Fin Structure Oxidation Control for Uniform Fin Widths
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Solution Overview
Problem
The pattern loading effect in FinFETs results in significant variations in fin widths, leading to performance inconsistencies due to non-uniform etching rates across different regions of the substrate.
Innovation Solution
A protecting layer is selectively formed on specific fin structures to control oxidation rates and offset the pattern loading effect, ensuring uniform fin width reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching is used to form fin structures, then fin structures are formed, but significant variations in fin widths occur due to pattern loading effect
Solution Approach 1:
The patent applies different oxidation conditions to different regions of the substrate. Specifically, fins in the first region (higher density area) are oxidized at a first oxidation rate, while fins in the second region (lower density area) are oxidized at a second oxidation rate. This local differentiation compensates for the pattern loading effect and achieves uniform fin widths across the substrate.
Solution Approach 2:
The patent changes the oxidation rate parameter based on spatial location. By adjusting the oxidation rate from a first rate in the first region to a second rate in the second region, the patent compensates for etching rate variations caused by pattern loading, thereby achieving uniform fin widths.
2Stability of the object's composition
If uniform oxidation is applied across the substrate, then oxidation proceeds uniformly, but fin width variations are not compensated for pattern loading effect
Solution Approach 1:
The patent implements spatially varying oxidation rates by applying different oxidation conditions to different regions. The first region receives oxidation at a first rate while the second region receives oxidation at a second rate, creating local quality differences that compensate for pattern loading effects.
Solution Approach 2:
The patent applies preliminary compensation through differential oxidation before final fin formation is complete. By anticipating the pattern loading effect and applying counteracting oxidation rate variations in advance, the patent prevents fin width variations from occurring.
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
The method reduces fin width variations and enhances the performance consistency of FinFETs by predictably managing oxidation rates across the substrate.
Implementation Method 1
A protecting layer is selectively formed on specific fin structures to control oxidation rates and offset the pattern loading effect
Data Source
AI summary
A method includes: receiving a substrate including a first region and a second region; patterning the substrate to form a first fin structure and a pair of second fin structures, wherein the first fin structure is between the second fin structures; forming a protecting layer on each of the pair of second fin structures while exposing a lateral surface of the first fin structure; forming a first oxide layer over the first fin structure and forming a second oxide layer over the protecting layer; depositing an isolation region to laterally surround the first oxide layer and the second oxide layer; and performing a recessing operation to remove an upper portion of the isolation region, the recessing operation further removing an upper portion of the first oxide layer from the first fin structure and an upper portion of the second oxide layer from the pair of the second fin structures.