PIC Coaxial Pin Bonding Without an Intermediate EIC
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Solution Overview
Problem
High-frequency electrical connections to photonic integrated circuits (PICs) face challenges with small connector pin diameters, making direct soldering impossible and requiring intermediate electronic integrated circuits (EICs) for impedance and mode matching, which increases complexity and signal loss.
Innovation Solution
A method of forming electrical connections between a PIC and a coaxial connector by dispensing solder paste or conductive adhesive onto the PIC track, aligning the connector pin with the blob, and hardening it to create a direct bond without an intermediary EIC, allowing for small diameter pin connections to narrow tracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct soldering is used to connect connector pin to PIC track, then assembly complexity is reduced, but manufacturing precision becomes impossible to achieve with small connector pin diameters
Solution Approach 1:
The patent applies preliminary action by pre-forming a solder blob on the PIC track before bringing the connector pin into position. This allows the solder to be prepared in advance at the exact location where it is needed, enabling precise alignment without requiring the connector pin to be precisely positioned during the soldering process itself. The solder blob acts as a pre-positioned bonding target that guides the connector pin placement.
Solution Approach 2:
The patent inverts the conventional soldering sequence by reversing the order of operations: instead of positioning the connector pin first and then applying solder, the method applies solder first and then positions the connector pin onto the pre-formed solder blob. This inversion allows the PIC to be moved relative to the connector to achieve alignment, rather than requiring precise positioning of the small-diameter connector pin over the track.
2Reliability
If an intermediate EIC is inserted between connector and PIC, then impedance matching is improved, but signal propagation losses increase
Solution Approach 1:
The patent extracts and removes the intermediate electronic integrated circuit (EIC) from the connection path between the coaxial connector and the PIC. By eliminating this intermediate component, the invention directly connects the connector pin to the PIC track through solder, thereby removing the additional interfaces and bonding connections that cause signal propagation losses while maintaining impedance matching through proper solder joint design.
Solution Approach 2:
The patent merges the connector pin connection directly with the PIC track by forming a solder joint between them, eliminating the separate EIC component. This direct merging reduces the number of interfaces in the signal path, minimizing signal propagation losses while maintaining electrical continuity and impedance matching through the solder joint.
3Speed
If connector pin diameter is reduced for high frequency operation, then frequency bandwidth is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-forming the solder blob on the PIC track before connector pin placement. This allows the solder to be prepared in advance with the exact amount and positioning needed, making the subsequent connection of small-diameter connector pins feasible without requiring extremely precise real-time alignment during the soldering process itself.
Solution Approach 2:
The patent uses the pre-formed solder blob as an intermediary element that facilitates the connection between the small-diameter connector pin and the PIC track. The solder blob acts as a mediator that can accommodate slight misalignments and provides a larger bonding surface area, making the manufacturing process easier despite the small connector pin dimensions required for high-frequency operation.
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 method reduces assembly complexity, lowers signal propagation losses, and simplifies impedance matching, enabling higher frequency transmissions up to 170 GHz without the need for an EIC, thus improving yield and reducing costs.
Implementation Method 1
dispensing onto an area of the track an amount of a solder paste or an electrically conductive adhesive to form a blob thereon
Implementation Method 2
heating to cause reflow of the solder blob before cooling to cause hardening
Implementation Method 3
heating to cure the electrically conductive adhesive blob before cooling to cause hardening
Data Source
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AI summary
A method of forming a direct electrical connection between a photonic integrated circuit (PIC) and a coaxial connector for a high-frequency or high-bandwidth connection of 50 GHz or more. The PIC has a planar transmission line with a track of sub-400 micrometer width. A blob of solder paste or electrically conductive adhesive is dispensed onto the track. The PIC is then moved relative to the coaxial connector to bring its connector pin into a bonding position in which an end length portion of the connector pin is in contact with the blob. The blob is then hardened while the connector pin is held in the bonding position to form a permanent electrical connection between the connector pin and the track to which it is to be connected. A high frequency electrical connection is thus made without the use of a bridging electronic integrated circuit (EIC).