What are metal and via blockage layers

[vidyacharan]

Hi,

What are metal and via blockage layers and how are they different from normal metal layers?
what are system metal blockages?

 

[ckshivaram]

Hi,
Blockage layer are used when you dont want to use a particular layer in specified area..
Advantage:
You can avoid shorts and avoid the extra parasitics..
Example: If somewhere clock is routed and you dont want it to couple with higher or lower metal then you use blockage layer ...

**broken link removed**
**broken link removed**

 

[vidyacharan]

hi,

can u give me the difference between route guides and routing blockage w.r.t how they fix DRC violations?



Thank you.

 

[rca]

metal or via routing blockage are not a layer, it is just to indicate to the tool, the layers are not available for routing, and should take account for the placement as well.
route guide, is constraints to route some types of signals, like clock nets need double space free around to reduce si (for example), or some specific signal that need wide net ...

 

[vidyacharan]

will route guides be checked for DRC violations?

 

[rca]

route guide will be flag by place & route tool, not by a signoff tool, because the signoff checks the techno DRC , and the place&route checks the techno DRC and the other guide.
I expect some guide could be soft or hard, I mean, soft: as possible respect the rule, hard, reported as a DRC violation if unrespected.