Holed MEMS Microheater for Gas Sensor Power and Stability
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Solution Overview
Problem
Existing MEMS type semiconductor gas sensors are structurally, mechanically, and electrically weak under sudden impacts and have high power consumption, making them unsuitable for portable terminals and ubiquitous sensor networks.
Innovation Solution
The development of an MEMS type semiconductor gas sensor using a microheater with many holes, where membranes and heat emitting resistors are etched with a predetermined thickness to enhance structural and mechanical stability while reducing power consumption, combined with a method for manufacturing this design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the substrate is etched completely through to thermally separate the heater part, then power consumption is reduced, but process cost increases and manufacturing complexity increases
Solution Approach 1:
The substrate etching is segmented into two stages: first etching through the heater region to create thermal isolation, then selectively removing the central portion of the substrate. This segmentation allows thermal separation to be achieved without requiring complete through-etching of the entire substrate, thereby reducing process complexity and cost while maintaining power consumption benefits.
Solution Approach 2:
The etching process applies local quality by differentiating between regions: the heater region is fully etched through for thermal isolation, while the central substrate region is selectively removed to create the hollow structure. This localized approach optimizes both thermal performance and manufacturing efficiency without requiring uniform through-etching across the entire substrate.
2Ease of manufacture
If only part of the substrate thickness is etched, then process cost is reduced, but the membranes become weak and structural stability deteriorates
Solution Approach 1:
The etching process is segmented into selective regions: the heater area is fully etched through for thermal isolation, while the central substrate is partially etched to create a hollow structure. This segmentation maintains membrane strength in non-heater regions while achieving thermal separation where needed, resolving the contradiction between cost reduction and structural strength.
Solution Approach 2:
Different etching depths are applied to different regions: full through-etching in the heater region for thermal isolation, and partial etching in the central region for structural optimization. This local quality approach ensures membranes retain sufficient strength while reducing overall material usage and process cost.
3Strength
If membranes are connected to the substrate without holes, then mechanical strength is maintained, but power consumption increases due to thermal connection
Solution Approach 1:
The membrane-substrate connection is segmented into two functional zones: the heater region where complete etching creates thermal isolation (reducing power consumption), and the central region where selective etching creates a hollow structure that maintains mechanical support. This segmentation allows thermal isolation without completely disconnecting the membrane structure.
Solution Approach 2:
Different thermal isolation strategies are applied locally: complete through-etching in the heater region to eliminate thermal connection and reduce power consumption, and selective central etching to maintain structural integrity. This local differentiation resolves the contradiction between mechanical strength and power consumption.
4Measurement precision
If the sensor uses bulk type design with heater, then sensing characteristic is improved, but power consumption becomes large and portability is reduced
Solution Approach 1:
The bulk-type sensor structure is segmented by selectively removing the central substrate to create a hollow configuration. This segmentation reduces the thermal mass and heat capacity of the substrate, allowing the heater to reach operational temperature faster and consume less power, while maintaining the sensing characteristics of bulk-type sensors.
Solution Approach 2:
The substrate structure is modified with local quality by creating a hollow central region while preserving the heater region integrity. This local modification reduces overall thermal mass and power consumption while maintaining the sensing performance characteristics associated with bulk-type sensors, enabling portability without sacrificing measurement precision.
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 sensor achieves increased lifespan and stability under sudden impacts with reduced power consumption, enabling long-term operation in various environments and extreme conditions.
Implementation Method 1
a heat emitting resistor formed on the second membrane and having many holes
Implementation Method 2
when a gaseous component is adsorbed onto the surface of a semiconductor or reacts with adsorbed gas such as oxygen which was adsorbed in advance
Implementation Method 3
electrons are transferred between adsorbed molecules and the semiconductor surface, and as a result, conductivity and surface potential of the semiconductor are changed
Data Source
AI summary
Disclosed are an MEMS type semiconductor gas sensor using a microheater having many holes and a method for manufacturing the same. The MEMS type semiconductor gas sensor includes: a substrate of which a central region is etched with a predetermined thickness; a second membrane formed at an upper portion of the central region of the substrate and having many holes; a heat emitting resistor formed on the second membrane and having many holes; a first membrane formed on the second membrane including the heat emitting resistor and having many holes; a sensing electrode formed on the first membrane and having many holes; and a sensing material formed on the sensing electrode.