ESD Protection Circuit Layout With Overlapping Pad and Drain
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Solution Overview
Problem
Existing electrostatic protection circuits occupy a large chip area due to the size of discharge transistors and components like resistors and capacitors, which affects their effectiveness and efficiency in electrostatic discharge.
Innovation Solution
The electrostatic protection device includes a discharge transistor with a first pad on a metal layer partially overlapping its drain region, reducing the effective chip area and improving discharge speed and capability by minimizing parasitic resistance and capacitance through optimized metal layer connections and contact hole arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a discharge transistor with relatively large size is used to improve electrostatic discharge capability, then the electrostatic discharge capability is improved, but the chip area occupied increases
Solution Approach 1:
The first pad is positioned on a metal layer above the substrate, utilizing the vertical dimension to overlap with the drain region projection. This three-dimensional arrangement allows electrical connection without increasing the horizontal chip area, resolving the contradiction between discharge capability and area occupation.
Solution Approach 2:
The first pad structure is nested within the vertical space above the drain region, with the pad's projection overlapping the drain region's projection on the substrate. This nesting approach allows the pad to be contained within the same horizontal footprint as the transistor, reducing overall chip area while maintaining discharge capability.
2Stability of the object's composition
If resistors and capacitors are added to improve pulse characteristics, then the pulse characteristics are improved, but the chip area occupied increases
Solution Approach 1:
The metal layer structure integrates multiple functions into a unified configuration, combining the pad connection function with the discharge path function. This merging eliminates the need for separate resistor and capacitor components, achieving pulse characteristic improvement without additional area occupation.
Solution Approach 2:
The first pad and metal layer structure serves multiple functions simultaneously: providing electrical connection, establishing discharge paths, and influencing pulse characteristics. This multi-functionality reduces the need for dedicated separate components, thereby reducing overall chip area while maintaining performance.
3Area of stationary object
If the first pad is positioned to overlap the drain region, then the chip area is reduced, but parasitic resistance and capacitance may increase
Solution Approach 1:
The metal layer and pad are strategically positioned to create optimal local electrical pathways. By carefully designing the overlap configuration and metal layer connectivity, the solution minimizes parasitic resistance and capacitance in critical regions while maintaining compact overall area, addressing the local quality of electrical properties rather than uniform distribution.
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 configuration reduces the effective chip area, enhances electrostatic discharge speed and capability, and reserves space for other components, while minimizing heat generation and improving reliability.
Implementation Method 1
a discharge transistor, located on a substrate and configured to discharge electrostatic charges
Data Source
AI summary
The present disclosure provides an electrostatic protection device and an electrostatic protection circuit. The electrostatic protection device includes: a discharge transistor, located on a substrate for discharging electrostatic charges; and a first pad, located on a first metal layer and electrically connected to a drain region of the discharge transistor; wherein a projection of the first pad on the substrate partially overlaps a projection of the drain region on the substrate.