CMP Slurry with Polyether Amine for Dishing Reduction

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Solution Overview

Problem

Chemical mechanical polishing solutions for shallow trench isolation often result in dishing due to over-polishing of silicon nitride layers, leading to reduced planarization efficiency.

Innovation Solution

A chemical mechanical polishing solution comprising cerium oxide, polyacrylic acid, polyether amine, and water, with specific concentrations and molecular weights, is used to maintain high polishing rates of silicon dioxide while minimizing dishing, incorporating a pH regulator to optimize the polishing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If negatively charged cerium oxide is used for polishing silicon dioxide, then polishing rate is improved, but dishing formation increases due to over-polishing of silicon nitride

Engineering Contradiction:

Improvepolishing rateVSAvoiddishing amount

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Polyether amine acts as an intermediary substance that selectively adsorbs onto silicon nitride surfaces, forming a protective layer that prevents over-polishing. This mediator allows the negatively charged cerium oxide to continue polishing silicon dioxide effectively while blocking excessive material removal from silicon nitride, thus resolving the dishing problem without sacrificing polishing rate

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the chemical parameters of the polishing slurry by introducing polyether amine with specific molecular weight (1,300-750,000) and concentration (1-80 ppm). This parameter change modifies the interaction between cerium oxide particles and the wafer surface, enabling selective polishing behavior that maintains high silicon dioxide removal rate while preventing silicon nitride over-polishing

Inventive Principle:

Principle #35Parameter changes

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 effectively reduces dishing on patterned wafers while maintaining high polishing rates of silicon dioxide, improving planarization efficiency with a simple and cost-effective method.

Implementation Method 1

chemical mechanical polishing

Methodology Applied

Scientific EffectMechanical abrasion: Abrasion

Implementation Method 2

chemical mechanical polishing

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 3

negatively charged cerium oxide treated by acrylic acid

Methodology Applied

Scientific EffectElectrostatic interaction: Electrostatics

Data Source

PatentUS20230027829A1Chemical mechanical polishing solution

Publication Date: 2023.01.26 ANJI MICROELECTRONICS TECH (SHANGHAI) CO LTD

AI summary

Disclosed is a chemical mechanical polishing solution containing cerium oxide, polyacrylic acid, polyether amine and water. In this invention polyether amine can serve as an additive to reduce the dishing amount of patterned wafer by negatively charged cerium oxide, and improve the efficiency of planarization.