FLIP CHIP ULTRASONIC GOLD TO GOLD INTERCONNECT FOR SMALLDIE WITH HIGH BUMP COUNT

摘要

Flip Chip ultrasonic gold to gold interconnect (GGI) hasrnprovided a lead free, no clean, process solution for devicesrnwith bump counts under thirty for the past five years. Thernproven reliability and manufacturing cost savings ofrnultrasonic GGI bonding has now expanded to include largerndie sized up to 10mm2 with bump counts up to one hundred.rnThe mounting accuracy of the GGI process is +/- 10 μm.rnThe availability of a voice coil motor with 100N loadrncapability and improved ultrasonic control has allowed forrnthe performance improvement in ultrasonic GGI bonderrnequipment for fine pitch high bump die bonding.rnImproved devices using GGI CSP packaging such as sensor,rnRF, memory, and HB LED can now use the 100N ultrasonicrnGGI process.rnUltrasonic GGI bonders use a built in monitoring functionrnfor each die bond. Collapse height and impedance can bern“mapped” for each die bond location in real time. Using thernbuilt in process each die location characteristics can bernmapped. The map data is stored as a monitor text log filernfor easy access by other windows based programs.rnGold bonds provide superior bond strength because of thernmonolithic structure of the gold material. Gold bonds alsornhave superior high frequency performance and lowrnresistance when compared to solder or conductive materials.rnDie size reductions are achieved with flip chip ultrasonicrnGGI process when compared to wire bonding. The GGIrnultrasonic GGI process reliably handles gold bump pitchesrnof 100 μm or less in high volume manufacturing. Thisrnprocess capability has allowed die size reductions up to 70%rnwhen compared to wire bonding or C4 solder flip chiprnprocess.rnFlip Chip ultrasonic GGI process can bond die withrnthickness as thin as 100 μm. This has been an importantrnbenefit for mobile products where low profile is critical.rnLow cost organic substrate materials and embedded passivernLTCC substrates are used in flip chip ultrasonic GGI devicernmanufacturing. Because the GGI ultrasonic GGI processrnrelies on solid phase welding of the die to the substrate,rnrelatively low bonding temperatures ＜150℃ is usedrnallowing it to be an excellent choice for substrate materialsrnsensitive to heat.