Segmented Porous CMP Pad for Wafer Edge Uniformity

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Solution Overview

Problem

The challenges in semiconductor fabrication include long-range deformation of polishing pads during chemical-mechanical polishing (CMP) processes, leading to non-uniformity and defects at the wafer edge, particularly for larger wafers, and the need for longer break-in cycles with non-porous pads.

Innovation Solution

The introduction of a polishing pad with discrete segments and controlled porosity to minimize long-range deformation, combined with specific groove designs and material selection, ensures uniform material removal and improved edge control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a non-porous polishing pad is used, then the pad structure is simple and easy to manufacture, but the pad experiences long-range deformation leading to non-uniformity and defects at the wafer edge

Engineering Contradiction:

Improvewafer edge uniformityVSAvoidpolishing pad structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The polishing pad is divided into multiple discrete porous segments arranged in an array pattern, with each segment being independently porous while the overall structure remains controlled. This segmentation prevents long-range deformation from spreading across the entire pad, thereby improving wafer edge uniformity while maintaining a manageable structural complexity through modular design

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The polishing pad structure transitions from uniform non-porous to having localized porous regions distributed across the pad surface. Each local segment provides controlled deformation characteristics, allowing the pad to maintain simplicity in individual segment design while achieving improved overall uniformity through the distributed porous architecture

Inventive Principle:

Principle #3Local quality

2Loss of time

If a non-porous polishing pad is used, then the manufacturing process is simpler, but the break-in cycle is longer

Engineering Contradiction:

Improvebreak-in cycle durationVSAvoidpolishing pad manufacturing

Core Design Contradiction:

Loss of timeVSEase of manufacture

Solution Approach 1:

The porous structure is pre-formed in the polishing pad segments during manufacturing, creating the necessary deformation characteristics before the pad is put into service. This preliminary structuring eliminates the need for extended break-in cycles, reducing time loss while the porous formation process integrates into the existing manufacturing workflow without significantly complicating production

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If discrete porous segments are introduced to minimize deformation, then within-wafer uniformity is enhanced, but the polishing pad structure becomes more complex

Engineering Contradiction:

Improvewithin-wafer uniformityVSAvoidpolishing pad structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple discrete porous segments are arranged and combined in a systematic array pattern to form the complete polishing pad structure. The segments work together collectively to achieve enhanced within-wafer uniformity, while the regular repeating pattern allows the complex structure to be managed through standardized modular units rather than unique complex components

Inventive Principle:

Principle #5Merging (Combining)

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 enhances within-wafer and within-zone uniformity, reduces defects, and stabilizes the polishing process, allowing for efficient planarization across the wafer surface.

Implementation Method 1

a polishing pad with discrete segments and controlled porosity to minimize long-range deformation

Methodology Applied

Scientific EffectPorosity: Porosity

Implementation Method 2

chemical-mechanical polishing (CMP) process which is often used to selectively remove high elevation features by a combination of mechanical polishing and chemical reaction

Methodology Applied

Scientific EffectChemical reaction:

Data Source

PatentUS20250316489A1Semiconductor device fabrication methods and devices for forming the same

Publication Date: 2025.10.09 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A chemical mechanical polishing device is provided. The chemical mechanical polishing device includes a porous polishing pad in which a plurality of pores is formed and a plurality of discrete segments at one side thereof. The segments have a maximum width Sd no larger than a predetermined value, for example, 5 mm, to prevent from laterally spreading a deformation caused by a downward force applied thereto.