Hitachi Metals, Ltd.

Nobuhiko Chiwata

Motoki Ohta

Motoki Wakano

Takeyuki Itabashi

Hisashi Tanie

Tetsuro Kato

Minoru Yamada

Shin Noguchi

Takayuki Moriwaki

Shuji Yamanaka

A crystalline Fe-based alloy powder composed of Fe-based alloy particles containing, within a structure thereof, nanocrystal grains having an average grain size of 30 nm or less, and in which d50, which is a particle diameter corresponding to a cumulative frequency of 50% by volume, is from 3.5 &#x3bc;m to 35.0 &#x3bc;m in a cumulative distribution curve that is obtained by laser diffractometry and that shows the relationship between the particle diameter and the cumulative frequency from the small particle diameter side, and a ratio of Fe-based alloy particles having a particle diameter of 2 &#x3bc;m or less to the total of the Fe-based alloy particles, which is determined by laser diffractometry, is from 0% by volume to 8% by volume.

Crystalline Fe-based alloy powder and method for producing same

An alloy powder having an alloy composition represented by FeCuSiBCrSnC, wherein a, b, c, d, e and f are atomic % meeting 0.80&#x2264;a&#x2264;1.80, 2.00&#x2264;b&#x2264;10.00, 11.00&#x2264;c&#x2264;17.00, 0.10&#x2264;d&#x2264;2.00, 0.01&#x2264;e&#x2264;1.50, and 0.10&#x2264;f&#x2264;0.40.

Alloy powder, fe-based nanocrystalline alloy powder and magnetic core

A Fe-based nanocrystalline alloy powder having an alloy composition represented by the following Composition Formula (1) and having an alloy structure including nanocrystal particles:FeCuSiBMoCrCNb&#x2003;&#x2003;Composition Formula (1),

Fe-based nanocrystalline alloy powder, method of producing the same, Fe-based amorphous alloy powder, and magnetic core

A method for producing a ceramic circuit board comprising the steps of bonding a metal sheet to a ceramic substrate via a brazing material containing Ag to form a bonded body; etching the bonded metal sheet to form a circuit pattern; and removing an unnecessary brazing material from the substrate provided with the circuit pattern, by etching with an acidic solution comprising carboxylic acid and/or carboxylate and hydrogen peroxide.

Method for producing ceramic circuit board

A semiconductor device having stacked semiconductor chips is provided wherein alignment of even thin semiconductor chips of a large warpage is easy and thus high assembling accuracy and high reliability are ensured. Semiconductor chips having hollow through-silicon via electrodes each formed with a tapered portion are melt-joined using solder balls each having a core of a material higher in melting point than solder. When melt-joining the semiconductor chips, the temperature is raised while imparting an urging load to stacked semiconductor chips, thereby correcting warpage of the semiconductor chips. In each chip-to-chip connection thus formed, if the connection is to prevent the occurrence of stress around the electrode due to the urging load, a solder ball having a core of a smaller diameter than in the other connections is used in the connection.

Semiconductor device including arrangement to control connection height and alignment between a plurity of stacked semiconductor chips

A novel structure capable of reducing the stress in the insulating layer in the semiconductor element and thereby securing reliability is provided. When the semiconductor element and the substrate are connected with a solder, the stress generated in the insulating layer is reduced by placing a spherical core made of a material having a greater rigidity inside the solder and satisfying the following inequalities: 1 GPa&#x3c;(Young's modulus of a encapsulation resin)&#x3c;30 GPa, 20 ppm/k&#x3c;(linear coefficient of expansion of the encapsulation resin)&#x3c;200 ppm/k, and 10 MPa&#x3c;(yield stress of the solder at room temperature)&#x3c;30 MPa. At the time of connection, the thickness of the solder to be placed between the land on the surface of the semiconductor element and the core is adjusted to 1/10 or less of the terminal pitch.

Semiconductor device

The invention provides a solder alloy containing, by mass, 2.0 to 15.0% of Ag, 0.1 to 6.0% of Al, 0.01 to 0.50% of Y, the balance being Sn and unavoidable impurities. The solder alloy preferably contains 0.01 to 0.50% of Ge by mass. The solder alloy of the invention is suited to bonding oxides together and the oxides preferably comprise glass. The invention provides a glass bonded body formed by bonding glasses with the use of the solder alloy.

Solder alloy and glass bonded body using the same

The invention provides a solder alloy for bonding an oxide material, including more than 0% but not more than 1.0% of Mg and the balance being substantially Bi and Sn. Preferably, the alloy includes 0.01 to 0.6% of Mg, 35 to 86% of Bi, and the balance being substantially Sn. The invention can be used for bonding an oxide material, such as bonding glasses to each other. According to the invention, a low-cost solder joint of an oxide material is also provided.

Solder alloy for bonding oxide material, and solder joint using the same

An object of the present invention is to provide a producing method by which minute metal balls having a high sphericity or roundness and a uniform diameter. The present invention provides a method of producing minute metal balls, comprising the steps of cutting a wire material having a diameter &#x3c6; at predetermined distances to provide metal pieces having a cut length L equal to or smaller than 2 mm and a ratio L/&#x3c6; in a range of 0.1&#x2266;L/&#x3c6;&#x2266;3.0, and introducing the metal pieces into a plasma flame to spheroidize the metal pieces. In the present invention, it is preferable that the metal pieces are made of any metal selected from the group consisting of Cu, Ag, Au and Al, or an alloy as a main of any of these metals. It is also preferable that the metal pieces are made of any metal selected from the group consisting of Fe, Ti, W, Ni and Cr, or an alloy as a main of any of these metals. In addition, it is preferable that the metal pieces are introduced into the plasma flame forming a reducing atmosphere; that 1 to 20% by mass of a hydrogen gas is contained in a plasma operating gas for generating the plasma flame; and that RF plasma is used as the plasma flame.

Growing community of inventors

Yasugi, Japan

Nobuhiko Chiwata