on the substrate fig5 b is a cross sectional view showing the main portion of the fabricating process after an electrode etching photoresist pattern has been formed fig5 c is a cross sectional view showing the main portion of the fabricating process after au wet etching has been conducted fig5 d is a cross sectional view showing the main portion of the fabricating process after ti pt dry etching has been conducted fig5 e is a cross sectional view showing the main portion of the fabricating process after a photoresist has been stripped referring to fig5 a ti pt au is deposited in a range of 10 nm to 1 u03bcm as the electrode layer 20 in this example 150 nm 40 nm 750 nm is deposited respectively after a photoresist pattern 70 has been formed in fig5 b au is etched with an aqueous solution of iodine and ammonium iodide in fig5 c in this example the aqueous solution containing the aqueous solution of iodine and ammonium iodide can selectively etch au or pt the etching does not stop at a just etch but stops after etching is advanced up to a lower portion of the photoresist 70 by about 1 to 3 u03bcm in fig5 d ti pt is etched by the aid of the same photoresist through ion milling in this example etching conducted by ion milling is anisotropic and no etching is advanced in a lateral direction as a result as shown in fig5 e the entire outer periphery of the electrode layer 20 is of a two stage.