Bidirectional ESD Diode Structure With Low-Capacitance Steering

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Solution Overview

Problem

Prior semiconductor devices for bidirectional electrostatic discharge (ESD) protection are inadequate due to high capacitance, increased package size, and manufacturing costs, with existing solutions being unsatisfactory in terms of ESD performance and reliability.

Innovation Solution

A semiconductor device structure utilizing a large area Zener diode at the back side of a substrate in series with a low capacitance steering diode at the top side, combined in parallel with another low capacitance steering diode and a sub-surface Zener diode, allowing for bi-directional ESD protection within a single die, minimizing die area and I/O requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two separate dies or two I/Os are used to make ESD protection devices bi-directional, then bidirectional protection is achieved, but device complexity and manufacturing costs increase

Engineering Contradiction:

Improvebidirectional protection capabilityVSAvoidnumber of dies and I/Os

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple ESD protection functions into a single semiconductor die by integrating a first ESD protection device with a second ESD protection device in series connection. This merging approach eliminates the need for separate dies and reduces I/O requirements while maintaining bidirectional protection capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single semiconductor die is designed to perform multiple ESD protection functions simultaneously - protecting against both positive and negative voltage transients through the series-connected ESD devices. This multi-functional design allows one die to replace what would traditionally require two separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If traditional bidirectional ESD protection configurations are used, then ESD protection is provided, but capacitance increases and performance decreases

Engineering Contradiction:

ImproveESD protection effectivenessVSAvoidcapacitance

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies different structural configurations to different parts of the ESD protection circuit - using specific junction arrangements and doping profiles in the first and second ESD protection devices to optimize their individual capacitance characteristics. This localized optimization allows the series combination to achieve low overall capacitance while maintaining effective ESD protection.

Inventive Principle:

Principle #3Local quality

3Reliability

If larger die area is used for bidirectional ESD protection, then ESD performance improves, but manufacturing costs and package size increase

Engineering Contradiction:

ImproveESD survival capabilityVSAvoidsemiconductor die area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent utilizes vertical series connection of ESD protection devices within the die structure, effectively using the third dimension (depth/stacking) rather than only horizontal expansion. This dimensional transition allows achieving enhanced ESD protection capability without proportionally increasing the die footprint area.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 provides improved ESD performance with reduced capacitance, smaller package size, and lower manufacturing costs, enhancing reliability and efficiency while allowing for adjustable breakdown voltages.

Implementation Method 1

A first Zener diode is in a series combination with the first P-N diode

Methodology Applied

Scientific EffectZener effect:

Implementation Method 2

A first semiconductor region of a second conductivity type opposite to the first conductivity type and having approximately the first peak dopant concentration, wherein the first semiconductor region forms a first P-N junction with the semiconductor substrate

Methodology Applied

Scientific EffectPN junction breakdown:

Data Source

PatentUS11948933B2Semiconductor devices and methods of manufacturing semiconductor devices

Publication Date: 2024.04.02 SEMICON COMPONENTS IND LLC

AI summary

In an example, a semiconductor device includes a first steering diode and a second steering diode at a top side of a region of semiconductor material, a first Zener diode buried within the region of semiconductor material, and a second Zener diode at a bottom side of the region of semiconductor material. The semiconductor device is configured as a bi-directional electrostatic discharge (ESD) structure. The first Zener diode and the first steering diodes are configured to respond to a positive ESD pulse, and the second Zener diode and the second steering diode are configured to respond to a negative ESD pulse. The steering diodes are configured to have low capacitances and the Zener diodes are configured to provide enhanced ESD protection. Other related examples and methods are disclosed herein.