RF Filter Fan-Out Substrate With Embedded Passives for Smaller Modules
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Solution Overview
Problem
There is a desire to reduce the size of packaged modules, particularly those containing radio-frequency (RF) filters such as acoustic wave devices, while maintaining or improving their performance and reliability.
Innovation Solution
The integration of passive elements, such as inductors, capacitors, or resistors, within redistribution layers of a packaging substrate, combined with a mold structure that encapsulates the RF die, allows for a reduced footprint and improved performance by providing a fan out circuit and matching functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If passive elements are integrated within redistribution layers and mold structure encapsulates the RF die, then lateral dimensions are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent combines multiple functions into the redistribution layers: signal routing, passive element implementation (inductors, capacitors, resistors), and RF matching functionality. The mold structure is integrated to provide both encapsulation and structural support, reducing the need for separate components and thereby reducing lateral dimensions despite increased manufacturing complexity
Solution Approach 2:
The patent utilizes vertical stacking and three-dimensional integration within the substrate to accommodate passive elements and RF circuits. By moving functionality from a planar layout to a multi-layer vertical architecture, the lateral footprint is reduced while maintaining all necessary circuit functions
2Device complexity
If passive elements are implemented as printed features on redistribution layers, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements passive elements by printing conductive features directly onto redistribution layers, changing the form factor from discrete components to integrated printed patterns. This approach simplifies device architecture but requires precise control of printing parameters, material deposition thickness, and pattern alignment to achieve desired electrical characteristics
Data Source
AI summary
A packaged module can include a substrate having first and second sides, and a plurality of redistribution layers. The packaged module can further include a filter die implemented on the first side of the substrate, and a plurality of pins implemented on the second side of the substrate, such that the redistribution layers include a fan out circuit between the filter die and the pins. The packaged module can further include a passive element implemented as part of the redistribution layers and configured to support operation of the filter die.