CMP Slurry Additives for Hardened Fluid Planarization

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Solution Overview

Problem

Conventional Chemical Mechanical Polishing (CMP) processes are ineffective for softer materials like photoresist and anti-reflective coating materials, often causing scratching and peeling due to their mechanical grinding nature, which is not suited for these materials.

Innovation Solution

A tuned CMP process using a slurry solution with additives such as oxidizers, non-spherical abrasives, and stripper components like N-methyl-2-pyrrolidone, hydrogen peroxide, and sulfuric acid to break down and soften the surface of hardened fluid materials, reducing friction and peeling, and incorporating a CMP system with a polishing pad and vacuum-secured wafer setup.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional CMP process with mechanical grinding is used, then harder materials like dielectric material can be effectively planarized, but softer materials like photoresist and anti-reflective coating materials suffer from scratching and peeling

Engineering Contradiction:

Improveplanarization qualityVSAvoidscratching and peeling

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the CMP slurry by incorporating oxidizers (hydrogen peroxide, ammonium persulfate), strippers (NMP, DMSO, DMF), and chelating agents (EDTA, citric acid) to alter the interaction mechanism between slurry and softer materials, preventing mechanical damage while maintaining planarization capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent reduces reliance on mechanical grinding by enhancing chemical action through oxidizers that soften the material surface and strippers that facilitate material removal, thereby substituting pure mechanical force with a combined chemical-mechanical approach suitable for softer materials

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If slurry solution with high viscosity is used to hold very small particles, then particle suspension is improved, but flow and distribution characteristics may be affected

Engineering Contradiction:

Improveparticle suspension stabilityVSAvoidslurry flow and distribution

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent adjusts the viscosity parameter of the slurry solution to an optimal range that balances particle suspension stability with adequate flow characteristics, ensuring both small particles remain suspended and the slurry distributes evenly during CMP processing

Inventive Principle:

Principle #35Parameter changes

3Reliability

If oxidizers and strippers are added to slurry solution, then effectiveness on softer materials is improved, but slurry composition complexity increases

Engineering Contradiction:

ImproveCMP process effectiveness on softer materialsVSAvoidslurry composition complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a composite slurry formulation integrating multiple functional components (oxidizers, strippers, chelating agents, abrasives) that work synergistically to enhance CMP effectiveness on softer materials while managing the complexity through coordinated formulation

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 tuned CMP process effectively planarizes the surface of hardened fluid materials without damaging the substrate, ensuring even feature heights and preventing scratching, thereby improving the surface quality for subsequent layers.

Implementation Method 1

the solution comprising an oxidizer and a stripper additive

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

a tuned CMP process using a slurry solution with additives such as oxidizers, non-spherical abrasives, and stripper components like N-methyl-2-pyrrolidone, hydrogen peroxide, and sulfuric acid to break down and soften the surface

Methodology Applied

Scientific EffectSolvation: Solvation

Implementation Method 3

The particles help grind away and smooth the surface of the substrate

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 4

polishing the surface of the hardened fluid material with a polishing head

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS11312882B2CMP slurry solution for hardened fluid material

Publication Date: 2022.04.26 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A slurry solution for a Chemical Mechanical Polishing (CMP) process includes a wetting agent, a stripper additive that comprises at least one of: N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), sulfolane, and dimethylformamide (DMF), and an oxidizer additive comprising at least one of: hydrogen peroxide (H2O2), ammonium persulfate ((NH4)2S2O8), peroxymonosulfuric acid (H2SO5), ozone (O3) in de-ionized water, and sulfuric acid (H2SO4).