The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Arnost Reiser - One of the best experts on this subject based on the ideXlab platform.
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the molecular mechanism of Novolak diazonaphthoquinone resists
European Polymer Journal, 2002Co-Authors: Arnost Reiser, J.p. Huang, T.f. Yeh, S. Jha, H.y. Shih, M.s. Kim, Yu-kai Han, K. YanAbstract:Abstract Novolak–diazonaphthoquinone (DNQ) resists are photosensitive varnishes that are used in the fabrication of more than 80% of today's integrated circuits. They have played a crucial role in an unprecedented technical revolution, yet until quite recently nobody really knew how they work. We have been concerned with this problem for some time and we realize now that the principal functions of Novolak resists, namely the inhibition by DNQ derivatives of the dissolution of Novolak films, and the cessation of inhibition on exposure to radiation, are essentially physical phenomena. Dissolution inhibition is caused by an electric stress imposed on the phenol groups of the resin by the inhibitor. This effect penetrates deep into the material through the formation of hydrogen-bonded phenolic strings. Exposure relieves the stress by uncoupling the strings from the source of induction. The concept of phenolic strings is new and unusual, but it is essential for the understanding of dissolution inhibition. With it, all the many aspects of Novolak resists can be interpreted in a unified manner.
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The molecular mechanism of Novolak–diazonaphthoquinone resists
European Polymer Journal, 2002Co-Authors: Arnost Reiser, J.p. Huang, T.f. Yeh, S. Jha, H.y. Shih, M.s. Kim, Yu-kai Han, K. YanAbstract:Abstract Novolak–diazonaphthoquinone (DNQ) resists are photosensitive varnishes that are used in the fabrication of more than 80% of today's integrated circuits. They have played a crucial role in an unprecedented technical revolution, yet until quite recently nobody really knew how they work. We have been concerned with this problem for some time and we realize now that the principal functions of Novolak resists, namely the inhibition by DNQ derivatives of the dissolution of Novolak films, and the cessation of inhibition on exposure to radiation, are essentially physical phenomena. Dissolution inhibition is caused by an electric stress imposed on the phenol groups of the resin by the inhibitor. This effect penetrates deep into the material through the formation of hydrogen-bonded phenolic strings. Exposure relieves the stress by uncoupling the strings from the source of induction. The concept of phenolic strings is new and unusual, but it is essential for the understanding of dissolution inhibition. With it, all the many aspects of Novolak resists can be interpreted in a unified manner.
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Effect of resin molecular weight on Novolak dissolution
Advances in Resist Technology and Processing XV, 1998Co-Authors: Hsiao-yi Shih, Arnost Reiser, Huifang Zhuang, Paula M. Gallagher-wetmoreAbstract:An interpretation of the effect of resin molecular weight on the dissolution of Novolak is offered. It is based on Eyring's transition state theory and on the percolation model of Novolak dissolution. The rate determining step of Novolak dissolution is the deprotonation of phenol by base at the front edge of the penetration zone. In order for this reaction to occur, an ion pair of base must appear at the interface of the penetration zone with the virgin matrix. To make this possible, all base ions of the corresponding percolation channel have to move forward in synchronism, and this requires the simultaneous thermal activation of all the sites of the channel. At this point the mechanism of energy transport in an ensemble of polymer chains intervenes: thermal (vibrational) energy propagates much faster along the chains then between them. It can be shown that the probability that a particular site will receive an activating quantum is inversely proportional to the length of the chain to which the site belongs.The application of these principles leads to a quantitative description of the activation entropy and the activation energy, and hence of the rate of Novolak dissolution as a function of resin molecular weight.
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Percolation View of Novolak Dissolution. 9. Deuterium Isotope Effect on Dissolution Rate
Macromolecules, 1997Co-Authors: Myoung Soo Kim, Arnost ReiserAbstract:A commercial Novolak resin was partially (OH groups) deuterated, and the dissolution rate of the deuterated material in 0.1 N solutions of KOD, NaOD, and LiOD in D2O was measured. The dissolution of the deuterated systems is considerably slower than that of the corresponding protonated systems. In both cases the dissolution rate depends on the nature of the base cation, and it is in fact a linear function of the reciprocal cross section of the ions. These results are compatible with the view that the rate-determining step in Novolak dissolution is the deprotonation of phenol groups at the interface of the penetration zone with the resin matrix. The dissolution of deuterated Novolak in deuterated developers is strongly affected by the presence of salts of the base cations, in a manner similar to that of the protonated systems investigated in refs 1 and 2.
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Percolation View of Novolak Dissolution. 5. The Dissolution of Exposed Resist Films
Macromolecules, 1996Co-Authors: Hsiao-yi Shih, Arnost ReiserAbstract:Dissolution inhibition produced by diazonaphthoquinones in Novolak and in other phenolic resins is based on the formation of phenolic clusters. The principal result of the exposure of Novolak−diazoquinone resist films to light is the dispersal of these clusters. It occurs through the thermal effect of the Wolff rearrangement that follows the photolysis of diazonaphthoquinone. Indenecarboxylic acid, which is the final product of irradiation, is converted to indenecarboxylate ion in the penetration zone of the dissolving films, where it adds to the concentration of hydrophilic percolation sites. This causes the dissolution rate of exposed resist films to be accelerated above that of pure Novolak.
Chen-chi M. - One of the best experts on this subject based on the ideXlab platform.
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Blocked diisocyanate polyester-toughened Novolak-type phenolic resin : Synthesis, characterization, and properties of composites
Journal of Applied Polymer Science, 1998Co-Authors: Chen-chi M., Han-thing TsengAbstract:A blocked diisocyanate polyester was synthesized to copolymerize with Novolak-type phenolic resin. From the results of IR and NMR spectra, it was found that the blocked diisocyanate polyester reacts with the hydroxyl group of the Novolak-type phenolic resin at high temperature. The deblocking temperature for the Novolak-type phenolic resin is 120°C. The blocking agent, e-caprolactam, is convenient for this system. The copolymer exhibited a single glass transition temperature and a negative deviation of the glass transition temperature. The results showed that the copolymer system is miscible and the molecular motion of the copolymer is increased with the addition of a modifier. The interface between the modified phenolic resin and the glass fiber is improved and the tensile strength of pultruded composite is increased with the modifier content. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1119–1127, 1998
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Pultruded fiber reinforced novolac type phenolic composite—processability, mechanical properties and flame resistance
Composites Part A-applied Science and Manufacturing, 1998Co-Authors: Chen-chi M., Ming-shiu LeeAbstract:Abstract The processability, mechanical properties and flame resistance of glass fiber reinforced pultruded novolac type phenolic resin based composite have been investigated. The suitable viscosity of novolac, between 1200–2700 cps, for pultrusion processes was synthesized. The novolac type phenolic resin shows lower processing temperature, longer pot life, and lower water content than the resole type resin. Hence, the novolac phenolic resin is more stable in the pultrusion process than the resole resin. The resultant composites of novolac type showed good mechanical properties and high flame resistance.
Ming-shiu Lee - One of the best experts on this subject based on the ideXlab platform.
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Pultruded fiber reinforced novolac type phenolic composite—processability, mechanical properties and flame resistance
Composites Part A-applied Science and Manufacturing, 1998Co-Authors: Chen-chi M., Ming-shiu LeeAbstract:Abstract The processability, mechanical properties and flame resistance of glass fiber reinforced pultruded novolac type phenolic resin based composite have been investigated. The suitable viscosity of novolac, between 1200–2700 cps, for pultrusion processes was synthesized. The novolac type phenolic resin shows lower processing temperature, longer pot life, and lower water content than the resole type resin. Hence, the novolac phenolic resin is more stable in the pultrusion process than the resole resin. The resultant composites of novolac type showed good mechanical properties and high flame resistance.
S. Nakamura - One of the best experts on this subject based on the ideXlab platform.
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Preparation and properties of epoxy resins cured with silyl esters of phenol Novolak and cresol Novolak
Journal of Thermal Analysis and Calorimetry, 2002Co-Authors: Y. Nishimoto, K. Ueoka, S. NakamuraAbstract:The curing agents of epoxy resin, trimethylsilyl ethers of phenol Novolak (TMSPN) and cresol Novolak (TMSCN) were prepared by refluxing phenol Novolak and cresol Novolak respectively, with the mixture of hexamethyldisilazane and chlorotrimethylsilane in THF. The curing reaction of epoxy resin with these curing agents and the thermal properties of cured resins were examined. The Tg values of epoxy resins cured with TMSPN were a little higher than those cured with TMSCN. The maximum of Tg is 118°C for TMSPN-cured epoxy resin against 112°C for TMSPN-cured epoxy resin. The water absorption of hydrophobic epoxy resins cured with TMSPN was a little lower than those cured with TMSCN. The clear decrease of water absorption is attributed to the difficulty of the micro-void formation caused by the more tight primary structures of TMSPN. The water absorption at 25°C containing trimethylsilyl groups is about one-tenth of that of epoxy resins cured with conventional curing agents and even one-half of that of the epoxy resins cured with active esters. The low water absorption is attributed to the presence of trimethylsilyl groups, which are more hydrophobic than ester groups, and to the absence of hydroxyl groups of the cured resins.
Makoto Hanabata - One of the best experts on this subject based on the ideXlab platform.
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Effects of phenolic compound addition to fractionated Novolak-based resists to improve resolution capability(2)
Advances in Patterning Materials and Processes XXXIV, 2017Co-Authors: Atsushi Sekiguchi, Makoto Hanabata, Yoko Matsumoto, Yoshihisa Sensu, Satoshi Takei, Hatsuyuki TanakaAbstract:Novolak resists have been widely used in IC production and are used to this day in the production of flat panel displays (FPDs) and MEMS. However, with the advent of high-definition devices, FPDs must meet growing requirements for finer dimensions. These trends have generated requirements for higher sensitivity, higher resolution, and wider process margins for Novolak resists. Using a lithography simulator with the goal of improving the performance of Novolak resists, we examined various approaches to improving resist materials. This report discusses efforts to improve resolution and to broaden process margins using a Novolak resin that exhibits a higher degree of fractionation than in the previous report (maximum fractionated resin) with the addition of low molecular weight phenol resins.
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Enhancing the Novolak resin resist resolution by adding phenol to fractionated resin
Advances in Patterning Materials and Processes XXXIII, 2016Co-Authors: Atsushi Sekiguchi, Yoko Matsumoto, Hatsuyuki Tanaka, Toshiyuki Horiuchi, Yoshihisa Sensu, Satoshi Takei, Makoto HanabataAbstract:Novolak resists have been widely used in IC production and are still used in the production of flat panel displays (FPDs) and MEMS. However, with the advent of high-definition products, FPDs increasingly face requirements for finer dimensions. These trends have generated requirements for higher sensitivity, higher resolution, and wider process margin for Novolak resists. Using a lithography simulator with the goal of improving the performance of Novolak resists, we examined various approaches to improving resist materials. This report discusses efforts to improve resolution and sensitivity using highly fractionated Novolak resins and adding low molecular weight phenol resins.
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Novolak design concept for high performance positive photoresists
Polymer Engineering and Science, 1992Co-Authors: Makoto Hanabata, Akihiro FurutaAbstract:Novolak resins have been optimized for high performance positive photoresists. Low molecular weight Novolak resins are the key components for improving resolution capability, sensitivity, and heat resistance of positive photoreslsts. Various phenolic compounds (monomers) and oligomers of metacresol Novolak resins were evaluated as low molecular weight components. It was found that phenolic compounds that have moderate hydrophobicity and azocoupling capability with diazonaphthoquinone compounds greatly improve positive photoresist performance
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Novolak design for high-resolution positive photoresists (IV): tandem-type Novolak resin for high-performance positive photoresists
Advances in Resist Technology and Processing VIII, 1991Co-Authors: Makoto Hanabata, Akihiro FurutaAbstract:A new type of Novolak resins is proposed for high performance positive photoresists. This Novolak resin has a molecular weight distribution different from the existing materials and is characterized by its low content of middle molecular weight components. We call this Novolak resin 'Tandem type Novolak resin'. The positive photoresists that contain Tandem type Novolak resins exhibit improved performance in resolution, sensitivity, and heat resistance which are usually balanced in trade-off relationships. The characteristics, syntheses, and advantages of Tandem type Novolak resins are described. The mechanism of resist performance improvement will also be discussed.
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A selection principle of phenolic compounds for Novolak resins in high performance positive photoresists
Journal of Vacuum Science & Technology A: Vacuum Surfaces and Films, 1991Co-Authors: Makoto Hanabata, Akihiro FurutaAbstract:The relationship between resist performance and the kinds of phenolic compounds for Novolak resins was investigated from the standpoint of the image formation process. Dissolution rates were measured on photoresists containing Novolak resins made from various phenolic compounds including phenol, cresol, ethylphenol, butylphenol, and their copolymers. It was found that there are suitable combinations of phenolic compounds to exhibit high resist performance. On the basis of the experimental results, we discuss the effect of the kinds of phenolic compounds on the dissolution characteristics and the structure of Novolak resins. Finally, we propose a selection principle of phenolic compounds for Novolak resins useful to design high performance positive photoresists.
