CN117506225A - Silver brazing prefabricated sheet for chip packaging and preparation method and application thereof - Google Patents
Silver brazing prefabricated sheet for chip packaging and preparation method and application thereof Download PDFInfo
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- CN117506225A CN117506225A CN202311688069.3A CN202311688069A CN117506225A CN 117506225 A CN117506225 A CN 117506225A CN 202311688069 A CN202311688069 A CN 202311688069A CN 117506225 A CN117506225 A CN 117506225A
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- silver
- powder
- chip packaging
- preform
- silver brazing
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- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 title claims abstract description 157
- 229910052709 silver Inorganic materials 0.000 title claims abstract description 84
- 239000004332 silver Substances 0.000 title claims abstract description 84
- 238000005219 brazing Methods 0.000 title claims abstract description 61
- 238000004806 packaging method and process Methods 0.000 title claims abstract description 43
- 238000002360 preparation method Methods 0.000 title claims abstract description 25
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims abstract description 35
- 239000002904 solvent Substances 0.000 claims abstract description 31
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 20
- 239000000314 lubricant Substances 0.000 claims abstract description 15
- 230000003213 activating effect Effects 0.000 claims abstract description 12
- 229910000679 solder Inorganic materials 0.000 claims abstract description 11
- 150000001875 compounds Chemical class 0.000 claims abstract description 8
- 238000004513 sizing Methods 0.000 claims abstract description 7
- 239000002245 particle Substances 0.000 claims description 40
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 39
- 238000002156 mixing Methods 0.000 claims description 33
- 239000000203 mixture Substances 0.000 claims description 27
- 238000004512 die casting Methods 0.000 claims description 26
- 229910021538 borax Inorganic materials 0.000 claims description 24
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 claims description 24
- 235000010339 sodium tetraborate Nutrition 0.000 claims description 24
- BSVBQGMMJUBVOD-UHFFFAOYSA-N trisodium borate Chemical compound [Na+].[Na+].[Na+].[O-]B([O-])[O-] BSVBQGMMJUBVOD-UHFFFAOYSA-N 0.000 claims description 24
- 239000000843 powder Substances 0.000 claims description 21
- ZIBGPFATKBEMQZ-UHFFFAOYSA-N triethylene glycol Chemical compound OCCOCCOCCO ZIBGPFATKBEMQZ-UHFFFAOYSA-N 0.000 claims description 19
- 239000002994 raw material Substances 0.000 claims description 18
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 17
- 229910021389 graphene Inorganic materials 0.000 claims description 17
- 238000005476 soldering Methods 0.000 claims description 17
- 238000004821 distillation Methods 0.000 claims description 14
- 239000000377 silicon dioxide Substances 0.000 claims description 14
- 238000009210 therapy by ultrasound Methods 0.000 claims description 12
- 229910021485 fumed silica Inorganic materials 0.000 claims description 11
- 239000012190 activator Substances 0.000 claims description 10
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 claims description 9
- 239000001509 sodium citrate Substances 0.000 claims description 9
- -1 polytetrafluoroethylene Polymers 0.000 claims description 7
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 7
- 239000004810 polytetrafluoroethylene Substances 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 4
- 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 4
- 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 4
- 239000004677 Nylon Substances 0.000 claims description 3
- 239000002775 capsule Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 239000003094 microcapsule Substances 0.000 claims description 3
- 229920001778 nylon Polymers 0.000 claims description 3
- 239000012188 paraffin wax Substances 0.000 claims description 3
- 239000011347 resin Substances 0.000 claims description 3
- 229920005989 resin Polymers 0.000 claims description 3
- 239000008188 pellet Substances 0.000 claims 1
- 239000002184 metal Substances 0.000 abstract description 11
- 229910052751 metal Inorganic materials 0.000 abstract description 11
- 238000003466 welding Methods 0.000 abstract description 8
- 229910045601 alloy Inorganic materials 0.000 abstract description 4
- 239000000956 alloy Substances 0.000 abstract description 4
- 238000002844 melting Methods 0.000 abstract description 4
- 230000008018 melting Effects 0.000 abstract description 4
- 150000002739 metals Chemical class 0.000 abstract description 4
- 239000005022 packaging material Substances 0.000 abstract description 3
- 229910002056 binary alloy Inorganic materials 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 19
- 235000012239 silicon dioxide Nutrition 0.000 description 10
- 239000000463 material Substances 0.000 description 9
- 238000012360 testing method Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 229910052738 indium Inorganic materials 0.000 description 6
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 6
- 238000007747 plating Methods 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 4
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 4
- 229910052737 gold Inorganic materials 0.000 description 4
- 239000010931 gold Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000000853 adhesive Substances 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 238000004381 surface treatment Methods 0.000 description 2
- 229910002601 GaN Inorganic materials 0.000 description 1
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 1
- 229910000846 In alloy Inorganic materials 0.000 description 1
- 101710194411 Triosephosphate isomerase 1 Proteins 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004945 emulsification Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 238000012536 packaging technology Methods 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
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
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3006—Ag 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
- B23K35/40—Making wire or rods for soldering or welding
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
- H01L21/56—Encapsulations, e.g. encapsulation layers, coatings
-
- 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
- B23K2101/00—Articles made by soldering, welding or cutting
- B23K2101/36—Electric or electronic devices
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Powder Metallurgy (AREA)
Abstract
The invention provides a silver brazing preform for chip packaging, a preparation method and application thereof. The porosity of the silver brazing preform is less than or equal to 4 percent. The silver brazing preform comprises, by weight, 60-80% of silver powder, 10-25% of tin powder, 2-10% of a solvent, 0.5-2.5% of a sizing agent, 0.5-1.5% of a lubricant and 0.1-1.0% of an activating agent. The silver powder and the tin powder in the invention belong to low-temperature solder, can form binary alloy, have lower melting point, mainly use silver powder in the alloy, have better compatibility with various metals, and can be suitable for packaging various metal parts which are limited by temperature and require high strength. The fluidity of silver powder and tin powder can be increased by adopting the impregnating compound, the lubricant and the activating agent, so that the low viscosity of the paste can be kept without adopting a high-content solvent, the porosity of less than or equal to 4% can be obtained when the preformed sheet is prepared subsequently, and the preformed sheet with low porosity can keep the characteristics of high strength, high electric conductivity and low thermal resistance. The silver brazing preform sheet provided by the invention can be used as a chip packaging material which is convenient to use and high in welding strength.
Description
Technical Field
The invention relates to the field of packaging materials, in particular to a brazing material, and more particularly relates to a silver brazing preform for chip packaging, and a preparation method and application thereof.
Background
The trend of electronic products and devices can be summarized into multifunction, high speed, large capacity, high density, light weight and miniaturization, and in order to meet these demands, many advanced packaging technologies and forms are developed in the packaging field under the promotion of the technological progress of integrated circuits.
The high power chip is packaged by nano silver paste, and is welded at 220-260 ℃ at the use temperature of more than 900 ℃ after welding. However, the difficulty of the prior art is that the heating time is too long, generally more than 2 hours is needed, the requirements on the gas environment are severe, and some of the heating processes are needed to be carried out under the nitrogen atmosphere. In addition, the nano silver paste needs to keep low viscosity for construction, the viscosity is too high to be applied to a dispensing machine, a high amount of solvent (such as 10-20%) needs to be added to low viscosity, the solvent volatilizes during high-temperature welding, and further hole defects are left, so that the porosity is large (usually 15-35%) and the control is difficult. Likewise, the conductive silver paste needs to be strictly heated and pressurized during construction, and the heating and pressurizing treatment not only damages the activity of silver, but also easily damages electronic components. In addition, in some applications, such as inserting a preformed silver solder tab as a solder thermal interface material between a processor chip and a heat spreader (TIM 1 or primary TIM technology), gold plating on the surface is required, which is costly.
Disclosure of Invention
Based on the above problems, the invention aims to provide a silver soldering preform for chip packaging, and a preparation method and application thereof, wherein the silver soldering preform can be used as a chip packaging material with convenient use and high welding strength, and the porosity is lower and is less than or equal to 4% through the adjustment of a formula or a preparation process, and the activity of silver can be kept and the advantage of low melting point can be kept.
In order to achieve the above purpose, according to one aspect of the present invention, there is provided a silver soldering preform for chip packaging, having a porosity of 4% or less, wherein the preparation raw materials comprise, in weight percentage, 60 to 80% of silver powder, 10 to 25% of tin powder, 2 to 10% of a solvent, 0.5 to 2.5% of a impregnating compound, 0.5 to 1.5% of a lubricant and 0.1 to 1.0% of an activator.
According to the technical scheme, silver powder and tin powder belong to low-temperature brazing filler metals, binary alloy can be formed, the melting point of the alloy is low, silver powder is mainly used in the alloy, the compatibility of various metals is good, and the alloy is suitable for packaging various metal parts which are limited by temperature and are required to be high in strength. The fluidity of silver powder and tin powder can be increased by adopting the impregnating compound, the lubricant and the activating agent, so that the low viscosity of the paste can be kept without adopting a high-content solvent, the porosity of less than or equal to 4% can be obtained when the preformed sheet is prepared subsequently, and the preformed sheet with low porosity can keep the characteristics of high strength, high electric conductivity and low thermal resistance. Further, the activator can activate not only the powder but also the adhesive surface when in use.
As one technical scheme of the invention, the silver powder comprises first silver powder with the particle size of 0.8-5.0 mu m and second silver powder with the particle size of 5-50 nm. The fluidity of the paste can be further increased by using silver powder with different particle diameters and tin powder, and the paste with low viscosity can be obtained by using a low-content solvent.
As a technical scheme of the invention, the weight ratio of the first silver powder in the preparation raw material is 50-70%, and the weight ratio of the second silver powder in the preparation raw material is 2-15%.
As a technical scheme of the invention, the grain size of the tin powder is 400-600 nm.
As an aspect of the present invention, the solvent includes triethylene glycol and/or diethylene glycol.
As an aspect of the present invention, the sizing agent includes fumed silica and/or precipitated silica.
As a technical scheme of the invention, the lubricant comprises at least one of paraffin microcapsules, nylon capsules, graphene and nano polytetrafluoroethylene micro powder.
As an aspect of the present invention, the activator includes at least one of sodium borate, sodium citrate, and rosin resin.
The second aspect of the present invention provides a method for preparing a silver soldering preform for chip packaging, comprising the steps of:
(1) Mixing a solvent, an impregnating compound, a lubricant and an activating agent with the dosage less than 30% in formula amount, performing ultrasonic treatment to emulsify, mixing with silver powder and tin powder to obtain a paste, and mixing the paste and the rest activating agent to obtain a mixture;
(2) The mixture is put into a reduced pressure distillation device at 40-60 ℃ and 10 DEG C -4 ～10 -6 Removing at least 95% of the solvent under Pa to obtain agglomerates;
(3) Crushing the agglomerate into powder, and then performing die casting to obtain a silver brazing preform with the porosity less than or equal to 4%, wherein the die casting has the pressurizing rate of 5-10 mm/min and the pressurizing pressure of 0.15-0.20 t/cm 2 。
In the preparation method, the impregnating compound, the lubricant and part of the activating agent are emulsified, then silver powder and tin powder are added, and the powder can be wrapped by a film layer formed by emulsification, so that the activity of the silver powder can be maintained. The activator is added for the second time, and the activator is not in direct contact with the silver powder, but is dispersed in the organic phase, so that the influence on the slurry performance caused by the contact of excessive activator with the powder is avoided. At a temperature of between 40 and 60 ℃ and 10 -4 ～10 -6 The solvent is removed in a reduced pressure distillation device under Pa, so that the influence of high temperature and high pressure on silver activity can be avoided, and the aggregation of silver powder can be prevented. And then die casting is carried out through a certain pressurizing rate and pressure, so that the powder structure is not damaged, and larger porosity is not generated.
In a third aspect, the present invention provides the use of a silver brazing preform for chip packaging, the silver brazing preform being directly attached to the joint of parts to be brazed, applying 0.2 to 0.6kg/cm 2 The silver brazing preform is directly attached to the joint of the parts to be brazed, and is welded for 15-30 s at normal temperature by ultrasonic waves with the frequency of 22-28 KHz.
Detailed Description
The silver brazing preform has lower porosity (less than or equal to 4%), lower resistivity, higher strength and wider application range. Thereby making (1)When in use, the silver brazing preform sheet can be directly attached to the joint of the parts to be brazed, and 0.2-0.6 kg/cm of the silver brazing preform sheet is applied 2 The silver brazing preform is directly attached to the joint of the parts to be brazed, and is welded for 15-30 s at normal temperature by ultrasonic waves with the frequency of 22-28 KHz.
Conventional nano silver paste cannot be directly applied to conventional metal pieces, and gold plating or silver plating is generally required on the surface of the metal piece to enhance the welding strength. The silver brazing preform for chip packaging can be subjected to surface treatment according to different application scenes, so that gold plating or silver plating treatment on the surface of a metal piece can be omitted in a specific scene, the cost is reduced, and meanwhile, the production efficiency is improved.
For example, in/Cu/Zn/Cd/Ni/Ag solder (hereinafter referred to as indium solder) has good conductivity, excellent mechanical property and corrosion resistance, is solder for welding steel, iron and nonferrous metals In the mechanical industry, and can be used for placing an indium alloy foil film at the bottom of a die before pressing a silver brazing preform sheet, so that a single-sided die-cast material is tightly attached to the indium solder. Because the compatibility of the indium solder and silver is good, the compatibility of the indium solder and steel is also good, the surface gold plating treatment of the steel is not needed when the steel is welded, so that the cost is reduced, and the silver soldering prefabricated piece is subjected to the surface treatment firstly, so that the process is easier to realize.
For materials for connecting gallium nitride, silicon carbide, sapphire and glass materials, a layer of metal indium can be plated on the silver brazing preform sheet by utilizing a vacuum evaporation technology, and the application range of the silver brazing preform sheet can be further expanded due to good wettability of the metal indium to the materials.
For the application in the automation equipment, the adhesive rosin compound can be infiltrated on one side of the silver soldering prefabricated piece, and the adhesive requirement of the technological application of grabbing, pasting, inverting and the like of the automation equipment can be met.
The porosity of the silver brazing preform sheet is less than or equal to 4 percent. The silver brazing preform comprises, by weight, 60-80% of silver powder, 10-25% of tin powder, 2-10% of a solvent, 0.5-2.5% of a sizing agent, 0.5-1.5% of a lubricant and 0.1-1.0% of an activating agent. The weight percent of silver powder may be, but is not limited to, 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78%, 80%. The weight percent of tin powder may be, but is not limited to, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 25%. The weight percent of solvent may be, but is not limited to, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%. The weight percent of the sizing agent can be, but is not limited to, 0.5%, 0.8%, 1.0%, 1.3%, 1.5%, 1.7%, 2.0%, 2.2%, 2.5%. The weight percent of the lubricant may be, but is not limited to, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%. The weight percent of activator may be, but is not limited to, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%.
Wherein the silver powder comprises a first silver powder with the particle size of 0.8-5.0 mu m and a second silver powder with the particle size of 5-50 nm. The silver powder with different particle size collocations can improve the filling volume and reduce the porosity, wherein the silver powder with large particle size mainly regulates and controls/reduces the viscosity of the slurry, and the silver powder with small particle size mainly reduces the melting point of the slurry. The weight ratio of the first silver powder in the preparation raw material is 50-70%, and the weight ratio of the second silver powder in the preparation raw material is 2-15%. The grain size of the tin powder is 400-600 nm. The solvent comprises triethylene glycol and/or diethylene glycol.
The sizing agent comprises silicon dioxide fumed silica and/or deposited silica. The lubricant comprises at least one of paraffin microcapsules, nylon capsules, graphene and nano polytetrafluoroethylene micro powder. The activator includes at least one of sodium borate, sodium citrate, and rosin resin.
The preparation method of the silver soldering preform for chip packaging of the present invention may include the following steps.
(1) Mixing solvent, impregnating agent, lubricant and activating agent with dosage less than 30% according to formula, ultrasonic treating to emulsify, mixing with silver powder and tin powder to obtain paste, and mixing the paste and the rest activating agent to obtain the mixture.
(2) Mixing the mixtureIn a reduced pressure distillation apparatus at 40-60 ℃ and 10 DEG C -4 ～10 -6 Removing at least 95% of the solvent under Pa to obtain agglomerates.
(3) Crushing the agglomerate into powder, and then performing die casting to obtain a silver brazing preform with the porosity less than or equal to 4%, wherein the pressurizing rate of die casting is 5-10 mm/min, and the pressurizing pressure is 0.15-0.20 t/cm 2 。
The silver brazing preform with a thickness of 0.05-0.50 mm, a porosity of 4% or less and a resistivity of 7.5X10 are obtained by the method -6 Ω·cm。
For a better description of the objects, technical solutions and advantageous effects of the present invention, the present invention will be further described with reference to specific examples. It should be noted that the following implementation of the method is a further explanation of the present invention and should not be taken as limiting the present invention.
Example 1
The raw materials for preparing the silver brazing preform for chip packaging of this example included 65wt.% of silver powder having a particle size of 2 μm, 20wt.% of tin powder having a particle size of 500nm, 10wt.% of silver powder having a particle size of 5nm, 3wt.% of triethylene glycol, 1.0wt.% of fumed silica, 0.8wt.% of graphene, and 0.2wt.% of sodium borate.
The preparation method of the silver soldering preform for chip packaging in the embodiment comprises the following steps.
(1) Mixing triethylene glycol, silicon dioxide, graphene and 20% sodium borate, performing ultrasonic treatment to emulsify, mixing with silver powder and tin powder to obtain a paste, and mixing the paste with the rest 80% sodium borate to obtain a mixture.
(2) Placing the mixture in a reduced pressure distillation apparatus at 50deg.C and 10deg.C -5 Removing at least 95% of the solvent under Pa to obtain agglomerates.
(3) Crushing the agglomerate into powder, and then performing die casting to obtain a silver brazing preform, wherein the die casting has a pressurizing rate of 7mm/min and a pressurizing pressure of 0.20t/cm 2 。
Example 2
The raw materials for preparing the silver brazing preform for chip packaging of this example included 60wt.% of silver powder having a particle size of 1 μm, 20wt.% of tin powder having a particle size of 500nm, 15wt.% of silver powder having a particle size of 50nm, 3wt.% of triethylene glycol, 1.0wt.% of fumed silica, 0.8wt.% of nano polytetrafluoroethylene micropowder, and 0.2wt.% of sodium borate.
The preparation method of the silver soldering preform for chip packaging in the embodiment comprises the following steps.
(1) Mixing triethylene glycol, silicon dioxide, nano polytetrafluoroethylene micro powder and sodium borate with the dosage of 20 percent, performing ultrasonic treatment to emulsify, mixing with silver powder and tin powder to obtain a paste, and mixing the paste with the rest 80 percent of sodium borate to obtain a mixture.
(2) Placing the mixture in a reduced pressure distillation apparatus at 50deg.C and 10deg.C -5 Removing at least 95% of the solvent under Pa to obtain agglomerates.
(3) Crushing the agglomerate into powder, and then performing die casting to obtain a silver brazing preform, wherein the die casting has a pressurizing rate of 7mm/min and a pressurizing pressure of 0.20t/cm 2 。
Example 3
The raw materials for preparing the silver brazing preform for chip packaging of this example included 60wt.% of silver powder having a particle size of 5 μm, 20wt.% of tin powder having a particle size of 500nm, 15wt.% of silver powder having a particle size of 10nm, 3.5wt.% of diethylene glycol, 0.5wt.% of fumed silica, 0.8wt.% of graphene, and 0.2wt.% of sodium citrate.
The preparation method of the silver soldering preform for chip packaging in the embodiment comprises the following steps.
(1) Diethylene glycol, silicon dioxide, graphene and sodium citrate with the dosage of 20% are mixed, then ultrasonic treatment is carried out to emulsify, then the mixture is mixed with silver powder and tin powder to obtain a paste material, and the paste material and the rest 80% of sodium citrate are mixed to obtain a mixture.
(2) Placing the mixture in a reduced pressure distillation apparatus at 50deg.C and 10deg.C -5 Removing at least 95% of the solvent under Pa to obtain agglomerates.
(3) Crushing the agglomerate into powder, and then performing die casting to obtain a silver brazing preform, wherein the die casting has a pressurizing rate of 7mm/min and a pressurizing pressure of 0.20t/cm 2 。
Example 4
The raw materials for preparing the silver brazing preform for chip packaging of this example included 65wt.% of silver powder having a particle size of 1 μm, 15wt.% of tin powder having a particle size of 400nm, 15wt.% of silver powder having a particle size of 10nm, 3.5wt.% of triethylene glycol, 0.5wt.% of precipitated silica, 0.6wt.% of nano polytetrafluoroethylene micropowder, and 0.4wt.% of sodium citrate.
The preparation method of the silver brazing preform sheet of the present embodiment includes the following steps.
(1) Mixing triethylene glycol, silicon dioxide, nano polytetrafluoroethylene micro powder and sodium citrate with the dosage of 20 percent, performing ultrasonic treatment to emulsify, mixing with silver powder and tin powder to obtain a paste, and mixing the paste with the rest 80 percent of sodium citrate to obtain a mixture.
(2) Placing the mixture in a reduced pressure distillation apparatus at 50deg.C and 10deg.C -5 Removing at least 95% of the solvent under Pa to obtain agglomerates.
(3) Crushing the agglomerate into powder, and then performing die casting to obtain a silver brazing preform, wherein the die casting has a pressurizing rate of 7mm/min and a pressurizing pressure of 0.20t/cm 2 。
Example 5
The raw materials for preparing the silver brazing preform for chip packaging of this example included 65wt.% of silver powder having a particle size of 2 μm, 15wt.% of tin powder having a particle size of 500nm, 15wt.% of silver powder having a particle size of 10nm, 3.5wt.% of diethylene glycol, 0.5wt.% of fumed silica, 0.8wt.% of graphene, and 0.2wt.% of sodium borate.
The preparation method of the silver brazing preform sheet of the present embodiment includes the following steps.
(1) Mixing diethylene glycol, silicon dioxide, graphene and 20% sodium borate, performing ultrasonic treatment to emulsify, mixing with silver powder and tin powder to obtain a paste, and mixing the paste with the rest 80% sodium borate to obtain a mixture.
(2) The mixture was distilled at 55℃and 10℃in a reduced pressure distillation apparatus -6 Removing at least 95% of the solvent under Pa to obtain agglomerates.
(3) Crushing the agglomerate into powder, and then performing die casting to obtain a silver brazing preform, wherein the compression rate of die casting is 10mm/min, the pressurizing pressure is 0.15t/cm 2 。
Comparative example 1
The raw materials for preparing the silver brazing preform for chip packaging of this comparative example included 65wt.% of silver powder having a particle size of 2 μm, 20wt.% of tin powder having a particle size of 500nm, 10wt.% of silver powder having a particle size of 5nm, 3wt.% of triethylene glycol, 1.0wt.% of fumed silica, 0.8wt.% of graphene, and 0.2wt.% of sodium borate.
The preparation method of the silver soldering preform for chip packaging of the comparative example comprises the following steps.
(1) Mixing triethylene glycol, silicon dioxide, graphene and 20% sodium borate, performing ultrasonic treatment to emulsify, mixing with silver powder and tin powder to obtain a paste, and mixing the paste with the rest 80% sodium borate to obtain a mixture.
(2) Placing the mixture in a reduced pressure distillation apparatus at 50deg.C and 10deg.C -5 Removing at least 95% of the solvent under Pa to obtain agglomerates.
(3) Crushing the agglomerate into powder, and then performing die casting to obtain a silver brazing preform, wherein the die casting has a pressurizing rate of 7mm/min and a pressurizing pressure of 1.1t/cm 2 。
Comparative example 2
The raw materials for preparing the silver brazing preform for chip packaging of this comparative example included 75wt.% of silver powder having a particle size of 2 μm, 20wt.% of silver powder having a particle size of 5nm, 3wt.% of triethylene glycol, 1.0wt.% of fumed silica, 0.8wt.% of graphene, and 0.2wt.% of sodium borate.
The preparation method of the silver soldering preform for chip packaging of the comparative example comprises the following steps.
(1) Triethylene glycol, silicon dioxide, graphene and 20% sodium borate are mixed, then ultrasonic treatment is carried out to emulsify, then the mixture is mixed with silver powder to obtain a paste, and the paste and the rest 80% sodium borate are mixed to obtain a mixture.
(2) Placing the mixture in a reduced pressure distillation apparatus at 50deg.C and 10deg.C -5 Removing at least 95% of the solvent under Pa to obtain agglomerates.
(3) Crushing the agglomerate into powder, and then performing die casting to obtain silver brazing preformThe pressurizing rate of the die casting molding is 7mm/min, and the pressurizing pressure is 0.20t/cm 2 。
Comparative example 3
The raw materials for preparing the silver brazing preform for chip packaging of this comparative example included 60wt.% of silver powder having a particle size of 2 μm, 20wt.% of tin powder having a particle size of 500nm, 7wt.% of silver powder having a particle size of 5nm, 12wt.% of triethylene glycol, 0.8wt.% of graphene, and 0.2wt.% of sodium borate.
The preparation method of the silver soldering preform for chip packaging of the comparative example comprises the following steps.
(1) Mixing triethylene glycol, graphene and 20% sodium borate, performing ultrasonic treatment to emulsify, mixing with silver powder and tin powder to obtain a paste, and mixing the paste with the rest 80% sodium borate to obtain a mixture.
(2) Placing the mixture in a reduced pressure distillation apparatus at 50deg.C and 10deg.C -5 Removing at least 95% of the solvent under Pa to obtain agglomerates.
(3) Crushing the agglomerate into powder, and then performing die casting to obtain a silver brazing preform, wherein the die casting has a pressurizing rate of 7mm/min and a pressurizing pressure of 0.20t/cm 2 。
Comparative example 4
The raw materials for preparing the silver brazing preform for chip packaging of this comparative example included 60wt.% of silver powder having a particle size of 2 μm, 20wt.% of tin powder having a particle size of 500nm, 6wt.% of silver powder having a particle size of 5nm, 12.8wt.% of triethylene glycol, 1.0wt.% of fumed silica, and 0.2wt.% of sodium borate.
The preparation method of the silver soldering preform for chip packaging of the comparative example comprises the following steps.
(1) Mixing triethylene glycol, silicon dioxide and 20% sodium borate, performing ultrasonic treatment to emulsify, mixing with silver powder and tin powder to obtain a paste, and mixing the paste with the rest 80% sodium borate to obtain a mixture.
(2) Placing the mixture in a reduced pressure distillation apparatus at 50deg.C and 10deg.C -5 Removing at least 95% of the solvent under Pa to obtain agglomerates.
(3) Crushing the agglomerate into powder, and then performing compression casting to obtain a silver brazing preform,the pressurizing rate of the die casting molding is 7mm/min, and the pressurizing pressure is 0.20t/cm 2 。
Comparative example 5
The raw materials for preparing the silver brazing preform for chip packaging of this comparative example included 60wt.% of silver powder having a particle size of 2 μm, 20wt.% of tin powder having a particle size of 500nm, 6wt.% of silver powder having a particle size of 5nm, 12.2wt.% of triethylene glycol, 1.0wt.% of fumed silica, and 0.8wt.% of graphene.
The preparation method of the silver soldering preform for chip packaging of the comparative example comprises the following steps.
(1) And mixing triethylene glycol, silicon dioxide and graphene, performing ultrasonic treatment to emulsify, and mixing with silver powder and tin powder to obtain a mixture.
(2) Placing the mixture in a reduced pressure distillation apparatus at 50deg.C and 10deg.C -5 Removing at least 95% of the solvent under Pa to obtain agglomerates.
(3) Crushing the agglomerate into powder, and then performing die casting to obtain a silver brazing preform, wherein the die casting has a pressurizing rate of 7mm/min and a pressurizing pressure of 0.20t/cm 2 。
The silver brazing preform of examples 1 to 5 and comparative examples 1 to 5 were tested for porosity, electrical resistivity, thermal resistance and solderability under the following test conditions, and the test results are shown in table 1.
Test conditions:
(1) And testing the porosity by adopting a porosity tester, and testing the resistivity by adopting a testing resistivity tester.
(2) Thermal resistance test: and using a chip with a packaging gap of 0.5mm between a chip body and an upper cover, wherein the power consumption of the single chip is more than 200W, respectively taking the silver soldering prefabricated pieces of the examples 1-5 and the comparative examples 1-5 as connecting layers of the chip body and the upper cover, and obtaining the thermal resistance by measuring the temperature difference of the chip and the temperature of the upper cover and dividing the temperature difference by the power consumption of the chip. The lower the thermal resistance value, the higher the heat transfer efficiency.
(3) Welding performance test: the silver brazing prefabricated pieces of examples 1 to 5 and comparative examples 1 to 5 are respectively welded together by two copper blocks with equal areas, and are separated by pulling the copper blocks by a pulling machine, and the breaking force is divided by the area to obtain the welding strength.
Table 1 results of test of performance of silver brazing preform for examples 1 to 5 and comparative examples 1 to 5
As is apparent from the results of Table 1, the silver brazing preform sheets of examples 1 to 5 were low in porosity, resistivity and thermal resistance, and high in weld strength at a temperature of more than 210℃because the silver brazing preform sheet of the present invention was obtained by adding a sizing agent, a lubricant and an activator to the silver powder as main materials to reduce the solvent content and also to maintain the activity of the silver powder, and thus a preform sheet having a porosity of 4% or less was obtained, thereby maintaining the characteristics of high strength, high electrical conductivity and low thermal resistance.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the present invention can be modified or substituted without departing from the spirit and scope of the technical solution of the present invention.
Claims (10)
1. The silver brazing preform for chip packaging is characterized in that the porosity is less than or equal to 4%, and the preparation raw materials comprise, by weight, 60-80% of silver powder, 10-25% of tin powder, 2-10% of a solvent, 0.5-2.5% of a impregnating compound, 0.5-1.5% of a lubricant and 0.1-1.0% of an activating agent.
2. The silver brazing preform for chip packaging according to claim 1, wherein the silver powder comprises a first silver powder having a particle size of 0.8 to 5.0 μm and a second silver powder having a particle size of 5 to 50 nm.
3. The silver brazing preform for chip packaging according to claim 2, wherein the weight ratio of the first silver powder to the raw material for production is 50 to 70%, and the weight ratio of the second silver powder to the raw material for production is 2 to 15%.
4. The silver brazing preform for chip packaging according to claim 1, wherein the particle size of the tin powder is 400 to 600nm.
5. The silver solder preform for chip packaging of claim 1, wherein the solvent comprises triethylene glycol and/or diethylene glycol.
6. The silver braze preform for chip packaging of claim 1, wherein the sizing agent comprises fumed silica and/or precipitated silica.
7. The pre-silver braze pellet for chip packaging of claim 1, wherein the lubricant comprises at least one of paraffin microcapsules, nylon capsules, graphene, and nano polytetrafluoroethylene micropowder.
8. The silver solder preform for chip packaging of claim 1, wherein the activator comprises at least one of sodium borate, sodium citrate, and rosin resin.
9. The preparation method of the silver soldering preform for chip packaging is characterized by comprising the following steps:
(1) Mixing a solvent, an impregnating compound, a lubricant and an activating agent with the dosage less than 30% in formula amount, performing ultrasonic treatment to emulsify, mixing with silver powder and tin powder to obtain a paste, and mixing the paste and the rest activating agent to obtain a mixture;
(2) The mixture is put into a reduced pressure distillation device at 40-60 ℃ and 10 DEG C -4 ～10 -6 Removing at least 95% of the solvent under Pa to obtain agglomerates;
(3) Agglomerating the aboveCrushing the body into powder, and then performing die casting to obtain a silver brazing preform with the porosity less than or equal to 4%, wherein the die casting has the pressurizing rate of 5-10 mm/min and the pressurizing pressure of 0.15-0.20 t/cm 2 。
10. Use of a silver brazing preform for chip packaging according to any one of claims 1 to 8 or a silver brazing preform for chip packaging according to claim 9, wherein the silver brazing preform is directly attached to the joint of the parts to be brazed by applying 0.2 to 0.6kg/cm 2 The silver brazing preform is directly attached to the joint of the parts to be brazed, and is welded for 15-30 s at normal temperature by ultrasonic waves with the frequency of 22-28 KHz.
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| CN202311688069.3A CN117506225A (en) | 2023-12-11 | 2023-12-11 | Silver brazing prefabricated sheet for chip packaging and preparation method and application thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311688069.3A CN117506225A (en) | 2023-12-11 | 2023-12-11 | Silver brazing prefabricated sheet for chip packaging and preparation method and application thereof |
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