Printed Circuit Design & Fab - July 2008 - (Page 33) EMERGING TECHNOLOGIES p Discontinuous change in properties due to size effects p y g g Particle Size FIGURE 1. The tipping point in properties found in many materials at the nanoscale. FIGURE 2. Conductive network produced using heat-treated 80 nm silver. and normally occurs below 100 nm (FIGURE 1). Solder materials containing nanosized metals exploit the high surface area and high surface energy (think of it as stored energy) of nano-sized particles to lower the apparent melting point below the conventional melting point. Thus the melting points of tin, silver and copper, the ingredients of most popular Pb-free solders, all can be depressed below 200°C, well below the eutectic melting point of 217°C.7 Silver exhibits a dramatic increase in sinterability at temperatures below 200°C. Nano-silver powders can be produced in essentially monodisperse form using a “bottom-up” approach, in which nuclei grow under a protective polymer coat that permits metal atoms to accumulate, while acting as a charge director to keep the embryo crystals separated. The crystals are permitted to grow until the desired particle size is achieved; then the reaction is stopped and the crystals suspended in an appropriate vehicle or dried. The polymer FIGURE 3. Resistivity as a function of process temperature for a 30 nm silver. Note the significant increase in conductivity as low as 125°C. coating, which can be made hydrophilic or hydrophobic, aids re-dispersion and prevents spontaneous sintering of the dried silver particles. Pure nano-metals such as silver can be deposited by a range of printing techniques with a thermally removable binder. Even at 80 nm, significant densification and conductivity development is seen above 125°C (FIGURES 2 and 3). These show promise for die attach, conductor printing and electrical connections. December 2-4, 2008 Orlando Metropolitan Resort Orlando, FL www.pcbshows.com/orlando Interested in exhibiting? An exciting addition to the PCB Shows portfolio of events for designers and fabricators Bringing you the best of our renowned and respected conferences and seminars to Orlando, FL Featuring • 3-day targeted technical conference • 1-day tabletop exhibition • Great networking opportunities Brought to you by JULY 2008 PRINTED CIRCUIT DESIGN & FAB 33 http://www.pcbshows.com/orlando http://www.pcbshows.com/orlando http://www.upmediagroup.com
Table of Contents Feed for the Digital Edition of Printed Circuit Design & Fab - July 2008 Printed Circuit Design & Fab - July 2008 Printed Circuit Design & Fab - July 2008 - (Page Cover1) Printed Circuit Design & Fab - July 2008 - (Page Cover2) Printed Circuit Design & Fab - July 2008 - (Page 1) Printed Circuit Design & Fab - July 2008 - (Page 2) Printed Circuit Design & Fab - July 2008 - (Page 3) Printed Circuit Design & Fab - July 2008 - (Page 4) Printed Circuit Design & Fab - July 2008 - (Page 5) Printed Circuit Design & Fab - July 2008 - (Page 6) Printed Circuit Design & Fab - July 2008 - (Page 7) Printed Circuit Design & Fab - July 2008 - (Page 8) Printed Circuit Design & Fab - July 2008 - (Page 9) Printed Circuit Design & Fab - July 2008 - (Page 10) Printed Circuit Design & Fab - July 2008 - (Page 11) Printed Circuit Design & Fab - July 2008 - (Page 12) Printed Circuit Design & Fab - July 2008 - (Page 13) Printed Circuit Design & Fab - July 2008 - (Page 14) Printed Circuit Design & Fab - July 2008 - (Page 15) Printed Circuit Design & Fab - July 2008 - (Page 16) Printed Circuit Design & Fab - July 2008 - (Page W1) Printed Circuit Design & Fab - July 2008 - (Page W2) Printed Circuit Design & Fab - July 2008 - (Page W3) Printed Circuit Design & Fab - July 2008 - (Page W4) Printed Circuit Design & Fab - July 2008 - (Page W5) Printed Circuit Design & Fab - July 2008 - (Page W6) Printed Circuit Design & Fab - July 2008 - (Page W7) Printed Circuit Design & Fab - July 2008 - (Page W8) Printed Circuit Design & Fab - July 2008 - (Page W9) Printed Circuit Design & Fab - July 2008 - (Page W10) Printed Circuit Design & Fab - July 2008 - (Page W11) Printed Circuit Design & Fab - July 2008 - (Page W12) Printed Circuit Design & Fab - July 2008 - (Page W13) Printed Circuit Design & Fab - July 2008 - (Page W14) Printed Circuit Design & Fab - July 2008 - (Page W15) Printed Circuit Design & Fab - July 2008 - (Page W16) Printed Circuit Design & Fab - July 2008 - (Page 17) Printed Circuit Design & Fab - July 2008 - (Page 18) Printed Circuit Design & Fab - July 2008 - (Page 19) Printed Circuit Design & Fab - July 2008 - (Page 20) Printed Circuit Design & Fab - July 2008 - (Page 21) Printed Circuit Design & Fab - July 2008 - (Page 22) Printed Circuit Design & Fab - July 2008 - (Page 23) Printed Circuit Design & Fab - July 2008 - (Page 24) Printed Circuit Design & Fab - July 2008 - (Page 25) Printed Circuit Design & Fab - July 2008 - (Page 26) Printed Circuit Design & Fab - July 2008 - (Page 27) Printed Circuit Design & Fab - July 2008 - (Page 28) Printed Circuit Design & Fab - July 2008 - (Page 29) Printed Circuit Design & Fab - July 2008 - (Page 30) Printed Circuit Design & Fab - July 2008 - (Page 31) Printed Circuit Design & Fab - July 2008 - (Page 32) Printed Circuit Design & Fab - July 2008 - (Page 33) Printed Circuit Design & Fab - July 2008 - (Page 34) Printed Circuit Design & Fab - July 2008 - (Page 35) Printed Circuit Design & Fab - July 2008 - (Page 36) Printed Circuit Design & Fab - July 2008 - (Page 37) Printed Circuit Design & Fab - July 2008 - (Page 38) Printed Circuit Design & Fab - July 2008 - (Page 39) Printed Circuit Design & Fab - July 2008 - (Page 40) Printed Circuit Design & Fab - July 2008 - (Page 41) Printed Circuit Design & Fab - July 2008 - (Page 42) Printed Circuit Design & Fab - July 2008 - (Page 43) Printed Circuit Design & Fab - July 2008 - (Page 44) Printed Circuit Design & Fab - July 2008 - (Page 45) Printed Circuit Design & Fab - July 2008 - (Page 46) Printed Circuit Design & Fab - July 2008 - (Page 47) Printed Circuit Design & Fab - July 2008 - (Page 48) Printed Circuit Design & Fab - July 2008 - (Page Cover3) Printed Circuit Design & Fab - July 2008 - (Page Cover4)
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