Mask Inspection Apparatus E-Beam Array Registration Offset Correction

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Solution Overview

Problem

Current mask inspection technologies face challenges in quickly and accurately inspecting the registration of patterns on masks while detecting defects, often resulting in errors due to positional inaccuracies of e-beam irradiators and stage movements.

Innovation Solution

A mask inspection apparatus and method utilizing an e-beam array with multiple e-beam irradiators and detectors, which calculate offset values to determine the registration of patterns by subtracting positional errors of e-beam irradiators from measured pattern positions, allowing simultaneous defect detection and registration inspection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If e-beam irradiators are used for mask inspection, then defect detection capability is improved, but positional accuracy deteriorates due to e-beam irradiator positioning errors and stage movements

Engineering Contradiction:

Improvedefect detection capabilityVSAvoidpositional accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system measures the actual positions of e-beam irradiators and stage using reference patterns, calculates offset values, and uses these offsets to correct pattern registration measurements. This feedback mechanism compensates for positioning errors and maintains measurement precision despite using e-beam inspection technology.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the reference frame by introducing offset values that account for e-beam irradiator positions and stage movements. By subtracting these offsets from measured pattern positions, the system maintains accurate registration inspection while using e-beam technology for defect detection.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If multiple e-beam irradiators are used to improve inspection speed, then productivity is improved, but device complexity increases

Engineering Contradiction:

Improveinspection speedVSAvoide-beam array complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The inspection system is divided into multiple independent e-beam irradiators that can operate simultaneously on different regions of the mask. Each irradiator inspects its own region independently, and the results are combined to achieve fast complete mask inspection while keeping each individual irradiator relatively simple.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple e-beam irradiators serve dual functions: detecting mask defects and measuring pattern positions for registration inspection. This multi-functionality improves productivity without requiring separate inspection systems, though it does increase overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If e-beam irradiators are positioned quickly to improve inspection efficiency, then productivity is improved, but measurement precision deteriorates due to positioning errors

Engineering Contradiction:

Improveinspection efficiencyVSAvoidpositioning accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary measurement of e-beam irradiator positions and stage locations using reference patterns before actual pattern inspection. These preliminary measurements establish offset values that are stored and used to correct subsequent measurements, enabling fast positioning without sacrificing precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors and measures the positions of e-beam irradiators and stage, calculates offset values from reference patterns, and applies these offsets to correct pattern registration measurements. This real-time feedback ensures measurement precision is maintained even when positioning occurs quickly for productivity.

Inventive Principle:

Principle #23Feedback

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

Enables quick and accurate inspection of pattern registration on masks, reducing errors by accounting for positional inaccuracies of e-beam irradiators and stage movements, thereby improving the reliability of mask inspection processes.

Implementation Method 1

an e-beam irradiator configured to irradiate an e-beam onto the mask and a detector configured to detect electrons emitted from the mask

Methodology Applied

Scientific EffectElectron emission: Electron Beam

Data Source

PatentUS11353413B2Mask inspection apparatuses and methods, and methods of fabricating masks including mask inspection methods

Publication Date: 2022.06.07 SAMSUNG ELECTRONICS CO LTD

AI summary

Mask inspection apparatuses and/or mask inspection methods are provided that enable quick and accurate inspection of a registration of a pattern on a mask while a defect of the mask and the registration of the pattern are inspected simultaneously. The mask inspection apparatus may include a stage configured to receive a mask for inspection; an e-beam array including a plurality of e-beam irradiators configured to irradiate e-beams to the mask and detectors configured to detect electrons emitted from the mask; and a processor configured to process signals from the detectors. A defect of the mask may be detected through processing of the signal and registrations of patterns on the mask may be inspected based on positional information regarding the e-beam irradiators.