RF Module Conductive Protrusions Heat Dissipation
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Solution Overview
Problem
Existing radio-frequency modules face challenges in achieving high power output and reducing signal transfer loss, especially at high operating frequencies, due to heat management issues and inefficient heat dissipation in semiconductor devices like HBTs, leading to thermal runaway and increased signal loss.
Innovation Solution
A radio-frequency module design that integrates a semiconductor device with both elemental and compound semiconductor elements, utilizing conductive protrusions for enhanced heat transfer and minimizing signal transfer lines by positioning the semiconductor device close to the output matching circuit, thereby improving heat dissipation and reducing signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the radio-frequency amplifier circuit is individually mounted on the module substrate, then the heat dissipation path is longer, but the module size becomes larger and signal transfer loss increases
Solution Approach 1:
The patent combines the radio-frequency amplifier circuit and band selection switch into a single semiconductor device with integrated first and second members. This merging reduces the number of separate components and mounting locations, shortening heat dissipation paths while minimizing module size. The integrated structure allows heat to be conducted more efficiently through the combined device architecture.
Solution Approach 2:
The patent transitions from a planar arrangement where components are mounted side-by-side on the substrate to a three-dimensional stacked structure with first and second members positioned at different vertical levels. This dimensional change enables shorter heat dissipation paths through vertical thermal conduction while reducing the horizontal footprint of the module.
2Speed
If the operating frequency is increased, then the radio-frequency module can handle higher frequency signals, but signal transfer loss increases
Solution Approach 1:
The patent positions the semiconductor device in close proximity to the output matching circuit and pre-arranges the conductive protrusions to establish optimal electrical connections before operation. This preliminary positioning minimizes the length of signal transfer paths, reducing signal attenuation and transfer loss at high operating frequencies.
Solution Approach 2:
The patent employs conductive protrusions with enhanced electrical conductivity specifically at critical signal transfer interfaces between the semiconductor device and output matching circuit. This localized improvement in electrical conductivity compensates for high-frequency signal losses by providing low-impedance transmission paths where they are most needed.
3Power
If the HBT operates at high power, then the output power increases, but thermal runaway occurs due to heat generation
Solution Approach 1:
The patent extracts heat from the HBT through dedicated thermal conduction paths provided by conductive protrusions that directly connect the heat-generating semiconductor elements to heat-sinking structures. This separation of thermal management function from the electrical circuit allows high power operation while maintaining thermal stability through efficient heat extraction.
Solution Approach 2:
The conductive protrusions serve as thermal intermediaries between the HBT and the module substrate or heat sink. These intermediary structures provide low-thermal-resistance pathways that facilitate efficient heat transfer from the high-power HBT, preventing thermal runaway while allowing high output power operation.
4Ease of manufacture
If wire bonding is used to electrically couple components, then the module can be assembled, but signal transfer loss increases and module size increases
Solution Approach 1:
The patent replaces the mechanical wire bonding process with direct electrical contact through conductive protrusions. This substitution eliminates the need for wire bonds while providing shorter, lower-loss electrical connections. The conductive protrusions establish direct metallurgical or mechanical contact that offers superior electrical performance compared to wire bonding.
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 design enables improved heat release characteristics and reduced signal transfer loss, allowing for higher power output and more efficient performance in radio-frequency amplifier circuits.
Implementation Method 1
Two heat transfer paths are formed; one is a heat transfer path from the semiconductor element included in the radio-frequency amplifier circuit to the first member; and the other is a heat transfer path from the semiconductor element to the module substrate via the conductive protrusion.
Data Source
AI summary
A semiconductor device including a radio-frequency amplifier circuit and a band selection switch is mounted on or in a module substrate. An output matching circuit coupled between the radio-frequency amplifier circuit and the band selection switch is on or in the module substrate. The semiconductor device includes a first member at which the band selection switch having a semiconductor element made of an elemental semiconductor is formed and a second member joined to the first member in surface contact therewith. The radio-frequency amplifier circuit including a semiconductor element made of a compound semiconductor is formed at the second member. Conductive protrusions are raised from first and second members. The semiconductor device is mounted on or in the module substrate with the conductive protrusions interposed therebetween, and in plan view, is in close proximity to the output matching circuit or overlaps a passive element constituting the output matching circuit.