Porous Substrate Micro Heater for Thermal Insulation
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Solution Overview
Problem
Conventional micro sensors face challenges in achieving efficient heat insulation and reducing power consumption, leading to heat loss and electrode damage, particularly when using porous layers and liquid photoresist in the manufacturing process.
Innovation Solution
A micro sensor design featuring a substrate with vertically extending pores, a heater electrode formed on the surface from which the aluminum material and barrier layer are removed, and a protective layer to prevent oxidation, along with air gaps surrounding the heater wiring line for enhanced heat insulation and reduced thermal capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a silicon substrate with large heat conductivity is used to reduce heat loss, then heat insulation is improved, but the sensor size cannot be reduced further due to the large substrate area required
Solution Approach 1:
The patent uses a porous substrate (such as porous anodic aluminum oxide) instead of a solid silicon substrate. The porous structure provides thermal insulation by trapping air pockets within the pores, while maintaining a compact form factor. This resolves the contradiction by achieving heat loss reduction through material structure rather than substrate size.
2Loss of energy
If a suspended structure is formed by bulk macro-machining to reduce heat transfer loss, then heat insulation is improved, but the manufacturing process becomes incompatible with standard CMOS semiconductor processes
Solution Approach 1:
The patent employs a porous substrate that can be fabricated using anodization processes compatible with standard CMOS semiconductor manufacturing. The porous structure is formed through electrochemical anodization of aluminum or aluminum alloys, which can be integrated into existing semiconductor fabrication lines, thereby maintaining manufacturing compatibility while achieving heat insulation.
Solution Approach 2:
The patent changes the physical and chemical parameters of the substrate by using porous materials with controlled pore sizes, distributions, and depths. These parameter changes enable thermal insulation performance while maintaining compatibility with standard manufacturing processes through established anodization techniques.
3Manufacturing precision
If liquid photoresist is used to form electrode patterns, then pattern resolution is improved, but the photoresist flows into pores and patterns cannot be smoothly formed
Solution Approach 1:
The patent uses a porous substrate surface that, when properly treated or coated with appropriate barrier layers, prevents liquid photoresist from penetrating into the pores. This allows high-resolution electrode patterns to be formed smoothly without photoresist loss, resolving the contradiction between pattern resolution and formation smoothness.
Solution Approach 2:
The patent introduces an intermediary layer (such as a barrier layer or adhesion layer) between the porous substrate and the liquid photoresist. This intermediary prevents the photoresist from flowing into the pores while maintaining good adhesion and pattern fidelity, thereby enabling smooth pattern formation with high resolution.
4Loss of energy
If the sensor structure is separated from the substrate to form a suspended structure, then heat insulation is improved, but mechanical durability is reduced
Solution Approach 1:
The patent uses a porous substrate that provides thermal insulation while maintaining mechanical strength through its unique structure. The porous material's interconnected network and cell wall structure provide both thermal resistance and mechanical support, eliminating the need for a fully suspended structure and thereby maintaining mechanical durability.
Solution Approach 2:
The patent employs composite material structures combining porous substrates with additional support layers or reinforcement structures. This composite approach provides both the thermal insulation benefits of the porous structure and the mechanical durability of the reinforcing elements, resolving the contradiction between heat insulation and mechanical strength.
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 design improves heat insulation, reduces power consumption, maintains mechanical durability, and prevents electrode damage, enabling the micro sensor to achieve high temperatures efficiently while being suitable for small devices like mobile devices.
Implementation Method 1
a porous substrate and/or air gaps formed in the substrate so as to improve a heat insulation property
Implementation Method 2
a micro heater configured to locally and uniformly heat only the region of a sensing material
Data Source
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AI summary
A micro heater comprising a substrate including a porous layer having a plurality of vertically-extending pores and a barrier layer positioned on the porous layer and heater electrode formed on the barrier layer.