CMP Slurry Composition for Corrosion-Controlled Metal Removal

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Solution Overview

Problem

Chemical mechanical polishing (CMP) processes face challenges in efficiently removing conductive materials from semiconductor workpieces while minimizing metal corrosion and ion re-deposition, which can lead to defects such as dishing and metal particles remaining on the surface.

Innovation Solution

A CMP slurry is developed containing abrasives, surfactants, solvents, chelator additives, inhibitor additives, and reactant additives, with a chelator to inhibitor ratio adjusted based on the electrical potential of the conductive material to optimize removal rates and prevent corrosion, using a combination of mechanical and chemical forces to remove conductive material without redepositing metal ions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a CMP slurry is used to remove conductive material, then the removal rate is improved, but metal corrosion and ion re-deposition occur causing defects

Engineering Contradiction:

Improveremoval rateVSAvoidmetal corrosion and ion re-deposition

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent adjusts the pH value of the CMP slurry to specific ranges (e.g., pH 7-9 for copper, pH 9-11 for cobalt) to optimize the balance between removal rate and corrosion prevention. This parameter change allows the slurry to effectively remove conductive material while minimizing metal corrosion and ion re-deposition defects

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces chelating agents as intermediary substances that form stable complexes with metal ions, preventing them from re-depositing on the workpiece surface. These chelating agents act as mediators between the abrasive particles and metal ions, controlling the chemical reactions to reduce harmful effects while maintaining effective material removal

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the chelator to inhibitor ratio is not optimized, then corrosion protection is improved, but removal rate decreases

Engineering Contradiction:

Improvecorrosion protectionVSAvoidremoval rate

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent optimizes the chelator to inhibitor ratio as a critical parameter to achieve the desired balance. By adjusting this ratio according to the specific conductive material being processed, the slurry formulation maximizes both corrosion protection and removal rate, preventing the trade-off from limiting productivity

Inventive Principle:

Principle #35Parameter changes

3Productivity

If mechanical grinding is used to remove excess conductive material, then removal efficiency is improved, but surface defects like dishing occur

Engineering Contradiction:

Improveremoval efficiencyVSAvoidsurface flatness

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs a composite CMP slurry system combining abrasive particles, chelating agents, corrosion inhibitors, and pH buffers in specific proportions. This composite formulation works synergistically with the mechanical grinding action to achieve high removal efficiency while the chemical components prevent surface defects like dishing by controlling material removal uniformity and preventing ion re-deposition

Inventive Principle:

Principle #40Composite materials

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 CMP slurry effectively removes conductive material with minimized metal corrosion and ion re-deposition, ensuring higher yields and reducing defects like dishing, by balancing the chelator to inhibitor ratio and using reactant additives to soften the material for easier removal.

Implementation Method 1

chelator additives, inhibitor additives, and reactant additives, with a chelator to inhibitor ratio adjusted based on the electrical potential of the conductive material

Methodology Applied

Scientific EffectChelation:

Implementation Method 2

chelator additives, inhibitor additives, and reactant additives

Methodology Applied

Scientific EffectCorrosion inhibition:

Implementation Method 3

reactant additives to soften the material for easier removal

Methodology Applied

Scientific EffectChemical reaction:

Implementation Method 4

the excess conductive material of a surface of the workpiece may be contacted to a polishing pad, and the two may be rotated in order to grind excess conductive material away

Methodology Applied

Scientific EffectMechanical grinding: Abrasion

Data Source

PatentUS20240395562A1Chemical mechanical polish slurry and method of manufacture

Publication Date: 2024.11.28 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Methods of manufacturing a chemical-mechanical polishing (CMP) slurry and methods of performing CMP process on a substrate comprising metal features are described herein. The CMP slurry may be manufactured using a balanced concentration ratio of chelator additives to inhibitor additives, the ratio being determined based on an electro potential (Ev) value of a metal material of the substrate. The CMP process may be performed on the substrate based on the balanced concentration ratio of chelator additives to inhibitor additives of the CMP slurry.