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Lead-free solder, lead-free solder ball, solder joint using the same, and semiconductor circuit having the same

A technology of lead-free solder and solder joints, which is applied in semiconductor devices, semiconductor/solid-state device manufacturing, semiconductor/solid-state device components, etc., and can solve problems affecting the reliability of electronic circuits, etc.

Active Publication Date: 2018-06-29
SENJU METAL IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

On the other hand, there is a difference in thermal expansion coefficient of about 5 times between the package (semiconductor chip 2) in the WL-CSP chip 20 and the circuit board 7
Therefore, the impact on the thermal fatigue resistance of the bonding solder due to the repetition of cold and warm is much greater for the WL-CSP chip 20, which greatly affects the reliability of the electronic circuit.

Method used

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  • Lead-free solder, lead-free solder ball, solder joint using the same, and semiconductor circuit having the same
  • Lead-free solder, lead-free solder ball, solder joint using the same, and semiconductor circuit having the same
  • Lead-free solder, lead-free solder ball, solder joint using the same, and semiconductor circuit having the same

Examples

Experimental program
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Embodiment

[0045] Next, the lead-free solder of the present invention will be described with reference to examples. The present invention is a five-element lead-free solder containing Sn, Ag, Cu, Bi, and Ni, and its addition amount is: Ag: 1.2 to 4.5% by mass, Cu: 0.25 to 0.75% by mass, Bi: 1 to 5.8% by mass %, Ni: 0.01 to 0.15% by mass, and the balance is Sn.

[0046] (1) Regarding the amount of Ag added (1.2 to 4.5% by mass)

[0047] The amount of Ag added is preferably not less than 1.2% by mass and not more than 4.5% by mass (1.2≦Ag≦4.5).

[0048] Ag and Sn form intermetallic compound Ag 3 Sn contributes to improvement of thermal fatigue resistance (heat cycle resistance). Ag also has the effect of improving the wettability of the soldered part during soldering and lowering the liquidus temperature.

[0049] When the amount of Ag added is less than 1.2% by mass (Ag<1.2), the wettability (wet spread) decreases, and when it exceeds 4.5% by mass (4.5

Embodiment 6

[0080] Example 6 is the experimental data when the approximate intermediate value (Ag=3.0, Cu=0.5, Bi=3.0, Ni=0.1) is selected for any addition amount. In the above case, the thermal fatigue test, wettability test and shear test Good results were obtained in both.

Embodiment 7

[0081] Example 7 is experimental data when only Cu in Example 6 was changed to 0.7. In the above case, substantially the same results as in Example 6 were obtained. Therefore, it was 1400 times in the thermal fatigue test, 0.25 in the wetness test, and 4.1 in the shear test.

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Abstract

A lead-free solder, characterized in that it comprises: Ag: 1.2-4.5 mass %, Cu: 0.25-0.75 mass %, Bi: 1-5.8 mass %, Ni: 0.01-0.15 mass %, and remainder Sn . By setting this amount of addition, in addition to the thermal fatigue properties, general solder properties such as wettability and shear strength properties can be further improved.

Description

technical field [0001] The present invention relates to a lead-free solder suitable for use in semiconductor packages such as CSPs, particularly wafer-level semiconductor packages (semiconductor chips), lead-free solder balls, solder joints and Semiconductor circuits with solder joints. Background technique [0002] Along with the multifunctionalization and miniaturization of electronic devices such as multifunctional information terminals (smart phones) and mobile phones, there is a tendency for electronic components mounted in these electronic devices to be miniaturized (ultraminiaturized). [0003] For example, in semiconductor packages such as CSP (Chip Size Package), miniaturization is also advancing, and a wafer-level semiconductor package WL-CSP (Wafer Level-CSP) has appeared. figure 1 It is a cross-sectional view of a main part of a CSP type semiconductor package (CSP package), figure 2 A cross-sectional view of an essential part of a chip-sized WL-CSP semiconduct...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K35/26C22C13/00C22C13/02H01L21/60
CPCC22C13/00C22C13/02H01L2224/48091H01L2924/15311H01L23/49816H01L24/13H01L2224/13113H01L2224/13139H01L2224/16238H01L2224/48229H01L23/49866H01L2224/45144B23K2101/40B23K35/0244B23K35/262H01L2924/00014H01L2924/014H01L2924/01028H01L2924/01029H01L2924/0105H01L2924/01083H01L2924/01047H01L2924/01015H01L2924/01032H01L2924/00
Inventor 立花贤永澤佑也
Owner SENJU METAL IND CO LTD