Polishing Pad Conditioning with Feedback Wear Compensation

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Solution Overview

Problem

Conventional chemical mechanical polishing (CMP) processes face issues with uneven polishing surfaces due to pad wear, leading to inconsistent wafer processing and potential defects in semiconductor manufacturing.

Innovation Solution

A closed-loop control system measures the polishing pad's surface profile and adjusts conditioning parameters, such as downforce and sweeping speed, to maintain a desired reference profile, ensuring consistent pad wear and uniform planarization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional CMP operation is performed, then wafer planarization is achieved, but the polishing pad surface becomes uneven during processing

Engineering Contradiction:

Improvewafer planarization qualityVSAvoidpolishing pad surface uniformity

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The system performs preliminary measurement of the polishing pad surface profile before CMP processing, and pre-adjusts the conditioner downforce distribution to compensate for anticipated pad wear patterns. This proactive approach prevents surface nonplanarity from developing during wafer processing, maintaining consistent polishing quality throughout the pad's operational life.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the polishing pad surface profile during and between CMP operations, comparing measured data against target specifications. Based on this feedback, the controller dynamically adjusts conditioner downforce and other parameters to correct deviations, ensuring the pad maintains uniform surface characteristics and consistent wafer planarization quality.

Inventive Principle:

Principle #23Feedback

2Productivity

If polishing pad is used for extended processing, then productivity increases, but surface nonplanarity develops

Engineering Contradiction:

Improvewafer processing throughputVSAvoidsurface planarity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system implements periodic conditioning cycles during wafer processing, where the conditioner is activated at regular intervals to refresh the polishing pad surface. This periodic intervention removes accumulated nonplanarity and debris, restoring uniform polishing performance without requiring pad replacement, thereby maintaining both high productivity and surface quality throughout extended processing periods.

Inventive Principle:

Principle #19Periodic action

3Stability of the object's composition

If conditioner downforce is increased to maintain pad uniformity, then pad surface quality improves, but wafer processing time increases

Engineering Contradiction:

Improvepolishing pad surface uniformityVSAvoidwafer processing cycle time

Core Design Contradiction:

Stability of the object's compositionVSLoss of time

Solution Approach 1:

The system applies conditioner downforce non-uniformly across the polishing pad surface, concentrating higher downforce in regions where measurement indicates greater nonplanarity or wear. This localized conditioning approach maintains pad uniformity where needed while minimizing unnecessary conditioning in already-uniform areas, reducing overall processing time without sacrificing surface quality.

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 system effectively maintains polishing pad uniformity, enhancing the quality and consistency of wafer processing by minimizing surface irregularities and improving planarity.

Implementation Method 1

A surface of the polishing pad is contacted with a conditioner... sweeping the conditioner across a surface of the polishing pad

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS12528154B2Method for conditioning polishing pad

Publication Date: 2026.01.20 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method includes measuring a first thickness at a first location of the polishing pad and a second thickness at a second location of the polishing pad; obtaining a first reference thickness at the first location of the polishing pad, wherein the first reference thickness is an average thickness of multiple thicknesses at the first location; obtaining a second reference thickness at the second location of the polishing pad, wherein the second reference thickness is an average thickness of multiple thicknesses at the second location; calculating a first thickness difference; calculating a second thickness difference; modifying a conditioning parameter value at the first location of the polishing pad; and sweeping a conditioner across a surface of the polishing pad; and applying a downforce or a sweeping speed to the conditioner that urges the conditioner against the first location of the polishing pad according to the modified conditioning parameter value.