Silicon Photonics Light Source Flip-Chip Bonding
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Solution Overview
Problem
Conventional wirebond packages for silicon photonics-based optical transceivers face impedance mismatch issues due to large inductance, degrading signal quality at higher frequencies, making them unsuitable for high-speed applications above 40 GHz.
Innovation Solution
A no-wirebond chip platform with a silicon photonics light source that includes a die with a trench region and a stopper region, where a laser diode chip is flip-bonded with the p-side facing the chip site and the n-side distal, and a conductor layer connects the gain region to anode and cathode electrodes, enabling wafer-level burn-in and testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wirebond packages are used for silicon photonics-based optical transceivers, then electrical connection between chips is achieved, but impedance mismatch occurs due to large inductance, degrading signal quality at higher frequencies
Solution Approach 1:
The patent removes the wirebond interconnect structure from the package, replacing it with a direct flip-chip bonding approach where the laser chip is bonded directly to the driver chip without intermediate wire bonds. This extraction of the problematic wirebond element eliminates the large inductance and impedance mismatch issues while maintaining electrical connection functionality
Solution Approach 2:
The patent merges the laser chip and driver chip into a single integrated package unit through flip-chip bonding, creating a unified structure where the two chips are directly coupled. This merging eliminates the need for separate wirebond interconnects and creates a more compact, lower-inductance electrical path between the chips
2Area of stationary object
If wirebond packages are used, then electrical interconnection is provided, but package footprint becomes larger, increasing device size
Solution Approach 1:
The patent transitions from a planar wirebond connection approach to a three-dimensional flip-chip bonding approach. The laser chip is inverted and bonded directly to the driver chip, utilizing the vertical dimension to create direct electrical connections. This dimensional change reduces the horizontal footprint while maintaining all necessary electrical interconnections through the vertical bonding interface
3Speed
If conventional wirebond packages are used, then chip coupling is achieved, but inductance increases, limiting high-frequency signal transmission above 40 GHz
Solution Approach 1:
The patent replaces the mechanical wirebond system with a direct semiconductor-to-semiconductor flip-chip bonding system. This substitution eliminates the mechanical wirebond structure that creates large inductance, replacing it with a direct electrical contact through solder bumps or metallization layers that provide much lower inductance and support high-frequency signals above 40 GHz
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 solution reduces package size and power consumption while maintaining high-data-rate communication capabilities, overcoming the limitations of conventional wirebond packages by eliminating impedance mismatch and supporting high-speed signal transmission.
Implementation Method 1
a laser diode chip being flipped with a p-side facing the at least one chip site in the die and a n-side being distal to the chip site. The p-side includes a gain region bonded to the trench region
Data Source
AI summary
A photonics device includes a silicon wafer including a cathode region, an anode region, a trench region formed between the cathode region and the anode region, and a linear ridge formed between the cathode region and the anode region. A laser diode chip is mounted on the silicon wafer. A conductor layer disposed between the silicon wafer and the laser diode chip includes a first section disposed between the laser diode chip and the cathode region on a first side of the trench to electrically connect the laser diode chip to a cathode electrode of the photonics device and a second section disposed between the anode region and the laser diode chip on a second side of the trench to electrically connect the laser diode chip to an anode electrode of the photonics device.