Semiconductor Fin Removal Using Angled Implantation Selectivity
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Solution Overview
Problem
Existing semiconductor fin structures lack efficient methods for selectively removing specific fins while maintaining the integrity and functionality of the remaining fins, which is crucial for optimizing fin-based devices like FinFETs.
Innovation Solution
A method involving angled ion implantation and selective conversion of a dielectric material liner to form a compound material portion, followed by etching to remove targeted semiconductor fins, while preserving the remaining fins, is employed. This process includes applying a photoresist layer asymmetrically and using angled ion implantation to convert and remove specific portions of the material liner, enabling selective fin removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional isotropic etching is used to remove semiconductor fins, then the etching process is simple and fast, but it cannot selectively remove specific fins while preserving adjacent fins
Solution Approach 1:
The etching process is segmented into multiple sequential steps: first forming a dielectric liner around all fins, then performing angled ion implantation to modify only the liner surrounding the target fin, and finally executing a selective etch that removes only the implanted region. This segmentation enables precise spatial control over which fins are removed.
Solution Approach 2:
The dielectric liner is transformed from a uniform protective layer into a locally differentiated structure through angled ion implantation. The implantation creates a compound material portion with distinct etching properties only in the region surrounding the target fin, while the liner around other fins remains unchanged. This local quality variation enables selective removal of specific fins.
2Manufacturing precision
If angled ion implantation is performed to enable selective fin removal, then manufacturing precision is improved, but the process time and complexity increase
Solution Approach 1:
The dielectric liner is formed as a preliminary protective layer around all fins before the selective removal process begins. This preliminary action creates a uniform baseline structure that can then be selectively modified through ion implantation, streamlining the overall process by eliminating the need for separate masking steps for each fin.
Solution Approach 2:
The angled ion implantation process changes the physical and chemical parameters of the dielectric liner material in the implanted region, transforming it into a compound material with different etching characteristics. This parameter change enables the subsequent etch process to distinguish between implanted and non-implanted regions, achieving selective fin removal.
3Ease of manufacture
If the dielectric material liner is completely removed to access semiconductor fins, then fin removal is simplified, but the structural integrity and protection of remaining fins is compromised
Solution Approach 1:
Only the specific portion of the dielectric liner surrounding the target fin is removed through the selective etch process, while the liner around other fins remains intact. This extraction approach provides just enough access to remove the desired fin while maintaining protective coverage over the remaining fins, balancing ease of manufacture with structural integrity.
Solution Approach 2:
The dielectric liner serves as an intermediary protective layer that facilitates the selective removal process. By partially removing the liner only where needed, it acts as a mediator that enables controlled access to the target fin while continuing to protect other fins, thus maintaining reliability during the manufacturing process.
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 allows for precise and efficient removal of selected semiconductor fins, enhancing the performance and efficiency of FinFET devices by optimizing the number of channel regions and maintaining the structural integrity of the remaining fins.
Implementation Method 1
An angled ion implantation is performed to convert a top portion of dielectric material liner into a compound material portion
Data Source
AI summary
An array of semiconductor fins is formed on a top surface of a substrate. A dielectric material liner is formed on the surfaces of the array of semiconductor fins. A photoresist layer is applied and patterned such that sidewalls of an opening in the photoresist layer are parallel to the lengthwise direction of the semiconductor fins, and are asymmetrically laterally offset from a lengthwise direction passing through the center of mass of a semiconductor fin to be subsequently removed. An angled ion implantation is performed to convert a top portion of dielectric material liner into a compound material portion. The compound material portion is removed selective to the remaining dielectric material liner, and the physically exposed semiconductor fin can be removed by an etch or converted into a dielectric material portion by a conversion process. The dielectric material liner can be removed after removal of the semiconductor fin.