Electro-thermal converter with long time constant in microsystem technology for thermal breaker
Conception et réalisation d'un convertisseur électro-thermique à grande constante de temps en technologie microsystème pour un disjoncteur thermique (Electro-thermal converter with long time constant in microsystem technology for thermal breaker)
Résumé
Integrated microsystems are becoming more and more important due to miniaturisation of complex systems. Most of the companies study the possibility to translate their products from macroscopic scale to microscopic scale. The purpose of this translation is the possibility to decrease production cost and to increase the performances. This thesis deals with the conception and fabrication of a thermal breaker in microsystems technologies.
A thermal breaker protects an electrical network against over load currents. It measures the thermal power dissipated in wires during a time t. Beyond a reference power, the network is opened. An electro-thermal converter is used to realise this function. The input current is transformed into voltage via heat with an integration effect. The first conversion is made by means of an electrical resistor instead and the second one is made by means of temperature sensor.
The component is a silicon mass placed in high vacuum, supported by silicon oxide arms. The silicon mass is used as a thermal capacitor (heat storage) and the oxide arms behave as thermal resistors. The combination of previous properties defines the time constant of the converter (t). The mechanical characteristics are not adequate for an industrial environment, so a new solution has been developed. This solution is called the electro-thermal converter with thermal barriers.
Both components have been fabricated with a CMOS process and a front side bulk micromachining. An anisotropic etch solution has been developed and characterised. This solution is TMAH 10%.
A thermal breaker protects an electrical network against over load currents. It measures the thermal power dissipated in wires during a time t. Beyond a reference power, the network is opened. An electro-thermal converter is used to realise this function. The input current is transformed into voltage via heat with an integration effect. The first conversion is made by means of an electrical resistor instead and the second one is made by means of temperature sensor.
The component is a silicon mass placed in high vacuum, supported by silicon oxide arms. The silicon mass is used as a thermal capacitor (heat storage) and the oxide arms behave as thermal resistors. The combination of previous properties defines the time constant of the converter (t). The mechanical characteristics are not adequate for an industrial environment, so a new solution has been developed. This solution is called the electro-thermal converter with thermal barriers.
Both components have been fabricated with a CMOS process and a front side bulk micromachining. An anisotropic etch solution has been developed and characterised. This solution is TMAH 10%.
Les microsystèmes connaissent depuis une dizaine années un développement important grâce à leur pouvoir de miniaturisation des systèmes complexes. A l'heure actuelle un grand nombre d'entreprises étudie la possibilité de faire passer leurs produits de l'échelle macroscopique à l'échelle microscopique. Cette translation d'échelle a pour but de réduire les coûts de production et d'augmenter les performances. Dans cette optique, ce travail de thèse a étudié une solution de disjoncteur thermique en technologie microsystème.
Le disjoncteur thermique protège les réseaux électriques contre des surcharges de courant en mesurant l'énergie qui s'écoule dans les fils
pendant une durée ? Au delà d'une énergie de seuil, le réseau est ouvert. Le composant microsystème réalisant cette fonction est un convertisseur électro-thermique à grande constante de temps.
Le disjoncteur thermique protège les réseaux électriques contre des surcharges de courant en mesurant l'énergie qui s'écoule dans les fils
pendant une durée ? Au delà d'une énergie de seuil, le réseau est ouvert. Le composant microsystème réalisant cette fonction est un convertisseur électro-thermique à grande constante de temps.
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