Poly terpolymer resist

Polycarbonate is blended with a number of polymers including PET, PBT, acrylonitrile-butadiene-styrene terpolymer (ABS) rubber, and styrene-maleic anhydride (SMA) copolymer. The blends have lower costs compared to polycarbonate and, in addition, show some property improvement. PET and PBT impart better chemical resistance and processability, ABS imparts improved processability, and SMA imparts better retention of properties on aging at high temperature. Poly(phenylene oxide) blended with high-impact polystyrene (HIPS) (polybutadiene-gra/f-polystyrene) has improved toughness and processability. The impact strength of polyamides is improved by blending with an ethylene copolymer or ABS rubber. 

Poly(butyral-co-vinyl acetate-co-vinyl alcohol) - A terpolymer with greater water resistance than polyvinyl acetate, but good adhesion to tissue when applied in ethanol solution. 

Conventional ABS polymers are blends of poly (styrene-coacrylonitrile) with either poly (butadiene-coacrylonitrile) or a graft of poly-(styrene-coacrylonitrile) onto a rubbery spine. To confer flame-resistance on either ABS system using DBPF as a fourth monomer, the major component should be a styrene-acrylonitrile-DBPF terpolymer since the resinous component is the major one. The composition of such a terpolymer is restricted by two considerations (1) it should contain sufficient acrylonitrile to impart the resistance to solvent attack which is characteristic of ABS polymers, and (2) the amount of DBPF should be sufficient to give a useful level of flame resistance. 

Glasgow [1] prepared a blend consisting of the reaction product of bisphenol A and diphenyl carbonate with poly(caprolactone-b-dimethylsiloxane-b-poly-caprolactone) terpolymer that showed superior resistance to scratching and haze while having excellent transmittance properties. Food and medical articles derived from this blend were readily sterilized by steam at atmosphere pressure as taught by Chatteijee [2]. 

In ASA terpolymer acrylic acid brings more flexibility and the material has very good mechanical properties and weather resistance. For these reasons ASA is extensively used in automotive industry and in the fabrication of various appliances. Even more frequently than acrylic acid itself, various acrylates are used in copolymers. Among these can be mentioned the copolymers of acrylic acid esters with methacrylic acid esters such as poly(methyl methacrylate-co-methyl acrylate), poly(methyl methacrylate-co-ethyl acrylate), poly(methyl methacrylate-co-butyl acrylate), poly(ethyl methacrylate-co-ethyl acrylate), poly(acrylonitrile-co-methyl acrylate), poly(alkyl acrylate-co-methyl methacrylates), and poly(alkyl acrylate-co-hydroxyethyl methacrylates) where alkyl can be methyl, ethyl, butyl, etc. Some literature information regarding thermal decomposition of copolymers including acrylic acid and acrylic acid esters is given in Table 6.7.8 [6],... 

A copolymer approach can provide more flexibility to the resist design because all the necessary functions do not have to reside on one component. Today s advanced positive deep UV resists are exclusively based on this concept with 4-hydroxystyrene as one component. However, early copolymer systems and some of the 193-nm resists consisted of lipophilic components only. Incorporation of 4-acetoxystyrene to poly(4- er -butoxycarbonyloxystyrene sulfone) has already been mentioned. This section deals with copolymer resists composed of lipophilic comonomers first and then the currently dominant hydroxystyrene copolymers. Co- and terpolymers for ArF excimer laser lithography will be described in a separate section. 

O-methylated PHOST [179]. This terpolymer was originally developed as a chemically amplified laser resist for circuit board application [180] and then as a single layer 193 nm positive resist [181], which will be described in more detail later. Another interesting three-component approach is the use of a N-acetal polymer as a dissolution inhibitor of poly(3-methyl-4-hydroxystyrene) [182]. A deep UV resist consisting of poly(3-methyl-4-hydroxystyrene-co-4-hydroxystyrene), poly(N,0-acetal), bis(arylsulfonyl)diazomethane, and a photobase was reported from Hoechst (currently Clariant). The function of the photobase is described later. A copolymer of 4-hydroxystyrene with styrene was also employed as a matrix resin. 

A thermogravimetric analysis (TGA) profile of a typical alicyclic copolymer resist resin, poly(CBN-co-NBCA), is shown in Fig. 7.15. All of the alicyclic resist co-and terpolymers show similar TGA profiles. The deprotection temperature and decomposition temperature for the polymers are roughly 250°C and 400°C, respectively. At the deprotection temperature, roughly 25% weight loss associated with the deprotection event and corresponding to the loss of isobutylene and carbon... 

Surface oxidation reactions have been carried out on a number of polymers, particularly polyethylene. Surface oxidation techniques include the use of corona discharge, ozone, hydrogen peroxide, nitrous acid, alkaline hypochloride, UV irradiation, oxidizing flame, and chromic acid The reactions lead initially to the formation of hydroperoxides, which catalyze the formation of aldehydes and ketones and finally, acids and esters. Surface oxidation treatment has been used to increase the printabdity of polyethylene and poly(ethylene terephthalate) and to improve the adhesion of polyethylene and polypropylene to polar polymers and that of polytetrafluoroethylene to pressure-sensitive tapes. Surface-oxidized polyethylene, when coated with a thin film of vinylidene chloride, acrylonitrile, and acryhc acid terpolymers becomes impermeable to oxygen and more resistant to grease, oil, abrasion, and high temperatures. The greasy feel of polyethylene has also been removed by surface oxidation. 

Alkali and acid treatments have also been used to modify surface properties of polymers sulfonated polyethylene films treated first with ethylenediamine and then with a terpolymer of vinyhdene chloride, acrylonitrile, and acrylic acid exhibited better clarity and scuff resistance and reduced permeabihty. Permanently amber-colored polyethylene containers suitable for storing light-sensitive compoimds have been produced by treating fluorosulfonated polyethylene with alkali. Poly(ethylene terephthalate) dipped into trichloroacetic/chromic acid mixture has improved adhesion to polyethylene and nylons. Antifogging lenses have been prepared by exposing polystyrene films to sulfonating conditions. Acid and alkali surface treatments have also been used to produce desired properties in polymethylmethacrylates, polyacrylonitrile, styrene-butadiene resins, polyisobutylene, and natural rubber. Surface halogenation of the diene polymers natural rubber and polyisobutylene resulted in increased adhesion to polar surfaces. 

Poly(vinyl acetate) dispersions form lightfast, dry, hard, brittle films. Plasticizers therefore have to be used (external plasticization), which are, however, volatile and lead to embrittlement of the films after a relatively short time. Internally plasticized dispersions of copolymers of vinyl acetate with vinyl laurate, butyl maleate, Versatic Acid esters, or ethylene form permanently flexible, nonaging films that are not, however, always sufficiently resistant to hydrolysis. Terpolymer (vinyl acetate-ethylene-vinyl chloride) dispersions form films that are more resistant to hydrolysis than homopolymer and copolymer dispersions. The films also have a higher mechanical strength and lower flammability. The glass transition temperature of the terpolymer can be varied within wide limits and properties can be matched to requirements by using a suitable choice of comonomers. The same is true of vinyl propionate copolymer dispersions. 

Even when PPS has superior chemical resistance and heat stability, its brittleness may be a drawback for certain applications. The physical properties of PPS can be improved by the addition of small amounts of terpolymers of ethylene, methylacrylate, and glycidyl methacrylate, also in a grafted variant with poly(methyl methacrylate) [59]. The manufacture of the composition occurs by melt mixing under a high shear rate. 

One-component positive resists are essentially copolymers or terpolymers derived from PMMA. Copolymer strnctnres are chosen in order to increase the low value of the absorption coefficient of PMMA at 215 nm. Comonomers are selected either to absorb in the 230-280 nm range or becanse they contain a photosensitive chromophoric group. Poly(methyl methacrylate-co-3-oximino-2-butanone methacrylate-co-methacrylonitrile), p(PMMA-OM-MAN) (Figure 6.11), sensitised with t-butyl benzoic acid requires an exposnre dose of less than 30 mj/cm [18]. 

The sensitivity of this terpolymer is 170 times that of PMMA and is capable of sub-micron resolntion. Poly(aromatic snlfones) may also be nsed as positive resists [19]. Their quantum efficiency is low, however. Aromatic moieties ensnre a useful plasma etch resistance. 

A terpolymer of vinyl acetate-maleic acid-vinyl chloride looks to be potentially useful for reducing the surface resistivity of chlorinated poly(vinyl chloride).The terpolymer may also be useful in a variety of antistatic coatings. 

This post-cme step is required to reach the best vulcanizate properties (tensile strength, modulus at 50 or 100% elongation, compression set resistance, elongation at break) [28,40,108,111]. Tables [35] shows the improvement of compression set resistance with post curing, for fom samples containing poly(VDF-ter-HFP-ter-TFE) terpolymer crosslinked with a peroxide [2,5-bis(t-butylperoxy)-2,5-dimethylhexyne] in the presence of triaUyhso-cyanurate [35,108,112,113[. Table 2 [35[ presents the improvement of some mechanical properties of bisphenol and peroxide cured systems with post cure. 

TableS Compression set resistance measured at 204 °C for 70 h, of a peroxide cured-poly(VDF-ter-HFP-fer-TFE)terpolymer, after press cure in air at 177 °C for 15 min, and after post cure in air or under nitrogen at 232 °C for 24 h [35]...

Compression set resistance at 200 °C was compared between a TecnoflonT poly(VDF-ter-HFP-ter-1 -hydropentafluoropropene) terpolymer vulcanized with HMDA-C, and TecnoflonT vulcanized with piperazine carbamate [131]. The results are included in Fig. 12 [131]. Curves 3 and 4 are both poly(VDF-co-HFP) copolymer vulcanizates with piperazine carbamate in the presence of trimethylenediamine carbamate and MgO for curve 3, and bisphenol in the presence of MgO for curve 4. The compression set resistance is better for curve 4, than curve 2, which is better than curve 3, and finally the worst compression set resistance is obtained for Tecnoflon T vulcanized with HMDA-C. 

The compression set percentage of a cured poly(VDF-ter-HFP-ter-TFE) terpolymer, press cured and post cured under nitrogen or air (Table 3) was studied [35]. The authors noted first that post cure drastically improves the compression set resistance of the press-cure sample, and second a nitrogen atmosphere leads to better post cure results than air atmosphere. It can be concluded that post cure improves compression set resistance all the more if it is carried out under nitrogen in order to avoid oxidative scissions. Consequently, the scissions in or at the crosslink are due to oxygen [35]. 

Flisi [ 131 ] also study the compression set resistance at 200 °C versus ageing time for different diamine and bisphenol Tecnoflon T [poly(VDF-ter-HFP-ter-TFE) terpolymer] vulcanizates (Fig. 12). 

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