Magnetically Coupled Pad Conditioning Disk for CMP

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Solution Overview

Problem

Conventional chemical mechanical polishing (CMP) apparatuses face issues with mechanical fasteners used to attach pad conditioning disks, which can loosen during operation, leading to degradation of the pad surface, increased tool downtime, and risk of rust-induced scratching of wafers.

Innovation Solution

The use of a magnetically coupled pad conditioning disk eliminates the need for mechanical fasteners by employing an electromagnet in the conditioning head and a ferromagnetic material in the pad conditioning disk, ensuring secure attachment and easy removal without excessive force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical fasteners are used to attach the pad conditioning disk, then the disk can be securely held during operation, but the fasteners can loosen over time causing pad surface degradation and requiring tool downtime for maintenance

Engineering Contradiction:

Improveattachment reliabilityVSAvoidtool downtime

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical fastener system with a magnetic field-based attachment system. An electromagnet in the conditioning head generates a magnetic field that attracts ferromagnetic material embedded in the pad conditioning disk, providing secure attachment without mechanical fasteners. This eliminates the loosening problem and reduces maintenance downtime while maintaining reliable attachment during operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If mechanical fasteners are used to attach the pad conditioning disk, then the disk can be securely held during operation, but the fasteners are susceptible to rust and corrosion causing scratching of wafer surfaces

Engineering Contradiction:

Improveattachment reliabilityVSAvoidrust-induced scratching

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent eliminates mechanical fasteners that are susceptible to rust and corrosion by using a magnetic field-based attachment system. The electromagnet and ferromagnetic material provide secure attachment without contact between metal fasteners and the pad conditioning disk, preventing rust-induced scratching of wafer surfaces while maintaining reliable attachment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If magnetic coupling is used to attach the pad conditioning disk, then mechanical fasteners are eliminated preventing rust and loosening, but the electromagnetic system requires energy consumption

Engineering Contradiction:

Improveattachment reliabilityVSAvoidelectromagnet energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The electromagnet operates periodically rather than continuously - it is energized only during pad conditioning operations when the disk needs to be attached, and de-energized during other operations. This periodic activation maintains reliable attachment when needed while significantly reducing overall energy consumption compared to continuous operation.

Inventive Principle:

Principle #19Periodic action

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 reduces tool downtime, increases the availability of the CMP apparatus, and prevents rust-related scratching of wafer surfaces by maintaining a secure and rust-free attachment of the pad conditioning disk.

Implementation Method 1

the conditioning head (32) comprises an electromagnet (328, 338) and the pad conditioning disk (30) comprises a first ferromagnetic material portion (308) configured to be attracted to the electromagnet (328, 338) when the electromagnet (328, 338) is energized

Methodology Applied

Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentUS12151336B2Chemical mechanical polishing apparatus using a magnetically coupled pad conditioning disk

Publication Date: 2024.11.26 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A chemical mechanical polishing (CMP) apparatus includes a polishing pad located on a top surface of a platen configured to rotate around a vertical axis passing through the platen, a wafer carrier configured to hold a substrate on a bottom surface thereof and to press the substrate on a top surface of the polishing pad, a slurry dispenser configured to dispense slurry over the top surface of the polishing pad, and a pad conditioning unit comprising a pad conditioning disk and a conditioning head configured to hold the pad conditioning disk. The conditioning head includes an electromagnet and the pad conditioning disk comprises a first ferromagnetic material portion configured to be attracted to the electromagnet when the electromagnet is energized.