Integrated Quartz Oscillator on Active Substrate
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Solution Overview
Problem
Existing quartz oscillators face challenges in achieving high frequencies above 100 MHz due to thickness limitations, leading to increased susceptibility to stray capacitances and vibration sensitivity, which complicates their manufacturing and performance in GPS, radio, and radar systems.
Innovation Solution
Integrating quartz resonators directly with active electronics on a wafer using low-temperature bonding, allowing for miniaturization and reduced parasitic capacitances, thereby enhancing frequency capabilities and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If quartz resonators are made thin to achieve frequencies above 100 MHz, then frequency capability is improved, but mechanical strength deteriorates causing breakage during handling and mounting
Solution Approach 1:
The resonator is segmented from the bulk quartz substrate through precision dicing, creating thin individual resonator elements that can be handled and mounted without breaking while maintaining high frequency capability
Solution Approach 2:
A handle wafer serves as an intermediary carrier during the fabrication and handling process, providing mechanical support to thin resonators to prevent breakage, and is subsequently removed after mounting
2Speed
If resonator dimensions are reduced for UHF operation, then frequency capability is improved, but susceptibility to stray capacitances increases
Solution Approach 1:
The resonator is merged with active electronic circuitry on the same substrate, creating an integrated oscillator module where the electronics provide shielding and compensation that reduces the impact of stray capacitances on the small resonator
Solution Approach 2:
The packaging and mounting geometry are optimized to minimize parasitic capacitance contributions from external structures, and the resonator is positioned close to the active circuitry to reduce coupling with stray capacitive elements
3Ease of manufacture
If hybrid mounting techniques with ceramic packages are used, then ease of manufacture is improved, but device size and power consumption increase
Solution Approach 1:
Multiple functions (resonator, electronics, packaging) are merged into a single integrated structure where the resonator is directly mounted on the circuit substrate, eliminating the need for separate ceramic packages and reducing overall device size
Solution Approach 2:
The substrate serves multiple functions: it provides mechanical support, electrical connections, and thermal management, replacing the need for separate ceramic package components
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 approach enables the construction of small, low-power, high-performance oscillators with reduced stray signals and fast warm-up times, offering improved vibration sensitivity and phase noise performance.
Implementation Method 1
a quartz resonator (20) is bonded directly to a wafer (30) with active electronics (40) to form a small, low power, and low phase noise oscillator
Implementation Method 2
quartz-base oscillators are constructed using hybrid techniques
Data Source
AI summary
An oscillator having a quartz resonator, and a base wafer containing active electronics, wherein the quartz resonator is bonded directly to the base wafer and subsequently hermetically capped.