Novolak Phenolic Epoxy Resin for Reliable Chip Bonding
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Solution Overview
Problem
Conventional non-conductive films (NCFs) used in packaging electronic components on printed circuit boards face issues with connection reliability due to fast curing initiation by imidazole-based epoxy resin compositions, which can result in insufficient reliability and transparency, making it difficult to visually check alignment marks.
Innovation Solution
The use of a novolak phenolic curing agent and an acrylic elastomer copolymer containing dimethyl acrylamide and hydroxyethyl methacrylate, combined with an inorganic filler, in the epoxy resin composition slows down curing initiation and enhances transparency, ensuring high connection reliability and ease of alignment mark recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If imidazole-based epoxy resin composition is used, then curing initiation becomes faster, but connection reliability becomes insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the curing agent system, replacing pure imidazole with a combination of novolak phenolic curing agent and imidazole. This parameter change slows down the curing initiation speed while maintaining adequate connection reliability, resolving the contradiction between fast curing and reliable connection.
2Speed
If imidazole-based epoxy resin composition is used, then curing initiation becomes faster, but transparency deteriorates
Solution Approach 1:
The patent modifies the chemical composition parameters by introducing novolak phenolic curing agent alongside imidazole, which changes the curing kinetics to be slower and produces a more transparent cured product. This resolves the contradiction between fast curing initiation and transparency by adjusting the compositional parameters.
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 achieves excellent connection reliability and transparency, allowing for reliable bonding and easy alignment mark recognition, as demonstrated by improved bonding strength and resistance to wet heat reflow.
Implementation Method 1
the reaction of curing initiation becomes faster, with the consequence that sufficient connection reliability may not be achieved
Implementation Method 2
an acrylic elastomer, an epoxy resin and an inorganic filler, wherein the acrylic elastomer is a copolymer containing dimethylacrylamide and hydroxyethyl methacrylate
Data Source
AI summary
An epoxy resin composition having excellent connection reliability and transparency, a method for manufacturing a composite unit using the epoxy resin composition, and the composite unit, are disclosed. The manufacturing method includes an attaching step of attaching an epoxy resin composition (2) containing a novolak phenolic curing agent, an acrylic elastomer composed of a copolymer containing dimethylacrylamide and hydroxylethyl methacrylate, an epoxy resin and not less than 5 parts by weight to not more than 20 parts by weight of an inorganic filler to 100 parts by weight of the epoxy resin, to a printed circuit board (1) in the form of a sheet. The manufacturing method also includes a temporary loading step of temporarily loading a semiconductor chip (3) and capacitors (4a) to (4d) on the epoxy resin composition (2) and an ultimate pressure bonding step of pressuring the semiconductor chip (3) and capacitors (4a) to (4d) by a thermal bonding head (20) in situ to ultimately pressure bond the semiconductor chip (3) and capacitors (4a) to (4d).