Photonic Assembly Low-Temperature Solder for Pre-Integration Testing
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Solution Overview
Problem
The reflow temperature of solder connections in photonic devices is often higher than the cure temperature of the adhesive, making it difficult to test electrical and optical connections before attaching the photonic die to the substrate, leading to increased production costs and lower yields due to scrapping of entire devices if issues are detected after assembly.
Innovation Solution
Using solder connections with a reflow temperature less than the cure temperature of the adhesive allows for pre-assembly testing of optical and electrical connections between optical devices and photonic dies, ensuring proper alignment and reducing damage during the reflow process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional solder connections with high reflow temperature are used, then strong electrical connections are achieved, but the adhesive cures improperly and alignment is compromised
Solution Approach 1:
The patent changes the temperature parameter of the solder reflow process by using low-temperature solder (melting point 100-150°C) instead of traditional high-temperature solder. This parameter change allows the solder reflow to occur at temperatures that do not exceed the adhesive cure temperature, thereby preventing adhesive degradation while maintaining strong solder connections and preserving optical alignment precision.
2Productivity
If photonic die is attached to substrate before optical device attachment, then assembly efficiency is improved, but testing capability is lost
Solution Approach 1:
The patent enables preliminary testing of electrical and optical connections after optical device attachment to photonic die, but before attaching the photonic die to the substrate. The low-temperature solder reflow process is designed to occur after this intermediate testing stage, allowing faults to be detected and corrected in the photonic assembly before final integration, thereby maintaining both productivity and testing capability.
3Reliability
If high temperature reflow is used for solder connections, then reliable electrical connections are formed, but adhesive damage occurs
Solution Approach 1:
The patent changes the temperature parameter of the soldering process by selecting low-temperature solder materials with melting points between 100-150°C. This parameter change ensures that the solder reflow temperature remains below the adhesive cure temperature, preventing adhesive softening or degradation while still forming reliable electrical connections through proper solder reflow.
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 the identification and discard of faulty photonic assemblies before substrate attachment, increasing production yield and reducing costs by allowing for testing before integration, while maintaining the integrity of the adhesive and preventing misalignment.
Implementation Method 1
The photonic assembly is attached to the substrate by reflowing one or more solder connections formed between the photonic assembly and the substrate
Implementation Method 2
The optical device is attached to the photonic die with an adhesive to form an optical connection between the optical assembly and the photonic die
Data Source
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AI summary
Photonic devices include a photonic assembly and a substrate coupled to the photonic assembly. The photonic assembly includes a photonic die and an optical device coupled to the photonic die with an adhesive to form an optical connection between the optical device and the photonic die. The photonic assembly is coupled to the photonic assembly by reflowing a plurality of solder connections at temperature that is less than a cure temperature of the adhesive.