Resist acetal-protected chemical

S Acetal- and ketal-protected chemical amplification resiste... 

The concept of acid labile crosslinked units in polymers for positive DUV resist was evaluated with poly-(4-hydroxystyrene/4-vinylcyclohexanol) and implemented on a poly-4-hydroxystyrene backbone. The principle to increase the molecular weight by a transacetalization reaction was used to improve acetal protected phenolic resins for advanced chemically amplified resists. The polymer chains were linked via diols with acetal bridges. This type of linkage can be applied to a wide range of phenolic polymer binders. Resolution and thermal stability of the photoresist patterns were improved. Gel permeation chromatography and dissolution rate measurements prove that the crosslinked units remain essentially intact in the unexposed areas, thus enhancing... 

A chemically amplified deep UV photoresist system based on acetal chemistiy is reported. Acetal-protected pol vinylphenols) were prepared either by free radical polymerization of the monomers or chemical modification of poly(vinylphenol). In the presence of an add as a catalyst, the polymers thermally decomposed to aqueous base soluble po vinylphenol) and some small molecules. Therefore, the resists were formulated with the acetal-protected polymers and a photoadd generator such as triphei lsulfonium hex-afluoroantimonate. Positive-tone image could be resolved 1 exposing the resist film in deep UV region, post-baking, and developing in tetramethylam-monium hydroxide solutions. 

Vinyl lacquers are used mainly where a high degree of chemical resistance is required these lacquers are based on vinyl chlorides and vinyl acetates. Acrylic lacquers are based on methyl methacrylate and methyl acrylate polymers and copolymers. Other esters of acrylic and methacrylic acid also may be used to make nonconvertible film formers. Judicious selection of these acrylic acid or methacrylic acid esters allows one to produce film formers with specifically designed properties such as hardness, flexibility, gloss, durability, heat, and chemical resistance. Acrylic lacquers, however, are not noted for their water resistance. The principal uses of acrylic-type lacquers are fluorescent and metallic paints, car refinish applications, clear lacquers and sealers for metals, and protective coatings for aircraft components and for vacuum-deposited metals, as well as uses in pigmented coatings for cabinets and appliances. 

PVCA is a copolymer of vinyl chloride and vinyl acetate. It is a colorless thermoplastic solid with good resistance to water as well as concentrated acids and alkalis. It is obtainable in the form of granules, solutions, and emulsions. Compounded with plasticizers, it yields a flexible material superior to rubber in aging properties. It is widely used for cable and wire coverings, in chemical plants, and in protective garments. 

Pure lead has low creep and fatigue resistance, but its physical properties can be improved by the addition of small amounts of silver, copper, antimony, or tellurium. Lead-clad equipment is in common use in many chemical plants. The excellent corrosion-resistance properties of lead are caused by the formation of protective surface coatings. If the coating is one of the highly insoluble lead salts, such as sulfate, carbonate, or phosphate, good corrosion resistance is obtained. Little protection is offered, however, if the coating is a soluble salt, such as nitrate, acetate, or chloride. As a result, lead shows good resistance to sufuric acid and phosphoric acid, but it is susceptible to attack by acetic acid and nitric acid. 

Acetals and ketals have attracted a great deal of attention recently as protecting groups of PHOST due to their lower activation energies of deprotection than fBOC and terf-butyl esters. While the majority of chemical amplification resists require PEB to accelerate acid-catalyzed reactions, deprotection of ac-... 

A new type of copolymer resist named ESCAP (environmentally stable chemical amplification photoresist) has recently been reported from IBM [163], which is based on a random copolymer of 4-hydroxystyrene with tert-butyl acrylate (TBA) (Fig. 37), which is converted to a copolymer of the hydroxystyrene with acrylic acid through photochemically-induced acid-catalyzed deprotection. The copolymer can be readily synthesized by direct radical copolymerization of 4-hydroxystyrene with tert-butyl acrylate or alternatively by radical copolymerization of 4-acetoxystyrene with the acrylate followed by selective hydrolysis of the acetate group with ammonium hydroxide. The copolymerization behavior as a function of conversion has been simulated for the both systems based on experimentally determined monomer reactivity ratios (Table 1) [164]. In comparison with the above-mentioned partially protected PHOST systems, this copolymer does not undergo thermal deprotection up to 180 °C. Furthermore, as mentioned earlier, the conversion of the terf-butyl ester to carboxylic acid provides an extremely fast dissolution rate in the exposed regions and a large... 

Cellulose is the most abundant natural biopolymer and is readily available from renewable resources. Esterified cellulose is a highly flexible material as its properties can be varied by controlling the type and amount of the ester substituents during the chemical manufacturing process. Some cellulose esters have been applied as optical films for decades by virtue of their excellent properties such as high transparency and heat resistance. The cellulose ester used is mainly cellulose acetate, while the applications are rather limited to photographic films and protective films. 

Uses Phenolic for heat-curable phenolic/epoxide resin combinations, can coatings, chemically resist, protective coatings Properties Dilutable with MEK, MIBK, ethyl acetate, butyl acetate, methoxypropyl acetate, methoxypropanol dens. = 1.05 g/cm (20 C) dynamic vise. 180-300 mPa S flash pt. = 43 C 63-67% NV Storage 6 mos min. shelf life stored in original containers below 25 C Phenodur PR 260/68B [Solutia]... 

Modification by the incorporation of metals or metalloids, styrene, vinyl acetate, poly(styrene-co-maleic anhydride), urethane linkages, and so on result in poly(ester amide) resins with good chemical properties and excellent thermal resistance. Some can also be used as effective antibacterial and biologically safe corrosion protective coating materials. Urethane-modified ethylenediamine tetraacetic add the fatty amide diol of linseed oil-based poly(ester amide) resin exhibits excellent physicomechanical properties, high thermostability up to 200°C and anticorrosive properties. ... 

Most compounders use a combination of physical and chemical antiozonants and achieve excellent protection in this way. For more severe ozone-resistance problems, there are, of course, a number of specialty elastomers that are saturated and therefore completely ozone-resistant ethylene/propylene rubber, chlorinated and chlorosulfonated polyethylene, ethylene/vinyl acetate, ethylene/acrylic esters, butyl rubber, SEES, plasticized PVC, butyl acrylate copolymers, polyepichlorohydrin and copolymers, polyetherester block copolymer, polyurethane, and silicone. 

Metallic lead is soft, bluish white, highly malleable, and ductile. It is a poor conductor of heat and electricity and resistant to corrosion. A protective film of basic carbonate is formed on the surface of lead exposed to moist air. Lead reacts with water in the presence of air to form lead hydroxide. Inorganic Pb(II) compounds are mainly insoluble or slightly soluble in water. Exceptions are lead chlorate, perchlorate, nitrate, and acetate. Lead chloride is moderately soluble (9.9 g/liter at 20°C). The most important organolead compounds are tetramethyllead and tetraethyllead used as antiknock additives in fuel. Both are colorless liquids at room temperature with boiling points 110 and 200°C, respectively. Photolytically these degrade to RaPb , R2Pb , and Pb. The different chemical forms of lead have different toxicity, so that speciation information is important [1,2]. 

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