Dual-Head Substrate Polishing for Boundary Chipping Removal

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Solution Overview

Problem

The formation of knife edge portions during substrate polishing leads to chipping, which can damage laminated substrates during handling, and existing methods to prevent this, such as forming recesses, often result in additional defects.

Innovation Solution

A polishing apparatus with dual polishing heads, one holding a polishing tool at an acute angle to form a recess and another at a right or obtuse angle to address the polishing boundary, utilizing guide rollers to adjust tape angles for precise polishing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a polishing tool is pressed against the peripheral portion of the substrate to form a recess, then knife edge portion formation is prevented, but chipping occurs at the polishing boundary of the recess

Engineering Contradiction:
Improveresistance to knife edge formationVSAvoidchipping at polishing boundary
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies different polishing tool angles at different locations: an acute angle (first angle) at the peripheral portion to form the recess and prevent knife edge formation, and a right or obtuse angle (second angle) at the polishing boundary to remove chipping. This local differentiation of polishing parameters resolves the contradiction between preventing knife edges and avoiding boundary chipping.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The polishing process is segmented into two distinct stages with two different polishing heads: the first polishing head forms the recess at an acute angle, and the second polishing head removes chipping at the boundary with a right or obtuse angle. This segmentation allows each stage to optimize for its specific function without the trade-offs of a single unified approach.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single polishing head is used to polish the substrate, then device complexity is reduced, but manufacturing precision deteriorates due to inability to address both recess formation and boundary chipping

Engineering Contradiction:
Improvenumber of polishing headsVSAvoidpolishing boundary quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent divides the polishing function into two separate heads: the first polishing head dedicated to recess formation with acute angle polishing tools, and the second polishing head dedicated to boundary finishing with right or obtuse angle tools. This segmentation enables high manufacturing precision by addressing each polishing challenge with specialized equipment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each polishing head is optimized for its specific function with locally appropriate tool angles: the first head uses acute angles suitable for aggressive recess formation, while the second head uses right or obtuse angles suitable for precise boundary work. This local optimization achieves high overall precision despite increased device complexity.

Inventive Principle:
Principle #3Local quality

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

Effectively removes chipping by forming controlled recesses and polishing boundaries, preventing damage to laminated substrates and ensuring smooth handling.

Implementation Method 1

a first polishing head configured to press a first polishing tool having a first angle as an acute angle against a peripheral portion of a substrate to form a recess in the peripheral portion

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP4620616A1Polishing apparatus, polishing method, and polishing head
Publication Date: 2025.09.24 EBARA CORP
  • EP4620616A1 patent drawingFigure 1
  • EP4620616A1 patent drawingFigure 2
  • EP4620616A1 patent drawingFigure 3A~3B

AI summary

A polishing apparatus capable of removing a chipping is disclosed. The polishing apparatus includes a first polishing head and a second polishing head. The first polishing head is configured to press a first polishing tool against a peripheral portion of a substrate to form a recess in the peripheral portion. The second polishing head is configured to press a second polishing tool against a polishing boundary of the recess.