Wafer-Level Optical Subassembly Hermetic Sealing

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Solution Overview

Problem

Conventional packaging methods for optoelectronic components in optical transceiver modules are costly, labor-intensive, and inefficient, with slow hermetic sealing and manual alignment processes, and lack hermetic sealing and high-throughput capabilities.

Innovation Solution

A wafer-level packaged optical subassembly is developed, featuring a substrate with bonded top and base layers, hermetic wafer bonding, and precision-aligned cavities for active optoelectronic elements, along with a glass top window cover for optical signal coupling, enabling efficient and cost-effective manufacturing and integration with standard SMT processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional metal-can packaging is used for hermetic sealing, then sealing reliability is improved, but production cost increases and production speed decreases

Engineering Contradiction:

Improvehermetic sealing reliabilityVSAvoidproduction speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The packaging structure is divided into a substrate element with integrated cavities and a separate window cover, allowing parallel processing of multiple units on wafers before final assembly, thereby increasing production speed while maintaining hermetic sealing through precise cavity integration

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Cavities for accommodating optoelectronic elements are pre-formed in the substrate element during wafer fabrication using photolithography and etching, enabling batch processing of multiple units simultaneously and eliminating time-consuming post-assembly sealing operations

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If manual active alignment process is used for lens cap fixation, then coupling precision is improved, but production time increases

Engineering Contradiction:

Improvecoupling precisionVSAvoidproduction time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The substrate element integrates alignment features including peripheral cavities and protrusions that automatically align with corresponding features on the window cover and external components, enabling self-alignment during assembly without manual intervention while maintaining precise optical coupling

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Alignment functions are merged into the substrate element structure itself through integrated alignment features, combining mechanical support, optical alignment, and component positioning into a single element that guides precise assembly without separate alignment operations

Inventive Principle:

Principle #5Merging (Combining)

3Manufacturing precision

If specialty high-precision lens bonding equipment is used for polymer lens bonding, then bonding precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvelens bonding precisionVSAvoidequipment complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention replaces expensive specialty lens bonding equipment with standard photolithography and etching tools already present in semiconductor fabrication facilities, using the substrate element's pre-formed cavities and alignment features to achieve precise lens positioning through conventional, widely-available manufacturing equipment

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Device complexity

If conventional packaging processes are used that handle one module at a time, then process control is simplified, but productivity decreases

Engineering Contradiction:

Improveprocess control complexityVSAvoidproduction throughput

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The substrate element is designed as an array of identical, independently-defined units with standardized cavities and alignment features, allowing parallel fabrication of multiple optical subassemblies on a single wafer while maintaining uniform process parameters across all units through automated batch processing

Inventive Principle:

Principle #1Segmentation

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 simplifies packaging, reduces costs, and enables high-throughput production with precise alignment and hermetic sealing, improving module production yield and compatibility with standard surface mount technology.

Implementation Method 1

a substrate element, the substrate element including a top layer and a base layer being bonded with the top layer

Methodology Applied

Scientific EffectWafer bonding: Welding

Data Source

PatentUS9679784B2Wafer-level packaged optical subassembly and transceiver module having same

Publication Date: 2017.06.13 WELLS FARGO BANK NA

AI summary

A wafer-level packaged optical subassembly includes: a substrate element, the substrate element including a top layer and a base layer being bonded with the top layer; a top window cover being bonded with the top layer of the substrate element; and a plurality of active optoelectronic elements disposed within the substrate element. At least one primary cavity is defined in the substrate element by the top layer and the base layer, and configured for accommodating the active optoelectronic elements. A plurality of peripheral cavities are defined around the at least one primary cavity as alignment features for external opto-mechanical parts.