RF Semiconductor Packaging With Doped Absorption Layer for EMI
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Solution Overview
Problem
Radio frequency (RF) semiconductor devices face performance issues due to undesired radiation from electrical interconnections and external sources, leading to signal degradation and electromagnetic interference, which current low-loss mold compounds fail to adequately address.
Innovation Solution
Incorporating an RF absorption layer made of doped semiconductor material with a dissipation factor greater than or equal to 0.1 in the operating frequency range, external to the active chip area, to absorb radiation and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If low-loss mold compounds are used in RF semiconductor device packaging, then RF signal propagation is maintained without significant attenuation, but undesired radiation and electromagnetic interference are not adequately suppressed
Solution Approach 1:
The patent applies local quality by implementing an RF absorption layer with high dissipating factor (≥0.1) in specific regions external to the active chip area, while maintaining low-loss mold compounds in signal propagation paths. This localized differentiation allows the high-loss material to absorb undesired radiation without significantly attenuating the RF signals that traverse through the low-loss regions.
Solution Approach 2:
The RF absorption layer acts as an intermediary element between the active chip area and the external environment. It mediates the interaction between RF signals and undesired radiation by absorbing electromagnetic energy in the peripheral regions, thereby protecting the active circuitry from electromagnetic interference while allowing signals to propagate freely through the low-loss mold compound regions.
2Object-affected harmful factors
If RF absorption layer with high dissipating factor is added to suppress undesired radiation, then electromagnetic interference is reduced, but device structure becomes more complex
Solution Approach 1:
The patent merges the RF absorption layer with the existing mold compound packaging structure. The high-loss material is integrated into the peripheral regions of the package, combining the protective function of the mold compound with the electromagnetic absorption function of the RF absorption layer, thereby reducing overall structural complexity compared to separate protective and absorptive components.
Solution Approach 2:
The patent employs composite materials by combining low-loss mold compound materials with high-loss RF absorption materials in a single packaging structure. This composite approach allows different regions of the package to have optimized properties for their specific functions: signal propagation in low-loss regions and radiation absorption in high-loss regions, achieving EMI suppression without significantly increasing structural complexity.
3Reliability
If RF absorption layer is positioned external to active chip area, then signal processing performance is maintained, but manufacturing alignment precision becomes more challenging
Solution Approach 1:
The patent segments the packaging structure into distinct functional zones: an active chip area for signal processing and peripheral regions for RF absorption. This segmentation allows the RF absorption layer to be positioned externally to the active area, maintaining signal processing performance while providing a clear manufacturing guideline for alignment - the absorption layer simply needs to cover the peripheral regions outside the active chip footprint.
Solution Approach 2:
The patent applies preliminary action by defining the RF absorption layer placement relative to the active chip area boundaries before final assembly. The absorption layer is configured to extend beyond the active chip area in predetermined directions, establishing alignment references that simplify the manufacturing process and reduce the precision requirements for positioning the absorption material relative to the active circuitry.
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
This solution effectively reduces channel-to-channel isolation and improves the robustness of RF semiconductor devices by minimizing reflections and signal attenuation, enhancing electrical performance and adaptability to various frequency ranges and device designs.
Implementation Method 1
the RF absorption layer includes a doped semiconductor material such that the dissipating factor of the RF absorption layer is equal or greater than 0.1 in the operating frequency range
Implementation Method 2
Incorporating an RF absorption layer made of doped semiconductor material with a dissipation factor greater than or equal to 0.1 in the operating frequency range, external to the active chip area, to absorb radiation and reduce interference
Data Source
AI summary
A radio frequency (RF) semiconductor device to process RF signals in an operating frequency range is provided which includes, a semiconductor chip including a first surface, a second surface opposite to the first surface and sidewalls, the semiconductor chip including an active chip area, a redistribution layer including a first side, the first side of the redistribution layer facing the first surface of the semiconductor chip, an RF absorption layer external to the active chip area, wherein the RF absorption layer includes a doped semiconductor material.