Line Sensor Degradation Evaluation Using Dual-Spectrometer Wavelengths

Solution Overview

Problem

Semiconductor exposure apparatuses face challenges in maintaining resolution due to chromatic aberrations caused by wide spectral linewidths of KrF and ArF excimer laser light, leading to decreased performance and the need for frequent replacement of line sensors beyond their shot limits without proper degradation assessment.

Innovation Solution

A sensor degradation evaluation method that uses a processor to assess the degradation of line sensors by measuring interference fringes from spectrometers with different resolutions, comparing degradation parameters to thresholds, and determining the necessity of sensor replacement based on measured data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If line sensors are replaced frequently to maintain measurement accuracy, then measurement precision is improved, but productivity decreases due to unnecessary replacements and increased downtime

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidproductivity

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The system performs preliminary degradation evaluation by acquiring sensitivity distribution data and calculating degradation parameters before the sensor reaches its shot limit. This allows proactive identification of sensors that actually need replacement, preventing unnecessary replacements and maintaining productivity while ensuring measurement accuracy when degradation becomes significant

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system establishes a feedback loop where degradation parameters are continuously evaluated and compared against thresholds. This feedback mechanism enables dynamic decision-making about sensor replacement, replacing sensors only when degradation exceeds acceptable levels, thus optimizing both measurement precision and productivity

Inventive Principle:

Principle #23Feedback

2Productivity

If sensor replacement is delayed beyond shot limits, then productivity is improved by reducing downtime, but measurement precision deteriorates due to degraded sensors

Engineering Contradiction:

ImproveproductivityVSAvoidmeasurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary degradation evaluation by acquiring sensitivity distribution data and calculating degradation parameters before the sensor reaches its shot limit. This allows proactive identification of sensors that actually need replacement, preventing unnecessary replacements and maintaining productivity while ensuring measurement accuracy when degradation becomes significant

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system establishes a feedback loop where degradation parameters are continuously evaluated and compared against thresholds. This feedback mechanism enables dynamic decision-making about sensor replacement, replacing sensors only when degradation exceeds acceptable levels, thus optimizing both measurement precision and productivity

Inventive Principle:

Principle #23Feedback

3Device complexity

If degradation evaluation is not performed, then device complexity is reduced, but loss of information increases due to undetected sensor degradation

Engineering Contradiction:

Improvedevice complexityVSAvoiddegradation information

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The system extracts only the essential degradation evaluation functionality from the overall measurement system. By focusing specifically on acquiring sensitivity distribution data and calculating degradation parameters, the system adds minimal complexity while effectively detecting sensor degradation and preventing information loss

Inventive Principle:

Principle #2Taking out (Extraction)

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 allows for the accurate evaluation of line sensor degradation, enabling timely replacement and maintaining high measurement accuracy while reducing unnecessary replacements, thus optimizing the performance and cost-effectiveness of semiconductor exposure apparatuses.

Implementation Method 1

measuring interference fringes from spectrometers with different resolutions

Methodology Applied

Scientific EffectInterference: Interference

Data Source

PatentUS11808629B2Sensor degradation evaluation method

Publication Date: 2023.11.07 GIGAPHOTON INC

AI summary

A sensor degradation evaluation method according to an aspect of the present disclosure includes an evaluation step of evaluating degradation of at least one of a sensor for coarse measurement that receives interference fringes produced by a spectrometer for coarse measurement and a sensor for fine measurement that receives interference fringes produced by a spectrometer for fine measurement, and the evaluation step includes causing a plurality of kinds of laser light having wavelengths different from one another to be sequentially incident on the spectrometer for coarse measurement and the spectrometer for fine measurement and acquiring a coarse-measurement wavelength and a fine-measurement wavelength on a wavelength basis from a plurality of the received interference fringes, acquiring a degradation parameter on a wavelength basis from the coarse-measurement wavelength and the fine-measurement wavelength on a wavelength basis, and comparing the degradation parameter on a wavelength basis with a threshold.