US20050100474A1 - Anti-tombstoning lead free alloys for surface mount reflow soldering - Google Patents

Anti-tombstoning lead free alloys for surface mount reflow soldering Download PDF

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US20050100474A1
US20050100474A1 US10/935,118 US93511804A US2005100474A1 US 20050100474 A1 US20050100474 A1 US 20050100474A1 US 93511804 A US93511804 A US 93511804A US 2005100474 A1 US2005100474 A1 US 2005100474A1
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alloy
tombstoning
weight
solder
lead
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US10/935,118
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Benlih Huang
Ning-Cheng Lee
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Indium Corp of America Inc
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Priority to US10/935,118 priority Critical patent/US20050100474A1/en
Assigned to INDIUM CORPORATION OF AMERICA reassignment INDIUM CORPORATION OF AMERICA ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HUANG, BENLIH, LEE, NING-CHENG
Priority to CN2004800318841A priority patent/CN101072886B/zh
Priority to EP04810184A priority patent/EP1685586A4/fr
Priority to PCT/US2004/036256 priority patent/WO2005048303A2/fr
Publication of US20050100474A1 publication Critical patent/US20050100474A1/en
Priority to US12/576,123 priority patent/US20100116376A1/en
Abandoned legal-status Critical Current

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    • 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
    • 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
    • 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
    • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
    • 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
    • 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
    • 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
    • H05K2201/10636—Leadless chip, e.g. chip capacitor or resistor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present disclosure relates generally to lead free alloys for use in soldering and, more particularly, to anti-tombstoning alloy compositions comprising tin, silver and copper.
  • tombstoning defects are one of the most common defects observed in surface mount reflow soldering of small leadless components such as resistors and capacitors are caused by a tombstoning effect (also known as the Manhattan effect, Drawbridge effect, and Stonehenge effect). This is a phenomenon in which a chip component is detached from the printed circuit board at one end while remaining bonded to the circuit board at the other end, whereby the chip component rises up toward a vertical position.
  • the tombstoning effect is attributed to the imbalance of a pulling force caused by surface tension of molten solders at both ends of a component during reflow soldering.
  • the intricate balance of the surface tension of the molten solder on the component may be easily disturbed by either the change of the solderability of the component or by differences in melting at the moment solder paste at each end of the component begins to reflow.
  • Taguchi et al. teaches using a solder powder alloy consisting of 60-65% tin (Sn), 0.1-0.6% silver (Ag), 0.1-2% antimony (Sb), and a balance of lead (Pb), to prevent tombstoning during reflow soldering.
  • Sn tin
  • Ag 0.1-0.6% silver
  • Sb antimony
  • Pb lead
  • Taguchi essentially employs Ag and Sb to effectively increase the solidification temperature range and, in turn, to prevent tombstoning.
  • an anti-tombstoning solder comprising of 32.0-42.0% (Pb), 58.0-68.0% (Sn), and 0.1-0.7% (Ag) to provide a wider solidification range and balance the surface tension of the molten solder.
  • solder alloys minimize tombstoning frequency, they contain lead.
  • Lead is known to have toxic effects and poses environmental and public health risks. For this reason, federal legislation has imposed strict limitations upon the use of lead and lead-containing compositions. Therefore, in recent times, replacing the tin-lead containing solders with lead-free solders has become a global trend in the electronics industries.
  • the preferred lead-free solders are tin-silver-copper alloys.
  • JEIDA Japan Electronic Industry Development Association
  • JEIDA Japan Electronic Industry Development Association
  • Sn—Ag—Cu alloys consist of Ag (4.0-3.0) %, Cu (1-0.5)%, balanced with Sn, which are largely covered by the patents of Anderson et al. (U.S. Pat. No. 5,527,628) and Tanabe et al. (Japanese patent No. 05-050286), except the Sn95.5Ag4Cu0.5 alloy published by Beghardt et al. (E Berghardt and G. Petrow, “Ueber den everyday des Systems Silber-Kupfer-Zinn”, Zeitschrift fuer Metallischen, 50, 1959, pp.
  • Lead-free Sn—Ag—Cu solder alloy compositions acceptable and usable in reflow soldering are disclosed.
  • a lead-free anti-tombstoning solder alloy comprises tin, silver and copper, which exhibits greater than 20% mass fraction of solid during melting.
  • the heat of absorption peak width, ⁇ T, during melting of the anti-tombstoning alloy is greater than 8° C. on a DSC (Differential Scanning Calorimetry) scan rate of 5° C./min.
  • the constituent metals comprise from about 1% to about 4.5% by weight of silver, from about 0.3% to 1% by weight of copper balanced with tin.
  • the constituent metals comprise from about 4% to about 2% by weight of silver, from about 0.5% to about 1% by weight of copper balanced with tin.
  • the constituent metals comprise from about 3.8% to about 2.5% by weight of silver, from about 0.5% to about 1% by weight of copper balanced with tin.
  • the alloy compositions may include a mechanical property improving element.
  • the mechanical property improving element comprises at least one or more element selected from the group consisting of Sb, Cu, Ni, Co, Fe, Mn, Cr and Mo in a total amount of at most 1 weight % of the solder alloy.
  • the alloy may include a melting temperature lowering element.
  • the temperature lowering element comprises at least one or more element selected from the group consisting Bi, In and Zn in a total amount of at most 3 weight % of the solder alloy.
  • the alloy may include an oxidation resistance improving element.
  • the oxidation resistance improving element comprises at least one or more element selected from the group consisting of P, Ga and Ge in a total amount of at most 0.5 weight % of the solder alloy.
  • a process of reflow soldering in electronic assemblies using various lead-free anti-tombstoning Sn—Ag—Cu solder alloy compositions is also disclosed.
  • the process of reducing tombstoning effect during reflow soldering in electronic assemblies comprises the usage of an anti-tombstoning solder in said assemblies, wherein said solder comprises 1% to about 4.5% by weight of silver, from about 0.3% to 1% by weight of copper balanced with tin.
  • the lead-free anti-tombstoning solder alloy comprises from about 4% to about 2% by weight of silver, from about 0.5% to about 1% by weight of copper balanced with tin.
  • the lead-free anti-tombstoning solder alloy comprises from about 3.8% to about 2.5% by weight of silver, from about 0.5% to about 1% by weight of copper balanced with tin.
  • the lead-free anti-tombstoning alloy may include a mechanical property improving element.
  • the mechanical property improving element comprises at least or more element selected from the group consisting of Sb, Cu, Ni, Co, Fe, Mn, Cr and Mo in a total amount of at most 1 weight % of the solder alloy.
  • the led-free anti-tombstoning solder alloy may include a melting temperature lowering element.
  • the melting temperature lowering element comprises at least one or more element selected from the group consisting of Bi, In and Zn in a total amount of at most 3 weight % of the solder alloy.
  • the led-free anti-tombstoning alloy may include an oxidation resistance improving element.
  • the oxidation resistance improving element comprises at least one or more element selected from the group consisting of P, Ga and Ge in a total amount of at most 0.5 weight % of the solder alloy.
  • FIG. 1 is a DSC (differential scanning calorimetry) curve of the Sn95.5Ag3.8Cu0.7 alloy composition in accordance with an embodiment of the present disclosure.
  • FIG. 2 is a DSC curve of the Sn 95.5Ag3.5Cu1 alloy composition in accordance with an embodiment of the present disclosure.
  • FIG. 3 is a DSC curve of the Sn 95.5Ag3.8Cu0.7 alloy composition in accordance with an embodiment of the present disclosure.
  • FIG. 4 is a DSC curve of the Sn 96.7Ag2.5Cu0.8 alloy composition in accordance with an embodiment of the present disclosure.
  • FIG. 5 is a DSC curve of the Sn 97.5Ag2Cu0.5 alloy composition in accordance with an embodiment of the present disclosure.
  • FIG. 6 is a DSC curve of the Sn 98.3Ag0.96Cu0.74 alloy composition in accordance with an embodiment of the present disclosure.
  • FIG. 7 is a DSC curve of the Sn 96.5Ag3.5Cu1 with estimated mass fraction of 64% in accordance with an embodiment of the present disclosure.
  • FIG. 8 illustrates the bar chart of the tombstoning frequency of the various Sn—Ag—Cu alloy compositions of the present disclosure.
  • the present disclosure is directed toward lead-free anti-tombstoning solder alloys comprising tin, silver and copper which exhibit the following properties:
  • solder alloy compositions were developed possessing the above cited properties for reducing the tombstoning frequency in accordance with the present disclosure.
  • the term “lead free” means that the alloy or solder does not contain lead or is essentially free of lead.
  • essentially free of lead see Federal Specification QQ-S571E Interim Amendment 5 (ER) 28 Dec. 1989, paragraph 3.2.1.1.1, as approved by the Commissioner, Federal supply service, General Services Administration (lead should not exceed 0.2%).
  • FIGS. 1-6 there are shown the DSC curves of the various Sn—Ag—Cu alloy compositions in accordance with several embodiments of the present disclosure.
  • FIG. 1 is a DSC curve for a Sn95.5Ag3.8Cu0.7 lead free solder alloy. It begins melting at 217° C., a large peak of heat absorption (endothermic peak) appears at 219° C. and melting is entirely completed at 223° C.
  • FIG. 2 is a DSC curve for a Sn95.5Ag3.5Cu1 lead free solder alloy. It begins melting at 217° C., a large peak of heat absorption appears at 218° C., and melting is entirely completed at 222° C.
  • FIG. 3 is a DSC curve for a Sn96.5Ag3Cu0.5 lead free solder alloy. It begins melting at 217° C., a large peak of heat absorption appears at 218.6° C., a second shoulder peak appears at 221° C., and melting is entirely completed at 223.5° C.
  • FIG. 4 is a DSC curve for a Sn96.7Ag2.5Cu0.8 lead free solder alloy. It begins melting at 216.5° C., a large peak of heat absorption appears at 219.5° C., and a shoulder absorption peak appears at 221.2° C., and melting is completed at 225° C.
  • FIG. 5 is a DSC curve for a Sn97.5Ag2Cu0.5 lead free solder alloy. It begins melting at 216.5° C., a first large peak of heat absorption appears at 218.2° C., a second large peak of heat absorption occurs at 219.5° C., and a small peak appears at 223.5° C., and melting is completed at 225° C.
  • FIG. 6 is a DSC curve for a Sn98.3Ag0.96Cu0.74 lead free solder alloy. It begins melting at 216° C., a large peak of heat absorption appears at 217.7° C., a second large peak appears at 218.8° C., a third large peak appears at 224.5° C., a shoulder peak appears at 225.4° C., and melting is completed at 228° C.
  • FIGS. 1-2 represent single peak alloys with one peak of heat absorption in a DSC curve between its solidus and liquidus temperatures.
  • FIG. 3 represents a “twin-peak” alloy with two peaks of heat absorption in a DSC curve between its solidus and liquidus temperatures with the first peak being greater in magnitude than the second peak. The major portion of the melting occurs at the first peak.
  • FIG. 4 represents a “multiple-peak” alloy with three peaks of heat absorption in a DSC curve between its solidus and liquidus temperatures, with the first two peaks being about equal in magnitude, and the major portion of the melting occurring at these first two peaks.
  • FIG. 3 represents a “twin-peak” alloy with two peaks of heat absorption in a DSC curve between its solidus and liquidus temperatures with the first peak being greater in magnitude than the second peak. The major portion of the melting occurs at the first peak.
  • FIG. 4 represents a “multiple-peak” alloy with three peaks of heat absorption in a DSC curve between its solidus
  • FIG. 5 represents a multiple peak alloy with three peaks of heat absorption in a DSC curve between its solidus and liquidus temperatures, with the first two peaks being greater in magnitude than the second and third peaks, occurring at the start of melting; and the major portion of the melting occurring at the first two peaks.
  • FIG. 6 represents a multiple peak alloy with four peaks of heat absorption in a DSC curve between its solidus and liquidus temperatures, with the first two peaks being about equal in magnitude with the third and the fourth peaks. About half of the melting occurs at the first two peaks and the other half occurs at the third and fourth peaks. As evidenced by these DSC curves, the alloy compositions of FIGS. 3-6 display a gradual and slow melting pattern that is characteristic of the anti-tombstoning effect.
  • the melting behavior associated with a high mass fraction at onset of melting generally appears more prevalent in an alloy with multiple endothermic peaks in a DSC scan, the principle also applies to single endothermic peak as well.
  • the mass fraction can be obtained using a symmetry method, with the mirror plane passing through the peak of the first large endothermic peak.
  • the symmetrical peak represents an idealized melting behavior of an eutectic alloy, where the residual area can be considered a solidus state.
  • FIG. 7 illustrates a DSC curve for a Sn—Ag—Cu alloy composition as represented in FIG. 4 with a symmetrical peak fit to the first endothermic peak. From this symmetrical fit, the mass fraction of the Sn96.5Ag3Cu0.5 alloy composition was estimated to be 64% as shown in FIG. 7 . It should be noted that a material with single melting point, such as pure indium metal, exhibits a symmetrical endothermic peak.
  • a symmetrical virtual endotherm peak could be constructed on the low temperature end, with the first peak on the left of the DSC endotherm being the peak of the symmetrical endotherm.
  • DSC width represents a difference between the onset and the end temperature of the melting peak of the heating endotherms of Sn—Ag—Cu alloys, using a Sn63Pb37 alloy for comparison.
  • the width of a DSC peak often reflects the mass fraction of solid at the onset of melting.
  • the results of heat absorption, the DSC width ( ⁇ T), and the normalized tombstoning frequency for the various Sn—Ag—Cu alloy compositions of the present disclosure are provided in Table 2.
  • the width of the DSC peak ( ⁇ T) was found to correlate directly with the tombstoning frequency.
  • the mass fraction of solder alloys at the onset of solder melting gradually increases with decreasing Ag concentration in Sn—Ag—Cu alloys.
  • multiple endothermic peaks gradually appeared as the concentration of Ag decreased in the Sn—Ag—Cu alloys.
  • the present disclosure is directed to compositions of Sn—Ag—Cu with substantially reduced tombstoning frequency.
  • a single narrow endothermic peak corresponds to a rapid melting of the solder.
  • the solder paste at one end of the component melts while the other end does not.
  • the wetting force of the molten solder is greater than the adhesion between an un-melted solder paste to the component, and therefore causes tombstoning.
  • a broad single peak, or a twin, or multiple endothermic peaks in the DSC curve indicates the presence of solid phase at onset of melting. This presence of solid phase results in a sluggish wetting leading to a more balanced wetting force at both ends of the component, and consequently to a lower tombstoning frequency.
  • FIG. 8 illustrates the bar chart of the tombstoning frequency of the various Sn—Ag—Cu alloy compositions of the present disclosure.
  • the tombstoning results of the Sn—Ag—Cu alloys were normalized with respect to Sn95.5Ag3.8Cu0.7, which was one of the most widely used lead-free solder compositions, and was used as a standard in the test.
  • Sn97.6Ag2Cu0.5 alloy composition exhibited improved tombstoning result, which is in contrast with the claim made by Katoh (U.S. Pat. No. 6,554,180 B1).
  • the Sn97.5Ag2Cu0.5 alloy composition would be expected to show a tombstoning effect because he states that in order to minimize the tombstoning defect, the first peak of the twin peak alloy should not be much larger than the second peak of the “twin-peak” alloy.
  • this anti-tombstoning behavior of Sn97.6Ag2Cu0.5 alloy in this disclosure can only be explained by the mechanism of mass fraction of solid at onset of melting of solder.
  • the main embodiment of the present disclosure comprises various Sn—Ag—Cu alloy compositions
  • these alloys may also be modified to improve the physical and mechanical properties, including the oxidation resistance.
  • the elements that improve strength consist of Sb, Cu, Ni, Co, Fe, Mn, Cr and Mo.
  • the Sn—Ag—Cu alloys could be modified to improve the mechanical properties without sacrificing the anti-tombstoning effect with one or combinations of the following elements: Sb, Cu, Ni, Co, Fe, Mn, Cr, and Mo.
  • the preferred concentration of the doping agent overall is not to exceed 1 weight % of the solder alloy.
  • the melting temperature of the Sn—Ag—Cu could be lowered by adding elements such as Bi, In, and Zn.
  • the preferred concentrations of the overall additions of either one or a combination of these elements are no greater than 3 weight % of the solder alloy.
  • the Sn—Ag—Cu alloys may also modified by adding oxidation resistant elements such as P, Ga, and Ge. Because the melting temperature of the Sn—Ag—Cu alloys could be undesirably increased if the concentration of the aforementioned elements are too high, the overall maximum concentration of one or a combination of P, Ga, and Ge should be 0.5 weight % of the solder alloy.
  • soldering is an operation in which metallic parts are joined by a molten solder alloy whose melting temperature is generally below 450° C.
  • solder alloys based on tin and lead, but most recently, due to concerns about environmental and safety issues, Sn—Ag—Cu alloys have been widely used in soldering for electronics assembly.
  • the technique of making solder paste is to mix solder powder with flux. First, the solder alloys are produced by melting ingredient metal ingots and mixing them into solder alloys. Then, the alloys are further atomized to solder powder by either a gas atomization or centrifugal atomization.
  • soldering using a solder paste is called reflow soldering, which is considered the most widely employed soldering method in current electronic industries.
  • solder paste which is used to remove the metal oxide, thus allowing the solder to react with the pieces being joined; the solder paste is generally composed of metal powder plus flux or a reducing agent
  • the solder paste is printed onto pads on a print circuit board.
  • a component is placed on the solder paste deposits.
  • the solder paste is heated above the melting temperature of the constituent solder alloy, and thus produces molten solder between the component and the pads.
  • solder joints are formed.
  • a tombstoning test may be performed using an exaggerated severe soldering condition to produce tombstoning.
  • the conditions are shown as follows:
  • a vapor phase reflow oven is employed.
  • the oven is full of vapor generated by heating a high boiling point fluid such as freon with coils at the bottom of the oven.
  • a high boiling point fluid such as freon with coils at the bottom of the oven.
  • the solder paste is heated by the hot vapor and results in soldering of the components.
  • the tombstoned components are counted and the percentage of tombstones with respect to the number of components is used for comparison.
  • a 20 cm ⁇ 15.2 cm board with Cu pads is employed for testing the tombstoning effect.
  • Four identical patterns with various pad sizes and spacings are on the tombstoning board, and these patterns are divided into two pairs of patterns in mirror image with each other to reduce the possible reflow differences.
  • 169 of 0402 chips were placed on each pair of patterns, of which one pair of patterns was used as the control paste and the other as the target paste.
  • the pastes were printed alternately on these two pair of patterns.
  • the tombstoning results were generated using Sn97.5Ag2Cu0.5, Sn96.7Ag2.5Cu0.8, Sn96.5Ag3Cu0.5, Sn96Ag3Cu1, and Sn95.5Ag3.8Cu0.7 pastes, which consist of the respective alloy powders with a rosin-based mildly activated flux (e.g., 60% rosin, 5% dimethylamine hydrochloride, 15% glycerol, 20% rheological and other minor components).
  • the tombstoning frequency is illustrated in Table 3. TABLE 3 Sn95.5Ag3.8Cu0.7 Sn96.5Ag3.5Cu1 Sn95.5Ag3Cu0.5 Sn96.7Ag2.5Cu0.8 Sn97.5Ag2Cu0.5 2.14% 6.4% 1.04% 0.22% 0.22%
  • Sn—Ag—Cu alloys herein may be applicable to alloys consisting of Sn—Ag and Sn—Cu alloys, which may be modified with dopants to improve their physical and mechanical properties, including oxidation resistance.
  • the elements for improving mechanical properties may consist of one or combinations of the following elements: Sb, Cu, Ni, Co, Fe, Mn, Cr, and Mo.
  • elements used for improving the oxidation resistance may, for example, consist of P, Ga, and Ge.
  • elements used for lowering the melting temperature of the alloys may, for example, consist of Bi, In, and Zn.

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US10/935,118 2003-11-06 2004-09-08 Anti-tombstoning lead free alloys for surface mount reflow soldering Abandoned US20050100474A1 (en)

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US10/935,118 US20050100474A1 (en) 2003-11-06 2004-09-08 Anti-tombstoning lead free alloys for surface mount reflow soldering
CN2004800318841A CN101072886B (zh) 2003-11-06 2004-11-02 用于表面贴装回流钎焊的抗竖碑无铅合金
EP04810184A EP1685586A4 (fr) 2003-11-06 2004-11-02 Alliages exempts de plomb anti-delaminage pour soudage par refusion d'un montage en surface
PCT/US2004/036256 WO2005048303A2 (fr) 2003-11-06 2004-11-02 Alliages exempts de plomb anti-delaminage pour soudage par refusion d'un montage en surface
US12/576,123 US20100116376A1 (en) 2003-11-06 2009-10-08 Anti-tombstoning lead free alloys for surface mount reflow soldering

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US20070048172A1 (en) * 2005-08-30 2007-03-01 Indium Corporation Of America Technique for increasing the compliance of tin-indium solders
US20070071634A1 (en) * 2005-09-26 2007-03-29 Indium Corporation Of America Low melting temperature compliant solders
WO2007070548A3 (fr) * 2005-12-13 2007-11-22 Indium Corp America Alliages de brasage sans plomb et joints de brasage de ceux-ci d'une resistance amelioree aux impacts de chute
EP1785498A3 (fr) * 2005-11-15 2007-11-28 Hitachi Metals, Ltd. Alliage de brasage, bille de brasage et joint de brasage utilisant cet alliage
WO2008073090A1 (fr) * 2006-12-13 2008-06-19 Halliburton Enegery Servies, Inc. Alliage de brasage exempt de plomb pour ensembles de cartes de circuits imprimés pour des environnements à haute température
US20110147066A1 (en) * 2009-12-17 2011-06-23 Sidhu Rajen S Substrate metallization and ball attach metallurgy with a novel dopant element
US20110163441A1 (en) * 2008-09-16 2011-07-07 Agere Systems Inc. Pb-free solder bumps with improved mechanical properties
EP2468450A1 (fr) * 2010-10-29 2012-06-27 Harima Chemicals, Inc. Alliage de soudure à faible teneur en argent et composition de pâte à souder
US20130343809A1 (en) * 2012-04-09 2013-12-26 Senju Metal Industry Co., Ltd. Solder alloy
US20140290931A1 (en) * 2013-04-01 2014-10-02 University Of Maryland, College Park High Temperature Solder For Downhole Components
US8968488B2 (en) * 2006-07-05 2015-03-03 Fuji Electric Co., Ltd. Cream solder and method of soldering electronic part
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EP1685586A4 (fr) 2007-12-26
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WO2005048303A2 (fr) 2005-05-26
CN101072886B (zh) 2013-11-13
CN101072886A (zh) 2007-11-14
WO2005048303A3 (fr) 2007-04-26

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