Sample Clamping Measurement Module for Local Gap Detection

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Solution Overview

Problem

Existing methods for securing samples on sample supports in semiconductor manufacturing are inadequate, leading to uneven clamping, potential defects in pattern formation, compromised inspections, and risks of sample dislodgment or liquid leaks, which can cause apparatus damage and reduce yield and throughput.

Innovation Solution

A module comprising a pin that displaces upon contact with a local sample region and a sensor to measure the distance between the sample and support, providing precise clamping status assessment, combined with capacitive proximity sensors for global averaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a capacitive proximity sensor is used to determine clamping status, then the average distance between sample and clamping electrodes can be measured, but local deviations from the average distance cannot be detected

Engineering Contradiction:
Improveaverage distance measurementVSAvoidlocal distance variation information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent divides the continuous sample surface into discrete measurement points by using multiple pins distributed across the sample. Each pin independently measures the local distance at its specific position, segmenting the overall measurement task into multiple localized measurements that collectively provide complete spatial information about sample-clamp contact.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the sample is not evenly secured to the sample support, then the clamping force distribution becomes non-uniform, but this cannot be detected by existing sensors

Engineering Contradiction:
Improvesample placement flexibilityVSAvoidclamping status verification
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The pin array system enables self-verification of proper sample mounting. As the sample is placed on the sample support, the pins automatically detect whether the sample surface is properly contact the support at multiple locations without requiring external intervention or complex sensing systems.

Inventive Principle:
Principle #25Self-service

3Device complexity

If the clearance gap between assessment apparatus component and sample upper surface is very small (e.g., 50 μm), then the apparatus can operate with compact design, but a loosely secured sample will not fit within the clearance gap

Engineering Contradiction:
Improveapparatus compactnessVSAvoidsample security tolerance
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The pin array performs preliminary verification of sample security before the assessment process begins. By checking that the sample properly contacts the support at multiple points, the system ensures that the sample is securely positioned within the limited clearance gap, preventing operational failures during the assessment process.

Inventive Principle:
Principle #10Preliminary 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

Enables accurate determination of sample clamping across the entire surface, ensuring secure fixation, reducing defects and leaks, and enhancing inspection efficiency and apparatus reliability.

Implementation Method 1

a pin arranged such that, when a sample is placed on the sample support, the pin is displaced by contact with a local region of the sample adjacent to the pin

Methodology Applied
Scientific EffectContact force: Mechanical Force

Implementation Method 2

a capacitive proximity sensor may be used to determine whether the sample is secured by the electrostatic clamp. The capacitive proximity sensor returns a voltage reflecting capacitance between the sample and clamping electrodes of the electrostatic clamp. Because the capacitance is inversely proportional to the distance between the sample and the clamping electrodes

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4679482A1Module, apparatus, and method of using the module
Publication Date: 2026.01.14 ASML NETHERLANDS BV
  • EP4679482A1 patent drawingFigure 1
  • EP4679482A1 patent drawingFigure 2
  • EP4679482A1 patent drawingFigure 3A~4

AI summary

The present invention provides a module for measuring clamping status of a sample on a sample support. The module comprises a pin arranged such that, when a sample is placed on the sample support, the pin is displaced by contact with a local region of the sample adjacent to the pin. The module further comprises a sensor configured to determine a distance between the local region of the sample and the sample support based on movement of the pin.