Dual Side PCB Molding with Independent Actuators
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Solution Overview
Problem
Current substrate over-molding technologies primarily utilize single-sided molding techniques, which are inadequate for system miniaturization and do not effectively address the need for dual side molding in package architecture, particularly for system in package (SiP) designs where components are laid out on a fine pitch and require reliability and shielding.
Innovation Solution
A dual side package molding technique using a molding assembly with front and back mold blocks, where independent actuators control the injection of molding compounds into both sides of a substrate through specific runner and cavity configurations, enabling balanced flow and pressure management across both sides, even when component layouts differ.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If single-sided molding technique is used, then device complexity is reduced, but manufacturing precision and reliability are insufficient for dual side package requirements
Solution Approach 1:
The molding assembly is segmented into front and back mold blocks, each with independent cavities and runner systems. This segmentation enables simultaneous dual side molding while maintaining control over each side's molding parameters, resolving the contradiction between manufacturing precision and device complexity.
Solution Approach 2:
The invention transitions from single-sided (one-dimensional) molding to dual-sided (two-dimensional) molding by adding molding capability in the opposite direction of the substrate. This dimensional expansion enables simultaneous encapsulation of components on both sides of the PCB, achieving high manufacturing precision for dual side packages.
2Manufacturing precision
If independent actuators are used for front and back mold blocks, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The actuator system is segmented into front and back actuators that operate independently. Each actuator controls its respective mold block's cavity pressure and molding parameters, enabling precise control for dual side molding while maintaining manageable system complexity through modular design.
Solution Approach 2:
The independent actuators provide dynamic control over the molding process for each side of the substrate. This dynamic capability allows real-time adjustment of cavity pressures and molding speeds to achieve balanced flow and prevent substrate bending, resolving the contradiction between manufacturing precision and device complexity.
3Manufacturing precision
If longer runners are used for front and back cavities, then manufacturing precision is improved, but loss of substance increases
Solution Approach 1:
The runner system is designed with local quality variations, where runner lengths and diameters are optimized for each specific cavity's requirements. This localized optimization ensures proper molding compound distribution to both front and back cavities while minimizing overall material waste, resolving the contradiction between manufacturing precision and loss of substance.
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 approach allows for simultaneous dual side molding of substrates, ensuring balanced cavity pressures and preventing bending or collapse, while being compatible with conventional degating systems and enabling efficient encapsulation of components on both sides of the substrate.
Implementation Method 1
injecting a first molding compound through the first runner and into the front cavity of the front mold block
Data Source
AI summary
Molding assemblies and methods for dual side package molding are described. In an embodiment, a molding compound is injected into a front cavity with a first actuator, and a molding compound is injected into a back cavity with a second actuator, with the first and second actuator assemblies being independently controlled. In an embodiment, the molding compound flows through a through-hole in a molding substrate from a front side of the molding substrate to a back side of the molding substrate, and into the back cavity.