Reaction-Bonded Diamond-Retaining Silicon Carbide CMP Disc

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Solution Overview

Problem

Existing CMP pad conditioning discs featuring diamond particulates bonded to metal experience issues with diamond particle loss due to mechanical bond, chemical corrosion, or thermal expansion mismatch, leading to reduced effectiveness and potential damage to silicon wafers during polishing.

Innovation Solution

A ceramic substrate supporting a reaction-bonded silicon carbide layer with diamond particles, where the diamond particles are retained through a strong chemical bond formed by infiltrating a silicon carbide paste with molten silicon, creating a durable and wear-resistant RB-DSiC layer that reduces the risk of diamond particle detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If diamond particles are bonded to metal matrix mechanically, then the conditioning disc can be manufactured, but diamond particle loss occurs due to mechanical bond weakness, chemical corrosion, or thermal expansion mismatch

Engineering Contradiction:

Improvemanufacturability of conditioning discVSAvoiddiamond particle retention

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies composite materials by combining diamond particles with a reaction-bonded silicon carbide matrix. This composite structure provides both the manufacturability of a ceramic matrix and the diamond particle retention needed for reliable conditioning. The silicon carbide matrix chemically bonds to diamond particles, preventing particle loss while maintaining structural integrity during CMP operations.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the bonding mechanism parameter from mechanical bonding (in metal matrices) to chemical bonding through reaction bonding. The silicon carbide matrix forms strong chemical bonds with diamond particles during the reaction bonding process, eliminating particle loss issues associated with mechanical bonding while maintaining manufacturability through controlled thermal processing.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional metal-bonded diamond conditioning discs are used, then diamond particles can be retained initially, but particle loss occurs during polishing due to bond weakness and thermal stress

Engineering Contradiction:

Improveinitial diamond particle retentionVSAvoidservice life of conditioning disc

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent addresses thermal expansion mismatch by using a silicon carbide matrix that has thermal expansion properties compatible with diamond particles. The reaction-bonded silicon carbide matrix undergoes controlled thermal expansion during processing that matches diamond, preventing particle detachment during thermal cycling in the polishing process and extending service life.

Inventive Principle:

Principle #37Thermal expansion

Solution Approach 2:

The patent replaces the mechanical bonding system with a chemical bonding system. Instead of relying on mechanical interlocking or weak adhesive bonds in metal matrices, the silicon carbide matrix forms strong chemical bonds with diamond particles through reaction bonding, eliminating particle loss during the polishing process and extending disc durability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If diamond particles are embedded in metal matrix, then conditioning function is provided, but chemical corrosion of metal matrix leads to particle detachment

Engineering Contradiction:

Improveconditioning functionVSAvoiddiamond particle stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent creates a chemically inert environment by using a silicon carbide matrix that is resistant to chemical corrosion. The silicon carbide matrix does not corrode in the presence of CMP slurries and processing chemicals, thereby protecting the embedded diamond particles from detachment and maintaining conditioning function throughout the disc's service life.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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

The solution enhances the durability and wear resistance of CMP pad conditioning discs, preventing diamond particle loss and maintaining polishing effectiveness, thus ensuring consistent performance and reducing the risk of wafer damage during the polishing process.

Implementation Method 1

the diamond particles are retained through a strong chemical bond formed by infiltrating a silicon carbide paste with molten silicon

Methodology Applied

Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

infiltrating the SiC paste with molten silicon to form a reaction-bonded diamond-retaining silicon carbide (RB-DSiC) layer

Methodology Applied

Scientific EffectReaction bonding:

Data Source

PatentUS20240360049A1Ceramic substate with reaction-bonded silicon carbide having diamond particles

Publication Date: 2024.10.31 II VI DELAWARE INC

AI summary

A composite material can include: a substrate of a first reaction-bonded silicon carbide (first RB—SiC) material; and a reaction-bonded diamond-retaining silicon carbide (RB-DSiC) layer bonded to a surface of the substrate. In some aspects, the RB-DSiC layer includes diamond particles bonded with a second reaction-bonded silicon carbide (second RB—SiC) material. The diamond particles may be homogeneously distributed through the second RB—SiC or only at the surface thereof. The diamond particles can be in an ordered pattern or un-ordered pattern. For example, a CMP conditioning disc can include the composite material of one of the embodiments.