Composite Substrate Molding Layer for Bubble Elimination
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Solution Overview
Problem
Conventional printed circuit board (PCB) packaging processes often result in bubble formation due to inconsistent metal deposition rates, leading to reliability issues during subsequent testing, such as temperature cycling tests, and potential short-circuiting due to arcing phenomena.
Innovation Solution
The package incorporates a composite substrate with conductive layers, conductive vias filled with a molding layer, and a support layer, where the molding layer is formed by laminating insulating sheets to fill conductive vias and accommodating spaces, reducing bubble formation and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal deposition is performed to form conductive pillar in through hole, then electrical connection between metal layers is achieved, but bubbles are formed due to inconsistent deposition rates causing reliability issues
Solution Approach 1:
The invention extracts and removes the harmful bubbles from the conductive pillar structure by using a cleaning process that eliminates trapped air during metal deposition, thereby maintaining electrical connection reliability without the harmful bubble formations
Solution Approach 2:
The invention changes the deposition parameters and process conditions to achieve more uniform metal deposition throughout the through hole, reducing the deposition rate difference between opening and interior to prevent bubble formation while maintaining electrical connectivity
2Ease of manufacture
If insufficient insulator is used to fill accommodating space, then packaging process is simplified, but bubbles remain causing arcing paths and short circuits
Solution Approach 1:
The invention performs preliminary action by pre-forming the insulator layer with sufficient thickness before die mounting, ensuring that the insulator will completely fill the accommodating space after die attachment, thereby preventing bubble formation and arcing paths while maintaining packaging simplicity
Solution Approach 2:
The invention provides beforehand cushioning by using excess insulator material that compensates for potential filling gaps, ensuring complete coverage and eliminating voids that could create arcing paths, thus protecting against electrical short circuits
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 bubble formation and associated air pressure issues, improving the reliability of the package by preventing conductive pillar breakage and arcing, thereby stabilizing electrical performance.
Implementation Method 1
the first insulating sheet and the second insulating sheet are heated to a semi-curing state to flow into and fill the at least one conductive via and the accommodating space
Implementation Method 2
heated to a semi-curing state to flow into and fill
Data Source
AI summary
A package capable of eliminating bubble formation includes a composite substrate having an accommodating space, an upper conductive layer and a lower conductive layer; at least one conductive via formed in the composite substrate and electrically connected to the upper conductive layer and the lower conductive layer; a die mounted in the accommodating space and having a first surface and a second surface; a molding layer covering the composite substrate and filled in the at least one conductive via and the accommodating space to wrap the die; the support layer buried in the molding layer and located above the upper conductive layer; a redistribution layer mounted on the molding layer and electrically connected to the first surface of the die and the upper conductive layer; wherein the molding layer is formed by laminating a first insulating sheet and a second insulating sheet.