Deep-UV imaging

H. Saijo, Y. Suzuki, M. Shiojiri, Deep UV imaging by spectrometric fuU-colour cathodolumi-nescence microscopy. J. Phys. Conf. Sen 241, 012079 (2010)... 

The deep UV induced reactions appear to be slightly different from X-ray and EB induced reactions. Deep UV exposure in air can induce an increase in solubility of SPP, indicating that indenecar-boxylic acid is produced. IR spectra of SPP exposed to deep UV are shown in Figure 11. In this case, we used a mono-functional dissolution inhibitor, tert-amylphenol diazonaphthoquinone sulfonyl ester, instead of a multi-functional sensitizer, DNQ, because the IR spectrum of a mono-functional ester is easier to interpret than that of DNQ. The SPP containing this mono-functional ester also exhibits an image reversal reaction with almost the same characteristics as the SPP with DNQ. 

Preliminary Examination of PATE Imaging Characteristics. The data herein have shown that PATE resins are easily photolyzed in the deep UV region to form crosslinked films which are of sufficient integrity for photoresists. However, in addition to these film performance properties, a potential resist material must meet other equally important criteria. For example, the masked (unphotolyzed) portion of the resist film must be removed prior to etching, without damage to the cured film. Also, the cured films must withstand an etchant bath. Therefore, since PATE resins seem to meet the necessary requirements of solubility and solvent resistance, investigation of performance under crude simulated processing conditions was undertaken. 

The schematic processing steps for the two-layer deep-UV PCM system are shown in Table III for near-UV and e-beam exposures, resulting in capped and uncapped profiles respectively. Step 5a is required only for near-UV exposures to average out optical interference effects discussed in Section 6.2.a. Step 6a is used to enhance the AZ to PMMA adhesion and cap retention. Figure 15 shows uncapped 1 - nm lines in a 2 - /im thick PMMA layer. Figure 16 shows the capped image with 0.3 fim AZ on 2 -iLim PMMA. The AZ layer was delineated by a 30 - /iC/cm 25 - keV e-beam in both cases. 

Figure 15. Uncapped resist image obtained with a two-layer deep-UV PCM system. The 0.85-um wide PMMA lines were 1.9-fim thick separated by 2.4 ixm. A 0.2-um AZ1350J PCM was used.

Figure 16. Capped resist image obtained with an identical two-layer deep-UV PCM system as in Figure 13. The AZ layer was 0.3-fim thick on...

P(VMS) layer on 3.0 ixm of AZ1350J. The e-beam dosage used was 2.0 uCIcrr . (b) Similar P(VMS) features on 2.5 fim of AZ1350J. The imaging layer was delineated with 220-nm deep-UV light. (Reproduced with permission from Ref. 19.)... 

Figure 24. Uncapped images delineated with the Novolak/PMMA deep-UV PCM system. A GCA Mann DSW4800 aligner with 0.28-NA and 436-nm wavelength was used. The smallest openings are of 0.8 /iw nominal dimension. (Reproduced with permission from Ref. 46.)...

Figure 40. Uncapped resist image showing insufficient deep UV absorption...

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