FinFET ESD Protection Device Thermal Dissipation Path
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Solution Overview
Problem
Fin-based field effect transistor (FET) technology faces increased manufacturing costs and area consumption due to inefficient thermal energy dissipation during electrostatic discharge (ESD) events, as there is no direct path for thermal energy dissipation in existing ESD devices.
Innovation Solution
A bulk fin-based ESD protection device is designed with a semiconductor substrate and an isolating layer, featuring recesses that create regions with reduced thickness, allowing for homogeneous doping of upper substrate portions to form a thermal dissipation path, which enables efficient heat removal during ESD events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fin-based FET technology is used for ESD protection, then device functionality is achieved, but area consumption increases and manufacturing cost increases due to inefficient thermal energy dissipation
Solution Approach 1:
The patent utilizes the vertical dimension by forming recesses in the isolating layer that expose upper substrate portions, creating a three-dimensional thermal dissipation path. This vertical integration allows heat to conduct from the fin through the reduced-thickness isolating layer regions directly to the substrate, effectively adding a thermal management dimension without increasing planar area consumption.
Solution Approach 2:
The patent applies local quality by creating regions with reduced isolating layer thickness only in specific areas where thermal dissipation is needed. The recesses are strategically positioned to expose upper substrate portions locally, allowing efficient heat conduction paths while maintaining the full isolating layer thickness in other areas for proper electrical isolation.
2Reliability
If fin-based FET technology is used for ESD protection, then device functionality is achieved, but manufacturing cost increases due to inefficient thermal energy dissipation
Solution Approach 1:
The patent merges the thermal dissipation function with the existing fin structure and isolating layer. By forming recesses in the isolating layer and doping the exposed upper substrate portions, the invention combines electrical isolation, thermal management, and ESD protection functions into a single integrated structure, eliminating the need for separate thermal management components and reducing overall manufacturing complexity.
Solution Approach 2:
The upper substrate portions exposed through recesses serve multiple functions: they provide thermal dissipation paths for heat generated during ESD events, maintain electrical isolation through proper doping, and structurally support the fin. This multi-functionality reduces the need for additional dedicated thermal management structures, simplifying the manufacturing process.
3Device complexity
If no direct thermal dissipation path is provided, then device structure is simpler, but thermal energy buildup reduces ESD device functionality
Solution Approach 1:
The patent introduces the upper substrate portions exposed through recesses as intermediary thermal conduction paths. These doped substrate regions act as thermal mediators between the fin (heat source) and the bulk substrate (heat sink), facilitating efficient heat transfer without requiring complex active cooling systems or additional thermal management components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a robust thermal dissipation path, reducing the risk of device damage from thermal energy buildup and minimizing manufacturing costs by integrating an additional step into standard HDD manufacturing processes, resulting in improved thermal durability and reduced area consumption.
Implementation Method 1
By doping the upper substrate portions, a thermal dissipation path is provided for heat generated in the fin.
Data Source
Figure 1a~1b
Figure 2a~2c
Figure 3~4
AI summary
Described herein is an electrostatic discharge (ESD) protection device implemented in finFET technology. The device has a reduced thickness shallow trench isolation (STI) layer (120') which allows migration of high-doped drain implants (240, 250) therethrough to form regions (290, 300) extending under the STI layer (120') thereby creating a planar-like region under the STI layer (120'). The regions (290, 300) are formed in an n-well layer (180) provided between a substrate (100) and the STI layer (120'). The formation of the planar-like region under the STI layer (120') has the advantage that part of the thermal energy produced in the device during an ESD event is generated under the STI layer where it can be more efficiently dissipated towards a substrate (100).