Package-on-Package Module Height Reduction via Resin Interlayer
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Solution Overview
Problem
In package-on-package structures with redistribution layers, achieving flatness and reducing height is challenging due to the thin film nature of the redistribution layer, necessitating the use of bumps for stacking, which complicates the manufacturing process and increases costs.
Innovation Solution
A module configuration that includes a substrate with a first component, a sealing resin layer, a second component mounted on the opposite surface, and an intermediate layer with columnar conductors connecting the components to a redistribution layer, allowing for stacking without bumps, and using a frame-shaped substrate with a cavity and grooves to improve heat dissipation and prevent warping, while eliminating the need for additional conductors and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a thin film redistribution layer is used to enable fan-out type module and POP structure, then the module can be made thinner and accommodate miniaturization of components, but it becomes difficult to achieve flatness of the upper surface, necessitating the use of bumps that increase the module height
Solution Approach 1:
A resin layer is introduced as an intermediary substance between the uneven upper surface of the redistribution layer and the component to be mounted. This resin layer fills in the irregularities and provides a flat mounting surface, allowing the module to maintain thin profile without requiring additional height-increasing bumps for surface flattening.
Solution Approach 2:
The invention changes the physical state and properties of the resin material to achieve surface flattening. By selecting resin with appropriate viscosity, curing characteristics, and fill properties, the uneven surface is transformed into a flat mounting surface through material property optimization rather than structural additions.
2Reliability
If bumps are used to connect stacked modules in POP structure, then electrical connectivity between layers is achieved, but the manufacturing process becomes more complex and costs increase
Solution Approach 1:
The invention extracts and eliminates the bump formation process from the manufacturing sequence. By using a resin layer that provides both mechanical support and electrical connectivity during the lamination process, the complex multi-step bump formation and reflow process is replaced with a simpler single-step lamination operation.
Solution Approach 2:
The invention merges multiple functions into the resin layer: it provides surface flattening, mechanical support, and electrical connectivity simultaneously. This consolidation of functions into a single material layer simplifies the overall manufacturing process compared to using separate components for each function.
3Temperature
If additional conductors are added to improve heat dissipation in POP structure, then thermal management is enhanced, but the device complexity and manufacturing costs increase
Solution Approach 1:
The resin layer is designed to perform multiple functions simultaneously: it flattens the surface, provides mechanical support, enables electrical connectivity, and dissipates heat. This multi-functionality eliminates the need for separate thermal management structures, maintaining device simplicity while achieving effective heat dissipation.
Solution Approach 2:
The invention uses composite resin materials that combine electrical insulating properties with thermal conducting properties. By selecting resin formulations that incorporate thermally conductive fillers, the material simultaneously provides electrical isolation and enhanced heat dissipation without requiring additional conductor structures.
Data Source
AI summary
Provided is a module which has a package-on-package structure including a redistribution layer and can be easily reduced in height. A module 1 includes an upper module including a substrate, a first component, and a sealing resin layer, and a lower module including an intermediate layer and a redistribution layer. The first component is connected to the redistribution layer with a columnar conductor interposed therebetween and provided in the intermediate layer, and both the first component and a second component are rewired by the redistribution layer. Since the intermediate layer is formed by using a frame-shaped substrate, the upper module and the lower module can be connected without necessarily a bump, so that it is possible to provide a module which has a fanout-type package-on-package structure and can be easily reduced in height.