Ultra Thin Package Stiffener for Bending and Heat
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Solution Overview
Problem
Thin, flexible substrates in electronic component packages are prone to undesirable bending, leading to electrical interconnection failures and premature failure due to heat buildup.
Innovation Solution
A stiffener is integrated into the package, featuring via apertures with electrically conductive sidewalls and an electronic component opening, which is attached to the substrate to minimize bending and act as an internal heat sink, thereby enhancing structural rigidity and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the substrate is made thin to reduce package size, then the package height is reduced, but the substrate becomes flexible and prone to bending which leads to electrical interconnection failure
Solution Approach 1:
The substrate is designed with non-uniform thickness, being thinnest at the electronic component opening and progressively thicker toward the edges. This local variation in thickness provides structural support at the edges while maintaining a thin profile at the component area, preventing bending without increasing overall package height
Solution Approach 2:
The substrate is segmented into different thickness zones, with the thinnest region at the center for component mounting and progressively thicker regions toward the periphery for mechanical support. This segmentation allows the substrate to simultaneously achieve low profile and high reliability
2Volume of moving object
If the substrate is made thin to reduce package size, then the package height is reduced, but heat buildup occurs causing premature package failure
Solution Approach 1:
The substrate incorporates localized thermal management features including thermally conductive materials in specific regions and designed thickness variations that facilitate heat dissipation from hot spots while maintaining overall thin profile
Solution Approach 2:
The substrate uses composite materials with different thermal conductivities in different regions, combining materials that provide both mechanical support and efficient heat dissipation pathways to manage thermal buildup in the thin package structure
3Strength
If a stiffener is added to prevent bending, then structural rigidity is improved, but package height increases
Solution Approach 1:
Instead of adding a uniform stiffener across the entire substrate, the patent implements localized thickness increases only at the edges and periphery where mechanical support is needed. The central region remains thin to accommodate the electronic component, achieving rigidity enhancement without significant height increase
Solution Approach 2:
The substrate structure is segmented into thin central regions for component mounting and thicker peripheral regions for structural support, creating an integrated stiffening solution that is part of the substrate itself rather than a separate added component
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 stiffener effectively reduces undesirable bending of the package, improves the reliability of electrical interconnections, and enhances heat dissipation, thereby extending the lifespan of the electronic component package.
Implementation Method 1
The electrically conductive via aperture sidewalls are electrically connected to the terminals
Implementation Method 2
the stiffener minimizing undesirable bending of the package and acts as an internal heat sink
Data Source
AI summary
A method includes forming a substrate layer, the substrate layer including a circuit pattern having terminals and bump pads. A stiffener is formed, the stiffener including via apertures having electrically conductive via aperture sidewalls and an electronic component opening. The stiffener is attached to the substrate layer. The electrically conductive via aperture sidewalls are electrically connected to the terminals. An electronic component is mounted to the bump pads and within the electronic component opening thus minimizing the height of the package. Further, the stiffener minimizing undesirable bending of the package and acts as an internal heat sink.