Copper Wire Bonding for RF Power Amplifier Thermal Cycling
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Solution Overview
Problem
Power amplifier electronics components used in RF cooking ovens experience unexpected failures due to thermal stresses caused by power cycling between high and low powers, despite being robust in other applications, and initial solutions like increasing wire size only exacerbate the issue by introducing resonant frequencies.
Innovation Solution
The use of copper bonding wires with diameters between 10 microns and 100 microns, along with a learning procedure that generates power cycling between high and low powers, helps in impedance matching and reduces thermal stress, improving the reliability of power amplifier electronics in the oven environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper bonding wires with diameter between 10-100 microns are used to connect semiconductor die to output matching network, then thermal stress resistance is improved and reliability is enhanced, but manufacturing precision requirements increase due to the small wire diameter
Solution Approach 1:
The patent changes the material parameter from conventional aluminum bonding wires to copper bonding wires with specific diameter range (10-100 microns). This parameter change provides lower electrical resistance and better thermal conductivity, which reduces thermal stress during power cycling operations and enhances the reliability of power amplifier electronics in RF cooking ovens.
2Strength
If larger bonding wires are used to reduce thermal stress, then strength is improved, but resonant frequencies are introduced that worsen RF performance
Solution Approach 1:
The patent optimizes the bonding wire diameter to a specific range (10-100 microns) that balances mechanical strength for thermal stress resistance with electrical properties to avoid resonant frequencies. This parameter optimization ensures the wires are thin enough to minimize RF resonance while maintaining sufficient strength to withstand thermal cycling between high and low power states.
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 significantly enhances the durability and performance of power amplifier electronics in RF cooking ovens by reducing thermal stress and increasing the number of power cycles without failure, while maintaining efficient RF energy application.
Implementation Method 1
copper bonding wires having a diameter of between about 10 microns and about 100 microns
Implementation Method 2
reducing thermal stress on an intermittently operable chipset controlling RF application for cooking
Data Source
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AI summary
Power amplifier electronics for controlling application of radio frequency (RF) energy generated using solid state electronic components may further be configured to control application of RF energy in cycles between high and low powers. The power amplifier electronics may include a semiconductor die on which one or more RF power transistors are fabricated, an output matching network configured to provide impedance matching between the semiconductor die and external components operably coupled to an output tab, and bonding wires bonded at terminal ends thereof to operably couple the one or more RF power transistors of the semiconductor die to the output matching network. The bonding wires may be copper bonding wires having a diameter of between about 10 microns and about 100 microns.