Epoxy resins are widely utilized as molding compounds for electronic devices. The progress of surface mount technology in this industrial field would require the development of higher performance epoxy resins. Here, the synthesis and characterization of the mesogenic epoxy resins and the epoxy/silica hybrid materials are overviewed with emphasis placed on the network chain motion-property relationship. The introduction of mesogenic groups into epoxy networks is effective for improving the toughness and heat resistance, and the hybrization with silica network could improve the mechanical and adhesive bonding properties of cured epoxy resins in the high temperature region.

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Lithography is an important technique for the electronic industries. In the manufacture of a semiconductor and a liquid crystal display (LCD), photoresist is used as a key photo sensitive material. An example is a phenolic as a base resin that controls photoresist characters and plays an active part in the electronic industries. This review describes the results of investigation on the published reports and patents which are concerned with the phenolic photoresists. Kettle materials for a reaction vessel are also introduced for obtaining a specific phenolic resin which is controlled to an extremely low metal content of a ppb level, and manufacturing methods for obtaining a phenolic resin with low-dispersed molecular weight.

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Reliability of semiconductor packages significantly depend on the property of various materials used in the packages, since the packages are composed of a lot of components. Based on the stress analysis, the threshold values of elastic moduli and coefficients of thermal expansion of both a die bonding film and a liquid encapsulant were determined to achieve good connection reliability.
New polymer alloys, based on a low modulus polymer and an epoxy resin, were developed to meet the target values of modulus and CTE.
CSP fabricated with the newly developed materials showed excellent connection reliability and high temperature reflow resistance in lead free requirements.

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Because of the current tendency of high density packaging, over mold packages such as PBGA and FBGA have been increasing. Their asymmetric structure causes warpage of packages, which has brought trouble in mounting process and so on. Recently, MAP type encapsulation has been developed for the small size packages of BGA/CSP, and the substrate has been getting thinner with a larger molded area. Thus molding compounds with less warpage are now strongly required. Decreasing the mold shrinkage of a compound is reported to be effective in decreasing the warpage of packages. A lower mold shrinkage can be achieved by means of getting its Tg higher and its CTE lower. But these methods can not bring a better result by its higher viscosity causing worse moldability. This report describes the development of a new molding compound with low warpage and low viscosity.

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As a series of studies on a new type of phenolic resin by the ring opening reaction of benzoxazines, two kinds of phenol-novolac based benzoxazines having different molecular weights were prepared from the corresponding phenol-novolacs, formaline, and aniline. Curing reaction of the above benzoxazines with bisoxazoline and the properties of the cured resins were investigated. With triphenylphosphite as a catalyst, the ring opening reaction of benzoxazine occurred at 170°C at first to generate a phenolic hydoroxyl group, and then the reaction of which with oxazoline ring followed at 200°C. The difference in the curing reactivity by the molecular weight of benzoxazines was as follows : the lower the molecular weight, the faster the curing reaction due to molecular mobility. The both cured resins showed better heat-and water-resistance and fracture toughness, compared with the conventional cured resins from phenol-novolacs and bisoxazoline. As for the properties of the cured resin from different molecular weights of benzoxazines, the resin having a lower molecular weight showed better fracture toughness, while the resin having a higher molecular weight showed better heat-and water-resistance, and electrical insulation.

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The purpose of this study is to reduce the cure time and to lower the cure temperature of benzoxazine compounds. We investigated the curing behavior of bisphenol-A type novolac based benzoxazine with bisoxazoline (BisAN-a/1, 3-PBO) and the properties of the cured resin. As a result, the molten resin mixture from BisAN-a/1, 3-PBO showed good thermal stability and flowability below 120°C, as well as that from conventional bisphenol-A based benzoxazine and bisoxazoline (B-a/1, 3-PBO). However, above 160°C the curing reaction of BisAN-a/1, 3-PBO proceeded more rapidly than that of B-a/1, 3-PBO. It was found that the cure time of the molten resin mixture from BisAN-a/1, 3-PBO could be reduced and also the cure temperature could be lowered, compared with those from B-a/1, 3-PBO. The cured resin from BisAN-a/1, 3PBO had superior heat resistance and water resistance to that from B-a/1, 3-PBO because of higher crosslink density.

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