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In the case of BGA and CSP, the solder joint is located on the bottom of the package, so the solder is melted by heating up the entire package while it is covered, using specialized equipment, jigs and tools.
The temperature conditions at this time should minimize temperature variations within the package, and non-melted solder joints must be avoided.
Figure 1-3-3 shows an example of attachment of a sensor during temperature measurement.
Figure 1-3-3. Example of Sensor Attachment during Temperature Measurement
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Figure 1-3-4 shows an example of the BGA having been removed and the solder remaining in pinholder shapes. If the temperature is low, pad peeling may occur, so caution is required.
If the printed wiring board is large, it is important to avoid bending of the printed material due to selective heating, so a bending prevention tool must be placed on the bottom of the printed wiring board, and a bottom heater installed to allow heating of the entire printed wiring board in order to raise work efficiency.
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Figure 1-3-4. Trace After BGA Removal
(Printed Wiring Board Side)
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