Browsing by Author "Jwo, SL"

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Effects of morphology and surface characteristics of poly(imide siloxane)s and deep UV/O-3 surface treatment on the interfacial adhesion of poly(imide siloxane)/alloy-42 leadframe joints
(1999-07-01)
Jwo, SL
;
Whang, WT
;
Hsieh, TE
;
Pan, FM
;
Liaw, WC
The effect of surface characteristics and morphology of poly(imide siloxane) (PIS) on the true interfacial adhesion between PIS films and alloy-42 substrates was studied. The effect of the viscosity of PIS films and the surface treatment of deep UV/O-3 (d-UV/O-3) on alloy-42 plates on the peel strength of PIS films/alloy-42 joints has also investigated. 3,3',4,4'-benzophenone tetracarboxylic dianhydride/2,2'-bis[4-(3-aminophenoxy)phenyl]sulfone (BTDA/m-BAPS) based PIS films with alpha,omega-bis(3-aminopropyl)polydimethyl siloxane (APPS) molecular weight M-n = 996 g/mole (PIS9Siy) show two phases in all compositions and the linear dependence of the critical surface tension on the surface concentration of the silicon, [Si-surf], on the PIS films. The PIS films with the APPS M-n = 507 g/mole (PIS5Siy) or M-n = 715 g/mole (PIS7Siy) exhibit a morphology change from a homogeneous phase to an inhomogeneous phase starting at the mole ratio (y) of APPS/PIS = 2.7% and 1.1%, respectively. The curves of critical surface tension dependence on the [Si-surf] discontinue or deflect at these two compositions, respectively. The treatment of d-UV/O-3 on alloy-42 plates improves the wetting on the alloy surface and promotes the peel strength between the PIS films and alloy-42 plates by a magnitude of greater than or equal to 20%. These results show that the flowability of the same PIS films bonding at different temperatures significantly affects the bonding strength of the joints, but the flowability of different PIS films bonding at the same temperature, e.g. 400 degrees C, is not the key factor governing the bonding strength of the joints. The true interfacial adhesion of the PIS5Si0.6/alloy-42 joint is 80% higher than that of the unmodified BTDA/m-BAPS based polyimide film/alloy-42 joint. However, zero true interfacial adhesion is obtained between the PIS9Siy films and alloy-42 plates. The wetting kinetics experiment shows that the higher the siloxane content in the PIS, the higher the activation energy for the adhesive bonding process. Moreover, the phase sepration significantly increases the activation energy. The scanning electron micrographs of the peeled-off PIS film surfaces from the PIS/alloy-42 joints reveal the rougher surface morphology from the sample with the higher interfacial adhesion.
Effects of the solubility parameter of polyimides and the segment length of siloxane block on the morphology and properties of poly(imide siloxane)
(1999-12-13)
Jwo, SL
;
Whang, WT
;
Liaw, WC
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The dependence of morphology of the poly(imide siloxane)s (PISs) on the solubility parameter of unmodified polyimides and the molecular weight and content of alpha,omega-bis(3-aminopropyl) polydimethylsiloxane (APPS) has been studied. The effect of the morphology on the mechanical properties is also under investigation. The domain formation in the PISs with the APPS molecular weight M-n = 507 g/mol is not found until the mol ratio of APPS/PIS greater than or equal to 0.5% in the pyromellitic dianhydride/p-phenylene diamine (PMDA/p-PDA)-based PISs, and at a mol ratio greater than or equal to 2.7% in the 3,3',4,4'-benzophenone tetracarboxylic dianhydride/2,2'-bis[4-(3-aminophenoxy)phenyl] sulfone (BTDA/m-BAPS)-based PISs. As the APPS M-n = 715 g/mol, the critical APPS concentrations of the domain formation in both types of PISs are equal to 0.1 and 1.1%, respectively. The critical concentration is equal to 0.6% in the BTDA/m-BAPS-based PIS film with the APPS M-n = 996 g/mol. The isolated siloxane-rich phase in the BTDA/m-BAPS-based PISs becomes a continuous phase as the ,ol ratio of APPS/PIS greater than or equal to 7.7, 10.0, and 16.6% as the APPS M-n = 996, 715, and 507 g/mol, respectively. Dynamic Mechanical Analysis (DMA) shows two T(g)s in the PIS films having phase separation: one at -118 similar to -115 degrees C, being the siloxane-rich phase, the other at 181-244 degrees C, being the aromatic imide-rich phase. The SEM micrographs show a significant deformation on the fractured surfaces of the BTDA/m-BAPS-based PIS films with a continuous siloxane-rich phase. This phenomenon of plastic deformation is also observed in the tensile tests at -118 degrees C and at room temperature. The highest elongation in the PIS films is found at the critical siloxane content of the continuous siloxane-rich phase formation. (C) 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2832-2847, 1999.