Flip chip design layout Issue

[neoflash]

flip chip design

Flip-chip package era comes, our floorplan of chip layout looks full of bumps. Can we put active circuits under the bump?

Added after 19 seconds:

Or we just waste those chip area? Any reference doc welcomed, thanks!

 

[leeenghan]

Hi,

I thought it is always possible to put circuit under the bumps? The more complicated flip-chip has the pad driver inside the core also. In this case, it is obvious that the area is taken up by the pad and not core logic or macro can be placed there.

Regards,
Eng Han
www.eda-utilities.com

 

[bg21359]

That may depends on what kind of circuitry you have. Usually you want to put circuitry sensitive to alpha particles far away from bumps, such as memory cells and flip-flop to reduce your soft-error rates.

 

[neoflash]

That may depends on what kind of circuitry you have. Usually you want to put circuitry sensitive to alpha particles far away from bumps, such as memory cells and flip-flop to reduce your soft-error rates.

thanks for pointing out alpha particle effect, how about stress effect due to bump solder?

 

[bg21359]

stress effect due to bump: No clue... I don't think this can affect your transistor since bump is far away from your transistor. The stress may affect how you choose your top level interconnect and dielectric materials.[/quote]

 

[neoflash]

if I put analog circuit under the bump, the stress on silicon might incur modeling of their behavior incorrect, is it a problem for flip-chip?

 

[Son]

It depends on your process. A special top metal layer is needed.

 

[YESH_23]

plz help me in knowing about flip chip & what is ment by bumps..?

Thanx in advance

 

[neoflash]

plz help me in knowing about flip chip & what is ment by bumps..?

Thanx in advance

flip chip is a kind of novel package having good performence in high speed.
Bump is the metal link between chip and package substrate.

 

[Son]

plz help me in knowing about flip chip & what is ment by bumps..?

Thanx in advance

This image shows the difference between wire bond and solder bump packagings. In the later case one says it's a flip chip: the chip is up side down.
**broken link removed**