Parallel SCR ESD Protection Circuit to Prevent Latch-Up

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Solution Overview

Problem

The design of Electro-Static discharge (ESD) protection circuits for semiconductor devices faces challenges in high levels of integration, particularly with SCR components that tend to latch up, leading to continuous electric leakage and potential burnout due to high trigger voltages and low maintaining voltages.

Innovation Solution

The implementation of an ESD protection circuit with two parallel discharge paths, one including a Silicon Controlled Rectifier (SCR) and the other an RC control circuit or PMOS, along with an auxiliary subcircuit to control the SCR, reduces latch-ups and allows for adjustable trigger voltages, thereby enhancing ESD protection and extending device lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an SCR component is used in the ESD protection circuit, then the ESD protection capability is improved, but the circuit tends to latch up causing continuous electric leakage and potential burnout

Engineering Contradiction:

ImproveESD protection capabilityVSAvoidlatch-up and continuous electric leakage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The ESD protection circuit is divided into multiple discharge paths (first discharge path with SCR, second discharge path with other protection components) that operate independently. This segmentation allows the circuit to distribute the discharge current across multiple paths, preventing any single path from experiencing excessive current that would cause latch-up, while maintaining effective ESD protection capability.

Inventive Principle:

Principle #1Segmentation

2Reliability

If a single discharge path is used, then the circuit complexity is reduced, but the ESD protection capability and reliability are insufficient

Engineering Contradiction:

ImproveESD protection capabilityVSAvoidcircuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The circuit merges multiple discharge paths with different protection mechanisms into a unified ESD protection structure. The first discharge path uses SCR for high-voltage ESD protection, while the second discharge path uses alternative protection components for complementary protection. This merging provides enhanced reliability and multi-layer protection without requiring completely separate circuit systems.

Inventive Principle:

Principle #5Merging (Combining)

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 achieves low trigger voltage, reduced electric leakage, adjustable trigger voltage, and high ESD capability, ensuring effective protection against static electricity while minimizing device damage and maintaining normal circuit operation.

Implementation Method 1

The first discharge path and the second discharge path are used for discharging electrostatic charges

Methodology Applied

Scientific EffectElectro-static discharge: Electrostatic Discharge

Implementation Method 2

At least one of the first discharge path and the second discharge path includes a Silicon Controlled Rectifier (SCR)

Methodology Applied

Scientific EffectSilicon Controlled Rectifier conduction:

Data Source

PatentUS11848322B2Electro-static discharge protection circuit and semiconductor device

Publication Date: 2023.12.19 CHANGXIN MEMORY TECH INC

AI summary

An Electrostatic Discharge (ESD) protection circuit includes a first discharge path and a second discharge path. The first discharge path is located between a first potential terminal and a second potential terminal. The second discharge path is located between the first potential terminal and the second potential terminal, and is connected to the first discharge path in parallel. The first discharge path and the second discharge path are used for discharging electrostatic charges. At least one of the first discharge path and the second discharge path includes a Silicon Controlled Rectifier (SCR).