Assessment of circuit board surface finishes for electronic assembly with lead-free solders

Conference · Tue Oct 01 04:00:00 EDT 1996

OSTI ID:378903

Ray, U; Artaki, I; Finley, D W; Wenger, G M ^[1]; Pan, T; Blair, H D; Nicholson, J M ^[2]; Vianco, P T ^[3]

---

1. Bell Labs., Princeton, NJ (United States). Lucent Technologies
2. Ford Motor Co., Dearborn, MI (United States)
3. Sandia National Labs., Albuquerque, NM (United States)

The suitability of various metallic printed wiring board surface finishes was assessed for new technology applications that incorporate assembly with Lead-free solders. The manufacture of a lead-free product necessitates elimination of lead (Pb) from the solder, the circuit board as well as the component lead termination. It is critical however for the selected interconnect Pb-free solder and the corresponding printed wiring board (PWB) and component lead finishes to be mutually compatible. Baseline compatibility of select Pb-free solders with Pb containing PWB surface finish and components was assessed. This was followed by examining the compatibility of the commercially available CASTIN{trademark} (SnAgCuSb) Pb-free solder with a series of PWB metallic finishes: Ni/Au, Ni/Pd, and Pd/Cu. The compatibility was assessed with respect to assembly performance, solder joint integrity and long term attachment reliability. Solder joint integrity and mechanical behavior of representative 50 mil pitch 20I/O SOICs was determined before and after thermal stress. Mechanical pull test studies demonstrated that the strength of SnAgCuSb solder interconnections is notably greater than that of SnPb interconnections.

• Research Organization: Sandia National Labs., Albuquerque, NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 378903
• Report Number(s): SAND--96-2265C; CONF-9609212--4; ON: DE96014884
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
ANTIMONY ALLOYS
BRAZING ALLOYS
COATINGS
COMPATIBILITY
COPPER
COPPER ALLOYS
EVALUATION
FAILURES
GOLD
MECHANICAL TESTS
MICROSTRUCTURE
NICKEL
PALLADIUM
PERFORMANCE
PRINTED CIRCUITS
RELIABILITY
SILVER ALLOYS
SOLDERED JOINTS
SURFACE FINISHING
TIN ALLOYS