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Researchers Submit Patent Application, "Metal Core Solder Ball and Heat Dissipation Structure for Semiconductor Device Using the Same", for Approval

July 23, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors CHU, Yong Cheol (Ulsan, KR); LEE, Hyun Kyu (Ulsan, KR); KWAK, Jung Ug (Ulsan, KR); LEE, Seung Jin (Ulsan, KR); JEON, Sang Ho (Ulsan, KR); CHOI, Yong Sik (Ulsan, KR), filed on November 18, 2013, was made available online on July 10, 2014.

The patent's assignee is Duksan Hi-metal Co., Ltd.

News editors obtained the following quote from the background information supplied by the inventors: "The present invention relates to a metal core solder ball and a heat dissipation structure for a semiconductor device using the same.

"Useful as a next-generation high density package is a chip scale package (CSP) or a ball grid array (BGA), each of which has high mounting density. Typically, a solder ball is used to electrically connect a chip and a substrate.

"Ensuring electrode reliability upon using a solder ball is considered important. To this end, a metal core solder ball comprising an inner core made of metal and a solder layer formed thereon is recently available, instead of the conventional solder ball. This is because the inner core of a metal core solder ball is not melted at a reflow temperature upon flip chip bonding, and a distance between a chip and a printed circuit board (PCB) is maintained thus obtaining high bonding reliability.

"Meanwhile, because chips having high-density circuits thereon are manufactured these days, heat generated from semiconductor devices should be dissipated to the outside, which is regarded as very important. Conventionally, heat is dissipated in such a manner that a heat sink is provided to the semiconductor device. As such, TIM (Thermal Interface Material) is disposed at the interface between the heat sink and the semiconductor device, whereby heat is efficiently emitted from the semiconductor device to the heat sink.

"However, no attempts have been made to dissipate heat generated from the semiconductor device toward the substrate thorough research thereto is insufficient. This is because when heat is emitted toward the substrate including many electronic elements, it may affect the electronic elements or heat conductivity of the solder ball which connects the substrate and the semiconductor device."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "Accordingly, the present invention has been made keeping in mind the above problems occurring in the related art, and an object of the present invention is to provide a metal core solder ball having high heat conductivity between a semiconductor device and a substrate to impart connection reliability between the semiconductor device and the substrate and to efficiently emit heat generated from the semiconductor device.

"An aspect of the present invention provides a metal core solder ball, comprising a metal core having a diameter of 40.about.600 .mu.m; a first plating layer formed on the outer surface of the metal core; and a second plating layer formed on the outer surface of the first plating layer, and satisfying the following Relation 1:

"1/6a
"wherein a is heat conductivity of the metal core, b is heat conductivity of the first plating layer, c is heat conductivity of the second plating layer, A, B and C are volume ratios of the metal core, the first plating layer and the second plating layer, respectively, in the solder ball, A+B+C=1, 0.0005
"As such, the metal core preferably comprises a metal selected from the group consisting of copper (Cu), silver (Ag), gold (Au) and aluminum (Al).

"As such, the first plating layer is preferably formed by subjecting nickel (Ni) or a Ni alloy to electroless plating.

"Furthermore, the second plating layer is preferably formed by electroplating a tin (Sn) alloy.

"Another aspect of the present invention provides a heat dissipation structure for a semiconductor device, comprising the metal core solder ball as above.

"As such, the heat dissipation structure is preferably configured such that the metal core solder ball is provided to connect the connection terminal of the semiconductor device and the electrode of a substrate.

"As such, a bonding portion which connects the solder ball to the electrode preferably contains brass powder or silver powder.

"A further aspect of the present invention provides an electronic device, comprising a connection terminal of a semiconductor device; an electrode of a substrate disposed to face the connection terminal; and a solder ball which thermally and electrically connects the connection terminal and the electrode of the substrate and satisfies the following Relation 1:

"1/6a
"wherein a is heat conductivity of a metal core, b is heat conductivity of a first plating layer, c is heat conductivity of a second plating layer, A, B and C are volume ratios of the metal core, the first plating layer and the second plating layer, respectively, in the solder ball, A+B+C=1, 0.0005
"As such, the electronic device preferably includes a bonding portion formed of brass powder or Ag powder between the electrode of the substrate and the solder ball.

BRIEF DESCRIPTION OF THE DRAWINGS

"The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

"FIG. 1 illustrates a heat dissipation structure for a semiconductor device using a metal core solder ball according to the present invention;

"FIG. 2 illustrates the results of drop impact testing of Examples 1 to 3 and Comparative Examples 1 to 3; and

"FIG. 3 illustrates the results of observing Kirkendall voids in Example 1 and Comparative 1."

For additional information on this patent application, see: CHU, Yong Cheol; LEE, Hyun Kyu; KWAK, Jung Ug; LEE, Seung Jin; JEON, Sang Ho; CHOI, Yong Sik. Metal Core Solder Ball and Heat Dissipation Structure for Semiconductor Device Using the Same. Filed November 18, 2013 and posted July 10, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=6189&p=124&f=G&l=50&d=PG01&S1=20140703.PD.&OS=PD/20140703&RS=PD/20140703

Keywords for this news article include: Electronics, Semiconductor, Duksan Hi-metal Co. Ltd.

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Source: Electronics Newsweekly


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