Hybrid Surface Mountable Packages for High-Speed Interconnects

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Solution Overview

Problem

Current surface mountable packages with grid array technology are limited by bandwidth, making it difficult to achieve very-high-speed interconnects for microwave integrated circuits (MICs) above 25 Gbps, especially when multiple co-packaged MIC chips are required, due to unfavorable RF/microwave performance and cavity resonances with spurious modes.

Innovation Solution

The development of hybrid surface mountable packages that include multiple co-packaged MICs connected via very-high-speed interconnects using strong coupling co-planar waveguide (CPWG) transmission lines and wall feed thrus, which minimize spurious modes and cavity resonances by confining electromagnetic radiation and optimizing ground via placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If grid array technology is used for surface mountable packages, then the packages can be manufactured with existing technology, but the bandwidth is limited and cannot achieve very-high-speed interconnects above 25 Gbps

Engineering Contradiction:

Improvedata transfer speedVSAvoidRF/microwave performance

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The package is divided into multiple sealed cavities, each housing MIC chips and their associated interconnect structures. This segmentation isolates RF signals within individual cavities, preventing interference and maintaining signal integrity at very high speeds above 25 Gbps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Strong coupling co-planar waveguide (CPWG) transmission lines are introduced as intermediary structures to connect MIC chips within sealed cavities. These CPWG transmission lines provide controlled impedance and minimize signal loss, enabling reliable very-high-speed interconnects where traditional grid array technologies fail.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple MIC chips are co-packaged to integrate multiple functions, then device functionality is improved, but cavity resonances and spurious modes occur causing unfavorable RF/microwave performance

Engineering Contradiction:

Improvedevice functionalityVSAvoidcavity resonances and spurious modes

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The harmful cavity resonances and spurious modes are extracted or eliminated by introducing ground vias that extend through the housing walls. These ground vias act as artificial magnetic conductors that suppress resonant modes and spurious signals, allowing multiple MIC chips to co-package without RF interference.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Ground vias are strategically placed at specific locations around the sealed cavities and along the housing walls. This localized placement creates regions of enhanced electromagnetic shielding and controlled impedance, suppressing cavities resonances and spurious modes only where they occur without affecting overall package performance.

Inventive Principle:

Principle #3Local quality

3Reliability

If strong coupling CPWG transmission lines and wall feed thrus are used to minimize spurious modes, then RF/microwave performance is improved, but the device complexity increases

Engineering Contradiction:

ImproveRF/microwave performanceVSAvoidinterconnect structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The ground vias are merged with the housing structure itself, extending through the housing walls to provide both mechanical support and electromagnetic shielding functions. This integration reduces the need for separate shielding structures and simplifies manufacturing despite the advanced RF performance requirements.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The wall feed thrus serve multiple functions: they provide RF signal transmission between MIC chips, act as ground references for the CPWG transmission lines, and serve as shielding structures to suppress external interference. This multi-functionality reduces the overall component count and simplifies the interconnect structure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

These packages enable favorable RF/microwave performance and eliminate spurious modes, allowing data transfer rates up to 40 Gbps or higher with reduced radiation and resonance issues, effectively addressing the limitations of existing technologies.

Implementation Method 1

very-high-speed interconnects using strong coupling co-planar waveguide (CPWG) transmission lines and wall feed thrus, which minimize spurious modes and cavity resonances by confining electromagnetic radiation

Methodology Applied

Scientific EffectElectromagnetic radiation confinement: Waveguide

Implementation Method 2

very-high-speed interconnects using strong coupling co-planar waveguide (CPWG) transmission lines and wall feed thrus

Methodology Applied

Scientific EffectElectromagnetic signal transmission: Waveguide

Data Source

PatentUS7898370B2Hybrid surface mountable packages for very high speed integrated circuits

Publication Date: 2011.03.01 II VI DELAWARE INC

AI summary

In one example, a hybrid surface mountable package includes a housing at least partially defining a sealed cavity, two microwave integrated circuits (MIC) chips positioned inside the sealed cavity, and a very-high-speed interconnect connecting the two MIC chips to each other. The very-high-speed interconnect includes strong coupling co-planar waveguide (CPWG) transmission lines.