Semiconductor Package Conductive Posts for Wiring Flexibility
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Solution Overview
Problem
Existing semiconductor package structures face limitations in design flexibility and increased fabrication costs due to the need for wire bonding pads and solder ball pads on substrates, which restrict the electrical connecting area and wiring density, leading to waste of known good dies and reduced operational efficiency.
Innovation Solution
A package structure with a substrate having conductive pads and posts, where first and second conductive bumps are formed, allowing for increased electrical connectivity without area limitations, with the second bumps being higher than the first, enabling flexible electronic element stacking and reduced package height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding pads and solder ball pads are formed on the substrate to electrically connect semiconductor chips and packages, then electrical connectivity is achieved, but the wiring area is limited and fabrication cost increases
Solution Approach 1:
The patent transitions from planar wiring on the substrate surface to three-dimensional conductive posts extending vertically through the substrate. This dimensional change allows electrical connections to be made in the vertical direction rather than requiring extensive lateral wiring space, thereby resolving the contradiction between achieving electrical connectivity and limiting wiring area.
Solution Approach 2:
The conductive posts serve multiple functions: they provide electrical connectivity between different layers, act as mechanical support structures, and enable both wire bonding and solder ball connections. This multi-functionality eliminates the need for separate dedicated wiring areas, thus resolving the contradiction between electrical connectivity and wiring area limitation.
2Reliability
If wire bonding pads and solder ball pads are formed on the substrate, then electrical connectivity is achieved, but fabrication cost increases due to required built-up substrate technologies
Solution Approach 1:
The conductive posts are pre-formed within the substrate during substrate fabrication, before any packaging or wiring operations. This preliminary action eliminates the need for subsequent expensive built-up substrate processes, thereby resolving the contradiction between achieving electrical connectivity and controlling fabrication cost.
Solution Approach 2:
The patent extracts the electrical connection function from the substrate surface wiring and relocates it to vertically extending conductive posts. This separation allows the substrate to be simpler and less expensive, while still achieving the required electrical connectivity, thus resolving the contradiction between electrical connectivity and fabrication cost.
3Reliability
If solder balls are bonded outside the chip mounting area to connect upper and lower semiconductor packages, then electrical connectivity between packages is achieved, but the electrically connecting area and I/O count are limited
Solution Approach 1:
The patent enables electrical connections to extend vertically through the substrate via conductive posts, allowing upper and lower packages to be connected in the vertical dimension rather than being constrained to the horizontal chip mounting area. This resolves the contradiction between achieving package electrical connectivity and maintaining design flexibility.
Solution Approach 2:
The conductive posts provide flexible routing paths that can accommodate different I/O configurations and package arrangements. The vertical connection paths can be dynamically configured to support various design requirements, thereby resolving the contradiction between package electrical connectivity and design flexibility.
4Productivity
If multiple semiconductor packages are stacked to increase I/O count, then connectivity capacity is improved, but the package height increases
Solution Approach 1:
The patent implements a nested structure where multiple conductive posts are integrated within the substrate thickness, allowing vertical electrical connections to be embedded within the substrate rather than extending outward. This nesting approach enables increased I/O capacity through stacking while minimizing the increase in overall package height.
Data Source
AI summary
A package structure is provided, which includes: a substrate having opposite top and bottom surfaces and a plurality of conductive pads and a plurality of conductive posts formed therein, wherein the conductive pads are exposed from the bottom surface of the substrate, and the conductive posts are electrically connected to the conductive pads and each of the conductive posts has an end surface exposed from the top surface of the substrate; a plurality of first conductive bumps formed on the end surfaces of the conductive posts; a plurality of second conductive bumps formed on the top surface of the substrate, wherein the second conductive bumps are higher than the first conductive bumps; and at least a first electronic element disposed on and electrically connected to the first conductive bumps, thereby increasing the wiring flexibility and facilitating subsequent disposing of electronic elements without changing existing machines.