Gas sensor element and manufacturing method of the same

摘要

Provided herein are a gas sensor element in which deformation of a sensitive portion due to stress may be reduced and a method of manufacturing the gas sensor element. A base insulating layer 9 including a heater wiring pattern 19 is formed on a front surface 3A of a support 3. The base insulating layer 9 includes a fixed portion 15 fixed to the front surface 3A of the support 3, and a nonfixed portion 17 located over an opening portion 5. A cavity portion 7 having the opening portion 5 is formed in the support 3. An electrode wiring pattern 27 and a sensitive film 31 are formed over a central portion 21 of the nonfixed portion 17 of the base insulating layer 9. The nonfixed portion 17 includes the central portion 21 and a plurality of connecting portions 23 connecting the central portion 21 and the fixed portion 15. Four connecting portions 23 each include a base portion 33 and an extended portion 35. The base portion 33 of each connecting portion 23 is formed to extend along an edge portion 5A of the opening portion 5. Each extended portion 35 is formed to extend from the base portion 33 to the central portion 21 to be connected to the central portion 21. The connecting portions 23 are formed such that the maximum width W1 of each base portion 33 is larger than the maximum width W2 of each extended portions 35.

主权项

1. A gas sensor element comprising:
a support formed of a silicon monocrystalline substrate and having a front surface and a back surface facing each other in a thickness direction of the support, wherein a cavity portion is formed in the support, having an opening portion opened at least in the front surface; a base insulating layer formed by laminating a lower insulating layer made of silicon nitride and silicon oxide and an upper insulating layer made of silicon nitride oxide, the base insulating layer including: a fixed portion having a back surface fixed to the front surface of the support; and a nonfixed portion unitarily formed with the fixed portion and located over the opening portion of the support; a heater wiring pattern formed between the lower insulating layer and the upper insulating layer and including an electric heater portion formed on and in contact with a central portion of the nonfixed portion, the central portion having a shape as a circular plate; an electrode wiring pattern formed on a surface of the upper insulating layer and including a detecting electrode portion at the nonfixed portion; and a sensitive film formed by application over the detecting electrode portion at the central portion of the nonfixed portion; and, the nonfixed portion of the base insulating layer including the central portion and four connecting portions connecting the central portion and the fixed portion; the connecting portions each including a base portion extending along an edge portion of the opening portion and an extended portion extending to be connected to the central portion, wherein: the base portions of the four connecting portions are located at four corners of the opening portion, and the base portions are each formed to extend across two sides out of four sides forming the edge portion of the opening portion, each two sides forming one corner of the opening portion corresponding to one base portion; and, edge portions of the base portions of the four connecting portions facing the central portion follow a virtual circle centering around the center of the central portion.