Redistribution Structure Dummy Metal Layout for Package Warpage
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Solution Overview
Problem
As semiconductor devices integrate more dies to achieve high levels of integration, warpage becomes a significant issue due to differences in thermal expansion coefficients of various materials, leading to stress and potential delamination, especially in interface and perimeter regions, which affects bonding yield and structural integrity.
Innovation Solution
Incorporating dummy metal patterns in the redistribution structure, which can be island-shaped, mesh-shaped, or strip-shaped, to reduce warpage by dissipating heat, providing electromagnetic interference shielding, and achieving uniform metal density, thereby reducing stress and improving structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple dies are integrated into a stacked semiconductor structure, then integration density is improved, but warpage and stress increase due to differences in thermal expansion coefficients
Solution Approach 1:
The patent applies local quality by placing dummy metal patterns specifically in interface regions and perimeter areas where warpage and stress are most severe. These dummy metals are strategically positioned at boundaries between different dies and in regions with high thermal expansion coefficient differences, providing localized stress compensation rather than uniformly distributing metals throughout the entire structure.
Solution Approach 2:
The patent employs composite materials by combining dummy metal patterns with the existing redistribution structure and die stack. The dummy metals form a composite system with the interposer and surrounding materials, creating a multi-material structure that balances thermal expansion coefficients and reduces overall warpage while maintaining the functional integrity of the stacked semiconductor device.
2Stability of the object's composition
If dummy metal patterns are added to the redistribution structure, then warpage is reduced, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the dummy metal configuration into distinct types (island-shaped, mesh-shaped, strip-shaped) and positioning them in specific regions (interface regions, perimeter regions). This segmented approach allows targeted stress management in different areas without requiring a complete redesign of the entire redistribution structure, thereby limiting the increase in complexity to only the necessary locations.
3Reliability
If dummy metal patterns are used to reduce warpage, then manufacturing cost increases, but bonding yield improves
Solution Approach 1:
The patent applies partial action by implementing dummy metal patterns only in critical regions where warpage most significantly impacts bonding yield, specifically at interface regions between dies and in perimeter regions. This selective placement provides sufficient stress compensation to improve bonding yield without the need to populate the entire redistribution structure with dummy metals, thereby controlling manufacturing costs while achieving the reliability improvement.
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 use of dummy metal patterns effectively reduces warpage, enhances bonding yield, and prevents delamination during the dicing process, ensuring improved planarity and structural integrity of semiconductor devices.
Implementation Method 1
Incorporating dummy metal patterns in the redistribution structure, which can be island-shaped, mesh-shaped, or strip-shaped, to reduce warpage by dissipating heat
Implementation Method 2
Incorporating dummy metal patterns in the redistribution structure, which can be island-shaped, mesh-shaped, or strip-shaped, to reduce warpage by dissipating heat, providing electromagnetic interference shielding, and achieving uniform metal density
Data Source
AI summary
A semiconductor device includes: a substrate; a plurality of dies attached to a first side of the substrate; a molding material on the first side of the substrate around the plurality of dies; a first redistribution structure on a second side of the substrate opposing the first side, where the first redistribution structure includes dielectric layers and conductive features in the dielectric layers, where the conductive features include conductive lines, vias, and dummy metal patterns isolated from the conductive lines and the vias; and conductive connectors attached to a first surface of the first redistribution structure facing away from the substrate.