摘要:

AbstractIn 1902, Wolff proposed a mechanism to explain the formation of carboxylic acids from diazo‐oxides; Süs in 1944 invoked this same mechanism for the formation of indene carboxylic acid from diazo‐oxides. Since these materials are currently used in the well known class of AZ photoresists, the Süs mechanism has been referred to many times to explain the positive working nature of the photoresists. In spite of the widespread use and industrial importance of the AZ resists, the validity of the Süs mechanism had not been unequivocally demonstrated to any degree of satisfaction. For these reasons, photochemical studies were initiated to establish the following: (1) Obtain direct spectroscopic evidence for ketene intermediates in the Wolff rearrangement of diazooxides. (2) Determine the reactivity of the ketene towards water and hydroxyl containing organic compounds. (3) Determine the reactivity of the ketene in the AZ resists. Fundamental photochemical decomposition mechanisms have been established for the AZ‐type photoresists; these and recent theoretical results on the Wolff rearrangement are used to convey the technological implications of the

ISSN:0032-3888    

DOI:10.1002/pen.760201602

出版商:Society of Plastics Engineers, Inc.    

年代:1980

数据来源: WILEY

摘要:

AbstractIodinated polystyrene (IPS) is obtained by direct iodination of polystyrene and its lithographic characteristics are investigated. The sensitivity of the polymer to electron beams is increased as the result of iodination by a factor of about 10 and reaches 1 μC/cm2. Coated IPS films are very stable and no changes in exposure characteristics are observed even after pre‐baking at 220°C for 10 min. It is found that crosslinking does not proceed in a vacuum after electron beam exposure. The milling rate of IPS under Ar+bombardment is measured to be 0.25 nm/s. This is lower than that of poly(glycidyl methacrylate‐co‐ethyl acrylate) (0.67 nm/s) and that of permalloy (0.42 nm/s), both obtained under the same conditions. The mechanism of sensitization by iodination is di

ISSN:0032-3888    

DOI:10.1002/pen.760201603

出版商:Society of Plastics Engineers, Inc.    

年代:1980

数据来源: WILEY

摘要:

AbstractPolystyrenes with narrow molecular weight distributions have been chlorinated with only slight broadening of molecular weight distributions to yield materials that are five to six times more sensitive to electron‐beam irradiation. The chlorinated polystyrenes are useful negative resists for electron‐beam lithography. At molecular weights of 3‐4 × 105g/mole, their threshold sensitivities to 20 keV electrons are 1‐2μC/cm2. Their lithographic contrasts are ≥ 1.5; in fact,>2.0 for the narrowest molecular weight distributions. They compare favorably in these regards to polystyrenes of similar molecular weight characteristics. Lithographic relief images that are 80% of the original thickness of the polymer film can be formed at three to four times the threshold dose.The degree of chlorination ranged from 0.65‐0.76 Cl/monomer unit. The infrared spectra of the chlorinated materials resemble the spectrum for poly(4‐chlorostyrene). Elemental analysis indicated, however that some addition of chlorine had occurred. More extensive chlorination or chlorination of the higher molecular weight starting materials broadened the molecular weight distributions.The chlorinated material, a kind of poly(4‐chlorostyrene‐costyrene), is less sensitive than poly(4‐chlorostyrenc) prepared by addition polymerization by al

ISSN:0032-3888    

DOI:10.1002/pen.760201604

出版商:Society of Plastics Engineers, Inc.    

年代:1980

数据来源: WILEY

摘要:

AbstractFifteen negative and four positive resists were tested to determine their proton‐beam sensitivity and contrast. The ratio of the required 20‐keV electron dose (QE) to the required 100‐keV proton dose (QP) ranged from a low value of 7.8 to a high value of 270. In general, the most sensitive resists had the lowest values ofQE/QP. This result is explained as being due to incomplete coverage by reactive species at low proton doses because the incident protons are spaced too far apart. The product ofQPand the weight‐average molecular weight (Mw) was almost constant for a series of narrow dispersivity polystyrenes over theMwrange of 20,000 to 2,600,000. This product was used as a figure of merit for comparing negative

ISSN:0032-3888    

DOI:10.1002/pen.760201605

出版商:Society of Plastics Engineers, Inc.    

年代:1980

数据来源: WILEY

摘要:

AbstractA lithographic process is described which increases the sensitivity of polymers to electron beam irradiation. The free radicals and peroxides produced in a film of polymer by irradiation are used to initiate the grafting of a monomer to form a graft copolymer, the solubility of which may be higher or lower than that of the initial polymer. Acrylic acid has been grafted into poly(methyl methacrylate) films to produce a copolymer which is insoluble in the solvents of PMMA. The sensitivity of this negative system depends on the conditions of grafting and on the conditions of development. A sensitivity of 2.8 10−8C.cm−2at 20 keV has been obtai

ISSN:0032-3888    

DOI:10.1002/pen.760201606

出版商:Society of Plastics Engineers, Inc.    

年代:1980

数据来源: WILEY

摘要:

AbstractThis paper compares the response of resists consisting of novolak resin and diazoquinone sensitizers (inhibitors) to optical and electron‐beam radiation. In both cases, irradiation destroys the sensitizer leading to an increased rate of solubility in alkaline developer. For optical exposure in the near‐uv region, the light is absorbed only by the chromophore sites and a unique quantum efficiency of 0.30 ± 0.03 can be measured for a range of wavelengths and sensitizers (10.5 ± 1.0 eV/bleached site). In the case of electron‐beam exposure, the initial rate of bleaching in pure sensitizer implies that 7.6 ± 0.6 sites are destroyed per 100 eV absorbed (13 ± 1 eV/molecule). In mixtures of sensitizer and resin (i.e., resists), this inherent sensitivity, orG‐value, based on the calculated absorption by the sensitizer only, increases by almost a factor of 2 as the proportion of resin is increased. While the electron and optical exposure both destroy the sensitizer center, absorption spectra and solubility properties show that the end products of the chemical reactions are not the same in the two cases. In addition, high doses of electrons produce cross‐linking and insolubilization

ISSN:0032-3888    

DOI:10.1002/pen.760201607

出版商:Society of Plastics Engineers, Inc.    

年代:1980

数据来源: WILEY

摘要:

AbstractChemical composition effects upon polymer electron energy absorption and radiation chemistry have been identified to develop resist design criteria. By use of Bethe's theory for electron scattering in solids, chemical incorporation of higher atomic‐numbered substituents is predicted to decrease energy absorption and increase scattering. Incorporation of chlorine or fluorine into vinyl polymers at the possible substituent sites is empirically found to have a large effect upon radiationG(scission) andG(crosslink) values.G(scission) values determined for several copolymers over a large range of compositions are found to vary linearly with composition. In contrast,G(crosslink) values are found to be generally less than those predicted from a linear extrapolation between the homopolymer values. Electron beam resist behavior is found to correlate well with theGs/Gxrati

ISSN:0032-3888    

DOI:10.1002/pen.760201608

出版商:Society of Plastics Engineers, Inc.    

年代:1980

数据来源: WILEY

摘要:

AbstractElectron resist properties of three vinylaromatic polymers, polystyrene, polyvinylcarbazole and poly(3‐bromo‐N‐vinylcarbazole) have been examined. Polystyrene and polyvinylcarbazole are high contrast resists of high dry etch resistance, but for adequate sensitivity (D g0.5⩽ ca. 10 μC/cm2at 25 kV) high molecular weights are needed (Mw⩾ 106). Poly(3‐brotno‐N‐vinylearbazole) has a much higher sensitivity (D g0.5= ca. 2 μC/cm2) than the unsubstituted polymer. The sensitivity of polystyrene and polyvinylcarbazole is increased appreciably by addition of organic bisazides as crosslinking agents, e.g. a sensitivity increase of almost an order of magnitude was found upon addition of 3% 4, 4′‐diazidostilbene to polystyrene, high

ISSN:0032-3888    

DOI:10.1002/pen.760201609

出版商:Society of Plastics Engineers, Inc.    

年代:1980

数据来源: WILEY

摘要:

AbstractRelative rates of polymer removal in an oxygen plasma have been measured for 40 polymer samples. The rates of removal are correlated, with structural factors which enhance or retard removal. Strong backbone bonds, aromatic and polar functional groups, and metallic atoms decrease the removal rates. Weak bonds not attached to the‐ polymer backbone have little affect while weak bonds attached directly to the chain or in the chain greatly accelerate removal. Chlorine present in the polymer catalyzes removal. This can be mimicked by mixtures of CF4, and O2for which much enhanced removal rates are observe

ISSN:0032-3888    

DOI:10.1002/pen.760201610

出版商:Society of Plastics Engineers, Inc.    

年代:1980

数据来源: WILEY

摘要:

AbstractOver the past several years the semiconductor industry has placed major efforts into replacing wet processes with dry processes in fabricating electronic devices. Plasma photoresist stripping, plasma cleaning, and other dry etching techniques have replaced wet methods in many product lines. One area that has received little mention but which is vital toward achieving a totally dry manufacturing process is the dry development of photoresist. One production applicable plasma developable photoresist (PDF) process, using a proprietary resist formulation, is reported. Plasma process characterization, such as end point detection, development latitude, and mechanism are discussed. Included also are development temperature, batch film uniformity, and resolution currently obtainable with the PDF process.

ISSN:0032-3888    

DOI:10.1002/pen.760201611

出版商:Society of Plastics Engineers, Inc.    

年代:1980

数据来源: WILEY