Deep UV resist

Deep-UV resists comprised of matrix polymers and a 2,6-dinitrobenzyl tosylate photoactive acid generator have been described and compared to previously reported onium salt systems. Although these resists exhibited lower sensitivity than onium salt-based materials, the contrast and processibility are superior. The use of a matrix polymer capable of radiation-induced chain scission improves the sensitivity and allows the 2,6-dinitrobenzyl tosylate acid generator to more nearly... 

The authors would like to acknowledge E. A. Chandross, G. N. Taylor, L. E. Stillwagon and M. Y. Heilman for useful discussions concerning the chemical aspects of this work and to S. Vaydia, V. Pol and J. T. Clemens for input and consultation about the deep-UV resist requirements and process evaluation. 

Copolymer Approach to Design of Sensitive Deep-UV Resist Systems with High Thermal Stability and Dry Etch Resistance... 

In this paper, we report an alternative approach to the design of deep UV resist systems combining the desired properties, which involves copolymerization of methacrylic ester with styrenic comonomer and the use of the acid-catalyzed deprotection chemistry. 

ITOETAL. Copolymer Approach to Design of Deep- UV Resist Systems... 

Figure 6. UV spectra of 1 nm thick films of the alternating copolymer and deep UV resist containing 4.7 wt% of Ph3S+-SbF. ...

The seminal work on deep-UV resist materials which incorporate chemical amplification was started at IBM San Jose s Research Laboratory in 1979 when FrSchet and Willson first prepared poly(4-t-butyloxycarbonyloxy styrene) and end-capped copolymers of o-phthalaldehyde and 3-nitro-l,2-phthalic dicarboxaldehyde. 

Application to Dry-Developed Single-Layer Deep-UV Resists... 

New Negative Deep-UV Resist for KrF Excimer Laser Lithography... 

A photosensitive composition, consisting of an aromatic azide compound (4,4 -diazidodi-phenyl methane) and a resin matrix (poly (styrene-co-maleic acid half ester)), has been developed and evaluated as a negative deep UV resist for high resolution KrF excimer laser lithography. Solubility of this resist in aqueous alkaline developer decreases upon exposure to KrF excimer laser irradiation. The alkaline developer removes the unexposed areas of this resist. 

As for negative deep UV resist, O Toole et al. have exhibited half-micron pattern resolution in 0.5 micron film thickness using the new resist and PIE process (10). The pattern profiles, however, were re-entrant, due to the large photo absorption and the applications to single-layer-resist system have not been presented (11). 

Figure 2 shows the exposure characteristics for azide-styrene resin resist film with an azide concentration from 10 to 40 wt% (based on the styrene resin weight) and Figure 3 shows the contrast of the resist films as a function of the azide concentration. Development was done with a 60s immersion in 0.83% TMAH solution. The styrene resin matrix alone has been found to be a negative deep UV resist. However, rather low contrast (1.48) and low sensitivity (2.5 J/cm2) are observed. The contrast and the sensitivity of the styrene resin is remarkedly increased by adding the azide, as shown in Figures 2 and 3. 

A negative deep UV resist, consisting of a photosensitive 4,4 -diazidodiphenyl methane and a poly-(styrene-co-maleic acid half ester) resin, has been found to meet the requirements needed for KrF excimer laser lithography. 

Frechet, J. M. J. Ito, H. Willson, C. G. "Sensitive Deep UV Resist Incorporating Chemical Amplification," International Conference on Microlithography, Grenoble, France, Oct. 1982. 

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