CMP Polishing Pad with Segmented Foundation and Soft Surface Layer

Solution Overview

Problem

Conventional chemical mechanical polishing (CMP) pads face performance trade-offs between across-wafer uniformity and within-die planarization, with hard pads causing scratches and soft pads leading to dishing, and existing approaches limit the decoupling of polishing surface and bulk properties, compromising defect characteristics and planarization performance.

Innovation Solution

The development of polishing pads with a foundation layer and a polishing surface layer, where the foundation layer provides support and the surface layer is softer, allowing for decoupling of material properties to optimize both planarization performance and defect characteristics, with the surface layer being either continuous or composed of discrete protrusions, and fabricated using a molding process that includes a thermoset polyurethane material with closed cell pores.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a hard polishing pad is used, then within-die planarization is improved, but across-wafer uniformity deteriorates due to scratching

Engineering Contradiction:

Improvewithin-die planarizationVSAvoidscratching

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The polishing pad is divided into two distinct layers: a hard foundation layer for structural support and a soft polishing surface layer for actual polishing. This segmentation allows each layer to perform its specific function optimally without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the polishing pad have different hardness properties - the foundation layer is hard while the surface layer is soft. This local quality differentiation enables the pad to provide both structural integrity and gentle polishing action simultaneously.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If a soft polishing pad is used, then scratching is reduced, but within-die planarization deteriorates due to dishing

Engineering Contradiction:

ImprovescratchingVSAvoidwithin-die planarization

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The polishing pad is divided into two distinct layers: a hard foundation layer for structural support and a soft polishing surface layer for actual polishing. This segmentation allows each layer to perform its specific function optimally without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the polishing pad have different hardness properties - the foundation layer is hard while the surface layer is soft. This local quality differentiation enables the pad to provide both structural integrity and gentle polishing action simultaneously.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If the polishing surface and bulk properties are coupled, then fabrication is simplified, but performance is compromised due to inability to optimize both planarization and defect characteristics

Engineering Contradiction:

Improvefabrication simplicityVSAvoidplanarization performance

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The polishing pad is divided into two distinct layers: a hard foundation layer for structural support and a soft polishing surface layer for actual polishing. This segmentation allows each layer to perform its specific function optimally without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The polishing pad uses a composite structure combining two materials with different hardness properties - a hard foundation material and a soft surface polishing material. This composite approach enables optimization of both structural and functional requirements.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS9931728B2Polishing pad with foundation layer and polishing surface layer

Publication Date: 2018.04.03 CMC MATERIALS INC

AI summary

Polishing pads with foundation layers and polishing surface layers are described. In an example, a polishing pad for polishing a substrate includes a foundation layer. A polishing surface layer is bonded to the foundation layer. Methods of fabricating polishing pads with a polishing surface layer bonded to a foundation layer are also described.