Semiconductor Package Bump Layout for Underfill Flow Resistance
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Solution Overview
Problem
In semiconductor packaging, the flow of underfill material can alter the shape of reflow solder, leading to deteriorated electrical characteristics, particularly when dummy bumps are absent, as they provide resistance to underfill flow and maintain solder shape.
Innovation Solution
Incorporating second bumps that are electrically insulated from through-electrodes and arranged in a specific pattern with first bumps, these bumps resist the flow of underfill, maintaining the shape and electrical characteristics of reflow solder by distributing pressure evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If dummy bumps are absent in the semiconductor package, then the device complexity is reduced, but the reflow solder shape deteriorates due to unresisted underfill flow
Solution Approach 1:
The patent introduces a non-conductive underfill material as an intermediary substance between the substrate and the reflow solder. This underfill material fills the gap and provides resistance to underfill flow, thereby maintaining the reflow solder shape without requiring dummy bumps. The underfill acts as a mediator that resolves the contradiction by providing the necessary structural support while avoiding the complexity of additional bump structures.
2Ease of operation
If underfill material flows freely without resistance, then the ease of operation is improved, but the electrical characteristics deteriorate due to altered solder shape
Solution Approach 1:
The patent applies preliminary anti-action by introducing the non-conductive underfill material before the underfill flow occurs. This underfill material pre-establishes resistance to the underfill flow, preventing the flow from altering the reflow solder shape. By acting in advance, the underfill material ensures that the electrical characteristics are maintained while still allowing controlled underfill operation.
3Manufacturing precision
If second bumps are added to resist underfill flow, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The patent changes the parameter of the underfill material by making it non-conductive, which fundamentally alters its properties and enables it to provide resistance to underfill flow without requiring additional structural elements like second bumps. This parameter change in the material property resolves the contradiction by achieving the desired solder shape maintenance while avoiding increased structural complexity.
Data Source
AI summary
A semiconductor package includes a substrate, through-electrodes penetrating the substrate, first bumps spaced apart from each other in a first direction parallel to a top surface of the substrate and electrically connected to the through-electrodes, respectively, and at least one second bump disposed between the first bumps and electrically insulated from the through-electrodes. The first bumps and the at least one second bump constitute one row in the first direction. A level of a bottom surface of the at least one second bump from the top surface of the substrate is a substantially same as levels of bottom surfaces of the first bumps from the top surface of the substrate.