Micro-Ring Resonator Strain Sensors for In-Situ PIC Monitoring
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Solution Overview
Problem
Current methods for characterizing mechanical stresses and strains in photonic integrated circuits (PICs) during assembly and packaging are limited, as they primarily provide warpage measurements and cannot offer continuous, direct strain measurements, especially in localized regions and after packaging.
Innovation Solution
The integration of a micro-ring resonator strain sensor into the design layout of PICs or other semiconductor devices allows for in-situ strain measurement, providing quantification of mechanical strain in localized regions and enabling continuous monitoring throughout the assembly and packaging processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If warpage-based laboratory techniques are used to characterize mechanical stresses and strains, then shape change measurement is provided, but continuous direct strain measurement is not available
Solution Approach 1:
The micro-ring resonator strain sensor is integrated directly into the PIC device layout, merging the sensing function with the device structure. This eliminates the need for separate testing equipment and enables continuous in-situ strain measurement throughout assembly and packaging processes.
Solution Approach 2:
The patent replaces mechanical measurement systems (shadow-moire, interferometry) with an optical sensing system based on micro-ring resonators. The optical resonance wavelength shifts in response to strain, providing direct electrical/optical readout without complex mechanical testing equipment.
2Measurement precision
If full field warpage measurement is performed, then shape change is determined, but localized strain measurement is not possible
Solution Approach 1:
Instead of measuring the entire device surface at once (full field), the patent uses multiple discrete micro-ring resonator sensors positioned at specific locations. Each sensor provides localized strain measurement, and multiple sensors can be used to reconstruct the overall strain distribution across the device.
Solution Approach 2:
The patent implements sensors with different properties at different locations to capture localized strain characteristics. Each micro-ring resonator is positioned to measure strain at its specific location, providing spatially-resolved strain data that reveals local stress concentrations and deformation patterns.
3Reliability
If PIC is packaged, then device is protected, but access for warpage measurements is lost
Solution Approach 1:
The micro-ring resonator strain sensors are integrated into the PIC device layout before packaging. This preliminary integration ensures that the sensing functionality is already in place and operational before the device is enclosed in its final package, eliminating the need for post-packaging access or disassembly for measurements.
Solution Approach 2:
The integrated sensors enable the packaged device to self-monitor its own strain conditions without requiring external testing equipment or disassembly. The sensors continuously measure strain internally within the packaged device, providing ongoing health monitoring while the package remains sealed and protected.
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 accurate strain characterization and identification of strain thresholds that may lead to device failure, thereby improving PIC device and packaging designs, reducing manufacturing costs, and enhancing yield.
Implementation Method 1
a micro-ring resonator sensor unit for measuring strain... providing quantification of mechanical strain in localized regions
Data Source
AI summary
The present disclosure is directed to testing vehicles for optical devices and other semiconductor devices that have insitu sensor units for measuring localized strains, and methods for their use. In an aspect, the optical device may include a photonic integrated circuit device having several components including a laser, an optical amplifier, a waveguides, a modulator, a demodulator, and photodetectors. In another aspect, the sensor unit may include a micro-ring resonator strain sensor, an input grating coupler and an output grating coupler that are coupled to the micro-ring resonator strain sensor, for which the input grating coupler is coupled to a light source and the output grating coupler is coupled to an optical power meter. In yet another aspect, the sensor unit may include a temperature calibration unit having a heater and a temperature diode.