| 摘要 |
PROBLEM TO BE SOLVED: To provide a film formation method of a heater for a limiting current type oxygen sensor for reducing the variation in heater resistance without increasing costs, and to provide a mask for sputter used for the film-forming method when forming a plurality of heaters on a plurality of porous oxygen gas speed-control body substrates acquired from one mask substrate to be subjected to film formation by sputtering. SOLUTION: By utilizing the film thickness distribution tendency in a plurality of heaters that are subjected to film formation by sputtering, film formation is conducted so that the width of the plurality of heaters becomes wider from the center of a mask substrate, that is subjected to film formation to the periphery. In this manner, by utilizing the film thickness distribution tendency through sputtering, film formation can be made with an optimum heater width quantitatively, thus accurately reducing the variations in the resistance among the plurality of heaters, and reducing also the variation of the output characteristics in the limited current type oxygen sensor. |
