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+--- Thread: Why does your BGA always fail to be assembled? (/Thread-Why-does-your-BGA-always-fail-to-be-assembled)
Why does your BGA always fail to be assembled? - toyota1515 - 06-30-2022
Here is a possible reason - dimple value:
In manufacturing,
blind vias between L1 and L2
are filled with resin during laminate.
If it's a blind via between L1 and L3,
it's difficult to fill with resin.
Manufacturers would plate and fill it fully with copper.
During production,
due to its aspect ratio,
as well as chemical properties during plating
the surface is always depressed
Its depth is called the dimple value.
This value should be less than 15 um.
Otherwise,
there would be hollows or bubbles,
after the BGA is assembled.
PCBA factories can print a thicker solder paste,
adjust the reflow profile, and extend the heating time,
to drive the bubble out.
While, it's easy to result in other quality issues.
What PCB designers can do:
1. When designing a PCB, ask your manufacturer for a laminated structure;
2. The smaller the aspect ratio, the better. Commonly 1:1 or 0.8:1 (laser drilling),
RE: Why does your BGA always fail to be assembled? - SpbPTSml - 06-30-2022
I would request you to make one post on non FR-4 material like Rogers Material for PCB design esp.
for Low Loss Analog and RF circuit design.
SERDES tracks - differential on Rogers material.
PCIe5 on Rogers Material.
X band wireless transceivers on Rogers Material.
RE: Why does your BGA always fail to be assembled? - toyota1515 - 06-30-2022
Thank you for the advice. I will keep it in mind. My current post is about aluminum boards. Aluminum is a reliable material for LEDs. Unfortunately, not everyone knows this. Rogers material is a fascinating topic to talk about after I finish this.