Fin Transistor Gate Line and Spacer Structure for Integration Density
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Solution Overview
Problem
Conventional processes for manufacturing fin transistors face challenges in forming gate electrodes and contacts, particularly with decreasing device feature sizes, leading to difficulties in achieving high-quality gate patterns and precise electrical isolation, which affects integration density and manufacturing costs.
Innovation Solution
A method involving the formation of gate lines intersecting fins via a gate dielectric layer, followed by the creation of dielectric and conductive spacers on the outer sides of the gate lines, with subsequent inter-device electrical isolation, allowing for self-aligned contacts and reduced spacer material between devices, eliminating voids and improving integration density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional processes are used to form gate electrodes and contacts in fin transistors, then the manufacturing process is straightforward, but manufacturing precision deteriorates as device feature sizes become smaller
Solution Approach 1:
The gate electrode formation is segmented into multiple steps: first forming a gate line, then using dielectric spacers to define gate electrode regions, and finally forming conductive spacers for contacts. This segmentation allows precise control of gate patterns even at small feature sizes by separating the formation of different structural elements.
Solution Approach 2:
Dielectric spacers are formed preliminarily around the gate line before forming the conductive spacers and contacts. This preliminary action establishes precise spatial boundaries that guide subsequent contact formation, ensuring high manufacturing precision without requiring direct alignment at each step.
2Ease of manufacture
If conventional contact formation processes are used, then contacts are formed by etching contact holes and filling metal, but this becomes increasingly difficult with smaller feature sizes
Solution Approach 1:
Conductive spacers are formed to surround dielectric spacers, and the dielectric spacers themselves serve as alignment references. The structure is self-aligning: the conductive spacer automatically positions itself relative to the gate electrode through the dielectric spacer intermediary, eliminating the need for separate alignment operations and making the process easier at small dimensions.
Solution Approach 2:
Dielectric spacers act as intermediary structures between the gate line and the conductive contacts. They provide a physical reference that mediates the positioning of conductive spacers, simplifying the manufacturing process by removing the need for precise direct alignment between gate electrodes and contacts.
3Reliability
If more spacer material is left between devices, then electrical isolation is improved, but integration density decreases
Solution Approach 1:
Electrical isolation is achieved not only through lateral spacing but also through vertical layering with dielectric spacers and conductive spacers formed in different dimensions. This multi-dimensional approach allows reduced lateral isolation space while maintaining reliable electrical isolation through the spacer structures.
Solution Approach 2:
Dielectric spacers are formed selectively at specific locations (around gate lines and at device boundaries) rather than uniformly across all device regions. This localized formation of isolation structures provides sufficient electrical isolation where needed while minimizing the impact on overall integration density.
Data Source
AI summary
A semiconductor device structure and a method for manufacturing the same are disclosed. In one embodiment, the method comprises: forming a fin in a first direction on a semiconductor substrate; forming a gate line in a second direction crossing the first direction on the semiconductor substrate, the gate line intersecting the fin via a gate dielectric layer; forming a dielectric spacer surrounding the gate line; forming a conductive spacer surrounding the dielectric spacer; and performing inter-device electrical isolation at a predetermined region, wherein isolated portions of the gate line form gate electrodes of respective unit devices, and isolated portions of the conductive spacer form contacts of the respective unit devices.