ZMXM-400 Series

Cooling Phase

A controlled cooling phase avoids unwanted metallurgical effects of the solder, and possible mechanical tensions in the

products. Controlled cooling helps achieve the brightest possible solder fillets with a good shape and low contact angle.

• Temperature fall rate: max 3ºC/sec

Pb-Free Soldering Paste

Use of “No Clean” soldering paste is strongly recommended, as it does not require cleaning after the soldering process.

The pastes listed in the examples below meet these criteria.

Soldering Paste: Indium 5.1 (Indium Corporation of America)

Alloy Specification: SAC305 - Sn Zinc 96.5%/Ag Silver 3.0%/Cu Copper 0.5%

Alloy Specification: SAC387 - Sn Zinc 95.5%/Ag Silver 3.8%/Cu Copper 0.7%

Melting Temperature: 217ºC

Soldering Paste: LFSOLDER TLF-206-93F (Tamura Kaken [UK] Ltd.)

Alloy Specification: Sn Zinc 95.5%/Ag Silver 3.9%/Cu Copper 0.6%

Melting Temperature: 216-221ºC

The final choice of the soldering paste depends on individual factory approved manufacturing procedures.

Stencil Thickness: 150 µm for host boards

Note:

The quality of the solder joints on the castellations (‘half vias’) where they contact the host board should meet

the appropriate IPC specification. See IPC-A-610-12.2.4.

PROCESSING (Continued)

Cleaning

In general, cleaning the populated modules is strongly discouraged. Residuals under the module cannot be easily removed

with any cleaning process.

• Cleaning with water can lead to capillary effects where water is absorbed into the gap between the host board and

the module. The combination of soldering flux residuals and encapsulated water could lead to short circuits between

neighboring pads. Water could also damage any stickers or labels.

• Cleaning with alcohol or a similar organic solvent will likely flood soldering flux residuals into the two housings, which is

not accessible for post-washing inspection. The solvent could also damage any stickers or labels.

• Ultrasonic cleaning could damage the module permanently.

The best approach is to consider using a “no clean” soldering paste and eliminate the post soldering cleaning step.