what is the meaning of bias in process ?

[pianomania]

some process tape out document note the bias of process. it seems that it is the difference between draw and mask , is it right ?
But why some process have no bias value?

Does it represent the drawing size means the real mask value ?

 

[Fahmy]

I guess that the word "bias" refer to whether the mask is a positive ot negative (inverted) mask, which depends on how the mask is used in the fabrication process.

 

[forkschgrad]

some process tape out document note the bias of process. it seems that it is the difference between draw and mask , is it right ?
But why some process have no bias value?

Does it represent the drawing size means the real mask value ?

yeah, it's the difference between drawn and mask. i belive all experience process bias that's why we use device matching.

 

[pianomania]

some process tape out document note the bias of process. it seems that it is the difference between draw and mask , is it right ?
But why some process have no bias value?

Does it represent the drawing size means the real mask value ?

yeah, it's the difference between drawn and mask. i belive all experience process bias that's why we use device matching.

what i actually mean is why the process document give us the exact size after bias instead of the larger size to let us draw the enlarged size ?

it seems that we will confuse the minumum size to mis-understand the performance evaluation.

 

[forkschgrad]

some process tape out document note the bias of process. it seems that it is the difference between draw and mask , is it right ?
But why some process have no bias value?

Does it represent the drawing size means the real mask value ?

yeah, it's the difference between drawn and mask. i belive all experience process bias that's why we use device matching.

what i actually mean is why the process document give us the exact size after bias instead of the larger size to let us draw the enlarged size ?

it seems that we will confuse the minumum size to mis-understand the performance evaluation.

hmmm.. i'm a little bit confused with your question. there are processes which are subjected to shrinkage when fabricated but they are still drawn using the larger one.

 

[shaq]

Process variation causes bias

 

[pbs681]

Process variation causes bias

so why don't we just draw the dimension after bias

 

[forkschgrad]

Process variation causes bias

so why don't we just draw the dimension after bias

since it's called variation, the result is not consant. what we can do is to minimize it. if we followed the after bias, it might affect the chip size.

 

[pbs681]

Process variation causes bias

so why don't we just draw the dimension after bias

since it's called variation, the result is not consant. what we can do is to minimize it. if we followed the after bias, it might affect the chip size.

can I say that the bias is applied for mask dimension so that the printed pattern will be the one that we drawn.... meaning to say, the bias is for mask variation.....