Fin-Shaped Structure Taper Profile via Spacer Transfer
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Solution Overview
Problem
The miniaturization of semiconductor devices poses challenges in achieving standard requirements and overcoming physical limitations in the sizes and shapes of fin-shaped structures and spacings between them in multi-gate MOSFETs, affecting electrical and physical properties.
Innovation Solution
A method for forming a fin-shaped structure with a taper profile is developed, involving the formation of a pad layer, a sacrificial pattern, and spacers with a height ratio greater than 5, followed by transferring the spacer layout into the substrate to create fin-shaped structures with specific dimensions and profiles, such as a maximum width of 5-20 nanometers and a pitch of 70 nanometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of multi-gate MOSFETs is reduced to achieve miniaturization, then device density and integration are improved, but the electrical and physical requirements for fin-shaped structures become more critical and difficult to meet
Solution Approach 1:
The fin-shaped structure is segmented into multiple portions along the channel direction, with each portion having a different width. This segmentation allows the device to achieve miniaturization while maintaining proper electrical characteristics in each segment, resolving the contradiction between device density and manufacturing precision requirements.
Solution Approach 2:
Different regions of the fin-shaped structure are given different local qualities (widths) to optimize performance. The varying width along the channel direction allows specific regions to meet critical electrical requirements while the overall structure achieves the desired miniaturization and density.
2Productivity
If the fin-shaped structure width is reduced to increase device density, then more fins can be packed, but the control of electrical properties and overcoming physical limitations become more difficult
Solution Approach 1:
The fin-shaped structure implements local quality variations with different widths at different positions along the channel. This allows the structure to maintain adequate width in regions where electrical control is critical, while reducing width in other regions to increase overall device density, thus resolving the contradiction between density and reliability.
Solution Approach 2:
The fin-shaped structure transitions from a uniform static geometry to a dynamic, varying geometry along the channel direction. This dynamic width variation allows the structure to adapt to different electrical requirements at different positions, maintaining reliability while enabling higher density.
3Ease of manufacture
If uniform fin-shaped structures are used, then the manufacturing process is simpler, but the electrical performance and control over short channel effects are insufficient
Solution Approach 1:
The fin-shaped structure is divided into multiple segments with different widths along the channel direction. This segmentation can be achieved through sequential deposition and etching processes, maintaining reasonable manufacturing simplicity while dramatically improving short channel effect control through the varied geometry.
Solution Approach 2:
The fin-shaped structure transitions from a two-dimensional uniform cross-section to a three-dimensional structure with varying width along the channel direction. This dimensional complexity improves electrical performance and short channel control while the manufacturing process remains relatively straightforward using standard semiconductor fabrication techniques.
Data Source
AI summary
A method for forming a fin-shaped structure includes the following steps. A pad layer is formed on a substrate. A sacrificial pattern is formed on the pad layer. A spacer is formed on the pad layer beside the sacrificial pattern, wherein the ratio of the height of the spacer to the pad layer is larger than 5. The sacrificial pattern is removed. The layout of the spacer is transferred to the substrate to form at least a fin-shaped structure having a taper profile in the substrate.