Photon Emission Imaging for IC Contention Current Analysis

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Solution Overview

Problem

Integrated circuits (ICs) face risks of interconnect wire damage due to increased current density and contention currents, which are not typically considered during design, necessitating a method to analyze and control these currents during testing.

Innovation Solution

A method and apparatus that generates an image from detected photon emissions from the IC, allowing for the determination of current intensities and estimation of contention current magnitudes by comparing known and unknown current intensities using a system comprising a test unit, computer, and emission microscope, enabling identification and analysis of contention currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If transistor gate lengths are reduced to 65 nanometers or smaller, then manufacturing precision and device density are improved, but current density on interconnect wires increases causing damage risk

Engineering Contradiction:

Improvetransistor gate lengthVSAvoidcurrent density on interconnect wires

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by performing photon emission imaging and current analysis during the testing phase before actual deployment. This allows identification of high current density regions and potential contention current sources in advance, enabling design modifications or protective measures to be implemented before the IC enters service, thus preventing interconnect wire damage from occurring

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces direct electrical measurement methods with optical detection using photon emission imaging. By substituting electrical probes with optical sensors that detect photons emitted from high current regions, the system avoids adding electrical test structures that could themselves become sources of contention current or interfere with the delicate interconnect wires being measured

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If contention current is not considered during design, then device complexity is reduced, but reliability deteriorates due to undetected high current regions

Engineering Contradiction:

Improvedesign considerationsVSAvoidinterconnect wire integrity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies self-service by utilizing the IC's own operational current to generate photons that serve as the measurement signal. The contention current that would normally be harmful unintentionally creates visible photon emissions that reveal its presence and location, allowing the system to detect reliability issues without requiring separate test current sources or additional design complexity

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent converts the harmful contention current into a beneficial measurement signal. The very high current density that poses a damage risk also generates intense photon emissions that make the problem visible and measurable. By detecting these emissions, the system identifies problematic regions so they can be addressed, transforming an invisible threat into a detectable and manageable condition

Inventive Principle:

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

3Measurement precision

If photon emission imaging is used to detect current, then measurement capability is improved, but device complexity increases due to additional testing equipment

Engineering Contradiction:

Improvecurrent detection capabilityVSAvoidtesting equipment

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces photons as an intermediary between the electrical current in the IC and the measurement system. Instead of directly measuring electrical parameters with complex electrical test equipment, the system uses photons emitted from high current regions as an intermediate carrier of information, which can be detected with relatively simple optical sensors and imaged to create current distribution maps

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Effectively identifies and estimates contention currents, reducing the risk of interconnect wire damage by providing a systematic approach to analyze current in ICs under test, thereby enhancing the reliability of semiconductor device testing.

Implementation Method 1

An image from detected photon emissions from the integrated circuit is generated

Methodology Applied

Scientific EffectPhoton emission: Luminescence

Data Source

PatentUS7453273B1Method and apparatus for analyzing current in an integrated circuit under test

Publication Date: 2008.11.18 XILINX INC

AI summary

Method and apparatus for analyzing current in an integrated circuit under test is described. In one example, an image from detected photon emissions from the integrated circuit is generated. A first intensity of the photon emissions at a first region in the image indicative of a first current having a known magnitude is determined. A second intensity of the photon emissions at a second region in the image indicative of a second current is determined. A magnitude of the second current is estimated from the first intensity, the second intensity, and the known magnitude of the first current.