Polyimide Film Laminated with Inorganic Layer for Dimensional Stability
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Solution Overview
Problem
Polyimide films used in electronic devices face challenges due to a large coefficient of linear expansion, leading to significant dimensional variations with temperature changes, making them unsuitable for manufacturing circuits with microscopic interconnections and restricting their applicable field.
Innovation Solution
A laminated body composed of a plasma-treated polyimide film with a coefficient of linear expansion between -5 ppm/°C to +10 ppm/°C, combined with an inorganic layer such as a glass plate, ceramic plate, or silicon wafer, and a silane-coupling layer, which enhances heat resistance, insulation, and dimensional stability, allowing for precise positioning and peeling without mechanical and dynamical insufficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polyimide film is used as a base material, then heat resistance and flexibility are improved, but coefficient of linear expansion becomes large causing dimensional variation
Solution Approach 1:
The patent applies composite materials by combining polyimide film with inorganic layers (glass, ceramic, or silicon wafer) to create a laminated structure. This composite approach allows the organic polyimide to provide heat resistance and flexibility while the inorganic layer compensates for thermal expansion, achieving a balanced coefficient of linear expansion suitable for precision electronics manufacturing.
2Adaptability or versatility
If polyimide film thickness is decreased, then flexibility is improved, but mechanical strength and dynamical properties deteriorate
Solution Approach 1:
The laminated composite structure provides mechanical reinforcement to thin polyimide films. The inorganic layer acts as a structural support that compensates for the reduced mechanical strength of thin films, enabling the use of ultra-thin polyimide layers (1-50 μm) that maintain both flexibility and adequate mechanical strength for handling and processing.
Solution Approach 2:
The patent segments the base material into multiple functional layers: a thin polyimide film layer providing flexibility and heat resistance, and an inorganic layer providing mechanical strength. This segmentation allows each layer to optimize its specific function while working together as a unified structure.
3Strength
If adhesive layer is added to reinforce polyimide film, then mechanical strength is improved, but heat resistance deteriorates due to low heat resistance of thermoplastic resin
Solution Approach 1:
The patent replaces thermoplastic adhesive layers with inorganic layers (glass, ceramic, or silicon wafer) that provide both mechanical reinforcement and high heat resistance. The inorganic layer bonds to the polyimide film through plasma treatment and silane coupling, creating a composite structure that maintains mechanical strength without sacrificing heat resistance.
Solution Approach 2:
The patent changes the material parameter from organic thermoplastic resin to inorganic material, fundamentally altering the thermal properties of the reinforcement layer. This parameter change enables the reinforcement layer to withstand high temperatures while providing mechanical strength, resolving the contradiction between strength enhancement and heat resistance preservation.
4Strength
If plasma treatment and silane coupling are applied, then peeling strength is improved, but process complexity increases
Solution Approach 1:
The patent applies plasma treatment and silane coupling as preliminary surface preparation steps before lamination. These preliminary actions modify the surface properties of both the polyimide film and inorganic layer to enhance chemical bonding capability, ensuring strong peeling strength while maintaining a relatively simple overall process flow that can be integrated into existing manufacturing lines.
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 laminated structure provides improved heat resistance, flexibility, and dimensional stability, enabling precise production of electronic devices with multiple layers and circuits, while maintaining insulation and allowing for smooth peeling of the polyimide film from the substrate, thus overcoming the limitations of polyimide films alone.
Implementation Method 1
a silane-coupling layer having a thickness of not more than 100 nm is included between the inorganic layer and the polyimide film
Implementation Method 2
180-degree peel strength between the polyimide film and the inorganic layer of the laminated body is not less than 0.5 N/cm and not more than 3 N/cm
Implementation Method 3
a plasma-treated polyimide film obtained by reaction between an aromatic tetracarboxylic acid and an aromatic diamine
Data Source
AI summary
A laminated body for use in device production is provided with which positioning can be performed precisely, peeling after production is smooth, and no peeling occurs during the production process. The laminated body is formed of an inorganic layer such as glass plate and silicon wafer, and a polyimide film obtained by reaction between an aromatic tetracarboxylic acid and an aromatic diamine and having a coefficient of linear expansion in a predetermined range, the inorganic layer and the polyimide film form a laminate without an adhesive layer therebetween, and the 180-degree peel strength between the polyimide film and the inorganic layer of the laminated body is within a predetermined range.