Nec Corporation

Motoji Suzuki

Akihiro Tanaka

Hiroshi Sakai

Makoto Igarashi

Shinji Watanabe

Akihiro Sato

Hiroshi Matsuoka

Michinobu Tanioka

Naomi Ishizuka

Eiichi Kono

Akihito Matsumoto

Masafumi Kanai

A structure of the present invention has a printed circuit board having a land portion provided on a surface thereof on which a solder paste is printed in such a condition that, with respect to a lengthwise direction of a connecting terminal of an electronic component to be connected to the land portion, the solder paste projects outward from an edge of the land portion on the side of a front end of the connecting terminal and/or the solder paste is withdrawn toward inside the edge of the land portion on the side of a rear end of the connecting terminal. Solder projecting from the edge of the land portion on the side of the front end of the connecting terminal is used for forming a fillet by which the front end of the connecting terminal is surely covered. Also, as the solder paste is withdrawn from the edge of the land portion on the side of the rear end of the connecting terminal, any extra solder except for the solder indispensable for forming a soldered joint is not generated.

Structure comprising a printed circuit board with electronic components mounted thereon and a method for manufacturing the same

A method of packaging an electronic component having electrodes soldered on lands on a printed circuit board uses a mask pattern that corresponds to the lands onto which solder paste is deposited. Solder paste is printed on the lands using the mask which has a convex shape such that the edges of the solder paste lie inside the edges of the lands. The electrodes are then placed on the solder paste, and the solder paste is caused to reflow to solder the electrodes to the lands.

Method of packaging electronic components without creating unnecessary solder balls

An electronic component that is provided with leads at a narrow pitch that are plated with solder is packaged by soldering the leads to lands on a printed circuit board on which the lands have been formed in a pattern of arrangement that corresponds to said leads. When packaging, solder paste is printed over areas on the lands that are greater in area than the area of the lands. The leads are then placed on this solder paste, and the solder paste is subjected to reflow to solder the leads onto the lands.

Method of packaging electronic components with high reliability

A method of manufacturing a mount structure according to the present invention which forcedly cools down a melted solder paste on a printed circuit board at a cooling speed of 1.5&#xb0; C./second or higher to solidify the solder paste when an electronic part is mounted on the printed circuit board by reflow processing.

Method of manufacturing mount structure without introducing degraded bonding strength of electronic parts due to segregation of low-strength/low-melting point alloy

A printing mask has protrusions having through holes defined therein for printing a solder paste on lands on a printed circuit board. The protrusions serve to increase the amount of solder paste filled in the through holes.

Method and apparatus for printing solder paste of different thickness on lands on printed circuit board

In a circuit board having lands each of which has a through hole through which a lead of an electrical part is inserted, the lead and the land being mounted in the circuit board by using lead-free solder , the width of the land corresponding to the difference in radius between the land and the through hole is set to about 0.40 mm or more. The width of the land is set to such a value that the land exfoliation due to the solidification/shrinkage of the lead-free solder and the shrinkage of the circuit board in the thickness direction can be prevented. The circuit board has circuit wires at least on both the surface and the back surface.

Circuit board and electronic equipment using the same

A sealing resin mixed with filler is used to seal a space between a flip-chip mounted semiconductor device and a printed circuit board. An integrated circuit chip joined to the printed circuit board by metal bumps, has the sealing resin interposed in the space between the chip and the board. The density of the filler in the sealing resin varies such that there is a relatively greater amount of filler at or near the integrated circuit chip. This allows the coefficient of thermal expansion of the resin layer adjacent the chip to better match the coefficient of thermal expansion of the silicon which makes up the chip.

Flip-chip resin sealing structure and resin sealing method

The present invention provides a printed wiring board on which a bear chip is bonded in face-down. The printed wiring board has wiring patterns extending over the printed wiring board, wherein a plurality of wirings are provided which extend radially and outwardly from a center area of the printed wiring board, and wherein each of the wirings comprises at least a bear chip mounting pad region for contacting bumps of the bear chip, at least an external wiring pad region for connecting to an external wiring, and at least a covered region being covered by at least an insulation layer and the covered region separating between the bear chip mounting pad region and the external wiring pad region and a sealing material is filled within a space defined between the printed wiring board and the bear chip.

Printed wiring board

A flux is applied to a circuit board on which solder is deposited beforehand. Then, the circuit board is subjected to reflow and then to rinsing. After the rinsing, an IC chip 1 having metal bumps on its electrodes, is mounted to the circuit board. Before the mounting, the chip 1 and circuit board are heated in an inactive gas atmosphere having a low oxygen concentration. At the time of mounting, the solder is melted at a temperature higher than its melting point so as to connect the chip 1 to the circuit board.

Growing community of inventors

Tokyo, Japan

Motoji Suzuki