Microreplicated Polishing Pad Structure for CMP Co-Planarity

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Solution Overview

Problem

Chemical mechanical polishing (CMP) processes face challenges in achieving uniformity and reducing material displacement defects due to polymer aggregation and thermal expansion mismatches in microreplication techniques, leading to uneven polishing surfaces and increased conditioning time.

Innovation Solution

The development of a polishing pad with a polishing layer featuring raised cells and channels, where each cell includes a microstructured working surface, a substantially vertical channel surface, and an offset surface to accommodate polymer displacement, thereby enhancing co-planarity and reducing material displacement defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If microreplication techniques are used to create polishing surfaces, then polishing performance is improved, but polymer aggregation and thermal expansion mismatches cause material displacement defects and uneven surfaces

Engineering Contradiction:

Improvepolishing surface uniformityVSAvoidmaterial displacement defects

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The polishing pad is divided into multiple raised cells separated by channels, creating a segmented structure. Each cell acts as an independent microreplication unit with its own offset volume, isolating material displacement defects to local regions rather than affecting the entire polishing surface. This segmentation allows the majority of the surface to maintain uniformity while accommodating localized polymer aggregation and thermal expansion issues within individual cell boundaries.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The offset volume is extracted as a separate functional element within each cell, positioned between the working surface and the channel. This extracted volume specifically accommodates material displacement defects by providing a reservoir space for polymer aggregation and thermal expansion, removing these harmful effects from the polishing interface while preserving the integrity of the working surface.

Inventive Principle:

Principle #2Taking out (Extraction)

2Manufacturing precision

If conventional polishing pads are used, then manufacturing is simpler, but pad thickness uniformity is poor and conditioning time is increased

Engineering Contradiction:

Improvepad thickness uniformityVSAvoidconditioning time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The offset volume is pre-configured during pad manufacturing within each cell structure, anticipating and accommodating material displacement defects before they occur during operation. This preliminary action of creating dedicated accommodation spaces prevents future thickness variations and reduces the conditioning time required to achieve uniform polishing surfaces, as the structure is already optimized for defect management.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If polishing pads without offset volumes are used, then device complexity is reduced, but slurry consumption increases and pad life decreases

Engineering Contradiction:

Improvepad structure complexityVSAvoidslurry consumption

Core Design Contradiction:

Device complexityVSLoss of substance

Solution Approach 1:

The offset volume is implemented locally within each cell rather than as a global pad feature, concentrating the complexity only where needed for defect accommodation. This localized approach maintains simple structures in the majority of the pad while providing sophisticated defect management in specific regions, thereby reducing overall slurry consumption and extending pad life without requiring complex global structural changes.

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

This solution results in a more uniform pad thickness, reduced conditioning and break-in time, lower slurry consumption, and increased pad life, while maintaining consistent polishing performance across the substrate surface.

Implementation Method 1

thermal expansion mismatches in microreplication techniques, leading to uneven polishing surfaces

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The abrasive slurry contacts the article and removes material from the article

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS12208483B2Microreplicated polishing surface with enhanced co-planarity

Publication Date: 2025.01.28 3M INNOVATIVE PROPERTIES CO

AI summary

An article includes a polishing layer that includes a plurality of raised cells separated by a plurality of channels. Each of the plurality of raised cells includes a microstructured working surface, a substantially vertical channel surface, and an offset surface between an edge of the working surface and an upper edge of the channel surface. The microstructured working surface includes a plurality of microstructures. Tops of the plurality of microstructures define a top plane and bases of the plurality of microstructures define a base plane. The substantially vertical channel surface defines a wall of a channel of the plurality of channels and the channel surface defines a channel plane. The offset surface includes a nonplanar portion of displaced material. The displaced material defines a displacement plane that is below the base plane or within a tolerance of the top plane.