Sonoscan imaging permits bonded wafer rework

Microelectronics International

ISSN: 1356-5362

Article publication date: 1 December 2001




(2001), "Sonoscan imaging permits bonded wafer rework", Microelectronics International, Vol. 18 No. 3.



Emerald Group Publishing Limited

Copyright © 2001, MCB UP Limited

Sonoscan imaging permits bonded wafer rework

Sonoscan imaging permits bonded wafer reworkKeywords: Sonoscan, Bonding, Imaging

Users of the Sonoscan's new AW2000 system for automated bonded wafer inspection report that susbtantial economies are realized by separating, cleaning, and re-bonding defective wafer pairs.

Handling wafers up to eight inches in diameter, the automated system images bonded wafers for particles and other defects between the wafers. Field reports show that the system is especially useful in imaging wafers after initial Van der Waals bonding. After this process, the wafers are joined only by weak chemical forces, and can easily be separated. Separated wafers are cleaned and rebonded.

Inspection at this point avoids further processing of defective wafer pairs and greatly increases yield with a minimum of rework. Automated acoustic imaging also serves as a process monitor for the initial bonding step. The system classifies inspected wafers according to the user's criteria, and is capable of imaging defects having sizes as small as 5 to 10 microns. If needed, acoustic imaging can also be performed after annealing and after thinning.

For more information about the AW2000, contact: Steven R. Martell, technical marketing manager, Sonoscan, Inc. E-mail:; Tel: 847 437 6400; ext: 240; Fax: 847 437 1550.

Related articles