ADRV9009 assembly notes – BGA preservation and use
BGA preservation and use
BGA component is a highly temperature sensitive component, so the BGA must be stored under constant temperature and dry conditions. The operator should follow the operating process strictly and avoid the components being affected before PCB assembly. Normally the ideal storage environment for BGA is 20 ° C -25 ° C, and the humidity is less than 10% RH (better with nitrogen protection).
Pay attention to the moisture-proof treatment of the BGA before opening the package. At the same time, we should also pay attention to the limit time that the opened component can’t be exposed during the picking & placing as well as the soldering process. This is very necessary to protect the components from being affected and cause soldering problem or a change in the electrical properties of the component itself. Table 1 below shows the moisture sensitive grade classification, which shows the appropriate time that the components must be used for installation and soldering once the sealed moisture barrier package is opened. In general, BGA is a humidity sensitive level 5 or higher. If the components are stored under nitrogen, the time can be relatively extended. Almost every 4-5 hours in dry nitrogen can extend the air exposure time by 1 hour.
Humidity sensitive level
Follow the instruction
Table 1 Humidity sensitivity level.
Constant temperature baking
We often encounter a situation that the components can’t be used out in the corresponding time after the package opened, or the exposure time exceeds the specified time, so we need to bake the BGA components in order to make the component be good solderability before the next use. A constant temperature oven is required: 125 degrees and the relative humidity is ≤ 60% RH.
Humidity sensitive level
The baking temperature should not exceed 125 degrees at most, because too high temperature will change the metallographic structure between the solder ball and the connection of the components, and when these components go to the reflow soldering, the disconnection will have easily happened between the solder ball and the component footprint which will cause PCB SMT assembly quality problems, but we think it was because of the components themselves mistakenly. If the baking temperature is too low, dehumidification will be failed. Baking the components before assembly helps to eliminate the internal moisture of the BGA, and improves the heat resistance of the BGA, reducing the impact that the thermal shock gives the components during the reflow soldering. The BGA components can be used after half an hour from the baking oven when it is naturally cooled.