Bulk Acoustic Resonator Heat-Dissipation Structure for EMI Shielding
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Solution Overview
Problem
Bulk acoustic resonators lack effective heat dissipation and electromagnetic shielding, leading to performance issues and reliability concerns in high-frequency wireless communication devices.
Innovation Solution
A bulk acoustic resonator design incorporating a metal heat dissipation layer with an insulating layer on a substrate, along with a resonance function layer and an electromagnetic shielding structure, to enhance heat dissipation and reduce parasitic capacitance while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional substrate or support layer (Si or Si3N4) is used for the bulk acoustic resonator, then the device can be manufactured with existing processes, but the heat dissipation effect is poor and reliability is low
Solution Approach 1:
The patent changes the material parameter of the substrate from conventional Si or Si3N4 to a metal substrate with high thermal conductivity. This parameter change enables effective heat dissipation while maintaining manufacturability through adapted fabrication processes including metal substrate preparation, insulating layer deposition, and resonator structure formation.
Solution Approach 2:
The patent employs a composite structure combining metal substrate, insulating layer, and piezoelectric layer with electrodes. This composite material approach allows the metal substrate to provide heat dissipation while the insulating layer prevents electrical shorting and the piezoelectric layer enables acoustic resonance function, resolving the contradiction between heat dissipation and functional performance.
2Reliability
If the bottom electrode layer is arranged on the metal heat dissipation layer, then capacitance is formed which affects resonator performance, but the heat dissipation path is blocked
Solution Approach 1:
The patent introduces an insulating layer as an intermediary between the metal heat dissipation layer and the bottom electrode layer. This insulating layer allows thermal conduction while preventing electrical capacitance formation, thus enabling heat dissipation without affecting resonator performance. The insulating layer acts as a mediator that separates the thermal and electrical pathways.
3Object-affected harmful factors
If no electromagnetic shielding structure is added, then the device complexity is low, but electromagnetic interference affects the use effect of components
Solution Approach 1:
The patent makes the metal substrate serve multiple functions: it acts as both the heat dissipation path and the electromagnetic shielding layer. The inherent electrical conductivity and physical continuity of the metal substrate provide electromagnetic shielding without requiring additional shielding structures, thus reducing device complexity while protecting against electromagnetic interference.
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
The design effectively dissipates heat and shields electromagnetic interference, improving the reliability and performance of the resonator by minimizing stress and parasitic effects, thus supporting stable operation in crowded frequency bands.
Implementation Method 1
a metal heat dissipation layer formed on the substrate... The metal heat dissipation layer confers a heat dissipation effect on the bulk acoustic resonator
Implementation Method 2
provided with an insulating layer on its surface... the metal heat dissipation layer and the insulating layer define a cavity on the substrate
Implementation Method 3
The piezoelectric layer can realize the conversion between electrical energy and mechanical energy. When an electric field is applied to the upper and lower electrodes of the Fbar, the piezoelectric layer generates mechanical energy in the form of sound waves
Implementation Method 4
a resonance function layer formed on the insulating layer... The resonance function layer converts electrical energy into mechanical energy, and produces a resonance effect in the form of sound waves
Data Source
AI summary
A bulk acoustic resonator having a heat dissipation structure, and a fabrication process are provided according to the present application. The bulk acoustic resonator includes a substrate, a metal heat dissipation layer formed on the base substrate and provided with an insulating layer on the surface thereof, and a resonance functional layer formed on the insulating layer, where the metal heat dissipation layer and the insulating layer together define a cavity on the substrate, a side wall of the cavity is formed by the insulating layer, and a bottom electrode layer in the resonance function layer covers the cavity.