METAL AND TIN ALLOY HAVING LOW alpha-RAY EMISSION, AND METHOD FOR PRODUCING SAME

A manufacturing method, α-ray technology, applied in the manufacture of tools, metal processing, metal processing equipment, etc., can solve the problems of unguaranteed, unrealizable, and increased occurrence of soft errors, and achieve the effect of reliable precipitation removal

Active Publication Date: 2020-04-17
MITSUBISHI MATERIALS CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0011] On the other hand, in recent years, it has been reported that when a chip bonded to a substrate by solder is exposed to a high-temperature environment, the occurrence rate of soft errors increases compared with the initial stage of use (for example, refer to Non-Patent Document 1 (Abstract, abstract))
[0022] Therefore, in the method of Patent Document 2, there is no guarantee that it can be used as a raw material tin with a high Pb concentration as an impurity, and when the Pb concentration in the raw material tin becomes high, it may not be possible to achieve 0.001 cph / cm. 2 The amount of α-ray emission below the level

Method used

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  • METAL AND TIN ALLOY HAVING LOW alpha-RAY EMISSION, AND METHOD FOR PRODUCING SAME
  • METAL AND TIN ALLOY HAVING LOW alpha-RAY EMISSION, AND METHOD FOR PRODUCING SAME
  • METAL AND TIN ALLOY HAVING LOW alpha-RAY EMISSION, AND METHOD FOR PRODUCING SAME

Examples

Experimental program
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Effect test

no. 1 Embodiment approach ＞

[0056] First, follow the figure 1 sequence of steps shown and according to image 3 The production apparatus shown is a description of the production method of any one of tin, silver, copper, zinc, and indium (metal material for solder material) with low α-ray emission according to the first embodiment of the present invention.

[0057]

[0058] 〔Metal raw material〕

[0059] Regarding any one of tin, silver, copper, zinc and indium used to obtain the low α-ray emission of the first embodiment ( figure 1 Indicated by M in ), the selection of metal raw materials is not limited according to the Pb content of impurities or the amount of α-ray emission.

[0060] For example, even if the concentration of Pb is about 320 mass ppm and the amount of α-ray emission based on Pb is 9 cph / cm 2 A commercially available tin metal of about 100°C is used as the metal raw material, and in the above-mentioned metal finally obtained by using the manufacturing method and manufacturing apparatus...

no. 2 Embodiment approach ＞

[0090] Next, a method for producing a low-α-ray-emitting tin alloy according to a second embodiment of the present invention will be described.

[0091] In this manufacturing method, the metal tin (Sn) with low α-ray emission obtained in the first embodiment and one or more than two selected from silver, copper, zinc, indium, bismuth, nickel, and germanium metals are cast to make tin alloys.

[0092] Here, as the metal that forms an alloy with metal tin, when a tin alloy is used as solder, silver, copper, zinc, and indium are preferable from the viewpoint of the melting point and mechanical properties of the solder. In order to realize the purpose of the present invention, the α-ray emission of silver, copper, zinc, indium, bismuth or nickel alloyed with metal tin is 0.002cph / cm 2 the following.

[0093] In addition, in this embodiment, casting can utilize the furnace normally used for casting, such as a high-frequency induction melting furnace, for example. In addition, exam...

Embodiment

[0096] Next, examples of the present invention will be described in detail together with comparative examples.

[0097]

[0098] As a metal raw material, use an alpha ray emission of 10.2cph / cm 2 A commercially available Sn powder with a Pb concentration of 15 ppm was added and mixed to an aqueous sulfuric acid solution with a concentration of 130 g / L stored in a tin sulfate preparation tank, and dissolved at 50° C. to prepare 1 m 3 200g / L tin sulfate aqueous solution. Thereby, Pb contained in the tin of the metal raw material is precipitated as lead sulfate. The tin sulfate aqueous solution was filtered through a membrane filter (pore size: 0.2 μm) manufactured by Yuasa Membrane Systems Co., Ltd. to remove lead sulfate.

[0099] Next, in the first tank, while stirring the tin sulfate aqueous solution from which lead sulfate has been removed at a speed of 100 rpm, add a solution containing α-ray emission amount of 5cph / cm 2 lead nitrate aqueous solution of Pb (lead nitra...

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Abstract

Provided is a metal which is one of tin, silver, copper, zinc, or indium, and has low alpha-ray emission, wherein the alpha-ray emission of the metal after being heated in air at 100 DEG C for 6 hoursis 0.002 cph / cm<2> or less. A metal selected from among tin, silver, copper, zinc, and indium, each of which contains lead as an impurity, is dissolved in an aqueous sulfuric acid solution to preparean aqueous solution of a sulfate of the metal, and lead sulfate in the aqueous solution is removed by precipitation. While stirring the aqueous sulfate solution from which lead sulfate has been removed, an aqueous lead nitrate solution containing lead having an alpha-ray emission of 10 cph / cm<2> or less is added to the aqueous sulfate solution to precipitate lead sulfate in the aqueous sulfate solution, and the aqueous sulfate solution is circulated while removing lead sulfate. The metal is electrolytically collected using the aqueous sulfate solution as an electrolytic solution.

Description

technical field [0001] The present invention relates to any one metal among tin, silver, copper, zinc or indium which emits very little α-rays and is suitable for solder materials for manufacturing electronic parts and which emits very little α-rays. Furthermore, it relates to an alloy (hereinafter referred to as a tin alloy) of one or more metals selected from silver, copper, zinc, indium, bismuth, nickel, and germanium and tin with a low α-ray emission. Moreover, it also relates to each manufacturing method of the metal or tin alloy which emits these low-alpha rays. [0002] This application claims priority based on Patent Application No. 2017-157394 filed in Japan on August 17, 2017 and Patent Application No. 2018-142195 filed in Japan on July 30, 2018, and the contents thereof are incorporated herein. Background technique [0003] As a solder material for electronic parts, lead (Pb) has an impact on the environment. Solder materials that are mainly metals such as Pb-fre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25C1/14C22B11/00C22B15/14C22B19/32C22B25/08C22B58/00C25C1/12C25C1/20C25C1/22
CPCB23K35/262C22B11/00C22B19/32C22B25/08C22B58/00C22C13/00C25C1/12C25C1/14C25C1/16C25C1/20C25C1/22B23K2101/40C22B13/08C22C2202/00
Inventor 平野广隆吉田能弘片濑琢磨
Owner MITSUBISHI MATERIALS CORP
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