PCF8576DTSLASH2 datasheet(46/52 Pages) NXP

46 / 52 page

PCF8576D_7

Product data sheet

Rev. 7 — 18 December 2008

46 of 52

NXP Semiconductors

PCF8576D

Universal LCD driver for low multiplex rates

For further information on temperature proﬁles, refer to Application Note

AN10365

“Surface mount reﬂow soldering description”.

18. Soldering of WLCSP packages

18.1 Introduction to soldering WLCSP packages

This text provides a very brief insight into a complex technology. A more in-depth account

of soldering WLCSP (Wafer Level Chip-Size Packages) can be found in application note

AN10439 “Wafer Level Chip Scale Package” and in application note AN10365 “Surface

mount reﬂow soldering description”.

Wave soldering is not suitable for this package.

All NXP WLCSP packages are lead-free.

18.2 Board mounting

Board mounting of a WLCSP requires several steps:

1. Solder paste printing on the PCB

2. Component placement with a pick and place machine

3. The reﬂow soldering itself

18.3 Reﬂow soldering

Key characteristics in reﬂow soldering are:

• Lead-free versus SnPb soldering; note that a lead-free reﬂow process usually leads to

higher minimum peak temperatures (see Figure 32) than a PbSn process, thus

reducing the process window

MSL: Moisture Sensitivity Level

Fig 31. Temperature proﬁles for large and small components

001aac844

temperature

time

minimum peak temperature

= minimum soldering temperature

maximum peak temperature

= MSL limit, damage level

peak

temperature

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