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No. Process Condition
5 Soldering 5-7. Sn-Zn solder
Sn-Zn solder affects product reliability.
Please contact TDK in advance when utilize Sn-Zn solder.
5-8. Countermeasure for tombstone
The misalignment between the mounted positions of the capacitors and the land
patterns should be minimized. The tombstone phenomenon may occur especially
the capacitors are mounted
(in longitudinal direction) in the same direction of the reflow
soldering.
(Refer to JEITA RCR-2335B Annex 1 (Informative) Recommendations to prevent the
tombstone phenomenon)
1)
2)
If an unsuitable cleaning fluid is used, flux residue or some foreign articles may
stick to chip capacitors surface to deteriorate especially the insulation resistance.
If cleaning condition is not suitable, it may damage the chip capacitors.
2)-1. Insufficient washing
(1)
(2)
(3)
Terminal electrodes may corrode by Halogen in the flux.
Halogen in the flux may adhere on the surface of capacitors, and lower the
insulation resistance.
Water soluble flux has higher tendency to have above mentioned
problems (1) and (2).
2)-2. Excessive washing
When ultrasonic cleaning is used, excessively high ultrasonic energy output
can affect the connection between the ceramic chip capacitor's body and the
terminal electrode. To avoid this, following is the recommended condition.
Power: 20 W/
max.
Frequency: 40 kHz max.
Washing time: 5 minutes max.
6 Cleaning
2)-3. If the cleaning fluid is contaminated, density of Halogen increases, and it may
bring the same result as insufficient cleaning.
7 Coating and
molding of the
P.C.board
1)
2)
3)
When the P.C.board is coated, please verify the quality influence on the product.
Please verify carefully that there is no harmful decomposing or reaction gas
emission during curing which may damage the chip capacitors.
Please verify the curing temperature.
