CMP Polishing Pad Grooves Orthogonal Trajectory Slurry Retention

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Solution Overview

Problem

Conventional chemical mechanical polishing (CMP) pads with various groove patterns face inefficiencies in slurry retention due to centripetal force, leading to excessive slurry outflow and poor polishing performance.

Innovation Solution

A CMP pad design featuring grooves shaped according to an orthogonal trajectory equation (r*=rO⁢ⅇ12⁢(3⁢⁢θ)3/2) to impede slurry migration, increasing retention time and reducing slurry consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If conventional groove patterns are used on polishing pads, then slurry can be supplied to the polishing interface, but slurry outflow increases due to centripetal force during pad rotation

Engineering Contradiction:

Improveslurry consumptionVSAvoidpolishing performance

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The groove orientation parameter is changed from conventional radial or concentric patterns to a specific angular range (30-60 degrees relative to the radial direction). This parameter modification optimizes slurry retention by reducing outward migration while maintaining adequate slurry supply to the polishing interface, directly addressing the contradiction between slurry consumption and polishing performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The groove pattern is designed with varying local characteristics - grooves are positioned at specific angular orientations in different radial zones of the polishing pad. This local differentiation allows the pad to retain slurry effectively in the wafer contact zone while still permitting slurry supply, resolving the conflict between preventing slurry loss and maintaining polishing quality

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If radial grooves are used to channel slurry off the pad, then slurry flow is enhanced, but excessive heating occurs at the polishing interface

Engineering Contradiction:

Improveslurry flowVSAvoidinterface temperature

Core Design Contradiction:

Quantity of substanceVSTemperature

Solution Approach 1:

The groove orientation is set asymmetrically at 30-60 degrees relative to the radial direction, rather than using symmetric radial or concentric patterns. This asymmetric configuration creates a balance where grooves provide adequate slurry transport pathways without creating direct channels that would cause excessive slurry ejection and subsequent interface heating

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The groove pattern provides partial slurry channeling rather than complete radial evacuation. By orienting grooves at moderate angles, the design allows enough slurry to reach the polishing interface for effective polishing while preventing excessive slurry flow that would lead to heating problems

Inventive Principle:

Principle #16Partial or excessive 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

The design effectively reduces slurry consumption and operating costs by enhancing slurry retention on the polishing pad, improving polishing performance and pad longevity.

Implementation Method 1

the migration of dispensed slurry under the centripetal force actuated by the rotating polisher

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

the orthogonal portion having a length and being shaped along the entire length to be orthogonal to the ideal fluid trajectory along the orthogonal portion

Methodology Applied

Scientific EffectFluid flow resistance: Drag

Data Source

PatentUS7311590B1Polishing pad with grooves to retain slurry on the pad texture

Publication Date: 2007.12.25 DUPONT ELECTRONIC MATERIALS HLDG INC

AI summary

A rotational chemical mechanical polishing pad designed for use with a polishing medium. The polishing pad includes a polishing layer having a polishing surface containing a plurality of grooves. At least a portion of each of the plurality of grooves has a shape and orientation determined as a function of the trajectory of the polishing medium during use of the pad.