TMS320F28335: About BGA SMD way.

Jimmy WANG said:

Does the original factory recommend storage methods and environments after the vacuum packaging of this material is unpacked?

Sorry I don’t understand your question. Are you asking about storage methods and environments after the devices are taken out of the vacuum packaging? Typically, devices are removed from vacuum packaging only right before production. They are not removed from the vacuum packaging and then stored.

Jimmy WANG said:

Is there any suggested process and specification for this material before the SMD manufacturing process?

Please consult www.ti.com/lit/SPRABY1. 

Hi Hareesh,

Yes. I know. but customers do not use all IC on this production.

So they want to know recommended storage methods and environments after the vacuum packaging of this material is unpacked.

Because they encountered some problems. When using the unused BGA last time and producing it, they found that the solder balls were peeling off.

Jimmy,

     I have reached out to a Quality/packaging expert. Today is a holiday in the US. Please wait for a day or two. 

In the interim, please refer to https://www.ti.com/support-packaging/packaging.html and see if your questions are answered there. Specifically, check www.ti.com/lit/SNOA550.

Hi Hareesh,

Thanks for your info. I am looking forward to getting the expert's suggestion.

The customer has some questions as below.

They use 2 different conditions and get the different failed rate.

Currently, there are mainly two batches. Under the same Date Code, the MCU went through different processing procedures at the SMT factory, resulting in defective rates of 43% and 4% respectively. According to the information provided by the SMT factory, the main difference is:

1. After the sealed package is opened, the baking and drying time is 8hr and 24hr. 8hr is the original internal setting value of the SMT manufacturer, and 24hr is the time that was later adjusted by itself.
2. After Batch #2302 was baked and dried, it was placed for 4 days (the manufacturer claimed that it was placed in a drying oven) before being shipped, but Batch #2305 was placed for only 1 day.
3. The temperature rise conditions in the Reflow Profile are different, and the speed of the conveyor belt is also different.
4. Analysis of these two batches of defective slices showed that solder ball peeling occurred in the same area.

So I have a few questions to confirm:
1. Generally speaking, during the SMT process, what are the possible causes of solder ball peeling off of BGA packaged wafers?
2. According to the shelf life (+5) instruction on the label, is this MBB considered to have a shelf life of 5 years?
3. According to the MSL of this TMS320F28335ZJZA, it is Level 3-260C-168HR. Does the Floor Lifetime of 168HR mean that it can be placed directly in an environment of ≦30℃/60% RH after unpacking? Can the product quality be guaranteed?
4. Same as above, or should we use the humidity card indication when unpacking (the humidity card shows 5% is Pink, 10% is not Blue) to judge whether to proceed with the baking and drying process?
5. If baking is required, how long does it take to bake the tray at 125°C (the total thickness of the Chip is 2.05mm, excluding solder balls is 1.49mm) in accordance with the specifications of IPC/JEDEC J-STD-033 baking drying program?
6. If the tray is taken out of the MBB baked for 8 hours, and then placed in the drying oven for 4 days before loading, is there any risk of defects?
7. According to the information provided by the SMT manufacturer, are the temperature rise rate of the Reflow Profile and the speed of the conveyor belt within TI's specifications?
8. Same as above, if the speed is too fast, will it affect the BGA packaged chip?

Jimmy,

     I have reached out to the Packaging team. Likely you will hear back in a day or two. Thank you for your patience.