Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

layout connection using different metalization layers

Status
Not open for further replies.
J

Junus2012

Advanced Member level 5
Joined
Jan 9, 2012
Messages
1,552
Helped
47
Reputation
98
Reaction score
53
Trophy points
1,328
Location
Italy
Activity points
15,235
Dear friends,

I am using the CMOS technology from AMS. it supporting me with four metal layers. except metal 4, I have metal1 and metal 2 and metal 3 having the same via and contact Dimensions. my question is there any different physical properties between them ? I see people are avoiding using higher metalization layers but I don't know why . I only thinking that because metal 3 for example have a deeper via then it has higher contact resistance but I am not sure nor I don't know if might make a difference


Thank you very mmuch
 

isn't the top metal meant for power routing? that is pretty common.
 
Dear Sam :D

in my technology, the top metal layer Metal 4 has big via and contact width, therefore in my circuit I used metal 1 for the VDD and GND as any other connection, this is again a question, why should the power rails be the top layer ?
 

you are confusing power rails with power routing (stripes, rings, trunks, etc.)
 

Ok let me clear it again,

you mean to say for the rails only one should use the top metal layer, but the routing is can be done as for other kind of signal connection,
 

For routing power to the cells, it has to be done in M1 (the lowest metal). These are called rails. For distributing the power across the chip you will use rings and stripes, typically in the highest metal. In your case, that is M4.
 

Check your layout design rules. Is your metal 4 considered "top metal" by your design rules?
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top