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CornerBond一点资料

最近遇到一些cornerbond用途的客户,上网找了找发现现在关于cornerbond和edgebond的资料还是挺多的,提供一个资料供大家学习。
Corner Bonding of CSPs: Processing and Reliability
Guoyun Tian, Yueli Liu, R. Wayne Johnson,
Pradeep Lall, Mike Palmer, & Nokib Islam
Laboratory for Electronics Assembly &
Packaging – Auburn University
162 Broun Hall, ECE Dept.
Auburn, AL 36849 USA
334-844-1880
johnson@eng.auburn.edu
Larry Crane
Henkel Loctite Corporation
Loctite Electronic Materials
Industry, CA
800-827-2207 x401
Larry_Crane@loctite.com
ABSTRACT
The use of CSPs has expanded rapidly, particularly in portable electronic products. Many CSP designs
will meet the thermal cycle or thermal shock requirements for these applications. However, mechanical
shock (drop) and bending requirements often necessitate the use of underfills to increase the mechanical
strength of the CSP-to-board connection. Capillary flow underfills processed after reflow, provide the most
common solution to improving mechanical reliability. However, capillary underfill adds board dehydration,
underfill dispense, flow and cure steps and the associated equipment to the assembly process.
Corner bonding provides an alternate approach. Dots of underfill are dispensed at the four corners of
the CSP site after solder paste print, but before CSP placement. During reflow the underfill cures, providing
mechanical coupling between the CSP and the board at the corners of the CSP. Since only small areas of
underfill are used, board dehydration is not required.
This paper examines the manufacturing process for corner bonding including dispense volume, CSP
placement and reflow. Drop test results are then presented. A conventional, capillary process was used for
comparison of drop test results. Test results with corner bonding were intermediate between complete
capillary underfill and non-underfilled CSPs. Finite element modeling results for the drop test are also
included.

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