Optical Module Double Slit Metal Package Design
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Solution Overview
Problem
Conventional optical modules face challenges in reducing cost and size while maintaining high-frequency signal transmission efficiency, particularly due to the complexity and expense of multilayer ceramic feed-throughs and mismatched impedance bonding methods, which lead to signal distortion and high production costs.
Innovation Solution
The optical module design features a metal package with double slits for DC and RF FPCBs, a silicon carrier with chip-to-chip bonded AWG chip, and a lens, eliminating the need for ceramic feed-throughs and using wire bonding for RF signals, which reduces manufacturing costs and minimizes signal distortion by ensuring matched impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multilayer ceramic feed-through is used for DC and RF signal wirings, then hermetic sealing is achieved, but manufacturing cost and device complexity increase significantly
Solution Approach 1:
The patent removes the ceramic feed-through component entirely from the system. Instead of using ceramic feed-through for hermetic sealing and signal transmission, the invention uses a metal package with through-holes that are directly sealed with solder, eliminating the need for complex multilayer ceramic structures while maintaining hermeticity and electrical connectivity.
Solution Approach 2:
The patent combines the functions of hermetic sealing and electrical signal transmission into a single integrated structure. The metal package with through-holes serves both as the hermetic enclosure and as the pathway for DC and RF signals, eliminating the need for separate ceramic feed-through components that perform similar functions.
2Reliability
If multilayer ceramic feed-through is used for hermetic sealing, then sealing is achieved, but production yield decreases due to difficult brazing process
Solution Approach 1:
The patent extracts the brazing process from the manufacturing workflow by replacing ceramic feed-through with a metal package that uses soldering for sealing. Soldering is a more成熟 and higher-yield process compared to brazing ceramic to metal, thus improving production yield while maintaining hermetic sealing.
Solution Approach 2:
The patent changes the material parameter from ceramic to metal for the package structure. This material substitution enables the use of soldering instead of brazing, which has higher production yield and is more compatible with automated manufacturing processes, thereby improving productivity without compromising sealing reliability.
3Reliability
If ceramic submount with thin-film matching resistor and ground via hole is used, then high frequency signal transmission is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent removes the ceramic submount with thin-film matching resistors and ground via holes from the design. Instead, it uses a metal package with solder-based grounding and impedance control through structural design, eliminating the need for expensive thin-film fabrication processes while maintaining high-frequency signal transmission performance.
Solution Approach 2:
The patent replaces expensive ceramic submounts with thin-film technology with a more economical metal package structure. The metal package achieves the necessary electrical performance through simpler, cheaper manufacturing processes such as soldering and standard PCB techniques, reducing subsidiary material costs significantly.
4Reliability
If wire bonding and soldering are used for different parts of ceramic feed-through, then RF signal transmission is achieved, but characteristic impedance mismatch increases causing signal distortion
Solution Approach 1:
The patent merges the bonding methods by using soldering throughout the entire RF signal path instead of combining wire bonding and soldering. The metal package with through-holes allows continuous soldered connections from the FPCB through the package to the internal components, maintaining consistent characteristic impedance and eliminating impedance mismatch caused by transitioning between different bonding technologies.
Data Source
AI summary
Provided herein is an optical module including an optical bench having a first step with a first depth and a second step with a second depth that is smaller than the first depth; a silicon carrier disposed above the first step, and where at least one semiconductor chip is installed; an AWG chip (Arrayed Waveguide Grating chip) secured to the second step, extends up to the first step, and is chip-to-chip bonded with the silicon carrier above the first step; a lens disposed on an upper surface of the optical bench where the first step and the second step are not formed; and a metal package surrounding the optical bench, silicon carrier, AWG chip and lens, wherein at one side of the metal package, a double slit that includes an upper slit and a lower slit are formed, a DC FPCB (Direct Current FPCB) extends from outside towards inside the metal package through the upper slit and is secured to a support formed on an inner surface of the upper slit, and an RF FPCB (Radio Frequency FPCB) extends from outside towards inside the metal package through the lower slit and is secured to an upper portion of the silicon carrier, and the upper slit and the lower slit of the double slit being sealed by an elastic epoxy.