Solder alloy, solder ball, and solder joint using the same

a technology of solder ball and alloy, which is applied in the direction of soldering apparatus, manufacturing tools, and capacitors, can solve the problems of increasing melting point and thermal damage to semiconductor packages, and achieve the effect of suppressing a decrease in joint strength, reducing metallic luster, and not impairing the ductility of sn—cu alloy

Inactive Publication Date: 2007-06-07
HITACHI METALS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0019] The invention greatly solve problems of a decrease in metallic luster attributable to a bad surface texture and failure in mounting of solder balls, without impairing ductility of a Sn—Cu

Problems solved by technology

On the other hand, when the amount of Cu exceeds 0.75 mass %, an increase in melting point is brought about, and

Method used

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  • Solder alloy, solder ball, and solder joint using the same
  • Solder alloy, solder ball, and solder joint using the same
  • Solder alloy, solder ball, and solder joint using the same

Examples

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Effect test

example 2

[0055] Subsequently, solder balls having a diameter of 0.3 mm were used to form solder bumps on an electrode (referred below to as Ni electrode), which was provided by performing electrolytic Ni / Au plating on a Cu substrate, and reliability in solder joint was evaluated. The electrode had a diameter of 0.25 mm. Soldering was performed by heating to 240° C. and in order to evaluate a deterioration behavior in high-temperature environment, samples, which were annealed at 150° C. for 100 hours after soldering, were also fabricated. With respect to the samples fabricated in this manner, spalling of a Cu—Ni—Sn compound formed on a joint interface was confirmed and a cross-sectional structure was observed for measurement of a thickness of the compound. An area of an interface compound in a cross-sectional structure photograph was measured by means of image processing, and a thickness of a Cu—Ni—Sn compound was calculated as a thickness per unit length of a joint interface. TABLE 3 indicat...

example 3

[0061] In order to evaluate a drop impact strength, bound-level drop test was carried out on the basis of the JEDEC Standards JESD22-B111. Test substrates for the drop test were fabricated by using solder balls having a diameter of 0.3 mm to form solder bumps on BGA having 345 Ni electrodes and then using a solder paste to join the solder bumps to a mother board.

[0062] Sn-3Ag-0.5Cu (by mass %) as generally used was used for the solder paste. Subsequently, after a test substrate was fixed horizontally to a drop table, it was dropped 30 times from a level, at which level a drop impact applied to the drop table was 1500 G to form a half-sine wave of 0.5 ms, while being maintained in a horizontal posture. In the drop test, bias of a daisy-chain circuit formed between BOA and the mother board was measured to find electrical failure. For respective compositions of solder, two test substrates, that is 30 BGAs in total, were evaluated, since 15 BGAs were mounted every test substrate.

[0063...

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Abstract

A solder alloy is provided, which consists of, by mass %: 0.6 to 0.75% of Cu; 0.3 to 1.5% of Ag; more than 0.01% but not more than 0.1% of Ge; and the balance being Sn and incidental impurities. Preferably an amount of Ag is 0.5 to 1 mass % Preferably, an amount of Ge is more than 0.01 mass % but not more than 0.06 mass %. The solder alloy is preferably spherically formed into a solder ball. A solder joint in which the solder alloy is joined to a Ni electrode is also provided.

Description

TECHNICAL FIELD [0001] The present invention relates to a solder alloy used in soldering of electronic parts, etc., a solder ball, and a solder joint. BACKGROUND OF THE INVENTION [0002] In recent years, as mobile devices such as cellular phone, etc. are decreased in mount area, there is a tendency of miniaturization in semiconductor packages. A mount configuration, in which a semiconductor package is connected to a mother board, has undergone changes to a type in which electrodes are formed area array package, from a peripheral type in which conventional lead-frame is used. BGA (Ball Grid Array) is a typical one and its electrodes are joined to a mother board by means of spherically formed solder, that is, solder balls. [0003] Different external forces are sometimes applied to a semiconductor package. For example, a drop impact is listed as an external force peculiar to mobile devices. This is because a mobile device is carelessly dropped when it is used or carried. With conventiona...

Claims

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Application Information

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IPC IPC(8): C22C13/00H01L33/06H01L33/32H01L33/34H01L33/48H01L33/50
CPCB23K35/262C22C13/00H01B1/026
Inventor DATE, MASAYOSHIFUJIYOSHI, MASARU
Owner HITACHI METALS LTD
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