Flip-Chip RF Transistor Assemblies With Separate Heat Paths

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Solution Overview

Problem

Conventional RF transistor amplifier packaging methods are slow and expensive due to wirebond-based assembly, which can lead to heat management issues and reduced performance in high-power, high-frequency applications.

Innovation Solution

The use of a transistor device package with a thermally conductive support structure and modular active and passive component assemblies, where the active components are mounted on the same side as the passive components, allowing for flip-chip connections and separate heat conduction paths, reducing inductance and enabling improved thermal management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If wirebond-based assembly is used, then electrical connections can be established, but assembly speed is slow and costs are high

Engineering Contradiction:

Improveassembly speedVSAvoidassembly complexity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical wirebonding process with a flip-chip mounting process where the active component assembly is directly flipped and mounted onto the passive component assembly. This substitution eliminates the need for wire bonds and adopts a more efficient direct mounting approach, significantly improving assembly speed and reducing manufacturing complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If wirebond-based assembly is used, then electrical connections can be established, but assembly costs are high

Engineering Contradiction:

Improveassembly costVSAvoidassembly structure

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent replaces the complex wirebonding machinery and processes with a simpler flip-chip mounting system. This substitution reduces equipment costs, material costs (eliminating wire bonds), and labor costs, thereby significantly reducing overall assembly costs while simplifying the manufacturing structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Temperature

If conventional packaging methods are used, then components can be connected, but heat management is insufficient

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoidthermal performance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent merges the active component assembly (containing the transistor die) directly with the passive component assembly in a stacked configuration. This merging creates integrated thermal pathways where heat generated by the active components can be efficiently conducted through the passive components and dissipated, significantly improving heat management and thermal performance.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The passive component assembly serves as a thermal intermediary between the heat-generating active components and the external environment. This intermediary structure provides dedicated thermal pathways and heat sinking capabilities, enabling efficient heat transfer and dissipation that improves overall thermal management and device reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If wire bonds are used, then electrical connections can be made, but inductance is high and performance is reduced

Engineering Contradiction:

Improveelectrical performanceVSAvoidinductance

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the wirebond electrical connection system with a direct flip-chip mounting system. This substitution eliminates the long, inductive wire bonds and creates short, low-inductance electrical pathways through the direct contact between mounting pads on the active component assembly and corresponding pads on the passive component assembly, significantly improving electrical performance.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enhances thermal performance, reduces assembly costs, and improves the reliability and efficiency of RF transistor amplifiers by eliminating the need for bond wires and providing efficient heat dissipation in high-power, high-frequency applications.

Implementation Method 1

a thermally conductive support structure on the surface of the passive component assembly and extending along one or more sides of the transistor die

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20230420430A1Modular power transistor component assemblies with flip chip interconnections

Publication Date: 2023.12.28 MACOM TECH SOLUTIONS HLDG INC

AI summary

A transistor device package includes a transistor die comprising a gate terminal, a drain terminal, and a source terminal, and a passive component assembly including the transistor die on a surface thereof and comprising one or more passive electrical components electrically coupled to the gate terminal, the drain terminal, and/or the source terminal. A mold structure may be provided on the one or more passive electrical components. One or more conductive pads may be exposed by the mold structure. A support structure may extend along one or more sides of the transistor die on the surface of the passive component assembly. The support structure may provide a cavity that extends around the transistor die, and/or may be thermally conductive. Related devices and component assemblies are also discussed.