Unlock instant, AI-driven research and patent intelligence for your innovation.

Lead-free soft solder having improved properties at elevated temperatures

A technology of soft solder and solder, applied in the direction of welding/cutting media/materials, welding media, manufacturing tools, etc., can solve problems such as deformation and unsuitability for chip manufacturing, and achieve improved reliability, excellent temperature change tolerance, temperature Effect of Transformation Tolerance Improvement

Active Publication Date: 2009-10-21
HERAEUS MATERIALS TECHNOLOGY GMBH & CO KG
View PDF5 Cites 17 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The high indium content makes the solder alloy very soft and deformed (voids), so that the indium alloy used to make the solder balls is not suitable for chip manufacturing

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Lead-free soft solder having improved properties at elevated temperatures
  • Lead-free soft solder having improved properties at elevated temperatures
  • Lead-free soft solder having improved properties at elevated temperatures

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0065] Tin 95.49, Silver 2, Copper 0.5, Indium 2, Neodymium 0.01, in addition to showing other improved mechanical properties relative to Comparative Example 4, also show Cu 3 The formation of Sn-phase is suppressed and shows less increase of this phase at temperatures above 150°C. Thereby, with the example according to the present invention, the material fatigue is slowed down with a rapid onset, at the same time as superior mechanical properties.

[0066] When the neodymium doping from Example 1 according to Comparative Example 5 was not performed, although Cu 3 The formation of Sn-phase is initially rare, but Ag 3 Sn-phase tends to grow and form rough plates or needles at temperatures above 150°C and thus lead to unacceptable material fatigue and due to Ag 3 The risk of short circuit due to the crystal growth of Sn.

[0067] Example 2 with a 1% increase in indium concentration relative to Example 1 resulted in other improved mechanical properties. Cu 3 The formation of...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
melting pointaaaaaaaaaa
melting pointaaaaaaaaaa
melting pointaaaaaaaaaa
Login to View More

Abstract

Disclosed is a lead-free soft solder based on an Sn-In-Ag solder alloy. The soft solder contains 88 to 98.5 percent by weight of Sn, 1 to 10 percent by weight of In, 0.5 to 3.5 percent by weight of Ag, and 0 to 1 percent by weight of Cu, and is doped with a crystallization modifier, particularly a maximum of 100 ppm of neodymium. The soft solder further contains 0 to 3 percent of GA, Sb, Bi and has a fusion temperature exceeding 210 DEG C, high resistance to fatigue at elevated temperatures, and little growth of intermetallic phases. The disclosed alloy can be used for soldering electronic components in wafer bumping technology.

Description

technical field [0001] The present invention relates to a soft solder for the subject which has an application range up to 200°C, in particular at 150 to 190°C. Background technique [0002] At such high temperatures, tin-silver-copper-(SAC)-solder joints age particularly rapidly due to the growth of intermetallic phases. At high temperatures, the tensile strength is less and the ductility limit deteriorates due to material fatigue, which occurs with the growth of intermetallic phases. [0003] According to EU Directive 2002 / 96 / EG "Waste Electrical and Electronic Equipment" = WEEE und 2002 / 95 / EG "Restriction of the use of certain hazardous substances in electrical and electronic equipment" = RoHS (http: / / ec.europa.eu / environment / waste / weee_index.htm), the application of lead-containing solder is strongly restricted and the application of lead-free solder is essentially regulated. Thus, solders with a lead content of up to 0.1% by weight are considered lead-free. [0004]...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/26C22C13/00
CPCC22C13/00B23K35/262H01L2924/3651B23K1/0016B23K35/22B23K35/24B23K2101/36
Inventor 温弗里德·克雷默约尔格·特罗德勒
Owner HERAEUS MATERIALS TECHNOLOGY GMBH & CO KG