Semiconductor Vertical Structure Uniformity via Layered Masks
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Solution Overview
Problem
In semiconductor manufacturing using metal-oxide-semiconductor (MOS) technology, the etching process for forming vertical structures in field effect transistors (FETs) results in non-uniform heights due to consumption of the vertical structure during processing, leading to inconsistent device performance.
Innovation Solution
A method involving the sequential formation of oxide and nitride layers, followed by polysilicon patterns, and sacrificial layers, with spacers and masks to control etching and pattern transfer, ensuring uniformity and precision in forming vertical structures and epitaxial layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry etching or wet etching is used to form vertical structures, then the vertical structures can be formed, but the height of the vertical structures becomes non-uniform due to material consumption during etching
Solution Approach 1:
The patent applies preliminary action by forming protective oxide layers and nitride layers on the vertical structures before the etching process. These layers are deposited in advance to prevent material consumption during subsequent etching steps, ensuring uniform height of the vertical structures after processing.
Solution Approach 2:
The patent uses oxide layers and nitride layers as intermediary protective barriers between the vertical structure material and the etching environment. These intermediary layers protect the underlying vertical structures from direct exposure to etchants, preventing unwanted material removal and maintaining dimensional accuracy.
2Manufacturing precision
If multiple oxide and nitride layers are formed sequentially with polysilicon patterns and masks, then precise control over layer formation is achieved, but the manufacturing process complexity increases
Solution Approach 1:
The patent segments the manufacturing process into distinct sequential steps: forming oxide layers, forming nitride layers, depositing polysilicon, creating masks, and performing pattern transfers. Each step is independently controlled and optimized, allowing precise manipulation of each layer while maintaining overall process manageability through clear separation of functions.
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 fabrication of semiconductor devices with uniform vertical structures and epitaxial layers, improving device performance and consistency by minimizing material loss during etching and ensuring precise control over layer formation.
Implementation Method 1
forming a first oxide layer on a substrate, forming a first nitride layer on the first oxide layer. The method further includes forming a second oxide layer on the first nitride layer, and forming a second nitride layer on the second oxide layer
Implementation Method 2
removing a portion of the first oxide layer, first nitride layer, second oxide layer, and second nitride layer using the plurality of polysilicon patterns as a mask
Data Source
AI summary
A method for manufacturing a semiconductor is provided. A first oxide layer is formed on a substrate. A first nitride layer is formed on the first oxide layer. A second oxide layer, a second nitride layer are formed on the first nitride layer. A polysilicon layer is formed on the second nitride layer. A third nitride layer is formed on the polysilicon layer. One or more first patterns are formed on the third nitride layer. The one or more first patterns are transferred to the polysilicon layer to form one or more patterned polysilicon layer. A portion of the first oxide layer, first nitride layer, second oxide layer, and second nitride layer are removed using the one or more patterned polysilicon layer as a first mask.