Lateral GaN Packaging with Insulating Adhesive

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Solution Overview

Problem

Conventional packaging formats for lateral GaN power devices, such as GaN/Si, face limitations due to vertical leakage current and incompatibility with JEDEC standard frames, especially under high voltage conditions, as they are designed for vertical devices with electrodes on opposite sides and current flow perpendicular to the device plane.

Innovation Solution

A packaging method for lateral semiconductor power devices that uses a back-plate with an electrically insulating and thermally conducting adhesive to reduce vertical leakage current, where the back-plate is either entirely metal or includes a metal portion with an insulating and conducting material, allowing electrodes to be wire-bonded to metal leads and preventing vertical current flow, thus enabling the use of standard JEDEC frames.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional packaging formats designed for vertical devices are used for lateral GaN power devices, then device packaging can be achieved, but vertical leakage current occurs at high voltage

Engineering Contradiction:

Improvebreakdown voltageVSAvoidvertical leakage current

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

An electrically insulating and thermally conducting adhesive is introduced as an intermediary material between the lateral GaN power device and the metal back-plate. This adhesive layer prevents vertical leakage current while maintaining thermal dissipation, effectively blocking the harmful electrical path without compromising heat management.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The packaging structure employs a composite approach by combining metal back-plate with electrically insulating and thermally conducting adhesive materials. This composite construction allows simultaneous achievement of electrical isolation (to prevent leakage) and thermal conduction (for heat dissipation), resolving the contradiction between electrical and thermal requirements.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If conventional packaging formats for vertical devices are used, then packaging structure can be established, but compatibility with lateral device electrode arrangement is lost

Engineering Contradiction:

Improvecompatibility with lateral deviceVSAvoidpackaging structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of attempting to adapt vertical device packaging to lateral devices, the invention inverts the approach by designing a packaging structure specifically optimized for lateral devices. The back-plate configuration and electrode connections are arranged to match the lateral electrode topology, making the packaging inherently compatible with lateral GaN power devices while simplifying the overall structure.

Inventive Principle:

Principle #13The other way round (Inversion)

3Temperature

If metal back-plate is used for electrical connection, then thermal conduction is achieved, but electrical insulation is lost

Engineering Contradiction:

Improvethermal conductionVSAvoidvertical leakage current

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The electrically insulating and thermally conducting adhesive serves as a mediator between the metal back-plate and the lateral GaN device. It allows thermal energy to pass through while blocking electrical current, effectively decoupling the thermal and electrical functions in the packaging structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The packaging structure exhibits local quality differentiation where different regions perform different functions: the metal back-plate provides thermal conduction and mechanical support, while the electrically insulating adhesive layer provides electrical isolation. This spatial differentiation of material properties allows simultaneous achievement of thermal conduction and electrical insulation.

Inventive Principle:

Principle #3Local quality

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 effectively reduces or eliminates substrate vertical leakage current, enhances breakdown voltage, and allows for the use of standard packaging formats, making it suitable for high-power lateral devices while maintaining compatibility with conventional circuit designs.

Implementation Method 1

an electrically insulating and thermally conducting adhesive disposed between the lower surface of the lateral semiconductor power device chip and the back-plate

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

an electrically insulating and thermally conducting adhesive disposed between the lower surface of the lateral semiconductor power device chip and the back-plate

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentUS11107755B2Packaging for lateral high voltage GaN power devices

Publication Date: 2021.08.31 GANPOWER INT INC

AI summary

Packaging methods and structures for lateral high voltage gallium nitride (GaN) devices achieve electrical isolation while also maintaining thermal dissipation. The electrical isolation reduces or eliminates vertical leakage current, improving high voltage performance. The packages may use or be compatible standards such as JEDEC, which reduces packaging cost and facilitates implementation of the packaged devices in conventional circuit design approaches.