Hitachi, Ltd.

Toru Nishikawa

Masahide Harada

Ryohei Satoh

Tetsuya Hayashida

Mitugu Shirai

Mitsugu Shirai

Masahito Ijuin

Osamu Yamada

Takayuki Uda

Ryohei Sato

Takahiro Daikoku

Yasuhiro Iwata

Kaoru Katayama

Kosuke Inoue

Yuzo Taniguchi

Mitsunori Tamura

Takeshi Miitsu

Masahide Hara

Hiroko Takehara

The present invention is a process for manufacturing an electronic circuit device by applying a solder material to electronic parts or electrodes on a printed circuit board; the process comprising the steps of removing an initial surface oxide film and an organic contaminant film from the surfaces of the solder material and electrode, covering the solder material and an area to which solder is to be applied which is comprised of the electrode, with a liquid vaporizing up after the bonding is completed in the step of heat-melting the solder material, to thereby prevent reoxidation of the joining area surface, and heat-melting the solder material, to carry out solder bonding without using any flux.

Process for manufacturing electronic circuit devices

A multi-chip module is provided with a structure for disposing of a large amount of surplus solder at soldered portions. In this multi-chip module, a cooling member (structure) is soldered directly at the back side of heat generating member such as a semiconductor integrated circuit element. In order to dispose of the surplus solder, the present invention has a first metallized part formed at a cooling member which is larger than a second metallized part formed at the back side of semiconductor integrated circuit element which is solder with the first metallized part.

Multi-chip module

In soldering together two members such as electronic circuit devices, after an oxide or contaminated layer has been removed from the surface of a solder material or bonding pad, for example, the members are aligned in an oxidizing atmosphere. Then the solder material is heated in a nonoxidizing atmosphere to melt the solder and bond the members. Cleaning of the solder material or bonding pad is performed by sputter-cleaning, laser cleaning, mechanical polishing, or cutting.

Method of fabricating an electronic circuit device and apparatus for performing the method

An electronic device is solder bonded properly without using fluxes nor precise positioning with respect to a substrate. A bond pad with a size about twice the size of terminal pad of the electronic device is formed in a region on the substrate where the electronic device is to be mounted. After placing the electronic device of the substrate surface, the whole unit is heated in a nitrogen atmosphere to melt a bump formed on the terminal pad of the electronic device. The molten solder wets and spreads over the bond pads formed on the substrate, thereby establishing reflow soldering between the bond pads and the terminal pads. The position of the electronic device with respect to the substrate is spontaneously corrected due to a self-alignment function induced by wetting and spreading of the molten solder over the bond pad of the substrate.

Electronic device bonding method and electronic circuit apparatus

Method of fabricating an electronic circuit device and apparatus for

A method of soldering used in fabricating an electronic circuit device employs an organic material supplied to at least one of the connecting members to be bonded. The connecting members are positioned in an oxidizing atmosphere, and heated in a nonoxidizing atmosphere to remove oxide and/or contamination layers present on the surface of presoldered portions or metallized bonding portions. By this method, fluxless soldering is performed, positional shifts are reduced, and high reliability of the soldering connections with reduction in residues after reflow are obtained.

Method of fabricating an electronic circuit device

An apparatus comprises a sputter cleaning device, an alignment device operable in atmospheric condition and a heating and soldering device in the form of a belt furnace operable in non-oxidizing or reducing environment. Instead of the sputter cleaning device, a mechanical polishing or cutting device can be used to clean a surface of solder or a member to be bonded or a solder ball plated with gold may be used. An alignment between two members to be bonded is provided by an alignment mark means which comprises a protrusion on a surface of one member and a complimentary recess formed at a center portion of a protrusion means formed on a corresponding surface of the other member.

Method of fabricating electronic circuit device and apparatus for

In order to remove oxide film and contamination film on members to be bonded by soldering and solder material therefor corresponding to variation of thickness thereof by sputter-etching in a fluxless bonding method and apparatus therefor, substance emitted from the solder material under sputter-etching using atom or ion is detected and determined whether it is from the solder material or from the oxide film thereon. The sputter-etching is controlled on the basis of the determination to remove the oxide film. Then, the members are aligned in oxidizing atmosphere and soldered in non-oxidizing atmosphere.

Soldering method and apparatus for use in connecting electronic circuit

In a method of soldering for use in fabricating electronic circuit device, after an oxide layer and/or contaminated layer on a surface of a soldering material and members to be soldered thereby is removed by sputter-cleaning with atom or ion, the members are aligned in an oxidizing atmosphere within a predetermined time period and, then, the soldering material is heated in non-oxidizing atmosphere to performe soldering. An apparatus for performing the above method comprises a sputter cleaning device, an alignment device operable in atmospheric condition and a heating and soldering device in the form of a belt furnace operable in non-oxidizing or reducing environment. Instead of the sputter cleaning device, a mechanical polishing or cutting device can be used to cleaning a surface of solder or a member to be bonded or a solder ball plated with gold may be used. An alignment between two members to be bonded is provided by an alignment mark means which comprises a protrusion on a surface of one member and a complimental recess formed at a center portion of a protrusion means formed on a corresponding surface of the other member.

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Yokohama, Japan

Toru Nishikawa