Recommended storage, shipping instructions and descriptions

AN1235

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Doc ID 7272 Rev 8

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Recommended storage, shipping instructions and

descriptions

handling, reels are packed in a cardboard box.

STMicroelectronics thus recommends the following shipping and storage conditions:

●

Relative humidity between 15% and 70%

●

Temperature range from -55 °C to +150 °C

Components in a non opened sealed bag can be stored 6 months after shipment.

Components in tape and reel must be protected from exposure to direct sunlight.

Moisture sensitivity level (MSL as per JEDEC J-STD-020C) is not applicable to Flip-Chip

devices since there is no plastic encapsulation and so no risk of moisture absorption and

possible related package cracks.

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Soldering assembly recommendations

5.1

PCB design recommendations

For optimum electrical performance and highly reliable solder joints, STMicroelectronics

recommends the PCB design guidelines listed in Table 3.

To optimize the natural self centering effect of Flip Chips on PCB, PCB pad positioning and

size have to be properly designed.

Note:

A too thick gold layer finishing on the PCB pad is not recommended (low joint reliability).

Micro vias

An alternative to routing on the top surface is to route out on buried layers. To achieve this,

the pads are connected to the lower layers using micro vias.

Table 3.

PCB design recommendations.

PCB pad design

Non solder mask defined

Micro via under bump allowed

PCB pad size

Ø = 300 µm max. (circular) - 250 µm recommended

Solder mask opening

Ø = 340 µm min. (for 300 µm diameter pad)

PCB pad finishing

Cu - Ni (2-6 µm) - Au (0.2 µm max) oc Cu OSP (Organic Substrate

Protection)