Lead-free soldering tin alloying pellet

A technology of lead-free solder and alloy balls, applied in welding medium, welding equipment, metal processing equipment, etc., can solve the problems of lead poisoning and achieve excellent wettability

Inactive Publication Date: 2014-02-19
NINGBO YINZHOU HENGXUN ELECTRONICS MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If humans or livestock drink lead-containing groundwater for a long time, lead can accumulate in the body, which may cause lead poisoning

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0021] The solidus temperature (ST) and liquidus temperature (LT) of each alloy are determined from each other from the heating curves by differential thermal analysis. Solder balls with a diameter of 0.5 mm were prepared by the oil bath method. It can be said that the solder ball is placed in the air of 125 degrees for 12 hours to evaluate its yellowing, and then the degree of yellowing of the surface of the solder ball is visually observed. Solder balls with no yellowing on the surface were rated as good solder balls, those with a little yellowing were moderate, and those with severe yellowing were bad. To evaluate voiding of solder balls, solder balls can be placed on electrodes on a BGA substrate and then heated in a reflow oven containing a nitrogen atmosphere with 100 ppm oxygen or less, where the BGA substrate maintains a peak above the LT temperature The temperature was held at 240°C for 40 seconds to form the solder balls into solder bumps. The inspection device the...

example 2

[0024] In this example, the effect of adding P on solder ball joint reliability was measured before and after aging, ie, before and after exposure to high temperatures, in accordance with the present invention. In this example the solder composition Sn-3.OAg O.SCu solder alloy or Sn-4.OAg O.SCu solder alloy containing 0-400 ppm of P was used to prepare a 0.5 dia. mm of solder balls. The solder balls are placed on the flat surface of the printed circuit board and heated in a reflow oven to form the solder balls into solder bumps. Printed circuit boards can be gold plated or Cu-OSP (organic surface pre-flux). A reflow oven with an oxygen concentration of 100 ppm or less is a nitrogen atmosphere. Reflux was then operated at a peak temperature of 240°C above the liquidus temperature for 40 seconds. The resulting solder bumps were then aged in air at 150°C for 200 hours. Both before and after aging, the solder bumps were subjected to a 2-second tensile test using a beating 4000...

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PUM

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Abstract

The invention discloses a lead-free soldering tin alloying pellet. The lead-free soldering tin alloying pellet is characterized by being formed by a solder pellet component. The solder pellet component comprises, by mass, 1.0-4.0% of Ag, 0.05-2.0% of Cu, 0.0005-0.005% of P, and the balance Sn. The solder pellet component of the lead-free soldering tin alloying pellet preferably contains, by mass, 1.0-3.5% of Ag and 0.05-0.75% of Cu. The diameter of the lead-free soldering tin alloying pellet is 0.04-0.5 millimeter. The lead-free soldering tin alloying pellet is arranged on an electrode of a BGA substrate. The lead-free soldering tin alloying pellet has the advantages that the surface of the lead-free soldering tin alloying pellet can not turn yellow when the lead-free soldering tin alloying pellet forms a soldering tin protruding block on the electrode, packaged through the BGA, of an electronic part, the soldering tin pellet has excellent wettability, gaps can not be formed easily in the welding process, and the diameter of the soldering tin pellet is tiny.

Description

technical field [0001] The invention relates to a solder ball, in particular to a lead-free solder alloy ball. Background technique [0002] In the past, an alloy of Sn and Pb was most commonly used to form solder alloy balls of solder bumps on BGA, especially 63Sn-Pb alloy, which is a eutectic composition of Sn-Pb alloy. It has been found, however, that the use of leaded solder, including leaded solder alloy balls, is a source of environmental contamination. When electronic parts with Sn-Pb solder fail or become obsolete and are no longer convenient for use, they are discarded for disposal. When such equipment is discarded, parts of the equipment can be reused or recycled. For example, plastic in containers, metal in frames and precious metals in electronic parts can often be recycled. In contrast, printed circuit boards with solder are bonded and cannot be reused or recycled. Therefore, discarded printed circuit boards are usually shredded and then buried in landfills ...

Claims

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Application Information

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IPC IPC(8): B23K35/28B23K35/02
CPCB23K35/262B23K35/0244
Inventor 王伟德
Owner NINGBO YINZHOU HENGXUN ELECTRONICS MATERIALS
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