Backside Via FBAR Heat Dissipation
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Solution Overview
Problem
There is a need to reduce the footprint and improve heat dissipation of Bulk Acoustic Wave (BAW) resonators, particularly Thin Film Bulk Acoustic Resonators (FBARs), as they are used in various electronic devices, to meet the demands of smaller device sizes and increased power requirements.
Innovation Solution
The design incorporates a via structure that is thermally and electrically connected directly beneath the FBAR, reducing the device's footprint and enhancing heat dissipation by using a thermally conductive material, such as molybdenum or copper, to provide a shorter electrical path and improve thermal energy dissipation to a thermal sink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional top-side via structures are used, then electrical connections are established, but the device footprint is larger and heat dissipation is less effective
Solution Approach 1:
The patent inverts the traditional via placement by moving it from the top side to the backside of the substrate. This inversion allows the via to be positioned directly beneath the FBAR, achieving both footprint reduction and improved heat dissipation through direct thermal coupling with the heat source.
Solution Approach 2:
The patent introduces a thermally conductive material (such as diamond-like carbon or metal) as an intermediary between the FBAR and the backside via. This intermediary enhances heat transfer from the FBAR through the substrate to the via, which then conducts heat to the thermal sink, solving the heat dissipation problem while maintaining compact dimensions.
2Productivity
If FBAR size is reduced to meet miniaturization demands, then device integration increases, but heat dissipation capability deteriorates
Solution Approach 1:
The patent transitions from planar heat dissipation to three-dimensional heat management by extending the thermal conduction path vertically through the substrate. The backside via penetrates through the substrate thickness, creating a direct thermal pathway from the FBAR through the substrate to the external thermal sink, enabling effective heat dissipation in miniaturized devices.
Solution Approach 2:
The patent employs composite material structures including thermally conductive coatings (such as diamond-like carbon) on the substrate and metal fill materials in the backside via. These composite materials provide enhanced thermal conductivity along the heat flow path, maintaining heat dissipation capability despite reduced device dimensions and improved integration density.
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 configuration reduces the overall area required for FBARs by 15% to 19% compared to traditional top-side via structures, while providing effective thermal and electrical paths, thereby enhancing the reliability and performance of FBARs under increased power demands.
Implementation Method 1
enhancing heat dissipation by using a thermally conductive material, such as molybdenum or copper, to provide a shorter electrical path and improve thermal energy dissipation to a thermal sink
Implementation Method 2
Acoustic transducers, in particular, convert electrical signals to acoustic signals (sound waves) and convert received acoustic waves to electrical signals via inverse and direct piezoelectric effect
Data Source
AI summary
An film bulk acoustic wave resonator (FBAR) structure has an FBAR and a via disposed substantially directly beneath the FBAR. The via is in thermal contact with the FBAR. A plurality of vias may be included. The via(s) serve to dissipate heat generated by the FBAR structure during operation.