Circuit Board Flow Pins for Void-Free Stacked Semiconductor Molding
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Solution Overview
Problem
Conventional semiconductor devices face issues with void generation due to air trapping during the transfer molding process, leading to defective devices with compromised strength and insulation, especially in stacked module structures where controlling resin flow velocity is challenging.
Innovation Solution
The semiconductor device incorporates flow velocity control pins on the circuit board, strategically positioned to adjust the resin confluence points and equalize flow velocities, reducing void formation by providing resistance to the resin flow and ensuring air escape through the air vent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transfer molding is performed without flow velocity control, then the manufacturing process is simple, but voids are generated due to air trapping from uneven resin flow
Solution Approach 1:
The patent introduces flow velocity control pins as intermediary elements that mediate between the injection mold and the semiconductor module. These pins create controlled resistance to resin flow, equalizing flow velocities across different regions and preventing air trapping. The pins serve as a mechanical mediator that transforms the uneven flow pattern into a uniform flow pattern, eliminating voids without requiring complex process changes.
Solution Approach 2:
The patent changes the physical parameters of the molding process by introducing pins with specific dimensions, materials, and positioning. The pins have different heights, diameters, and locations optimized to control resin flow velocity in specific regions. By adjusting these physical parameters, the resin flow pattern is modified to achieve uniform filling and prevent void formation while maintaining process simplicity.
2Productivity
If resin flow velocity is increased to improve productivity, then molding cycle time is reduced, but voids are generated due to air trapping
Solution Approach 1:
The patent applies local quality by positioning flow velocity control pins at specific locations where resin flow velocity needs to be reduced. The pins are strategically placed in regions prone to air trapping, creating localized flow resistance only where needed. This allows the overall resin flow velocity to remain high for productivity while locally controlling velocity to prevent voids, achieving both productivity and reliability goals.
3Reliability
If uniform resin flow velocity is achieved to prevent voids, then dielectric withstand voltage is improved, but additional flow control components are required
Solution Approach 1:
The flow velocity control pins act as intermediaries that create uniform resin flow velocity across the molding cavity. By introducing these pins, the resin flows at controlled velocities that prevent air trapping and ensure complete filling of the module. This uniform flow pattern eliminates voids, thereby improving dielectric withstand voltage and reliability without requiring complex additional components beyond the pins themselves.
4Manufacturing precision
If flow velocity control pins are added to equalize resin flow, then void formation is reduced, but manufacturing complexity increases
Solution Approach 1:
The flow velocity control pins are prepared in advance with specific dimensions, materials, and positioning information. The pins are pre-manufactured with optimized heights, diameters, and locations determined through simulation and experimentation. This preliminary preparation allows for easy integration into the molding process, as the pins can be directly installed in the mold cavity before injection, simplifying the overall manufacturing process while achieving precise void formation control.
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 reduces void generation, enhances the dielectric withstand voltage, and improves the reliability of semiconductor devices by controlling resin flow and alleviating stress-related issues such as warpage and cracking.
Implementation Method 1
providing resistance to the resin flow and equalizing flow velocities
Data Source
AI summary
A semiconductor device, including: a stacked substrate; a plurality of semiconductor chips provided on the stacked substrate; an external output terminal; a circuit board configured to electrically connect the plurality semiconductor chips, and to electrically connect the plurality of semiconductor chips to the external output terminal, the circuit board having a first surface and a second surface opposite to each other, the second surface facing the stacked substrate; a sealing resin sealing the stacked substrate and the circuit board; and a plurality of flow velocity control pins attached to the circuit board, at the first surface of the circuit board.