Molded Silicon-on-Passive Package for Ultra-Thin SiP Stacking
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Solution Overview
Problem
Current microelectronic packaging technologies face challenges in miniaturization and thickness reduction for systems in packages (SiPs) with stacked active devices and passive components, as they rely on conventional substrates and molding processes that limit the integration density and overall package form factor.
Innovation Solution
The proposed solution involves a manufacturing sequence where passive components are mounted on a patterned lead frame, followed by the integration of known good dies, and then encapsulated in a molding compound layer, with the lead frame being partially consumed to create thin terminal pads and a planarized surface, allowing for reduced package thickness and area, and enabling additional routing options through pre-formed substrates or molded interconnect substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional substrates and molding processes are used for SiPs with stacked active devices and passive components, then the package can be assembled with standard processes, but the package thickness and area cannot be sufficiently reduced
Solution Approach 1:
The patent transitions from conventional planar substrate mounting to a vertical stacked architecture where passive components are mounted on the lead frame before die attachment, enabling three-dimensional integration that reduces package footprint and thickness while maintaining manufacturing feasibility through standardized processes
Solution Approach 2:
Passive components are pre-mounted on the lead frame in a preliminary assembly step before the die is attached and before final molding. This preliminary action allows for optimized space utilization and enables subsequent thinning operations to achieve reduced package thickness
2Length of moving object
If the lead frame is partially consumed to create thin terminal pads, then terminal pad thickness can be reduced to less than 75 μm, but the manufacturing process becomes more complex
Solution Approach 1:
The lead frame undergoes parameter changes through selective removal processes that transform it from a conventional thick substrate into thin terminal pads with controlled thickness of less than 75 μm. This parameter change enables ultra-thin pad profiles while maintaining structural integrity through controlled consumption of the lead frame material
Solution Approach 2:
The patent creates a copied or replicated lead frame structure where the original lead frame serves as a sacrificial template that is partially removed to create the final thin pad structure. This copying approach allows precise control over the final pad geometry and thickness
3Quantity of substance
If passive components and dies are stacked vertically, then integration density increases and package area is reduced, but alignment precision requirements increase
Solution Approach 1:
The vertical stack is segmented into distinct functional layers: lead frame with passive components, die, and molding compound. This segmentation allows each layer to be independently fabricated and then precisely aligned during assembly, reducing the overall alignment precision requirements compared to a monolithic structure while maintaining high integration density
Data Source
AI summary
Package structures, modules containing such packages and methods of manufacture. are described. In an embodiment, a package includes a plurality of terminal pads, a plurality of passive components bonded to top sides of the plurality of terminal pads, a die bonded to top sides of the plurality of passive components and a molding compound encapsulating at least the plurality of passive components and the die.