Solubility in aqueous alkaline solution

Positive-Tone Photoresists based on Dissolution Inhibition by Diazonaphthoquinones. The intrinsic limitations of bis-azide—cycHzed mbber resist systems led the semiconductor industry to shift to a class of imaging materials based on diazonaphthoquinone (DNQ) photosensitizers. Both the chemistry and the imaging mechanism of these resists (Fig. 10) differ in fundamental ways from those described thus far (23). The DNQ acts as a dissolution inhibitor for the matrix resin, a low molecular weight condensation product of formaldehyde and cresol isomers known as novolac (24). The phenoHc stmcture renders the novolac polymer weakly acidic, and readily soluble in aqueous alkaline solutions. In admixture with an appropriate DNQ the polymer s dissolution rate is sharply decreased. Photolysis causes the DNQ to undergo a multistep reaction sequence, ultimately forming a base-soluble carboxyHc acid which does not inhibit film dissolution. Immersion of a pattemwise-exposed film of the resist in an aqueous solution of hydroxide ion leads to rapid dissolution of the exposed areas and only very slow dissolution of unexposed regions. In contrast with crosslinking resists, the film solubiHty is controUed by chemical and polarity differences rather than molecular size. 

Propylthiouracil. This compound is a white, powdery, crystalline substance of starch-like appearance with a bitter taste. It is slightly soluble in water, chloroform, and ethyl ether, sparingly soluble in ethanol, and soluble in aqueous alkaline solutions (53). An extensive compilation of its chemical, spectral, and chromatographic properties is available (43). It is assayed titrimetrically with NaOH (53). 

TI4SCI4 and T SeCh melt at 440 and 442°C, respectively. They can be distilled between 650 and 700°C without decomposition. They are insoluble in H2O and organic solvents, but soluble in aqueous alkaline solutions. With cone, acids, decomposition takes place. The electric conductivity has been determined to be 1.4-10 and 2.1-10 fl cm for TI4SCI4 and TUSeCU, respectively. The probable structural formula is Tl3(TlCl4Y). The compounds thus, presumably, consist of Tli,4Cl4,4Y2/8 octahedra that are interconnected by the chalcogen atoms to linear chains (321). 

Organic solvents Slowly soluble in aqueous alkaline solutions practically insoluble in nonpolar organic solvents3 Very slightly soluble in cone HCL and HN03a No data... 

Solubility practically insoluble in acetone, ethanol, and water soluble in aqueous alcohol solutions, aqueous acetone solutions (60-80% v/v), and glycols. Also soluble in aqueous alkaline solutions of pH 11.5 and above. 

PHYSICAL PROPERTIES white crystalline powder odorless very hard, about 8.8 on Moh s scale practically insoluble in water, non-polar organic solvents slowly soluble in aqueous alkaline solution, forming hydroxides very slightly soluble in acid, alkali soluble in cold water insoluble in hot water MP (2000°C, 3632°F) BP (2980°C, 5396°F) SG (4.0) DN (4.0 g/ml at 20°C) ST (NO DATA) VS (NO DATA) Cpmean (795.6J/kg-K) HV (NO DATA) VD (NO DATA) VP (ImmHg at 2158°C). 

Yellowish crystalline solid melts at 112°C (233°F) sublimes when heated slowly and carefully almost insoluble in cold water, soluble in alcohol, ether, acetone, pyridine, and most organic solvents, soluble in aqueous alkaline solutions. 

Novolac polymers are soluble in a variety of common organic solvents. Resist films are typically cast from organic solutions (propylene glycol monomethyl ether acetate, or PGMEA, is a common solvent) to form isotropic, glassy, thin films. These polymers are also soluble in aqueous alkaline solutions due to the presence of the acidic phenolic functionalities on the polymer backbone. It is this base solubility that is exploited in the development process. In order to print a relief image in a photoresist, it must be possible to modify the dissolution rate of the resist upon exposure to radiation. It is not the... 

The advent of 85% kraft lignin-based thermoplastics was an important development since it had been assumed until then that polymeric materials with such high lignin contents would be extremely weak — if, indeed, they were capable of retaining any measurable cohesiveness at all. However, the kraft lignin components in these new thermoplastics were still partially soluble in aqueous alkaline solution, and thus alternative formulations were sought to obviate dissolution in aqueous solutions of any kind. 

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