Multi-Layer Antipad Structure for Millimeter-Wave Signal Isolation

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Solution Overview

Problem

In multi-layer semiconductor devices, the complex mapping of transmission lines between layers leads to unwanted interactions, which become significant as device dimensions reduce, necessitating an improved method to resolve fabrication challenges and achieve optimal operation, especially for millimeter wave frequencies used in future communication systems like 5G and beyond.

Innovation Solution

The implementation of irregular antipad structures and shapes within the layers of integrated circuits (ICs) to modify electrical current distribution, optimize equivalent capacitance, and enhance operational bandwidth, specifically through the use of flip-chip Ball Grid Array (fcBGA) technology, which introduces resonances and improves return loss in the structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If transmission lines are routed through multiple layers with complex mappings, then device functionality is achieved, but unwanted interactions between transmission lines and layers occur

Engineering Contradiction:

Improvedevice functionalityVSAvoidunwanted interactions

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces antipad structures as intermediary elements between conductive pads and surrounding ground layers. These antipads act as mediators that control electromagnetic field distribution, reducing unwanted interactions while maintaining signal transmission functionality across multiple layers.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies irregular antipad shapes with varying geometries at specific locations around conductive pads. By localizing different antipad configurations in different regions, the design optimizes electromagnetic performance locally to minimize interactions without compromising overall device functionality.

Inventive Principle:

Principle #3Local quality

2Productivity

If device dimensions are reduced to improve integration density, then manufacturing scalability is achieved, but unwanted interactions between transmission lines become more significant

Engineering Contradiction:

Improvemanufacturing scalabilityVSAvoidunwanted interactions

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the geometric parameters of antipad structures, including irregular shapes, varying sizes, and strategic positioning. By changing these parameters, the design maintains effective electromagnetic isolation even as overall device dimensions are reduced for higher integration density.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs asymmetric antipad configurations rather than uniform circular shapes. These asymmetric designs are strategically placed to counterbalance electromagnetic interactions in scaled-down devices, maintaining performance despite reduced dimensions.

Inventive Principle:

Principle #4Asymmetry

3Ease of manufacture

If conventional pad structures are used, then manufacturing simplicity is maintained, but return loss and insertion loss increase

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidreturn loss and insertion loss

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent extends the traditional two-dimensional pad design into the vertical dimension by incorporating multi-layer antipad structures. This dimensional extension allows control of electromagnetic fields in the vertical direction, reducing return loss and insertion loss while maintaining compatibility with standard manufacturing processes.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 wide band matching in frequency of interest, reducing reflection and insertion loss, thereby supporting millimeter wave operations and improving the performance of devices like Antenna in Package (AiP) based systems, enhancing manufacturing yield and operational performance.

Implementation Method 1

The implementation of irregular antipad structures and shapes within the layers of integrated circuits (ICs) to modify electrical current distribution, optimize equivalent capacitance

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

specifically through the use of flip-chip Ball Grid Array (fcBGA) technology, which introduces resonances and improves return loss in the structure

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS20230395968A1A multi-layered structure having antipad formations

Publication Date: 2023.12.07 METAWAVE CORP

AI summary

In accordance with various embodiments, a multi-layer electromagnetic device is provided. The device includes a first connectivity layer that includes a first conductive pad having a first capacitance, a feed line coupled between the first conductive pad and a transmit signal source, and a first antipad surrounding at least a portion of the first conductive pad that enables an isolation of electromagnetic signals propagating through the first conductive pad. The first antipad has a resonance that is a function of the first capacitance. The device also includes a second connectivity layer that includes a second conductive pad that enables an electrical connectivity to an external device and a plurality of layers positioned between the first connectivity layer and the second connectivity layer. The conductive pads have antipad extensions into available area of the layer as a function of a capacitance of the conductive pads.