Embedded GaN HEMT Packaging with Dielectric Transition Temperature
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Solution Overview
Problem
Existing packaging solutions for high voltage and high temperature GaN power semiconductor devices, such as GaN HEMTs, face reliability issues due to degradation under high electric fields and elevated temperatures, with conventional dielectric epoxy materials failing to maintain reliable operation.
Innovation Solution
A dielectric polymer composition with specific conduction transition temperature (Tc), first (low temperature) activation energy (EaLow), and second (high temperature) activation energy (EaHigh) values is used to ensure conductivity remains below a reliability threshold, even at high operating voltages and temperatures, and a test methodology is developed to characterize and select suitable dielectric materials for embedded packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dielectric epoxy materials are used for packaging, then manufacturing is easier and cost is lower, but reliability deteriorates under high electric fields and elevated temperatures
Solution Approach 1:
The patent applies parameter changes by carefully selecting and optimizing the dielectric material's conduction transition temperature (Tc) and activation energy values (EaLow and EaHigh) to ensure conductivity remains below reliability thresholds under high voltage and temperature conditions. This involves changing the physical and chemical parameters of the dielectric material to achieve the desired performance characteristics.
Solution Approach 2:
The patent employs composite materials by using a dielectric polymer composition with specific conduction characteristics that combines multiple material properties to achieve both reliability under high stress conditions and manufacturability. The composite nature of the dielectric material allows it to maintain low conductivity across a wide temperature range while remaining processable.
2Productivity
If smaller geometries are used for dense packaging, then productivity increases, but reliability deteriorates due to higher electric fields
Solution Approach 1:
The patent resolves this contradiction by changing the dielectric material parameters, specifically selecting materials with appropriate conduction transition temperatures and activation energies that maintain low conductivity even in the high electric field environments created by smaller, denser package geometries. This allows compact packaging without sacrificing reliability.
3Productivity
If higher operating temperatures are targeted, then productivity increases through faster switching, but reliability deteriorates due to material degradation
Solution Approach 1:
The patent addresses this contradiction by selecting dielectric materials with conduction transition temperatures and activation energy characteristics that maintain stable, low conductivity at elevated operating temperatures. This enables the device to operate at higher temperatures for improved productivity while the specialized dielectric material prevents degradation and maintains reliability.
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
The solution effectively extends the reliable operation of GaN HEMTs and other power semiconductor devices by maintaining conductivity below specified thresholds, enhancing reliability and performance at higher temperatures and voltages, and supporting smaller geometries for more dense packaging.
Implementation Method 1
the dielectric body comprises a dielectric polymer composition that provides a conductivity less than a reliability threshold value of conduction for the rated operating voltage and temperature
Implementation Method 2
the dielectric body comprises a dielectric polymer composition that provides a conductivity less than a reliability threshold value of conduction
Data Source
AI summary
Embedded packaging for high voltage, high temperature operation of power semiconductor devices is disclosed, wherein a semiconductor die is embedded in a dielectric body comprising a dielectric polymer composition characterized by a conductivity transition temperature Tc, a first activation energy EaLow for conduction in a temperature range below Tc, and a second activation energy EaHigh for conduction in a temperature range above Tc. A test methodology is disclosed for selecting a dielectric epoxy composition having values of Tc, EaLow, and EaHigh that provide a conduction value below a required reliability threshold, e.g. ≤5×10−13 S/cm, for a specified operating voltage and temperature. For example, the power semiconductor device comprises a GaN HEMT rated for operation at ≥100V wherein the package body is formed from a laminated dielectric epoxy composition for operation at >150 C, wherein Tc is ≥75 C, EaLow is ≤0.2 eV and EaHigh is ≤1 eV, for improved reliability for high voltage, high temperature operation.