Cavity PCB for PoP Gap Maintenance
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Solution Overview
Problem
In semiconductor packages with a PoP structure, reducing ball pitch to increase I/Os makes it difficult to maintain a sufficient gap between upper and lower packages, leading to increased manufacturing costs due to discarded IC chips during the manufacturing process.
Innovation Solution
A printed circuit board with a cavity of predetermined depth in its base substrate, where an electronic component is mounted, allowing for a gap between upper and lower semiconductor packages even with decreased ball pitches, featuring pads exposed through the cavity bottom surface and vias for electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ball pitch is reduced to increase the number of I/Os, then the number of inputs/outputs increases, but the gap between upper and lower semiconductor packages becomes insufficient
Solution Approach 1:
The invention transitions from a flat PCB surface to a three-dimensional structure by forming a cavity (凹陷部) in the PCB. This allows the lower semiconductor package to be positioned lower than the PCB surface, creating vertical space that increases the gap between upper and lower packages without requiring larger ball pitch, thus enabling high I/O count while maintaining sufficient package spacing.
2Length of stationary object
If IC chips are embedded in PCB to create gap space, then gap between packages is obtained, but manufacturing cost increases due to discarded failed boards
Solution Approach 1:
The invention replaces expensive IC chips with a simple cavity structure formed directly in the PCB. The cavity is created through conventional PCB manufacturing processes (etching, drilling, plating) without requiring additional expensive components. This eliminates the risk of costly board discards associated with embedded IC chips while still achieving the desired gap space.
3Length of stationary object
If cavity depth is increased to mount electronic components, then gap between packages increases, but manufacturing complexity increases
Solution Approach 1:
The invention optimizes the cavity dimensions (depth, width, shape) to achieve the required gap space while maintaining manufacturability. By carefully controlling the cavity depth to accommodate the lower package height and positioning the pad at an appropriate level, the design achieves sufficient package spacing without creating excessively complex structures that would be difficult or costly to manufacture.
Data Source
AI summary
Disclosed herein are a printed circuit board, a manufacturing method thereof, and a semiconductor package including the printed circuit board. The printed circuit board includes a base substrate including a plurality of circuit patterns, a cavity formed above the base substrate, a pad embedded in the base substrate and being exposed through the substrate bottom surface of the cavity, and an electronic component mounted in the cavity and electrically connected to the pad.According to the present invention, a cavity having a predetermined depth is formed in a base substrate of a printed circuit board so as to mount an electronic component therein, such that a gap between an upper semiconductor package and a lower semiconductor package may be obtained even if pitches between the balls are decreased for high density and high performance of the upper semiconductor package in the manufacturing of a semiconductor package having a PoP structure.