Electronic Card Sub-Cavity Adhesive Reservoir for Hot Pressing
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Solution Overview
Problem
The existing methods for manufacturing electronic cards face issues with establishing reliable electrical connections between embedded modules and chips due to the displacement of electrically conductive adhesives during hot pressing, leading to potential loss of connection and inadequate pressure on anisotropic conductive films (ACFs).
Innovation Solution
A sub-cavity is created at the bottom of the main cavity in the card body, which serves as an adhesive reservoir to ensure proper distribution and pressure application of the conductive adhesive, enhancing the electrical connection between the module's contact pads and the connection bump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure is applied to the module during hot pressing to establish electrical connection, then the electrical connection between module and contact plate is improved, but the electrically conductive adhesive is driven out from the cavity areas with less pressure, causing loss of connection
Solution Approach 1:
The invention introduces a vertical sub-cavity dimension beneath the cavity bottom to provide a three-dimensional adhesive reservoir. This vertical extension allows adhesive to be stored in a deeper zone that is less susceptible to horizontal pressure-driven displacement, thereby maintaining electrical connection reliability while accommodating the necessary adhesive volume.
Solution Approach 2:
The sub-cavity acts as an intermediary adhesive reservoir between the applied pressure and the critical electrical connection interface. By positioning the adhesive storage zone in this intermediate vertical location, the system buffers the effect of pressure on adhesive displacement while ensuring adequate adhesive availability at the contact interface.
2Strength
If pressure is applied hot to the module to establish electrical connection, then the bonding between module and contact surface is improved, but the adhesive is driven out particularly in areas with less pressure, leading to inadequate connection
Solution Approach 1:
The sub-cavity creates a vertical dimension for adhesive storage that is decoupled from the horizontal pressure distribution. This allows the adhesive to be heated and pressed effectively at the bonding interface while the reservoir portion remains protected from pressure-driven extrusion, maintaining both bonding strength and connection reliability.
Solution Approach 2:
The sub-cavity provides beforehand cushioning by pre-positioning excess adhesive in a protected vertical zone before pressure application. This cushioning reservoir compensates for adhesive loss during the hot pressing process, ensuring adequate adhesive remains at the bonding interface to maintain both strength and reliability.
3Ease of manufacture
If the cavity is formed by machining to a single depth to accommodate the connection bump, then the manufacturing process is simplified, but the adhesive cannot be properly pressed and distributed, resulting in poor electrical connection
Solution Approach 1:
The cavity is segmented into two functional zones: an upper working cavity for module placement and a lower sub-cavity for adhesive reservoir. This segmentation allows each zone to be optimized for its specific function while maintaining relative manufacturing simplicity through sequential or integrated machining operations.
Solution Approach 2:
The solution transitions from a single-depth cavity to a multi-level cavity structure with vertical differentiation. The sub-cavity extends downward from the main cavity bottom, creating a two-tier vertical architecture that enables both simplified manufacturing (through standard machining) and precise adhesive distribution control (through controlled vertical depth variation).
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
This solution ensures a stable and reliable electrical connection by allowing the adhesive to flow into the sub-cavity, maintaining contact and pressure distribution, thereby improving the bonding between the module and the card's contact surface, even under hot pressing conditions.
Implementation Method 1
pressure is applied to it, in particular hot, however, the application of pressure has the effect of driving out the adhesive
Data Source
Figure 1~3
Figure 4~5
AI summary
This application relates to an electronic circuit board (20) comprising a body (10) including a FPC (1), a cavity (11) formed in the body (10) having a bottom (12) in which a contact surface (5) of a bump (4) of the FPC (1) appears, and a module (30) embedded in the cavity (11) having an inner face (32) having at least one electrical contact area. A layer of electrically conductive adhesive (33) covers the inner face (32) of the module to electrically connect the electrical contact area of the module to the contact surface (5) located at the bottom (12) of the cavity (11), and a sub-cavity (13) is formed in the bottom (12) of the cavity (11), at a distance from a periphery of the cavity (11), and is filled at least partially with electrically conductive adhesive (33). It also relates to a method for manufacturing such an electronic circuit board (20).