Low silver hypoeutectic Sn-Cu-Ag lead-free solder for electronic micro connection

A lead-free solder and hypoeutectic technology, applied in the direction of welding/cutting media/materials, welding media, welding equipment, etc., can solve the problem of insufficient process performance, oxidation resistance, wettability, and formability of diffuse solder joints , wettability, diffuseness, poor solder joint formation, high price, etc., to achieve excellent oxidation resistance, low cost, and improve the effect of solder joint formation
CN101214591AInactive Publication Date: 2008-07-09重庆工学院
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
重庆工学院
Publication Date
2008-07-09
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention provides a low-Ag hypo eutectic Sn-Cu-Ag lead-free solder the components of which are 0.5 to 0.65wt percent of Cu, 0.1 to 0.45wt percent of Ag, 0.001 to 0.1wt percent of Ni, 0.001 to 0.3wt percent of Sb, 0.001 to 0.2wt percent of Bi and / or In, 0 to 0.01wt percent of P, 0 to 0.03wt percent of Ge and the rest is Sn. The solder is further characterized in that (1) the content of Ag in the solder of Cu plus Ag is less than 1wt percent is not more than 0.45wt percent; (2) the gross of the microelements like Ni, Sb, Bi, In, P, and Ge, etc., that are added is not more than 0.5wt percent. The solder has the advantages of low cost and excellent oxidation, wettability and overflow resistances, can remarkably reduce the waste of the solder, improve the forming of the welding point, remarkably reduce the connecting defects of braze welding. The solder can replace a Sn-Cu-Ag hypo eutectic material and is suitable for the wave crest welding, dip soldering as well as manual welding and reflow soldering for electric products.
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Description

technical field

[0001] The invention relates to a lead-free solder used in the micro-connection of electronic products in the field of electronic materials. Background technique

[0002] Micro-connection is mainly used in the connection and assembly of electronic products. It is characterized by the small and fine size of the connected objects. Therefore, dissolution, diffusion, surface tension, and strain, which can be ignored in traditional welding techniques, have become important influencing factors. For a long time, tin-based solders containing Pb have been mainly used in electronic micro-connections. Due to the environmental pollution of traditional lead-containing solders, since the 1990s, the world has set off a wave of greening electronic solders. In recent years, the micro-connection of electronic products is gradually promoting the use of lead-free solder, the most respected of which is Sn-Ag-Cu eutectic solder.

[0003] The composition of Sn-Ag-Cu eutectic sold...

Claims

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