Non-Contact Detection System for Semiconductor Overlay Precision

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Solution Overview

Problem

The increasing demand for higher overlay accuracy in semiconductor device manufacturing, particularly with finer integrated circuits, is challenging due to the limitations of existing alignment technologies, which face difficulties in increasing throughput while maintaining precision with Enhanced Global Alignment (EGA) methods.

Innovation Solution

A holding apparatus that supports a detection system for precise movement in a horizontal plane, allowing non-contact operation to minimize frictional influences, combined with a position detection apparatus that uses attraction and repulsion forces to maintain clearance and drive the detection system, enabling high-precision positioning and pattern formation on sensitive objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of sample shot areas is increased to improve computation accuracy in EGA, then measurement precision is improved, but productivity decreases

Engineering Contradiction:

Improvecomputation accuracyVSAvoidthroughput

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The detection system is divided into multiple independent detection units that can simultaneously detect marks in different shot areas. This parallel detection approach allows multiple sample shots to be measured at the same time, thereby improving computation accuracy without reducing throughput.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent replaces mechanical contact-based detection systems with a non-contact detection system that uses electromagnetic fields (such as optical or electromagnetic radiation) to detect marks. This eliminates frictional forces that would otherwise interfere with detection precision and allows for faster, non-contact measurement of multiple marks simultaneously.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If a detection system is driven in contact with the support device, then ease of operation is improved, but manufacturing precision deteriorates due to frictional force

Engineering Contradiction:

Improveease of drivingVSAvoidpositioning precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical contact-driven systems with a non-contact drive system that uses electromagnetic forces (such as electromagnetic induction or electrostatic forces) to move the detection system. This eliminates frictional forces entirely, allowing the detection system to move smoothly and precisely without the positioning errors that would otherwise occur due to friction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental operating parameter of the drive system from mechanical contact force to electromagnetic force. This parameter change allows the detection system to be driven without physical contact, thereby eliminating friction and achieving high-precision positioning while maintaining ease of operation through electromagnetic control.

Inventive Principle:

Principle #35Parameter changes

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 solution enhances the precision and throughput of pattern formation on semiconductor wafers by allowing highly precise movement and positioning of detection systems, improving the overlay accuracy and productivity in microdevice manufacturing.

Implementation Method 1

a drive device which drives the detection system supported via a predetermined clearance by the support device at least in a uniaxial direction in a horizontal plane

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

allowing non-contact operation to minimize frictional influences

Methodology Applied

Scientific EffectFriction reduction through non-contact operation: Air Lubrication

Data Source

PatentUS8432534B2Holding apparatus, position detection apparatus and exposure apparatus, moving method, position detection method, exposure method, adjustment method of detection system and device manufacturing method

Publication Date: 2013.04.30 NIKON CORP

AI summary

By a force generation device which can generate a magnetic attraction and gas static pressure between a detection system provided on a lower surface side of an FIA surface plate and a surface plate, a predetermined clearance is formed between the detection system and the surface plate, and in a state where the clearance is formed (a floating state), the detection system is driven by a drive device in at least an uniaxial direction within a horizontal plane. Therefore, because the detection system is in a non-contact state to the base platform, movement (positioning) of the detection system with high precision becomes possible. Further, by setting an attraction larger than a repulsion generated by the force generation device, the detection system can be fixed (landed) in a state positioned with high precision.