Border Dam and Dummy Gate Layout for Scaled MOSFET Reliability
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Solution Overview
Problem
The scaling down of metal-oxide-semiconductor field-effect transistors (MOSFETs) in semiconductor devices leads to deterioration in operational properties, necessitating improvements in electric and reliability characteristics to meet the demand for smaller pattern sizes and reduced design rules.
Innovation Solution
A semiconductor device design featuring a substrate with a cell region, dummy region, and border region, including device isolation layers, gate electrodes, active and dummy contacts, and an interlayer insulating layer with a dam structure, which enhances electric and reliability characteristics by optimizing channel and source/drain patterns and gate configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If MOSFETs are scaled down to meet demand for smaller pattern sizes and reduced design rules, then the pattern size and design rule are reduced, but the operational properties of the semiconductor device deteriorate
Solution Approach 1:
The channel pattern is divided into multiple stacked semiconductor patterns (first, second, third semiconductor patterns) forming a multi-layer channel structure. This segmentation allows the device to maintain larger effective channel dimensions for improved operational properties while achieving smaller footprint through vertical stacking, thus resolving the contradiction between scale-down and operational performance.
Solution Approach 2:
The invention transitions from a planar channel structure to a three-dimensional stacked channel structure. By adding the vertical dimension with multiple stacked semiconductor patterns, the device achieves both compact lateral dimensions (meeting scale-down requirements) and sufficient vertical channel length (maintaining operational properties), effectively resolving the technical contradiction.
2Manufacturing precision
If MOSFETs are scaled down, then the design rule is reduced, but the operational properties and reliability of the semiconductor device deteriorate
Solution Approach 1:
The channel is segmented into multiple discrete semiconductor patterns stacked vertically, each pattern being manufacturable within existing design rules. The stacked configuration achieves the required effective channel length for reliability while keeping individual pattern dimensions within manufacturable limits, thus resolving the contradiction between design rule constraints and operational reliability.
Solution Approach 2:
By moving the channel length requirement to the vertical dimension through stacking, the lateral design rules remain manageable for fabrication while the cumulative vertical channel length provides the necessary operational properties. This dimensional transition resolves the conflict between manufacturability and device performance.
3Reliability
If the channel pattern uses stacked semiconductor patterns, then the electric characteristics are improved, but the device complexity increases
Solution Approach 1:
Multiple semiconductor patterns are merged into a single integrated channel structure through vertical stacking and lateral connection. This combining approach achieves improved electric characteristics through the multi-layer channel while presenting a unified structure that simplifies the overall device architecture and reduces the complexity of individual components.
Solution Approach 2:
The stacked semiconductor pattern structure serves multiple functions simultaneously: it provides the channel region for transistor operation, acts as the active pattern definition, and creates vertical spacing for gate electrode placement. This multi-functionality reduces the need for separate structural elements, thereby improving electric characteristics without proportionally increasing device complexity.
4Reliability
If the gate electrode crosses the channel patterns in a second direction intersecting the first direction, then the control over channel is improved, but the device complexity increases
Solution Approach 1:
The gate electrode configuration utilizes a second direction intersecting the first direction to create a cross-shaped or mesh-like gate structure. This adds dimensional control authority over the stacked channel patterns, improving gate control and electrical characteristics. The intersecting direction approach provides comprehensive channel coverage while maintaining a systematic structure that manages complexity through geometric regularity.
Data Source
AI summary
In some embodiments, the semiconductor device includes a substrate comprising a cell region, a dummy region spaced apart from the cell region in a first direction, and a border region between the cell region and the dummy region, an active pattern on the cell region, a device isolation layer on the substrate, source/drain patterns on the active pattern and channel patterns between the source/drain patterns, cell gate electrodes crossing the channel patterns in a second direction, active contacts disposed on the cell region and between the cell gate electrodes and coupled to the source/drain patterns, dummy gate electrodes on the dummy region and on the device isolation layer, dummy contacts on the dummy region and on a side surface of each of the dummy gate electrodes, an interlayer insulating layer on the side surface of each of the dummy gate electrodes, and a dam structure on the border region.