TN-00-22: Micron Wire-Bonding Techniques Overview Technical Note Micron® Wire-Bonding Techniques Overview Bond-pads on Micron die may be either nickel-palladium (NiPd) or aluminum (Al), depending on product. This technical note provides guidance on wire bonding techniques for both types of bond pads. Manufacturing Guidelines Conventional wire-bonding equipment and techniques can be used with Ni-Pd and Al bond pads. While the bonding process is similar for the two pad types, Micron recommends different ultrasonic generator (USG) and force parameters, as shown in Table 1. Table 1: Example of Bonding Parameters Parameter Ni-Pd Al Wire type Platform Tip offset C/V USG profile USG current USG time Force USG pre-bleed Au K&S 5 0.3 Burst 130 10 8 10–25 Au K&S 5 0.3 Square or ramp 90 7 20 0–10 Unit mils mils/ms mA ms g % Wire size and ball diameter should be selected so the ball-bond remains entirely within the area of the bond pad. For any wire-bond interconnect system, the quality of the bond pad surface is key to achieving an acceptable non-stick-on-pad (NSOP) rate. Even small amounts of bond pad contamination can significantly impair the bonding process. To maintain bond pad integrity and to remove upstream assembly process contamination, Micron recommends a direct argon (Ar) gas flow without oxygen (O2) be used; and whenever possible, only bond once on a given pad. Studies indicate that an Ar plasma with O2 can cause bonding surfaces to oxidize, so O2 use is not recommended. Studies also indicate that prolonged exposure to plasma is unnecessary, and may even be detrimental due to redepositing of metals and organic material inside the plasma chamber. Micron recommends an Ar plasma preclean for 30 seconds or less (see Table 2). PDF: 09005aef844074cb/Source: 09005aef844074c4 tn0022_wire_bonding_techniques.fm - Rev. A 11/10 EN 1 Micron Technology, Inc., reserves the right to change products or specifications without notice. ©2010 Micron Technology, Inc. All rights reserved. TN-00-22: Micron Wire-Bonding Techniques Conclusion Table 2: Example of Plasma Clean Parameters Parameter Power Time Pressure Gas: Ar (O2 is not recommended) FBGA TSOP Unit 550 30 160 40 550 30 160 40 W s mTorr sccm Conclusion Micron’s NiPd or Al bond pads can be bonded with conventional wire bond equipment and techniques, but the process should be optimized to account for bond pad metallization and size. 8000 S. Federal Way, P.O. Box 6, Boise, ID 83707-0006, Tel: 208-368-3900 www.micron.com/productsupport Customer Comment Line: 800-932-4992 Micron and the Micron logo are trademarks of Micron Technology, Inc. All other trademarks are the property of their respective owners. PDF: 09005aef844074cb/Source: 09005aef844074c4 tn0022_wire_bonding_techniques.fm - Rev. A 11/10 EN 2 Micron Technology, Inc., reserves the right to change products or specifications without notice. ©2010 Micron Technology, Inc. All rights reserved. TN-00-22: Micron Wire-Bonding Techniques Revision History Revision History Rev. A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11/10 • Initial release. PDF: 09005aef844074cb/Source: 09005aef844074c4 tn0022_wire_bonding_techniques.fm - Rev. A 11/10 EN 3 Micron Technology, Inc., reserves the right to change products or specifications without notice. ©2010 Micron Technology, Inc. All rights reserved.