REACTIVITY OF NO-CLEAN PASTES AND FLUXES FOR THE SURFACE-MOUNT TECHNOLOGY PROCESS .2. CORROSION RISK MEASUREMENTS FOR PRINTED-CIRCUIT BOARDS AND SOLDER JOINTS
Pl. Cavallotti et al., REACTIVITY OF NO-CLEAN PASTES AND FLUXES FOR THE SURFACE-MOUNT TECHNOLOGY PROCESS .2. CORROSION RISK MEASUREMENTS FOR PRINTED-CIRCUIT BOARDS AND SOLDER JOINTS, Journal of electronic materials, 24(4), 1995, pp. 371-378
The introduction of no-clean pastes and fluxes for the surface mount t
echnology process needs testing methods of high sensitivity and reliab
ility to evaluate the activity of the residues after the reflow proces
s. An electrochemical method is proposed, suitable to ascertain the re
activity and the corrosion risk of these residues. Products of normal
use are tested, and their behavior described and compared. Surface mor
phologies and compositions are examined after reflow and after testing
. Local surface oxides are investigated with x-ray photoelectron spect
roscopy. Surface analytical results are interpreted and related to the
electrochemical behavior of solder joints. Tin is shown to have the m
ost important role toward the onset of possible localized corrosion.