What is testchip and why we need them ?

[mr_vasanth]

What is Testchip in ASIC/SOC terms ? why and when a company will develop a testchip ?

 

[lohi21]

mr_vasanth,

Test chips are normally be done for the verification of IP's on die, or checking for new technology or even it could be to check the behavior of the IP with the different technology on die.

All aspects of chip design is the same for test chips and production chips.

but can see some relaxation in terms of DRC's and many more before for tapeout.

 

[kirteshmiet]

Hi Vasanth,

As the name it self telling so it is used for testing new technology, chanllenges and also what will be our success on silicon (yield) if we roll out the same technology. and as far as i know when we go to new technology specially lower node then drcs becomes more so bacically we try to focus more on physical verification and timing & area part of it and also agree with lohi21..

cheers
Kirtesh

 

[mr_vasanth]

Thanks lohi and kirtesh ! That gives a good idea.

So, I believe that test chip won't make part of any of the products available in the market (like mobilephone, router, etc.)
may be their life will end just in the lab ?

Generally, How many pieces of a testchip will be fabricated/manufactured in the foundry ?

 

[rca]

To test the technology/ip, you will pass ESD/latchup tests, you could also request some corner lots (SSS, FFF, FSF....), so 50 typicals, and 20 parts for each corners.
And you could test them, in temperture range / voltage range to push at the limit and confirm the stable results over.

 

[mr_vasanth]

Hi rca,

I believe functional testing of the IP involved in the testchip also will be done in addition to the ESD/latchup tests you have mentioned.

I could not understand what are those corners SSS, FFF, FSF. Could you please explain ?

Thanks

 

[rca]

SSS, FFF.. are N P mos transistors variations.