High-Purity Removal Rate Enhancer Conductivity for Slurry LPC Reduction

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Solution Overview

Problem

The semiconductor industry faces challenges in minimizing large particle counts (LPCs) in copper slurries used for chemical mechanical polishing, which can lead to defects and scratches during chip fabrication, particularly due to the contribution of removal rate enhancers (RREs) and other chemicals, despite existing filtration methods.

Innovation Solution

Selecting high-purity removal rate enhancers (RREs) based on their conductivity in deionized water, which adheres to a specific inequality (C≤a*W+b), where C is the conductivity and W is the weight percentage, to minimize LPCs in the slurry, and using these RREs in combination with abrasives and corrosion inhibitors to create a polishing composition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If filtration methods are used to remove particles from copper slurry, then large particle counts are reduced, but removal rate of copper may be compromised

Engineering Contradiction:

Improvelarge particle count reductionVSAvoidcopper removal rate

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the chemical composition parameters of the slurry by introducing specific organic acids (formic acid, acetic acid, propionic acid, or butyric acid) and their salts at controlled concentrations (0.1-10% by weight). This chemical modification allows the slurry to maintain low large particle counts while preserving copper removal rate, resolving the contradiction between particle reduction and productivity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses organic acids and their salts as intermediary substances that mediate between the abrasive particles and copper surface. These intermediaries modify the chemical environment to prevent particle aggregation and maintain dispersion, enabling both low LPCs and high removal rates simultaneously

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If high concentration slurry is used to enhance removal rate, then productivity increases, but large particle counts increase leading to more defects

Engineering Contradiction:

Improveremoval rateVSAvoiddefect rate

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent modifies the chemical parameters by adding organic acids that change the pH and chemical environment of the slurry. This allows high concentration slurries to maintain particle dispersion and low LPCs even at elevated concentrations, enabling high removal rates without increased defect rates

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite slurry system combining abrasives with specific organic acids and their salts. This composite formulation achieves synergistic effects where the organic acid component prevents particle aggregation while the abrasive component maintains high removal rate, resolving the contradiction between productivity and precision

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

This approach significantly reduces LPCs in copper slurries, ensuring lower defect rates and improved wafer quality by correlating conductivity with LPC contributions, allowing for more precise purity control and reduced risk of deep scratches during CMP processes.

Implementation Method 1

The RRE can be an amino acid or derivative thereof... selecting high-purity removal rate enhancers (RREs) based on their conductivity in deionized water

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

based on their conductivity in deionized water, which adheres to a specific inequality (C≤a*W+b), where C is the conductivity and W is the weight percentage

Methodology Applied

Scientific EffectElectrical Conductivity: Conduction (electrical)

Implementation Method 3

The process known as chemical mechanical polishing or planarization (CMP) involves the planarization of different layers on semiconductor wafers using a polishing pad and slurry to polish away excess or unwanted layers

Methodology Applied

Scientific EffectChemical Mechanical Polishing:

Data Source

PatentUS10167415B2Reduction in large particle counts in polishing slurries

Publication Date: 2019.01.01 FUJIFILM ELECTRONIC MATERIALS U S A INC

AI summary

The present disclosure provides a method for reducing large particle counts (LPCs) in copper chemical mechanical polishing slurry by way of using high purity removal rate enhancer (RRE) in the slurry. The conductivity of the RRE in deionized water solutions correlates very strongly with the number of LPCs in the RRE, and thus in a slurry using the RRE.