LGA Interface Layer for Passive-on-Glass Packaging
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Solution Overview
Problem
Conventional semiconductor packaging using Ball Grid Arrays (BGAs) results in variable ball height and spacing between passive components and the ground plane of a Printed Circuit Board (PCB), which depends on the PCB technology, affecting the performance of passive components like inductors and capacitors.
Innovation Solution
A Passive-on-Glass (POG) structure with an interface layer that includes Land Grid Array (LGA) pads and vias, allowing for controlled electrical connection between contact pads and LGA pads, maintaining a consistent distance between the passive component and the ground plane independent of PCB line spacing or layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ball Grid Array (BGA) is used to attach POG structure to PCB, then electrical connection is achieved, but ball height varies depending on PCB line spacing affecting passive component performance
Solution Approach 1:
The patent introduces an interface layer as an intermediary between the POG structure and PCB. This interface layer includes LGA pads that provide a standardized interface, decoupling the passive component distance from PCB line spacing variations. The interface layer acts as a mediator that absorbs the variability in PCB technologies while maintaining consistent electrical and mechanical connections.
Solution Approach 2:
The patent segments the connection system into distinct functional layers: the POG structure layer, the interface layer with LGA pads, and the PCB layer. This segmentation allows each layer to be optimized independently - the interface layer can be designed with fixed thickness to control passive component distance, while the PCB can use various line spacing without affecting the POG structure performance.
2Productivity
If PCB line spacing is reduced, then PCB integration density is improved, but ball height increases affecting the distance between passive component and ground plane
Solution Approach 1:
The interface layer serves as a buffer that decouples the relationship between PCB line spacing and passive component distance. By introducing this intermediary layer with controlled thickness, the system can use smaller PCB line spacing for higher integration density without compromising the required distance between passive components and ground plane.
3Adaptability or versatility
If different PCB technologies are used, then design flexibility is improved, but ball height and passive component spacing become unpredictable
Solution Approach 1:
The interface layer with LGA pads provides a universal interface that works with different PCB technologies. The standardized LGA pad design allows the same POG structure to be mounted on various PCBs with different line spacing and layer configurations, maintaining consistent electrical and mechanical performance across different PCB platforms.
Data Source
AI summary
A device includes a passive-on-glass (POG) structure and an interface layer. The POG structure includes a passive component and at least one contact pad on a first surface of a glass substrate. The interface layer has a second surface on the first surface of the glass substrate such that the passive component and the at least one contact pad are located between the first surface of the glass substrate and the interface layer. The interface layer includes at least one land grid array (LGA) pad formed on a third surface of the interface layer, where the third surface of the interface layer is opposite the second surface of the interface layer. The interface layer also includes at least one via formed in the interface layer configured to electrically connect the at least one contact pad with the at least one LGA pad.