Semiconductor Package Conductive Posts Prevent Solder Bridging
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Solution Overview
Problem
Conventional package-on-package (PoP) structures face challenges with increased I/O density, as reduced solder ball pitch leads to solder bridging due to increased density, which affects processing performance and substrate area efficiency.
Innovation Solution
The method involves using conductive posts to electrically connect upper and lower substrates, with an encapsulant formed between them, and removing the upper substrate to prevent solder bridging, allowing for finer pitches without consuming excessive space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solder ball pitch is reduced to increase I/O density, then more I/O connections can be achieved in the same package area, but solder bridging occurs between adjacent solder balls
Solution Approach 1:
The patent extracts the substrate (first substrate) from the final package structure. By using a temporary substrate during fabrication that is removed afterward, the design eliminates the need for solder balls on the final package, replacing them with conductive posts that extend through the encapsulant, thereby preventing solder bridging while maintaining high I/O density
Solution Approach 2:
The patent segments the fabrication process into stages using a temporary first substrate that is removed after bonding. This segmentation allows the conductive posts to be formed and bonded on the temporary substrate, then the substrate is removed and the package is completed with the encapsulant, separating the bonding function from the final package structure
2Quantity of substance
If conventional solder balls are used for interconnection, then electrical connection between substrates is achieved, but excessive space is consumed limiting I/O density
Solution Approach 1:
The patent removes the temporary first substrate after bonding the second substrate to it. This extraction eliminates the need for large solder balls, allowing the use of smaller conductive posts that extend through the encapsulant, thereby reducing the area consumed per I/O connection and increasing overall I/O density
Solution Approach 2:
The patent transitions from planar solder ball connections to three-dimensional conductive posts that extend vertically through the encapsulant. This dimensional change allows connections to be made in the vertical dimension rather than requiring lateral space, thereby increasing I/O density without increasing package area
Data Source
AI summary
A method for fabricating a semiconductor package is provided, which includes the steps of: providing a first substrate having a plurality of first conductive posts on a surface thereof and providing a second substrate having a third surface having a chip disposed thereon and a fourth surface opposite to the third surface; disposing the first substrate on the third surface of the second substrate through the first conductive posts; forming an encapsulant between the first substrate and the second substrate, wherein the encapsulant has a first surface adjacent to the first substrate and a second surface opposite to the first surface; and removing the first substrate, thereby effectively preventing solder bridging from occurring.