CMP Pad Pattern Substrate for Uniform Polishing

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Solution Overview

Problem

Conventional chemical mechanical polishing pads face challenges in maintaining uniform polishing performance and followability with the wafer surface due to irregularities in protrusions and grooves, which are difficult to control and adjust for specific polishing conditions, leading to inconsistent results and reduced efficiency.

Innovation Solution

A chemical mechanical polishing pad with a pattern structure featuring figure units that have a predetermined contact area ratio and circumferential length per unit area, allowing for controlled surface topography and improved liquid distribution, enabling uniform polishing performance and increased efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conditioning is continuously performed during polishing to maintain uniform polishing performance, then polishing performance uniformity is improved, but device complexity and operational complexity increase

Engineering Contradiction:

Improvepolishing performance uniformityVSAvoidconditioning process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-forming the protrusion pattern structure on the polishing pad before polishing begins. The pattern substrate is embedded in the pad material during manufacturing, creating predetermined protrusions with specific geometries, densities, and distributions. This eliminates the need for continuous conditioning during polishing, as the topography is already optimized for uniform polishing performance from the start.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If conditioning process variables (diamond size, density, rotational speed, pressure) are adjusted to control protrusion shape and size, then surface topography control is improved, but manufacturing complexity and process control difficulty increase

Engineering Contradiction:

Improvesurface topography controlVSAvoidconditioning process control

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The desired surface topography is pre-established by embedding a pattern substrate with predetermined protrusion patterns into the polishing pad during manufacturing. This eliminates the need for complex conditioning processes to create the topography, as the protrusions are already formed with precise geometries, sizes, and distributions before the pad is put into service.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical conditioning process (using diamond particles to scratch and shape the pad surface) with a direct embedding approach. Instead of using mechanical forces and abrasive wear to create the topography, the pattern substrate is integrated into the pad material, transferring the protrusion pattern directly during pad fabrication. This substitution eliminates the complexity of controlling multiple conditioning variables.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If conventional conditioning is used to form protrusions, then polishing pad topography is created, but it is difficult to adjust shape and size for specific polishing conditions

Engineering Contradiction:

Improvepolishing condition adaptabilityVSAvoidprotrusion shape and size control

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating a pattern substrate with spatially varying protrusion characteristics. Different regions of the substrate can have protrusions with different geometries, sizes, densities, and distributions, allowing the polishing pad to provide locally optimized topography for specific polishing conditions. This enables adaptation to different polishing requirements across different areas of the wafer or for different material types.

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 pad maintains consistent polishing performance by optimizing the contact area and liquid distribution, improving followability with the wafer surface and enhancing the overall efficiency of the polishing process.

Implementation Method 1

The chemical mechanical polishing (CMP) process is a process for processing a substrate (wafer, etc.) to be processed while applying pressure and rotation to the surface of a pad, which is a rotating counterpart, and for polishing the surface of the substrate

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 2

Among these grooves and protrusions, the grooves serve as a supply path for the polishing liquid

Methodology Applied

Scientific EffectFluid flow through grooves:

Data Source

PatentUS20220134507A1Chemical mechanical polishing pad having pattern substrate

Publication Date: 2022.05.05 KOREA INSTITUTE OF INDUSTRIAL TECHNOLOGY

AI summary

The present invention relates to a chemical mechanical polishing pad having a pattern structure. The configuration of the present invention provides a chemical mechanical polishing pad having a pattern structure including a polishing pad configured to polish a wafer placed thereon; and a plurality of figure units formed on the polishing pad and formed to protrude from an upper portion of the polishing pad. The figure units are formed to have a predetermined contact area ratio and a predetermined circumferential length per unit area which correspond to a target polishing characteristic.