Nippon Steel Corporation

Other

Nippon Hoso' Kyokai

Ball Semiconductor Corporation

Nippon Steel Materials Co., Ltd.

Kenji Shimokawa

Eiji Hashino

Kohei Tatsumi

Nobuo Takeda

Atsuyuki Fukano

Kouhei Tatumi

Hitoshi Dohnomae

Toshio Mukai

Kengo Shimanoe

Norikazu Kawamura

Balls are sucked onto a carrier board so as to be temporarily arranged in a ball arrangement region of the board, and then the balls are transferred and bonded onto an objective substance with their positions being adjusted. Gas blow is applied to the temporarily arranged balls or alternatively the temporarily arranged balls are sucked, so as to remove excess balls other than balls that have been exactly sucked onto the ball arrangement region. Cooperation with application of fine vibration to the carrier board makes the removal of the excess balls more efficient.

Ball transferring method and apparatus

A semiconductor device () comprising electrodes formed on a semiconductor chip () and bumps () which consist of a low melting point metal ball spherically formed and having a given size and which are adhesive bonded to the electrodes (). The electrodes () are formed from an electrode material of Cu or a Cu alloy, Al or an Al alloy, or Au or a Au alloy. When the electrode material is composed of Al or an Al alloy, the electrodes contain, on the electrode material layer of Al or an Al alloy, at least one layer () composed of a metal or metal alloy (preferably a metal selected form Ti, W, Ni, Cr, Au, Pd, Cu, Pt, Ag, Sn or Pb, or an alloy of these metals) having a melting point higher than the electrode material. The low melting point metal balls () are adhesive bonded to the electrodes () preferably with a flux. The low melting point metal balls () adhesive bonded to the respective electrodes () may also be reflowed to form semispherical bumps () before use.

Method for fabricating a semiconductor devices provided with low melting point metal bumps

Semiconductor device provided with low melting point metal bumps

A spherical semiconductor device includes a spherical semiconductor element having one or more electrodes on its surface. Spherical conductive bumps are formed at the positions of the electrodes. The electrodes are so arranged as to contact a common plane. Spherical bumps constituting a group to be connected to the outside protrude above the spherical semiconductor element such that a predetermined gap is formed between a plane or a spherical surface capable of contacting the spherical bumps and the surface of the spherical semiconductor element. The spherical semiconductor device is connected to various circuit boards or another semiconductor device through the spherical bumps. This affords easy and accurate electrical connections to the outside.

Spherical semiconductor device and method for fabricating the same

The object of the present invention is to provide a free and precise control of the plating amount while easily determining a selected portion to be plated. Small ballsare arranged at, and adhered or bonded to, via holesof a TAB tapeand the small ballsare then melted so that a copper wiringexposed at the via holesof the TAB tapecan be selectively plated with a different metal to enable selected portions of a substrate for electronic devices to be partially plated easily and precisely.

Method of partially plating substrate for electronic devices

A ball-arranging substrate comprising a substrate with a main surface, a plurality of ball-arranging holes formed on the main surface for sucking and holding minute electroconductive balls at the locations corresponding to those of electrodes formed on a semiconductor device or a printed circuit board, wherein when light illuminates the ball-arranging surface to allow optical recognition of the arrangement of the minute electroconductive balls by means of the light reflected by the minute electroconductive balls and by the main surface, the wave length of the light of the light source is set in the range of 300 to 900 nm, and the reflectivity is made not more than 50% based on the light source. A reflective mirror should be provided on the rear surface of the substrate opposite to the light source, in the case when the substrate is transparent to the irradiated light.

Ball-arranging substrate for forming bump, ball-arranging head, ball-arranging device, and ball-arranging method

A process of transferring a flux on electrodes of a semiconductor chip, a film carrier, or a substrate, the process comprising: using a transfer apparatus including a transfer baseplate having protrusions corresponding to said electrodes; dipping the tips of the protrusions of the transfer baseplate in a flux bath to cause the flux to stick to the tips; then aligning the protrusions of the transfer baseplate with the electrodes; and transferring the stuck flux onto the electrodes from the tips.

Transfer of flux onto electrodes and production of bumps on electrodes

A process of producing small metal bumps includes the steps of simultaneously holding small metal balls on an arrangement baseplate in the positions corresponding to those of electrodes of a semiconductor chip, a film carrier, or a substrate; aligning the small metal balls held on the arrangement baseplate with the electrodes; lightly pressing the small metal balls against the electrodes; to provisionally fix the balls to the electrodes; and pressing the provisionally fixed small metal balls to flatten the pressed surfaces of the small metal balls, and at the same time, to bond the small metal balls to the electrodes.

Production of small metal bumps

A high density magneto-optical recording medium utilizing a polycrystalline garnet two-layer film. The film thickness of an under layer of the garnet polycrystal on a glass substrate is made 100 nm or less, and a crystal grain diameter of a recording layer formed thereon is made 0.1 .mu.m or less. Furthermore, the under layer is demagnetized at room temperature. With this, a bit having a regular shape can be written, thus reducing medium noise by a large margin.

Magneto-optical recording medium, disk and method of manufacturing the

A garnet polycrystalline film for a magneto-optical recording medium including at least two layers of polycrystalline garnet represented by Bi.sub.x R.sub.3-x M.sub.Y Fe.sub.5-Y O.sub.12, where 0.ltoreq.X.ltoreq.3, 0 Y.ltoreq.5, R represents one or more rare earth elements containing yttrium, and M represents Ga, Al or In, wherein crystal lattice constants of these adjacent two layers are different from each other by .+-.0.3% or more, and an average crystal grain diameter of one of the layers is smaller than that of the other layer and 1 .mu.m or less, and a magneto-optical recording disk using this garnet polycrystalline film.

Growing community of inventors

Chiba, Japan

Kenji Shimokawa