3D Semiconductor Isolation Structure for Fine-Pattern Reliability
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Solution Overview
Problem
The challenge of integrating semiconductor devices with fine patterns and addressing limitations in operating properties due to reduced size, particularly in planar metal oxide semiconductor FETs, has necessitated the development of transistors with three-dimensional structures.
Innovation Solution
A semiconductor device design featuring active regions with channel layers surrounded by gate structures, source/drain regions, and isolation structures, along with dummy active structures and isolation layers, enhances reliability and manufacturing stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If planar metal oxide semiconductor FETs are reduced in size to achieve high integration density, then integration density is improved, but operating properties deteriorate
Solution Approach 1:
The patent transitions from planar two-dimensional channel structures to three-dimensional vertical channel structures. The channel extends vertically through the substrate with the gate wrapping around it, creating a nanowire or nanosheet configuration that provides superior electrostatic control while maintaining high integration density through vertical stacking.
Solution Approach 2:
The gate structure is configured to surround and wrap around the vertical channel, creating a gate-all-around or partial gate-all-around structure. This nested configuration provides comprehensive electrostatic control of the channel from all directions, significantly improving device performance and reliability at scaled dimensions.
2Productivity
If fine patterns are implemented to achieve high integration density, then integration density is improved, but manufacturing precision requirements increase
Solution Approach 1:
By moving to vertical three-dimensional structures, the patent reduces the lateral footprint of each device while maintaining functional performance. This vertical scaling allows higher integration density without requiring proportionally tighter lateral patterning constraints, as the channel length and width can be controlled through vertical epitaxial growth rather than lateral lithography.
Solution Approach 2:
The patent changes the critical dimensions from lateral planar measurements to vertical thickness and height measurements. The channel is defined by vertical epitaxial growth parameters (temperature, pressure, gas flow, precursor ratios) rather than lateral photolithography parameters (wavelength, numerical aperture, resist chemistry), offering different process control mechanisms that can achieve fine dimensions with relaxed lateral patterning requirements.
3Reliability
If three-dimensional channel structures are introduced to overcome size limitations, then device performance is improved, but device complexity increases
Solution Approach 1:
The vertical channel structure with gate-all-around configuration provides superior electrostatic control and carrier transport properties compared to planar devices. The three-dimensional geometry enables better field effect control, higher on-current density, and improved threshold voltage modulation, directly enhancing operating properties despite the increased structural complexity.
Data Source
AI summary
A semiconductor device includes a substrate including a key region; dummy active structures on the key region, extending in a first direction parallel to an upper surface of the substrate, spaced apart from each other in a second direction perpendicular to the first direction, and each including at least one dummy active region; a dummy device isolation layer in the key region and defining the at least one dummy active region; and a dummy upper isolation structure on the dummy device isolation layer and a portion of each of the dummy active structures and including first patterns extending in the first direction.