Lithographic Measurement Target Grid for Scribe Lane Space

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Solution Overview

Problem

Lithographic apparatuses require significant 'real estate' on substrates for overlay measurements due to the need for multiple target positions, which can be inefficient and wasteful of space, especially in multi-layer device manufacturing processes.

Innovation Solution

A lithographic apparatus and method that utilizes a grid of conducting material with openings smaller than the measurement wavelength for the substrate, allowing the reuse of measurement target locations by obscuring earlier targets, thus reducing the number of necessary positions for measurement targets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple separate measurement targets are used for different measurement processes, then measurement accuracy is maintained by avoiding interference, but substrate space consumption increases significantly

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidsubstrate space

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges multiple measurement targets into a single shared measurement target that can serve multiple measurement processes. The measurement target includes multiple measurement regions that can be sequentially activated, allowing overlay measurements, CD measurements, and alignment measurements to all use the same physical location on the substrate, thereby reducing substrate space requirements while maintaining measurement accuracy through process-specific region activation

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The measurement target is designed with multi-functionality to serve multiple measurement purposes. Different measurement regions within the same target can be activated depending on the measurement process being performed, making a single target structure universal for various measurement needs including overlay, critical dimension, and alignment measurements

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If dedicated measurement regions are allocated for each process, then measurement precision is ensured without interference, but device complexity increases due to multiple target positions

Engineering Contradiction:

Improveoverlay measurement precisionVSAvoidmeasurement target complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The measurement target is segmented into multiple distinct measurement regions, each optimized for specific measurement types. The target includes a first measurement region for overlay measurements, a second measurement region for CD measurements, and a third measurement region for alignment measurements. This segmentation allows precise measurements for each process while managing complexity through systematic regional division

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The measurement target is pre-configured with all necessary measurement regions before the measurement processes begin. The target structure is designed in advance with designated regions for different measurement types, allowing the measurement system to simply activate the appropriate pre-prepared region based on the measurement process, thereby reducing operational complexity

Inventive Principle:

Principle #10Preliminary action

3Reliability

If separate scribe lane spaces are used for each measurement process, then measurement reliability is maintained by excluding errors, but manufacturing efficiency decreases due to space constraints

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidmanufacturing efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The measurement regions are designed to be temporarily activated and then effectively 'discarded' or deactivated after their specific measurement process is complete. The same physical measurement target location can then be 'recovered' and reused for subsequent measurement processes by activating different measurement regions, thereby reducing the need for permanent dedicated spaces for each measurement type and improving manufacturing efficiency

Inventive Principle:

Principle #34Discarding and recovering

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

This approach minimizes the space required for overlay measurements, allowing for more efficient use of substrate space and enabling the reuse of measurement locations, thereby reducing the complexity and cost associated with multiple target positions.

Implementation Method 1

transforming the measurement target in a grid of conducting material, the grid having grid openings which are smaller than the first wavelength

Methodology Applied

Scientific EffectAbsorption of electromagnetic radiation: Absorption (EM radiation)

Data Source

PatentUS7486408B2Lithographic apparatus and device manufacturing method with reduced scribe lane usage for substrate measurement

Publication Date: 2009.02.03 ASML NETHERLANDS BV

AI summary

In a device manufacturing method and lithographic apparatus wherein a pattern is transferred from a patterning device onto a substrate, a measurement target is provided on the substrate in a process enabling execution of a substrate measurement using radiation of a first wavelength. Subsequently the measurement target is transformed in a grid of conducting material, the grid having grid openings which are smaller than the first wavelength. The space in the scribe lane where the measurement target was, is now shielded and may be used again in further layers or processing steps of the substrate.