A low-temperature composite solder alloy solder sheet and its preparation method and use method

A technology of alloy soldering sheet and composite welding, which is applied to the composition of composite soldering sheet and low-temperature composite soldering alloy soldering sheet to form solder joints, can solve the problems of poor mechanical properties, high cost, low melting point, etc., so as to improve the resistance to thermal load. The ability to improve the dynamic drop load ability, the effect of improving the shear strength
CN112440029BActive Publication Date: 2022-06-17云南锡业集团(控股)有限责任公司研发中心
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
云南锡业集团(控股)有限责任公司研发中心
Publication Date
2022-06-17

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Abstract

The invention provides a low-temperature composite solder alloy solder sheet, which includes a high-temperature layer and a low-temperature layer, and more than one low-temperature layer is respectively arranged on both sides of the high-temperature layer, wherein the solidus temperature of the high-temperature layer is 175-260°C, and the temperature of the low-temperature layer is The solidus temperature is 60~160°C; during the formation of solder joints by the solder sheet of the present invention, the reflow peak temperature is not greater than 220°C, which meets the low temperature reflow requirements; the material composition of the solder sheet does not completely use the eutectic tin-bismuth solder sheet, so that the solder During the service process, the supply of bismuth can be reduced, a large amount of bismuth can be avoided from gathering on the interface, and a brittle phase of continuous bismuth layer can be formed, which improves the ability of solder joints to resist thermal load and dynamic drop load.
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Description

technical field

[0001] The invention relates to the composition of a low-temperature composite solder alloy solder sheet and a method for forming a solder joint, and more particularly to a composite solder sheet for replacing low-temperature tin-bismuth solder sheet welding, which is mainly used in the field of micro-connection. Background technique

[0002] Recent studies have shown that the miniaturization and increased packaging complexity of portable electronic products are making flip chips thinner and thinner, and the packaging process requires multiple steps to complete. Most ultra-thin microprocessors using standard SAC305 alloys cause severe dynamic warpage on the package substrate and PCB. Such defects can be mitigated and SMT yields improved when using a low-temperature soldering process with sub-200°C reflow; in addition, lower reflow temperatures enable the use of cheaper substrates, significantly reducing energy, material, and operating costs. According to the...

Claims

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