New nanoalloys for high temperature soldering

New nanoalloys for high temperature soldering:


Nanowerk News) Removing lead from manufacturing processes and products is high priority for the EU. A European research programme has tackled the problem of high-temperature solders used in the electronics industry.
On soldering components on a printed circuit board, it is crucial that the joints do not remelt in subsequent soldering operations. The electronics industry is therefore inclined to use solder material containing a high percentage of lead with a higher melting point (300 °C and above).
One solution is to use so-called nanosolders based on tin-antimony (Sn-Sb) alloys. Nanoparticles have a lower melting point than the bulk substance. Funded by the EU, the project 'A chemical approach to lead-free nanosolders' (Nanosold) aimed to develop new lead-free high-temperature solders with Sn-Sb-M alloys. M is silver (Ag), copper (Cu) and nickel (Ni).
Concentrating on the two ternary alloy systems Sn-Sb-Ag and Sn-Sb-Cu, the Nanosold project investigated the thermodynamic properties, the sum of the features of the individual phases. The team used the so-called 'Computer coupling of phase diagrams and thermochemistry' (Calphad) method enabling the scientists to reliably predict the thermodynamic properties without experimental information.
To refine the phase relations in the Sn-Sb-Ni system, Nanosold used other complementary methods. These included powder X-ray diffraction, electron probe micro-analysis, scanning electron microscopy and differential thermal analysis.
A reduction in melting point of up to 11 °C was achieved using nanoalloys rich in Sn prepared by a chemical reduction method. Particle size was modified to be in the range of 50 to 150 nm which would translate into a size-dependent lowering of soldering temperature in any practical application.
Although there are further problems to be worked on, solder pastes based on nanoalloys would achieve a decrease in melting point. From an environmental point of view, the new nanoalloys remove a very toxic element from electronic appliances' manufacturing.
Source: Cordis



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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 

NanoBond® assembly - A rapid, room temperature soldering process

Scopus: Indium Corporation of America has commercialized a new technology that will revolutionize how manufacturers join components using solder materials. (See Figure 1) The joining process is based on the use of reactive multilayer foils as local heat sources.

The foils are a new class of nano-engineered materials, in which self-propagating exothermic reactions can be ignited at room temperature through an ignition process. By inserting a multilayer foil between two solder layers and two components, heat generated by the reaction in the foil melts the solder and consequently bonds are completed at room temperature in air, argon or vacuum in approximately one second. The resulting metallic joints exhibit thermal conductivities two orders of magnitude higher, and thermal resistivity an order of magnitude lower, than current commercial TIMs (Thermal Interface Material). The use of reactive foils as a local heat source eliminates the need for torches, furnaces, or lasers, speeds the soldering processes, and dramatically reduces the total heat that is needed. Thus, temperature-sensitive or small components can be joined without thermal damage or excessive heating. In addition, mismatches in thermal contraction on cooling can be avoided because components see very small increases in temperature. This is particularly beneficial for joining metals to ceramics. The fabrication and characterization of the reactive foils is described, and the value proposition for NanoBonding is presented. This paper also shows the applicability of this platform technology to many areas of packaging including Thermal Interface Materials, microelectronics, optoelectronics, and Light Emitting Diodes (LEDs)


IBSC 2012 - Proceedings of the 5th International Brazing and Soldering Conference
2012, Pages 32-37
5th International Brazing and Soldering Conference, IBSC 2012;Las Vegas, NV;22 April 2012through25 April 2012;Code90195
NanoBond® assembly - A rapid, room temperature soldering process  ( Conference Paper )

Matteau, J.  

Indium Corporation of America, Utica, NY, United States

NanoBond and NanoFoil from Indium for room temperature soldering

Indium Corporation: NanoBond is RNT’s patented process for bonding components utilizing NanoFoil. Activated by a small pulse of energy, in a fraction of a second, NanoFoil delivers the necessary amount of heat and energy to reflow solder or braze and create a strong, true metallic joint. The process enables high strength, high conductivity bonds between most combinations of materials making it ideal for many joining and assembly operations.

RNT has developed and tailored its patented NanoBond process with each of its customers in mind. The multilayer foil is placed between two components to be bonded, along with two layers of solder, either pre-applied to the components or freestanding. Pressure is applied to prevent the components from moving, and the chemical reaction between the Al and Ni layers in the foil is activated. Heat from the NanoFoil’s reaction melts the solder or brazed layers and enables metallic bonding at room temperature in fractions (thousandths) of a second.

Effect of isothermal aging on Sn-Ag-Cu solder joints on electroless Ni-P/Au plating by laser reflow soldering

Scopus: With the miniaturization of electronic productions and the use of heat sensitive electronic components, the traditional reflow soldering process often has difficulties. As an alternative soldering process, the laser reflow soldering has been recently proposed. To clarify joint properties of the joint soldered by the laser reflow soldering, we investigated the effect of isothermal aging on Sn-Ag-Cu solder joints on electroless Ni- P/Au plating by the laser reflow soldering. Especially, the microstructure at the interface between Sn-Ag-Cu solder and Ni-P/Au plating and joint properties of solder joints were studied


IBSC 2012 - Proceedings of the 5th International Brazing and Soldering Conference
2012, Pages 1-4
5th International Brazing and Soldering Conference, IBSC 2012;Las Vegas, NV;22 April 2012through25 April 2012;Code90195
Effect of isothermal aging on Sn-Ag-Cu solder joints on electroless Ni-P/Au plating by laser reflow soldering  ( Conference Paper )

Nishikawa, H.a , Takemoto, T.a, Iwata, N.b 

a  Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka, Japan
b  Graduate School of Engineering, Osaka University, Suita, Osaka, Japan

Soldering in Space - video

MAKE: The solder, heated, became a molten blob with a droplet of rosin clinging tight to the outside. Solder melts: that’s not too surprising. It’s the behavior of the rosin that amazed. As the temperature increased, the droplet began to spin, round and round, faster and faster, like a miniature carnival ride.

Video

Stencil Design Guidelines have been updated with new materials.

Stencil Design Guidelines have been updated with new materials.: To help designers and board assemblers address challenges of working with new materials and smaller, finer-pitch components, IPC-7525B provides guidelines for design and fabrication of stencils for solder paste and SMT adhesive with discussion on through-hole and mixed technology. This updated standard includes differences for tin-lead and lead-free solder paste, overprint, 2-print, and step stencil designs. Example order form and inspection checklist are also included. 

See all stories on this topic »

Bob Willis new book on "Pin in Hole Intrusive Reflow Book" now available

LinkedIn: Bob Willis new book on "Pin in Hole Intrusive Reflow Book" now available for free download at www.pihrtechnology.com
This what other people say:

Sue Knight, Dennis Price and Peter Starkey give their views ---------

"Once again Bob has managed to write a users guide which gives a good basic overview of the subject, whilst still providing the depth of information to allow those of us who’ve been using PiHR successfully for years to nod sagely in agreement at the nuances and still learn a few new tricks to try in the process. The breakdown of areas prompts a logical progression for designing your first successful PiHR product and associated processes, and provides that most invaluable of resources: pictures, illustrations and notes throughout of what it should look like both when it goes right and when there are problems that need the process engineer’s input.

An excellent book for those embarking on PiHR as a new process and also as a reference manual for more established users."

Sue Knight, Project Engineer
Surface Technology International Ltd.
Chairman of the SMART Group Technical Committee
www.sti-limited.com

New solder jet design for selective soldering from Panasonic

US20120024938A1 A solder drawing member (402) is detachably attached on the outer side of a jet nozzle (303) that jets molten solder pumped from a solder tank (102) storing the molten solder. The solder drawing member (402) is made of a material having higher wettability to the molten solder than the surface material of the jet nozzle (303). Thus a force of separating the solder from a point to be soldered can be increased by a surface tension of the molten solder flowing on the solder drawing member (402), thereby reducing bridge phenomena and icicle phenomena.

In the configuration of Patent Literature 1, unfortunately, excessive solder on the leads 107 cannot be removed. In the configuration of Patent Literature 2, the venturi forming plate 202 is necessary in the nozzle body 203, resulting in a complicated nozzle structure.
An object of the present invention is to provide a soldering apparatus which can reduce bridge phenomena and icicle phenomena

Bosch patent on keeeping wave solder copper content constant

WO2012013437A1The invention relates to a method for stabilizing a concentration (10) of a constituent, in particular a Cu concentration (10), in a solder bath (34). The removal of the constituent from the solder bath (34) by attachment to the component and solder drawn from the solder bath (34) on a discharge side (38) of the solder bath (34) is recorded. Furthermore, the supply of the constituent introduced into the solder bath (34) by detachment from components to be immersed in the solder bath (34) and constituents subsequently introduced in controlled quantities into the solder bath (34) on a feed side (36) is recorded. Depending on the comparison of the amount of the constituent that is supplied on the feed side (36) and the amount of the constituent that is removed on the discharge side (38), the concentration of the constituent within the solder bath (34) is kept constant

ERMER, Martin , Germany WETZL, Franz , Germany Braun, Helmut ; Germany WINKLER, Jens , Germany

ROBERT BOSCH GMBH Germany

News, Profiles, Stocks and More about this company

Published / Filed: 2012-02-02 / 2011-06-29

The KIC 24/7 Wave Advances the Wave Process from Art to Science

EMSNow KIC introduces the new KIC 24/7 Wave, using 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.

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.

For more information about KIC's new Wave 24/7, visit www.kicthermal.com.

ACE Launches Latest Selective Soldering System

SMTONLINE “In addition, we’ll be bringing our new Manual Lead Tinning System, or MLTS,” Cable adds. “The MLTS is a ground-breaker because it’s an affordable way to tin the leads of fine-pitch QFPs without bridging. No more sending them out to be done somewhere else at high cost, with attendant shipping delays and lead times. Now they can be done ‘right at home’ under house control quickly and reliably and for a fraction of the cost of outsourcing to someone else’s expensive machine.”

The new systems will be exhibited at IPC APEX EXPO 2012 in booth #1636. The Conference and Exhibition takes place February 28-March 1 at the San Diego Convention Center in San Diego, California.

The new KISS-205, a fully configured in-line SMEMA-compatible selective soldering system effectively splits the process of fluxing, pre-heating, and soldering to significantly gain productivity by reducing TAKT by up to 50% versus incremental processing. “In the KISS-205, a PCB is fluxed and brought to preheat temperature, then sent to the second conveyor for soldering while concurrently applying flux and pre-heating the next PCB,” Cable states. “The bottom line result is that the KISS-205 is twice as fast as a conventional machine. Simply stated, the key advantages of the KISS 205 are speed and process control.”

Effects of critical parameters on solder deposition

Factiva: "The purpose of this paper is to comprehensively explore the effects of critical parameters on solder deposition and to establish a systematic approach for determining guidelines for solder paste inspection (SPI) workstations. Design/methodology/approach - This study explored the effects of process parameters, stencil and printed circuit board designs on solder deposition and identified the major post-reflow defect scenarios," scientists in Taipei, Taiwan report.

Special edition of Mat Trans on Lead-Free for November 2012

From: Katsuaki Suganuma [mailto:suganuma@sanken.osaka-u.ac.jp]
Sent: 11 November 2011 04:51
To: suganuma@sanken.osaka-u.ac.jp
Subject: Submission invitation to MaterTrans special issue on lead-free and advanced interconnection

Dear Sir:

We are happy to inform you that our journal Materials Transactions (The Japan Institute of Metals) will publish a special issue on Lead-Free and Advanced Interconnection Materials for Electronics V as November 2012 .
You will find the announcement on the issue and the instruction of preparation in the following.

Announcement:10 years have passed since lead-free transition in electronics 　
                        interconnection. Lead-free interconnection has become one
                        of the indispensable technologies not only in consumer
                        electronics industries but also wider areas including
                        automotive, power electronics, aeronautic, LED lighting
                        and renewable energies, in which higher reliability
                        becomes essential. In addition, ultra heat-resistant
                        interconnection materials beyond 200 oC are required for
                        the establishment of wide band gap semiconductors such as
                        SiC and GaN. Those interconnection materials will involve
                        high temperature lead-free solders, conductive adhesives,
                        nano/micron particle sintering bonding, and nano solders.
                        In the current 5th special issue, the papers focused on
                        new interconnection materials are widely invited. New
                        scientific findings and technology development will be
                        demonstrated. Thus, this special issue will provide great
                        insight to the readers working in the field of the
                        advanced interconnection engineering.

Topics: Tin whisker, Electromigration, High temperature solder alternatives,
　　　　Conductive adhesives, Die-attach, TSV, wafer bonding, Plating,
            Microstructure and phase stability, Interface reactions, Reliability,
            Mechanical properties of solders and joints, Wetting phenomena,
            Corrosion, oxidation and ion-migration, Soldering processes and
            fine pitch assembly, Materials in soldering process, Environmental
            impacts and recycling

Instruction of preparation

Bylaws for Contribution to Materials Transactions http://www.sendai.kopas.co.jp/METAL/rule.html

Manuscript Instructions
http://www.sendai.kopas.co.jp/METAL/point.html

Application form
http://jim.or.jp/cgi-bin/jim/kaigaieentry.cgi

We would be very pleased if you would contribute an original paper (Regular Article) to the issue.

Contributors will bear part of the cost for publication. Contributors will be presented 50 reprints free.

Please register in the Application Form Page if you will contribute your paper.

Manuscripts due is June 1, 2012.


Sincerely yours,

Prof. S. Miyazaki
Chairperson
Mater. Trans.
FAX:   +81-22-223-6312
E-mail: editjt@jim.or.jp

Advanced Interconnections intros solder preform terminals

Connector Specifier: "The solder preform now available from Advanced provides a predictable percent of fill and eliminates extra processing steps. The company notes that using a solder preform can often reduce total system processing costs by eliminating the need for wave soldering, solder fountains, or additional solder stencil steps associated with intrusive reflow or pin-in-paste processes."

Sn coated Cu nanoinks

Factiva: "The deposition of tin-clad nano-size copper particles was carried out by means of ink-jet printing. Curing the particles on Polyimide (PI) turned them into soldered structures using an Nd-YAG laser,' scientists in Hong Kong, People's Republic of China report.

'Area coverage of 55% was achieved for a single-layer print. Subsequent laser sintering increased this value to 95%. A Butanol-based copper ink and an aqueous tin (Sn)-clad Copper (Cu) ink were produced and were ink-jetted in this work. These nano-metallic inks showed excellent suspension stability with particle weight concentrations as high as 5%. The ink components were examined by measuring the particle size distribution in a dispersed condition, and the melting temperature. A piezo ink-jet print head was used to deposit the inks onto a moveable substrate. The thermal effect of the laser irradiation allowed approaching and connecting adjacent particles by melting the particle's tin coating"

Improvement of flux-less, lead-free solder wettability on CF4-plasma-fluorinated Sn and Ag

Scopus: "Atmospheric pressure non-equilibrium plasma inducted CF4 gas was irradiated to Sn and Ag substrates to obtain fluorinated Sn and Ag surfaces with a high affinity of a lead-free solder without fluxes. The plasma was produced by applying microwave power inducted with Ar-CF4-O2 mixed gases. The plasma irradiation successfully fluorinates the metal surfaces completed within 15min.

The fluorinated metal surfaces were observed using a scanning electron microscopy (SEM) and analyzed using an X-ray photoelectron spectroscopy (XPS). The Sn and Ag surfaces were covered mainly with SnF2 and AgF2 through the plasma irradiation respectively. The contact angle of the solder mounted on the metal substrates was measured to evaluate the wettability. The contact angle was minimized at the flow ratio of CF4/O2 which was 1/9. Surface fluorination by non-equilibrium plasma irradiation would be applicable to improve the wettability of flux-less solder"

Technology could help firms overcome high tin cost

Steel Guru: "Mitch Holtzer, Cookson's director for assembly materials, said that technological developments have the potential to cut consumption of tin a metal for which it is difficult to find substitutes, without disrupting the solder market. He cited the use of nitrogen in the soldering process, which prevents tin from oxidising and therefore reduces waste, which he said, could be a solution for cutting costs.

He said that at some point nitrogen becomes inexpensive enough to use that it's a net saving for the user to pump nitrogen across the solder. Selective soldering machines, which are much smaller units that consume less solder and generate less scrap, are also coming on the market. We've seen quite a significant reduction for demand for bar solder because of this selective trend."

Even so, the long-term future for the use of tin in electronic solders is fundamentally sound, in part because of the billions of dollars invested in the infrastructure of electronics assembly, he said.

Also a 40 percent jump in silver prices this year could benefit tin. Spot silver was last indicated at $23.59 an ounce.

"If you substitute tin for silver, that does bring down the cost of solders dramatically. We see a very rapid trend (developing) in that area, which could begin next year," said Holtzer, adding that the silver content could be reduced from 3 percent to as little as 0.3 percent.

Improvement of flux-less, lead-free solder wettability

Scopuss: "Atmospheric pressure non-equilibrium plasma inducted CF4 gas was irradiated to Sn and Ag substrates to obtain fluorinated Sn and Ag surfaces with a high affinity of a lead-free solder without fluxes.

The plasma was produced by applying microwave power inducted with Ar-CF4-O2 mixed gases. The plasma irradiation successfully fluorinates the metal surfaces completed within 15 min. The fluorinated metal surfaces were observed using a scanning electron microscopy (SEM) and analyzed using an X-ray photoelectron spectroscopy (XPS). The Sn and Ag surfaces were covered mainly with SnF2 and AgF2 through the plasma irradiation respectively.

The contact angle of the solder mounted on the metal substrates was measured to evaluate the wettability. The contact angle was minimized at the flow ratio of CF4/O2 which was 1/9. Surface fluorination by non-equilibrium plasma irradiation would be applicable to improve the wettability of flux-less solder"

Selective soft laser soldering

OptoIQ: "With regard to peel force and contact resistance, the quality of the laser soldered joints exceeds that of other contacting technologies. The peel force is higher by a factor of 3, whereas the thermal resistance is only about 14% of the contact solder joint.

DILAS, the diode laser company, is focused on delivering the most innovative technologies and advanced product solutions for the industrial market. Diode-based laser soldering is one example.

For further information, please contact Dave MacLellan, sales manager, Micro Division, Rofin-Baasel UK Limited, sales@rofin-baasel.co.uk."