Through-Mold Package Connections for Void-Free Board Mounting
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Solution Overview
Problem
Conventional electronic packages face challenges in mounting to circuit boards due to void formation at the interface between solder balls and solder portions, which can lead to defects and increased manufacturing complexity and cost.
Innovation Solution
The electronic package design features a substrate with through-mold connections made of an alloy with a solidus temperature exceeding the liquidus temperature of intermediate solder portions, eliminating the need for a moat or channel around each solder ball, and using a reflow soldering process that avoids liquification of the through-mold connections, ensuring secure and void-free bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solder balls are used with moat or channel structures to prevent void formation, then void formation is reduced, but device complexity and manufacturing steps increase
Solution Approach 1:
The patent removes the moat or channel structure from the mold compound surrounding the solder balls. By eliminating this additional structural feature, the design simplifies the package construction while maintaining effective void prevention through the alternative mechanism of using a reflow soldering process that avoids solder ball liquification.
Solution Approach 2:
Instead of using the moat structure to actively manage void formation, the patent inverts the approach by controlling the soldering process to prevent solder ball melting in the first place. This is achieved by using a reflow soldering process with controlled temperature that keeps the through-mold connections solid, thereby preventing void formation without requiring additional structural features.
2Strength
If reflow soldering is performed at high temperatures to fuse solder portions, then bonding strength is improved, but through-mold connections may liquify causing defects
Solution Approach 1:
The patent changes the temperature parameter of the reflow soldering process to be below the melting point of the through-mold connections. By carefully controlling the reflow temperature to exceed only the solder portion melting point but remain below the through-mold connection melting point, the process achieves strong bonding while preserving connection integrity.
Solution Approach 2:
The patent employs composite material selection where the through-mold connections are made of a material with a melting point significantly higher than the solder portions. This material composition difference creates a temperature window that allows selective melting of solder portions for bonding while keeping the through-mold connections solid and intact.
3Manufacturing precision
If moat or channel structures are created around solder balls, then manufacturing precision is improved for void prevention, but manufacturing complexity increases
Solution Approach 1:
The patent eliminates the laser ablation step used to create moat or channel structures around solder balls. By removing this complex manufacturing operation, the process becomes simpler and more cost-effective while achieving the same void prevention goal through controlled reflow soldering that prevents solder ball melting.
4Reliability
If through-mold connections are made with higher melting point alloy, then reliability during soldering is improved, but manufacturing complexity increases
Solution Approach 1:
The patent changes the material parameter by selecting an alloy composition for the through-mold connections with a melting point above the reflow soldering temperature. This material selection ensures that the through-mold connections remain solid and stable during the soldering process, providing reliability without requiring complex structural designs.
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 simplifies the manufacturing process, reduces void formation, and enhances the reliability of the electronic package's mounting to the circuit board, while maintaining high thermal conductivity and mechanical protection.
Implementation Method 1
The fusing is achieved by a reflow soldering operation in which the package is subject to controlled heat at temperatures sufficient to liquify the solder portions
Implementation Method 2
the through-mold connection configured to have a melting point in excess of a melting point of the intermediate solder portion
Data Source
AI summary
An electronic package is provided. The electronic package includes a substrate configured to receive one or more electronic modules, a first electronic module mounted to a first side of the substrate, a first mold structure extending over at least part of the first side of the substrate; and a group of electrically conductive through-mold connections provided on the first side of the substrate. The first mold structure substantially encapsulates the group of through-mold connections. The group of through-mold connections is exposed through the first mold structure. The group of through-mold connections is configured to couple to a circuit board by a corresponding group of intermediate solder portions. The through-mold connections can have a melting point in excess of a melting point of the intermediate solder portion. Related electronic assemblies, electronic devices, and methods of manufacturing and/or mounting an electronic package are provided.