Microscope Tilt Correction for Accurate Wafer Channel Orientation

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Solution Overview

Problem

Existing methods for measuring and reconstructing the vertical orientation of channels in semiconductor wafers struggle with accurately compensating for sample tilt, leading to misalignment and errors in channel orientation, which affects the yield and performance of manufactured devices.

Innovation Solution

A method that involves measuring the tilt of the sample using a microscope, correcting the sample position or scanning plane to account for the tilt, and reconstructing the volume model to ensure accurate imaging and orientation of vertical structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sample is positioned on the support without tilt measurement, then the positioning is simple, but the channel orientation measurement precision deteriorates due to sample tilt

Engineering Contradiction:

Improvechannel orientation measurement precisionVSAvoidpositioning system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The tilt measurement is performed before the main channel orientation measurement to enable preliminary correction of the sample position or scanning plane, preventing measurement errors from occurring in the first place

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A tilt measurement mechanism acts as an intermediary between the sample positioning system and the main measurement system, providing tilt data that enables correction without requiring complex real-time positioning adjustments

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If the scanning plane is not corrected for tilt, then the scanning process is simple, but the reconstructed volume model accuracy deteriorates

Engineering Contradiction:

Improvevolume model reconstruction accuracyVSAvoidscanning operation simplicity

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The scanning plane is pre-adjusted based on measured tilt values before the actual scanning process, ensuring accuracy without requiring complex real-time corrections during scanning

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of mechanically adjusting the sample holder during scanning, the system uses computational methods to correct the scanning plane coordinates based on measured tilt, replacing mechanical complexity with computational simplicity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If tilt measurement and correction is implemented, then the channel orientation accuracy is improved, but the measurement process time increases

Engineering Contradiction:

Improvechannel orientation accuracyVSAvoidmeasurement process time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system measures tilt at selected locations rather than across the entire sample surface, and only corrects when tilt exceeds a threshold, performing partial correction rather than comprehensive correction to reduce time

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system automatically performs tilt measurement and correction without requiring manual intervention or complex calibration procedures, making the process self-service and efficient

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11915908B2Method for measuring a sample and microscope implementing the method

Publication Date: 2024.02.27 CARL ZEISS SMT GMBH

AI summary

The present invention relates to a method for measuring a sample with a microscope, the method comprising the steps of: measuring a tilt of the sample, correcting an orientation of the sample based on the tilt, and scanning the sample.