Semiconductor Package Dummy Patterns for Warpage Control
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Solution Overview
Problem
Fan-out semiconductor packages experience warpage due to differences in thermal expansion coefficients between components, particularly in the corner regions, leading to bending issues when heated.
Innovation Solution
Incorporating dummy patterns in the corner regions of the semiconductor package, which are made of the same material as the redistribution wiring layers, to increase the thermal expansion coefficient and act as reinforcing patterns, thereby preventing warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the package uses a thin frame structure with redistribution wiring layers, then the total package thickness is reduced, but corner portions roll up when heated causing smile warpage
Solution Approach 1:
The patent applies local quality by placing dummy patterns specifically at the corner portions of the package where warpage occurs. These dummy patterns are made of the same material as the redistribution wiring layers and have the same thickness, creating localized reinforcement only where needed rather than uniformly across the entire package structure.
Solution Approach 2:
The patent utilizes thermal expansion by designing dummy patterns with the same thermal expansion characteristics as the redistribution wiring layers. When heated, these dummy patterns expand at the same rate as the surrounding wiring layers, compensating for differential thermal expansion and preventing the corner portions from rolling up.
2Stability of the object's composition
If dummy patterns are added to corner regions, then warpage is prevented through increased thermal expansion coefficient, but the package structure becomes more complex
Solution Approach 1:
The patent applies homogeneity by making the dummy patterns identical in material composition and thickness to the redistribution wiring layers. This uniformity simplifies the manufacturing process as the dummy patterns can be formed using the same processes and materials as the existing wiring layers, despite adding structural elements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The dummy patterns effectively compensate for the thermal expansion differences, reducing the likelihood of warpage and enhancing the structural integrity of the package, especially in high-temperature conditions.
Implementation Method 1
due to a difference in coefficient of thermal expansion between individual components of the package, corner portions of a peripheral region of the package that is relatively weak may be rolled up when it is heated
Data Source
AI summary
A semiconductor package includes a substrate, at least one semiconductor chip arranged in the substrate and having chip pads, and a redistribution wiring layer covering a lower surface of the substrate and including first and second redistribution wirings and dummy patterns, the first and second redistribution wirings being stacked in at least two levels and connected to the chip pads. The first and second redistribution wirings are arranged in a redistribution region of the redistribution wiring layer, and the dummy patterns extend in an outer region outside the redistribution region to partially cover corner portions of the redistribution wiring layer, respectively.