Flow sensor with metal film resistor
AssigneeHitachi, Ltd.
InventorNoriyuki Sakuma
Life of this patent
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Abstract
There is a need for providing a flow sensor with metal film resistor that improves detection sensitivity using a metal film for a resistance heat detector and a resistance temperature detector. The flow sensor with metal film resistor is structured to form a resistance heat detector, a resistance temperature detector for resistance heat detector for measuring temperature of the resistance heat detector, an upstream resistance temperature detector, a downstream resistance temperature detector, and an air resistance temperature detector on a silicon substrate. Plural floating-island insulators are provided for the resistance heat detector and within wiring thereof.
Claims15
A flow sensor with metal film resistor, having a resistance heat detector and a resistance temperature detector provided beside the resistance heat detector, that measures an airflow, comprising:
- a semiconductor substrate;
- a first insulating film formed on the semiconductor substrate;
- and
- a second insulating film formed on the first insulating film and includes a groove whose bottom exposes the first insulating film,
- wherein the resistance heat detector and the resistance temperature detector are formed of a conductive film embedded in the groove;
- and
- wherein a floating-island insulator formed of the second insulating film is provided inside the resistance heat detector.
A flow sensor with metal film resistor, having a resistance heat detector and a resistance temperature detector provided beside the resistance heat detector, that measures an airflow quantity, comprising:
- a semiconductor substrate;
- a first insulating film on the semiconductor substrate;
- and
- a second insulating film that is formed on the first insulating film and includes a groove whose bottom exposes the first insulating film,
- wherein the resistance heat detector and the resistance temperature detector are formed of a conductive film embedded in the groove;
- and
- wherein the second insulating film forming the groove is etched faster than the first insulating film exposed from the bottom of the groove at an etching speed ratio of three or more.
Dependencies are inferred from the claim text.