WO2016178000A1 - Alliage de soudure sans plomb à bas point de fusion - Google Patents

Alliage de soudure sans plomb à bas point de fusion Download PDF

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Publication number
WO2016178000A1
WO2016178000A1 PCT/GB2016/051218 GB2016051218W WO2016178000A1 WO 2016178000 A1 WO2016178000 A1 WO 2016178000A1 GB 2016051218 W GB2016051218 W GB 2016051218W WO 2016178000 A1 WO2016178000 A1 WO 2016178000A1
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WO
WIPO (PCT)
Prior art keywords
alloy
solder
copper
bismuth
germanium
Prior art date
Application number
PCT/GB2016/051218
Other languages
English (en)
Inventor
Morgana DE AVILA RIBAS
Suresh TELU
Anil Kumar
Pritha CHOUDHURY
Ranjit Pandher
Siuli Sarkar
Bawa Singh
Original Assignee
Alpha Metals, Inc.
SETNA, Rohan
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Alpha Metals, Inc., SETNA, Rohan filed Critical Alpha Metals, Inc.
Publication of WO2016178000A1 publication Critical patent/WO2016178000A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/24—Selection of soldering or welding materials proper
    • B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400 degrees C
    • B23K35/262—Sn as the principal constituent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
    • B23K35/0222—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in soldering, brazing
    • B23K35/0233—Sheets, foils
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
    • B23K35/0222—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in soldering, brazing
    • B23K35/0244—Powders, particles or spheres; Preforms made therefrom
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
    • B23K35/0222—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in soldering, brazing
    • B23K35/0244—Powders, particles or spheres; Preforms made therefrom
    • B23K35/025—Pastes, creams, slurries
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/20—Layered products comprising a layer of metal comprising aluminium or copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
    • B32B3/02—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by features of form at particular places, e.g. in edge regions
    • B32B3/08—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by features of form at particular places, e.g. in edge regions characterised by added members at particular parts
    • B32B3/085—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by features of form at particular places, e.g. in edge regions characterised by added members at particular parts spaced apart pieces on the surface of a layer
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    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/05—Interconnection of layers the layers not being connected over the whole surface, e.g. discontinuous connection or patterned connection
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C13/00—Alloys based on tin
    • C22C13/02—Alloys based on tin with antimony or bismuth as the next major constituent
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
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    • H05K3/3457—Solder materials or compositions; Methods of application thereof
    • H05K3/3463—Solder compositions in relation to features of the printed circuit board or the mounting process
    • 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
    • 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
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    • B32B2250/00—Layers arrangement
    • B32B2250/02—2 layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
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    • H01L23/498—Leads, i.e. metallisations or lead-frames on insulating substrates, e.g. chip carriers
    • H01L23/49811—Additional leads joined to the metallisation on the insulating substrate, e.g. pins, bumps, wires, flat leads
    • H01L23/49816—Spherical bumps on the substrate for external connection, e.g. ball grid arrays [BGA]
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    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
    • H05K2201/10613—Details of electrical connections of non-printed components, e.g. special leads
    • H05K2201/10621—Components characterised by their electrical contacts
    • H05K2201/10734—Ball grid array [BGA]; Bump grid array
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    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
    • H05K3/341—Surface mounted components
    • H05K3/3431—Leadless components
    • H05K3/3436—Leadless components having an array of bottom contacts, e.g. pad grid array or ball grid array components

Definitions

  • the present invention relates generally to the field of metallurgy and to an alloy and, in particular, a lead-free solder alloy.
  • the alloy is particularly, though not exclusively, suitable for use in electronic soldering applications such as wave soldering, surface mounting technology, hot air leveling and ball grid arrays, land grid arrays, bottom terminated packages, LEDs and chip scale packages.
  • Wave soldering is a widely used method of mass soldering electronic assemblies. It may be used, for example, for through-hole circuit boards, where the board is passed over a wave of molten solder, which laps against the bottom of the board to wet the metal surfaces to be joined.
  • Another soldering technique involves printing of the solder paste on the soldering pads on the printed circuit boards followed by placement and sending the whole assembly through a reflow oven. During the reflow process, the solder melts and wets the soldering surfaces on the boards as well as the components.
  • Another soldering process involves immersing printed wiring boards into molten solder in order to coat the copper terminations with a solderable protective layer. This process is known as hot-air leveling.
  • a ball grid array joint or chip scale package is assembled typically with spheres of solder between two substrates. Arrays of these joints are used to mount chips on circuit boards.
  • soldering materials As use of lead-free soldering materials becomes widespread, either due to environmental directives or pressure from the end users, so does the range of applications for such materials.
  • High Ag solder alloys such as SnAg3.0Cu0.5, have the benefits of excellent mechanical properties and good thermal reliability.
  • the melting point of such alloys is about 217-221 °C. This higher melting point requires reflow temperature of about 240-250 °C, which may in certain cases be damaging to the printed circuit boards (PCBs) and electronic components.
  • PCBs printed circuit boards
  • electronic assembly there is usually more than one step in soldering. In reflow soldering some joints have to go through a reflow cycle more than once.
  • the first formed joint is formed using a relatively high melting temperature solder and a lower melting temperature solder is used to make subsequent joints. This ensures that first formed joints do not re-melt during secondary or ternary reflow cycles.
  • solders have totally different metallurgical compositions. In most of the cases where these two types of solders do not come in contact with each other there is no problem.
  • the first solder used in BGA bumping comes into contact with the second type of solder used in the solder paste used for BGA component attachment on the board. In such cases the alloys mix up during the second reflow and the composition and properties of the final interconnect could be different.
  • the present invention aims to solve at least some of the problems associated with the prior art or to provide a commercially acceptable alternative.
  • the present invention provides a lead-free solder alloy comprising:
  • germanium from 0.001 to 1 wt.% germanium
  • gallium up to 3 wt.% gallium
  • the alloy may exhibit particularly favourable mechanical properties, and may be advantageously used, for example, in a ball grid array or flip chip assembly process.
  • the present invention will now be further described. In the following passages different aspects of the invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.
  • solder alloy used herein encompasses a fusible metal alloy with a melting point in the range of from 90 to 400 °C.
  • rare earth element used herein encompasses an element selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.
  • flip chip as used herein encompasses a chip used in a method for interconnecting semiconductor devices, such as IC chips and
  • MEMS microelectromechanical systems
  • external circuitry e.g. a circuit board or another chip or wafer
  • it is flipped over so that its top side faces down, and aligned so that its pads align with matching pads on the external circuit, and then the solder is reflowed to complete the interconnect.
  • wire bonding in which the chip is mounted upright and wires are used to interconnect the chip pads to external circuitry.
  • ball grid array refers to a package with one face covered (or partly covered) with pads in a grid pattern, each initially having a ball of solder stuck to it.
  • the pads conduct electrical signals between the integrated circuit and the printed circuit board (PCB) on which it is placed.
  • the solder spheres can be placed manually or by automated equipment, and are held in place with a tacky flux.
  • the device is placed on a PCB with copper pads in a pattern that matches the solder balls.
  • the assembly is then heated, either in a reflow oven or by an infrared heater, melting the balls. Surface tension causes the molten solder to hold the package in alignment with the circuit board, at the correct separation distance, while the solder cools and solidifies, forming soldered connections between the device and the PCB.
  • flux encompasses a substance, often an acid or base, used to promote fusing of metals and in particular to remove and prevent the formation of metal oxides.
  • solidus encompasses the temperature below which a given substance is completely solid (crystallised). The solidus quantifies the temperature at which melting of a substance begins, but is not necessarily melted completely, i.e. the solidus is not necessarily a melting point.
  • liquidus encompasses the maximum temperature at which crystals can co-exist with molten substance. Above the liquidus
  • the material is homogeneous and liquid at equilibrium. Below the liquidus temperature more and more crystals may form.
  • the solidus and liquidus temperatures do not align or overlap in all cases. If a gap exists between the solidus and liquidus temperatures it is called the “freezing range” or “mush range”, and within that gap the substance consists of a mixture of solid and liquid phases.
  • the lead-free solder alloys described herein may exhibit favourable mechanical properties and mechanical reliability.
  • the mechanical properties, mechanical reliability and thermal reliability may be similar to, or more favourable than, that of the eutectic or non-eutectic Sn-Bi and Sn-ln alloys.
  • the alloys may exhibit improved thermal shock performance compared with the eutectic Sn-Bi and Sn-ln alloys.
  • the alloys may exhibit a low temperature melting range. The use of low
  • temperature solder alloys may reduce energy costs, allow for the use of low temperature compatible components, and/or improve assembly of temperature- sensitive applications.
  • the alloys may exhibit a low liquidus temperature, typically less than 210 °C, more typically less than 205 °C. This may enable the alloy to be used to mount lower temperature components in a secondary reflow process, for example at 220-230 °C. In this regard, the alloys typically exhibit a liquidus temperature of at least 140 °C, more typically at least 150 °C, evenmore typically at least 170 °C.
  • the alloys may advantageously be used in a soldering method employing multiple reflow processes on a single board. For example, in a first reflow process, all electronic components that can tolerate higher reflow temperatures could be soldered to a board using standard alloys such as, for example,
  • temperature sensitive components could be processed using the alloys of the present invention.
  • some electronic components could be soldered using the alloys of the present invention, and, in a second reflow process, the remaining components would be processed using alloys with lower liquidus and solidus temperatures.
  • the alloys typically exhibit a wide solidus-liquidus melting range (so-called “pasty range”).
  • the temperature range between solidus and liquidus may be at least 30 °C.
  • the alloys may be advantageously used as the solder spheres of a ball grid array (BGA).
  • BGA ball grid array
  • use of the alloys may avoid or reduce the problem of sphere collapse during a BGA assembly process.
  • the secondary reflow typically carried out at a temperature of 175 °C or less (e.g from 160 to 175 or 170 °C)
  • the solder spheres will not melt completely, thereby reducing or eliminating the problem of sphere collapse (i.e. leading to higher standoff).
  • the spheres With a significant fraction of the sphere alloys remaining in solid form during the secondary reflow, the spheres will be slow to mix with the paste alloy. Accordingly, the problem of the final interconnect exhibiting unfavorable, unintended properties may also be reduced or eliminated.
  • the alloys may advantageously exhibit a slow and gradual freezing over a relatively long time. This may enable the alloy to move and settle before the freezing point. Accordingly, the occurrence of localised stress points in the final interconnects will be reduced.
  • the alloys are lead-free meaning that no lead is added intentionally. Thus, the lead contents are zero or at no more than accidental impurity levels.
  • the alloy comprises from 20 to 35 wt.% bismuth.
  • the alloy comprises from 21 to 31 wt.% bismuth, more preferably from 21 to 26 wt.% bismuth, even more preferably from 21 .5 to 25.5 wt.% bismuth.
  • the alloy comprises from 21 .5 to 22.5 wt.% bismuth, for example about 22 wt.%.
  • the alloy comprises from 22.5 to 23.5 wt.% bismuth, for example about 23 wt.%.
  • the alloy comprises from 20 to 35 wt.% bismuth.
  • the alloy comprises from 21 to 31 wt.% bismuth, more preferably from 21 to 26 wt.% bismuth, even more preferably from 21 .5 to 25.5 wt.% bismuth.
  • the alloy comprises from 21 .5 to 22.5 wt.% bismuth, for example about 22 wt.%.
  • the alloy comprises from 22.5 to 23.5 wt.%
  • the alloy comprises from 24.5 to 25.5 wt.% bismuth, for example about 25 wt.%. In an alternative preferred embodiment, the alloy comprises from 29.5 to 30.5 wt.% bismuth, for example about 30 wt.%. The presence of bismuth in the specified amount may serve to reduce the melting point of the alloy.
  • the alloy comprises from 0.01 to 10 wt.% copper.
  • the alloy comprises from 0.1 to 3 wt.% copper, more preferably from 0.1 to 2.5 wt.% copper, even more preferably from 0.1 to 1 .5 wt.% copper, still even more preferably from 0.15 to 0.5 wt.% copper, still even more preferably from 0.18 to 0.3 wt.% copper.
  • the alloy comprises from 0.15 to 0.25 wt.% copper.
  • the alloy comprises from 0.8 to 1 .2 wt.% copper.
  • the alloy comprises from 1 .8 to 2.2 wt.% copper.
  • the presence of copper in the specified amount may serve to improve mechanical properties, for example strength, through the formation of intermetallic compounds.
  • the presence of copper reduces copper dissolution and may also improve creep resistance.
  • the solder alloy comprises one or more of
  • germanium from 0.001 to 1 wt.% germanium
  • the alloy comprises one of these elements. In an alternative preferred embodiment, the alloy comprises two of these elements. In a preferred embodiment, the alloy comprises germanium and one or more of the elements, preferably one of these elements. The alloy preferably comprises germanium and cobalt, or germanium and manganese, or germanium and nickel. The alloy may comprise from 0.001 to 4 wt.% antimony. Preferably, the alloy comprises from 1 to 3 wt.% antimony, more preferably from 1 .5 to 2.5 wt.% antimony, even more preferably from, 1 .8 to 2.2 wt.% antimony, still even more preferably about 2 wt.% antimony. Antimony may serve as a deoxidiser.
  • Antimony may serve to improve strength, interfacial reactions and creep resistance.
  • the alloy may comprise from 0.001 to 1 wt.% cobalt.
  • the alloy comprises from 0.01 to 0.5 wt.% cobalt, more preferably from 0.01 to 0.1 wt.% cobalt, even more preferably from 0.01 to 0.08 wt.% cobalt, still even more preferably from 0.02 to 0.04 wt.% cobalt, still even more preferably from 0.025 to 0.035 wt.% cobalt, still even more preferably about 0.03 wt.% cobalt.
  • Cobalt may slow the rate of IMC formation at the substrate / solder interface, and increase drop-shock resistance.
  • the alloy may comprise from 0.001 to 1 wt.% germanium.
  • the alloy comprises from 0.001 to 0.1 wt.% germanium, more preferably from 0.001 to 0.01 wt.% germanium, even more preferably from 0.002 to 0.008 wt.% germanium, still even more preferably from 0.003 to 0.007 wt.% germanium, still even more preferably more preferably from 0.004 to 0.006 wt.% germanium, still even more preferably about 0.005 wt.% germanium.
  • the presence of germanium in the specified amount may serve to improve strength and interfacial reactions.
  • Germanium may also serve as a deoxidiser. Germanium may improve wettability and spread.
  • the alloy may comprise from 0.001 to 1 wt.% manganese.
  • the alloy comprises from 0.005 to 0.1 wt.% manganese, more preferably from 0.005 to 0.02 wt.% manganese, even more preferably from 0.008 to 0.012 wt.%
  • manganese still even more preferably from 0.009 to 0.01 1 wt.% manganese, still even more preferably about 0.01 wt.% manganese.
  • the presence of manganese in the specified amount may serve to improve strength, interfacial reactions and creep resistance. Manganese may also improve drop shock and thermal cycling reliability.
  • the alloy may comprise from 0.001 to 1 wt.% nickel.
  • the alloy comprises from 0.01 to 0.1 wt.% nickel, more preferably from 0.02 to 0.08 wt.% nickel, even more preferably from 0.025 to 0.035 wt.% nickel, still even more preferably from 0.028 to 0.032 wt.% nickel, still even more preferably about 0.03 wt.% nickel.
  • the presence of nickel in the specified amount may serve to improve mechanical properties through the formation of intermetallic compounds with tin, which can result in precipitation strengthening. Nickel may also increase drop shock resistance by decreasing IMC growth at the substrate/solder interface.
  • the alloy may comprise from 0.001 to 1 wt.% titanium.
  • the alloy comprises from 0.005 to 0.1 wt.% titanium, more preferably from 0.01 to 0.05 wt.% titanium.
  • the presence of titanium in the specified amount may serve to improve strength, interfacial reactions and creep resistance. Titanium may also improve drop shock performance by controlling copper diffusion at the substrate / solder interface.
  • the alloy optionally comprises up to 10 wt.% silver.
  • the alloy comprises up to 2 wt.% silver, more preferably from 0.1 to 1 .8 wt.% silver, even more preferably from 0.5 to 1 .5 wt.% silver, still even more preferably from 0.9 to 1 .1 wt.% silver, still even more preferably about 1 wt.% silver.
  • the presence of silver in the specified amount may serve to improve mechanical properties, for example strength, through the formation of intermetallic compounds.
  • the presence of silver may act to improve wetting, spread, creep resistance and thermal cycling reliability.
  • the alloy optionally comprises up to 3 wt.% indium.
  • the alloy comprises up to 1 wt.% indium, more preferably from 0.005 to 1 wt.% indium, even more preferably from 0.01 to 0.05 wt.%.
  • the presence of indium may act to improve mechanical properties through solid solution strengthening.
  • the presence of indium in the recited amounts, together with the other alloy elements, may also serve to reduce the liquidus temperature of the alloy.
  • the alloy optionally comprises up to 3 wt.% of gallium.
  • the alloy comprises up to 2 wt.% gallium, more preferably from 0.005 to 1 wt.% gallium, even more preferably from 0.01 to 0.05 wt.%.
  • gallium may act to improve mechanical properties through solid solution strengthening.
  • Gallium may also serve as a deoxidiser.
  • Gallium may improve wettability and spread.
  • the alloy may optionally contain one or more of up to 1 wt.% gold (e.g. 0.01 to 0.1 wt.%), up to 1 wt.% chromium (e.g. 0.01 to 0.1 wt.%), up to 1 wt.% zinc (e.g. 0.01 to 0.1 wt.%), up to 1 wt.% iron (e.g. 0.01 to 0.1 wt.%), up to 1 wt.% aluminium (e.g.
  • the alloy may optionally contain one or more of up to 1 wt.% phosphorus (e.g.
  • Such elements may serve as deoxidisers. The presence of such elements may improve wettability of the alloy.
  • the alloy may optionally contain up to 1 wt.% of rare earth element(s) (e.g. 0.01 to 0.1 wt.%). Rare earths may act to improve spread and wettability. Cerium has been found to be particularly effective in this regard.
  • the alloy will typically comprise at least 74 wt.% tin, more typically at least 80 wt.% tin, still more typically at least 85 wt.% tin.
  • the alloy comprises from 29 to 31 wt.% bismuth, from 1 .8 to 2.2 wt.% copper, from 1 .8 to 2.2 wt.% antimony, the balance Sn and any unavoidable impurities.
  • the alloy comprises from 24 to 26 wt.% bismuth, from 0.8 to 1 .2 wt.% copper, from 0.03 to 0.04 wt.% cobalt, from 0.003 to 0.007 wt.% germanium, the balance Sn and any unavoidable impurities.
  • the alloy comprises from 22 to 24 wt.% bismuth, from 0.15 to 0.25 wt.% copper, from 0.02 to 0.04 wt.% cobalt, from 0.003 to 0.007 wt.% germanium, the balance Sn and any unavoidable impurities.
  • the alloy comprises from 22 to 24 wt.% bismuth, from 0.15 to 0.25 wt.% copper, from 0.008 to 0.012 wt.% manganese, from 0.003 to 0.007 wt.% germanium, the balance Sn and any unavoidable impurities.
  • the alloy comprises from 24 to 26 wt.% bismuth, from 0.15 to 0.25 wt.% copper, from 0.02 to 0.04 wt.% nickel, from 0.003 to 0.007 wt.% germanium, the balance Sn and any unavoidable impurities.
  • the alloy comprises from 22 to 24 wt.% bismuth, from 0.15 to 0.25 wt.% copper, from 0.02 to 0.04 wt.% nickel, from 0.003 to 0.007 wt.% germanium, from 0.5 to 1 .5 wt.% silver, the balance Sn and any
  • the alloy comprises from 21 to 23 wt.% bismuth, from 0.15 to 0.25 wt.% copper, from 0.02 to 0.04 wt.% cobalt, from 0.003 to 0.007 wt.% germanium, from 0.5 to 1 .5 wt.% silver, the balance Sn and any
  • the alloy comprises from 21 to 23 wt.% bismuth, from 0.15 to 0.25 wt.% copper, from 0.005 to 0.02 wt.% manganese, from 0.003 to 0.007 wt.% germanium, the balance Sn and any unavoidable impurities.
  • the alloy comprises from 21 to 23 wt.% bismuth, from 0.15 to 0.25 wt.% copper, from 0.003 to 0.007 wt.% germanium, from 0.5 to 1 .5 wt.% silver, the balance Sn and any unavoidable impurities.
  • the solder alloy preferably has a liquidus temperature of 210 °C or less, more preferably 205 °C or less.
  • the difference between the solidus temperature and the liquidus temperature is preferably at least 30 °C, more preferably at Ieast50 °C.
  • the alloys described herein may contain unavoidable impurities, although, in total, these are unlikely to exceed 1 wt.% of the composition.
  • the alloys contain unavoidable impurities in an amount of not more than 0.5 wt.% of the composition, more preferably not more than 0.3 wt.% of the composition, still more preferably not more than 0.1 wt.% of the composition, still more preferably not more than 0.05 wt.% of the composition, and most preferably not more than 0.02 wt.% of the composition.
  • the alloys described herein may consist essentially of the recited elements. It will therefore be appreciated that in addition to those elements that are mandatory other non-specified elements may be present in the composition provided that the essential characteristics of the composition are not materially affected by their presence.
  • the alloys may be in the form of, for example, a bar, a stick, a solid or flux cored wire, a foil or strip, a film, a preform, or a powder or paste (powder plus flux blend), or solder spheres for use in ball grid array joints or chip scale packages, or other pre-formed solder pieces, with or without a flux core or a flux coating, or a reflowed or solidified solder joint, or pre-applied on any solderable material such as a copper ribbon.
  • the solder alloy is in the form of a paste.
  • the paste comprises particles of the solder alloy, typically a powder, dispersed in a flux.
  • the solder alloy is in the form of a preform.
  • a preform is a pre-made shape of solder specially designed for the application where it is to be used. Many methods may be used to manufacture the solder preform, for example stamping.
  • the preform may comprise flux.
  • the flux may be an internal flux insider the solder preform or and external flux coating the solder preform.
  • the present invention provides a solder joint comprising an alloy as described herein.
  • the present invention provides a ball grid array or chip scale packages having a solder bump thereon, the solder bump comprising the alloy as described herein.
  • the present invention provides a chip scale package having a solder bump thereon, the solder bump comprising the alloy as described herein.
  • the present invention provides a photovoltaic cell comprising the alloy described herein.
  • the present invention provides a solder paste comprising the alloy described herein and a flux.
  • the present invention provides a method of forming a solder joint comprising:
  • the present invention provides use of the alloy as described herein in a soldering method such as wave soldering, Surface Mount Technology (SMT) soldering, die attach soldering, thermal interface soldering, hand soldering, laser and RF induction soldering, soldering to a solar module, soldering of LED package boards, and rework soldering.
  • a soldering method such as wave soldering, Surface Mount Technology (SMT) soldering, die attach soldering, thermal interface soldering, hand soldering, laser and RF induction soldering, soldering to a solar module, soldering of LED package boards, and rework soldering.
  • SMT Surface Mount Technology
  • the present invention provides use of the alloy as described herein to increase standoff height in a solder joint of a ball grid array or chip scale package.
  • the solder joint is formed by reflow at a temperature below the liquidus temperature of the alloy to result in partial melting of the alloy.
  • the present invention provides a method of forming a solder joint between a circuit board and a solder bump of a ball grid array or flip chip or chip scale package, the method comprising:
  • solder bump comprising a first alloy, the first alloy being the alloy as described herein;
  • solder paste in the vicinity of the circuit board and the solder bump, the solder paste comprising a second alloy having a liquidus temperature lower than the liquidus temperature of the first alloy
  • the circuit board may be, for example, a printed circuit board (PCB).
  • the circuit board may form part of a photovoltaic cell.
  • the solder paste may be disposed manually or by using automated equipment.
  • the solder paste typically comprises a flux.
  • the solder paste is typically tacky so as to remain in its desired position.
  • the second alloy is typically in the form of a powder.
  • the heating is typically carried out at a temperature below the liquidus
  • temperature of the first alloy typically at a temperature of from 160 to 175 or 160 to 170 °C.
  • the heating may be carried out, for example, in a conventional reflow oven. Such ovens are known in the art. Suitable temperatures for the heating step are known in the art but may be, for example, 200 °C or less, 190 °C or less, 180 °C or less, 170 °C or less, 150 °C or less, - ⁇ 4VC or less, greater than 130 °C, or greater than 140 °C or greater than 150 °C.
  • the liquidus temperature of the second alloy may be at least 10 °C lower than that of the first alloy, preferably at least 20 °Clower.
  • the method may further comprise, for example, incorporating the circuit board into a photovoltaic cell.
  • the second alloy may comprise, for example, a SnBi alloy or SnBi with other alloying additions, such as, for example, Ag and/or Cu and/or Ni and/or Co and/or Mn and/or Ti.
  • the second alloy preferably comprises 42Sn-58Bi or other near eutectic Sn-Bi alloys that exhibit low melting temperature suitable for secondary or tertiary reflow for low temperature components.
  • the present invention provides a method of forming a solder joint between a circuit board and a solder bump of a ball grid array or flip chip or chip scale package, the method comprising:
  • solder bump comprising a first alloy
  • solder paste in the vicinity of the circuit board and the solder bump, the solder paste comprising a second alloy, the second alloy being the alloy as described herein;
  • the first alloy has a liquidus temperature higher than the liquidus temperature of the second alloy.
  • the heating may be carried out, for example, in a conventional reflow oven. Such ovens are known in the art. Suitable temperatures for the heating step are known in the art but may be, for example, 240 °C or less, 235 °C or less, 230 °C or less, 225 °C or less, 220 °C or less, greater than 200 °Cor greater than 210 °C.
  • the first alloy may have a liquidus temperature at least 10 °C higher than that of the second alloy, preferably at least 20 °C higher.
  • the first alloy preferably comprises Sn-3Ag-0.5Cu.
  • Sn-3Ag-0.5Cu alloy exhibits a high melting temperature and favourable mechanical properties suitable for primary reflow.
  • the first alloy comprises Sn-4Ag- 0.5Cu.
  • the first alloy comprises Sn-Ag or Sn-Cu or Sn-Ag-Cu alloy.
  • the present invention provides a lead-free solder alloy comprising:
  • the alloy exhibits similar advantages to the alloy of the first aspect.
  • the alloy may exhibit particularly favourable mechanical properties, and may be advantageously used, for example, in a ball grid array or chip scale package or flip chip assembly process.
  • the alloy may exhibit more favourable mechanical properties, for example higher hardness, in comparison to the alloy of the first aspect.
  • alloy of this aspect of the present invention may be used in the solder joint, ball grid array, chip scale package, photovoltaic cell, methods and uses as described above.
  • the alloy comprises from 8 to 12 wt.% bismuth.
  • the alloy comprises from 8.5 to 1 1 .5 wt.% bismuth, more preferably from 9 to 1 1 wt.% bismuth, even more preferably from 9.5 to 10.5 wt.% bismuth, still even more preferably about 10 wt.% bismuth.
  • the presence of bismuth in the specified amount may serve to reduce the melting point of the alloy.
  • Bismuth may also improve mechanical properties through solid solution strengthening.
  • Bismuth may also act to improve creep resistance.
  • Bismuth may also improve wetting and spread.
  • solder alloy comprises one or more of:
  • the solder alloy preferably comprises only one of indium, copper and silver.
  • the alloy may comprise copper and silver but no indium.
  • the alloy may comprise indium and silver but no copper.
  • the alloy may comprise indium and copper but no silver.
  • the alloy may comprise indium, copper and silver.
  • the alloy may comprise from 0.5 to 7 wt.% indium.
  • the alloy preferably
  • the alloy comprises from 1 to 6 wt.% indium, more preferably from 1 .5 to 3.5 wt.% indium.
  • the alloy may preferably comprise from 0.5 to 1 .5 wt.% indium, more preferably from 0.7 to 1 .2 wt.% indium.
  • the alloy preferably comprises from 1 .5 to 2.5 wt.% indium, more preferably from 1 .8 to 2.2 wt.% indium.
  • the alloy preferably comprises from 2.5 to 3.5 wt.% indium, more preferably from 2.8 to 3.2 wt.% indium.
  • the alloy preferably comprises from 5.5 to 6.5 wt.% indium, more preferably from 5.8 to 6.2 wt.% indium.
  • the presence of indium may act to improve mechanical properties through solid solution strengthening.
  • the presence of indium in the recited amounts, together with the other alloy elements, may also serve to reduce the liquidus temperature of the alloy.
  • the alloy may comprise from 0.1 to 1 .5 wt.% copper.
  • the alloy comprises from 0.2 to 1 .2 wt.% copper, more preferably from 0.3 to 1 wt.% copper.
  • the alloy may preferably comprise from 0.2 to 0.4 wt.% copper.
  • the alloy may preferably comprise from 0.4 to 0.6 wt.% copper.
  • the alloy may preferably comprise from 0.6 to 0.8 wt.% copper.
  • the alloy may preferably comprise from 0.8 to 1 .2 wt.% copper.
  • the presence of copper in the specified amount may serve to improve mechanical properties, for example strength, through the formation of intermetallic
  • the presence of copper reduces copper dissolution and may also improve creep resistance.
  • the alloy may comprise from 0.5 to 1 .5 wt.% silver.
  • the alloy comprises from 0.7 to 1 .3 wt.% silver, more preferably from 0.9 to 1 .1 wt.% silver.
  • the presence of silver in the specified amount may serve to improve mechanical properties, for example strength, through the formation of intermetallic
  • the presence of silver may act to improve wetting and spread.
  • the alloy optionally comprises up to 1 wt.% of cobalt, for example from 0.01 to 1 wt.%. If cobalt is present, the alloy preferably comprises from 0.005 to 0.1 wt.% cobalt, more preferably from 0.005 to 0.05 wt.% cobalt, even more preferably from 0.009 to 0.04 wt.% cobalt. Cobalt may slow the rate of IMC formation at the substrate / solder interface, and increase drop-shock resistance.
  • the alloy optionally comprises from up to 1 wt.% of nickel, for example from 0.01 to 1 wt.%.
  • the alloy preferably comprises from 0.01 to 0.1 wt.% nickel, more preferably from 0.01 to 0.05 wt.% nickel, even more preferably from 0.02 to 0.04 wt.% nickel.
  • the presence of nickel in the specified amount may serve to improve mechanical properties through the formation of
  • the alloy optionally comprises up to 1 wt.% of titanium, for example from 0.005 to 1 wt.%. If titanium is present, the alloy preferably comprises from 0.001 to 0.1 wt.% titanium, more preferably from 0.01 to 0.05 wt.% titanium, even more preferably from 0.02 to 0.04 wt.% titanium. The presence of titanium in the specified amount may serve to improve strength and interfacial reactions.
  • Titanium may also improve drop shock performance by controlling copper diffusion at the substrate / solder interface.
  • the alloy optionally comprises up to 1 wt.% of manganese, for example from 0.005 to 1 wt.%. If manganese is present, the alloy preferably comprises from 0.005 to 0.1 wt.% manganese, more preferably from 0.008 to 0.05 wt.%
  • manganese even more preferably from 0.009 to 0.03 wt.% manganese.
  • the presence of manganese in the specified amount may serve to improve strength and interfacial reactions. Manganese may also improve drop shock performance.
  • the alloy optionally comprises up to 1 wt.% of gallium, for example from 0.005 to 1 wt.%. If gallium is present, the alloy preferably comprises from 0.1 to 1 wt.% gallium, more preferably from 0.3 to 0.9 wt.% gallium, even more preferably from 0.5 to 0.7 wt.% gallium. The presence of gallium may act to improve mechanical properties through solid solution strengthening.
  • the alloy optionally comprises up to 1 wt.% of germanium, for example from 0.005 to 1 wt.%.
  • the alloy preferably comprises from 0.01 to 0.1 wt.% germanium, more preferably from 0.02 to 0.08 wt.% germanium, even more preferably from 0.03 to 0.07 wt.% germanium.
  • the presence of germanium in the specified amount may serve to improve strength and interfacial reactions.
  • Germanium may also serve as a deoxidiser. Germanium may improve wettability and spread.
  • the alloy may optionally contain one or more of up to 1 wt.% phosphorus (e.g. 0.01 to 0.1 wt.%), up to 1 wt.% aluminium (e.g. 0.01 to 0.1 wt.%), up to 1 wt.% calcium (e.g. 0.01 to 0.1 wt.%), up to 1 wt.% magnesium (e.g. 0.01 to 0.1 wt.%) and up to 1 wt.% vanadium (e.g. 0.01 to 0.1 wt.%).
  • Such elements may serve as deoxidisers. The presence of such elements may improve wettability of the alloy.
  • the alloy may optionally contain one or more of up to 1 wt.% gold (e.g.
  • Such elements may serve as deoxidisers. Such elements may serve to improve strength and interfacial reactions. The presence of zinc may act to improve mechanical properties through solid solution strengthening.
  • the alloy may optionally contain up to 1 wt.% of rare earth element(s) (e.g. 0.01 to 0.1 wt.%). Rare earths may act to improve spread and wettability. Cerium has been found to be particularly effective in this regard.
  • the alloy will typically comprise at least 74 wt.% tin, more typically at least 80 wt.% tin, still more typically at least 85 wt.% tin.
  • the alloy comprises from 9 to 1 1 wt.% bismuth and from 0.8 to 1 .2 wt.% copper, the balance tin together with any unavoidable impurities.
  • the alloy comprises from 9 to 1 1 wt.% bismuth, from 2.5 to 3.5 wt.% indium and from 0.01 to 0.05 wt.% cobalt, the balance tin together with any unavoidable impurities.
  • the alloy comprises from 9 to 1 1 wt.% bismuth, from 0.3 to 0.7 wt.% gallium and from 0.1 to 0.5 wt.% copper, the balance tin together with any unavoidable impurities.
  • the alloy comprises from 1 1 to 12 wt.% bismuth, from 0.8 to 1 .2 wt.% copper and from 0.01 to 0.05 wt.% cobalt, the balance tin together with any unavoidable impurities.
  • the alloy comprises from 8 to 9 wt.% bismuth, from 0.8 to 1 .2 wt.% copper and from 0.01 to 0.05 wt.% cobalt, the balance tin together with any unavoidable impurities.
  • the alloy comprises from 9 to 1 1 wt.% bismuth, from 2.5 to 2.5 wt.% indium and from 0.005 to 0.015 wt.% manganese, the balance tin together with any unavoidable impurities.
  • the alloy comprises from 9 to 1 1 wt.% bismuth, from 1 .5 to 2.5 wt.% indium, from 0.3 to 0.7 wt.% copper and from 0.01 to 0.05 wt.% cobalt, the balance tin together with any unavoidable impurities.
  • the alloy comprises from 8 to 9 wt.% bismuth, from 2.5 to 3.5 wt.% indium, from 0.1 to 0.5 wt.% copper and from 0.01 to 0.05 wt.% cobalt, the balance tin together with any unavoidable impurities.
  • the alloy comprises from 9 to 1 1 wt.% bismuth, from 5.5 to 6.5 wt.% indium and from 0.4 to 0.8 wt.% gallium, the balance tin together with any unavoidable impurities.
  • the alloy comprises from 9 to 1 1 wt.% bismuth, from 0.5 to 0.9 wt.% copper, from 0.7 to 1 .1 wt.% indium and from 0.005 to 0.015 wt.% cobalt, the balance tin together with any unavoidable impurities.
  • the solder alloy preferably has a liquidus temperature of 220 °C or less, more preferably 215 °C or less.
  • the present invention provides an alloy comprising 10 to 30 %wt Bi, one or more of Ag, Au, Cr, In, P, Cu, Zn, Co, Ge, Mn, Ni, Ti, Ga, Fe, Sb, Al, Te, Se, Ca, V, Mo, Pt, Mg, rare earths and the balance Sn, together with any unavoidable impurities.
  • the alloy comprises 10 to 30 %wt Bi, one or more of 0.01 to 10% Ag, 0.01 to 10% Cu, 0.001 to 1 wt% Co, 0.001 to 1 wt% Ni, and 0.001 to 3 wt% In, 0.001 to 4 wt% Sb, 0.001 to 1 wt% Ti, 0.001 to 3 wt% Ga, 0.001 to 1 wt% Mn, 0.001 to 1 wt% Ge, 0.001 to 1 wt% Zn, 0.001 to 1 wt% Fe, 0.001 to 1 wt% Au, 0.001 to 1 wt% Cr, 0.001 to 1 wt% P, 0.001 to 1 wt% Al, 0.001 to 1 wt% Te, 0.001 to 1 wt% Se, 0.001 to 1 wt% Ca, 0.001 to 1 wt% V, 0.001 to 1 wt% Mo, 0.001 to 1 wt% P
  • the present invention provides an alloy comprising 10 to 30 %wt In, one or more of Ag, Au, Cr, In, P, Cu, Zn, Co, Ge, Mn, Ni, Ti, Ga, Fe, Sb, Al, Te, Se, Ca, V, Mo, Pt, Mg, rare earths and the balance Sn, together with any unavoidable impurities.
  • the alloy comprises 10 to 30 %wt In, one or more of 0.01 to 10% Ag, 0.01 to 10% Cu, 0.001 to 1 wt% Co, 0.001 to 1 wt% Ni, and 0.001 to 3 wt% Bi, 0.001 to 4 wt% Sb, 0.001 to 1 wt% Ti, 0.001 to 3 wt% Ga, 0.001 to 1 wt% Mn, 0.001 to 1 wt% Ge, 0.001 to 1 wt% Zn, 0.001 to 1 wt% Fe, 0.001 to 1 wt% Au, 0.001 to 1 wt% Cr, 0.001 to 1 wt% P, 0.001 to 1 wt% Al, 0.001 to 1 wt% Te, 0.001 to 1 wt% Se, 0.001 to 1 wt% Ca, 0.001 to 1 wt% V, 0.001 to 1 wt% Mo, 0.001 to 1 wt% Pt
  • Figure 1 shows a schematic of a BGA attached to a circuit board showing low standoff.
  • Figure 2 shows a schematic of a BGA attached to a circuit board showing high standoff.
  • Figure 3 shows a plot of hardness (Hv-0.5) of example alloys according to the present invention and comparative examples.
  • FIG. 1 there is shown a schematic of a BGA component 1 attached to a circuit board 2.
  • the conventional solder 3 forming the BGA bumping (spheres) is the same as the solder 4 used to attach the circuit board 2 to the BGA component 1 .
  • the conventional solder 3, 4 exhibits low standoff 5 due to complete collapse of the spheres during secondary reflow. Such a low standoff assembly results in high sheer stress experienced at the solder-pad interfaces.
  • FIG 2 there is shown a schematic of a BGA component 6 attached to a circuit board 7.
  • the solder 8 forming the BGA bumping is according to the present invention and the solder 9 used to attach the circuit board 7 to the BGA component 6 is a conventional SnBi eutectic solder.
  • solders 8, 9 exhibit high standoff 10, since a significant fraction of the solder 8 of the present invention remains in solid form during the secondary reflow. As a result, it is slow to mix with the conventional solder 9. Such a high standoff assembly reduces the shear stress experienced at the solder-pad interface.
  • Table 1 Solidus temperature, liquidus temperature and solid fraction at various temperatures. ( * Comparative Examples.) As per the Sn-Bi phase diagram, there is a eutectic alloy composition with 58 wt.% bismuth and 42 wt.% tin, which has a melting point around 138 °C.
  • Reducing the bismuth content increases the liquidus temperature of this alloy. For example, reducing the bismuth content to 25 wt.% (Comparative Example 2) results in a liquidus temperature of 207 °C, which makes this alloy a good candidate for secondary reflow. However, if the bismuth content decreases further, for example to 20 wt.% (Comparative Example 1 ), its liquidus
  • the solidus temperature is between 133 and 136 °C, with small variations due to the alloy additions.
  • the same examples show that higher liquidus temperatures will ensure a higher standoff (exemplified here by the solid fraction at 165 and 175 °C).
  • the higher SDlids fraction of the examples according to the present invention in comparison to the Sn-25Bi alloy results in better solder joints for the purpose stated above.
  • Vicker's hardness testing Hv-0.5 was carried out on some of the alloys of Table 1 and the results are shown in Figure 3. It can be seen that in comparison to the Sn-25Bi alloy (Comparative Example 2), the addition of alloying elements resulted in an increase in hardness. Examples 13-23
  • Table 2 Solidus temperature, liquidus temperature and solid fraction at 185 °C.
  • Table 2 shows that further reduction of Bi content, to about 15 wt.% or below, moves the Sn-Bi composition in the phase diagram such that the solidus temperature increases above 145 °C, which is benefbial for the thermo- mechanical properties (e.g. drop shock resistance and thermal cycling performance) of this alloy.
  • bismuth content below about 10 wt.% results in a liquidus temperature above 215 °C, which may render the alloy less appropriate for use in secondary reflow in assemblies where Sn-Ag-Cu alloys were used in the primary reflow.
  • small additions of Ga and In reduce its liquidus temperature within acceptable levels for secondary reflow.
  • Figure 3 shows that reduction of Bi content, and small additions of In and Ga increase the hardness of the alloys. For example, comparing examples 15 and 22, there is a 25 % increase in hardness, which, without being bound by theory, is considered to mostly result from 6 wt.% indium addition. Additionally, the solid fraction at 185 °C increases from 1 to 19 % between Example 15 and Example 22, which will result in better solder joints for the purpose stated above.

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Abstract

La présente invention concerne un alliage de soudure sans plomb comprenant de 20 à 35 % enpoids de bismuth, de 0,01 à 10 % en poids de cuivre, un ou plusieurs parmi : de 0 001 à 4 % enpoids d'antimoine, de 0 001 à 50 %en poids de cobalt, de 0 001 à 1 % enpoids de germanium, de 0 001 à 1 % enpoids de manganèse, 0.001 à 1 % enpoids de nickel, de 0 001 à 1 % enpoids de titane, optionnellement un ou plusieurs parmi : jusqu'à 3 % enpoids d'indium; jusqu'à 10% en poids d'argent; jusqu'à 3% en poids de gallium; jusqu'à 1% en poids d'or; jusqu'à 1% en poids de chrome; jusqu'à 1% en poids de phosphore; jusqu'à 1% en poids de zinc; jusqu'à 1% en poids de fer; jusqu'à 1% en poids d'aluminium; jusqu'à 1% en poids de tellure; jusqu'à 1% en poids de sélénium; jusqu'à 1% en poids de calcium; jusqu'à 1% en poids de vanadium; jusqu'à 1% en poids de molybdène; jusqu'à % en poids de platine; jusqu'à 1% en poids de magnésium; jusqu'à 1% en poids de terres rares, le reste étant Sn et des impuretés inévitables.
PCT/GB2016/051218 2015-05-02 2016-04-28 Alliage de soudure sans plomb à bas point de fusion WO2016178000A1 (fr)

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CN106624434A (zh) * 2016-11-30 2017-05-10 安徽华众焊业有限公司 锡锑焊料合金
CN106624433A (zh) * 2016-11-30 2017-05-10 安徽华众焊业有限公司 低熔点无铅焊料合金
CN106676322A (zh) * 2017-01-11 2017-05-17 同济大学 一种环境友好型硫族锡化物热电材料及其制备方法
CN106695162A (zh) * 2016-12-29 2017-05-24 安徽华众焊业有限公司 一种用于微电子行业的无铅焊料及其制备方法
CN108393608A (zh) * 2018-02-13 2018-08-14 西安泰力松新材料股份有限公司 一种光伏焊带用无铅合金焊料及其制备方法
CN108526748A (zh) * 2018-03-28 2018-09-14 云南锡业锡材有限公司 一种SnBiAgSbIn低温无铅焊料合金
KR20180106397A (ko) * 2017-03-20 2018-10-01 주식회사 휘닉스소재 저융점 무연 합금 솔더 조성물, 이를 포함하는 무연 솔더 페이스트 및 반도체 패키지
WO2020047481A1 (fr) * 2018-08-31 2020-03-05 Indium Corporation Alliages de brasage snbi et snin
WO2020083529A1 (fr) * 2018-10-24 2020-04-30 Alpha Assembly Solutions Inc. Solutions de brasage à basse température pour substrats polymères, cartes de circuits imprimés et autres applications d'assemblage
CN112404791A (zh) * 2020-11-18 2021-02-26 昆明理工大学 一种锡锌系无铅焊料合金及其制备方法
CN112440030A (zh) * 2020-12-04 2021-03-05 太仓巨仁光伏材料有限公司 一种用于异质结低温焊带的无铅焊料及熔炼炉
FR3101561A1 (fr) * 2019-10-06 2021-04-09 Jean-Claude Lucien Pruvost Alliage de soudure sans plomb appelé SIA à base de Sn et Bi et d’additifs de Cu et d’Ag limités à 1 %.
CN113042935A (zh) * 2021-05-20 2021-06-29 江苏德誉环保设备科技有限公司 一种无铅锡银铜钎焊用钎料的制备方法
CN113182728A (zh) * 2021-04-29 2021-07-30 烟台固邦新材料有限公司 一种可焊接铝的低熔点焊锡材料及其制备方法
CN114131238A (zh) * 2021-11-29 2022-03-04 常州时创能源股份有限公司 一种光伏焊带用钎料合金及其制备方法和应用
CN114850725A (zh) * 2022-05-24 2022-08-05 雅拓莱焊接科技（惠州）有限公司 超薄锡铋系预成型焊环及其制备工艺
TWI819210B (zh) * 2019-04-11 2023-10-21 日商日本斯倍利亞股份有限公司 無鉛焊錫合金及焊錫接合部
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CN106624433A (zh) * 2016-11-30 2017-05-10 安徽华众焊业有限公司 低熔点无铅焊料合金
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KR101951813B1 (ko) * 2017-03-20 2019-02-25 주식회사 휘닉스소재 저융점 무연 합금 솔더 조성물, 이를 포함하는 무연 솔더 페이스트 및 반도체 패키지
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CN108393608B (zh) * 2018-02-13 2020-12-01 西安泰力松新材料股份有限公司 一种光伏焊带用无铅合金焊料及其制备方法
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EP3778107B1 (fr) * 2018-03-30 2024-05-08 Senju Metal Industry Co., Ltd Pâte à souder
WO2020047481A1 (fr) * 2018-08-31 2020-03-05 Indium Corporation Alliages de brasage snbi et snin
WO2020083529A1 (fr) * 2018-10-24 2020-04-30 Alpha Assembly Solutions Inc. Solutions de brasage à basse température pour substrats polymères, cartes de circuits imprimés et autres applications d'assemblage
TWI819210B (zh) * 2019-04-11 2023-10-21 日商日本斯倍利亞股份有限公司 無鉛焊錫合金及焊錫接合部
US11999018B2 (en) 2019-08-30 2024-06-04 Indium Corporation SnBi and SnIn solder alloys
FR3101561A1 (fr) * 2019-10-06 2021-04-09 Jean-Claude Lucien Pruvost Alliage de soudure sans plomb appelé SIA à base de Sn et Bi et d’additifs de Cu et d’Ag limités à 1 %.
US11908784B2 (en) 2020-09-23 2024-02-20 Nxp Usa, Inc. Packaged semiconductor device assembly
CN112404791A (zh) * 2020-11-18 2021-02-26 昆明理工大学 一种锡锌系无铅焊料合金及其制备方法
CN112440030B (zh) * 2020-12-04 2023-08-22 太仓巨仁光伏材料有限公司 一种用于异质结低温焊带的无铅焊料及熔炼炉
CN112440030A (zh) * 2020-12-04 2021-03-05 太仓巨仁光伏材料有限公司 一种用于异质结低温焊带的无铅焊料及熔炼炉
US11830746B2 (en) 2021-01-05 2023-11-28 Taiwan Semiconductor Manufacturing Co., Ltd. Semiconductor device and method of manufacture
CN113182728A (zh) * 2021-04-29 2021-07-30 烟台固邦新材料有限公司 一种可焊接铝的低熔点焊锡材料及其制备方法
CN113042935A (zh) * 2021-05-20 2021-06-29 江苏德誉环保设备科技有限公司 一种无铅锡银铜钎焊用钎料的制备方法
CN114131238A (zh) * 2021-11-29 2022-03-04 常州时创能源股份有限公司 一种光伏焊带用钎料合金及其制备方法和应用
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