Semiconductor Integrated Circuit Discharge Circuit for ESD Protection

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Solution Overview

Problem

In semiconductor integrated circuit devices with multiple power-supply regions operating at different voltages, the potential difference between signal and power-supply wirings becomes excessively large during electrostatic discharge tests, leading to potential gate damage in MOSFETs, particularly due to increased parasitic capacitance and slow discharge rates.

Innovation Solution

Incorporating a discharge circuit and switch circuit configuration that selectively supplies voltage to power-supply wirings, with clamp circuits to manage voltage differences and reduce parasitic capacitance effects, thereby preventing excessive potential differences and enhancing discharge efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple power-supply regions operating at different voltages are integrated on one semiconductor chip, then circuit functionality and power management are improved, but the potential difference between signal and power-supply wirings increases, leading to electrostatic breakdown risk

Engineering Contradiction:

Improvecircuit functionalityVSAvoidelectrostatic breakdown risk

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

A discharge circuit is introduced as an intermediary component between the signal wiring and the first power-supply wiring. This discharge circuit includes a discharge element that provides a controlled discharge path, preventing excessive potential differences during electrostatic discharge events. The discharge circuit acts as a mediator that safely manages the voltage differences inherent in multi-power-supply configurations without requiring reduction of the power-supply voltage differences themselves.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the harmful effect of electrostatic discharge into a controlled and beneficial process. By providing a dedicated discharge path through the discharge circuit, the potentially damaging electrostatic energy is redirected through a safe route that protects the MOSFET gate. The discharge element allows controlled energy dissipation, transforming the harmful electrostatic breakdown risk into a manageable discharge process.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Speed

If parasitic capacitance in power-supply wirings is reduced to improve discharge rate, then electrostatic discharge performance is improved, but the complexity of wiring design and manufacturing increases

Engineering Contradiction:

Improvedischarge rateVSAvoidwiring design complexity

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The discharge circuit is segmented into distinct functional components: a discharge element and a control circuit. This segmentation allows the discharge function to be implemented as a separate, modular unit rather than requiring complex modifications to the power-supply wiring itself. The discharge element can be implemented as a discrete component or integrated circuit, simplifying the overall wiring design while achieving the desired discharge rate.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The discharge circuit is designed to automatically activate during electrostatic discharge events without requiring external control or complex wiring adjustments. The discharge element self-regulates the discharge process, and the control circuit automatically detects and responds to electrostatic conditions. This self-service mechanism eliminates the need for complex manual wiring design adjustments to optimize discharge performance.

Inventive Principle:

Principle #25Self-service

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 effectively reduces the occurrence of electrostatic breakdown in MOSFETs by managing voltage differences and improving discharge rates, thus protecting the semiconductor integrated circuit device from damage during electrostatic discharge tests.

Implementation Method 1

a discharge circuit for discharging a charge in the first wiring

Methodology Applied

Scientific EffectElectrostatic discharge: Electrostatic Discharge

Implementation Method 2

clamp circuits to manage voltage differences and reduce parasitic capacitance effects, thereby preventing excessive potential differences

Methodology Applied

Scientific EffectClamping effect:

Data Source

PatentUS10090829B2Semiconductor integrated circuit device

Publication Date: 2018.10.02 RENESAS ELECTRONICS CORP

AI summary

A semiconductor integrated circuit device is provided with first and second regions that are operated by mutually different voltages, and a signal wiring that supplies a signal from the first region to the second region. The second region includes a circuit that is connected to between a first wiring to which a voltage is selectively supplied and a third terminal to which a voltage is supplied, and is operated by a differential voltage between the voltage in the first wiring and the voltage supplied to the third terminal, and a discharge circuit for discharging a charge in the first wiring. By using the discharge circuit, the potential difference between the signal wiring and the first wiring is prevented from becoming larger, and thus makes it possible to reduce damages of the circuit included in the second region.