FinFET Epitaxial Integrity via Hardmask Protection
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Solution Overview
Problem
In the manufacturing of fin-type field effect transistors (FinFETs), the removal of the dummy gate structure during the epitaxial process can cause damage to the semiconductor fin and source/drain regions due to etching, leading to incomplete epitaxial morphology and decreased device performance.
Innovation Solution
A method involving a substrate structure with a trench isolation structure and a patterned hardmask layer is used to expose and protect the semiconductor fin, allowing for controlled etching and removal of the dummy gate without damaging the fin, thereby maintaining the integrity of the epitaxial regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the dummy gate structure is removed using etching during the epitaxial process, then the epitaxial growth can proceed, but the semiconductor fin and source/drain regions are damaged by the etching solution
Solution Approach 1:
The patent introduces an intermediary protective structure consisting of a first hardmask layer and first insulator layer that mediates between the etching solution and the semiconductor fin/source/drain regions. This protective layer allows the dummy gate removal to proceed while preventing direct contact between the etching solution and the sensitive semiconductor structures, thus eliminating the harmful etching effect while maintaining the beneficial epitaxial growth process
2Reliability
If the dummy gate structure is protected during removal, then the semiconductor fin integrity is maintained, but the process complexity increases with additional protective layers
Solution Approach 1:
The patent applies preliminary action by forming the protective hardmask layer and insulator layer before the dummy gate removal process. These protective structures are prepared in advance and integrated into the existing process flow, allowing the fin integrity to be maintained without requiring complex real-time adjustments during the removal process itself
Data Source
AI summary
A method for manufacturing a semiconductor device includes providing a substrate structure including a semiconductor fin on a substrate, and a trench isolation structure surrounding the fin and having an upper surface flush with an upper surface of the fin and including first and second trench isolation portions on opposite sides of the fin along the fin longitudinal direction, and third and fourth trench isolation portions on distal ends of the fin along a second direction intersecting the longitudinal direction; forming a patterned first hardmask layer having an opening exposing an upper surface of the third and fourth trench isolation portions; and forming a first insulator layer filling the opening to form an insulating portion including a portion of the first insulator layer in the opening and a portion of the trench isolation structure below the portion of the first insulator layer in the opening.