Acoustic Resonator Structure With Temperature Compensation Layer
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Solution Overview
Problem
Traditional bulk acoustic wave (BAW) devices face challenges in manufacturing extremely thin films required for high-frequency operation above 3 GHz, leading to limited mass production yield and increased costs, while maintaining low loss and low temperature sensitivity.
Innovation Solution
A manufacturing method for an acoustic resonator involving a substrate with a bottom laminated structure, electrode layers, and a frequency-temperature coefficient compensation layer, allowing for the formation of relatively thick layers to achieve high-frequency operation with low temperature sensitivity, and enabling easy adjustment of resonance frequency through etching or trimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If extremely thin films are used to achieve high-frequency operation above 3 GHz, then the resonator can operate at high frequency, but the manufacturing yield decreases and cost increases
Solution Approach 1:
The patent changes the design parameter from extremely thin films to relatively thick films, fundamentally altering the operating principle. The thick film design with specific thickness ranges (e.g., piezoelectric layer thickness of several micrometers) enables high-frequency operation through different physical mechanisms, avoiding the manufacturing challenges of sub-micron thin film fabrication while maintaining or enhancing resonant frequency performance
Solution Approach 2:
The patent introduces a frequency-temperature coefficient compensation layer as an additional dimensional element in the device structure. This compensation layer, positioned above the piezoelectric layer, provides temperature compensation functionality that stabilizes the resonant frequency across temperature variations, thereby enabling reliable high-frequency operation without requiring extremely thin films that would be sensitive to manufacturing variations
2Speed
If extremely thin films are used to achieve high-frequency operation above 3 GHz, then the resonator can operate at high frequency, but the manufacturing complexity increases
Solution Approach 1:
The patent fundamentally changes the film thickness parameter from the nanometer scale to the micrometer scale, transforming the manufacturing process from requiring advanced lithography and precise thin-film deposition to using more conventional, well-established semiconductor fabrication techniques. This parameter change makes the manufacturing process significantly easier and more accessible
Solution Approach 2:
The addition of the frequency-temperature coefficient compensation layer introduces a new structural dimension that simplifies the overall manufacturing approach. Rather than achieving frequency stability through precise control of extremely thin film dimensions, the compensation layer provides a robust, easily manufacturable solution that is tolerant of typical fabrication variations
3Ease of manufacture
If traditional BAW device structure with thin films is used, then the device can be manufactured, but the temperature sensitivity remains high
Solution Approach 1:
The patent introduces a frequency-temperature coefficient compensation layer as a dedicated functional layer positioned above the piezoelectric layer. This compensation layer is specifically designed to counteract temperature-induced frequency drift, providing low temperature sensitivity without compromising manufacturability. The layer's material composition and thickness are optimized to provide the necessary temperature compensation effect
Solution Approach 2:
The patent employs composite material structures, combining the piezoelectric layer with the frequency-temperature coefficient compensation layer in a laminated configuration. This composite structure leverages the complementary properties of different materials to achieve both manufacturability and low temperature sensitivity, with the compensation layer material selected to provide the required thermal compensation characteristics
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 method enables the acoustic resonator to operate at high frequencies with wide bandwidth, low loss, and low temperature sensitivity, simplifying the manufacturing process and reducing costs by allowing for thicker layer formation and adjustable resonance frequency.
Implementation Method 1
a piezoelectric layer and a top electrode layer are formed on a side of the bottom electrode layer facing away from the substrate
Implementation Method 2
A low acoustic impedance layer and a high acoustic impedance layer laminated in sequence are formed on the side of the substrate
Implementation Method 3
A frequency-temperature coefficient compensation layer is formed on a side of the bottom electrode layer, the piezoelectric layer, and the top electrode layer facing away from the substrate
Data Source
AI summary
Discloses is an acoustic resonator and a manufacturing method thereof, which relate to the technical field of piezoelectric resonators. The manufacturing method of the acoustic resonator includes: forming a bottom laminated structure on a side of a substrate; forming a bottom electrode layer, a piezoelectric layer, and a top electrode layer on a side of the bottom laminated structure facing away from the substrate; and forming a frequency-temperature coefficient compensation layer on a side of the bottom electrode layer, the piezoelectric layer, and the top electrode layer facing away from the substrate.