Physics behind metal slotting !!

[kvsidhi]

metal slotting wide metal

Hi ,

I would like to know the physics behind wide metal slotting in ASIC fabrication.
Is anyway this metal slotting helps in getting rid of EM problems.
If so Please let me know how It is ??

Any document is more helpful.

Regards,
-Sidhi

 

[mlxsae]

metal slotting

Metal slots on wide metal areas prevent drifting of the metal whenever it's under stress. We have done some measurements with and without slots and saw really the wire moving. Documents should be found by the FAB.

 

[rfsystem]

Has nothing to do with the degradation of the metal themselve. It avoids delamination of the flowglass from the metal at wide metal areas.

 

[superluminal]

I think this is done to avoid electromigration. you can type "electromigration" in google & you will find some intersting links .

 

[philewar]

I think there are electro-manetic theroy ruling.

Capacitance, inductance, resistance. They will follow maxewell equation or its simple form, i.e. telegraph equation or quasi-static equation.

Best,

philewar

 

[mimosa]

Power supply lines in a chip are designed to be very wide so that EM and resistance effects are minimized. However, there is one problem with very wide metal lines that occurs when the temperature of the chip rised high enough to cause the metal to expand signigicantly.

If the metal expands repeatedly with enough force, the metal
will destroy the isolation and passivation layer that protect the wafer. Impurities and particles will work their way onto the chip, react with the different materials, and cause the chip to fail or work unreliably.

To address this problem, layout designers are required to put slots or holes in the metal at regular intervals.

The origin of this rule is found by the assembly due to high temperature in assembly.

 

[sandusty]

Electro-migrition usually happened in the power ground. However, metal slots are required for all the metal wires (if the size met the requirements). Mimosa gave a profoud/complete answer..

 

[Humungus]

Slots in metals are very important in order to relief stress due to matal dilatation caused by an increase in temperature

 

[maniasonic]

temporature is also one of main considerations.

 

[sunjimmy]

As far as i know, another reason for metal slot is to prevent the stress damage during wafer dicing and packaging.