Electron-beam resist novolac-based

From this result on MRS, we expected that a combination of phenolic-resin-based resist and aqueous alkaline developer would lead to etching-type dissolution and non-swelling resist patterns. In this paper, we report on a new non-swelling negative electron beam resist consisting of an epoxy novolac, azide compound and phenolic resin matrix (EAP) and discuss the radiation chemistry of this resist. 

Novolac- or phenolic resin-based resists usually show no pattern deformation induced by swelling during development in aqueous alkaline solution. Examples of such resists are naphtho-quinonediazide/novolac positive photoresists, novolac-based positive electron-beam resist (NPR) (1), and azide/phenolic negative deep-UV resist (MRS) (2). Iwayanagi et al.(2) reported that the development of MRS proceeds in the same manner as the etching process. This resist, consisting of a deep-UV sensitive azide and phenolic resis matrix, is also sensitive to electron-beams. This paper deals with the development mechanism of non-swelling MRS and its electron-beam exposure characteristics. 

Novolac Based Positive Electron Beam Resist Containing a Polymeric Dissolution Inhibitor... 

A novolac-based positive electron beam resist has been investigated for use in direct device... 

Sub-half-micron features could be resolved with deep-UV (35) and electron-beam (36) radiation with wide process latitude and high sensitivity using this chemistiy. An example of the resolution capability is shown in Figure 4. Very sensitive X-ray and e-beam resist formulations based on similar chemistiy using melamine and benzyl alcohol derivatives as crosslinking agents, formulated with onium salt photoacid generators in novolac or poly(hydrotystyrene) binders, have shown 0.2 fim resolution (30, 31). 

Interest in solution inhibition resist systems is not limited to photoresist technology. Systems that are sensitive to electron-beam irradiation have also been of active interest. While conventional positive photoresists may be used for e-beam applications (31,32), they exhibit poor sensitivity and alternatives are desirable. Bowden, et al, at AT T Bell Laboratories, developed a novel, novolac-poly(2-methyl-l-pentene sulfone) (PMPS) composite resist, NPR (Figure 9) (33,34). PMPS, which acts as a dissolution inhibitor for the novolac resin, undergoes spontaneous depolymerization upon irradiation (35). Subsequent vaporization facilitates aqueous base removal of the exposed regions. Resist systems based on this chemistry have also been reported by other workers (36,37). 

H. Ito and E. Flores, Evaluation of onium salt cationic photoinitiators as novel dissolution inhibitor for novolac resin, J. Electrochem. Soc. 135,2322 (1988) H. Ito, Aqueous base developable deep UV resist systems based on novel monomeric and polymeric dissolution inhibitors, Proc. SPIE 920, 33 (1988). T. Aral, T. Sakamizu, K. Katoh, M. Hashimoto, and H. Shiraishi, A sensitive positive resist for 0.1 p,m electron beam direct writing hthography, J. Photopolym. Sci. Technol. 10, 625 (1997). 

Typical optical and laser writer mask-making resists include 895i from ARCH (formerly OCG and now Fuji Films) and iP3500 from TOK for 364-nm exposure systems. Typical resists for electron-beam writers include poly(butene-l-sulfone) (PBS) developed at Bell Laboratories, EBR-900 Ml (novolac-based resist) from Toray Industries, ZEP 7000 from Nippon Zeon, and KRS-XE from IBM. ... 

Resist Chemistry. The basic chemistry of epoxy novolac based chemically amplified resists has been proposed in the past by Stewart et al. (9J. According to this the Bronsted acid generated either photochemically or through electron beam exposure from the onium salt induces acid catalysed polymerization of the epoxy functionality. This mechanism implies that the proton generated by the exposure is actually bound to the polymer. Since the lithography consequences of this mechanism are obvious we decided to seek possible experimental evidence for the proton binding in the resist film under conditions of lithographic interest. 

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