Curable Resin Composition with Segmented Silica for Narrow Wiring Embeddability

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Solution Overview

Problem

The existing photosensitive resin compositions face challenges in embeddability between narrow wirings, leading to potential insulation failures in printed wiring boards, and require higher insulation reliability, especially with increasing density, where current HAST resistance evaluations may be insufficient for narrower line/space configurations.

Innovation Solution

A curable resin composition comprising a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting resin, and silica with specific particle size and association characteristics, including nanosilica with an average secondary particle size of 200 nm or less and a degree of association of 2.3 or less, which enhances embeddability and insulation reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a photosensitive resin composition containing silica with average particle size of less than 50 nm is used, then fine opening patterns can be formed without impairing developability, but embeddability between narrow wirings deteriorates

Engineering Contradiction:
Improvefine opening pattern formationVSAvoidembeddability between narrow wirings
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The silica particles are segmented into two distinct size ranges: first silica with 10-50 nm average particle size for fine pattern formation, and second silica with 50-200 nm average particle size for improved embeddability. This segmentation allows each particle size to fulfill its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite silica system combining two different silica particle sizes (10-50 nm and 50-200 nm) within the same resin composition. This composite approach leverages the fine filling and pattern-forming capability of smaller particles while the larger particles provide better flow and embeddability properties.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the HAST resistance evaluation uses a comb-shaped electrode with line/space of 50 μm/50 μm, then insulation reliability can be assessed, but the evaluation is insufficient for narrower line/space configurations required by higher density printed wiring boards

Engineering Contradiction:
Improveinsulation reliability assessmentVSAvoidapplicability to narrower line/space configurations
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention changes the particle size parameters of silica from a single narrow range (less than 50 nm) to a broader dual-range distribution (10-50 nm and 50-200 nm). This parameter modification enables the resin composition to maintain performance across varying wiring densities and line/space configurations, making it adaptable to both current 50 μm standards and future narrower configurations.

Inventive Principle:
Principle #35Parameter changes

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 curable resin composition provides excellent resolution and higher insulation reliability, enabling better embeddability in circuits and maintaining characteristics like coatability and crack resistance, thus addressing the limitations of existing resin compositions.

Implementation Method 1

a curable resin composition comprising: (A) a carboxyl group-containing resin; (B) a photopolymerization initiator; (C) a thermosetting resin

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS20240191072A1Curable resin composition, dry film, cured product, and electronic component
Publication Date: 2024.06.13 TAIYO HOLDINGS CO LTD

AI summary

Provided are a curable resin composition, a dry film, a cured product, and an electronic component including the same that have excellent resolution, higher insulation reliability, and excellent embeddability in a circuit. A curable resin composition includes: (A) a carboxyl group-containing resin; (B) a photopolymerization initiator; (C) a thermosetting resin; and (D) silica, wherein a blending amount of (D) the silica is 10 to 60% by mass relative to a total solid content of the curable resin composition, (D) the silica includes (D-1) nanosilica, (D-1) the nanosilica has an average secondary particle size of 200 nm or less, and a degree of association of (D-1) the nanosilica is 2.3 or less.