Fin-Shaped Structure Forming Process for Multi-Gate MOSFETs
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Solution Overview
Problem
The miniaturization of semiconductor devices requires the fabrication of fin-shaped structures with varying widths for multi-gate MOSFETs, which existing processes struggle to achieve effectively, impacting the control of the channel region and current between the source and drain.
Innovation Solution
A fin-shaped structure forming process that involves forming mandrels on a substrate, covering them with spacer materials of different thicknesses, etching to create spacers, and transferring the spacer layout to form fin-shaped structures with distinct widths, utilizing techniques like photoresist etching to achieve the desired dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing fin-shaped structure formation processes are used, then the fabrication process is simple, but fin-shaped structures with varying widths cannot be achieved
Solution Approach 1:
The fabrication process is segmented into multiple stages: forming different mandrels (first and second mandrels), depositing different spacer materials (first and second spacer materials) with varying thicknesses, selective etching to create spacers of different widths, and sequential pattern transfers. This segmentation enables precise control over fin-shaped structure widths while maintaining process manageability through modular fabrication steps.
2Reliability
If multi-gate MOSFET devices are fabricated with varying fin widths, then the channel region control and current increase, but the fabrication process complexity increases
Solution Approach 1:
Different regions of the substrate receive different treatments to create local variations in fin-shaped structure widths. First mandrels and second mandrels are formed with different dimensions, covered by spacer materials of different thicknesses, and subjected to selective etching. This local quality approach enables optimized channel region control and current characteristics in different device regions while maintaining overall process integration.
3Manufacturing precision
If spacer materials of different thicknesses are used, then fin-shaped structures with different widths are formed, but the process steps increase
Solution Approach 1:
Spacer materials of different thicknesses are deposited in advance on different mandrels before the final pattern transfer. The first spacer material is deposited to a first thickness on the first mandrel, and the second spacer material is deposited to a second thickness on the second mandrel. This preliminary action enables precise width control in the final fin-shaped structures while consolidating multiple deposition steps into an integrated process sequence.
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 process enables the formation of fin-shaped structures with different widths, enhancing the control of the channel region and increasing the current between the source and drain, thereby improving the performance of multi-gate MOSFETs.
Implementation Method 1
The exposed first spacer material is etched to form a first spacer on the substrate beside the first mandrel
Data Source
AI summary
A fin-shaped structure forming process includes the following step. A first mandrel and a second mandrel are formed on a substrate. A first spacer material is formed to entirely cover the first mandrel, the second mandrel and the substrate. The exposed first spacer material is etched to form a first spacer on the substrate beside the first mandrel. A second spacer material is formed to entirely cover the first mandrel, the second mandrel and the substrate. The second spacer material and the first spacer material are etched to form a second spacer on the substrate beside the second mandrel and a third spacer including the first spacer on the substrate beside the first mandrel. The layout of the second spacer and the third spacer is transferred to the substrate, so a second fin-shaped structure and a first fin-shaped structure having different widths are formed respectively.