FinFET Fabrication Insulator Protection for Fin Damage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
During the fabrication of FinFETs, the patterned photoresist layer used in the fin cut process may not be thick enough to protect semiconductor fins in dense areas, leading to fin damage and instability in the process.
Innovation Solution
The method involves forming insulators in trenches that partially cover the semiconductor fins, allowing a patterned photoresist layer to protect the fins during the fin cut process, and subsequently forming a gate dielectric layer to fill the concaves created between the insulators, ensuring proper protection and structure integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a patterned photoresist layer is used to protect semiconductor fins during the fin cut process, then the fins can be partially protected, but the photoresist layer is not thick enough to provide sufficient protection, especially in dense areas
Solution Approach 1:
A protective layer is formed over the substrate before the fin cut process to provide preliminary protection to the semiconductor fins. This protective layer is applied in advance to ensure that the fins are adequately protected during the subsequent etching process, particularly in dense areas where protection is most critical.
Solution Approach 2:
The solution combines multiple protective elements: a protective layer (which may be a different material than the photoresist alone) is used in conjunction with the patterned photoresist layer. This composite protective structure provides both the patterning function of the photoresist and the enhanced protection of the protective layer, ensuring sufficient thickness and protection capability.
2Reliability
If the photoresist layer is made thicker to provide better protection, then fin protection improves, but the process complexity and fabrication difficulty increase
Solution Approach 1:
The protective layer is formed as a preliminary step before the fin cut process, establishing the protection structure in advance. This allows for a systematic, step-by-step fabrication process that is easier to control and monitor, reducing overall process complexity despite the added protection layer.
Solution Approach 2:
The protection function is segmented into multiple components: the protective layer and the patterned photoresist layer. This segmentation allows each layer to be optimized independently for its specific function, simplifying the overall process design and making the complex protection requirement more manageable through divided functionality.
3Ease of manufacture
If the photoresist layer is made thinner to simplify the process, then fabrication ease improves, but fin damage increases due to insufficient protection
Solution Approach 1:
The protective layer is combined with the patterned photoresist layer to create a composite protective structure. This allows the photoresist layer to remain thin and easy to fabricate while the protective layer provides the additional thickness and protection needed, particularly in dense fin areas. The composite structure achieves both ease of manufacture and sufficient protection.
Solution Approach 2:
The protective layer is applied in advance to provide a foundation of protection before the photoresist patterning step. This preliminary protection ensures that even if the photoresist layer is thin, the underlying fins are still protected during the etching process, maintaining manufacturing precision without requiring thick photoresist layers.
Data Source
AI summary
A method for fabricating a fin field effect transistor (FinFET) comprising the following steps is provided. A substrate comprising a plurality of trenches and a plurality of semiconductor fins between the trenches is provided. A plurality of insulators are formed in the trenches. A fin cut process is performed to remove portions of the semiconductor fins until a plurality of concaves are formed between the insulators. A gate stack is formed to partially cover the semiconductor fins and the insulators.