Cap, semiconductor device including the cap, and manufacturing method therefor

A cap comprising:

• a through-hole penetrating an upper surface of a silicon substrate and a lower surface of the silicon substrate, the silicon substrate including an inner side surface exposed in the through-hole and an outer side surface located on an opposite side of the inner side surface, the through-hole including an upper end part of the through-hole located on a side of the upper surface of the silicon substrate and a lower end part of the through-hole located on a side of the lower surface of the silicon substrate;
• and
• a silicon dioxide film covering the upper surface of the silicon substrate, the lower surface of the silicon substrate, the inner side surface of the silicon substrate, the outer side surface of the silicon substrate, and the upper end part of the through-hole;
• wherein a part of the silicon dioxide film that covers the upper end part of the through-hole, a part of the silicon dioxide film that covers the upper surface of the silicon substrate, a part of the silicon dioxide film that covers the inner side surface of the silicon substrate, and a part of the silicon dioxide film that covers the outer side surface of the silicon substrate are integrally formed;
• wherein the lower end part of the through-hole is open;
• wherein the part of the silicon dioxide film that covers the upper end part of the through-hole and the part of the silicon dioxide film that covers the inner side surface of the silicon substrate define a recess;
• and
• wherein the part of the silicon dioxide coating film that covers the upper end part of the through-hole is a window part that transmits the light having a predetermined wavelength.