BGA routing presentation

[John Foster]

Hi Tom.

I was looking at your BGA routing slides and I had a question
about the vias.

For instance what do you mean by via55-25-75. All of the vias seem to have these 3 numbers hanging on them.

Anyway if you could respond it would be much appreciated.
Thanks
John Foster

[Tom]

John,

The three numbers represent the full padstack

The VIA55-25-75

The first number is the Pad Size = 0.55mm (22mil)

The second number is the Finished Hole Size = 0.25mm (10mil)

The third number is the Anti-pad Plane Clearance = 0.75mm (30mil)

This is not the official name of the Via, just the description. We still name our Via's STANDARDVIA and MICROVIA or TESTVIA or BGA80VIA (for a 0.80mm pitch BGA only).

[John Foster]

Tom thanks. I think it is really great of you to help
people out all the anytime.

Thanks again
John Foster