Mounting Substrate Resist Film Receiving Portion
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Solution Overview
Problem
Existing mounting substrates face issues with connection electrodes becoming peeled off due to thermal stress and external forces, and the risk of conductive bonding material flowing out and forming chip-side balls, leading to unreliable electronic component mounting.
Innovation Solution
A mounting substrate design featuring a resist film that covers the peripheral edge of connection electrodes and includes receiving portions to manage excess conductive bonding material, preventing flow-out and chip-side ball formation, ensuring proper orientation and reliability of electronic component mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the peripheral edge portion of the connection electrode is covered by solder resist, then the connection electrode is protected from peeling off due to thermal stress and external forces, but the conductive bonding material may flow out and form chip-side balls
Solution Approach 1:
The solder resist film is segmented by forming a receiving portion (opening) that divides the coverage area. This segmentation allows the solder resist to cover the connection electrode for protection while creating a designated space to contain the conductive bonding material, preventing it from flowing out and forming chip-side balls.
Solution Approach 2:
The receiving portion acts as an intermediary structure between the covered connection electrode and the external environment. It provides a controlled space that mediates the containment of excess conductive bonding material, preventing direct contact with surrounding areas where chip-side balls could form.
2Ease of manufacture
If the connection electrode is entirely exposed from the solder resist, then the conductive bonding material can be applied freely, but the connection electrode becomes susceptible to peeling off due to thermal stress and external forces
Solution Approach 1:
The solder resist film applies local quality by covering specific areas of the connection electrode (the peripheral edge portion) while leaving other areas exposed. This selective coverage provides protection where needed (at the edges susceptible to peeling) while maintaining accessibility for conductive bonding material application in the exposed central area.
3Reliability
If the peripheral edge portion of the connection electrode is covered by solder resist, then the connection electrode is protected from peeling off, but the electronic component may be mounted in an unsatisfactory orientation due to flow-out of conductive bonding material
Solution Approach 1:
The receiving portion converts the potential harm of excess conductive bonding material flow-out into a beneficial containment function. By providing a designated space within the solder resist film, the structure that could have caused mounting orientation problems instead ensures proper component placement by containing the bonding material within acceptable boundaries.
Data Source
AI summary
A mounting substrate includes a substrate, a connection electrode, which is formed on a front surface of the substrate and on which an electronic component is mounted via a conductive bonding material, a resist film, formed on the front surface of the substrate so as to cover a peripheral edge portion of the connection electrode, and a receiving portion, formed in the resist film so as to expose a portion of the peripheral edge portion of the connection electrode and arranged to receive an excess portion of the conductive bonding material.