Multi-layered Moiré Targets for Semiconductor Misregistration Measurement

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Solution Overview

Problem

Existing methods for measuring misregistration in the manufacture of semiconductor devices are inadequate, as they fail to accurately calculate misregistration between multiple layers on a semiconductor device wafer.

Innovation Solution

A multi-layered moiré target is introduced, comprising periodic structure stacks formed on a semiconductor device wafer. This target includes multiple layers, each with specific periodic structures and pitches, allowing for the calculation of misregistration between layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing methods for measuring misregistration are used, then the measurement process is simple, but the accuracy of misregistration calculation between multiple layers is insufficient

Engineering Contradiction:

Improvemisregistration calculation accuracyVSAvoidmeasurement target structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The measurement target is divided into multiple independent periodic structure stacks, each corresponding to different layer combinations. Each stack contains periodic structures from specific layers that can be independently analyzed to calculate misregistration between those layers, enabling multi-layer misregistration measurement through segmented analysis

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extends the measurement from two-dimensional planar targets to three-dimensional stacked structures. By arranging periodic structures in vertical stacks across multiple layers with different pitches, the system captures misregistration information in the depth dimension, enabling accurate calculation of misregistration between multiple layers rather than just a single plane

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If multi-layered moiré target with multiple periodic structure stacks is used, then misregistration between multiple layers can be accurately measured, but the device complexity increases

Engineering Contradiction:

Improvelayer alignment precisionVSAvoidperiodic structure stack configuration

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The periodic structure stacks are designed to serve multiple measurement functions simultaneously. Each stack can measure misregistration between different layer combinations, and the same target structure enables calculation of both x-direction and y-direction misregistration, reducing the need for separate measurement targets for different purposes

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The measurement system embeds multiple measurement capabilities within a nested hierarchical structure. Individual periodic structures are nested within stacks, which are arranged in groups, with each level contributing to the overall misregistration calculation. This nested arrangement allows compact integration of complex measurement functionality

Inventive Principle:

Principle #7Nested doll (Nesting)

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

The multi-layered moiré target effectively measures misregistration between multiple layers, improving the accuracy and efficiency of semiconductor device manufacturing by enabling precise alignment of layers.

Implementation Method 1

Multi-layered moiré targets and methods for using the same in measuring misregistration of semiconductor devices

Methodology Applied

Scientific EffectMoiré effect: Moiré Effect

Data Source

PatentUS12204254B2Multi-layered moiré targets and methods for using the same in measuring misregistration of semiconductor devices

Publication Date: 2025.01.21 KLA CORP

AI summary

A multi-layered moir target, useful in the calculation of misregistration between at least first, second and third layers being formed on a semiconductor device wafer, including at least one group of periodic structure stacks, each including a first stack, including a first stack first periodic structure (S1P1) having an S1P1 pitch along a first axis, a second stack, including a second stack first periodic structure (S2P1) having an S2P1 pitch along a second axis and a third stack, including a third stack first periodic structure (S3P1) having an S3P1 pitch along a third axis, the first axis being parallel to an x-axis or a y-axis, and at least one of the stacks including a second periodic structure having a second periodic structure pitch along at least one fourth axis parallel to the first axis and co-axial with one of the axes.