dry etching such as reactive ion etching rie the size of the opening 12 formed is determined by taking into consideration the size of the device to be joined to a cover then as shown in fig1 b the silicon wafer 11 is joined to a glass sheet 13 to be integrated therewith the joining may be performed using methods such as anodic bonding or the like an adhesive may also be used to perform the joining next as shown in fig1 c a light interrupting film 14 is formed on the inner surface of the opening 12 of the silicon wafer 11 alternatively a light interrupting film 14 may be formed after the step of fig1 a i e the formation of the openings 12 in the silicon wafer 11 the light interrupting film 14 may be formed by for example depositing a cro 2 cr thin film by sputtering or evaporation and patterning the deposited film film thickness of the cro 2 cr thin film formed may be generally of the order of 0 2 u03bcm the light interrupting film 14 may be formed by patterning it so as to cover a part of glass sheet surface in the region of the opening 12 as shown in.