Abstract: A semiconductor device is fabricated by forming first metal balls on electrode pads of a semiconductor chip. The first metal balls each can have a sharp tipped anchor. All of the anchors simultaneously flattened slightly only to the extent of equalizing the height thereof. The first metal balls are bonded to electrodes formed on a substrate with wirings by embedding the anchors into the electrodes. Alternatively, second metal balls can be formed on the electrodes which are then flattened to equalize the height thereof. The first metal balls, either with or without the anchors, are bonded to the second metal balls. The first and second metal balls are preferably heated during the bonding step to soften the second metal balls.

Abstract: For taking a characteristic impedance matching of signal transmission lines in a package which carries thereon a semiconductor chip with a very high-speed LSI formed thereon, there is provided a semiconductor integrated circuit device wherein one ends of signal transmission lines formed on a main surface of a package substrate are extended up to the position just under pads formed on a main surface of the semiconductor chip and are connected to the pads on the chip electrically through bump electrodes, while opposite ends of the signal transmission lines are extended to the outer peripheral portion of the main surface of the package substrate and outer leads are bonded thereto.

Abstract: A packaged semiconductor device has a package, a semiconductor IC chip disposed in a space formed in the package, a strip conductor buried at a first level in the package for carrying a signal to be coupled to the IC chip, a first reference potential conductor buried at a second level in the package for providing a reference potential for the IC chip and a second reference potential conductor buried at the first level in the package for shielding the strip conductor. A connection conductor such as a bonding wire is provided across the second reference potential conductor for connecting the IC chip with one of the ends of the strip conductor. A dielectric material is provided between the connection conductor and the second reference potential conductor to provide the connection conductor with a characteristic impedance matched with an impedance of a source of the signal the connection conductor carries.