Slope Circumferential Walls for Substrate Holding Precision

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Solution Overview

Problem

Conventional substrate holding apparatuses face limitations in precise adjustment of polishing profiles, particularly at the peripheral portions of substrates, due to the design of elastic membranes with inner circumferential walls that can lead to contact issues and restricted pressure chamber width, affecting the uniformity of polishing.

Innovation Solution

The substrate holding apparatus features an elastic membrane with slope circumferential walls that extend radially inwardly from lower ends to upper ends, eliminating horizontal portions and allowing for precise adjustment of pressure chambers, enabling smaller pressure chamber widths and preventing contact between adjacent walls, thus allowing for precise control of polishing profiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional elastic membrane design with horizontal portions is used, then the structure is simple to manufacture, but the pressure chamber width is restricted and wall contact occurs, limiting polishing profile adjustment precision

Engineering Contradiction:

Improvepolishing profile adjustment precisionVSAvoidelastic membrane structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The elastic membrane is designed with slope circumferential walls that extend radially inwardly from lower ends to upper ends, eliminating horizontal portions. This curved/sloped geometry prevents contact between adjacent walls while enabling smaller pressure chamber widths, thereby improving polishing profile adjustment precision without the contact issues that plague conventional designs.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If pressure difference between adjacent pressure chambers is increased, then polishing profile adjustment range is improved, but inner circumferential walls contact each other, limiting further adjustment

Engineering Contradiction:

Improvepolishing profile adjustment rangeVSAvoidwall contact prevention

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The slope circumferential walls are designed to extend radially inwardly throughout their entire length, creating a geometric configuration where adjacent walls remain separated even under high pressure differences. This prevents wall contact while maintaining the ability to adjust polishing profiles across a wide range, resolving the contradiction between adjustment range and contact prevention.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Area of stationary object

If inner circumferential walls are made to extend upwardly from contact portion, then pressure chambers are formed for polishing, but horizontal portions cause adjacent walls to contact, restricting pressure chamber width

Engineering Contradiction:

Improvepressure chamber widthVSAvoidpolishing uniformity

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The slope circumferential walls eliminate horizontal portions and extend radially inwardly from lower ends to upper ends, allowing pressure chambers to maintain adequate width without causing adjacent walls to contact. This geometric modification enables better polishing uniformity while preserving sufficient pressure chamber dimensions for effective polishing.

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 enables precise adjustment of polishing profiles across the substrate, including the peripheral areas, by preventing contact between inner circumferential walls and allowing for smaller pressure chamber widths, thereby enhancing the uniformity and effectiveness of the polishing process.

Implementation Method 1

This pressure chamber is supplied with a fluid, such as air, to press the wafer through the elastic membrane with a fluid pressure

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

an elastic membrane with slope circumferential walls that extend radially inwardly from lower ends to upper ends, eliminating horizontal portions and allowing for precise adjustment of pressure chambers

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11179823B2Substrate holding apparatus, elastic membrane, polishing apparatus, and method for replacing elastic membrane

Publication Date: 2021.11.23 EBARA CORP

AI summary

A substrate holding apparatus which can adjust polishing profile precisely is disclosed. The substrate holding apparatus includes an elastic membrane that forms a plurality of pressure chambers for pressing a substrate, and a head body to which the elastic membrane is coupled. The elastic membrane includes a contact portion to be brought into contact with the substrate for pressing the substrate against a polishing pad, an edge circumferential wall extending upwardly from a peripheral edge of the contact portion, and a plurality of inner circumferential walls arranged radially inwardly of the edge circumferential wall and extending upwardly from the contact portion. At least two adjacent inner circumferential walls of the plurality of inner circumferential walls include slope circumferential walls inclined radially inwardly. The slope circumferential walls are inclined radially inwardly in their entirety from their lower ends to upper ends, and extend upwardly.