Organic Package Substrate Piezoelectric Temperature Sensing
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Solution Overview
Problem
Conventional temperature sensors, such as resistance temperature detectors (RTDs) and electromagnetic transduction devices, occupy large areas and require bulky components, limiting their deployment in form-factor-constrained products, and silicon-based MEMS fabrication is costly and inefficient for compact temperature sensing.
Innovation Solution
Incorporating piezoelectric temperature sensing devices into organic package substrates through in-situ fabrication, using high-volume manufacturing technology, which allows for compact, cost-effective integration without external components, and enables deposition and crystallization of piezoelectric materials at lower temperatures compatible with organic substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional resistance temperature detectors (RTDs) are used for temperature sensing, then temperature measurement function is achieved, but the sensor occupies large area (~1 mm2) which limits deployment quantity and increases form factor
Solution Approach 1:
The patent replaces conventional electrical resistance-based temperature sensing (RTDs) with a piezoelectric mechanical resonance-based sensing mechanism. The piezoelectric device uses mechanical vibration and resonance frequency shifts to detect temperature changes, eliminating the need for large-area resistive sensing elements and enabling compact integration on package substrates.
Solution Approach 2:
The patent exploits changes in the mechanical resonance frequency of the piezoelectric device as a function of temperature. By monitoring the shift in resonant frequency rather than electrical resistance, the system achieves temperature sensing with significantly reduced area footprint while maintaining measurement capability.
2Measurement precision
If electromagnetic transduction temperature sensors are used, then temperature sensing is achieved, but bulky components such as permanent magnets are required which increase device complexity and form factor
Solution Approach 1:
The patent merges the temperature sensing function with the existing piezoelectric structures already present in the package substrate. The piezoelectric devices serve dual purposes: their inherent mechanical resonance properties enable temperature sensing without requiring separate electromagnetic transduction components like permanent magnets, coils, or flux gates.
Solution Approach 2:
The piezoelectric structures within the package substrate inherently possess the mechanical resonance properties needed for temperature sensing. The system leverages the self-contained mechanical and piezoelectric characteristics of these structures rather than requiring additional external electromagnetic components, thereby reducing device complexity and eliminating the need for bulky magnets.
3Area of stationary object
If silicon-based MEMS fabrication is used for temperature sensing, then compact sensors can be produced, but manufacturing cost increases and high-volume manufacturing efficiency decreases
Solution Approach 1:
The patent integrates temperature sensing functionality into the existing organic package substrate manufacturing process. The same substrate fabrication infrastructure used for producing the package substrate is leveraged to create the piezoelectric temperature sensors, eliminating the need for separate, costly silicon-based MEMS fabrication facilities and enabling high-volume manufacturing at lower cost.
Solution Approach 2:
The patent modifies the organic package substrate material properties and structure during existing manufacturing processes to incorporate piezoelectric temperature sensing capability. By adjusting processing parameters such as depositing piezoelectric material layers and creating cavity structures within the organic substrate, the system achieves compact sensor integration without requiring a complete process technology transition to silicon-based MEMS.
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 provides thin, low-cost, and highly compact temperature sensors that can be placed in multiple substrate locations, offering spatial temperature mapping and enhancing thermal management, while eliminating the need for magnets and reducing manufacturing costs.
Implementation Method 1
A piezoelectric device may be used to sense temperature based on stress induced charge generation
Implementation Method 2
A piezoelectric device may be used to sense temperature based on stress induced charge generation, or charge induced by deformation
Data Source
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AI summary
Embodiments of the invention include a temperature sensing device that includes a base structure that is positioned in proximity to a cavity of an organic substrate, an input transducer coupled to the base structure, and an output transducer coupled to the base structure. The input transducer includes a first piezoelectric material to generate vibrations which are transmitted on the base structure in response to input signals being applied to the input transducer. The output transducer includes a second piezoelectric material to receive the vibrations and to generate output signals which are used to determine a change in ambient temperature.