Table 2. Characteristics of Two Production Steppers.
| |
light
at film surface |
||||||
|---|---|---|---|---|---|---|---|
| light
source |
fluence
per pulse |
||||||
| model | frequency (kHz) | power (W) | pulse energy (mJ) | intensity (W/cm2) | (mJ/cm2) | (mJ/die)c | stepping time (ms) |
| PAS5500/1150Ca | 4 | 20 | 5 | 1.1 | 0.275 | 2.4 | 560f |
| NXT1980Dib | 6 | 120d | 20 | 6.6e | 1.1 | 9.44 | 132g |
Specifications from https://www.asml.com/products/systems/pas-5500/en/s46437?dfp_product_id=1964.
Specifications from https://www.asml.com/products/systems/twinscan-nxt/en/s46772?dfp_product_id=10567.
For a die size of 2.6 cm × 3.3 cm = 8.58 cm2 as stated in the manufacturer’s specifications.
Reference (19) authored by Cymer, a subsidiary of AMSL.
Aerial intensity for NXT is not given by the manufacturer. Instead, losses in the imaging optics are assumed identical to the PAS stepper, giving an aerial intensity 6× larger than the PAS.
Stepping time from specified 135 wafers/h (46 dies/wafer) at an exposure dose of 20 mJ/cm2 (that takes 18 ms).
Stepping time from specified 275 wafers/h (96 dies/wafer) at an exposure dose of 30 mJ/cm2 (that takes 4.5 ms).