FinFET Devices with Variable Fin Heights via Liner Etching
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Solution Overview
Problem
Conventional FinFET devices have fixed fin heights, limiting flexibility in designing integrated circuits with varying drive current requirements, as the channel width is determined by the fin height, making it difficult to produce FinFETs with fractional drive current strengths and affecting device performance and manufacturing complexity.
Innovation Solution
A method involving multiple etching processes to form FinFET devices with different fin heights by varying the thickness of liner materials and insulating layers, allowing for distinct fin heights and channel widths, enabling the production of FinFETs with adjustable drive currents while maintaining uniform physical size, thus enhancing design flexibility and manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional FinFET devices with fixed fin heights are used, then manufacturing process is simpler, but design flexibility is limited and cannot produce fractional drive current strengths
Solution Approach 1:
The manufacturing process is segmented into multiple distinct etching steps, where each etching step targets specific regions with different liner thicknesses to create fins of different heights. This segmentation allows independent control of fin heights in different device regions, enabling design flexibility while maintaining a systematic manufacturing approach.
Solution Approach 2:
Different liner material thicknesses are deposited in different regions of the substrate, creating local variations in fin height. This local quality approach allows specific areas to have customized fin heights tailored to their drive current requirements, while other areas maintain different heights, all within the same manufacturing batch.
2Adaptability or versatility
If multiple etching processes with varying liner thicknesses are used to form different fin heights, then design flexibility and adjustable drive currents are improved, but manufacturing complexity increases
Solution Approach 1:
The invention changes the parameter of liner material thickness to control fin height. By varying the liner thickness parameter across different regions before etching, the process achieves adjustable drive current strengths. This parameter-based control integrates multiple fin height configurations into a unified manufacturing flow.
Solution Approach 2:
Liner materials of different thicknesses are deposited in advance on the substrate before the etching process. This preliminary action establishes the fin height profile beforehand, so that subsequent etching steps simply follow the pre-defined liner structure, reducing the complexity of real-time process control.
3Power
If fin height is increased to increase channel width, then drive current capability is improved, but physical size of device increases
Solution Approach 1:
Instead of increasing drive current by expanding the device footprint in the planar dimension, the invention utilizes the vertical dimension by creating fins of different heights. This dimensional transition allows multiple drive current levels to be achieved within the same lateral footprint, effectively decoupling drive current from device area.
Data Source
AI summary
One illustrative method disclosed herein includes forming a plurality of trenches in a plurality of active regions of a substrate that defines at least a first plurality of fins and a second plurality of fins for first and second FinFET devices, respectively, forming liner materials adjacent to the first and second plurality of fins, wherein the liner materials adjacent the first fins and the second fins have a different thickness. The method also includes removing insulating material to expose portions of the liner materials, performing an etching process to remove portions of the liner materials so as to expose at least one fin in the first plurality of fins to a first height and at least one of the second plurality of fins to a second height that is different from the first height.