CMP Pad Photopolymerization Planarization

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Solution Overview

Problem

Current chemical mechanical polishing (CMP) pads do not achieve optimal planarization performance and productivity for semiconductor wafers, which is crucial for removing surface topography and defects in advanced semiconductor devices.

Innovation Solution

A CMP pad with a polishing layer formed by extruding a photopolymerizable composition comprising a block copolymer, UV curable acrylate, and photoinitiator, where the block copolymer is present at greater than 50 wt%, and upon UV curing, the pad achieves a Shore D hardness of 40 to 70, enhancing polishing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional CMP pads are used, then basic polishing function is provided, but optimal planarization performance and productivity are not achieved

Engineering Contradiction:
Improveplanarization performanceVSAvoidpolishing performance consistency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the polishing pad by incorporating specific ratios of polyurethane polymer (5-20 parts), silica particles (80-150 parts), and metal oxide particles (10-30 parts). These parameter changes in material composition directly improve planarization performance while maintaining polishing consistency through optimized formulation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses composite materials by combining polyurethane polymer base material with silica particles and metal oxide particles to create a multi-component polishing pad structure. This composite approach enables simultaneous achievement of high productivity through silica abrasion and improved reliability through metal oxide surface conditioning, resolving the contradiction between performance and consistency.

Inventive Principle:
Principle #40Composite materials

2Strength

If photopolymerizable composition with block copolymer is used, then Shore D hardness of 40 to 70 is achieved, but manufacturing complexity increases

Engineering Contradiction:
ImproveShore D hardnessVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical mixing and curing processes with photopolymerization technology. The composition includes photoinitiators that enable UV-light-induced curing, substituting thermal or mechanical curing methods. This achieves precise control over Shore D hardness (40-70) while the extrusion-based manufacturing process actually simplifies production compared to multi-step conventional methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention utilizes phase transition during photopolymerization, where the liquid or soft polymer composition transforms into a cured solid structure with controlled hardness. The block copolymer structure enables this phase transition to occur at controlled rates during UV exposure, achieving the target Shore D hardness range while maintaining manufacturing simplicity through a single-cure process.

Inventive Principle:
Principle #36Phase transitions

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 CMP pad demonstrates improved planarization performance and productivity, with a Shore D hardness range of 40 to 70, providing better surface smoothing and defect removal for semiconductor wafers.

Implementation Method 1

a photopolymerizable composition comprising a block copolymer, a UV curable acrylate, and a photoinitiator

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

UV curable acrylate, and a photoinitiator, wherein said block copolymer is present at an amount of greater than 50 wt %

Methodology Applied
Scientific EffectPhotochemical reaction: Photo-oxidation

Data Source

PatentUS11679531B2Chemical mechanical polishing pad and preparation thereof
Publication Date: 2023.06.20 DUPONT ELECTRONICS INC

AI summary

The present invention concerns a chemical mechanical polishing pad having a polishing layer. The polishing layer contains an extruded sheet. The extruded sheet is prepared by extruding a compounded photopolymerizable composition followed by exposure to UV light.