Thermal Air Flow Sensor

摘要

A thermal air flow sensor that produces less measurement error is provided. The thermal air flow sensor includes: a semiconductor substrate; a heating resistor, resistance temperature detectors, and an electrical insulator that includes a silicon oxide film, wherein the heating resistor, the resistance temperature detectors, and the electrical insulator are formed on the semiconductor substrate; and a diaphragm portion formed by removing a portion of the semiconductor substrate. The heating resistor and the resistance temperature detectors are formed on the diaphragm portion. The thermal air flow sensor further includes a silicon nitride film formed as the electrical insulator above the heating resistor and the resistance temperature detectors. The silicon nitride film has steps conforming to the patterns of the heating resistor and the resistance temperature detectors. The silicon nitride film has a multilayer structure.

主权项

1. A thermal air flow sensor comprising:
a semiconductor substrate; a heating resistor, resistance temperature detectors, and an electrical insulator that includes a silicon oxide film, wherein the heating resistor, the resistance temperature detectors, and the electrical insulator are formed on the semiconductor substrate; and a diaphragm portion formed by removing a portion of the semiconductor substrate, the heating resistor and the resistance temperature detectors being formed on the diaphragm portion, and the thermal air flow sensor further comprising a silicon nitride film formed as the electrical insulator above the heating resistor and the resistance temperature detectors, wherein the silicon nitride film has steps conforming to the patterns of the heating resistor and the resistance temperature detectors, and wherein the silicon nitride film has a multilayer structure.