Stacked PCB Assembly for Lower Ball Count and Smaller Packages
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Solution Overview
Problem
The increasing miniaturization of components and higher packaging density of integrated circuits lead to larger overall package sizes, posing a challenge for PCB designers due to the flat structure of PCBs, which restricts the shape of electronic devices.
Innovation Solution
The solution involves an electronic device with stacked printed circuit boards (PCBs), where a main PCB assembly includes a bottom PCB with a semiconductor package mounted on its upper surface. This semiconductor package features a substrate with a semiconductor die encapsulated by a molding compound, and a top PCB is connected through connecting elements, optionally with a middle re-distribution layer (RDL) structure and a memory component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If more signal balls are integrated into one single chip package to support higher functionality and performance, then the overall package size increases
Solution Approach 1:
The patent transitions from a two-dimensional planar PCB layout to a three-dimensional stacked configuration with multiple PCB layers connected vertically through via structures. This dimensional change allows signal balls and electronic components to be distributed across multiple levels, increasing functionality without proportionally increasing the footprint area, thereby resolving the contradiction between adaptability and package volume.
Solution Approach 2:
The patent implements nested structures where smaller PCB layers are positioned within the vertical projection of larger lower layers, and via structures penetrate through multiple layers to create compact nested pathways. This nesting approach allows multiple signal balls and components to be packed into a smaller overall volume while maintaining electrical connectivity, addressing the contradiction between functionality and package size.
2Ease of manufacture
If PCBs maintain a flat structure for component fixation, then the shape of the electronic device is constrained
Solution Approach 1:
The patent introduces vertical stacking of multiple PCB layers connected by via structures, transforming the traditionally flat two-dimensional PCB into a three-dimensional assembly. This enables the electronic device to achieve complex shapes and compact form factors while maintaining the flat PCB structure for ease of component fixation on each individual layer.
Solution Approach 2:
The patent divides the PCB into multiple separate layers that can be manufactured and populated with components independently using conventional flat PCB techniques. These segmented layers are then assembled vertically with via connections, allowing each layer to maintain its flat structure for ease of manufacture while the overall device achieves a compact three-dimensional shape.
Data Source
AI summary
An electronic device includes a main printed circuit board (PCB) assembly comprising a bottom PCB and a semiconductor package mounted on an upper surface of the bottom PCB. The semiconductor package includes a substrate and a semiconductor die mounted on a top surface of the substrate. The semiconductor die and the top surface of the substrate are encapsulated by a molding compound. A top PCB is mounted on the semiconductor package through first connecting elements.