Prepreg Resin Composition for Fine Circuit Adhesion
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Solution Overview
Problem
Conventional resin compositions for printed wiring boards face challenges in achieving both high adhesion to fine circuit patterns and sufficient hygroscopic heat resistance, particularly when using the semi-additive method, as they often compromise on one property to enhance the other.
Innovation Solution
A prepreg comprising a woven fabric base filled and coated with a semi-cured resin composition that includes a thermosetting resin, an inorganic filler, a thermoplastic resin soluble in an organic solvent, and a thermoplastic resin insoluble in an organic solvent, with specific content ratios and types, such as epoxy resin, silica, and core-shell rubber, to provide both high adhesion and excellent hygroscopic heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thin electroless plating layer is formed on an insulating layer by electroless plating to create fine circuit patterns, then fine circuit patterns can be formed, but adhesion strength between the insulating layer and the circuit patterns becomes low
Solution Approach 1:
The patent uses a composite resin composition containing both a thermosetting resin (epoxy resin) and a thermoplastic resin (acrylic resin). The thermosetting resin provides structural integrity and adhesion, while the thermoplastic resin fills gaps and enhances bonding to the electroless plating layer. This composite approach allows fine circuit patterns to be formed while maintaining high adhesion strength.
Solution Approach 2:
The patent specifies precise compositional parameters for the resin, including the content ratio of inorganic filler (50-150 parts by mass per 100 parts by mass of thermosetting resin) and the total content ratio of thermoplastic resins (20-50 parts by mass per 100 parts by mass of thermosetting resin). These parameter optimizations ensure both fine pattern formation capability and high adhesion strength.
2Ease of manufacture
If the insulating layer undergoes a reflow process during substrate working, then substrate processing can be completed, but delamination defects may occur due to insufficient hygroscopic heat resistance
Solution Approach 1:
The patent optimizes the resin composition parameters, specifically the inorganic filler content (50-150 parts by mass per 100 parts by mass of thermosetting resin) and thermoplastic resin content (20-50 parts by mass per 100 parts by mass of thermosetting resin). This composition provides excellent hygroscopic heat resistance, preventing delamination during reflow processes while maintaining ease of manufacture.
Solution Approach 2:
The thermoplastic resin component in the composite formulation acts as a cushioning agent that prevents delamination during subsequent reflow and soldering processes. The specific composition ratios ensure the resin has sufficient flexibility and adhesion to accommodate thermal stress without failing, thereby preventing defects before they occur.
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 proposed solution enables the formation of fine circuit patterns with enhanced adhesion and hygroscopic heat resistance, improving the reliability and performance of printed wiring boards in electronic devices by balancing adhesion and thermal stability.
Implementation Method 1
a semi-cured product of a resin composition, which fills an inside of the woven fabric base and coats a surface of the woven fabric base. The resin composition includes a thermosetting resin
Implementation Method 2
an inorganic filler... With respect to 100 parts by mass of the thermosetting resin, a content ratio of the inorganic filler ranges from 50 parts by mass to 150 parts by mass, inclusive
Implementation Method 3
a first thermoplastic resin soluble in an organic solvent... fine circuit patterns can be formed with use of a semi-additive method, while ensuring excellent hygroscopic heat resistance and high adhesion to the circuit patterns
Data Source
AI summary
A prepreg includes: a woven fabric base; and a semi-cured product of a resin composition, which fills an inside of the woven fabric base and coats a surface of the woven fabric base. The resin composition includes a thermosetting resin, an inorganic filler, a first thermoplastic resin soluble in an organic solvent, and a second thermoplastic resin insoluble in an organic solvent. With respect to 100 parts by mass of the thermosetting resin, a content ratio of the inorganic filler ranges from 50 parts by mass to 150 parts by mass, inclusive, and a total content ratio of the first thermoplastic resin and the second thermoplastic resin ranges from 20 parts by mass to 50 parts by mass, inclusive.