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

Active 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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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In view of the current single low-temperature alloys that are easy to gather bismuth at the interface, form a brittle phase of continuous bismuth, have too low melting point, poor mechanical properties, and high cost, and the welding sheet of the composite structure does not involve the field of low-temperature welding

Method used

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

Examples

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Effect test

Embodiment 1

[0039] Example 1: The low-temperature composite solder alloy solder sheet includes a 24.51% high-temperature layer and a 75.49% low-temperature layer. A layer of low-temperature layers is arranged on both sides of the high-temperature layer. The high-temperature layer soldering material is Sn-0.7Cu alloy. The solidus temperature is 229.3℃, the low temperature layer welding material is Sn-52In eutectic alloy, and the solidus temperature is 120.5℃;

[0040] The preparation of the above-mentioned low temperature composite solder alloy pads is as follows ( figure 1 ): Sn-0.7Cu alloy and Sn-52In eutectic alloy were pre-rolled into solder pieces with thickness of 0.25mm and 0.5mm respectively, cut out the size of the target, and cleaned by alcohol ultrasonic cleaning, dilute hydrochloric acid cleaning, alcohol ultrasonic cleaning, After drying; place a low temperature layer on both sides of the high temperature layer to form a sandwich structure, and put it into the rolling mill fo...

Embodiment 2

[0043]Example 2: The low-temperature composite solder alloy solder sheet includes a 47.72% high-temperature layer and a 52.28% low-temperature layer. A layer of low-temperature layers is set on both sides of the high-temperature layer. The high-temperature layer welding material is Sn-0.7Cu alloy. The solidus temperature is 229.3℃, the low temperature layer welding material is Sn-52In eutectic alloy, and the solidus temperature is 120.5℃;

[0044] The preparation of the above-mentioned low-temperature composite solder alloy solder tabs is as follows: respectively pre-rolling Sn-0.7Cu alloy and Sn-52In eutectic alloy into solder tabs with thicknesses of 1.00mm and 0.25mm, cutting out the size of the target, and ultrasonically cleaning with alcohol , after cleaning with dilute hydrochloric acid, ultrasonic cleaning with alcohol, and drying; place a low-temperature layer on both sides of the high-temperature layer to form a sandwich structure, and put it into the rolling mill for ...

Embodiment 3

[0047] Embodiment 3: The low-temperature composite solder alloy solder sheet includes a 60.1% high-temperature layer and a 39.9% low-temperature layer, and a layer of low-temperature layers is arranged on both sides of the high-temperature layer, wherein the high-temperature layer soldering material is Sn-0.7Cu alloy, and the solidus temperature is 229.3℃, the low temperature layer welding material is Sn-52In eutectic alloy, and the solidus temperature is 120.5℃;

[0048] The preparation of the above-mentioned low-temperature composite solder alloy solder pieces is as follows: respectively pre-rolling Sn-0.7Cu alloy and Sn-52In eutectic alloy into solder pieces with thicknesses of 1.00mm and 0.10mm, cutting out the size of the target, and ultrasonically cleaning with alcohol , after cleaning with dilute hydrochloric acid, ultrasonic cleaning with alcohol, and drying; place a low-temperature layer on both sides of the high-temperature layer to form a sandwich structure, and put ...

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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.

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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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K35/26B23K35/18B23K35/40B23K1/00
CPCB23K35/262B23K35/0238B23K35/40B23K1/00
Inventor 彭巨擘蔡珊珊罗晓斌王加俊
Owner 云南锡业集团(控股)有限责任公司研发中心
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