DocumentCode :
2378493
Title :
Comparative compliance of a representative surface mount leadless solder connection and commercial lead designs
Author :
Kotlowitz, Robert W. ; Rizzo, Anthony R.
Author_Institution :
Network Wireless Syst. Bus. Unit, AT&T Bell Labs., Whippany, NJ, USA
fYear :
1994
fDate :
1-4 May 1994
Firstpage :
94
Lastpage :
101
Abstract :
The long-term reliability of surface mount (SM) solder interconnections remains an important issue in many critical electronics packaging applications. Compliant leads are typically post-attached to leadless ceramic chip carriers (LCCCs) and multichip modules (MCMs) to enhance the SM attachment reliability margin on organic substrates. The various lead-forms are commercially available in edge-clip, soldered, and thermocompression (TC) bonded designs for component attachment. Compliance evaluation was performed for a representative corner-most solder connection on a LCCC. The effective stiffness of the solder joint and commercial post-attached lead designs were compared in order to demonstrate the SM interconnection reliability advantage provided by certain edge-clip and TC-bonded lead-forms. Commercial high-compliance edge-clip, soldered, and TC-bonded lead designs have diagonal-direction stiffness between nominally 10-40 lb/in, prior to circuit-board attachment. The compliant leads accommodate a large part of the component-substrate thermal expansion mismatch, significantly reducing the cyclic loads transmitted to the comparatively noncompliant solder connections. The diagonal stiffness results for the corner-most solder joint are specific for the particular contour and dimensions of the FE structural model. However, the current study provides fundamental understanding of the compliance advantage of post-attached leads compared to leadless SM interconnections
Keywords :
finite element analysis; integrated circuit interconnections; integrated circuit packaging; integrated circuit reliability; lead bonding; multichip modules; soldering; surface mount technology; FE structural model; SM attachment reliability margin; SM interconnection reliability; TC-bonded lead-forms; commercial lead designs; compliant leads; component-substrate thermal expansion mismatch; corner-most solder connection; diagonal-direction stiffness; effective stiffness; electronics packaging; high-compliance edge-clip; leadless ceramic chip carriers; long-term reliability; multichip modules; surface mount leadless solder connection; thermocompression bonded designs; Bonding; Ceramics; Electronics packaging; Integrated circuit interconnections; Lead; Multichip modules; Performance evaluation; Samarium; Soldering; Thermal expansion;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Electronic Components and Technology Conference, 1994. Proceedings., 44th
Conference_Location :
Washington, DC
Print_ISBN :
0-7803-0914-6
Type :
conf
DOI :
10.1109/ECTC.1994.367645
Filename :
367645
Link To Document :
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