Leadframe Solder Dam for Semiconductor Package
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Solution Overview
Problem
Existing semiconductor package technologies face challenges in securely connecting semiconductor dies to circuit boards and preventing solder tilt and flow without using a spanker, while also ensuring effective heat dissipation and uniform solder distribution.
Innovation Solution
The implementation of a leadframe system with a solder dam around the semiconductor die, where the perimeter of the solder dam is larger than the die, allowing for solder deposition and retention without a spanker, and providing a heatsink configuration that maintains volume while reducing thickness, ensuring secure bonding and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a spanker is used to deposit solder, then solder distribution can be controlled, but the process complexity and additional components increase
Solution Approach 1:
The solder dam structure enables self-contained solder retention and distribution without requiring external spanker tools. The dam's geometry and surface tension properties allow solder to be deposited and held in place automatically, eliminating the need for additional components or complex positioning mechanisms.
Solution Approach 2:
The invention removes the spanker component from the soldering process by integrating solder retention functionality directly into the solder dam structure. This extraction simplifies the overall system by eliminating unnecessary external tools while maintaining solder distribution control.
2Reliability
If the solder dam perimeter is larger than the die perimeter, then solder retention is improved, but the package area increases
Solution Approach 1:
The solder dam is designed with non-uniform geometry where the perimeter extends beyond the die only in specific regions where solder retention is critical. This localized extension provides enhanced solder containment where needed while minimizing the overall area increase of the package.
3Length of stationary object
If the leadframe and heatsink volume is reduced by creating a solder dam opening, then package thickness is reduced, but heat dissipation capability may be compromised
Solution Approach 1:
The solder dam opening creates a through-hole structure that allows heatsink material to extend through the leadframe in the vertical dimension. This dimensional change enables heat dissipation pathways to be maintained or enhanced despite the reduced overall package thickness, as heat can conduct through the opensung structure to external heatsinks.
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 effectively prevents solder tilt and flow, ensures uniform solder distribution, and enhances heat dissipation by using the solder dam's surface tension and encapsulation, while allowing for a reduced package thickness without compromising heat dissipation capabilities.
Implementation Method 1
retaining the solder under the semiconductor die using the solder dam
Implementation Method 2
bonding a first heatsink with the leadframe... ensuring effective heat dissipation
Data Source
AI summary
Leadframe systems and related methods. Specific implementations of leadframe systems may include a die pad, a semiconductor die coupled to the die pad, where the semiconductor die has a perimeter. A leadframe may be coupled over the die pad and the semiconductor die where the leadframe has a solder dam coupled around the semiconductor die and, the solder dam has a perimeter that corresponds with the semiconductor die The die pad may have no groove adjacent to the semiconductor die.