Solder Mask; Requirements On Pcb Layout; Assembly Processes; Huawei Proprietary And Confidential - Huawei ME909 Series Hardware Manual

HUAWEI ME909 Series LTE LGA Module
Hardware Guide

6.7.3 Solder Mask

NSMD is recommended. In addition, the solder mask of the NSMD pad design is
larger than the pad so the reliability of the solder joint can be improved.
The solder mask must be 100 µm–150 µm larger than the pad, that is, the single side
of the solder mask must be 50 µm–75 µm larger than the pad. The specific size
depends on the processing capability of the PCB manufacturer.

6.7.4 Requirements on PCB Layout

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6.8 Assembly Processes

6.8.1 General Description of Assembly Processes

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6.8.2 Stencil Design

It is recommended that the stencil for the LGA module be 0.15 mm in thickness. For
the stencil design. See the following figure:
Issue V0.3 (2013-05-21)
To reduce deformation, a thickness of at least 1.0 mm is recommended.
Other devices must be located more than 3 mm (5 mm recommended) away from
the LGA module. The minimum distance between the LGA module and the PCB
edge is 0.5 mm.
When the PCB layout is double sided, it is recommended that the LGA module be
placed on the second side for assembly; so as to avoid module dropped from
PCB or component (located in module) re-melding defects caused by uneven
weight.
Tray modules are required at SMT lines, because LGA modules are placed on
ESD pallets.
Reflow ovens with at least seven temperature zones are recommended.
Use reflow ovens or rework stations for soldering, because LGA modules have
large solder pads and cannot be soldered manually.

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Mechanical Specifications
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