Selective Fin Liner for Precise Semiconductor Fin Removal
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Solution Overview
Problem
Existing fin removal methods in semiconductor fabrication, such as the 'fin cut first' and 'fin cut last' processes, often result in edge fins being wider than center fins, leading to performance issues and damage to adjacent fins during the removal process due to misalignment.
Innovation Solution
Applying a selective fin liner to protect fins that are to be kept, allowing for the removal of unwanted fins without damaging adjacent ones, using materials like enhanced high aspect ratio process (eHARP) oxide or organic gap fill materials to facilitate precise etching and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the 'fin cut first' process is used to remove fins, then fin removal is achieved, but edge fins become wider than center fins causing performance degradation
Solution Approach 1:
A liner is deposited on the fins before the fin removal process. This preliminary action protects the fins during removal and prevents edge effects that cause non-uniform fin dimensions. The liner is applied in advance to all fins, ensuring they maintain consistent dimensions throughout the removal process.
Solution Approach 2:
The liner acts as an intermediary layer between the etch process and the fins. It mediates the interaction by being selectively removed only from fins that need to be removed, while protecting adjacent fins from damage. This intermediary layer ensures precise control over which fins are removed without affecting neighboring structures.
2Manufacturing precision
If the 'fin cut last' process is used to remove fins, then fin dimension control is improved, but adjacent fins are damaged due to misalignment
Solution Approach 1:
The liner serves as a protective intermediary that is selectively removed from target fins while remaining on adjacent fins. This selective removal mechanism allows precise control over which fins are removed without causing damage to neighboring structures, even when alignment variations occur during the removal process.
Solution Approach 2:
The liner provides localized protection to specific fins based on their position and function. By selectively removing the liner from certain fins while maintaining it on others, the process achieves local differentiation - protecting fins that need to remain while allowing removal of fins that should be eliminated, preventing cross-contamination of effects.
3Device complexity
If no fin liner is used during fin removal, then the process is simpler, but product yield decreases due to unwanted fin damage
Solution Approach 1:
The liner acts as a temporary intermediary protective layer that is added to the process. While it increases process steps, it dramatically improves reliability by preventing unwanted fin damage. The liner is selectively removed and used as a mask during etching, ensuring that only intended fins are removed while adjacent fins remain protected, thereby maintaining high product yield.
Solution Approach 2:
The liner is deposited in advance as a preliminary protective measure before the fin removal process. This preliminary action, though adding a process step, prevents damage to fins that would otherwise occur during removal, ensuring high product yield and reliability without significantly complicating the overall device structure.
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 method improves product yield by preventing unwanted fin damage during the removal process, ensuring consistent fin dimensions and enhancing device performance by protecting adjacent fins from damage.
Implementation Method 1
The fin liner is of a material that is selective compared to the semiconductor fins. Hence, the fins can be removed without significant damage to the fin liner.
Implementation Method 2
multiple fins may be merged together, usually with an epitaxially grown semiconductor, to provide greater drive current capability for certain transistors
Data Source
AI summary
Methods for removal of fins from a semiconductor structure are provided. A fin liner is applied to the fins. The fin liner is then removed from the fins that are to be removed. The fin liner is of a material that is selective compared to the semiconductor fins. Hence, the fins can be removed without significant damage to the fin liner. The subsets of fins that are to be removed are then removed, while the fin liner protects the adjacent fins that are to be kept.