Sapphire-Substrate SAW Package With Via Conduction for Heat Dissipation
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Solution Overview
Problem
The miniaturization of surface acoustic wave (SAW) devices is hindered by the need for smaller, more reliable, and cost-effective manufacturing methods, as conventional approaches struggle with size reduction, mechanical strength, and heat dissipation while maintaining electrical connectivity and avoiding material degradation.
Innovation Solution
A SAW device utilizing a sapphire substrate as a case with a lithium tantalate (LT) substrate and a via conductor through-hole for electrical connection, combined with a heat dissipation mechanism, where the sapphire substrate provides mechanical strength and reduces the device's thickness, and the via conductor facilitates efficient heat dissipation and electrical connectivity without the need for external wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional manufacturing methods are used for SAW devices, then electrical connectivity and basic functionality are maintained, but device size cannot be sufficiently reduced and manufacturing cost remains high
Solution Approach 1:
The patent merges the case structure and substrate into a single integrated sapphire substrate. The sapphire substrate serves dual functions as both the mechanical case housing and the acoustic wave substrate, eliminating the need for separate case and substrate components. This integration reduces device size while simplifying manufacturing processes.
Solution Approach 2:
The sapphire substrate performs multiple functions simultaneously: it serves as the case housing, the acoustic wave substrate, the heat dissipation path, and the mechanical support structure. This multi-functionality reduces the number of components needed and enables further miniaturization without compromising manufacturing ease.
2Volume of moving object
If device size is reduced, then miniaturization is achieved, but heat dissipation becomes insufficient and reliability decreases
Solution Approach 1:
The sapphire substrate inherently provides heat dissipation functionality through its high thermal conductivity. The substrate serves itself by conducting heat away from the active regions without requiring additional heat sink components. This self-service heat dissipation mechanism maintains reliability in the miniaturized device structure.
Solution Approach 2:
The patent employs asymmetric thickness design where the sapphire substrate has different thicknesses in different regions. The region under the heating element has greater thickness to provide enhanced heat dissipation capacity, while other regions are thinner to reduce overall device size. This asymmetric design optimizes heat dissipation where needed while maintaining miniaturization.
3Reliability
If external wiring is used for electrical connection, then connectivity is established, but device complexity and size increase
Solution Approach 1:
The patent extracts the wiring function from external connections and integrates it directly into the sapphire substrate through embedded conductors. The conductors are formed within the substrate itself, eliminating the need for external wiring harnesses or connection elements. This reduces device complexity and size while maintaining reliable electrical connectivity.
Solution Approach 2:
The conductors are nested within the sapphire substrate structure. The electrical connection elements are embedded inside the substrate material, creating a nested configuration where the wiring is contained within the case-substrate integration. This nested design reduces external complexity while maintaining internal connectivity.
4Reliability
If multiple separate components are used, then functionality is comprehensive, but manufacturing effort and cost increase
Solution Approach 1:
The patent combines multiple functional components into a single sapphire substrate integration. The case, substrate, heat dissipation path, and mechanical support are merged into one monolithic structure. This reduction in component count directly decreases manufacturing effort and assembly steps while maintaining all necessary device functionalities.
Solution Approach 2:
The sapphire substrate is designed to perform multiple functions simultaneously: structural housing, acoustic wave propagation, heat dissipation, and mechanical support. This multi-functionality eliminates the need for separate dedicated components for each function, thereby reducing manufacturing complexity and cost while preserving comprehensive device functionality.
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 SAW device achieves a compact, reliable, and cost-effective design with enhanced mechanical strength, efficient heat dissipation, and simplified manufacturing, while maintaining high electrical connectivity and reducing the risk of material degradation.
Implementation Method 1
a via conductor formed in a through-hole which continuously penetrates through the sapphire substrate and the LT substrate
Implementation Method 2
a lithium tantalate (LT; LiTaO3) substrate including a SAW element
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3(a)~3(e)
AI summary
A SAW device includes a SAW element, a conductor connected to the SAW element, an LT substrate including the SAW element, and a case for housing the LT substrate including the SAW element. The case includes a cover part, a lateral part, and a bottom part. The bottom part is including a sapphire substrate, the LT substrate is positioned on a first surface of the sapphire substrate, the first surface serving as an inner surface of the case, and a second surface opposite to the first surface serves as an outer surface of the case. The conductor includes a via conductor provided in a through-hole continuously penetrating through the sapphire substrate and the LT substrate.