CMP Polishing Pad Microtexture Grinding via Porous Abrasive

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for manufacturing chemical mechanical polishing pads lack the capability to achieve a consistent pad surface microtexture, leading to inconsistent material removal and increased defectivity in substrates during chemical mechanical planarization processes.

Innovation Solution

The method involves grinding the surface of a polyurethane or polyurethane foam CMP polishing layer with a rotary grinder having a porous abrasive material, held in place on a flat platen, to create a consistent microtexture with a surface roughness of 0.01 μm to 25 μm, Sq, which enhances polishing efficiency and extends pad life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional methods (skiving, injection molding, buffing) are used to shape polishing pads, then manufacturing is simpler and faster, but the pad surface microtexture is inconsistent leading to high defectivity

Engineering Contradiction:

Improvepad surface microtexture consistencyVSAvoidgrinding process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The pad surface is pre-conditioned during manufacturing by grinding with a porous abrasive material, creating the desired microtexture before the pad is used for polishing. This preliminary action eliminates the need for break-in periods and ensures consistent microtexture from the start, resolving the contradiction between manufacturing simplicity and surface consistency.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If buffing methods are used to smooth pad surfaces, then planarization capability is improved, but so much material is removed that pad useful life is adversely affected

Engineering Contradiction:

Improvesurface smoothnessVSAvoidpad useful life

Core Design Contradiction:

Manufacturing precisionVSDuration of action of moving object

Solution Approach 1:

A porous abrasive material is used for grinding the pad surface, which allows controlled material removal to create microtexture without excessive material loss. The porous structure enables efficient cutting action while maintaining pad thickness and extending useful life, resolving the contradiction between surface smoothness and pad durability.

Inventive Principle:

Principle #31Porous materials

3Manufacturing precision

If single point facing techniques are used to shape pads, then manufacturing is straightforward, but tooling wear and positioning inaccuracy prevent consistent microtexture

Engineering Contradiction:

Improvepad surface microtexture consistencyVSAvoidtooling wear resistance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The porous abrasive material on the grinding wheel self-sharpenes during operation, maintaining its cutting capability without requiring frequent tool replacement or reconditioning. This self-service property eliminates tooling wear issues and positioning inaccuracies, ensuring consistent microtexture throughout the manufacturing process.

Inventive Principle:

Principle #25Self-service

4Productivity

If injection molding is used to manufacture pads, then production is efficient, but material flow inconsistency causes non-uniform pad surfaces

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidpad surface uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The grinding process is applied as a preliminary action after injection molding to correct surface non-uniformities. This two-step approach maintains the productivity benefits of injection molding while achieving the surface uniformity required for low defectivity, resolving the contradiction between manufacturing efficiency and surface precision.

Inventive Principle:

Principle #10Preliminary action

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 results in pre-conditioned polishing pads with improved uniformity and reduced defectivity, enabling enhanced polishing performance and extended pad life by maintaining the original surface topography and minimizing material removal.

Implementation Method 1

grinding the surface of a polymeric, preferably, polyurethane or polyurethane foam, CMP polishing layer... with a rotary grinder... made of a porous abrasive material

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 2

held in place on a flat platen surface, such as by vacuum or a pressure sensitive adhesive

Methodology Applied

Scientific EffectVacuum: Vacuum

Data Source

PatentUS9802293B1Method to shape the surface of chemical mechanical polishing pads

Publication Date: 2017.10.31 DUPONT ELECTRONIC MATERIALS HLDG INC

AI summary

The present invention provides methods for making a pre-conditioned chemical mechanical (CMP) polishing pad having a pad surface microtexture effective for polishing comprising grinding the surface of the CMP polishing pad having a radius with a rotary grinder while it is held in place on a flat bed platen surface, the rotary grinder having a grinding surface disposed parallel to or substantially parallel to the surface of the flat bed platen and made of a porous abrasive material, wherein the resulting CMP polishing pad has a surface roughness of from 0.01 μm to 25 μm, Sq. The present invention also provides a CMP polishing pad having a series of visibly intersecting arcs on the polishing layer surface, the intersecting arcs having a radius of curvature equal to or greater than half of the radius of curvature of the pad and extending all the way around the surface of the pad in radial symmetry around the center point of the pad.