High aspect ratio nanovolume glass cell array fabricated by area-selective silicon electrochemical etching process

Fabrication of arrays of high aspect ratio nanovolume glass (SiO₂) cells or "test tubes" by using electrochemical process was attempted, which could be applied to various micro scale and nano scale systems. By applying a shield mask to the backside of the wafer to control the illumination condition of the light, which generates the hole, area selective anodization process was developed to form arrays of the straight micropores at the selected region of the Si surface. Then the surface of the micropores was thermally oxidized to form SiO₂ layer and bulk Si region was partially removed by alkaline etching to expose the array of freestanding, SiO₂ hollow tubes.