InFO Antennas and Waveguides for High-Frequency Integration
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Solution Overview
Problem
The performance of passive devices such as antennas and waveguides in RF applications is hindered by low Q factors due to Eddy currents in silicon substrates, and existing solutions on glass substrates or in fan-out structures do not meet satisfactory results.
Innovation Solution
The formation of packages including antennas or waveguides in Integrated Fan-Out (InFO) structures involves specific steps like forming a carrier, dielectric layers, redistribution lines, metal features, and encapsulating materials, with a focus on low-loss dielectric materials and redistribution lines to enhance signal coupling and reduce losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If passive devices are formed on silicon substrates, then integration with active devices is achieved, but Q factor deteriorates due to Eddy currents
Solution Approach 1:
The patent introduces an intermediary structure (passive device formed on a separate substrate or in a fan-out region) that mediates between the silicon substrate and the RF signal path. This intermediary approach allows the passive device to be electrically isolated from the silicon substrate, preventing Eddy current losses while maintaining integration benefits through controlled connections.
2Reliability
If passive devices are formed on glass substrates or in fan-out structures, then Q factor is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the formation of passive devices with the existing fan-out interconnect structure. By integrating passive device fabrication into the established fan-out process flow, the solution achieves high Q factor performance without significantly increasing manufacturing complexity, as both structures are formed using similar material deposition and patterning techniques.
3Device complexity
If conventional antenna structures are used, then design simplicity is maintained, but performance at frequencies above 50 GHz deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the geometric dimensions, material composition, and structural configuration of the antenna to achieve optimal performance at frequencies above 50 GHz. This includes adjusting the antenna size, shape, and surrounding dielectric environment to minimize losses and maximize radiation efficiency at millimeter-wave frequencies.
Data Source
AI summary
A method includes forming a first metal plate, forming a metal ring aligned to peripheral regions of the first metal plate, and placing a device die level with the metal ring, encapsulating the device die and the metal ring in an encapsulating material. The method further includes filling a dielectric material into a space encircled by the metal ring, and forming a second metal plate covering the dielectric material and the metal ring, with an opening formed in the second metal plate. A plurality of redistribution lines is formed, with one of the redistribution lines overlapping a portion of the opening. The first metal plate, the metal ring, the second metal plate, and the dielectric material in combination form an antenna or a waveguide. The redistribution line forms a signal-coupling line of the passive device.