| Example of IMPRIO™ alignment targets |
| | Because the gap between the template and wafer is less than a few microns, the IMPRIO™ systems utilise two layers of overlay patterns, such as box-in-box, vernires, and moiré gratings, as well as precision X, Y, and rotation stages to control layer-to-layer proximity overlay alignment.
The alignment is better than
- 1 micron, 1-sigma for the IMPRIO™ 55
- 500 nm, 3-sigma for the IMPRIO™ 100
- 10 nm, 3-sigma for the IMPRIO™ 250
Since the IMPRIO™ systems use a room temperature, step and repeat process, its overlay alignment is superior to whole wafer thermal imprinting, where large temperature changes significantly degrade performance. |