X-ray mask, EB mask, Photo mask

NTT-AT has accumulated various key technologies for the development and production of ultra fine patterning products. These technologies have been cultivated through the development of X-ray mask, one of the key components for X-ray lithography which has been the key lithography method for a long time as part of the next generation LSI production.

Features

• Able to replicate small patterns (pattern feature size : smaller than 0.1µm)
• Achieving highly precise pattern position accuracy due to SiC membranes

Structure

Typical specifications	Mask image
Structure Ta patterns on membrane Absorber Ta 300nm thickness Stress ~ 0MPa Membrane SiC or SiN   2µm thickness Stress 100MPa ~ 200MPa 20 ~ 30mm square Minimum pattern width 50nm Pattern position accuracy 3σ < 30nm

• Stencil mask using ultra thin SiC membrane

Fabrication example

Typical specifications	Mask image
Structure SiC stencil structure Membrane SiC 300nm thickness Stress 100MPa ~ 200MPa 3mm square × 25 fields Minimum pattern size 50nm
Mask pattern (SEM)
70nm hole pattern