etching solvent and the source/drain structures. The oxide layer is selectively removed only in contact holes, allowing the etching solvent to reach and remove unreacted metal layers without directly contacting and corroding the source/drain structures. This mediator approach resolves the contradiction by enabling precise metal removal while protecting critical structures.
Solution Approach 2:
The oxide layer is formed in advance before the etching process. This preliminary action creates a protective shield that prevents the etching solvent from damaging the source/drain structures during subsequent metal layer removal. The oxide layer is then selectively removed only where contacts are needed, allowing controlled etching without compromising structure integrity.
2Productivity
If device dimensions are reduced for miniaturization, then integration density increases, but manufacturing tolerances and process control become more difficult
Solution Approach 1:
The process applies different treatments to different locations: the oxide layer is formed uniformly across the surface but is selectively removed only in contact hole areas. The etching solvent then acts locally only where needed to remove unreacted metal layers. This local quality approach enables precise control at reduced dimensions by targeting specific areas rather than applying uniform processes across the entire structure.
Solution Approach 2:
The oxide layer serves as a spatial mediator that defines precise boundaries for where etching should occur. By controlling the formation and selective removal of this intermediary layer, the process achieves high dimensional control even as device sizes shrink, enabling accurate placement of contacts and interconnect structures at reduced dimensions.
3Productivity
If aggressive etching solvents are used to effectively remove metal layers, then metal removal efficiency increases, but source/drain structures become corroded
Solution Approach 1:
The oxide layer acts as a protective intermediary that allows the use of aggressive etching solvents for efficient metal layer removal while preventing these same solvents from corroding the source/drain structures. The oxide layer is selectively removed only in contact holes, enabling the aggressive solvent to act on metal layers without directly contacting and damaging the semiconductor structures.
Solution Approach 2:
The process converts the potentially harmful effect of aggressive etching solvents into a benefit by using the oxide layer to direct the solvent's action. The aggressive solvent efficiently removes unreacted metal layers where needed, while the oxide layer prevents it from harming the source/drain structures. The harmful corrosive action is thus converted into a beneficial selective removal process.
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 efficient removal of unreacted metal layers while protecting the source/drain structures, reducing the risk of corrosion and improving the manufacturing process efficiency, allowing for better integration and miniaturization of semiconductor devices.
Implementation Method 1
an etching solvent is used to remove the unreacted metal layer without damaging the source/drain structure
Implementation Method 2
annealing the metal layer to react with the source/drain structure
Data Source
AI summary
Methods for manufacturing semiconductor structures are provided. The method for manufacturing the semiconductor structure includes forming a fin structure protruding from a substrate and forming a source/drain structure over the fin structure. The method for manufacturing a semiconductor structure further includes forming a metallic layer over the source/drain structure and forming an oxide film on a sidewall of the source/drain structure. In addition, the oxide film and the metallic layer are both in direct contact with the source/drain structure.