Should we avoid dummy structures?

[eda4you]

Dummy structure

Hi!

Last day I had a discussion with a (experienced) analog designer (I's really a good one and I esteem him.) He said that he dislike dummy structure because his experience shows him that sbd profits even more by increasing the device area than on using dummies.

So, what are your comments!

 

[muldersun]

Dummy structure

If not important, I think it doesnot need

 

[eda4you]

Re: Dummy structure

If not important, I think it doesnot need

????? :x

 

[flyankh]

Dummy structure

I agree with muldersun.If the circuit is not important,the dummy doesn't need.

Regards

flyankh

 

[ambreesh]

Re: Dummy structure

From my discussion with some analog layout professionals, it is being observed that the designers are avoiding use of dummy devices. The are mostly used for critical devices and devices sitting on the edge of the layout.
Also the thing depends on how good the fab' process is.

 

[ambreesh]

Re: Dummy structure

I was told that stability of the process determines this a lot.

 

[linxf2003]

Re: Dummy structure

Layout guys will not add dummy themselves. They all depend on designer to tell them. In current process, removing a dummy will not save much areas. Why not?

 

[sunny153]

Re: Dummy structure

i support that we should try to avoid the dummies. But in todays DSM processes, rather than increasing the area, it is beneficial to use dummies.

 

[nile_king]

Re: Dummy structure

I think that dummies important for the importand devices
it's important for resistors for example as its absolute tolerance much less than the relative tolerance

 

[yibinhsieh]

Re: Dummy structure

I think in ADC/DAC reference circuits, the dummy circuit is essential.

For digital circuit, the dummy circuit is not needed.

Yibin.

 

[omsi]

Dummy structure

hi,

i believe there is necessity of placing dummies on either side of the matched devices.
it reduces the variations caused because of etching process.
if the circuit needs the extra devices to be added after manufacturing we can make use of these.

 

[piao]

Dummy structure

I agree with ambreesh.

Every coin has 2 sides, I want to say dummies sometimes bring you big cap and something you do not want, so everytime you should think which one can benefit you more.