Offset Concentric Grooves for CMP Slurry Retention

Solution Overview

Problem

Conventional chemical-mechanical polishing (CMP) processes face challenges in achieving a high polishing rate while maintaining substrate planarity and low defects, often requiring excessive polishing slurry and leading to increased manufacturing costs.

Innovation Solution

A polishing pad with a unique grooving pattern featuring multiple concentric grooves having distinct centers of concentricity, where the axis of rotation is not coincident with these centers, and the grooves do not form a continuous spiral or mosaic pattern, enhancing slurry retention and polishing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If conventional grooving patterns are used on the polishing pad, then the polishing pad lifetime is improved, but the polishing rate is not adequately improved and excessive polishing slurry is required

Engineering Contradiction:

Improvepolishing pad lifetimeVSAvoidpolishing rate

Core Design Contradiction:

Duration of action of stationary objectVSProductivity

Solution Approach 1:

The polishing pad surface is segmented into multiple grooving patterns with different characteristics (radial grooves, concentric grooves, cross-hatch patterns) arranged in different zones. This segmentation allows each zone to perform specific functions: some zones retain slurry longer for polishing rate improvement, while other zones facilitate slurry distribution and debris removal for pad lifetime extension

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different grooving patterns are applied to different zones of the polishing pad surface based on local requirements. The inner zone may use a pattern optimized for slurry retention while the outer zone uses a pattern optimized for debris evacuation. This local optimization allows simultaneous improvement of polishing rate in some areas and pad lifetime in others

Inventive Principle:

Principle #3Local quality

2Device complexity

If conventional grooving patterns are used on the polishing pad, then the polishing pad structure is simple, but the polishing slurry retention is insufficient requiring larger amount of slurry

Engineering Contradiction:

Improvegrooving pattern complexityVSAvoidpolishing slurry quantity

Core Design Contradiction:

Device complexityVSQuantity of substance

Solution Approach 1:

The polishing pad surface is segmented into multiple grooving patterns with different characteristics (radial grooves, concentric grooves, cross-hatch patterns) arranged in different zones. This segmentation allows each zone to perform specific functions: some zones retain slurry longer for polishing rate improvement, while other zones facilitate slurry distribution and debris removal for pad lifetime extension

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different grooving patterns are applied to different zones of the polishing pad surface based on local requirements. The inner zone may use a pattern optimized for slurry retention while the outer zone uses a pattern optimized for debris evacuation. This local optimization allows simultaneous improvement of polishing rate in some areas and pad lifetime in others

Inventive Principle:

Principle #3Local quality

3Productivity

If polishing rate is increased to improve throughput, then the manufacturing cost is reduced, but substrate planarity and defect reduction are compromised

Engineering Contradiction:

ImprovethroughputVSAvoidsubstrate planarity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The polishing pad surface is segmented into multiple grooving patterns with different characteristics (radial grooves, concentric grooves, cross-hatch patterns) arranged in different zones. This segmentation allows each zone to perform specific functions: some zones retain slurry longer for polishing rate improvement, while other zones facilitate slurry distribution and debris removal for pad lifetime extension

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different grooving patterns are applied to different zones of the polishing pad surface based on local requirements. The inner zone may use a pattern optimized for slurry retention while the outer zone uses a pattern optimized for debris evacuation. This local optimization allows simultaneous improvement of polishing rate in some areas and pad lifetime in others

Inventive Principle:

Principle #3Local quality

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 improves polishing rate and substrate planarity, reduces defects, and optimizes slurry usage, thereby enhancing the cost-effectiveness and efficiency of the CMP process.

Implementation Method 1

The polishing composition typically contains one or more chemicals that interact with or dissolve portions of the uppermost wafer layer(s)

Methodology Applied

Scientific EffectChemical interaction and dissolution: Solvation

Implementation Method 2

one or more abrasive materials that physically remove portions of the layer(s)

Methodology Applied

Scientific EffectPhysical abrasion: Abrasion

Implementation Method 3

distribution of applied pressure across a substrate to be polished

Methodology Applied

Scientific EffectPressure distribution: Pressure Gradient

Data Source

PatentUS9687956B2Polishing pad with offset concentric grooving pattern and method for polishing a substrate therewith

Publication Date: 2017.06.27 CMC MATERIALS INC

AI summary

The invention provides a polishing pad and a method of using the polishing pad for chemically-mechanically polishing a substrate. The polishing pad comprises a plurality of grooves composed of at least a first plurality of concentric grooves having a first center of concentricity, and a second plurality of concentric grooves having a second center of concentricity. The first center of concentricity is not coincident with the second center of concentricity, the axis of rotation of the polishing pad is not coincident with at least one of the first center of concentricity and the second center of concentricity, the plurality of grooves does not consist of a continuous spiral groove, and the polishing surface does not comprise a mosaic groove pattern.