M-Cresol-benzaldehyde Novolak resin

The preparation method is similar to that for the cresol-formaldehyde Novolak resin with a molar ratio of cresol/benzaldehyde = 1.1 in acidic conditions. We have prepared varieties of substituted m-cresol-benzaldehyde Novolak resins, and 1-, and 2-naphthol-4-hydroxybenzaldehyde Novolak resins in the same manner. Almost all of these benzaldehyde Novolak resins give excellent resist films when spin-coated onto silicon or silicon dioxide substrates after being dissolved, together with a photoactive compound, in a solvent like 2-... 

The UV-absorption spectra of these Novolak resins vary widely depending upon substitution. However, the m-cresol-benzaldehyde Novolak resin is characteristic in its transparency within 300-320 nm in comparison with the cresol-formaldehyde resin. The chlorinated Novolak resin made of 2-chloro-5-methylphenol and formaldehyde has a slightly stronger UV absorption in this wavelength range, but weaker absorption in the range of 250 and 300 nm in comparison with a commercially available cresol-formaldehyde Novolak resin, as shown in Figure 4. 

Figure 4. UV-absorption spectra of Varcum resin (solid line), o-chloro-m-cresol-formaldehyde Novolak resin (long dotted line), and m-cresol-benzaldehyde Novolak resin (short dotted line) 0.32- thick films were...

Figure 5. Resist images made of m-cresol-benzaldehyde Novolak resin with a photoactive compound (15 wt%) 500 mJ/cm2 at 313 nm, and 70 sec in (1 4.5)...

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See also in sourсe #XX -- [ ]

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