Embedded Substrate Spacer Structure to Prevent Solder Interface Cracks
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Solution Overview
Problem
In typical electronic component-incorporating substrates, insufficient adhesion between the copper core ball and the solder layer of the spacer member can lead to crack formation, reducing the electrical connection reliability between the lower and upper substrates.
Innovation Solution
The electronic component-incorporating substrate employs a spacer member with a spherical solder core ball and a solder layer that covers its circumference, where the melting point of the solder layer is lower than that of the solder core ball. This configuration ensures that the solder layer acts as a bonding material while the solder core ball maintains the separation distance between the substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a copper core ball with solder layer is used as a spacer member, then the spacer maintains the distance between substrates and provides electrical connection, but insufficient adhesion between the copper core ball and solder layer causes crack formation reducing reliability
Solution Approach 1:
The patent changes the material parameters of the spacer member by using a spherical solder ball made of solder material throughout, rather than a copper core with solder layer. This parameter change eliminates the adhesion problem between dissimilar materials (copper and solder) while maintaining the spacer's distance-maintaining and electrical connection functions. The spherical shape and pure solder composition ensure reliable electrical connection without crack formation.
2Ease of manufacture
If reflow soldering is performed to bond the spacer member, then the solder layer bonds the connection pads, but the copper core ball and solder layer interface is prone to cracking due to adhesion issues
Solution Approach 1:
The patent applies homogeneity by making the entire spacer member consist of the same solder material, eliminating the heterogeneous interface between copper core and solder layer. This homogeneous composition ensures uniform bonding during reflow soldering and prevents crack formation at material interfaces, while maintaining ease of manufacture through the standard reflow process.
3Device complexity
If the solder layer acts as bonding material and copper core ball as spacer, then the spacer member provides both functions, but the interface between them reduces electrical connection reliability
Solution Approach 1:
The patent applies multi-functionality by using a single spherical solder ball to perform both the spacer function (maintaining distance) and the bonding function (providing electrical connection). This eliminates the need for a complex copper core-solder layer composite structure, reducing device complexity while improving reliability through a homogeneous, crack-free design that maintains both spacing and electrical connectivity.
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 design enhances the electrical connection reliability by preventing crack formation within the spacer member, even if manufacturing errors occur, and maintains the specified separation distance between the substrates.
Implementation Method 1
A melting point of the solder layer is lower than a melting point of the solder core ball
Data Source
AI summary
An electronic component-incorporating substrate includes a first substrate, a second substrate, a spacer member, an electronic component, and an encapsulation resin. The first substrate includes a first connection pad. The second substrate includes a second connection pad that faces the first connection pad. The spacer member electrically connects the first connection pad and the second connection pad. The electronic component is mounted on the first substrate and is disposed between the first substrate and the second substrate. The encapsulation resin fills a gap between the first substrate and the second substrate and encapsulates the electronic component. The spacer member includes a spherical solder core ball and a solder layer that covers a circumference of the solder core ball. A melting point of the solder layer is lower than a melting point of the solder core ball.