CN117548896A - Anti-collapse composite soldering paste reinforced by coated metal particles, and preparation method and application thereof - Google Patents
Anti-collapse composite soldering paste reinforced by coated metal particles, and preparation method and application thereof Download PDFInfo
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- CN117548896A CN117548896A CN202311354920.9A CN202311354920A CN117548896A CN 117548896 A CN117548896 A CN 117548896A CN 202311354920 A CN202311354920 A CN 202311354920A CN 117548896 A CN117548896 A CN 117548896A
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- 238000005476 soldering Methods 0.000 title claims abstract description 185
- 239000002131 composite material Substances 0.000 title claims abstract description 120
- 239000002923 metal particle Substances 0.000 title claims abstract description 65
- 238000002360 preparation method Methods 0.000 title abstract description 33
- 230000004907 flux Effects 0.000 claims abstract description 52
- 229910052802 copper Inorganic materials 0.000 claims abstract description 21
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000011258 core-shell material Substances 0.000 claims abstract description 6
- 229910000679 solder Inorganic materials 0.000 claims description 73
- 239000000843 powder Substances 0.000 claims description 43
- 239000002184 metal Substances 0.000 claims description 28
- 229910052751 metal Inorganic materials 0.000 claims description 28
- 238000003756 stirring Methods 0.000 claims description 25
- 229910045601 alloy Inorganic materials 0.000 claims description 18
- 239000000956 alloy Substances 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 14
- 229910052709 silver Inorganic materials 0.000 claims description 9
- 229910017944 Ag—Cu Inorganic materials 0.000 claims description 8
- 238000004377 microelectronic Methods 0.000 claims description 8
- 229910020830 Sn-Bi Inorganic materials 0.000 claims description 7
- 229910018728 Sn—Bi Inorganic materials 0.000 claims description 7
- 238000004806 packaging method and process Methods 0.000 claims description 7
- RSWGJHLUYNHPMX-UHFFFAOYSA-N Abietic-Saeure Natural products C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 claims description 5
- KHPCPRHQVVSZAH-HUOMCSJISA-N Rosin Natural products O(C/C=C/c1ccccc1)[C@H]1[C@H](O)[C@@H](O)[C@@H](O)[C@@H](CO)O1 KHPCPRHQVVSZAH-HUOMCSJISA-N 0.000 claims description 5
- KHPCPRHQVVSZAH-UHFFFAOYSA-N trans-cinnamyl beta-D-glucopyranoside Natural products OC1C(O)C(O)C(CO)OC1OCC=CC1=CC=CC=C1 KHPCPRHQVVSZAH-UHFFFAOYSA-N 0.000 claims description 5
- 229910006404 SnO 2 Inorganic materials 0.000 claims description 2
- 238000003466 welding Methods 0.000 abstract description 20
- 239000000463 material Substances 0.000 abstract 1
- 239000002245 particle Substances 0.000 description 60
- 238000012360 testing method Methods 0.000 description 19
- 230000000052 comparative effect Effects 0.000 description 17
- 239000007788 liquid Substances 0.000 description 10
- 229910020816 Sn Pb Inorganic materials 0.000 description 7
- 229910020922 Sn-Pb Inorganic materials 0.000 description 7
- 229910008783 Sn—Pb Inorganic materials 0.000 description 7
- 229910000765 intermetallic Inorganic materials 0.000 description 6
- 239000000523 sample Substances 0.000 description 6
- 238000004100 electronic packaging Methods 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
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- 238000011161 development Methods 0.000 description 4
- 239000010410 layer Substances 0.000 description 4
- 229910052759 nickel Inorganic materials 0.000 description 4
- 229910017482 Cu 6 Sn 5 Inorganic materials 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 3
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- 238000009736 wetting Methods 0.000 description 3
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical group CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- 229910007116 SnPb Inorganic materials 0.000 description 2
- 239000013543 active substance Substances 0.000 description 2
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- 238000007254 oxidation reaction Methods 0.000 description 2
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- 239000002904 solvent Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- 238000012876 topography Methods 0.000 description 2
- DUIOKRXOKLLURE-UHFFFAOYSA-N 2-octylphenol Chemical group CCCCCCCCC1=CC=CC=C1O DUIOKRXOKLLURE-UHFFFAOYSA-N 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910018471 Cu6Sn5 Inorganic materials 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 235000021355 Stearic acid Nutrition 0.000 description 1
- GSEJCLTVZPLZKY-UHFFFAOYSA-N Triethanolamine Chemical group OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
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- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical group CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 1
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229940051841 polyoxyethylene ether Drugs 0.000 description 1
- 229920000056 polyoxyethylene ether Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400 degrees C
- B23K35/262—Sn as the principal constituent
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
- B23K35/0222—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in soldering, brazing
- B23K35/0244—Powders, particles or spheres; Preforms made therefrom
- B23K35/025—Pastes, creams, slurries
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/36—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
- B23K35/362—Selection of compositions of fluxes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
Abstract
The invention provides a coated metal particle reinforced collapse-resistant composite soldering paste, a preparation method and application thereof. Wherein, the mass fraction of the coated metal particles is 5-60%, the mass fraction of the soldering flux is 8-12%, and the rest is soldering tin powder; the coated metal particles have a core-shell structure, the core is made of Cu and Al materials, a skeleton support is formed in the welding spot, the collapse resistance of the welding spot is enhanced, the collapse resistance and the electric conduction and heat conduction properties of the composite soldering paste are obviously improved, and meanwhile, the cost is reduced.
Description
Technical Field
The invention relates to the technical field of welding, in particular to a collapse-resistant composite soldering paste reinforced by coated metal particles, and a preparation method and application thereof.
Background
The current trend of electronic products is toward green environmental protection, and toward miniaturization, high performance, high reliability, high security and electromagnetic compatibility. The electronic packaging technology also rapidly develops to the high integration and high performance, the number of welding spots on a unit area is increased, the size is reduced, the distance between adjacent welding spots is further reduced, and the electronic packaging technology has higher requirements on the collapse resistance of the electronic solder and prevents the device from failure caused by bridging of the welding spots. Meanwhile, the electronic solder plays roles of force, heat and electricity in the use process, and particularly, the electronic solder is widely applied to high-power devices such as IGBT and the like, and the welding spots are required to have higher electric conductivity and heat conductivity.
The collapse resistance and the electric conduction and heat conduction properties of the traditional SnPb solder and SnAgCu, snBi and other lead-free solders can not meet the requirements of the development of the electronic packaging technology gradually, and the collapse resistance and the electric conduction and heat conduction properties of the traditional SnPb solder are improved on the basis of keeping the excellent properties of the solders, so that the lead-free solder has important significance for the development of the microelectronics industry.
Disclosure of Invention
In order to overcome the defects in the prior art, the main purpose of the invention is to provide the coated metal particle reinforced collapse resistant composite soldering paste, and the preparation method and the application thereof. Wherein, the mass fraction of the coated metal particles is 5-60%, the mass fraction of the soldering flux is 8-12%, and the rest is soldering tin powder; the coated metal particles have a core-shell structure, the Cu and Al cores mainly play a supporting role, skeleton supports are formed in welding spots, collapse resistance of the welding spots is enhanced, collapse resistance of the composite soldering paste is remarkably improved, and meanwhile cost is reduced.
In order to achieve the above object, according to a first aspect of the present invention, there is provided a collapse resistant composite solder paste reinforced with coated metal particles.
The collapse resistant composite solder paste reinforced by the coated metal particles comprises the following components in percentage by mass:
5-60% of coated metal particles, 8-12% of soldering flux and the balance of soldering tin powder;
wherein the coated metal particles are of a core-shell structure, the core comprises but not limited to Cu, al metal, pb-based alloy and Cu-based alloy, and the shell comprises but not limited to Ag, ni metal, pbO and SnO 2 、Ag 2 O。
Further, the collapse resistant composite solder paste comprises the following components in percentage by mass:
20-60% of coated metal particles, 9-11% of soldering flux and the balance of soldering tin powder.
Further, the core of the coated metal particles is Cu and Al metal.
Further, the shell layers of the coated metal particles are Ag and Ni metals.
Further, the soldering tin powder is one of Sn-Bi series alloy powder, sn-Ag-Cu series alloy powder and Sn-Pb series alloy powder.
Further, the soldering flux is rosin type soldering flux.
In order to achieve the above object, according to a second aspect of the present invention, there is provided a method of preparing a collapse resistant composite solder paste reinforced with coated metal particles.
The preparation method of the collapse resistant composite soldering paste reinforced by the coated metal particles comprises the following steps:
1) Adding the coated metal particles into the soldering flux, and fully and uniformly stirring to obtain a coated metal particle-soldering flux system;
2) And adding soldering tin powder into the metal-coated particle-soldering flux system, and fully stirring to obtain the collapse-resistant composite soldering paste.
Further, in the step 1), the stirring rate is 60 to 100 rpm, and the stirring time is 10 to 30 minutes.
In step 2), the stirring rate is 80-120 rpm, and the stirring time is 15-30 minutes.
In order to achieve the above object, according to a third aspect of the present invention, there is provided the use of a coated metal particle-reinforced collapse resistant composite solder paste.
The collapse-resistant composite soldering paste is applied to the fields of microelectronic packaging and photovoltaics.
The coated metal particles in the coated metal particle reinforced collapse-resistant composite soldering paste disclosed by the invention have a core-shell structure, cu and Al cores mainly play a supporting role, framework supports are formed in the soldering points, and the collapse resistance and the electric conduction and heat conduction properties of the soldering points are enhanced; ag. The Ni shell layer can solve Cu 6 Sn 5 Excessive growth of intermetallic compound and oxide Al on surface of Al particles 2 O 3 And the Sn liquid is difficult to wet.
The collapse resistance and the electric and heat conductivity of the composite soldering paste are obviously improved, and the cost is obviously reduced.
The invention has the advantages that:
1. the collapse-resistant composite soldering paste has the advantages of uncomplicated self components, simple preparation process, suitability for welding various substrates and components, good collapse resistance of soldering spots, excellent electric and heat conductivity and high reliability of soldering spots.
2. The collapse-resistant composite soldering paste not only meets the fields of microelectronic packaging and photovoltaics, but also is particularly suitable for packaging high-power devices such as IGBT.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:
FIG. 1 is a surface topography of Cu@Ag particles in an example provided by the invention;
FIG. 2 is a cross-sectional morphology of Cu@Ag particles in an embodiment provided by the invention;
FIG. 3 is a surface topography of Al@Ni particles in an example provided by the present invention;
FIG. 4 is a cross-sectional morphology of Al@Ni particles in an example provided by the present invention;
FIG. 5 is a schematic illustration of the dimensions of a printed steel mesh in a slump test;
FIG. 6 is a slump test result of the composite solder paste of example 5 provided in the present invention;
FIG. 7 is a slump test result of the composite solder paste of example 9 according to the present invention;
FIG. 8 is a slump test result of the composite solder paste of example 14 provided by the present invention;
fig. 9 is a slump test result of the solder paste of comparative example 1 provided in the present invention;
fig. 10 is a slump test result of the solder paste of comparative example 2 provided in the present invention;
fig. 11 is a slump test result of the solder paste of comparative example 3 provided by the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
Cu and Al particles have the advantages of excellent electric conduction and heat conduction properties, easiness in processing, low cost and the like, and are commonly used as reinforcing phases for preparing composite soldering paste so as to improve the mechanical properties, electric conduction and heat conduction properties and the like of the soldering paste. However, the Cu and Al particle reinforced composite solder paste still has a certain problem in terms of reliability, which limits its application in the microelectronics field.
At the welding temperature, the reaction rate of Cu particles and Sn liquid is too high, and a large amount of Cu is generated 6 Sn 5 Intermetallic compounds grow into a rod shape in a specific orientation. On the one hand, cu with high thermal resistance and high electric resistance 6 Sn 5 Intermetallic compounds are generated on the surface layers of Cu particles, so that the advantages of high electric conductivity and heat conductivity of the Cu particles are not exerted, and the electric conductivity and heat conductivity of the composite soldering paste are difficult to further improve. On the other hand, rod-like Cu 6 Sn 5 The brittleness of the intermetallic compound is obvious, and under the action of load, cracks are easy to cause along Cu 6 Sn 5 Phase expansion causes brittle fracture of the welding spot, and reduces the reliability of the welding spot.
The problem of Al particles as a reinforcing phase of composite solder paste is mainly manifested in the wetting problem with Sn liquid. Al is used as the easily oxidized metal, and a layer of compact Al is generated on the particle surface 2 O 3 Due to Al 2 O 3 The bonding capability of the interface between Al particles and the matrix is poor due to the fact that the bonding capability is difficult to wet with Sn liquid, and therefore the reliability of welding spots is reduced.
Under the background of high integration and high performance development of electronic packaging technology, the number of welding spots on a unit area is increased, the size is reduced, the distance between adjacent welding spots is further reduced, and the electronic packaging technology has higher requirements on collapse resistance of electronic solder and prevents device failure caused by bridging of welding spots. The collapse resistance of the existing solder cannot meet the development requirement of highly integrated packaging, and the collapse resistance of the solder needs to be further improved.
In order to solve the problem that the conventional Sn-Bi soldering paste, sn-Ag-Cu soldering paste and Sn-Pb soldering paste are poor in collapse resistance, the collapse resistance of the composite soldering paste is remarkably improved, and the first aspect of the invention provides the collapse-resistant composite soldering paste reinforced by coated metal particles.
The collapse-resistant composite soldering paste comprises the following components in percentage by mass:
5 to 60 percent of coated metal particles;
8-12% of soldering flux;
the balance being soldering tin powder.
Wherein, the coated metal particles are of a core-shell structure, the core comprises but not limited to Cu and Al metals, and the shell comprises but not limited to Ag and Ni metals.
In the invention, the collapse-resistant composite soldering paste melts soldering tin powder in the welding process, the melting point of the coated metal particles is higher, the coated metal particles do not melt at the welding temperature, a large number of metal cores in the molten Sn liquid are mutually stacked to form a framework support, and meanwhile, part of molten Sn liquid is adsorbed by utilizing capillary action among the coated metal particles to prevent the expansion of the molten Sn liquid, so that the collapse-resistant capability of the soldering paste is remarkably improved.
Fig. 1 and 2 show surface and cross-sectional morphology diagrams of cu@ag particles, respectively, in an embodiment of the invention.
Fig. 3 and 4 show surface and cross-sectional morphology diagrams of al@ni particles, respectively, in an embodiment of the invention.
As can be seen from fig. 1 to 4, both cu@ag and al@ni particles have a good sphericity and a good particle size distribution range, so that the collapse-resistant composite solder paste is ensured to have good printing performance.
In some embodiments of the invention, the coated metal particles are 20-60% by mass, the flux is 9-11% by mass, and the remainder is solder powder.
Exemplary, the mass percent of the coated metal particles is any of 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60% or any value satisfying the above ranges.
Illustratively, the flux is any of 9%, 10%, 11% by mass or any value satisfying the above range of values.
As some embodiments of the present invention, the coated metal particles have a particle size in the range of 2 to 38 μm.
Exemplary coated metal particles have a particle size of any one of 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm or any value satisfying the above range values.
As some embodiments of the present invention, the core of the coated metal particles may be metallic Cu, metallic Al, pb-based alloys, cu-based alloys, and the like.
As some embodiments of the invention, the shell layer of the coated metal particles can be metal Ag, metal Ni, pbO, snO 2 、Ag 2 O, etc.
In certain embodiments of the present invention, the coated metal particles may be Cu@Ag, cu@Ni, al@Ag, al@Ni metal spherical powders.
In the embodiment of the invention, the soldering tin powder is one of Sn-Bi series alloy powder, sn-Ag-Cu series alloy powder and Sn-Pb series alloy powder.
Among them, sn-Bi series alloy powders include, but are not limited to, sn58Bi powders.
The Sn-Ag-Cu series alloy powders include, but are not limited to, sn3Ag0.5Cu powder.
The Sn-Pb series alloy powder includes, but is not limited to, sn37Pb powder.
In an embodiment of the present invention, the flux is a rosin flux.
Wherein the rosin type soldering flux consists of 16% of active agent, 37% of film forming agent, 2% of regulator, 1.5% of surfactant and the balance of solvent according to mass percent.
In an embodiment of the invention, the active agent is stearic acid; the film forming agent consists of rosin and polyethylene glycol according to the mass fraction of 5:1, wherein the regulator is triethanolamine, the surfactant is octyl phenol polyoxyethylene ether, and the solvent is isopropanol.
It is worth mentioning that the collapse-resistant composite soldering paste also has excellent electric and heat conduction properties, and the Ag and Ni coated on the surface layer of the metal particles have alloying action with molten Sn liquid, so that direct contact between Cu and Sn liquid is avoided, and high-thermal resistance and high-resistance Cu are reduced 6 Sn 5 The formation of intermetallic compound solves the problem of difficult wetting of Al particles caused by oxidation, ensures excellent electric and heat conduction performance of Cu and Al metal cores, and greatly improves the overall electric and heat conduction performance of the composite soldering paste because a large number of metal cores form electric and heat conduction paths between each other.
In order to solve the problem of poor collapse resistance of the conventional Sn-Bi soldering paste, sn-Ag-Cu soldering paste and Sn-Pb soldering paste, the collapse resistance of the composite soldering paste is remarkably improved, and the second aspect of the invention provides a preparation method of the collapse-resistant composite soldering paste reinforced by coated metal particles.
The composite solder paste with reinforced coated metal particles is the composite solder paste provided by the first aspect of the invention.
The preparation method of the collapse resistant composite solder paste reinforced by the coated metal particles comprises the following steps.
Step 1): a coated metal particle-flux system is prepared.
Firstly, weighing coated metal particles, soldering flux and soldering tin powder according to the required mass percentage, then adding the coated metal particles into the soldering flux for mechanical stirring, and stirring for 10-30 minutes by a stirrer at the rotating speed of 60-100 rpm to obtain a uniformly mixed coated metal particle-soldering flux system.
Step 2): preparing the collapse resistant composite solder paste reinforced by the coated metal particles.
And adding the soldering powder into the uniformly mixed coated metal particle-scaling powder system, and mechanically stirring again at the stirring speed of 80-120 r/min for 15-30 min to obtain the final coated metal particle reinforced collapse-resistant composite soldering paste.
In order to solve the problem of poor collapse resistance of the conventional Sn-Bi soldering paste, sn-Ag-Cu soldering paste and Sn-Pb soldering paste, the collapse resistance of the composite soldering paste is remarkably improved, and the third aspect of the invention provides application of the collapse-resistant composite soldering paste reinforced by coated metal particles in microelectronic packaging.
The composite soldering paste with reinforced coated metal particles is the composite soldering paste provided by the first aspect of the invention or the composite soldering paste prepared by the method provided by the second aspect of the invention.
It should be noted that the microelectronics are conventional components in the art, and the like.
In order to solve the problem of poor collapse resistance of the conventional Sn-Bi soldering paste, sn-Ag-Cu soldering paste and Sn-Pb soldering paste, the collapse resistance of the composite soldering paste is remarkably improved, and the fourth aspect of the invention provides application of the collapse-resistant composite soldering paste reinforced by coated metal particles in the photovoltaic field.
The composite soldering paste with reinforced coated metal particles is the composite soldering paste provided by the first aspect of the invention or the composite soldering paste prepared by the method provided by the second aspect of the invention.
The coated metal particle-reinforced collapse resistant composite solder paste of the present invention and the method of preparing the same will be described in further detail below by way of examples and comparative examples.
It should be noted that the scope of the present invention is not limited to the embodiments described in the examples.
Example 1
The preparation method of the Sn58Bi composite soldering paste added with Cu@Ag particles with the mass fraction of 60 percent comprises the following steps:
(1) The Cu@Ag particles, the soldering flux and the Sn58Bi soldering powder are weighed according to the mass percentage of 60:8:32.
(2) And (3) adding Cu@Ag particles into the soldering flux for mechanical stirring, and stirring for 30 minutes by a stirrer at a rotating speed of 100 revolutions per minute to obtain a uniform Cu@Ag particle-soldering flux system.
(3) Adding the Sn58Bi soldering tin powder with the specified mass into the uniformly mixed Cu@Ag particle-scaling powder system, and mechanically stirring again, wherein the stirring speed is 80 revolutions per minute, and the stirring time is 15 minutes, so as to obtain the Cu@Ag particle reinforced collapse-resistant composite soldering paste with the mass fraction of 60%.
Example 2
A Sn58Bi composite soldering paste added with Cu@Ni particles with the mass fraction of 40%.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of Cu@Ni particles, soldering flux and Sn58Bi soldering powder are 40:10:50.
Example 3
A Sn58Bi composite soldering paste added with 30% of Al@Ni particles by mass fraction.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of the Al@Ni particles, the soldering flux and the Sn58Bi soldering powder are 30:10:60.
Example 4
A Sn58Bi composite soldering paste added with 20% of Al@Ag particles by mass fraction.
Wherein, the mass percentages of Al@Ag particles, soldering flux and Sn58Bi soldering powder are 20:10:70, and the preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the component proportions and the technological parameters are different.
Example 5
A Sn58Bi composite soldering paste added with Cu@Ag particles with the mass fraction of 10%.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of Cu@Ag particles, soldering flux and Sn58Bi soldering powder are 10:12:78.
Example 6
A Sn58Bi composite soldering paste added with 5% of Al@Ni particles by mass fraction.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of the Al@Ni particles, the soldering flux and the Sn58Bi soldering powder are 5:12:83.
Example 7
Sn3Ag0.5Cu composite solder paste added with Cu@Ag particles with mass fraction of 60%.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of Cu@Ag particles, soldering flux and Sn3Ag0.5Cu soldering powder are 60:8:32.
Example 8
Sn3Ag0.5Cu composite solder paste added with Cu@Ni particles with mass fraction of 40%.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of Cu@Ni particles, soldering flux and Sn3Ag0.5Cu soldering powder are 40:10:50.
Example 9
Sn3Ag0.5Cu composite solder paste added with 30% of Al@Ni particles by mass fraction.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of Al@Ni particles, soldering flux and Sn3Ag0.5Cu soldering powder are 30:10:60.
Example 10
Sn3Ag0.5Cu composite solder paste added with 20% of Al@Ag particles by mass fraction.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of Al@Ag particles, soldering flux and Sn3Ag0.5Cu soldering powder are 20:10:70.
Example 11
Sn3Ag0.5Cu composite solder paste added with Cu@Ag particles with mass fraction of 10%.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of Cu@Ag particles, soldering flux and Sn3Ag0.5Cu soldering powder are 10:12:78.
Example 12
Sn3Ag0.5Cu composite solder paste added with 5% of Al@Ni particles by mass fraction.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of Al@Ni particles, soldering flux and Sn3Ag0.5Cu soldering powder are 5:12:83 and the component proportions and the technological parameters are different.
Example 13
A Sn37Pb composite soldering paste added with Cu@Ag particles with mass fraction of 60%.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of Cu@Ag particles, soldering flux and Sn37Pb soldering powder are 60:8:32.
Example 14
A Sn37Pb composite soldering paste added with Cu@Ni particles with the mass fraction of 40%.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of Cu@Ni particles, soldering flux and Sn37Pb soldering powder are 40:10:50.
Example 15
A Sn37Pb composite soldering paste added with 30% of Al@Ni particles by mass fraction.
Wherein, the mass percentages of Al@Ni particles, soldering flux and Sn37Pb soldering powder are 30:10:60, and the preparation method of the composite soldering paste is the same as that of example 1 except for different component proportions and technological parameters.
Example 16
A Sn37Pb composite soldering paste added with 20% of Al@Ag particles by mass fraction.
Wherein, the mass percentages of Al@Ag particles, soldering flux and Sn37Pb soldering powder are 20:10:70, and the preparation method of the composite soldering paste is the same as that of example 1 except for different component proportions and technological parameters.
Example 17
A Sn37Pb composite soldering paste added with Cu@Ag particles with the mass fraction of 10%.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of Cu@Ag particles, soldering flux and Sn37Pb soldering powder are 10:12:78.
Example 18
A Sn37Pb composite soldering paste added with 5% of Al@Ni particles by mass fraction.
The preparation method of the composite soldering paste is the same as that of the embodiment 1 except that the mass percentages of the Al@Ni particles, the soldering flux and the Sn37Pb soldering powder are 5:12:83.
Comparative example 1
The invention discloses Sn58Bi soldering paste, which comprises the following preparation methods:
(1) The Sn58Bi solder powder and flux were weighed at a mass percentage of 88:12.
(2) And adding the Sn58Bi soldering tin powder with the specified proportion into the soldering flux, and mechanically stirring at the stirring speed of 120 rpm for 30 minutes to obtain the Sn58Bi soldering paste.
Comparative example 2
The invention discloses Sn3Ag0.5Cu solder paste, which is prepared by the following steps:
(1) The Sn3Ag0.5Cu solder powder and the soldering flux are weighed according to the mass percentage of 88:12.
(2) And adding Sn3Ag0.5Cu soldering tin powder in a specified proportion into the soldering flux, and mechanically stirring at a stirring speed of 120 rpm for 30 minutes to obtain the Sn3Ag0.5Cu soldering paste.
Comparative example 3
Disclosed is a Sn37Pb soldering paste, the preparation method of which comprises:
(1) The Sn37Pb solder powder and flux were weighed at a mass percentage of 88:12.
(2) And adding the Sn37Pb soldering powder with the specified proportion into the soldering flux, and mechanically stirring at the stirring speed of 120 rpm for 30 minutes to obtain the Sn37Pb soldering paste.
Test experiment
(1) Microstructure tissue observation and analysis are carried out by using a scanning electron microscope device.
The preparation flow of the section observation sample of the coated metal particles is as follows:
firstly, the coated metal particles are added into epoxy resin to be fully and uniformly stirred, then the curing agent with fixed proportion is added, and the mixture is uniformly stirred again. And (3) grinding and polishing the surface until the surface is mirror surface after the sample is solidified, and finally observing under a scanning electron microscope.
The adopted analysis equipment is equipment of a conventional model in the field, and the analysis method meets the corresponding national standard.
(2) And (5) testing collapse performance, and finishing by using a reflow oven.
Firstly, printing soldering paste on a glass sheet through a printing steel screen, wherein the size schematic diagram of the printing steel screen is shown in fig. 5;
then, the glass sheet printed with the soldering paste is reflowed in a reflow oven;
and finally, observing the appearance of the solder paste after reflow by using an optical microscope.
Wherein, the preparation process parameters and performance test results of the compound soldering paste with different components and mass percentages in the examples and the comparative examples are summarized in tables 1-2, and are shown in fig. 4-9.
Table 1 summary of process parameters for the preparation of the composite solder paste in examples and comparative examples
Table 2 collapse test results of composite solder paste of different compositions and ratios in examples and comparative examples
(3) And testing the thermal conductivity of the composite solder paste.
The specific test method of the thermal conductivity comprises the following steps: and (3) placing a certain amount of composite soldering paste into a large-caliber beaker, and reflowing in a reflow oven, wherein the sample is large in size, and the reflow time at the peak temperature is prolonged to 10 minutes so as to ensure that the soldering flux is fully volatilized, and cooling the sample to obtain a solder sheet. And (3) finely polishing and polishing the solder sheet until the solder sheet reaches a mirror surface, finally obtaining a diffusion coefficient test sample with the diameter of 6.0mm and the thickness of 1mm, and obtaining the thermal diffusion coefficient of the composite soldering paste by using a laser flash point method heat conduction analyzer.
In addition, the density and specific heat capacity of the composite solder were measured using an electron densitometer and a differential scanning calorimeter, respectively.
According to the formula: thermal conductivity = diffusion coefficient x density x specific heat capacity, the thermal conductivity of the composite solder paste is calculated. The test results are shown in Table 3.
Table 3 results of thermal conductivity tests for different compositions and mass percentages of composite solder paste in examples and comparative examples
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(4) And testing the conductivity of the composite soldering paste.
The specific test method of the volume resistivity of the composite soldering paste comprises the following steps:
and printing the composite soldering paste with the specified quality on the PCB board with the reserved soldering points, and carrying out reflow soldering to form the soldering points, wherein the PCB board forms a passage. The resistance of the solder joints was measured 5 times with each of the examples and comparative examples using an RTS-8 type four-point probe tester, and the average value of the resistance was recorded to obtain table 4.
Table 4 results of thermal conductivity tests for different compositions and mass percentages of composite solder paste in examples and comparative examples
| Examples | Composite solder paste composition | Resistivity (mu omega m) |
| Example 1 | Sn58Bi+60％Cu@Ag | 0.118 |
| Example 2 | Sn58Bi+40％Cu@Ni | 0.124 |
| Example 3 | Sn58Bi+30％Al@Ni | 0.162 |
| Example 4 | Sn58Bi+20％Al@Ag | 0.186 |
| Example 5 | Sn58Bi+10％Cu@Ag | 0.224 |
| Example 6 | Sn58Bi+5％Al@Ni | 0.247 |
| Example 7 | Sn3Ag0.5Cu+60％Cu@Ag | 0.043 |
| Example 8 | Sn3Ag0.5Cu+40％Cu@Ni | 0.052 |
| Example 9 | Sn3Ag0.5Cu+30％Al@Ni | 0.075 |
| Example 10 | Sn3Ag0.5Cu+20％Al@Ag | 0.084 |
| Example 11 | Sn3Ag0.5Cu+10％Cu@Ag | 0.102 |
| Example 12 | Sn3Ag0.5Cu+5％Al@Ni | 0.110 |
| Example 13 | Sn37Pb+60％Cu@Ag | 0.054 |
| Example 14 | Sn37Pb+40％Cu@Ni | 0.071 |
| Example 15 | Sn37Pb+30％Al@Ni | 0.082 |
| Example 16 | Sn37Pb+20％Al@Ag | 0.094 |
| Example 17 | Sn37Pb+10％Cu@Ag | 0.109 |
| Example 18 | Sn37Pb+5％Al@Ni | 0.113 |
| Comparative example 1 | Sn58Bi | 0.387 |
| Comparative example 2 | Sn3Ag0.5Cu | 0.132 |
| Comparative example 3 | Sn37Pb | 0.135 |
Fig. 6, 7 and 8 are the slump test results of the slump-resistant composite solder paste of examples 5, 9 and 14, respectively.
Fig. 9, 10 and 11 are the slump test results of the solder pastes of comparative examples 1, 2 and 3, respectively.
As can be seen from fig. 6-11 and table 2, the addition of 5-60% of the coated metal particles significantly improves the collapse resistance of Sn58Bi, sn3ag0.5cu, sn37Pb solder paste. When the added mass fraction of the coated metal particles exceeds 20%, the minimum bridging distance of the Sn58Bi, sn3Ag0.5Cu and Sn37Pb composite solder paste is smaller than 0.05mm, which indicates that the composite solder paste still has no bridging under the condition of the minimum test distance of 0.05mm, and has excellent collapse resistance.
The composite soldering paste has the advantages of remarkably improving collapse resistance and simultaneously having excellent electric and heat conductivity. Because Ag, ni and Sn liquid have slower reaction rate and good wettability, the generation of Cu6Sn5 intermetallic compounds on the surfaces of Cu particles can be inhibited, the problem of difficult wetting of Al particles caused by oxidation is solved, the excellent heat and electric conductivity of Cu and Al cores is ensured, and the electric and heat conductivity of collapse-resistant composite soldering paste is further improved.
As can be seen from table 3 and table 4, the addition of 5 to 60% of the coated metal particles can significantly improve the heat conductivity and the electrical conductivity of the Sn58Bi, sn3ag0.5cu, sn37Pb composite solder paste, the thermal conductivity is significantly increased, the resistivity is reduced, and the larger the amount of the coated metal particles is, the larger the electrical conductivity and the thermal conductivity of the composite solder paste is.
In conclusion, the composite soldering paste provided by the invention has the advantages of uncomplicated self components, simple preparation process, good collapse resistance of soldering points, excellent electric conduction and heat conduction properties, high soldering point reliability, suitability for welding various substrates and components, and suitability for the fields of microelectronic packaging and photovoltaics.
It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only, and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "includes," "including," and "having" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless an order of performance is explicitly stated. It should also be appreciated that additional or alternative steps may be used.
The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. The collapse-resistant composite solder paste reinforced by the coated metal particles is characterized by comprising the following components in percentage by mass:
5-60% of coated metal particles, 8-12% of soldering flux and the balance of soldering tin powder;
wherein the coated metal particles are of a core-shell structure, the core comprises but not limited to Cu, al metal, pb-based alloy and Cu-based alloy, and the shell comprises but not limited to Ag, ni metal, pbO and SnO 2 、Ag 2 O。
2. The coated metal particle reinforced collapse resistant composite solder paste of claim 1, wherein the collapse resistant composite solder paste comprises the following components in mass percent:
20-60% of coated metal particles, 9-11% of soldering flux and the balance of soldering tin powder.
3. The coated metal particle reinforced collapse resistant composite solder paste of claim 1, wherein the core of the coated metal particles is Cu, al metal.
4. The coated metal particle-reinforced collapse resistant composite solder paste of claim 1, wherein the shell of the coated metal particles is Ag, ni metal.
5. The coated metal particle reinforced collapse resistant composite solder paste of claim 1, wherein the solder powder is one of Sn-Bi series alloy powder, sn-Ag-Cu series alloy powder, sn-Pb series alloy powder.
6. The coated metal particle reinforced collapse resistant composite solder paste of claim 1, wherein the flux is a rosin flux.
7. A method of preparing a coated metal particle-reinforced collapse resistant composite solder paste according to any one of claims 1 to 6, comprising the steps of:
1) Adding the coated metal particles into the soldering flux, and fully and uniformly stirring to obtain a coated metal particle-soldering flux system;
2) And adding soldering tin powder into the metal-coated particle-soldering flux system, and fully stirring to obtain the collapse-resistant composite soldering paste.
8. The method for preparing a collapse resistant composite solder paste reinforced by coated metal particles according to claim 7, wherein in the step 1), the stirring rate is 60 to 100 rpm and the stirring time is 10 to 30 minutes.
9. The method for preparing a collapse resistant composite solder paste reinforced by coated metal particles according to claim 7, wherein in the step 2), the stirring rate is 80 to 120 rpm, and the stirring time is 15 to 30 minutes.
10. Use of the collapse resistant composite solder paste according to any one of claims 1 to 6 or prepared by the method according to any one of claims 7 to 9 in the field of microelectronic packaging, photovoltaics.
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