GaN Flip-Chip Optocoupler Packaging for Compact High-Bandwidth Isolation
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Solution Overview
Problem
Existing optocouplers are too large for use in micro circuit technologies like HDI PCBs and have limited bandwidth, operating frequency, and temperature range, making them unsuitable for modern applications.
Innovation Solution
Employing GaN-based LEDs and photo-detectors that operate in the violet to blue light spectrum, utilizing flip-chip technology and Chip Scale Packaging (CSP) arrangements to create a smaller, more efficient optocoupler with increased bandwidth and temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional LED-Photodiode optocouplers are used, then voltage isolation and basic signal transfer are achieved, but the physical size is too large for micro circuit technologies
Solution Approach 1:
The patent implements Chip Scale Packaging (CSP) where the photodetector chip is mounted directly on the LED chip substrate, creating a nested compact structure. This nesting approach reduces the overall footprint from traditional DIP package sizes to chip-scale dimensions, enabling integration into HDI PCBs and other micro circuit technologies while maintaining all necessary functional components.
Solution Approach 2:
The patent combines the LED and photodetector into a single integrated optocoupler package with unified substrate and shared bonding structure. By merging previously separate components into one compact unit, the footprint is dramatically reduced while maintaining electrical isolation and optical coupling functions, making it suitable for modern micro circuit applications.
2Speed
If traditional optocoupler packaging is used, then basic isolation function is provided, but the bandwidth and operating frequency are limited
Solution Approach 1:
The patent extracts and eliminates unnecessary intermediate packaging layers and complex isolation structures from traditional optocoupler designs. By directly mounting the photodetector on the LED substrate and using simplified bonding wire configurations, the packaging complexity is reduced while bandwidth is enhanced through improved optical coupling efficiency and reduced parasitic capacitance.
Solution Approach 2:
The patent optimizes the packaging structure to be more dynamic and adaptable, allowing for better heat dissipation and electrical performance. The CSP design enables improved signal transmission paths and reduced parasitic effects, thereby increasing operating frequency and bandwidth while maintaining functional isolation.
3Temperature
If traditional optocouplers are used, then standard isolation performance is achieved, but the operating temperature range is limited
Solution Approach 1:
The patent employs composite material structures in the packaging, including specialized substrates, bonding materials, and encapsulants that maintain their electrical and mechanical properties across a wide temperature range. These composite materials provide thermal stability and preserve isolation performance from -55°C to +125°C, extending the operating temperature range while maintaining reliability.
Solution Approach 2:
The patent modifies key packaging parameters such as material selection, bonding techniques, and structural dimensions to optimize thermal performance. By changing these parameters, the optocoupler achieves stable isolation characteristics across extended temperature ranges, improving reliability in harsh environmental conditions.
4Speed
If GaN-based LEDs and photo-detectors are used with flip-chip technology, then bandwidth and temperature range are increased, but manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary preparation of the LED and photodetector chips before final assembly, including pre-mounted configurations and pre-established bonding patterns. This preliminary action simplifies the final assembly process despite using advanced GaN-based materials and flip-chip technology, as critical steps are completed during chip fabrication rather than during optocoupler assembly.
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 GaN-based optocouplers achieve a higher operating lifespan, frequency, and temperature range, with a reduced footprint, enabling their use in micro circuit technologies and applications such as LED lighting.
Implementation Method 1
a GaN-based Light Emitting Diode (LED); and a GaN-based photo-detector, wherein the LED generates violet to blue light
Implementation Method 2
a GaN-based photo-detector configured to receive violet to blue light from the GaN-based LED and generate an electrical signal
Data Source
AI summary
An optocoupler includes a GaN-based Light Emitting Diode (LED) and a GaN-based photo-detector, where at least one of the LED and photo-detector is a flip chip. In some embodiments, the photo-detector comprises a GaN-based LED configured to operate as a photo-detector.