Electronic packaging-used tin-copper high-temperature lead-free pre-formed solder with copper core structure

A preformed, copper core technology, applied in the field of tin-copper high-temperature lead-free preformed solder, tin-copper preformed solder, can solve the problems of limited diffusion layer thickness, complex process, high brittleness, etc., to reduce flux spatter, simplify Welding process, good electrical and thermal conductivity

Inactive Publication Date: 2019-07-05
BEIJING COMPO ADVANCED TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chinese patent CN202240181U discloses a three-layer metal composite soldering sheet. This utility model is composed of three-layer metal structure. Tin alloy sheet, the three-layer metal sheet is welded together. This composite solder sheet is mainly used to replace the crimping connection method used by the microelectronic components of the semiconductor chip and the lead end, but because the upper and lower layers are silver-copper-tin alloy, it greatly inhibits Diffusion of elements during the welding process leads to a limited thickness of the diffusion layer, and the use of silver sheets as the main material leads to high costs and limits its application
Chinese patent CN105252173A discloses a method for preparing solder preforms with a uniform coating. The invention ensures that the upper and lower surfaces of the solder preforms are coated with flux by means of dip coating, and at the same time removes excess flux with a scraper to ensure coating The uniformity of the coating layer, and then the pressure wheel controlled by the air pressure controls the thickness of the coating to reach the required thickness, and at the same time eliminates the air bubbles inside the flux during the dip coating process, thereby ensuring the adhesion of the solder pad coating, and long-term storage coating The layer does not fall off, the process is complicated
Chines

Method used

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  • Electronic packaging-used tin-copper high-temperature lead-free pre-formed solder with copper core structure
  • Electronic packaging-used tin-copper high-temperature lead-free pre-formed solder with copper core structure
  • Electronic packaging-used tin-copper high-temperature lead-free pre-formed solder with copper core structure

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0041] Example 1

[0042] Pre-tinned and flux-coated copper core structures Tin-copper preformed solder structures such as figure 2 As shown, 1 and 5 pre-coating the pre-coating flux coating on the upper and lower surfaces of the tin-plated layer, 3. the center layer of the red copper foil, 2, 4. The pre-coating tin-plating layer above and below the center layer.

[0043] First, prepare 1.28mm×0.1mm (width×thickness) and surface roughness≤Ra0.8 copper foil strip, carry out cleaning pretreatment before plating, use electroplating method to tin copper foil strip, and control the Sn coating of copper foil strip through process control The thickness is 3.5 μm, and then flux (IPA (indole propionic acid) 80wt%, hydrogenated rosin 10wt%, adipic acid 8wt%, OP-10 (polyoxyethylene octylphenol ether-10) 2wt% by dip coating ) on the surface of the tin-plated layer. After the flux is formed into a film, the drying process is placed in a drying room to control the temperature of the dryin...

Example Embodiment

[0044] Example 2

[0045] First, prepare 4.5mm×0.24mm (width×thickness) copper foil tape, carry out cleaning pretreatment before plating, use chemical plating method to tin the copper foil tape, and control the thickness of Sn coating of the copper foil tape to 5μm through the process, and then spray the copper foil with tin. Apply the flux (IPA40wt%, anhydrous ethanol 40wt%, hydrogenated rosin 8wt%, succinic acid 4wt%, adipic acid 6wt%, Tween 2wt%) on the surface of the tin-plated layer, and the flux drying process after film formation Put it in a drying room to control the temperature of the drying room environment at 65°C and the humidity at 20% to form a uniform and stable flux coating with a thickness of 15±3μm. Required size (a×b×c), such as Figure 4 As shown, the solder is preformed in a circular spacer shape and vacuum packed.

Example Embodiment

[0046] Example 3

[0047] First, prepare 4.2mm×0.036mm (width×thickness) and surface roughness≤Ra0.8 copper foil strip, carry out pre-plating cleaning and pretreatment, use electroplating method to tin plate copper foil strip, and control the Sn coating of copper foil strip through process control The thickness is 5 μm, and then the flux (ethyl acetate 38wt%, butanone 43wt%, polymerized rosin 7wt%, glutaric acid 9wt%, fluorosurfactant FC-4430 3wt%) is coated on the surface of the tin plating layer by spraying , the flux film forming process is placed in a drying room with a temperature of 40 ° C and a humidity of 28% to form a uniform and stable flux coating thickness of 20 ± 2.5 μm. Finally, the prepared copper core structure foil is punched through the mold. , make the required size (a×c), such as Figure 5 As shown, a disc is preformed with copper core structure solder and vacuum packaged.

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Abstract

The invention relates to tin-copper high-temperature lead-free pre-formed solder with a copper core structure as well as a preparation method and application thereof, and belongs to the technical field of high-temperature soft solder. The solder comprises a purple copper foil sheet, wherein an upper tin-plated layer and a lower tin-plated layer are arranged on the upper surface and the lower surface of the purple copper foil sheet respectively; or the solder comprises a purple copper foil sheet, the upper tin-plated layer and the lower tin-plated layer are arranged on the upper surface and thelower surface of the purple copper foil sheet respectively, and an upper soldering flux layer and a lower soldering flux layer are arranged on the outer surface of the upper tin-plated layer and theouter surface of the lower tin-plated layer respectively. The tin-copper pre-formed solder with the copper core structure has the shape diversity same as a common pre-formed soldering piece, meanwhile, the ultra-thin, ultra-precision pre-formed solder structure meeting the application requirement of high-precision packaging can be prepared, the solder is suitable for the miniaturized personalizedrequirements of electronic elements, and except that the advantage of small-tolerance precise usage is realized, soldering flux is pre-coated to simplify the soldering process to reduce the splashingof the soldering flux; the electricity conducting and heat conduction performance of an assembly is improved while the bonding strength is ensured, the hardness of a soldered part is reduced, the brittleness of the soldered part is reduced, and the application of the high-performance high-temperature lead-free solder is realized in a true sense.

Description

technical field [0001] The invention relates to a tin-copper preformed solder with a copper core structure, in particular to a tin-copper high-temperature lead-free preformed solder with a copper core structure for electronic packaging, and the preparation method and application of the solder, belonging to the high-temperature solder technology field. Background technique [0002] Solder is a metal alloy material that fills the weld during welding. Solder bars, solder wires, solder balls, solder paste, etc. have been widely used in the PCB manufacturing process. However, with the development of electronic assembly technology, electronic components are becoming more and more With the development of miniaturization and individualization, and the development of electronics towards ultra-high power and ultra-high integration, the requirements for soldering materials are becoming more and more special. The existing solder bars, solder wires, solder balls, solder paste, etc. canno...

Claims

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Application Information

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IPC IPC(8): B23K35/14
CPCB23K35/0238
Inventor 贺会军刘英杰张富文刘希学朱学新赵朝辉胡强王志刚安宁徐蕾刘建卢彩涛朱捷林刚
Owner BEIJING COMPO ADVANCED TECH
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