Helical Electrostatic Chuck Layout for Uniform Wafer Suction

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Solution Overview

Problem

In electrostatic chucks with alternately meshed belt-shaped tines, the installation of lift pin holes disrupts the regularity of the electrode pattern, leading to variations in suction power on the wafer placement surface.

Innovation Solution

The electrostatic chuck is designed with a ceramic plate divided into areas equal to the number of through holes, featuring pairs of positive and negative helical electrode portions that cover each division area in parallel, allowing the electrodes to maintain regularity without detouring around lift pin holes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If belt-shaped tines are used for electrodes, then the electrode structure is simple and easy to manufacture, but the electrode pattern regularity is disrupted when lift pin holes are installed

Engineering Contradiction:

Improveelectrode structure simplicityVSAvoidelectrode pattern regularity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The ceramic plate is divided into multiple division areas, with each area containing a complete pair of positive and negative helical electrode portions. This segmentation allows each local electrode pattern to maintain regularity independently, solving the problem of pattern disruption caused by lift pin holes while keeping the overall structure manageable and manufacturable.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The electrode portions are designed with helical (curved) shapes instead of straight belt-shaped tines. This curvature allows the electrodes to wrap around and accommodate the presence of lift pin holes without disrupting the overall pattern regularity, while maintaining ease of manufacturing through standard patterning processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If tines are formed in arc shape to avoid lift pin holes, then the lift pin holes can be installed, but the regularity of electrode pattern is disturbed causing variation in suction power

Engineering Contradiction:

Improveability to install lift pin holesVSAvoidsuction power consistency

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

By dividing the plate into multiple division areas, each containing a complete electrode pair, the patent ensures that lift pin holes can be installed in the spaces between division areas without affecting the regularity within each area. This segmentation isolates the impact of lift pin holes, maintaining suction power consistency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each division area is designed with uniform helical electrode portions that maintain consistent patterns and spacing. This local uniformity ensures consistent electrostatic field distribution and suction power within each area, while the overall structure accommodates lift pin holes in the interstitial spaces.

Inventive Principle:

Principle #3Local quality

3Device complexity

If alternately meshed belt-shaped tines are used, then the electrode structure is compact, but installing lift pin holes requires changing tine shapes which increases device complexity

Engineering Contradiction:

Improveelectrode structure complexityVSAvoidability to accommodate lift pin holes

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The plate is divided into multiple division areas, each containing a complete pair of helical electrode portions. This segmentation allows lift pin holes to be positioned in the spaces between division areas without requiring modifications to the electrode shapes themselves, thus maintaining structural simplicity while accommodating additional functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The helical shape of the electrode portions provides a compact, space-efficient design that naturally accommodates the presence of lift pin holes without requiring arc-shaped modifications. The curved helical pattern maintains compactness while allowing regular, grid-like placement of lift pin holes between division areas.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 design maintains the regularity of the electrode pattern, reducing variations in suction power across the wafer placement surface and ensuring consistent electrostatic holding of wafers.

Implementation Method 1

a pair of positive and negative electrodes provided in the plate to generate an electrostatic force

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentUS12243764B2Electrostatic chuck

Publication Date: 2025.03.04 NGK INSULATORS LTD

AI summary

An electrostatic chuck includes a ceramic plate through holes which penetrate the plate, and a pair of positive and negative electrodes. The plate has division areas virtually divided, which are equal in number to the number of the through holes. The positive electrode and the negative electrode have pairs of positive and negative helical electrode portions, and for each of the division areas, one of the pairs is provided in parallel so as to cover the entirety of the division area from each of a positive electrode start point and a negative electrode start point which are close to one of the through holes. The positive electrode is such that the positive helical electrode portions are connected via outer circumferential portions of the plate, and the negative electrode is such that the negative helical electrode portions are connected via a central portion of the plate.