Suspended Fin Structure for Multi-Gate MOSFET Processing
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Solution Overview
Problem
The increasing miniaturization of semiconductor devices poses challenges in manufacturing Multi-gate MOSFETs due to the varying heights of fin-shaped structures, leading to issues like over-polishing or insufficient polishing of gates, which complicates the processing and affects electrical requirements.
Innovation Solution
A semiconductor process that forms a suspended part in a fin-shaped structure by removing parts of the bottom part to create a through hole, allowing a gate to surround the suspended part, resulting in a semiconductor structure with four gate channels, enabling adjustment of the depth and width to meet different electrical requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the heights of fin-shaped structures are varied to meet different electrical requirements, then the electrical performance is improved, but the processing difficulty increases leading to over-polishing or insufficient polishing of gates
Solution Approach 1:
The fin-shaped structure is segmented into different height levels by removing portions of the bottom part, creating suspended sections at specific heights. This segmentation allows different regions of the same fin structure to have different effective heights, enabling varied electrical characteristics while maintaining a uniform overall structure that can be processed consistently
Solution Approach 2:
The invention transitions from varying the overall height dimension of entire fin structures to creating suspended sections within the vertical dimension. By removing material from the bottom part to create through holes and suspended sections, the effective gate channel height can be varied without changing the top surface level, adding complexity to the vertical dimension while maintaining uniformity in other dimensions for easier processing
2Adaptability or versatility
If the heights of fin-shaped structures are varied to meet different electrical requirements, then the electrical performance is improved, but the number of processing problems increases
Solution Approach 1:
Different sections of the fin-shaped structure are given different local qualities by selectively removing the bottom part in specific regions. This creates suspended sections with different effective heights only where needed, while other regions maintain the standard structure. This localized modification allows tailored electrical characteristics without compromising the overall reliability of the manufacturing process
3Productivity
If the gate surrounds the suspended part to form four gate channels, then the current between source and drain is increased, but the manufacturing process complexity increases
Solution Approach 1:
The bottom part of the fin-shaped structure is removed in advance to create the suspended configuration before the gate formation process. This preliminary action establishes the four-channel geometry early in the manufacturing sequence, allowing the gate material to be deposited uniformly around all four channels in a single continuous process, rather than requiring multiple separate gate formation steps
Data Source
AI summary
A semiconductor structure includes a fin-shaped structure and a gate. The fin-shaped structure is located in a substrate, wherein the fin-shaped structure has a through hole located right below a suspended part. The gate surrounds the suspended part. Moreover, the present invention also provides a semiconductor process including the following steps for forming said semiconductor structure. A substrate is provided. A fin-shaped structure is formed in the substrate, wherein the fin-shaped structure has a bottom part and a top part. A part of the bottom part is removed to form a suspended part in the corresponding top part, thereby forming the suspended part over a through hole. A gate is formed to surround the suspended part.