Hardware Design V1.0

NB-IoT Module Series
BC95 Hardware Design
BC95_Hardware_Design Confidential / Released 41 / 45
7.2. Soldering
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 at the hole of the module pads should be 0.15mm. For more details, please refer to
document [1].
It is suggested that the peak reflow temperature is 235 ~ 245ºC (for SnAg3.0Cu0.5 alloy). The absolute
max reflow temperature is 260ºC. To avoid damage to the module when it is repeatedly heated, it is
suggested that the module should be mounted after the first panel has been reflowed. The following
picture is the actual diagram which we have operated.
Time
50
100
150 200
250 300
50
100
150
200
250
160 ºC
200 ºC
217
0
70s~120s
40s~60s
Between 1~3 ºC/s
Preheat Heating Cooling
ºC
s
Liquids Temperature
Temperature
Figure 27: Ramp-Soak-Spike Reflow Profile
7.3. Packaging
The modules are stored inside a vacuum-sealed bag which is ESD protected. It should not be opened
until the devices are ready to be soldered onto the application.
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