ESD Protection Structure With Segmented Doped Regions
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Solution Overview
Problem
As semiconductor manufacturing advances to the deep sub-micron stage, integrated circuits (IC) become increasingly vulnerable to electrostatic discharge (ESD) stress, requiring effective ESD protection for input/output pads to withstand high voltage levels without damage.
Innovation Solution
An ESD protection structure comprising a substrate with specific doped regions and isolation regions, where the doped regions are coupled to power lines to divert ESD current away from sensitive areas, ensuring that the ESD current path does not directly collide with isolation regions, thereby enhancing the holding voltage and protecting the IC from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ESD protection devices are added to input/output pads to withstand high voltage levels, then the reliability of IC against ESD stress is improved, but the device complexity increases
Solution Approach 1:
The ESD protection structure is segmented into multiple doped regions (first, second, third, and fourth doped regions) with different conductive types, each serving specific functions in the ESD current path. This segmentation allows the structure to handle high voltage ESD stress while maintaining controlled complexity through functional division.
Solution Approach 2:
Different regions of the substrate are doped with different conductive types (first and second conductive types) to create local quality variations. The first diffusion region has different properties than the substrate, and isolation regions are strategically placed to control ESD current flow locally, protecting sensitive areas while maintaining overall reliability.
2Reliability
If doped regions are used to divert ESD current, then the holding voltage is increased, but the manufacturing precision requirements increase
Solution Approach 1:
The doped regions are pre-configured in the substrate during manufacturing with specific conductive types and positions. The first diffusion region, second doped region, third doped region, and fourth doped region are all preliminarily arranged to ensure proper ESD current diversion paths, reducing the need for post-manufacturing adjustments and simplifying the overall manufacturing process.
Solution Approach 2:
The first diffusion region acts as an intermediary between the substrate and the doped regions, facilitating controlled ESD current flow. The isolation regions serve as mediators to separate and control the interaction between different doped regions, ensuring that ESD current follows the intended path while protecting sensitive areas from direct collision.
3Reliability
If isolation regions are placed between doped regions to protect sensitive areas, then the ESD current path control is improved, but the area occupied by the protection structure increases
Solution Approach 1:
The isolation regions are implemented as thin film or shallow structures that separate doped regions without occupying significant vertical or lateral space. This allows effective ESD current path control while minimizing the area consumed by the protection structure, maintaining compact IC design.
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 proposed ESD protection structure effectively manages ESD stress by redirecting ESD current, thereby increasing the holding voltage and ensuring the reliability of ICs against electrostatic discharge, even at high voltage levels.
Implementation Method 1
an ESD current can be released to the second power line from the first power line. During the release of the ESD current
Implementation Method 2
The first diffusion region is formed in the substrate and comprises a second conductive type. The first doped region is formed in the first diffusion region and comprises the first conductive type.
Data Source
AI summary
An ESD protection structure is disclosed. A substrate comprises a first conductive type. A first diffusion region is formed in the substrate. A first doped region is formed in the first diffusion region. A second doped region is formed in the first diffusion region. A third doped region is formed in the substrate. A first isolation region is formed in the substrate, covers a portion of the first diffusion region and is located between the second and the third doped regions. A fourth doped region is formed in the substrate. When the first doped region is coupled to a first power line and the third and the fourth doped regions are coupled to a second power line, an ESD current can be released to the second power line from the first power line. During the release of the ESD current, the second doped region is not electrically connected to the first power line.