Recently, dismantlement of adhesively bonded joints has been required to recycle the materials of adherends.So that, we developed a new kind of adhesive: "dismantlableadhesive".The joints bonded with the adhesive were peeled off easily by adding heat due to the expansion of thermally expansive microcapsules included in it.Thermal expansion of the microcapsules and the dismantlable adhesive was measured keeping applied hydrostatic pressure usinga Pressure-Volume-Temperature apparatus.The microcapsule began to expand drastically at around 60℃ under atmospheric pressure and 1MPa.However, the expansion started at around 80-90℃ under 2MPa and 3MPa.They swelled over 60 times in volume at 100℃ under atmospheric pressure but not more than 10 times at 1MPa.The dismantlable adhesive was also expanded similarly to the experiment using only the microcapsules.In addition, volume modulus of the dismantlable adhesive was measured using the PVT apparatus.

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Theepoxyresin-basedpastebondingadhesivescauseseriousproblemsinfabricatingstackedintegratedcircuits(ICs).Inanattempttosolvesuchproblemsandsimplifytheprocedure,dualcuringwasstudiedonthemixedformulationsofUV-curablepressuresensitiveadhesives(PSAs)andthermallycurableepoxyr､esins・AnUV-curablePSAwascomposedofanacryliccopolymeranddipentaeritbrytolhexaacrylate(DPHA).FormulationstudyonUV-curableandepoxyresinmixturesfoundtwomajorfactorsforbettercompatibilityandsuitablepropertiesasPSA.Onefactorwastheincorporationofglycidylmetbacrylate(GMA)intothecopolymer.andtheotherwastheepoxycomponentwasamixtureofliquidandsolidbispbenolAglycidylethersandaphenol-novolaktypeepoxyresin.TheUVcuringofsuchaformulationconvei､tedtheadhesivelayei､tothatofexcellentdicingperformancesandeasypickingupofsemiconductordicewithitself.Furtherthermalcuringoftheadhesivelayerthusobtainedconverteditbondinglayerwithsuchanincreasedelasticmodulusas1.0×10**Paevenathighertemperaturethan150C.Bycomparingwithacommerciallyavailabledicingtapeandepoxypaste-bondingagent,itwasascertainedthatthenewlydevelopedformulationhasmorethanequaldicingandbondingperformances.

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The interfacial adhesion energies and subsequent adhesion strengths of adhesive/substrate pairs are the primary focus of this research paper.The interfacial energies of adhesion between adhesives and substrates were calculated using DFT (Density Functional Theory) - one of the sophisticated molecular orbital calculation methods.The calculation program was modified for precise calculations of energies in even larger systems consisting of more than 300atoms.Poly (butylacrylate-co-acrylicacid), -molar ratios 6:0, 5:1, and 4:2-were selected as model adhesives.Gold crystal surface and poly (dimethylsiloxane) surfaces were chosen as model substrates.In addition, other experiments were carried out to measure the adhesion strength of these adhesive/substrate pairs.As a result, good correlations were observed between the calculated energies and the measured strengths.Also, the energy decomposition analysis was done to determine the reason why acrylic acid content makes the interaction with gold's sureface stronger.The results indicate that the polarization and electrostatic interactions of acrylic acid are much greater than those of butyl acrylate with gold's surface.

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