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4 Notes on Storage and Mounting
4.1.4
Semiconductor Package Mount Manual
Wetting Time Temperature Dependence
This section presents an example of evaluation of the temperature dependence of wetting time.
When mounting electronic components on a printed wiring board, insufficient wetting may occur due to insufficient
heating during mounting.
Figures 4.5 and 4.6 show the results of investigating the temperature dependence of the wetting time listed in table 4.2,
Test Conditions.
Table 4.2
Meniscograph Test Conditions
Rosin  R Type
Flux
Sample
100-pin LQFP (Cu alloy)
Test temperature
See figures 4.5 and 4.6.
Immersion speed
15 mm/s
Immersion depth
0.15 mm
Immersion time
5s
Number of leads immersed
1
Number of tests
5
Storage conditions
100°C, 100%, 4 hours
Wetting time (seconds)
0.40
0.35
0.30
Sn
0.25
Sn-cu
0.20
Ni/Pd/Au
0.15
Sn-Pb
0.10
Sn-Bi
0.05
210
220
230
240
250
260
270
Melted solder temperature (˚C)
Figure 4.5 Wetting Time Temperature Dependence Evaluation Results (Sn-37Pb solder bath)
Page 88 of 140
R50ZZ0003EJ0500 Rev. 5.00
Feb 03, 2015