Distributed Contact Plug for Ultra-High Voltage ESD Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ultra-high voltage devices face challenges in electro-static discharge (ESD) protection due to non-uniform current distribution, leading to localized heat concentration and potential damage, as existing ESD protection schemes are not applicable to these large devices and cannot meet minimum ESD requirements.
Innovation Solution
A distributed contact plug structure and multiple fuse apparatus with poly fuses are integrated into the high voltage path to ensure uniform current distribution and prevent overheating, using a poly fuse that breaks down under excessive current, redirecting the current to other fuses and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional ultra-high voltage device structure is used, then the device can support high voltage operation, but the current distribution is non-uniform leading to localized heat concentration and potential device damage
Solution Approach 1:
The contact plug is divided into multiple discrete contact regions (first contact region, second contact region, third contact region) distributed across the high voltage N-well. This segmentation distributes the current flow paths, preventing concentration at a single point and reducing localized heat generation during ESD events.
Solution Approach 2:
Different regions of the high voltage N-well are given different functions: the first contact region connects to the high voltage electrode, the second contact region forms a PN junction with the P-substrate for ESD protection, and the third contact region provides additional current distribution. This local differentiation optimizes both high voltage operation and ESD protection in specific areas.
2Reliability
If ESD protection schemes are added to ultra-high voltage devices, then ESD protection capability improves, but the device dimensions increase which is not acceptable for already huge dimension devices
Solution Approach 1:
The high voltage N-well serves multiple functions simultaneously: it provides the high voltage potential well for operation, contains the distributed contact regions for current distribution, and forms PN junctions with the P-substrate for ESD protection. This multi-functionality integrates ESD protection into the existing high voltage structure without adding separate protection circuits that would increase device area.
Solution Approach 2:
The ESD protection function is merged with the high voltage device structure by forming PN junctions between the P-substrate and specific contact regions of the high voltage N-well. This combination eliminates the need for separate ESD protection structures, maintaining compact device dimensions while providing robust ESD protection.
3Ease of manufacture
If the contact plug has a concentrated structure, then the manufacturing is simpler, but the current distribution becomes non-uniform causing localized damage
Solution Approach 1:
The contact plug is segmented into multiple discrete contact regions formed through separate doping processes (first doping process for first contact region, second doping process for second contact region, third doping process for third contact region). While this requires multiple processing steps, each region can be precisely controlled to ensure uniform current distribution, achieving both manufacturability and current uniformity.
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
This solution effectively enhances ESD protection for ultra-high voltage devices by distributing current uniformly, reducing the risk of damage and maintaining device functionality even under excessive current conditions without increasing device dimensions or manufacturing complexity.
Implementation Method 1
When there is a great current, such as an ESD current, flowing through the high voltage path, the current intends to concentrate around the terminal 32 and produce great heat, resulting in localized high temperature to melt down this portion of the ultra-high voltage device
Data Source
AI summary
An ultra-high voltage device has a high voltage path established from a high voltage N-well through a first metal layer to a second metal layer, and a contact plug electrically connected between the high voltage N-well and the first metal layer. The contact plug has a distributed structure on a horizontal layout to improve the uniformity of the ultra-high voltage device such that the current in the high voltage path will be more uniform distributed so as to avoid the localized heat concentration caused by non-uniform current distribution that would damage the ultra-high voltage device. Multiple fuse apparatus are preferably connected to the first metal layer individually. Each the fuse apparatus includes a poly fuse to be burnt down when an over-load current flows therethrough.