2013 Roadmap | iNEMI

2013 Roadmap | iNEMI:

The 2013 Roadmap was developed by 20 Technology Working Groups (TWGs) in response to inputs regarding technology needs from representatives of OEMs in six Product Emulator Groups (PEGs). These groups included more than 650 individuals from over 350 corporations, consortia, government agencies and universities, located in 18 countries.

Download highlights of the Executive Summary (PDF).

View sample pages (PDF)

Press release (May 14, 2013)

WEBINARS: Introduction to the 2013 Roadmap plus highlights of selected chapters (requires log-in; if you do not have a web account, create one now).

2013 Product Emulator Groups (PEGs)
1.    Aerospace/Defense
2.    Automotive
3.    Consumer/Portable
4.    High-End Systems
5.    Medical
6.    Office Systems

The PEGs define OEM requirements for their respective product sectors, anticipating product technology and business-related needs over a 10-year horizon. These needs are presented in each PEG chapter, using key attribute spreadsheets and text according to templates that are furnished by the iNEMI Technical Committee (TC).  Each PEG has a Chair or Co-chairs and as many group members as needed for a broad-based view of that emulator’s scope (usually 2-5 individuals).

The TWGs use the OEM requirements detailed in the six PEG chapters (as applicable) to prepare each of their roadmap chapters, detailing where their respective technology stands today — and is expected to progress over the next 10 years — with respect to the stated needs.

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FCT Assembly to Present New Technology for Paste Printing at the SMTA Toronto Expo

EMSNow: FCT Assembly will exhibit at the upcoming SMTA Toronto Expo and Tech Forum, scheduled to take place Thursday May 16, 2013 at the Sheraton Toronto Airport Hotel & Conference Centre in Ontario. Keith Howell, Technical Director at Nihon Superior, will hold a technical presentation on nano silver replacement for high lead solders in semiconductor junctions. Keith works closely with the FCT Assembly team, a licensee for Nihon Superior'sSN100C.

FCT Assembly has developed the world's most advanced stencil technology for solder paste printing.  The technology is comprised of a specifically engineered nano coating applied over its proven Slic™ stencil. The technology is surprisingly cost-effective, making improved yields available to all levels of the industry. The technology can be used with current assembly equipment and processes.

The new NanoSlic™ stencil is based on the proven Slic™ stencil with its advanced foil composition and FCTA's state-of-the-art laser cutting process. Then, a permanent nano coating is applied that is based on a revolutionary chemistry platform called Hybrid-T Technology™. The coating imparts a highly hydrophobic and oleophobic surface to the bottom of the stencil and aperture walls. The robust coating should last the life of the stencil.

Using the newly developed NanoSlic™ coating system, NanoSlic™ is sprayed onto the stencil surface and aperture walls, reducing bridging and significantly improving paste release, permitting consistent printing of the smallest area ratios. The technology will be applied by FCT Assembly in its various locations. The user will see following benefits immediately: reduced bridging, reduced underside cleaning, improved paste release and improved yields.

An added benefit, the NanoSlic™ coating, is environmentally friendly. It does not use any Perfluorooctanoic acid (PFOA), a toxic substance currently being investigated by the EPA.

www.fctassembly.com.

Method for inhibiting growth of intermetallic compounds

Espacenet - Bibliographic data: The present invention relates to a method for inhibiting growth of intermetallic compounds, comprising the steps of: (i) preparing a substrate element including a substrate on which at least one layer of metal pad is deposited, wherein at least one layer of solder having a thin thickness is deposited onto the layer of metal pad, and then carry out reflowing process; and (ii) further depositing a layer of solder with an appropriate thickness on the substrate element, characterized in that a thin intermetallic compound is formed by the reaction of the solder having a thin thickness and the metal in the metallic pad after appropriate heat treatment of the thin solder. In the present invention, the formation of thin intermetallic compound is able to slow down the growth of the intermetallic compound and to prevent the transformation of the intermetallic compounds. Once the growth of the intermetallic compounds can be inhibited, the growth of Sn whiskers can also be inhibited.

     TW201308451  (A)  -  Method for inhibiting growth of intermetallic compounds
Inventor(s):     CHEN CHIH [TW]; TU KING-NING [US]; HSIAO HSIANG-YAO [TW] +
Applicant(s):     UNIV NAT CHIAO TUNG [TW] +

100°C drop in melting point could help make Nano-Solders a reality

Reduction synthesis of tin nanoparticles using various precursors and melting behavior - Springer: "To achieve a more significant melting point drop through finer particles, chemical reduction synthesis of tin nanoparticles were conducted using four tin precursor agents: tin(II) acetate, tin(II) chloride, tin(II) sulfate, and tin(II) 2-ethylhexanoate. Depending on the precursor type, the sizes and size distributions of the synthesized Sn nanoparticles were highly diverse. Tin nanoparticles synthesized with tin(II) sulfate or tin(II) 2-ethylhexanoate displayed characteristics of monodispersity at reduced size. The nanoparticles had average diameters of just ∼3 nm and ∼6 nm, respectively, and exhibited melting points of 102.2°C and 131.1°C, which represented extreme drops by 130.4°C and 101.5°C in comparison with the melting point of bulk tin."

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Electronics Manufacturing by Inkjet Printing

Inkjet printing is of great interest in the field of electronics manufacture because its digital nature negates the need for physical tooling. A wide variety of active and passive materials are currently being investigated for use in inkjet printed electronics. These include semiconductors, light emitters and photovoltaic materials as well as dielectric materials and straight forward conductors. The range of conducting materials that can be printed is somewhat limited by the constraints of inkjet printing. Ideally, particle sizes should be below 1 micron and the viscosities and surface tensions of the fluids need to be tailored to the particular printhead being used. Regardless of these limitations, various technologies are now being implemented in the production of circuit boards, interconnects and antennas by inkjet printing. The properties of these inkjet
printed circuits do not currently mimic traditional PCB materials – in particular, the sheet resistances of inkjet printed materials tend to be significantly higher than traditional copper clad laminate and the minimum feature sizes are somewhat larger than state of the art semi-additive plating. However, inkjet printed circuit technologies are a still finding many applications which are particularly well suited to their properties and the digital nature of their application.



Steve Thomas
 Conductive Inkjet Technology Ltd.
 Cambridge, England


http://www.ipcoutlook.org/pdf/inkjet_printing_ipc.pdf

Solder foams, nano-porous solders, foamed-solder balls

A foamed solder or a nano-porous solder is formed on a substrate of an integrated circuit package. The foamed solder exhibits a low modulus that resists cracking during shock and dynamic loading. The foamed solder is used as a solder bump for communication between an integrated circuit device and external structures.



Page bookmark TWI358340  (B)  -  Solder foams, nano-porous solders, foamed-solder b
Inventor(s): CHOE HEEMAN [KR]; SUH DAEWOONG [KR] +
Applicant(s): INTEL CORP [US] +
Classification:
- international: B23K35/02; B23K35/14; H01L21/66
- European: B23K35/02D5P; B23K35/22; H05K3/34C4B; H05K3/34F1
Application number: TW20060146439 20061212 
Priority number(s): US20050323218 20051230
Also published as:
US2007152016  (A1)   US7745013  (B2)   WO2007078717  (A2)   WO2007078717  (A3)   KR20080083127  (A)   more 

Solder powders manufacture process by the wire explosion method

Scopus: Now that solder powders, which are key components of all the solder pastes, have been finer to meet the needs of the electronic industry, the wire explosion method to make solder powders smaller is being one of the ways to be in the spotlight. The wire explosion method is the powder making process using the wire form of solder. As the solder feeder moves the solder wire to the chamber full of argon gases, the wire evaporates in the electrical explosion. Then, it is solidified into the powder. The K factor, the wire feeder length, the speed, the voltage, the wire diameter are main variables in the process of making solder powders in this study. As a result of the study, 45% of the solder powders are in the range of type 6(5∼15um). Those are effectively accepted to be used after taking the tensile test, the hot zone test, the thermal shock test.


IBSC 2012 - Proceedings of the 5th International Brazing and Soldering Conference
2012, Pages 27-31
5th International Brazing and Soldering Conference, IBSC 2012;Las Vegas, NV;22 April 2012through25 April 2012;Code90195
Solder powders manufacture process by the wire explosion method  ( Conference Paper )

Kim, S. , Kim, S.H.  

RIST, Research Institute of Industrial Science and Technology, 32 Hyoja-Dong, Pohang City, 790-330, South Korea

SOLDER POWDER AND PROCESS FOR PRODUCING SOLDER POWDER

Espacenet: To obtain a solder powder having an average particle diameter of 0.05 [mu]m or more but less than 3 [mu]m. [Solution] A solder powder having an average particle diameter of, for example, 0.05 [mu]m or more but less than 3 [mu]m is obtained by using a process for solder powder production which comprises a step in which a solid or liquid metal, a nonaqueous solvent, and balls for pulverization which have a diameter of 0.05-5 mm are introduced into a vessel to obtain a mixture, a step in which the mixture is heated to 150 C or higher and stirred, a step in which the balls for pulverization are separated from the stirred mixture to obtain a mixture of a solder powder and the nonaqueous solvent, and a step in which the solder powder/nonaqueous-solvent mixture is subjected to solid/liquid separation to obtain the solder powder.

Page bookmark     WO2012066664  (A1)  -  SOLDER POWDER AND PROCESS FOR PRODUCING SOLDER POWDER
Inventor(s):     ISHIKAWA YUICHI [JP] +
Applicant(s):     DOWA HOLDINGS CO LTD [JP]; ISHIKAWA YUICHI [JP] +
Classification:    
- international:     B22F9/06
- european:    
Application number:     WO2010JP70562 20101118
Priority number(s):     WO2010JP70562 20101118 

Effects of magnetic fields on microstructure, microhardness and electrochemical corrosion of Sn-9Zn solder

Scopus: The microstructure and property of Sn-9Zn solder were investigated under static magnetic field and rotary magnetic field of 0.125 T by XRD, SEM and electrochemical detector system. The results show that both static magnetic field and rotary magnetic field can refine the microstructure of Sn-9Zn solder, and Zn phase is rotating as well, the microhardness of Sn-9Zn solder under static magnetic field and rotary magnetic field increase by 7.4% and 10.2%, reaching to 18.8 HV and 19.3 HV, respectively, compared with the solder without magnetic field.

While the corrosion potential of the solder under static magnetic field and rotary magnetic field decrease slightly and the corrosion current density obviously declines, which improves the solder corrosion property.

Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals
Volume 22, Issue 2, February 2012, Pages 485-489
Effects of magnetic fields on microstructure, microhardness and electrochemical corrosion of Sn-9Zn solder

Wu, M.ab , Liu, Z.-J.a 

a  School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110023, China
b  School of Mechanical Engineering, Liaoning Shihua University, Fushun 113001, China
 

Spherical solder reflow method for making solder balls

US8162203: Various technologies exist for depositing solder bumps on to IC devices at the wafer level, including, for example, evaporation, electroplating, screen-printing, jetting, ball dropping, and Controlled Collapse Chip Connect New Process (i.e., C4NP) These deposition methods are often referred to as solder wafer bumping or C4 wafer bumping. Originally, solder wafer bumping was accomplished by evaporating both the ball-limiting metallurgy (BLM) and solder through mask holes in an array fashion onto the wafer surface. As the demand for higher I/O density, and lower cost of flip-chip interconnections has increased, however, other deposition methods have been developed. For example, ball drop methods, used to make micro-size solder balls, have recently gained attention in the industry because these methods allow for flexibility in the solder alloys used and finer pitch applications. Indeed, in U.S. Pat. No. 6,517,602, Sato et al. disclose a method of forming solder balls by using a droplet spraying method. This method enables production of micro-sized solder balls, but does not enable formation of solder balls having diameters less than 50 microns due to nozzle-size limitations. Furthermore, the process described by Sato et al. does not produce uniform solder balls, and thus a secondary sorting process is needed to obtain solder balls of the same size.
    More recently, injection molded solder (IMS) processing has been used as a cost-effective solder wafer bumping method. While solder balls formed by IMS are usually more uniform in size than those produced by “ball drop” techniques, the uniformity of the solder balls can be lost if the solder balls escape from the mold plate and are allowed to merge with one another after reflowing occurs. Therefore, it would be desirable to develop an IMS process wherein merging or bridging of the solder balls is reduced or prevented.
SUMMARY OF THE DISCLOSURE
    The present disclosure provides IMS methods that reduce and/or prevent bridging of two or more solder balls during reflow of the solder. The IMS methods of the instant disclosure provide cost-effective processes of making two or more solder balls that are uniform in size.
    A first aspect of the present disclosure is a method of preventing or reducing bridging of two or more solder balls during an injection molded soldering process comprising:


US United States of America

   
Inventor:     Gruber, Peter A.; Mohegan Lake, NY, United States of America
Nah, Jae-Woong; New York, NY, United States of America

Assignee:     International Business Machines Corporation, Armonk, NY, United States of America
other patents from INTERNATIONAL BUSINESS MACHINES CORPORATION (280070) (approx. 44,393)
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Published / Filed:     2012-04-24 / 2011-02-18

Application Number:     US2011000030594

IPC Code:     Advanced: B23K 31/02;

U.S. Class:     228/256; 228/180.22; 228/246; 228/260;

Field of Search:     Non/00e

Priority Number:    
2011-02-18      US2011000030594

KICs 247 Wave Revolutionizes the Wave Process in Asia - 2012 EM Asia Innovation Award

Thomasneta: KIC announces that it has been awarded a 2012 EM Asia Innovation Award in the category of Software - Process Control Tools for its KIC 24/7 Wave. The award was presented to Ronnie Teo during an April 26, 2012 ceremony in Shanghai during NEPCON China.

The new KIC 24/7 Wave utilizes embedded sensors in the wave solder machine to automatically measure the thermal profile for each and every processed PCB to the acceptable process window. A thermocouple also is installed in the solder pot to constantly measure the pot temperature. In addition, the KIC 24/7 Wave reduces setup time by quickly suggesting the most optimum recipe for each and every PCB.

Any out of spec situation is immediately identified, while the standard SPC charts automatically provide Cpk numbers with the ability to provide alarms when the process starts drifting. Every PCB profile is recorded for easy retrieval for full process traceability. Traceability down to the individual PCB is achieved when bar codes are used.

The initial programming of the KIC 24/7 Wave is performed with a KIC profiler. The KIC profiler is capable of quickly identifying the appropriate wave solder settings for an improved process.

Established in 2006, the EM Asia Innovation Awards program strives to recognize and celebrate excellence in the Asian electronics industry, inspiring companies to achieve the highest standards and push the industry forward.

Electromigration in copper-core solder ball joints during thermal cycle tests

Scopus: Electromigration current densities in Cu and Al lines on a silicon die exceed 1.0�10 6 A/cm 2. However, solder joints can only withstand electromigration current densities below about 1.0�10 4 A/cm 2. Thus, electromigration in solder joints will become a problem in semiconductor packages in the near future. Previous studies demonstrated that Cu-core solder balls increased the electromigration lifetime and led to better current stability at temperatures below 423K. This is because electrons flow through the Cu cores, reducing the current density on the cathode side, which is where electromigration occurs. In the present study, we forcused on the reliability of solder joints in a combined environment by examining the effect of thermal cycle tests on the current in a new test sample. A new test sample for the evaluation of joining reliability by using Cu-core solder balls in a combined enbironment was made.

In initial tests, this test sample exhibited similar results to those observed in previous studies. Cu-core solder balls subjected to cyclic testing at 233/398K and a current density of 1.0×10 4 A/cm2 exhibited lower reliabilities than when there was no current.

Examination of cross-sections of the solder balls after reliability testing revealed that the combined environment accelerated growth of intermetallic compounds and cracks in the joining region. In a combined environment, Cu-core balls were converted into intermetallic compounds on the anode side. This phenomenon is thought to occur due to the different electrical resistivities of Cu-Sn intermetallic compounds.

ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems, InterPACK 2011
Volume 2, 2011, Pages 719-723
ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems, InterPACK 2011;Portland, OR;6 July 2011through8 July 2011;Code89456
Electromigration in copper-core solder ball joints during thermal cycle tests  ( Conference Paper )

Fujiwara, S.a, Chiwata, N.b, Fujiyoshi, M.c, Wakano, M.d, Tanie, H.e 

a  Hitachi, Ltd., Yokohama, Kanagawa, Japan
b  Hitachi Metals, Ltd., Minato-ku, Tokyo, Japan
c  Hitachi Metals, Ltd., Yasugi, Shimane, Japan
d  NEOMAX Kagoshima Co., Ltd., Izumi, Kagoshima, Japan
e  Hitachi, Ltd., Hitachinaka, Ibaraki, Japan

Development of highly reliable BGA and flip-chip structures by using Cu-cored solder ball

Scopus: A Cu-cored solder joint is a micro-joint structure in which a Cu sphere is encased in solder. It results in a more accurate height and has low thermal and electrical resistance. In a previous paper, we examined the thermal fatigue life of a Cu-cored solder ball grid array (BGA) joint through actual measurements and crack propagation analysis. As a result, we found that the thermal fatigue life of a Cu-cored solder BGA joint is about twice as long as that of a conventional joint

In this paper, we describe the impact strength of a Cu-cored solder BGA joint determined by conducting an impact bending test. This test is a technique to measure the impact strength of a micro-solder joint. This method was developed by Yaguchi et al., and they confirmed that it is an easier and more accurate method of measuring impact strength than the board level drop test. First, we simulated the impact bending test by finite element analysis (FEA) and calculated solder strains of both Cu-cored solder joints and conventional joints. The results indicated that the maximum solder strain of a Cu-cored solder joint during the impact bending test was slightly smaller than that of a conventional joint. The solder volume of the Cu-cored solder joint was also smaller than that of a conventional joint. On the other hand, joint stiffness of the Cu-cored solder joint was larger than in a conventional joint. The former increases the solder strain of the Cu-cored solder joint, and the latter decreases it. By balancing these phenomena, it is possible to obtain a maximum solder strain in the Cu-cored solder joint that is slightly smaller than in a conventional joint. Based on these phenomena, the impact strength of the Cu-cored solder joint is predicted to be the same as or higher than that of a conventional joint. Therefore, we measured the impact strengths of a Cu-cored solder joint and a conventional joint using the impact bending test.

As a result, we confirmed that the impact strength of the Cu-cored solder joint was the same as or higher than that of a conventional joint. Accordingly, a Cu-cored solder BGA joint is a micro-joint structure that makes it possible to improve thermal fatigue life without decreasing impact strength. Moreover, we investigated whether the use of Cu-cored solder in a flip-chip (FC) joint improved its reliability. As a result, we found that the stress of an insulating layer on a Si die surface was reduced by using a Cu-cored solder FC joint. This is because bending deformation of the Cu land occurs, and the difference in thermal deformation between the Si chip and the Cu land becomes small. Accordingly, the Cu-cored solder FC joint is a suitable structure for improving reliability of a low-strength insulating layer.

ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems, InterPACK 2011
Volume 2, 2011, Pages 725-732
ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems, InterPACK 2011;Portland, OR;6 July 2011through8 July 2011;Code89456
Development of highly reliable BGA and flip-chip structures by using Cu-cored solder ball  ( Conference Paper )

Tanie, H.a , Chiwata, N.b, Wakano, M.c, Fujiyoshi, M.d, Fujiwara, S.e 

a  Hitachi, Ltd., 832-2, Horiguchi, Hitachinaka, Ibaraki, 312-0034, Japan
b  Hitachi Metals, Ltd., Tokyo, Japan
c  Neomax Kagoshima Co., Ltd., Kagoshima, Japan
d  Hitachi Metals, Ltd., Shimane, Japan
e  Hitachi, Ltd., Kanagawa, Japan

METHOD FOR FORMING TIN OR SOLDER COAT FILM AND DEVICE THEREFOR (WO2012060022A1)

WO2012060022A1A method for forming a tin or solder coat film on a small electrode pad or on a lead surface with a narrow pitch on an electronic circuit substrate or in an electronic component, the method including: a first step of placing tin or solder particles on a cleaned pad or a cleaned lead surface that is exposed on the electronic circuit substrate or an electronic component assembly (hereinafter referred to as "workpiece"), wherein the surface except the pad or the lead is covered by a solder resist film; a second step of fusing, as cores, the tin or solder particles on the pad or the lead surface to form the tin or solder coat film; and a third step of spraying high-temperature organic fatty acid solution on a surface of the tin or solder coat film to blow away the excessively attached tin or solder. Consequently, a uniform tin or solder coat film having the thickness of 2 to 20 um with the thickness variation being  3 um or less is formed on the pad or the lead

ISHIKAWA HISAO; Japan 〒32
YOKOYAMA MASANORI; Japan 〒32
Assignee:     HORIZON TECHNOLOGY LABORATORY CO., LTD. Japan〒32
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Published / Filed:     2012-05-10 / 2010-12-16
Application Number:     WO2010JP0073262

Reducing Formation Of Oxide On Solder (US20120111925A1)

US20120111925A1: In certain embodiments, a system includes a deposition system and a plasma/bonding system. The deposition system deposits a solder outwardly from a substrate of a number of substrates. The plasma/bonding system comprises a plasma system configured to plasma clean the substrate and a bonding system configured to bond the substrates. The plasma/bonding system at least reduces reoxidation of the solder.
In certain embodiments, a method comprises depositing solder outwardly from a substrate, removing metal oxide from the substrate, and depositing a capping layer outwardly from the substrate to at least reduce reoxidation of the solder.

Certain embodiments of the invention may provide one or more technical advantages. A technical advantage of one embodiment may be that a plasma/bonding system may be used to at least reduce (or even prevent) formation of metal oxide. The system may plasma clean and then bond wafers without exposing the wafers to oxygen, which may at least reduce formation of metal oxide. A technical advantage of one embodiment may be that a capping layer may protect a wafer from exposure to oxygen, which may reduce formation of metal oxide.

Inventor:     Diep, Buu; Murphy, TX, United States of America
Kocian, Thomas A.; Dallas, TX, United States of America
Gooch, Roland W.; Dallas, TX, United States of America

Assignee:     Raytheon Company, Waltham, MA, United States of America
other patents from RAYTHEON COMPANY (466005) (approx. 2,859)
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Published / Filed:     2012-05-10 / 2011-09-13

Lead-free solder foil for use in component packaging - stacked semiconductor wafers

US20120111924A1: According to an aspect of the invention, there is provided a lead-free solder including an alloy rolled into a shape of sheet. The alloy includes: tin; from 10 wt % to less than 25 wt % of silver; and from 3 wt % to 5 wt % of copper. And the alloy is free from lead.
The alloy may include 10 wt % to 20 wt % of silver. The alloy may have a shape of sheet with a thickness from 40 μm to 120 μm. The alloy may have a shape of a disk with the same diameter as a joined member, for example, a semiconductor wafer.
According to another aspect of the invention, the solder or materials thereof are not powdered, and thin sheet-shaped lead-free solder which is an alloy containing tin, silver, and copper as main components can be obtained.
The lead-free solder according to the present invention has an advantage in that, the solder and materials thereof are alloyed and rolled in a shape of a thin sheet without powdering the solder and materials thereof, so that costs are reduced.

MAKITA, Kazuyuki; Tokyo, Japan
ICHINOSE, Masaki; Tokyo, Japan
WATASHIMA, Taketo; Tokyo, Japan
SOUTOME, Masayuki; Tokyo, Japan
YAMASHITA, Mitsuo; Tokyo, Japan
ASAGI, Takeshi; Tokyo, Japan
HIRAI, Masatoshi; Tokyo, Japan
MURATA, Toru; Tokyo, Japan

Assignee:     FUJI ELECTRIC SYSTEMS CO., LTD., Tokyo, Japan
other patents from FUJI ELECTRIC SYSTEMS CO., LTD. (844106) (approx. 1)
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Published / Filed:     2012-05-10 / 2012-01-18

A study of microstructural development, hardness and micro-creep of Sn-3.5Ag-0.7Cu lead-free solder alloy prepared by rapid solidification

Scopus: The Sn-3.5Ag-0.7Cu lead-free solder alloy has been prepared by normal casting and melt-spinning techniques to investigate the microstructural development, hardness and micro-creep of this alloy due to rapid solidification.

The microstructure of the rapidly solidified ribbons and ingot samples has been investigated by SEM and X-ray diffraction (XRD) techniques. The results showed that the structure of the alloy prepared by normal casting is composed of Cu-Sn and Ag-Sn IMCs finely dispersed in Sn matrix, while these fine dispersions are not present in the rapidly solidified sample indicating that the rapid solidification rate is high enough to retain most of the Ag and Cu elements in nonequilibrium supersaturated solid solutions of β-Sn. Additionally, the mechanical properties of both slowly and rapidly cooled samples are examined by using Vickers microhardness tester at different loads in the range of them 0.098 to 4.9 N. The hardness value of the rapidly cooled sample was found to be 1.3 times higher than that of the slowly cooled sample due to refinement of the rapidly cooled sample as well as the nonequilibrium solid solutions of Ag and Cu in the β-Sn matrix. Besides, indentation creep behavior of both slowly and rapidly cooled samples is examined by using Vickers microhardness tester for three different values of the applied loads.

Polymer-Core solder balls anyone?

Polymer-Core solder balls anyone? | LinkedIn: Dag Andersson • Just started a Eurostars project on PCSB. Will inform the group when first results are published.

Could be a news item - if Dag is prepared to talk about it.

Dag.Andersson@swerea.se
00 46 31 706 6141
00 46 707 80 6141

UK research projects in microelectronics

Iemrc network:

Projects on tin whiskers, lead-free joint modelling, nanocomposites...

Variable melting point solders

Espacenet: The present invention relates to variable melting point solder formulations. The solder is comprised of at least one base metal or base metal alloy, preferably alloyed with at least one melting point depressant metal, such that the solidus point of the solder composition is reduced to an initial solidus temperature. Said base metal or base metal alloy, alloyed with at least one melting point depressant metal is mixed with at least one additive metal or additive metal alloy. When heated to a process temperature above said initial solidus temperature, a reaction occurs between the melting point depressant metal, and the additive metal, such that solidification occurs at the process temperature via the formation of intermetallic phases, effectively increasing the solidus of the base metal, and of the overall solder

    US2012055586  (A1)  -  VARIABLE MELTING POINT SOLDERS
Inventor(s):     MCISAAC DOUGLAS J [CA]; WHITNEY MARK A [CA]; CORBIN STEPHEN F [CA] +
Applicant(s):     DYNAJOIN CORP [CA] +