Low-modulus die-bonding films are useful for stacked multi-chip packages which are suitable for compact electronic devices. In particular, to cope with the widespread application of very thin semiconductor wafers and Pb-free solders, the films are expected to have both low viscosity in the attaching process and high bonding reliability in the high-temperature reflow process. We studied the phase structure and the properties of a new reaction-induced polymer alloy consisting of a low-modulus acrylic polymer and a highly heat-resistant epoxy resin. As a result, this alloy film was shown to have both high resin flow and good reflow-crack resistance.

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Decoupling capacitor circuits designed for use in industry must have substantially low impedance over a wide frequency range. It has become much more complicated to realize this design objective with the conventional implementation, which uses a combination of discrete capacitors. We have developed a new capacitive device which possesses an internal transmission line structure to address the needs for low-impedance decoupling circuits. The device was applied to the power circuits of notebook PC CPUs and embedded systems with FPGAs for evaluation. In the notebook PC CPU application, this capacitive device was able to substitute for 39 conventional capacitors, thus simplifying the power circuit design, with the added benefit of reducing the board space needed for components. In the FPGA application, the effects of this decoupling device were verified through simulation and actual board measurements. Results confirm that this device is an attractive solution for reducing EMI effects.

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The transient and residual warp deformation of a viscoelastic two-layer-laminated body caused by thermal load was examined experimentally and by finite element and thermo-viscoelastic analyses. The finite element analysis was made in consideration of temperature dependency, and the thermo-viscoelastic analysis was done based on the linear viscoelasticity theory referring to time and temperature dependency. The results clarified that warp deformation behavior is influenced by the ratio of the thickness of epoxy resin and steel, that time and temperature dependency should be considered in the analysis when the composition material contains a polymer, and that thermo-viscoelastic analysis can predict warp deformation behavior with precision in practical use.

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This study examined the effects of multi-ply adhesive and an insulating layer on the residual stress generated in the copper foil portions of a copper clad laminate composed of copper foil/FRP/copper foil. First, copper clad laminates were formed by the hot press method using various multi-ply adhesives as well as various insulating layers. Then, residual stress in the copper foil portions of these samples was measured by the strain gauge method of the layer-removing. The thermal and mechanical properties of the multi-ply adhesive and the insulating layer were measured, and the residual stress of the copper foil portion was analyzed together with these various proper-ties. The following results were identified:
(1) The residual stress generated in the copper foil portion depends more on the coefficient of linear expansion of the mirror plate, multi-ply adhesive, and insulating layer than on that of the copper foil. And, it grows hereafter in order of (I) < (II) < (III) .
(I) α_P=α_A=α_F
(II) α_F<α_P<α_A or α_A<α_P<α_F
(III) α_P<α_F<_A or α_P<α_A<α_F, α_F<α_A<α_P or α_A<α_F<_P
Where, α_P: coefficient of linear expansion of mirror plate, α_A: coefficient of linear expansion of adhesive, α_F: . coefficient of linear expansion of insulating layer.
(2) The residual stress generated in the copper foil portion can be reduced by controlling the coefficient of linear expansion of the multi-ply adhesive.

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In this study, we focused on high frequency currents on LSI. We estimated the high-frequency current distribution on a packaged LSI using the Green's Function method, in which the distribution of current is estimated by a two-dimensional magnetic field as an inverse problem. We used a packaged IC mounted on the PCB and estimated the current distribution on the packaged IC. As a result, we could observe the high-frequency current distribution on the packaged IC and the in- and outflow currents of the packaged IC as emission sources.

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In recent years, as electronic devices have become smaller and multi-functionalized, printed wiring boards (PWBs) have required correspondingly higher density and more integration. Generally, organic materials are used as the insulating material on PWBs. The formation of a conductive layer for wiring on these insulators is a key technology. In particular, a conductive layer with excellent adhesion strength is needed for manufacturing fine-pitch PWBs. We studied the formation of a conductive layer on PET film without the roughening of the resin surface associated with conventional oxidizing agents. A thin layer of hydrophilic polymer was formed on the surface of the PET film, followed by electroless copper plating. The sample obtained by subsequent electroplating had sufficient adhesion strength of 0.8 kN/m.

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