Imaging Sensor Rejuvenation via Controlled Thermal Cycling

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Solution Overview

Problem

Exposure to extreme ultraviolet (EUV) or deep ultraviolet (DUV) light causes degradation of imaging sensors in semiconductor inspection tools, leading to reduced throughput and inefficiency, with existing solutions like cryogenic cooling being impractical for large area, high-speed sensors and sensor replacement resulting in increased downtime.

Innovation Solution

A rejuvenation system that selectively illuminates the imaging sensor with near infrared, visible, or near ultraviolet light during non-operation phases to heat the sensor, reversing degradation without removing it from the system, using a controller to monitor and adjust the illumination power to maintain optimal temperature for rejuvenation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cryogenic cooling is used to mitigate imaging sensor degradation, then sensor degradation is reduced, but device complexity and cost increase significantly

Engineering Contradiction:

Improveimaging sensor performanceVSAvoidcooling system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent converts the harmful effect of heat generation during sensor operation into a beneficial rejuvenation process. By illuminating the sensor with light during non-imaging periods, the sensor is heated to temperatures that reverse degradation effects, thus converting thermal harm into therapeutic benefit without requiring active cooling systems

Inventive Principle:

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

Solution Approach 2:

The imaging sensor performs its own rejuvenation by absorbing illumination energy during non-imaging states. The sensor uses its own operational characteristics (light absorption, heat generation) to reverse its own degradation, eliminating the need for external cryogenic cooling infrastructure

Inventive Principle:

Principle #25Self-service

2Reliability

If imaging sensor is replaced upon degradation, then sensor performance is maintained, but productivity decreases due to increased downtime

Engineering Contradiction:

Improvesensor performanceVSAvoidinspection tool throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary rejuvenation action during non-imaging states before degradation becomes critical. By continuously maintaining the sensor through periodic illumination-based rejuvenation during operational windows, the sensor is restored to optimal performance proactively, preventing the need for replacement and avoiding production downtime

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The rejuvenation process occurs continuously during non-imaging periods within the operational cycle. Rather than interrupting production for sensor replacement, the system maintains sensor performance continuously through integrated rejuvenation cycles that occur during normal operational transitions, ensuring uninterrupted productivity

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If large area, high-speed imaging sensors are operated, then productivity increases, but heat generation increases causing thermal load on cooling systems

Engineering Contradiction:

Improveimaging speed and areaVSAvoidsensor heat generation

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The system applies periodic illumination during non-imaging states to heat the sensor to rejuvenation temperatures. This periodic thermal action occurs during operational cycles when the sensor is not capturing images, allowing the sensor to be heated and rejuvenated without interfering with high-speed imaging operations, thus managing thermal load without reducing productivity

Inventive Principle:

Principle #19Periodic action

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 method effectively rejuvenates imaging sensors in-situ, reducing downtime and maintaining efficiency by reversing degradation without the need for cryogenic cooling or frequent sensor replacements, allowing for more frequent and efficient operation of inspection tools.

Implementation Method 1

A rejuvenation system that selectively illuminates the imaging sensor with near infrared, visible, or near ultraviolet light during non-operation phases to heat the sensor, reversing degradation

Methodology Applied

Scientific EffectPhotothermal heating: Heating

Data Source

PatentUS10096478B2System and method for rejuvenating an imaging sensor degraded by exposure to extreme ultraviolet or deep ultraviolet light

Publication Date: 2018.10.09 KLA CORP

AI summary

The present invention for imaging sensor rejuvenation may include a rejuvenation illumination system configured to selectably illuminate a portion of an imaging sensor of an imaging system with illumination suitable for at least partially rejuvenating the imaging sensor degraded by exposure to at least one of extreme ultraviolet light or deep ultraviolet light; and a controller communicatively coupled to the rejuvenation illumination system and configured to direct the rejuvenation illumination system to illuminate the imaging sensor for one or more illumination cycles during a non-imaging state of the imaging sensor.