DocID024463 Rev 2

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TN0991

Package description

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Package description

1.1

Overview

STMicrolectronics WLCSP are manufactured with a wafer level process by attaching solder

balls on I/Os pads of the active wafer side, thus allowing bumped dice to be produced. The

I/O contacts can be either configured as a matrix or located in the periphery. A redistribution

layer is used.

Lead-free balls are manufactured using SAC (SnAgCu) alloy with a near-eutectic melting

point ranging 217 to 221 °C. This material makes the package compatible with standard

reflow processes.

The ball diameter allows to use pick-and-place process compatible with existing equipment,

in particular with equipment used for ball grid array (BGA) packages. It also makes it

compatible with the PCB design rules used for standard ICs.

The devices available in WLCSP are delivered in tape and reel packing with the bumps

turned down (placed on the bottom of the carrier tape cavity). The other face of the device is

flat and allows picking it as for standard SMD packages.

Caution:

It is recommended to handle WLCSPs with care since they are built on a silicon substrate

and are not protected against aggressive actions.

WLCSP Devices are 100 % electrically tested

.

The device references are marked on the top flat side of the device (see Figure 1).

Figure 1. WLCSP bump views