CN117961361A - High-temperature lead-free micro-metallurgical solder, solder paste, preparation method and welding spot - Google Patents
High-temperature lead-free micro-metallurgical solder, solder paste, preparation method and welding spot Download PDFInfo
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- 238000003466 welding Methods 0.000 title claims abstract description 145
- 229910000679 solder Inorganic materials 0.000 title claims abstract description 132
- 238000002360 preparation method Methods 0.000 title claims description 13
- 239000000843 powder Substances 0.000 claims abstract description 276
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 267
- 239000000956 alloy Substances 0.000 claims abstract description 267
- 238000002844 melting Methods 0.000 claims abstract description 68
- 230000008018 melting Effects 0.000 claims abstract description 68
- 238000004806 packaging method and process Methods 0.000 claims abstract description 23
- 238000010310 metallurgical process Methods 0.000 claims abstract description 19
- 238000010438 heat treatment Methods 0.000 claims abstract description 14
- 238000001816 cooling Methods 0.000 claims abstract description 10
- 239000000203 mixture Substances 0.000 claims abstract description 7
- 238000012423 maintenance Methods 0.000 claims abstract description 5
- 229910052751 metal Inorganic materials 0.000 claims description 87
- 239000002184 metal Substances 0.000 claims description 87
- 229910000521 B alloy Inorganic materials 0.000 claims description 45
- 238000000034 method Methods 0.000 claims description 34
- 238000005476 soldering Methods 0.000 claims description 29
- 239000010949 copper Substances 0.000 claims description 27
- 229910001339 C alloy Inorganic materials 0.000 claims description 22
- 229910017944 Ag—Cu Inorganic materials 0.000 claims description 16
- 229910052718 tin Inorganic materials 0.000 claims description 14
- 238000005272 metallurgy Methods 0.000 claims description 12
- 239000002245 particle Substances 0.000 claims description 10
- 229910020935 Sn-Sb Inorganic materials 0.000 claims description 9
- 229910008757 Sn—Sb Inorganic materials 0.000 claims description 9
- 229910052802 copper Inorganic materials 0.000 claims description 9
- 150000002739 metals Chemical class 0.000 claims description 8
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 7
- 238000002156 mixing Methods 0.000 claims description 7
- 229910052759 nickel Inorganic materials 0.000 claims description 7
- 229910052709 silver Inorganic materials 0.000 claims description 6
- 230000004907 flux Effects 0.000 claims description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 239000004332 silver Substances 0.000 claims description 3
- 238000003756 stirring Methods 0.000 claims 1
- 229910000765 intermetallic Inorganic materials 0.000 abstract description 26
- 238000013461 design Methods 0.000 abstract description 10
- 238000011068 loading method Methods 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 10
- 238000009792 diffusion process Methods 0.000 description 10
- 230000009286 beneficial effect Effects 0.000 description 8
- 239000007787 solid Substances 0.000 description 7
- 239000011159 matrix material Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 239000012071 phase Substances 0.000 description 5
- 229910001325 element alloy Inorganic materials 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 229910006640 β-Sn Inorganic materials 0.000 description 4
- 229910006632 β—Sn Inorganic materials 0.000 description 4
- 238000004377 microelectronic Methods 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- 229910007662 Sn3Sb2 Inorganic materials 0.000 description 2
- 230000001351 cycling effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005538 encapsulation Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 238000010309 melting process Methods 0.000 description 2
- 239000002923 metal particle Substances 0.000 description 2
- 210000003205 muscle Anatomy 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 238000003723 Smelting Methods 0.000 description 1
- 229910007116 SnPb Inorganic materials 0.000 description 1
- 229910006913 SnSb Inorganic materials 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 229910052728 basic metal Inorganic materials 0.000 description 1
- 150000003818 basic metals Chemical class 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000004100 electronic packaging Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
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- 230000007613 environmental effect Effects 0.000 description 1
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- 235000019580 granularity Nutrition 0.000 description 1
- 239000000383 hazardous chemical Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 229910052755 nonmetal Inorganic materials 0.000 description 1
- 150000002843 nonmetals Chemical class 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 238000012536 packaging technology Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
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- 238000010992 reflux Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
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- 239000012265 solid product Substances 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
- B23K35/40—Making wire or rods for soldering or welding
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
Abstract
The high-temperature lead-free micro-metallurgical solder comprises alloy A powder and alloy B powder; the difference between the melting point of the alloy A and the melting point of the alloy B is 70-150 ℃; the mass ratio of the alloy powder A is 30-10%, and the mass ratio of the alloy powder B is 70-90%. The welding temperature curve is completed in three sections, namely a heating stage, a micro-metallurgical welding stage and a cooling stage; the temperature interval range of the micro-metallurgical temperature setting in the micro-metallurgical welding stage is 280-350 ℃; the maintenance time of the micro-metallurgical welding stage is 120-240 seconds; the alloy composition design of the high-temperature lead-free micro-metallurgical solder is matched with specific reflow temperature and time, the micro-metallurgical process occurs when the solder joint is formed, a large amount of intermetallic compounds are generated, the Sn phase with low melting point is consumed, the service temperature of the solder joint is improved, the packaging strength of the solder joint and the loading capacity of temperature cycle can be increased, and the high-reliability lead-free high-temperature solder joint is obtained.
Description
Technical Field
The invention relates to the technical field of brazing solder manufacturing, in particular to lead-free micro-metallurgical solder and tin paste for high-temperature welding, and preparation and welding methods and welding spots.
Background
The soldering materials used in the packaging of microelectronic and power semiconductor devices first require consideration of the application temperature environment of the soldered product. In the prior art, in order to withstand medium and high temperatures, lead-containing solders having a relatively high melting point containing lead of 90% or more are generally used. However, in view of environmental friendliness, the hazardous substances restriction (RoHS) directive issued at 7/1/2006 has prohibited the use of lead-based solders in the electronic interconnect and electronic packaging industries. It is desirable to replace the SnPb solder alloy with a lead-free solder alloy. However, the lead-free solder alloy in the prior art cannot meet the requirement of medium-high temperature welding, or has high content of high-value noble metal, so that the cost is high, and how to develop a low-cost lead-free medium-high temperature solder is a problem to be solved.
In the prior art, when soldering a device to be soldered to a Printed Circuit Board (PCB), the same board may typically be exposed to multiple reflows. The temperature set by the reflow soldering apparatus in soldering is usually higher than the melting point of the solder so that there is a temperature difference or energy difference that can support the solder joint to be melted to finish soldering, so that the solder joint that has finished soldering needs to have medium-high temperature resistance to resist the multiple reflow soldering process without causing any functional failure when reflowing many times. If the melting point of the welded joint is low, the welded joint will melt twice during reflow, thereby affecting the reliability of the welded joint.
Particularly in some high-reliability application occasions, the temperature range which the welding spot needs to withstand is wide, the welding spot is not expected to be secondarily melted during reflow or service, and the influence of temperature and time under the reflow and service conditions can be resisted.
Therefore, it is very challenging to develop a lead-free high temperature solder which has suitable soldering temperature, can withstand multiple reflows and temperature cycling under service conditions, and also has both price and process implementation conditions during soldering.
Noun interpretation:
the term "alloy" is used in the present specification to mean a solid product of metallic nature obtained by melting one metal in combination with another metal or metals or non-metals, and cooling and solidifying.
Disclosure of Invention
The technical scheme of the invention overcomes the defects of the prior art, solves the problem that the service temperature of the lead-free high-temperature solder is insufficient relative to the welding temperature after welding by taking the packaging technology as a break and matching with a specific solder formula, develops the high-temperature lead-free micro-metallurgical solder, can realize lead-free welding under the high-temperature condition, and has reliable temperature cyclic loading capacity.
The technical scheme for solving the technical problems is that the high-temperature lead-free micro-metallurgical solder comprises alloy A powder and alloy B powder; the difference between the melting point of the alloy A and the melting point of the alloy B is 70-150 ℃; the mass ratio of the alloy powder A is 30-10%, and the mass ratio of the alloy powder B is 70-90%.
The A alloy comprises Sn-Ag-Cu alloy; the Sn-Ag-Cu alloy comprises the following components in percentage by mass: 95.5% -99%, ag:0.3% -3.8%, cu:0.5% -0.7%.
The alloy A comprises an Sn-Sb alloy, wherein the mass ratio of each component in the alloy is Sn:89.5 to 95 percent of Sb, 5 to 10 percent of Ni:0% -0.5%.
The B alloy comprises Sn-Sb-Ag-Cu alloy, and the mass ratio of each component in the alloy is Sn:37% -42%, sb 35% -50%, ag:12% -15%, cu 0% -6%, bi:0% -3%; and the mass percentage of Sn, sb, ag, cu in the B alloy satisfies the relation: a=1.4633b+0.366c+1.558d+e, wherein a is Sn mass percent, b is Sb mass percent, c is Ag mass percent, d is Cu mass percent, and e is in a range of-0.4-0.2.
The high-temperature lead-free micro-metallurgical solder also comprises C alloy powder; the C alloy comprises Sn-Sb alloy, wherein the mass ratio of each component in the alloy is Sn:89.5 to 95 percent of Sb, 5 to 10 percent of Ni:0% -0.5%; the mass ratio of the alloy powder A is 25-5%, the mass ratio of the alloy powder B is 70-90%, and the mass ratio of the alloy powder C is 25-5%.
The particle size of the alloy powder A is 1-50 mu m; the particle size of the alloy powder B is 1-50 mu m; the particle size of the C alloy powder is 1-50 mu m.
The high-temperature lead-free micro-metallurgical solder also comprises micro-nano D metal powder; the melting point temperature of the micro-nano D metal is more than 400 ℃; the mass ratio of the alloy powder A is 10-27%, the mass ratio of the alloy powder B is 70-87%, and the mass ratio of the metal powder D is 0.1-3%.
The high-temperature lead-free micro-metallurgical solder comprises any one of the following technical characteristics: characteristic TC1: the metal D is Ag; characteristic TC2: the metal D is Cu; characteristic TC3: the metal D is Fe; characteristic TC4: the metal D is Ce; characteristic TC5: the metal D is Ni; characteristic TC6: the metal D is Co; characteristic TC7: the metal D is Mn; characteristic TC8: the metal D is silver-coated copper AgCu, and the mass ratio of the components is 10-30% of Ag and 70-90% of Cu.
The particle size of the alloy powder A is 1-50 mu m; the particle size of the alloy powder B is 1-50 mu m; the size of the micro-nano D metal powder is 100 nm-10 mu m.
The technical scheme for solving the technical problems in the application can also be high-temperature lead-free micro-metallurgical solder paste, which comprises the high-temperature lead-free micro-metallurgical solder.
The technical scheme for solving the technical problems in the application can also be a preparation method for high-temperature lead-free micro-metallurgical solder, wherein the A alloy powder and the B alloy powder are respectively and independently prepared; the difference between the melting point of the alloy A and the melting point of the alloy B is 70-150 ℃; mixing the alloy powder A and the alloy powder B to form micro-metallurgical welding powder; the mass ratio of the alloy powder A is 10-30%, and the mass ratio of the alloy powder B is 70-90%.
The preparation method of the high-temperature lead-free micro-metallurgical solder is used for independently preparing C alloy powder; mixing the alloy powder A, the alloy powder B and the alloy powder C to form micro-metallurgical welding powder; the mass ratio of the alloy powder A is 25-5%, the mass ratio of the alloy powder B is 70-90%, and the mass ratio of the alloy powder C is 25-5%.
According to the preparation method of the high-temperature lead-free micro-metallurgical solder, micro-nano D metal powder is independently prepared, and the melting point temperature of the micro-nano D metal is higher than 400 ℃; the size of the micro-nano D metal powder is 100 nm-10 mu m (micrometers); mixing the alloy powder A, the alloy powder B and the metal powder D to form micro-metallurgical welding powder; the mass ratio of the alloy powder A is 10-27%, the mass ratio of the alloy powder B is 70-87%, and the mass ratio of the metal powder D is 0.1-3%.
The preparation method of the high-temperature lead-free micro-metallurgical solder is based on micro-metallurgical welding powder, and the flux or the soldering flux matched with the micro-metallurgical welding powder is added to be stirred into micro-metallurgical tin paste and tin glue.
The technical scheme for solving the technical problems can also be a high-temperature lead-free micro-metallurgical welding method, which is based on the high-temperature lead-free micro-metallurgical solder or based on the high-temperature lead-free micro-metallurgical solder paste welding temperature curve, and comprises three stages, namely a heating stage, a micro-metallurgical welding stage and a cooling stage; the temperature interval range of the micro-metallurgical temperature setting in the micro-metallurgical welding stage is 280-350 ℃; the maintenance time of the micro-metallurgy stage is 120-240 seconds; micro-metallurgical packaging solder a micro-metallurgical process occurs during soldering.
In the high-temperature lead-free micro-metallurgical welding method, the temperature in the heating stage is raised from 25 ℃ to 280 ℃, the heating rate is 3 ℃/s to 6 ℃/s, and the heating time is 45 seconds to 90 seconds; the temperature in the cooling stage is cooled from 350 ℃ to 80 ℃ at a cooling rate of 3-8 ℃/s.
The technical scheme for solving the technical problems in the application can also be a welding spot formed by high-temperature lead-free micro-metallurgical welding, wherein the welding spot comprises Sn-Sb-Ag-Cu alloy, and the mass ratio of each component in the alloy is Sn:37% -42%, sb 28% -44%, ag:8% -13%, 0% -7% of Cu, bi:0% -3% and 0% -0.1% of other metals, wherein the other metals comprise any one or more of Ni, fe, co, mn, ce, au; the mass percent of Sn, sb, ag, cu in the welding spot alloy satisfies the relation: a=1.4633b+0.366c+1.558d+e, wherein a is Sn in mass percent, b is Sb in mass percent, c is Ag in mass percent, d is Cu in mass percent, and e is-0.3-0.
Compared with the prior art, the invention has one of the beneficial effects that: the multi-alloy component solder with the stepped melting point comprises at least two separately prepared alloy powders, which are different from the conventional single alloy powders. The technology combines welding process control, utilizes the melting point difference of two alloys, in the welding process, besides the conventional melting process to form a new alloy, the micro-metallurgical process of coexistence of liquid molten alloy and solid alloy also occurs, and the time of the micro-metallurgical process is reasonably controlled by combining temperature control in the process, so that not only is the atomic diffusion carried out on the solder and the bonding pad, but also the atomic diffusion is carried out between metal powders with different melting points among the solder to generate a large amount of intermetallic compounds, thereby further improving the connection reliability of the welding position and improving the high-temperature tolerance capability of the welding position.
Compared with the prior art, the invention has one of the beneficial effects that: the alloys with different melting points are respectively and independently prepared into powder, and then the powder of the different alloys is mixed together according to the set component ratio to be used as high-temperature lead-free micro-metallurgical solder; as the melting point temperature difference of different alloys is large enough, the solder is matched with the specific micro-metallurgical welding temperature and time in the welding process, and the formed welding spot contains a large amount of intermetallic compounds, so that grains are refined, the grain growth speed of the welding spot in the service process is prevented, the dislocation movement resistance among the grains is increased, the packaging strength of the welding spot is increased, and the reliability of the welding spot is improved.
Compared with the prior art, the invention has one of the beneficial effects that: the micro-metallurgical packaging solder contains metal powder with different melting points, in the heating process, the relatively low-melting-point alloy powder A or C is melted first, the relatively high-melting-point alloy powder B or D is still solid, the medium-temperature metal melt is connected with high-temperature metal particles to form a structure similar to human muscle and skeleton, so that the collapse resistance of the solder is improved, the collapse resistance is particularly important in the narrow-interval high-density packaging of the microelectronic integrated circuit, and the risk of tin connection short circuit is reduced.
Compared with the prior art, the invention has one of the beneficial effects that: alloy powder A and alloy powder B, alloy powder B and alloy powder C; the micro-metallurgical process can be generated between the A alloy powder and the D metal powder, between the B alloy powder and the D metal powder and between the C alloy powder and the D metal powder due to enough melting point difference, and atomic diffusion bonding can be generated between metal atoms of different components to generate a large amount of intermetallic compounds, so that intermetallic compounds with higher melting points are formed, and the structure is firmer.
Compared with the prior art, the invention has one of the beneficial effects that: the time for micro-metallurgical welding is controlled to be at least 120 seconds, so that enough time is provided for the process, the coexistence time between the liquid molten alloy and the solid alloy or metal is long enough, the micro-metallurgical process can be more fully completed, and the application of medium-temperature encapsulation and high-temperature service of the welding piece can be realized.
Compared with the prior art, the invention has one of the beneficial effects that: the combination of the alloy with multiple components strengthens the micro-metallurgical process, and the atomic diffusion bonding is more sufficient and has more abundant layers, so that the final welding strength is higher.
Compared with the prior art, the invention has one of the beneficial effects that: the alloy composition design is matched with a specific reflux curve, and a micro-metallurgical process occurs when a welding spot is formed, so that a large amount of intermetallic compounds are generated, and the packaging strength of the welding spot and the load capacity of temperature cycle can be increased.
Compared with the prior art, the invention has one of the beneficial effects that: the powder with different granularities can form a proper interface state in the welding process, the size of the micro-nano D metal powder is smaller than that of the A alloy powder and the B alloy powder, a large number of nucleation points are formed, grains are refined, the D metal powder with high melting point is easier to uniformly diffuse, and more intermetallic compounds are formed.
Drawings
FIG. 1 is a table of components of examples and comparative examples;
FIG. 2 is a graph of test result data for examples and comparative examples;
FIG. 3 is a bar graph of test results for examples and comparative examples;
FIG. 4 is a graph showing the soldering temperature profile of a high temperature lead-free micro-metallurgical solder;
FIG. 5 is a graph showing the soldering temperature of a high temperature lead-free micro-metallurgical solder;
FIG. 6 is an SEM image of a solder joint after high temperature lead free micro-metallurgical soldering in example 4;
FIG. 7 is an EDS diagram of a weld spot after high temperature lead free micro-metallurgical welding of example 4;
FIG. 8 is an SEM image of a solder ball after four reflow temperature shocks in a reflow oven at a package temperature of 260 ℃ after high temperature lead-free micro-metallurgical soldering of example 4;
fig. 9 is an EDS diagram of example 4 after four reflow temperature shocks in a reflow oven at a package temperature of 260 c after high temperature lead free micro-metallurgical bonding.
Detailed Description
The present invention is described in further detail below with reference to the accompanying drawings.
The term "prepared from …" as used herein is synonymous with "comprising". The terms "comprising," "having," "including," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus. The conjunction "consisting of …" excludes any unspecified element, step or component.
If used in a claim, such phrase will cause the claim to be closed, such that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of …" appears in a clause of the claim body, rather than immediately following the subject, it is limited to only the elements described in that clause; other elements are not excluded from the stated claims as a whole. Where an equivalent amount, concentration, or other value or parameter is expressed as a range, preferred range, or in terms of a range bounded by a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when ranges "1 to 5" are disclosed, the described ranges should be construed to include ranges "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. When a numerical range is described herein, unless otherwise indicated, the range is intended to include its endpoints and all integers and fractions within the range. The singular forms include plural referents unless the context clearly dictates otherwise. "optional" or "any" means that the subsequently described event or event may or may not occur, and that the description includes both cases where the event occurs and cases where the event does not. Approximating language in the specification and claims may be applied to modify an amount that would not limit the application to the specific amount, but rather that the application is limited to an amount that would be acceptable without resulting in a change in the basic functionality involved. Accordingly, the use of "about," "approximately" or the like to modify a numerical value is intended to mean that the present application is not limited to the precise numerical value. In some examples, the approximating language may correspond to the precision of an instrument for measuring the value. In the description and claims of the application, the range limitations may be combined and/or interchanged, if not otherwise specified, including all the sub-ranges subsumed therein. Furthermore, the indefinite articles "a" and "an" preceding an element or component of the application are not limited to the requirements of the number of elements or components (i.e. the number of occurrences). Thus, the use of "a" or "an" should be interpreted as including one or at least one, and the singular reference of an element or component also includes the plural reference unless the amount clearly dictates otherwise.
The technical scheme of the application can solve the problem that the service temperature of the lead-free high-temperature solder after welding is insufficient relative to the welding temperature, develops the high-temperature lead-free micro-metallurgical solder, can realize lead-free welding under the high-temperature condition, and has reliable temperature cycling load capacity.
In embodiments of the present application, the following various alloy powders are referred to.
The alloy powder A1 is Sn-Ag-Cu alloy; the mass ratio of each component in the Sn-Ag-Cu alloy is Sn96.5%, ag3% and Cu0.5%. Alloy powder A1 has a melting point of 217-219 ℃.
The alloy powder A2 is Sn-Ag-Cu alloy; the mass ratio of each component in the Sn-Ag-Cu alloy is 99 percent of Sn, 0.3 percent of Ag0.7 percent of Cu. Alloy a powder 2 melting point 227 ℃.
The alloy powder A3 is an Sn-Sb alloy, and the mass ratio of each component in the alloy is Sn:95% of Sb 5%. Alloy powder A3 has a melting point of 235-240 ℃.
The alloy powder A4 is Sn-Sb alloy, and the mass ratio of each component in the alloy is Sn:90% of Sb and 10%. Alloy powder A4 has a melting point of 240-245 ℃.
The alloy powder A is Sn-Sb alloy, and the mass ratio of each component in the alloy is Sn:89.5%, sb 10%, ni:0.5%. Alloy powder A has a melting point of 247-253 ℃.
The B alloy powder 1 is Sn-Sb-Ag-Cu alloy, and the mass ratio of each component in the alloy is Sn:37 percent, 49.4 percent of Sb and 13.6 percent of Ag; alloy powder B has a melting point of 369-390 ℃.
The alloy powder 2 is Sn-Sb-Ag-Cu alloy, and the mass ratio of each component in the alloy is Sn:42% of Sb 40%, 12% of Ag and 6% of Cu; alloy powder B has a melting point of 332-356 ℃.
The B alloy powder 3 is Sn-Sb-Ag-Cu alloy, and the mass ratio of each component in the alloy is Sn:41 percent of Sb, 35 percent of Ag, 15 percent of Ag, 6 percent of Cu and 3 percent of Bi. Alloy powder B3 has a melting point of 331-349 ℃.
The mass percentage of Sn, sb, ag, cu in the B alloy satisfies the relation:
a=1.4633b+0.366c+1.5538d+e, wherein a is Sn mass percent, b is Sb mass percent, c is Ag mass percent, d is Cu mass percent, and e is-0.4-0.2, preferably-0.3-0.2. The alloy components in the proportion ensure that the melting point of the alloy B is proper, provide enough intermetallic compounds for the high-temperature lead-free welding spots of the micro-metallurgy and provide a material basis for the micro-metallurgy. The e value is less than-0.4, sn atoms are relatively less, the melting point is increased, the hardness of the alloy is increased, and the wettability and the ductility are insufficient. The e value is more than-0.2, sn atoms are relatively more, a low-melting-point phase is easy to appear, and the temperature resistance of welding spots is reduced.
The C alloy powder 2 is Sn-Sb alloy, and the mass ratio of each component in the alloy is Sn:90% of Sb and 10%. The melting point of the C alloy powder 2 is 240-245 ℃.
The C alloy powder 1 is Sn-Sb alloy, and the mass ratio of each component in the alloy is Sn:89.5%, sb 10%, ni:0.5%. The melting point of the C alloy powder 1 is 247-253 ℃.
The D metal powder 1 is Ag. D metal powder 1 melting point 961 DEG C
The D metal powder 2 is Cu. D metal powder 2 melting point 1083 DEG C
The D metal powder 3 is Fe. D metal powder 3 melting point 1535 ℃.
The D metal powder 4 is Co. D metal powder 4 melting point 1495 ℃.
The metal powder D5 is silver-coated copper AgCu, the mass ratio of the components is Ag 10-30%, cu 70-90% and the melting point is more than 900 ℃.
As in fig. 1, ten different embodiments are shown, each of which is described in detail below. In each example, the a alloy powder, the B alloy powder, the C alloy powder, and the D metal powder were each separately prepared powders. The solder paste prepared by the components of each embodiment is welded by adopting a welding temperature curve shown in fig. 4 or 5, and shear force experiments under different temperature loads are carried out on welded welding spots, wherein the experimental condition is that an R0603 resistor device is attached to a copper bonding pad, and an electric heating plate is heated in a stepped manner. R0603 device shear force, R0603 device shear force data at 250 ℃ were tested at room temperature. Shear force data is shown in fig. 2; fig. 3 is a bar graph of the data of fig. 2. It can be seen that the embodiments of the present application are better in terms of both the welding reliability at normal temperature and the reliability at high temperature, and improved uniformity is obtained.
High temperature solder example 1: comprising an A alloy powder 1 and a B alloy powder 2; the mass ratio of the alloy powder A1 is 10%; the mass ratio of the B alloy powder 2 was 90%. The temperature interval range set in the micro-metallurgical welding stage is 280-360 ℃; the micro-metallurgical stage holding time was 180 seconds.
High temperature solder example 2: comprising an A alloy powder 1 and a B alloy powder 2; the mass ratio of the alloy powder A1 is 20%; the mass ratio of the B alloy powder 2 was 80%. The temperature interval range set in the micro-metallurgical welding stage is 280-360 ℃; the micro-metallurgical stage holding time was 200 seconds.
High temperature solder example 3: comprising an A alloy powder 1 and a B alloy powder 2; the mass ratio of the alloy powder A1 is 30%; the mass ratio of the B alloy powder 2 was 70%. The temperature interval range set in the micro-metallurgical welding stage is 280-360 ℃; the micro-metallurgical stage holding time was 240 seconds.
High temperature solder example 4: comprising an A alloy powder 2 and a B alloy powder 3; the mass ratio of the alloy powder A2 is 15%; the mass ratio of the B alloy powder 3 was 85%. The temperature interval set in the micro-metallurgical welding stage is 280-350 deg.c; the micro-metallurgical stage holding time was 200 seconds.
High temperature solder example 5: comprising an A alloy powder 4 and a B alloy powder 3; the mass ratio of the alloy powder A4 is 20 percent, and the mass ratio of the alloy powder B3 is 80 percent. The temperature interval set in the micro-metallurgical welding stage is 280-350 deg.c; the micro-metallurgical stage holding time was 180 seconds.
High temperature solder example 6: comprising an A alloy powder 5 and a B alloy powder 1; the mass ratio of the alloy powder A5 is 15%, and the mass ratio of the alloy powder B1 is 85%. The temperature interval range set in the micro-metallurgical welding stage is 280-360 ℃; the micro-metallurgical stage holding time was 150 seconds.
High temperature solder example 6: comprising an A alloy powder 5 and a B alloy powder 1; the mass ratio of the alloy powder A1 is 15%, and the mass ratio of the alloy powder B2 is 85%. The temperature interval range set in the micro-metallurgical welding stage is 280-360 ℃; the micro-metallurgical stage holding time was 150 seconds.
High temperature solder example 7: comprises an A alloy powder 1, a C alloy powder 1 and a B alloy powder 2; the mass ratio of the alloy powder A is 10%, the mass ratio of the alloy powder C is 10%, and the mass ratio of the alloy powder B is 80%. The temperature interval set in the micro-metallurgical welding stage is 280-350 deg.c; the micro-metallurgical stage holding time was 160 seconds.
High temperature solder example 8: comprises an A alloy powder 1, a C alloy powder 2, a B alloy powder 1 and a B alloy powder 1; the mass ratio of the alloy powder A to the alloy powder B is 15%, the mass ratio of the alloy powder C to the alloy powder C is 15%, and the mass ratio of the alloy powder A to the alloy powder B to the alloy powder C is 70%. The temperature interval set in the micro-metallurgical welding stage is 280-345 ℃; the micro-metallurgical stage holding time was 120 seconds.
High temperature solder example 9: comprises an A alloy powder 1, a B alloy powder 2 and a D metal powder 1; the mass ratio of the alloy powder A is 14%, the mass ratio of the alloy powder B is 85%, and the mass ratio of the metal powder D is 1%. The temperature interval set in the micro-metallurgical welding stage is 280-350 deg.c; the micro-metallurgical stage holding time was 180 seconds.
High temperature solder example 10: comprising an A alloy powder 6, a B alloy powder 2 and a D metal powder 3; the mass ratio of the alloy powder A to the alloy powder B is 20%, the mass ratio of the alloy powder B to the alloy powder 2 is 79%, and the mass ratio of the alloy powder D to the metal powder 3 is 1%. The temperature interval range set in the micro-metallurgical welding stage is 280-340 ℃; the micro-metallurgical stage holding time was 180 seconds.
High temperature solder example 11: comprising an A alloy powder 6, a B alloy powder 3 and a D metal powder 2; the mass ratio of the alloy powder A to the alloy powder B is 18%, the mass ratio of the alloy powder B to the alloy powder 3 is 80%, and the mass ratio of the alloy powder D to the metal powder 2 is 2%. The temperature interval set in the micro-metallurgical welding stage is 280-345 ℃; the micro-metallurgical stage holding time was 120 seconds.
High temperature solder example 12: comprising an A alloy powder 4, a B alloy powder 3 and a D metal powder 3; the mass ratio of the alloy powder A4 is 14.9%, the mass ratio of the alloy powder B3 is 85%, and the mass ratio of the metal powder D3 is 0.1%. The temperature interval set in the micro-metallurgical welding stage is 280-345 ℃; the micro-metallurgical stage holding time was 120 seconds.
High temperature solder example 13: comprising an A alloy powder 4, a B alloy powder 3 and a D metal powder 4; the mass ratio of the alloy powder A4 is 14.9%, the mass ratio of the alloy powder B3 is 85%, and the mass ratio of the metal powder D4 is 0.1%. The temperature interval set in the micro-metallurgical welding stage is 280-345 ℃; the micro-metallurgical stage holding time was 120 seconds.
To illustrate the technical effect, a comparative example was designed to perform a control experiment, and experimental data are shown in the table of fig. 1.
Comparative example 1: comprises an A alloy powder 1, a C alloy powder 2 and a B alloy powder 2; the mass ratio of the alloy powder A1 is 10%; the mass ratio of the C alloy powder 2 is 10%; the mass ratio of the B alloy powder 2 was 80%. The temperature interval range set in the welding stage is 280-350 ℃; the holding time was shortened to 30 seconds.
Comparative example 2: comprises an A alloy powder 1, a C alloy powder 2 and a B alloy powder 2; the mass ratio of the alloy powder A1 is 10%; the mass ratio of the C alloy powder 2 is 10%; the mass ratio of the B alloy powder 2 was 80%. The temperature range set in the welding stage is increased to 280-370 ℃; the holding time was 80 seconds.
Comparative example 3: comprising an a alloy powder 6; the mass ratio of the A alloy powder 6 is 100%. The temperature interval range set in the welding stage is 280-285 ℃; the weld stage hold time was 40 seconds.
Comparative example 4: comprising a B alloy powder 2; the mass ratio of the B alloy powder 2 was 100%. The temperature interval range set in the welding stage is 280-380 ℃; the holding time was 30 seconds.
In comparative example 5, the alloy comprises a high lead 925 alloy, wherein the mass ratio of each component in the alloy is Sn:5 percent of Pb 92.5 percent and Ag 2.5 percent. The temperature range set in the reflow soldering stage is 280-340 ℃; the reflow soldering phase hold time was 40 seconds.
Comparative example 6 includes a commercial transient liquid phase solder; the mass ratio of the transient liquid phase solder is 100%. The temperature interval range set in the welding stage is 300-320 ℃; the stage hold time was 150 seconds.
As shown in fig. 4, a lead-free micro-metallurgical welding method for high-temperature welding is based on the micro-metallurgical packaged solder composition of example 1, wherein a welding temperature curve is completed in three sections, namely a heating-up stage, a micro-metallurgical welding stage and a cooling-down stage; the temperature interval range of the micro-metallurgical temperature setting in the micro-metallurgical welding stage is 280-360 ℃; the maintenance time of the micro-metallurgy stage is 120-240 seconds; micro-metallurgical packaging solder a micro-metallurgical process occurs during soldering. The temperature of the heating stage is raised from 25 ℃ to 280 ℃, the heating rate is 3 ℃/s to 6 ℃/s, and the heating time is 45 s to 90 s; the temperature in the cooling stage is cooled from 350 ℃ to 80 ℃ at a cooling rate of 3-8 ℃/s.
As shown in fig. 5, a lead-free micro-metallurgical welding method for high-temperature welding is based on the micro-metallurgical packaged solder composition of example 4, wherein the welding temperature curve is completed in three sections, namely a heating-up stage, a micro-metallurgical welding stage and a cooling-down stage; the temperature interval range of the micro-metallurgical temperature setting in the micro-metallurgical welding stage is 280-350 ℃; the maintenance time of the micro-metallurgy stage is 120-240 seconds; micro-metallurgical packaging solder a micro-metallurgical process occurs during soldering.
As shown in fig. 6 and 7, SEM (scanning electron microscope Scanning Electron Microscope, SEM) and EDS (Spectrometer EDS, energy Dispersive Spectrometer) are used to analyze the elemental type and content of the micro-area component of the material based on the micro-metallurgical solder after reflow of example 4. As can be clearly seen in fig. 6 and 7, the intermetallic compound is distributed at the pad interface and within the filler matrix, and the final intermetallic compound Cu 3 Sn has formed at the solder-to-pad interface on the Cu pad side and more Cu 6Sn5,Sn3Sb2,Cu3 Sn intermetallic compound has formed on the solder side. Different intermetallic compounds such as Cu 6Sn5,Sn3Sb2,Ag3 Sn and SnSb matrix + beta-Sn have been formed from metal powders of different melting points in the solder matrix. Sb atoms are dissolved in beta-Sn in a solid mode to cause lattice distortion, the resistance to dislocation movement is increased, and a solid solution strengthening effect is generated, so that the bonding strength of a micro-metallurgical welding spot is improved, a large amount of intermetallic compounds are dispersed in a matrix, the dispersed Bi-rich spots improve the phase change growth of the intermetallic compounds, the generation of rod-shaped Ag 3 Sn is reduced to form a spot-shaped structure, the rapid growth of Cu 6Sn5 is inhibited, a net-shaped structure is formed, and the welding spot alloy is strengthened. The low-melting-point metal powder preferentially reacts with the intermetallic compound of the bonding pad, the existence of the intermetallic compound at the interface consumes the low-melting-point beta-Sn phase, and the high-temperature bearing capacity of the micro-metallurgical welding spot is ensured by the micro-metallurgical bonding of the high-melting-point matrix of the micro-metallurgical welding flux. Meanwhile, the dispersed Bi-rich structure can absorb creep stress of the welding spot, so that the welding spot has stronger creep resistance and thermal fatigue resistance.
After the high-temperature lead-free micro-metallurgical solder is welded, the packaged device is subjected to four times of reflow in a reflow oven at the packaging temperature of 260 ℃, and slice SEM+EDS analysis is carried out on the solder, as shown in fig. 8 and 9, after the reflow at the temperature of 260 ℃ for a plurality of times, the intermetallic compound at the interface is not obviously increased, which indicates that the beta-Sn content in the micro-metallurgical solder joint matrix is insufficient, and the high-temperature service reliability of the solder joint is ensured.
The welding spot alloy obtained by the implementation of the technology comprises Sn-Sb-Ag-Cu alloy, wherein the mass ratio of each component in the alloy is Sn:37% -42%, sb 28% -44%, ag:8% -13%, 0% -7% of Cu, bi:0% -3%. And 0 to 0.1% of other metals including any one or more of Ni, fe, co, mn, ce, au.
And the mass percentage of Sn, sb, ag, cu in the welding spot alloy satisfies the relation: a=1.4633b+0.366c+1.558d+e, wherein a is Sn in mass percent, b is Sb in mass percent, c is Ag in mass percent, d is Cu in mass percent, and e is-0.3-0. The alloy components in the proportion ensure that the melting point of the lead-free high-temperature soldering spot of the micro metallurgy is proper, and the alloy can bear the reflow peak temperature of 260-280 ℃ for a plurality of times and can be used for a long time at high temperature. The alloy proportion provides enough intermetallic compound for the micro-metallurgy high-temperature lead-free welding spot and is a necessary condition for the later-stage high-temperature service of the micro-metallurgy welding spot. The e value is less than-0.3, the Sn atoms are relatively less, the alloy hardness is higher, the wettability is insufficient, and the creep resistance is poor. The e value is more than 0, sn atoms are relatively more, and a low-melting-point phase can appear on a welding spot to influence the high-temperature service performance. The Sn content in the appointed range is proper, and can be kept under the alloy component conditions required by micro-smelting welding, so that a high-temperature lead-free welding spot with high reliability is finally formed.
In the prior art, in the process of preparing the solder, after the welding temperature requirement is determined, the multi-element alloy design is carried out, and after the multi-element alloy design is completed, various single-element metals forming the multi-element alloy are jointly melted to form alloy powder for final welding, so that the concept is reliable, and the conventional solder can be designed.
However, in some special application scenarios, there is a special soldering temperature requirement, such as a high soldering temperature, but it is desirable to withstand a higher soldering temperature after soldering. Particularly, the high-temperature solder needs to withstand high temperature during welding, and in high-temperature reflow soldering, in order to achieve the melting temperature of the welding spot, such as 340-360 ℃, the temperature setting of the welding equipment is usually higher, such as 390-410 ℃, so that higher requirements are put on the service temperature of the welded welding spot after welding. How to solve the problems of obviously improving the welding temperature and improving the service temperature after welding, and provides new challenges for welding materials. Because the temperature at the time of welding is relatively low and the temperature to be tolerated after welding is high, which is a pair of contradictions, the melting point of the alloy formed after melting of the alloy at the welding temperature is generally fixed relative to the welding temperature after the alloy design is completed. The highest service temperature that it tolerates is therefore limited to the melting point of the alloy.
The application discards a simple method for common melting of all alloys, breaks through the conventional thinking, and designs the multi-alloy-component solder with the stepped melting point by utilizing the characteristics of the alloys. The multi-alloy component solder with the stepped melting point comprises at least two alloy powders which are respectively prepared, the welding process is controlled, the melting point difference of the two alloys is utilized, the advantages of each alloy are exerted, in the welding process, besides the conventional melting process for forming a new alloy, the micro-metallurgical process of coexistence of liquid molten alloy and solid alloy also occurs, in addition, the temperature control is combined in the process, the time of the micro-metallurgical process is reasonably controlled, not only is the atomic diffusion carried out on the solder and a bonding pad carried out, but also the atomic diffusion is carried out between the metal powders with different melting points between the solder, a large amount of intermetallic compounds are produced, the connection reliability of welding positions is further improved, and the high Wen Fuyi capacity of the solder is improved.
The alloys with different melting points are respectively and independently prepared into powder, and then the powder of the different alloys is mixed together according to the set component ratio to be used as the medium-temperature lead-free micro-metallurgical solder; as the melting point temperature difference of different alloys is large enough, the solder is matched with the specific micro-metallurgical welding temperature and time in the welding process, and the formed welding spot contains a large amount of intermetallic compounds, so that grains are refined, the grain growth speed of the welding spot in the service process is prevented, the dislocation movement resistance among the grains is increased, the packaging strength of the welding spot is increased, and the reliability of the welding spot is improved.
The micro-metallurgical packaging solder contains metal powder with different melting points, in the heating process, the relatively low-melting-point alloy powder A or C is melted first, the relatively high-melting-point alloy powder B or D is still solid, the medium-temperature metal melt is connected with high-temperature metal particles to form a structure similar to human muscle and skeleton, so that the collapse resistance of the solder is improved, the collapse resistance is particularly important in the narrow-interval high-density packaging of the microelectronic integrated circuit, and the risk of tin connection short circuit is reduced.
The micro-metallurgical packaging solder contains relatively low-melting-point A alloy powder and relatively high-melting-point B alloy powder, so that the reflow soldering process can be completed at the packaging temperature not higher than the melting point of the B alloy, the B alloy is corroded by the metal atoms of the A alloy, the atoms of the B alloy occupy or replace part of the atoms in the A alloy, the solid solution strengthening of the enhanced elements is achieved, and the generated intermetallic compound achieves the purpose of precipitation strengthening. And finally welding to form a multi-element alloy welding spot. Compared with the traditional solder paste, the creep resistance and aging resistance reliability of the welding spot can be greatly improved. Not only reduces the packaging welding temperature, saves energy consumption, and is environment-friendly.
The micro-metallurgical packaging solder contains B alloy powder and D metal powder with relatively high melting points, and in the micro-metallurgical process, the A alloy powder and the B alloy powder are arranged between the B alloy powder and the C alloy powder; the micro-metallurgical process can be generated between the A alloy powder and the D metal powder, between the B alloy powder and the D metal powder and between the C alloy powder and the D metal powder due to enough melting point difference, and atomic diffusion bonding can be generated between metal atoms of different components to generate a large amount of intermetallic compounds, so that intermetallic compounds with higher melting points are formed, and the structure is firmer.
And the time for micro-metallurgical welding is controlled to be at least 120 seconds, so that enough time is provided for the process, the coexistence time between the liquid molten alloy and the solid alloy or metal is long enough, the micro-metallurgical process can be more fully completed, and the application of medium-temperature encapsulation and high-temperature service of the welding piece can be realized. The micro-metallurgy high-temperature solder can realize the breakthrough of technical bottlenecks of high-temperature lead-free solders in the industry, find a new application mode of the high-temperature lead-free solder, and can replace the high-lead solder.
The combination of the alloy with multiple components strengthens the micro-metallurgical process, and the atomic diffusion bonding is more sufficient and has more abundant layers, so that the final welding strength is higher.
Solder pastes based on micro-metallurgically encapsulated solders are essentially different compared to conventional solder paste products. The micro-metallurgy packaging solder in the application has a micro-metallurgy process in the welding process, not only the solder and the bonding pad are subjected to atomic diffusion to produce intermetallic compounds, but also metal powder with different melting points among the solders are subjected to atomic diffusion to produce a large amount of intermetallic compounds.
The micro-metallurgical packaging solder has simple preparation and application process, high production efficiency and good application value. The micro-metallurgical packaging solder changes the design thought of the traditional solder, and the research and development of the traditional solder is generally to design alloy, wherein all metals are metallurgically melted together to form alloy, comprehensively powder preparation, solder paste alloy powder preparation, secondary melting and solidification to form a fixed alloy welding spot. The micro-metallurgical packaging solder is used as a basic metal alloy design, alloys with different melting points are respectively subjected to alloy metallurgical melting, respectively powder preparation, different alloy powder mixing, solder paste preparation, solder melting and solder spot micro-metallurgical process, and solidification to form a new alloy solder spot. The component design is matched with specific micro-metallurgical welding temperature and time, and the micro-metallurgical process occurs in the process of forming the welding spots, so that a large amount of intermetallic compounds are generated, and the packaging strength and the tolerant temperature of the welding spots can be increased.
The foregoing description is only exemplary embodiments of the present application, and is not intended to limit the scope of the present application, and all equivalent structures or equivalent processes using the contents of the specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present application.
Claims (17)
1. A high-temperature lead-free micro-metallurgical solder is characterized in that,
Comprises an A alloy powder and a B alloy powder;
the difference between the melting point of the alloy A and the melting point of the alloy B is 70-150 ℃;
The mass ratio of the alloy powder A is 30-10%, and the mass ratio of the alloy powder B is 70-90%.
2. A high temperature lead-free micro-metallurgical solder according to claim 1, wherein,
The A alloy comprises Sn-Ag-Cu alloy; the Sn-Ag-Cu alloy comprises the following components in percentage by mass: 95.5% -99%, ag:0.3% -3.8%, cu:0.5% -0.7%.
3. A high temperature lead-free micro-metallurgical solder according to claim 1, wherein,
The alloy A comprises an Sn-Sb alloy, wherein the mass ratio of each component in the alloy is Sn:89.5 to 95 percent of Sb, 5 to 10 percent of Ni:0% -0.5%.
4. A high temperature lead-free micro-metallurgical solder according to claim 1, wherein,
The B alloy comprises Sn-Sb-Ag-Cu alloy, and the mass ratio of each component in the alloy is Sn:37% -42%, sb 35% -50%, ag:12% -15%, cu 0% -6%, bi:0% -3%;
and the mass percentage of Sn, sb, ag, cu in the B alloy satisfies the relation:
a=1.4633b+0.366c+1.558d+e, wherein a is Sn mass percent, b is Sb mass percent, c is Ag mass percent, d is Cu mass percent, and e is in a range of-0.4-0.2.
5. The high temperature lead-free micro-metallurgical solder of claim 1, wherein,
Also comprises C alloy powder;
The C alloy comprises Sn-Sb alloy, wherein the mass ratio of each component in the alloy is Sn:89.5 to 95 percent of Sb, 5 to 10 percent of Ni:0% -0.5%;
The mass ratio of the alloy powder A is 25-5%, the mass ratio of the alloy powder B is 70-90%, and the mass ratio of the alloy powder C is 25-5%.
6. A high temperature lead-free micro-metallurgical solder according to claim 5, wherein,
The particle size of the alloy powder A is 1-50 mu m;
the particle size of the alloy powder B is 1-50 mu m;
The particle size of the C alloy powder is 1-50 mu m.
7. The high temperature lead-free micro-metallurgical solder of claim 1, wherein,
The micro-nano D metal powder is also included;
the melting point temperature of the micro-nano D metal is more than 400 ℃;
The mass ratio of the alloy powder A is 10-27%, the mass ratio of the alloy powder B is 70-87%, and the mass ratio of the metal powder D is 0.1-3%.
8. The high temperature lead-free micro-metallurgical solder of claim 7, wherein,
The method is characterized by comprising any one of the following technical characteristics:
characteristic TC1: the metal D is Ag;
characteristic TC2: the metal D is Cu;
characteristic TC3: the metal D is Fe;
characteristic TC4: the metal D is Ce;
characteristic TC5: the metal D is Ni;
characteristic TC6: the metal D is Co;
characteristic TC7: the metal D is Mn;
Characteristic TC8: the metal D is silver-coated copper AgCu, and the mass ratio of the components is 10-30% of Ag and 70-90% of Cu.
9. A high temperature lead-free micro-metallurgical solder according to claim 7, wherein,
The particle size of the alloy powder A is 1-50 mu m;
the particle size of the alloy powder B is 1-50 mu m;
The size of the micro-nano D metal powder is 100 nm-10 mu m.
10. A high-temperature lead-free micro-metallurgical tin paste is characterized in that,
Comprising the high temperature lead-free micro-metallurgical solder of any one of claims 1 to 9.
11. A preparation method for high-temperature lead-free micro-metallurgical solder is characterized in that,
Preparing alloy powder A and alloy powder B separately;
the difference between the melting point of the alloy A and the melting point of the alloy B is 70-150 ℃;
mixing the alloy powder A and the alloy powder B to form micro-metallurgical welding powder;
The mass ratio of the alloy powder A is 10-30%, and the mass ratio of the alloy powder B is 70-90%.
12. The method for preparing high-temperature lead-free micro-metallurgical solder according to claim 11, wherein,
Preparing C alloy powder independently;
mixing the alloy powder A, the alloy powder B and the alloy powder C to form micro-metallurgical welding powder;
The mass ratio of the alloy powder A is 25-5%, the mass ratio of the alloy powder B is 70-90%, and the mass ratio of the alloy powder C is 25-5%.
13. The method for preparing high-temperature lead-free micro-metallurgical solder according to claim 11, wherein,
Separately preparing micro-nano D metal powder, wherein the melting point temperature of the micro-nano D metal is more than 400 ℃; the size of the micro-nano D metal powder is 100 nm-10 mu m;
Mixing the alloy powder A, the alloy powder B and the metal powder D to form micro-metallurgical welding powder;
The mass ratio of the alloy powder A is 10-27%, the mass ratio of the alloy powder B is 70-87%, and the mass ratio of the metal powder D is 0.1-3%.
14. The method for producing a high-temperature lead-free micro-metallurgical solder according to any one of claims 11 to 13, wherein,
Based on the micro-metallurgical welding powder, adding soldering flux or soldering flux matched with the micro-metallurgical welding powder, and stirring the mixture into micro-metallurgical solder paste and solder paste.
15. A high-temperature lead-free micro-metallurgical welding method is characterized in that,
Based on the high temperature lead-free micro-metallurgical solder according to any of the preceding claims 1 to 9,
Or based on the high-temperature lead-free micro-metallurgical tin paste as claimed in claim 10
The welding temperature curve is completed in three sections, namely a heating stage, a micro-metallurgical welding stage and a cooling stage;
The temperature interval range of the micro-metallurgical temperature setting in the micro-metallurgical welding stage is 280-350 ℃;
The maintenance time of the micro-metallurgy stage is 120-240 seconds;
Micro-metallurgical packaging solder a micro-metallurgical process occurs during soldering.
16. The high-temperature lead-free micro-metallurgical welding method according to claim 15, wherein,
The temperature of the heating stage is raised from 25 ℃ to 280 ℃, the heating rate is 3 ℃/s to 6 ℃/s, and the heating time is 45 s to 90 s;
The temperature in the cooling stage is cooled from 350 ℃ to 80 ℃ at a cooling rate of 3-8 ℃/s.
17. A welding spot formed by high-temperature lead-free micro-metallurgical welding is characterized in that,
The welding spot comprises Sn-Sb-Ag-Cu alloy, wherein the mass ratio of each component in the alloy is Sn:37% -42%, sb 28% -44%, ag:8% -13%, 0% -7% of Cu, bi:0% -3% and 0% -0.1% of other metals, wherein the other metals comprise any one or more of Ni, fe, co, mn, ce, au;
The mass percent of Sn, sb, ag, cu in the welding spot alloy satisfies the relation:
a=1.4633b+0.366c+1.558d+e, wherein a is Sn in mass percent, b is Sb in mass percent, c is Ag in mass percent, d is Cu in mass percent, and e is-0.3-0.
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