Checkerboard Alignment Mark for Distortion-Resistant Position Detection

Solution Overview

Problem

Existing alignment marks on substrates with line-and-space patterns suffer from distortion or measurement signal inaccuracies due to relative position variations, leading to alignment issues in semiconductor manufacturing processes.

Innovation Solution

The alignment mark is designed with a checkerboard pattern of rectangular components, where each component's length is an odd multiple of the line-and-space pattern's half pitch, ensuring line-symmetry, which enhances detection accuracy by minimizing false signal components and improving measurement precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an alignment mark is arranged on a substrate with a line-and-space pattern, then alignment functionality is provided, but distortion or measurement signal inaccuracies occur due to relative position variations

Engineering Contradiction:

Improvealignment measurement accuracyVSAvoidmeasurement signal stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The alignment mark employs a specific asymmetric design where the first component has a length in the first direction that is an odd multiple of the half pitch of the line-and-space pattern. This asymmetric configuration ensures line-symmetry of the overall alignment mark with respect to a straight line passing through its center, which eliminates false signal components and prevents measurement inaccuracies that would otherwise occur due to relative position variations between the alignment mark and the line-and-space pattern.

Inventive Principle:

Principle #4Asymmetry

2Ease of manufacture

If a conventional alignment mark design is used, then manufacturing simplicity is maintained, but alignment precision deteriorates due to distortion in measurement signals

Engineering Contradiction:

Improvealignment mark fabricationVSAvoidsubstrate alignment precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The alignment mark employs a specific asymmetric design where the first component has a length in the first direction that is an odd multiple of the half pitch of the line-and-space pattern. This asymmetric configuration ensures line-symmetry of the overall alignment mark with respect to a straight line passing through its center, which eliminates false signal components and prevents measurement inaccuracies that would otherwise occur due to relative position variations between the alignment mark and the line-and-space pattern.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS20250336843A1Alignment mark, alignment mark pair, substrate, and manufacturing method of semiconductor device

Publication Date: 2025.10.30 CANON KK

AI summary

An alignment mark formed by a plurality of first components each having a rectangular shape and a plurality of second components each having a rectangular shape are arrayed in a checkerboard pattern. Each first component is formed from a flat region. Each second component is formed from a line-and-space pattern having a periodicity in a first direction. A length of the first component in the first direction is an odd multiple of a half pitch of the line-and-space pattern. The line-and-space pattern of each second component is line-symmetric with respect to a straight line passing through a center of the second component in parallel to a second direction orthogonal to the first direction.