Identification of antistatic packaging material as a source of circuit board contamination

Technical Report · Fri Jul 01 00:00:00 EDT 1988

OSTI ID:6669029

Rodacy, P J; Burns, F B; Ward, K J

Circuit boards to be used in satellites were shipped to Sandia in Richmond RCAS 4200 ESD shielding bags. Upon inspection under low magnification, a white fuzzy deposit was observed on many of the solder joints. Preliminary examination using Fourier transform infrared (FT-IR) microspectroscopy identified the material as a metal salt of a long chain aliphatic carboxylic acid. The material was definitively identified as a mixture of lead di(n-octanoate) and tin di(n-octanoate) using mass spectrometry. These compounds were formed by the reaction of octanoic acid with the lead/tin solder. We have demonstrated that the solder is mechanically weakened by the formation of these compounds. Investigation has shown that the Richmond RCAS 4200 ESD shielding bags contain octanoic acid in sufficient quantities to form visually detectable quantities of lead di(n-octanoate) and tin di(n-octanoate) in less than 90 days at room temperature. Ameri-Stat Static Shield and Dow Chemical CHIPLOC ES antistatic bags do not contain carboxylic acids, and solder samples stored in these bags for several months do not exhibit evidence of lead di(n-octanoate) or tin di(n-octanoate) formation. Users of static shielding bags should be aware that the use of static shielding bags can be harmful to solder joints. Steps should be taken to ensure that all antistatic packaging in use is free from carboxylic acid contamination. 3 refs., 6 figs., 1 tab.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6669029
• Report Number(s): SAND-88-0614; ON: DE89001007
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
ELECTROSTATIC CHARGE ELIMINATORS
CONTAMINATION
SOLDERED JOINTS
FAILURES
CARBOXYLIC ACIDS
CONTAINERS
ELECTRONIC CIRCUITS
NUMERICAL DATA
PACKAGING
DATA
INFORMATION
JOINTS
ORGANIC ACIDS
ORGANIC COMPOUNDS
360604* - Materials- Corrosion
Erosion
& Degradation
420800 - Engineering- Electronic Circuits & Devices- (-1989)