5. Masking for the manufacture of small structures

Plasma-assisted ALD enables lower film deposition temperatures than thermal ALD, and SiO ₂ layers can be deposited at temperatures as low as 50°C.

The race for small dimensions requires the introduction of increasingly sophisticated photolithography techniques, with the development, for example, of an "extreme UV" technique using a wavelength of 13.5 nm. However, this technique is not yet ready, and a two-stage process has been developed which uses current lithography equipment (193 nm wavelength) to process structures with dimensions of less than 50 nm, the dimensions required for memory manufacture in particular. This process uses SiO ₂ deposition at very low temperatures.

For this technique, a photosensitive resin is first deposited and then defined,...