DocID14016 Rev 4

7/15

AN2639

Soldering

4.2

Soldering recommendations

The following recommendations must be followed for soldering each package type (see

Table 2).

4.3

Compatibility with leaded soldering process

Lead-free packages can be assembled using leaded soldering process. For more details

about soldering process compatibilities and conditions, please refer to application note

AN2034.

1. Reflow soldering with DIP and wave soldering with PLCC, BGA, VFQFPN, UFQFPN, and WLCSP are

strictly impossible due to the lead/ball configuration.

Package

Reflow processing process

Wave soldering process

Process

Reliability

Process

Reliability

PLCC

OK

OK

impossible

N/A

SOP

OK

OK

feasible

(2)

2. Wave soldering with SMT packages is not recommended because the thermal shock associated with

package body solder dipping may induced internal structural damage to the package (interface

delamination) that may affect long term reliability.

SMT Package characterizations performed as a standard by STMicroelectronics only include Solder

Reflow Resistance assessment.

JEDEC JESD22A111 recommends that wave soldering of SMT packages should be evaluated by the

USER, because the stress induced inside the package is very dependant of solder process parameters.

QFP

OK

OK

3. Wave soldering with PQFP is not recommended because it is difficult to avoid solder bridges when leads

pass through the double wave.

(2)

BGA

OK

OK

impossible

N/A

VFQFPN,

UFQFPN

OK

OK

impossible

N/A

WLCSP

OK

OK

impossible

N/A