Wet development

The first example of resist relief image formation in the absence of a wet developing step was reported by Bowden and co-workers in 1974 60). These workers reported that exposure of certain poly (olefin sulfones) to electron beam radiation resulted in spontaneous relief image formation. If the films were cast thin enough and the substrates were heated, it was possible to produce clean images in the resist films by exposure alone, thereby avoiding a wet development step. 

THE PHASE SEPARATED COLUMNAR STRUCTURE CAUSES ANISOTROPIC ETCHING, MAKING WET DEVELOPING, WITHOUT UNDERCUTTING POSSIBLE. 

Recently it was disclosed in a Japanese patent that the copolymers of hexanal with propanal, butanal and isobutanal could be used as self-developing X-ray resists of 200 — 400 mJ/cm2 sensitivity (32). Our poly(ethanal-co-butanal) showed the sensitivity of 30 mJ/cm2 on the exposure to X-ray radiation without requiring a wet development process (Table VIII). Other copolymers also functioned as a positive self developing X-ray resist. 

Figure 12. Electron beam imaging of poly(di-n-pentylsilane) (0.14 ym) coated over 2.0 xm of a hard-baked AZ-type photoresist exposed at 20 iClcm and wet developed. Pattern transfer was by O2-RIE.

In this chapter the properties of organic molecules which are potentially useful as archival digital optical memory media, mainly erasable media, will be described. The memory media which require wet development/fixing processes will not be mentioned. Photopolymers and photoresists are also beyond the scope of this chapter. 

Fig. 82 SEM pictures of the CM polymer after cross-linking. Top after wet development in CHC13 middle structuring of the cross-linked and wet developed polymer (from top SEM) (1 pulse with 7.9 J cm 2 at 308 nm) bottom inverse processing, i.e., first laser structuring, then cross-linking and wet development. REPRINTED WITH PERMISSION OF [Ref. 120], COPYRIGHT (2000) Wiley-VCH Verlag GmbH...

Polycarbonates based on 2-cyclohexen-l,4-diol and a dihydroxy compound liberate benzene through aromatization, a dihydroxyl compound, and carbon dioxide, upon acidolysis [343]. The low volatility of the dihydroxyl compound hampers complete development by heating alone and necessitates wet development. 

Semi-Dry Bilayer Lithography (Wet Development/02 RIE Pattern Transfer)... 

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