Dual-Dopant Guard Ring Structure for Higher Holding Voltage

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Solution Overview

Problem

Existing guard ring designs for FinFET circuit devices struggle to balance the reduction of interference between adjacent devices and the increase of holding voltage during electro-static discharge (ESD) events, often requiring increased spacing that compromises chip area efficiency.

Innovation Solution

A dual-dopant type guard ring structure where an inner set of guard rings with one dopant type is in contact with an outer set of guard rings of opposite dopant type, reducing the need for spacing and enhancing energy dissipation during ESD events while maintaining device isolation and reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the space between adjacent guard rings is increased, then the holding voltage of the circuit device is increased, but the chip area is increased

Engineering Contradiction:

Improveholding voltageVSAvoidchip area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent changes the dopant type parameter of guard rings from uniform to alternating (n-type and p-type alternating). This parameter change enables the guard rings to effectively channel ESD current through opposite dopant type interactions, increasing holding voltage without requiring increased spacing between rings, thus resolving the contradiction between reliability and chip area.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite guard ring structure by alternating different dopant types (n-type and p-type) in adjacent guard rings. This composite approach forms a more effective ESD protection system where the alternating dopant types work together to channel and dissipate energy, achieving higher holding voltage within the same chip area.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the space between adjacent guard rings is increased, then the holding voltage of the circuit device is increased, but the interference reduction between adjacent devices is compromised

Engineering Contradiction:

Improveholding voltageVSAvoidinterference between adjacent devices

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

By changing the dopant type parameter to alternate between n-type and p-type in adjacent guard rings, the patent enhances the guard rings' ability to channel ESD current while maintaining tight spacing. This allows simultaneous achievement of high holding voltage and effective interference reduction between adjacent devices.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the potentially harmful ESD current into a controlled flow by using alternating dopant types to create effective current channeling paths. The ESD energy is beneficially directed through the alternating n-type and p-type guard rings to safe dissipation paths, protecting adjacent devices while maintaining compact spacing.

Inventive Principle:

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

3Ease of manufacture

If uniform dopant type guard rings are used, then the manufacturing process is simplified, but the energy dissipation capability during ESD events is reduced

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidenergy dissipation capability

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent changes the dopant type parameter from uniform to alternating patterns. While this increases manufacturing complexity slightly, it dramatically improves energy dissipation capability during ESD events by creating more effective current channeling paths through the alternating n-type and p-type regions, allowing better control of high-energy discharge.

Inventive Principle:

Principle #35Parameter changes

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 dual-dopant guard ring structure increases holding voltage, reduces the risk of damage during ESD events, and minimizes interference between neighboring devices without increasing chip area, thereby improving the overall performance and efficiency of the circuit device.

Implementation Method 1

Guard rings also help to dissipate energy in a circuit device during an electro-static discharge (ESD) event. An ESD event occurs when a large flow of electricity passes from one element to another.

Methodology Applied

Scientific EffectElectro-static discharge (ESD): Electrostatic Discharge

Implementation Method 2

The dual-dopant guard ring structure where an inner set of guard rings with one dopant type is in contact with an outer set of guard rings of opposite dopant type, reducing the need for spacing and enhancing energy dissipation during ESD events

Methodology Applied

Scientific EffectElectrical field: Electric Field

Data Source

PatentUS12471326B2Guard ring and circuit device

Publication Date: 2025.11.11 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A circuit device includes core circuitry. The circuit device further includes a first plurality of guard rings having a first dopant type, wherein the first plurality of guard rings is around a periphery of the core circuitry. The circuit device further includes a second plurality of guard rings having a second dopant type, wherein the second dopant type is opposite to the first dopant type, and at least one guard ring of the second plurality of guard rings is around a periphery of at least one guard ring of the first plurality of guard rings.