Semiconductor Fin Structure Sidewall Image Transfer Isolation
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Solution Overview
Problem
As semiconductor devices miniaturize, effective isolation between devices becomes crucial to prevent junction current leakage, and existing isolation technologies like STI are challenged by the need for tighter integration and reduced isolation regions.
Innovation Solution
The integration of isolation structures and fin structures is achieved through a process involving sidewall image transfer (SIT) methods, where a sacrificial layer is formed, etched, and patterned to create isolation structures and spacers, which are then transferred into the substrate to form fin structures, allowing for precise control of isolation and device separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional STI isolation structures are used to prevent junction current leakage, then device isolation is improved, but integration density deteriorates due to larger isolation regions
Solution Approach 1:
The patent combines the formation of isolation structures and fin structures into a single integrated process using sidewall image transfer (SIT) methods. The sacrificial layer serves dual purposes: defining both the isolation regions and the fin structures, eliminating the need for separate process steps and reducing overall isolation region area while maintaining effective device isolation.
Solution Approach 2:
The sacrificial layer performs multiple functions simultaneously: it defines the isolation structure boundaries, serves as a template for fin structure formation through spacer deposition, and enables precise pattern transfer. This multi-functionality reduces the number of process steps and minimizes the area occupied by isolation regions while ensuring effective device separation.
2Area of stationary object
If isolation regions are reduced to enhance integration density, then device separation deteriorates leading to increased junction current leakage
Solution Approach 1:
The spacer structure acts as an intermediary element that precisely defines the fin structure locations and widths. By forming spacers on the sacrificial layer and using them as masks for etching, the method achieves accurate device separation with minimal isolation region area, preventing junction current leakage while maintaining high integration density.
Solution Approach 2:
The patent replaces traditional mechanical patterning methods with sidewall image transfer (SIT) methodology. This substitution enables more precise pattern definition and better control over fin structure dimensions, achieving effective device separation with reduced isolation regions and minimizing junction current leakage pathways.
3Adaptability or versatility
If separate processes are used for isolation structures and fin structures, then manufacturing flexibility is improved, but process complexity deteriorates
Solution Approach 1:
The patent merges the formation of isolation structures and fin structures into a single integrated SIT process. The sacrificial layer and spacer formation serve as common templates for both structure types, reducing the total number of process steps while maintaining the ability to independently control the dimensions and locations of both isolation and fin structures through material selection and etch parameter optimization.
Data Source
AI summary
A semiconductor process including the following step is provided. A sacrificial layer is formed in a substrate. The sacrificial layer and the substrate are etched to form a trench in the sacrificial layer and the substrate. A first isolation material fills the trench, thereby a first isolation structure being formed. The sacrificial layer is patterned to form a plurality of sacrificial patterns. A plurality of spacers are formed beside the sacrificial patterns respectively. The sacrificial patterns are removed. Layouts of the spacers are transferred into the substrate, so that a plurality of fin structures are formed in the substrate. The spacers are then removed. The present invention also provides a semiconductor structure formed by said semiconductor process.