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Metro ChapterRegion: Metropolitan New York/Long Island
Future Meeting Information
METRO Chapter Dinner Presentation on Wednesday February 25, 2009 Wire Bonding Semiconductor Devices for Metallurgists Featuring: Lee Levine Process Solutions Consulting 8009 George Road, New Tripoli, Pa 18066
Program Info: In 2008 more than 1013 semiconductor interconnects will be formed. Of this quantity, more than 90% will be produced by wire bonding. Wire bonding is a high speed, ultrasonic welding process. In the more common variation, ball bonding, fine diameter (average diameter is now < 25m m) gold or copper wire is welded to a thin (1m m) Al-1%Si-0.5%Cu bond pad on the semiconductor device. Typical bond pads are now < 75m m square and devices like graphic processors may have more than 1000 on a single device. State-of-the-art bonders now operate at rates > 16 wires/second (32 welds + high speed motions between the two welds that define each wire). Placement accuracy must be better than ± 2.5m m. Yet for all that the wires are a small fraction of the diameter of a hair (100m m) and the speed is high, the process is a welding process and must be understood from a metallurgical perspective. At the start of the process, formation of a ball on the tip of the wire by a spark from the Electronic Flame Off (EFO) is a melting/casting process. Thermal transfer to solidify the ball is >90% up the wire and the grains are clearly columnar, with a few equiaxed grains at the very bottom tip of the ball (the last region to solidify). The influence of ultrasonics on metals has been shown to significantly change the physical properties, lowering the flow stress and Young’s Modulus, allowing both easy flow of slip planes with massive plastic deformation of the ball and also significant deformation of the underlying bond pad. Gold bonding wire is normally 99.99% (4-9’s, 100 ppm total impurities) pure and is produced by refining gold to 5-9’s purity, and alloying within the 100ppm allowable impurity range. Absolute control of the alloying is required to allow the dynamics of high-speed loop formation (Z- axis accelerations of >300 g’s) without loss of control or damage to the wire. Intermetallic formation in the Au-Al and Cu-Al systems has been widely studied and much work has gone into controlling distribution of phases. The use of copper ball bonding is growing rapidly, especially in the larger wire diameter applications where the replacement of Au by Cu provides a large cost advantage. Copper has some advantages (cost, conductivity, stiffness) but it is also harder mechanically and can cause damage to the underlying Si, is more difficult to bond (the intermetallic has a much lower growth rate) and requires a reducing atmosphere to eliminate oxidation .
Speaker Bio:
Lee is a consultant for Process Solutions Consulting where he provides process engineering consultation and SEM/EDS analysis. Lee’s previous experience includes 20 years as Principal and Staff Metallurgical Process Engineer at Kulicke & Soffa and Distinguished Member of the Technical Staff at Agere Systems. He has been awarded 4 patents, published more than 50 technical papers, and in 1999 won the John A. Wagnon Technical Achievement award from the International Microelectronics and Packaging Society (IMAPs). Major innovations include copper ball bonding, loop shapes for thin, small outline packages (TSOP and TSSOP, and CSPs) and introduction of DOE and statistical techniques for understanding semiconductor assembly processes. He is an IMAPs Fellow, V.P of the Keystone Chapter, and V.P Technology for IMAPS. In addition he is a senior member of IEEE.Lee is a graduate of Lehigh University, Bethlehem, Pa where he earned a degree in Metallurgy and Materials Engineering. Logistics and Registration: Holiday Inn Ronkonkoma – Click here for Directions3845 Veterans Highway Ronkonkoma, NY 11779 631-585-9500
Registration/Networking 5-6:30 PM Dinner Buffet: 6:30-7:15 PM Presentation: 7:15-8:15 PM
Price: Members: $25.00 if Pre-Registered by February 25, 2009. $50.00 after February 25, 2009 Non-Members: $50.00 if Pre-Registered by February 25, 2009. $75.00 After February 25, 2009 Student Members: Free if Pre-Registered by February 25, 2009. $25.00 February 25, 2009 Due to the anticipated large turnout, we will be giving preference to members. Please provide your membership number when registering. If you wish to join membership information is available at www.imaps.orgPre Registration Email: metroimaps@optonline.net , Phone: Steve Lehnert (631) 379-8239WEB: www.imaps.org/chapters/metro
Chapter Information
On December 4th METRO Chapter had a Holiday Party for members and guests. The event was well attended with all the guests commenting about what a great time they had. There were door prizes donated by Lyons and Associates, GSA Optimum, Q-Source and the Chapter itself. The highlight of the evening was when the chapter presented $1000.00 Scholarship awards to Tim Resig and Christian Grigoleit both charter members of the student Chapter at SUNY Farmingdale. The chapter would like to extend special thanks to Kevin Carmody and the staff of KC Party Entertainment for the donation of the DJ and equipment.
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Chapter Officers President: Mike McKeown Orthodyne Phone: 516 739 2690 Email: Mike.McKeown@orthodyne.net Technical: Finance: Arrangements:
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