Thermally Conductive Dielectric Layer for RF Heat Dissipation
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Solution Overview
Problem
Conventional monolithic RF circuits face performance degradation due to heat generated by semiconductor devices, which limits cell density and RF linearity, as conventional thermal conductors used for heat dissipation are also electrical conductors, interfering with RF signals.
Innovation Solution
Integration of a thermally conductive but electrically isolating layer with semiconductor wafers, utilizing materials like aluminum nitride or beryllium oxide with high thermal conductivity and high resistivity, to dissipate heat without interfering with electrical signals, allowing for increased cell density and improved RF linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional thermal conductors (e.g., metals) are used to dissipate heat from semiconductor devices, then heat dissipation is improved, but RF linearity deteriorates due to electrical conduction interfering with RF signals
Solution Approach 1:
The patent introduces an intermediate layer (thermally conductive dielectric layer) between the semiconductor device and the conductive substrate. This intermediate layer acts as a mediator that transfers heat from the device to the substrate while blocking electrical conduction paths that would interfere with RF signals, thus resolving the contradiction between heat dissipation and RF linearity
Solution Approach 2:
The patent employs composite material structures combining thermally conductive dielectric materials with conductive substrates. These composite materials provide both thermal conduction pathways for heat dissipation and electrical isolation to maintain RF signal integrity, simultaneously achieving improved heat dissipation and preserved RF linearity
2Reliability
If spacing between neighboring semiconductor devices is increased to prevent overheating, then device performance is improved, but cell density deteriorates
Solution Approach 1:
The thermally conductive dielectric layer acts as an efficient heat transfer intermediary that conducts heat away from device regions more effectively. This allows devices to be placed closer together (increased cell density) while still maintaining adequate heat dissipation and preventing overheating, thus resolving the contradiction between device performance and cell density
3Temperature
If conventional thermal conductors are used for heat dissipation, then heat removal is improved, but electrical isolation deteriorates due to interference with RF signals
Solution Approach 1:
The thermally conductive dielectric layer serves as an intermediary that enables heat removal from semiconductor devices to the substrate while providing electrical isolation. This intermediate layer blocks harmful electrical conduction paths that would otherwise interfere with RF signals, simultaneously achieving effective heat removal and electrical isolation
Solution Approach 2:
The patent changes the material parameters of the intermediate layer to achieve both high thermal conductivity and high electrical resistivity. By selecting dielectric materials with appropriate thermal and electrical properties, the system achieves effective heat removal while maintaining electrical isolation to prevent RF signal interference
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 dissipates heat from semiconductor devices, enabling closer device placement and increased cell density, leading to better performance characteristics such as higher current carrying capability and reduced power loss, while maintaining RF signal integrity by eliminating parasitic effects.
Implementation Method 1
integration of a thermally conductive but electrically isolating layer with semiconductor wafers, utilizing materials like aluminum nitride or beryllium oxide with high thermal conductivity and high resistivity, to dissipate heat
Data Source
AI summary
A semiconductor structure includes a semiconductor wafer having at least one semiconductor device integrated in a first device layer, a thermally conductive but electrically isolating layer on a back side of the semiconductor wafer, a front side glass on a front side of the semiconductor wafer, where the thermally conductive but electrically isolating layer is configured to dissipate heat from the at least one semiconductor device integrated in the semiconductor wafer. The thermally conductive but electrically isolating layer is selected from the group consisting of aluminum nitride, beryllium oxide, and aluminum oxide. The at least one semiconductor device is selected from the group consisting of a complementary-metal-oxide-semiconductor (CMOS) switch and a bipolar complementary-metal-oxide-semiconductor (BiCMOS) switch. The semiconductor structure also includes at least one pad opening extending from the back side of the semiconductor wafer to a contact pad.