Method for Producing Metal Ball, Joining Material, and Metal Ball

Patent metadata

Field	Value
Publication number	US-2017182600-A1
Application number	US-201415116275-A
Country	US
Kind code	A1
Filing date	Feb 4, 2014
Priority date	Feb 4, 2014
Publication date	Jun 29, 2017
Grant date	—

Abstract

Produced is a metal ball which suppresses an emitted α dose. Contained are the steps of melting a pure metal by heating the pure metal at a temperature which is higher than a boiling point of an impurity to be removed, higher than a melting point of the pure metal, and lower than a boiling point of the pure metal, the pure metal containing a U content of 5 ppb or less, a Th content of 5 ppb or less, purity of 99.9% or more and 99.995% or less, and a Pb or Bi content or a total content of Pb and Bi of 1 ppm or more, and the pure metal having the boiling point higher than the boiling point at atmospheric pressure of the impurity to be removed; and sphering the molten pure metal in a ball.

First claim

1 . A method of producing a metal ball, characterized in that the method comprises the steps of:
melting a pure metal by heating the pure metal at a heating temperature which is set to be higher than a boiling point of Po to be removed, higher than a melting point of the pure metal, and lower than a boiling point of the pure metal, according to the boiling points and melting point changing depending on the atmosphere, the pure metal containing a U content of 5 ppb or less, a Th content of 5 ppb or less, purity of 99.9% or more and 99.995% or less, and a Pb or Bi content or a total content of Pb and Bi of 1 ppm or more, and the pure metal having the boiling point at atmospheric pressure higher than the boiling point at atmospheric pressure of the Po to be removed among impurities contained in the pure metal; and sphering the molten pure metal into a ball.

2 . The method of producing the metal ball according to claim 1 , wherein the melting point of the pure metal at the atmospheric pressure is 900 degrees C. or higher and the boiling point thereof is 962 degrees C. or higher.

3 . (canceled)

4 . The method of producing the metal ball according to claim 1 , further comprising an annealing step of annealing the sphered metal ball.

5 . A joining material comprising: the metal ball produced by the method according to claim 1 .

6 . A metal ball produced by the method according to claim 1 , wherein the metal ball has an α dose of 0.0200 cph/cm 2 or less and sphericity of 0.90 or more.

7 . A joining material comprising: the metal ball of claim 6 .

8 . The method of producing the metal ball according to claim 2 , further comprising an annealing step of annealing the sphered metal ball.

9 . A joining material comprising: the metal ball produced by the method according to claim 2 .

10 . A joining material comprising: the metal ball produced by the method according to claim 4 .

11 . A joining material comprising: the metal ball produced by the method according to claim 8 .

12 . A metal ball produced by the method according to claim 2 , wherein the metal ball has an α dose of 0.0200 cph/cm 2 or less and sphericity of 0.90 or more.

13 . A metal ball produced by the method according to claim 4 , wherein the metal ball has an α dose of 0.0200 cph/cm 2 or less and sphericity of 0.90 or more.

14 . A metal ball produced by the method according to claim 8 , wherein the metal ball has an α dose of 0.0200 cph/cm 2 or less and sphericity of 0.90 or more.

15 . A joining material comprising: the metal ball of claim 12 .

16 . A joining material comprising: the metal ball of claim 13 .

17 . A joining material comprising: the metal ball of claim 14 .

Assignees

• Senju Metal Industry Co

Inventors

• Kawasaki Hiroyoshi
• Roppongi Takahiro
• Soma Daisuke
• Sato Isamu

Classifications

• H10W72/072

  of bump connectors · CPC title

• H10W72/01271

  Cleaning, e.g. oxide removal or de-smearing · CPC title

• H10W90/724

  between a chip and a stacked insulating package substrate, interposer or RDL · CPC title

• H10W90/722

  between stacked chips · CPC title

• H10W72/255

  of outermost layers of multilayered bumps, e.g. material of a coating · CPC title