Copper CMP Slurry with Co-Inhibitor for Dishing Control

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Solution Overview

Problem

Current chemical mechanical polishing compositions for copper conductors face challenges in achieving a high removal rate while preventing metal dishing and erosion, requiring multiple composition changes for different stages of polishing and resulting in increased waste and process complexity.

Innovation Solution

A chemical mechanical polishing composition comprising polishing abrasive, an oxidizing agent, an accelerating compound, an inhibitor, and a co-inhibitor, which maintains a high removal rate while inhibiting static etch rate, allowing for a single composition to be used across both bulk and fine polishing stages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If higher rate of polishing is used to increase yield per unit time, then productivity is improved, but metal dishing and erosion are accelerated

Engineering Contradiction:
Improveyield per unit timeVSAvoidmetal dishing and erosion
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical composition parameters of the polishing slurry by introducing a co-inhibitor that specifically controls the etching rate. This allows the polishing process to maintain high removal rates while preventing excessive etching that causes dishing and erosion, thus resolving the contradiction between productivity and quality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The polishing composition uses a composite chemical system combining multiple inhibitors (traditional inhibitor plus co-inhibitor) with specific abrasive particles and chelating agents. This composite formulation enables simultaneous optimization of removal rate and surface quality control, addressing the trade-off between high productivity and minimizing harmful effects.

Inventive Principle:
Principle #40Composite materials

2Productivity

If inferior uniformity is used to reduce polishing time, then productivity is improved, but metal dishing and erosion become more serious

Engineering Contradiction:
Improvepolishing timeVSAvoidmetal dishing and erosion
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent adjusts the chemical parameters of the polishing slurry by adding a co-inhibitor that specifically targets and controls etching uniformity. This modification allows the process to achieve better uniformity without significantly extending polishing time, thus resolving the contradiction between productivity and quality.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If two stages of polishing process are used to prevent metal dishing and erosion, then manufacturing precision is improved, but device complexity and loss of substance increase

Engineering Contradiction:
Improvecontrol of metal dishing and erosionVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent creates a universal polishing composition that can handle both bulk copper removal and fine-tuning of surface quality in a single formulation. The co-inhibitor enables the slurry to perform dual functions: maintaining high removal rate for productivity while simultaneously controlling etching for precision, thus eliminating the need for composition changes between stages.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functions of two separate polishing compositions into one unified formulation by combining the roles of traditional inhibitors with the newly introduced co-inhibitor. This single composition performs both bulk removal and precision control functions that previously required separate stages, reducing process complexity and material waste.

Inventive Principle:
Principle #5Merging (Combining)

4Manufacturing precision

If two stages of polishing process are used to prevent metal dishing and erosion, then manufacturing precision is improved, but loss of substance increases

Engineering Contradiction:
Improvecontrol of metal dishing and erosionVSAvoidwaste material
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The universal polishing composition with co-inhibitor serves multiple functions simultaneously, allowing a single slurry formulation to be used throughout the entire polishing process. This eliminates the need to discard and replace compositions between stages, thereby reducing waste material while maintaining precision control.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 composition effectively reduces metal dishing and erosion, maintains a high removal rate, and simplifies the polishing process by eliminating the need for multiple composition changes, thereby improving yield and reducing waste.

Implementation Method 1

a chemical mechanical polishing composition comprising polishing abrasive, an oxidizing agent, an accelerating compound, an inhibitor, and a co-inhibitor

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

The chemical mechanical polishing mainly is to remove metal by polishing transversely; it works only when the mechanical and the chemical actions are used simultaneously

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentUS7931714B2Composition useful to chemical mechanical planarization of metal
Publication Date: 2011.04.26 VIBRANTZ CORP

AI summary

A chemical mechanical polishing composition, the polishing composition includes polishing abrasive, an oxidizing agent, an accelerating compound, an inhibitor, a co-inhibitor, and a solvent as the remaining. The composition can maintain a high removal rate through polishing, meantime it has a feature to inhibit static etch rate and lower the defect of polishing including metal dishing and erosion. Hence it needs no change of the composition for simultaneously removing a most part of a metal layer, particularly for a first stage of polishing bulk copper layer and for a second micro-polishing stage of removing the remaining less copper; the present invention has the advantage of simplifying processing and reducing waste.