**1.3 Experiment and results**

We investigated the sensitivity of positive- and negative-type resists in EUV exposures with the system as described above, then performed simulations using the development rate data obtained.

Table 2 gives the conditions of the resists in our experiment.

The negative-type resists examined were the SAL-601 electron beam resist and SU-8 epoxyresin-base chemically amplified resist. The positive-type resists used in our experiment were ZEP-520 non-chemically amplified electron beam resist, EUVR-1 and EUVR-2 acrylic-resinbase resists, and EUVR-3 low-molecular-weight resist.

Approach to EUV Lithography Simulation 173

(a) Discrimination curves for negative-type resists

(b) Discrimination curves for positive-type resists

Fig. 5. Relationship between development rate and exposure dose


Table 2. Conditions of resists in the experiment

Fig. 5.(a) shows discrimination curves for negative-type resists; Fig. 5.(b) shows discrimination curves for positive-type resists.



Table 3. Development characteristics

Table 3. shows the results of development characteristic evaluations.

The results show EUVR-2 provides the highest contrast.

Negative type

SAL-601 Rohm & Hass 105 60 115 60 100

Positive type

520A Nippon Zeon 90 90 95 100 100 EUVR-1 TOK 120 90 120 90 100 EUVR-2 TOK 100 90 110 90 100 EUVR-3 TOK 110 90 100 90 100

Fig. 5.(a) shows discrimination curves for negative-type resists; Fig. 5.(b) shows discrimination

Posi-Type Eth(60) mJ/cm2 γ60 tanθ SAl-601 0.928 -1.445 -2.23 SU-8 0.478 -3.023 -3.73

Nega-Type Eth(60) mJ/cm2 γ60 tanθ ZEP-520A 14.710 1.669 1.90 EUVR-1 2.562 2.325 5.06 EUVR-2 8.574 3.997 30.75 EUVR-3 8.497 1.528 14.53

Table 3. shows the results of development characteristic evaluations.

The results show EUVR-2 provides the highest contrast.

(deg.C)

(deg.C)

Pre-bake PEB

Kayaku 90 90 95 100 100

Pre-bake PEB

Time (s)

Time (s)

(nm) Temp.

(nm) Temp.

Temp. (deg.C)

Temp. (deg.C) Thickness

Thickness

Time (s)

Time (s)

Resist Maker

SU-8 Nippon

Resist Maker

curves for positive-type resists.

Table 3. Development characteristics

Table 2. Conditions of resists in the experiment

ZEP-

Fig. 5. Relationship between development rate and exposure dose

Approach to EUV Lithography Simulation 175

Fig. 7. Simulation results (65-22 nm Isolated patterns)

Fig. 8. Simulation results (32 nm L&S/defocus -0.13~+0.13μm)
