Manufacturing And Welding - Quectel Smart Wi-Fi Module Series User Manual

8.2.

Manufacturing and Welding

Push the squeegee to apply the solder paste on the surface of stencil, thus making the paste fill the
stencil openings and then penetrate to the PCB. The force on the squeegee should be adjusted properly
so as to produce a clean stencil surface on a single pass. To ensure the module soldering quality,
the thickness of stencil for the module is recommended to be 0.18mm, and the following figure is the
recommended stencil design for LGA pads. For more details, please refer to document [2].
0.55mm
1.5mm
Figure 23: Recommended Stencil Design for LGA Pads
It is suggested that the peak reflow temperature is from 235 to 245° C (for SnAg3.0Cu0.5 alloy). The
absolute maximum reflow temperature is 260° C. To avoid damage to the module caused by repeated
heating, it is suggested that the module should be mounted after reflow soldering for the other side of
PCB has been completed. Recommended reflow soldering thermal profile is shown below.
SC20-W_Manual_R1.0 Confidential / Released 36 / 41