Conductive Resin Shield Coating for Package EMI Adhesion
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Solution Overview
Problem
Current conductive pastes fail to effectively shield electromagnetic waves in the 10 MHz to 1000 MHz range and often suffer from decreased adhesion between the shield layer and the package, especially during high-temperature processes like solder reflow.
Innovation Solution
A conductive resin composition comprising a (meth)acrylic resin, monomers with glycidyl or (meth)acryloyl groups, conductive fillers with specific particle sizes, and a radical polymerization initiator, applied via spray coating to form a shield layer with enhanced adhesion and shielding properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nanosized conductive filler is used to improve shielding properties, then shielding effectiveness improves, but adhesion between shield layer and package decreases during high-temperature processes
Solution Approach 1:
The patent uses a composite resin system combining (meth)acrylic resin with epoxy group-containing compounds and isocyanate group-containing compounds. This creates a multi-component resin system that provides both nanosized conductive filler dispersibility and high-temperature adhesion resistance, resolving the contradiction between shielding effectiveness and adhesion strength.
Solution Approach 2:
The patent specifies precise molecular weight ranges for the (meth)acrylic resin (1,000-400,000) and controlled resin composition ratios to optimize both nanosized filler dispersibility and adhesion performance. By adjusting resin parameters and composition, the patent achieves both good shielding properties and adhesion resistance during solder reflow processes.
2Reliability
If large amount of conductive filler is blended to improve shielding properties against 10 MHz to 1000 MHz electromagnetic waves, then shielding effectiveness improves, but adhesion between shield layer and package deteriorates
Solution Approach 1:
The patent employs a composite resin system consisting of (meth)acrylic resin combined with epoxy group-containing compounds and isocyanate group-containing compounds. This composite approach enables the resin to simultaneously provide excellent dispersibility for large amounts of conductive filler and maintain strong adhesion during high-temperature solder reflow processes.
Solution Approach 2:
The patent controls the molecular weight of (meth)acrylic resin within 1,000-400,000 and specifies precise composition ratios to optimize the balance between conductive filler loading capacity and adhesion performance. This parameter optimization allows achieving both improved shielding effectiveness and maintained adhesion strength.
3Stability of the object's composition
If (meth)acrylic resin is used to improve dispersibility of nanosized conductive filler, then filler dispersibility improves, but adhesion between shield layer and package decreases when exposed to high temperature
Solution Approach 1:
The patent creates a composite resin system where (meth)acrylic resin is combined with epoxy group-containing compounds and isocyanate group-containing compounds. The (meth)acrylic resin provides nanosized filler dispersibility while the epoxy and isocyanate components provide high-temperature adhesion resistance, resolving the contradiction between dispersibility and adhesion.
Solution Approach 2:
The patent specifies the molecular weight of (meth)acrylic resin within 1,000-400,000 and controls the resin composition ratios to optimize both nanosized filler dispersibility and adhesion performance during solder reflow, achieving both good dispersibility and adhesion strength.
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 solution provides a uniform shield layer with excellent shielding effectiveness against electromagnetic waves and maintains strong adhesion to the package, even after high-temperature processing, without requiring large-scale apparatus.
Implementation Method 1
a step of coating a surface of the individualized package by spraying with the conductive resin composition according to any one of claims 1 to 4; a step of forming the shield layer by heating the substrate having the surface of the package coated with the conductive resin composition and by curing the conductive resin composition
Implementation Method 2
a step of coating a surface of the individualized package by spraying with the conductive resin composition
Data Source
Figure 1(a)~2
Figure 3
AI summary
Provided are a conductive resin composition in which a shield layer having good shielding properties even against electromagnetic waves of 10 MHz to 1000 MHz and having good adhesion to a package can be formed by spray coating, and a method for manufacturing a shielded package using the conductive resin composition. The conductive resin composition contains at least: (A) a (meth)acrylic resin having a weight average molecular weight of 1,000 or more and 400,000 or less; (B) a monomer having a glycidyl group and/or a (meth)acryloyl group in its molecule; (C) a conductive filler having an average particle diameter of 10 to 500 nm; (D) a conductive filler having an average particle diameter of 1 to 50 µm; and (E) a radical polymerization initiator. A sum of the content of the conductive filler (C) and the content of the conductive filler (D) is 2,000 to 80,000 parts by mass based on 100 parts by mass of the total amount of the (meth)acrylic resin (A) and the monomer (B). A content ratio of the conductive filler (C) and the conductive filler (D) (the conductive filler (C): the conductive filler (D)) is 5:1 to 1:10 by mass ratio.