Naphthoquinone diazides

The process by which a solubility differential between exposed and unexposed areas occurs is well known (74). Photodegradation products of the naphthoquinone diazide sensitizer, eg, a l,2-naphthoquinonediazide-5-sulfonic acid ester (11), where Ar is an aryl group, to an indene carboxylic acid confers much increased solubility in aqueous alkaline developer solutions. 

The y-nitrogen atom of a sulfonic acid azide is electrophilic and reacts in an electrophilic aromatic substitution with an activated benzene or naphthalene derivative, e.g., a phenoxide ion, forming a l-tosyl-3-aryltriazene (2.47). The 1,4-quinone diazide is obtained by hydrolysis (Scheme 2-30, Tedder and Webster, 1960). The general applicability of this reaction seems to be doubtful. With 1-naphthol the 1,2-naphthoquinone diazide was obtained, not the 1,4-isomer. 

In the case of the 2,1-naphthoquinone diazide Zeller (1975a) was able to demonstrate clearly that the electron impact induced loss of N2, CO, and H is a stepwise process. The question of the possible involvement of a naphthooxirene intermediate (4.25) was clearly answered by mass spectrometry of the l-13C-2,1-naphthoquinone diazide (4.24). The [M - N2 - CO]+ radical ion (4.26) does not contain 13C, and therefore no naphthooxirene is formed (Scheme 4-4). 

For positive resists, mixtures of 1,2-naphthoquinone diazides with phenolic resins, mainly the polymer from 3-cresol and formaldehyde (Novolac), are used. 

An interesting suggestion was made by Levine in 1969. He supposed that the ketene formed photolytically from 1,2-naphthoquinone diazide could react with unreacted 1,2-naphthoquinone diazide to form a spirolactone-type addition product. This suggestion was tested experimentally almost twenty years later by Huang and Gu (1988). They irradiated 1,2-naphthoquinone diazide in dioxane in the presence of pyrene as sensitizer with a high-pressure mercury vapor lamp (Scheme 10-103). They did indeed obtain the spirolactonespiro(naphtho[4,5 2/,l/]furano-2-one)-3 T -inde-... 

Naphthoquinone diazides 32, 284ff., see also Quinone diazides 2,3-Naphthotriazole, formation 132 f. Negations, psycholinguistics of 215 Nesmeyanov reactions 273 ff. Nicotinamide-adenine nucleotide (NAD+) 328 f. 

Figure 17 shows the sensitivity curves of the resist containing PM-5(run-6)(75 weight%) and 5-naphthoquinone diazide sulfonate of 2,3,4-trihydroxybenzophenone(25 weight%). The average esterification ratio of the photoactive compound was 2.5 units per three OHs in the benzophenone. The y value was 1.6 and the sensitivity was 90mJ/cm2 when developed with 0.34% TMAH aqueous solution for 120 sec at 20°C. The resist containing M-5(run 3)... 

The Wolff rearrangement is well known as a reaction of diazo ketones, i.e. of diazoalkanes with a carbonyl group in a-position. Reaction 34 demonstrates that diazotized aminonaphthols are mesomeric with naphthoquinone diazides (48b) and that they have therefore also the character of quinonoid diazo ketones (see also Section II.C of this chapter). Wolff rearrangements take place also thermally and catalyzed by silver ions. 

Roland, B. Vandendriessche, J. Lombaerts, R. Denturck, B. Jakus, C. Thermal crosslinking by unexposed naphthoquinone diazides as diffusion inhibition mechanism in the DESIRE process. Proc. SPIE 1988, 920, 120-127. 

Koshiba, M. Murata, M. Matsui, and Y. Harita, Thermally induced and base catalyzed reac tions of naphthoquinone diazides, Proc. SPIE 920, 364 (1988). 

The membrane model, proposed by Arcus, treats the interface between the resin and developer as a partially semipermeable membrane that may differentiate between the ions of aqueous developers due to variations in size, composition, and charge. .. the membrane properties can be modified by chemical treatments, changes in concentration. .. and most importantly by the photochemistry of the included naphthoquinone-diazide. This model appears to account for a great... 

In order to understand the changes, it is necessary first to know the components of the resist and the chemistry of the exposure step. For positive photoresists, the mechanism was elucidated by Pacansky and Lyerla (14). Typical resists are a solution of a naphthoquinone diazide photoactive compound (PAC) and a cresol formaldehyde novolak resin in one or more high boiling point industrial solvents. The number average molecular weight of the resin is quite low, on the order of 1000, with a polydispersity of about 10 (13). During the normal exposure step, the PAC, in the presence of water, absorbs light and is transformed into a... 

In the context of this technology Siis investigated already in 1944 the photolysis of o-quinone diazides. Equation 34 shows the photolysis sequence for 1,2-naphthoquinone diazide (48) formed in the diazotization of 2-amino-1-naphthol. The product of the pho-tolytic step is a ketocarbene (49), which undergoes a Wolff rearrangement to a ketene (50). In the presence of water indene-3-carboxylic acid (51) is formed this compound is highly soluble in water and can be removed in the development step. The reaction steps of equation 34 were investigated in recent years intensively, mainly by Canadian chemists (see also the monograph of Tidwell on ketenes ). 

Enhancement of solubility by a photoinduced molecular rearrangement (e.g., naphthoquinone diazide in a novolac binder resin). 

FIGURE 16.4 Reverse imaging using a Novolae-naphthoquinone diazide resist mixture exposed to UV radiation. (From Bowden, M.J. and Turner, S.R, Exls., Electronic and Photonic Applications of Polymers, American Chemical Society, 1988. With permission.). 

Positive polyimide resists have also been developed. One example starts from a solnble polymer [60] with a formulation analogons to a novolac positive resist o-naphthoquinone diazide was used as a photoreactant linked to the polymer (Figure 6.25). 

Compounds have been studied having 1,2- and 1,4-benzo- and naphthoquinone diazide groups.They absorb at 2173-2014 and 1642-1562 cm due to the asymmetric CNN stretch and the C=0 stretch, respectively. 

Abstract The present paper describes chemistry of naphthoquinone diazide... 

Although thermal and base catalyzed reactions of NQD are becoming important, there is limited information on these reactions which take place in the positive photoresist. The authors carried out model experiments using 1,2-naphthoquinone diazide-5-sulfonyloxybenzene (DAM) and p-cresol. DAM was selected as a model for the PAC and p-cresol was a model for the novolak resin. These two compounds were mixed together and reacted either by heating or in an alkaline developer which is 2.38wt% tetramethylammonium hydroxide (TMAH) aqueous solution. 

Formation of the protective layer which is rich in naphthoquinone diazides. 

Chemistry of naphthoquinone diazide was reviewed on the three different types of its reactions i.c., photochemical, thermal and base catalyzed reactions. Mechanisms of the several novel resist processes were elucidated based on these reactions. 

Rosenfeld, A., Mitzner, R., Baumbach, B., and Bendig, J., Laser photolytic and low temperature investigations of naphthoquinone diazides in Novolak films, /. Photochem. Photobiol. A Chem., 55, 259, 1990. 

Bendig, J. and Mitzner, R., Laser photolysis of naphthoquinone diazide in cyclohexane — Two-laser chemistry, Ber. Bunsenges. Phys. Chem., 98, 1004-1008, 1994. 

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