This study presents creep characteristics of three types of polyamide-resin thin films with different silica filler contents used in electronic devices. Silica fillers were mixed into the polyamide resin to reduce thermal stress. Tensile creep tests were performed at 398 K and 423 K using a specimen of the polyamide resin thin films 30 mm in gage length, 5 mm in width, and 15 μm in thickness. Minimum creep-strain rates and rupture lifetimes were significantly influenced by both the filler content of the resin and the testing temperature. Increasing the filler content reduced the minimum creep strain rate resulting in the increase in creep rupture lifetime. Minimum creep-strain rate and rupture lifetime at 398 K and 423 K were approximated as rules of mixture models of the filler content corresponding to temperature.

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We evaluated the thermal fatigue properties of Sn-3.0wt%Ag-0.5wt%Cu (SAC), Sn-3.5wt%Ag-0.5wt%Bi-6.0wt%In (SABI), and Sn-3.5wt%Ag-0.5wt%Bi-6.0wt%In-0.8wt%Cu (SABIC) solder joints with Cu-OSP and Au/Ni plated electrodes. SABI and SABIC, which contain In, showed good properties with the Cu-OSP electrode. With the Au/Ni plated electrode, SABIC showed better properties than the other solders. SABI generated a (Ni, Cu)₃Sn₄ intermetallic layer at the joint interface with the Au/Ni plated electrode. The thickness of the (Ni, Cu)₃Sn₄ intermetallic layer increased rapidly and the In content in the (Ni, Cu, Au)₃Sn₄ intermetallic layer increased over the course of the thermal fatigue test. In contrast, SABIC generated a (Cu, Ni, Au)₆Sn₅ layer and there was no increase of In content in the (Cu, Ni, Au)₆Sn₅ layer.

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A semiconductor chip was evaluated and analyzed using the AC impedance method in this report. The aim of this study is to establish an evaluation method for EM. An appropriate current density was applied to the TEG sample fabricated using a copper damascene method. Concurrently, the AC impedance was measured by use of a frequency response analyzer before and after the EM test. Additionally, the occurrence of electromigration was observed after the test using a digital microscope. We succeeded in observing the change in the form of the Cole-Cole plot of the AC impedance after EM. However, this is considered to be evidence of the change in the contact state of the wire and the copper plate. It is suggested that the change in the contact state derived from the energization could be monitored using an AC impedance method. Thus, this method will be applicable to estimating the contact state when performing an EM evaluation.

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Solder resist materials which do not contain solvent as a component and can be applied to off-contact exposure method were studied for their application to alkaline-developable solder resists of printed circuit boards. We found a photopolymerization initiator system composed of photoradical initiator, amine and thiaxanthone which showed good curability both on the surface and in the interior under aerial condition. We also succeeded in preparation of alkaline-developable photosensitive resin by two-step reactions starting from novolac-type epoxy resin.
Effect of solid and liquid epoxy resin components added for thermal post-curing on properties as solder resist was also examined. As a result, regardless of the epoxy component, the solder resists having good adherence, high solder heat resistance of 260°C for 30 s and resolution of 100 μm or higher were successfully obtained. These results demonstrate that a solder resist which is developable with alkaline solution and applicable to printed circuit boards for general uses can be produced from liquid photosensitive resins without solvent component.

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