Ngk Spark Plug Company, Limited

Mitsuo Shiraishi

Hajime Saiki

Kazuo Kimura

Kazuhiro Urashima

Hiroshi Sumi

Tatsuharu Ikawa

Yosuke Kondo

A wiring substrate comprised of a substrate main body made of glass-ceramic, a pad formed on a surface of the substrate main body and a conductor pin provided in an upright position on the pad. The pad is comprised of a ceramic that is the same as the ceramic constituting the glass-ceramic, Fe converted into FeOand Cu. The FeOcomprises 1 to 28 parts by weight with respect to 100 parts by weight of the Cu.

Wiring substrate and bonding pad composition

In a resinous circuit board having a circuitized substrate having conductive layers therewithin, a plurality of pin pads formed on a rear surface of the substrate, and a plurality of pins, each pin having a tip end portion and a head portion and soldered to the pin pad in such a manner as to contact at the head portion to the pin pad. The head portion of the pin consists of a flange section which is larger in diameter than the tip end portion, and a part-spherical abutment section bulging from the flange section in the direction opposite to the tip end portion and brought into contact with the pin pad. The part-spherical abutment section is made of eutectic silver solder which is lower in melting point than solder such as Sn&mdash;Ag solder which is used for soldering the pin to the pin pad. Since the silver solder and soft solder are present between the flange section and the pin pad, they can release the stress applied to the pin, thus making it possible to increase the joining strength considerably. Further, the above structure can dispense with holes which are formed in the circuitized substrate and in which pins are press-fitted and fixed as in the prior art circuit board.

Resinous circuit board with pins improved in joining strength

A printed-wiring substrate including a substrate having pin-bonding portions formed on a main surface thereof and lead pins . The lead pins each have a flange and a shaft portion and being brazed to corresponding pin-bonding portions via the corresponding flanges . A hemispherical convex shape is imparted to a bonding surface of a flange . The flange is used for brazing of a lead pin , and the bonding surface faces a pin-bonding portion of a substrate . A brazing filler metal used for brazing of the lead pin extends by wetting toward the tip end of the lead pin beyond the outermost edge of an opposite surface of the flange , which is opposite the bonding surface of the flange , such that an extension-by-wetting end of the brazing filler metal is located between the outermost edge and a shaft portion of the lead pin . Since the solder has no narrow portion, the bonding strength is not impaired.

Growing community of inventors

Aichi, Japan

Mitsuo Shiraishi