FinFET Wicking Structure Control via Two-Step Cleaning
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Solution Overview
Problem
The current methods for forming finFETs face challenges in controlling fin height and pitch, leading to limitations in current density and performance as semiconductor devices continue to miniaturize.
Innovation Solution
A semiconductor device with two fin-shaped structures and an insulating layer is developed, where the insulating layer has a curved surface with a wicking structure between the fins, and a two-stepped cleaning process is used to minimize the wicking structure's coverage on the sidewalls, allowing precise control of fin height and improved current density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the insulating layer is recessed between fin shaped structures, then the fin height can be controlled, but a wicking structure is formed on the sidewalls of the fins which increases coverage and reduces current density
Solution Approach 1:
The patent applies the extraction principle by performing a two-stepped cleaning process that selectively removes the wicking structure formed on the sidewalls of the fin shaped structures. The first cleaning step uses a first etchant to remove the wicking structure, and the second cleaning step uses a second etchant to further clean the sidewalls. This extracts the harmful wicking structure while preserving the fin height control achieved through the recessed insulating layer.
Solution Approach 2:
The patent applies the discarding principle by intentionally allowing the wicking structure to form during the recessing process, then systematically removing it through the two-stepped cleaning process. The wicking structure is discarded as a byproduct of the recessing operation, and the cleaning steps recover the sidewall surface area that was otherwise lost to wicking structure coverage.
2Length of moving object
If continuous miniaturization is pursued, then device size is reduced, but the width of each fin and pitch between fins must be shrunk which creates fabricating challenges
Solution Approach 1:
The patent applies the self-service principle by using the recessing process itself to define the fin height through the formation of the insulating layer profile. The recessed insulating layer automatically creates the desired fin height when exposed, eliminating the need for additional height-defining steps. This self-defining mechanism enables miniaturization while maintaining manufacturing feasibility through a integrated process approach.
3Productivity
If the wicking structure coverage on sidewalls is increased, then the recessing process is more effective, but the current density of the semiconductor device is reduced
Solution Approach 1:
The patent applies the blessing in disguise principle by converting the harmful wicking structure into a beneficial process indicator. The wicking structure formation during recessing is not viewed as a defect to be avoided, but as an expected byproduct that signals effective recessing. The two-stepped cleaning process then converts this apparent harm into benefit by systematically removing the wicking structure, ensuring both effective recessing and preserved current density.
Data Source
AI summary
A semiconductor device and a method of forming the same, the semiconductor device includes fin shaped structures and a recessed insulating layer. The fin shaped structures are disposed on a substrate. The recessed insulating layer covers a bottom portion of each of the fin shaped structures to expose a top portion of each of the fin shaped structures. The recessed insulating layer has a curve surface and a wicking structure is defined between a peak and a bottom of the curve surface. The wicking structure is disposed between the fin shaped structures and has a height being about 1/12 to 1/10 of a height of the top portion of the fin shaped structures.