Transparent Adhesive Film for Alignment Mark Visibility and Stability
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Solution Overview
Problem
Film-shaped transparent adhesives used in optical and semiconductor devices face challenges with maintaining transparency and storage stability, particularly when cured, and often suffer from reduced visibility of alignment marks due to the use of conventional epoxy resin-curing agents at room temperature.
Innovation Solution
A transparent adhesive composition comprising an epoxy resin, an epoxy resin-curing agent in powdery form with specific particle diameter and low solubility, and a phenoxy resin, along with a silica filler, is used to enhance transparency and storage stability, ensuring high visibility of alignment marks and maintaining adhesive performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional epoxy resin-curing agent is used at room temperature to enhance storage stability, then storage stability is improved, but transparency decreases resulting in poor recognition of alignment marks
Solution Approach 1:
The patent applies parameter changes by specifying precise particle diameter ranges (d50: 0.5-2.0 μm, d90: 2.0-5.0 μm) and solubility limits (0.01-1.0 g/100g at 25°C) for the epoxy resin-curing agent. These parameter optimizations resolve the contradiction by finding the optimal balance point where the curing agent provides sufficient storage stability while maintaining transparency below 5% haze for alignment mark visibility.
Solution Approach 2:
The patent uses composite materials by combining the epoxy resin-curing agent with specific resin systems (epoxy resin, polyester resin, or vinyl ester resin) and fillers. This composite approach allows the curing agent to contribute storage stability while the overall composition maintains transparency, achieving both improved reliability and preserved optical properties.
2Strength
If the adhesive is cured to achieve bonding performance, then bonding strength is improved, but transparency is reduced making alignment marks less visible
Solution Approach 1:
The patent applies parameter changes by controlling the particle diameter distribution (d50: 0.5-2.0 μm, d90: 2.0-5.0 μm) and solubility (0.01-1.0 g/100g) of the epoxy resin-curing agent. These optimized parameters enable the adhesive to achieve strong bonding performance upon curing while maintaining transparency with haze below 5%, thus preserving alignment mark visibility.
Solution Approach 2:
The patent employs fine particle sizing of the curing agent that replicates the transparency characteristics of the uncured state in the cured state. The small particle diameter (d50: 0.5-2.0 μm) allows the cured adhesive to maintain optical clarity similar to the uncured adhesive, enabling alignment marks to remain visible after bonding.
3Ease of operation
If paste-like adhesive is used for bonding, then ease of application is improved, but protrusion from adhesion site occurs
Solution Approach 1:
The patent applies this principle by using a film-shaped adhesive with controlled viscosity and particle distribution. The thin film structure prevents protrusion from the adhesion site while the flexible rheological properties (optimized through particle diameter control) maintain ease of application and bonding performance.
4Measurement precision
If alignment marks are structured more finely to improve precision, then measurement precision is improved, but visibility through adhesive decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the epoxy resin-curing agent properties (particle diameter d50: 0.5-2.0 μm, d90: 2.0-5.0 μm; solubility: 0.01-1.0 g/100g) to achieve haze below 5%. This creates an optical environment where even fine alignment marks remain visible through the cured adhesive, maintaining both measurement precision and visibility.
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 adhesive composition maintains excellent transparency and storage stability, allowing for effective bonding and protection of optical and semiconductor components while preserving alignment mark visibility.
Implementation Method 1
In a film-shaped transparent adhesive using an epoxy resin, it has been known to use a solid epoxy resin-curing agent at room temperature in order to enhance storage stability
Implementation Method 2
the thermosetting temperature was set to a relatively low temperature (e.g., about 120° C.)
Data Source
AI summary
A transparent adhesive composition including an epoxy resin (A), an epoxy resin-curing agent (B), and a phenoxy resin (C), wherein the epoxy resin-curing agent (B) satisfies the following (1) and (2):(1) the epoxy resin-curing agent (B) is in a powdery form and has a particle diameter (d90) at 90% cumulative distribution frequency of 2.0 μm or less; and(2) the epoxy resin-curing agent (B) has solubility in 100 g of methyl ethyl ketone at 25° C. of 0.1 g or less;a film-shaped transparent adhesive processed therefrom;a method of producing a transparent adhesive cured layer-attached member by using the film-shaped transparent adhesive;a method of producing an electronic component; andan electronic component.