Variable Height FinFETs for Driving Capability Control
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Solution Overview
Problem
FinFETs face design challenges due to fixed fin heights, limiting the variation of conductive currents in integrated circuits, as they only provide one parameter (length) for controlling conductive and cutoff currents, whereas conventional MOSFETs offer two parameters (channel width and length).
Innovation Solution
A semiconductor device and manufacturing method that allow for the formation of fins with different heights on the same semiconductor layer, enabling devices with varied channel widths and driving capabilities by selectively patterning and etching the semiconductor layer to different depths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fins are formed with the same height to facilitate photolithographic patterning, then manufacturing ease is improved, but device versatility deteriorates because conductive current cannot be varied
Solution Approach 1:
The patent divides the semiconductor layer into multiple regions with different etching depths, creating fins of different heights. This segmentation allows each fin region to have independent height control while maintaining overall manufacturing feasibility through standardized photolithographic processes applied to each segmented region.
Solution Approach 2:
The patent applies local quality by creating spatial variation in fin height across different regions of the semiconductor layer. Each local region has customized fin height properties tailored to specific device requirements, while the overall structure maintains manufacturing consistency through region-by-region processing.
2Manufacturing precision
If fin height is fixed to simplify manufacturing, then manufacturing precision is improved, but device functionality deteriorates due to limited control parameters
Solution Approach 1:
The patent transitions from two-dimensional fin structures (uniform height) to three-dimensional structures with variable heights. This dimensional change enables additional control parameters while maintaining manufacturing precision through controlled etching processes that achieve different depths in different regions.
Solution Approach 2:
The patent introduces dynamic variability in fin height across different device regions, allowing the structure to adapt to different functional requirements. This dynamic approach enables continuous adjustment of conductive current characteristics while maintaining precise control over each fin's dimensions.
3Device complexity
If all fins have the same dimensions, then manufacturing complexity is reduced, but device performance deteriorates due to identical driving capabilities
Solution Approach 1:
The patent changes the height parameter of fins across different regions to achieve varied driving capabilities. By modifying this single geometric parameter while maintaining other dimensions, the patent achieves device performance differentiation without significantly increasing overall manufacturing complexity.
Solution Approach 2:
The patent applies local quality principles by giving different fin heights to different device regions based on their specific performance requirements. This allows each local area to have optimized driving capabilities while the overall manufacturing process remains relatively simple and standardized.
Data Source
AI summary
The present disclosure provides a semiconductor device and a method for manufacturing the same. The semiconductor device comprises: a semiconductor layer; a first fin being formed by patterning the semiconductor layer; and a second fin being formed by patterning the semiconductor layer, wherein: top sides of the first and second fins have the same height; bottom sides of the first and second fins adjoin the semiconductor layer; and the second fin is higher than the first fin. According to the present disclosure, a plurality of semiconductor devices with different dimensions can be integrated on the same wafer. As a result, manufacturing process can be shortened and manufacturing cost can be reduced. Furthermore, devices with different driving capabilities can be provided.