AiP Substrate Stack Ceramic Organic Antenna Design

Solution Overview

Problem

Existing antenna-in-package (AiP) devices face challenges in achieving good device performance and cost efficiency, particularly at high frequency communication applications like 60 GHz to 80 GHz, where organic substrates with lower dielectric constants result in larger antenna dimensions and thicker metallic reflectors that are impractical for most applications.

Innovation Solution

A substrate stack comprising a ceramic substrate with a higher dielectric constant attached to an organic substrate, where the antenna is on the top side of the ceramic substrate, and an IC die is positioned between the two substrates, filled with a mold compound, enabling efficient coupling and miniaturization without degrading performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ceramic substrate with high dielectric constant is used, then antenna gain and bandwidth are improved, but manufacturing cost increases

Engineering Contradiction:

Improveantenna performanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The substrate is divided into two segments: a ceramic substrate layer for high-frequency antenna operation and an organic substrate layer for cost-effective packaging and interconnection. This segmentation allows each layer to fulfill its specific function optimally while reducing overall manufacturing cost.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite substrate structure combining ceramic and organic materials. The ceramic layer provides high dielectric constant for antenna performance, while the organic layer provides cost benefits and mechanical support, creating a composite material solution that balances performance and cost.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If an organic substrate with low dielectric constant is used, then manufacturing cost is reduced, but antenna dimensions and metallic reflector thickness increase

Engineering Contradiction:

Improvemanufacturing costVSAvoidantenna dimensions

Core Design Contradiction:

Ease of manufactureVSLength of moving object

Solution Approach 1:

The substrate is divided into two segments: a ceramic substrate layer for high-frequency antenna operation and an organic substrate layer for cost-effective packaging and interconnection. This segmentation allows each layer to fulfill its specific function optimally while reducing overall manufacturing cost.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the substrate structure have different material properties optimized for their specific functions. The ceramic layer near the antenna provides high dielectric constant for compact dimensions, while the organic layer in the packaging region provides cost benefits without affecting antenna performance.

Inventive Principle:

Principle #3Local quality

3Reliability

If a thick metallic reflector is used with organic substrate, then antenna performance is maintained, but device form factor becomes impractical

Engineering Contradiction:

Improveantenna performanceVSAvoiddevice form factor

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

Different regions of the substrate structure have different material properties optimized for their specific functions. The ceramic layer near the antenna provides high dielectric constant for compact dimensions, while the organic layer in the packaging region provides cost benefits without affecting antenna performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The dielectric constant parameter is changed by using ceramic material with higher εr value in the substrate stack, which directly reduces the required thickness of the metallic reflector and overall antenna dimensions while maintaining the same antenna performance characteristics.

Inventive Principle:

Principle #35Parameter changes

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 configuration provides high-performance antennas with increased bandwidth and gain while reducing costs by using a lower-cost organic substrate, allowing for smaller form factors and practical implementation of metallic reflectors, thus achieving cost-competitive, high-performance AiP devices.

Implementation Method 1

a high dielectric constant substrate such as a ceramic substrate typically being aluminum oxide (Al2O3) that has a relative dielectric constant (εr) of about 9.8, is helpful for enhancing antenna performance

Methodology Applied

Scientific EffectDielectric constant: Dielectric Permittivity

Implementation Method 2

efficient integrated antennas operating at mm-wave frequencies generally need a metallic reflector positioned away from the antenna at a distance λ/4

Methodology Applied

Scientific EffectElectromagnetic reflection: Reflection

Implementation Method 3

A mold compound fills the gap between the ceramic substrate and the organic substrate

Methodology Applied

Scientific EffectDielectric insulation: Dielectric Permittivity

Data Source

PatentUS10910705B2Antenna in package device having substrate stack

Publication Date: 2021.02.02 TEXAS INSTRUMENTS INC

AI summary

An antenna-in-package (AiP) device includes a substrate stack having a ceramic substrate attached to an organic substrate, where a dielectric constant of the ceramic substrate is higher than a dielectric constant of the organic substrate. An antenna is on a top side of the ceramic substrate. An integrated circuit (IC) die is flip chip attached to a bottom side of the ceramic substrate or to a top surface of the organic substrate. The IC die includes a radio circuit including at least a transmitter, and there is at least one interconnect for coupling the radio circuit to the antenna.