Introduction to the types and repair methods of chip Eco

Classify according to the category of repair content , It can be divided into functions ECO and Timing ECO. function ECO It is to modify the logic function of the chip ,Timing ECO It's repair Setup/hold Time. function ECO It can be changed manually , You can also use tools , such as cadence conformal eco,nandigits Of gof eco.Timing ECO You can use tools directly on the back end （Innovus、ICC/ICC2） Li reform , It can also be used. PrimeTime etc. STA Tools to automatically Fix, You can also manually Fix A small part （ Sometimes Timing dissatisfaction , It could be Transition perhaps cap Too big ）.

Of course, if Timing Difference is too big , From the chip architecture 、 The clock tree structure is further optimized . It may also be that the speed limit of the process has been reached , It's time to change the process .

According to whether the chip has been streamed , Can be divided into PreMask ECO and PostMask ECO.Mask Is the meaning of the mask , Before and after manufacturing the hood .PreMask ECO You can change all the layers made , and PostMask ECO Only the metal layer can be changed , Even a few specified metal layers .

In chip design , There is always some uncertainty , We need to consider reserving a variety of options . such as , Reserve in advance OTP/MTP Come on trim Circuit parameters and logic , Private registers to switch alternate functions and modes , utilize TOP Metal Option、EEPROM、Flash Waiting is also a common and easy-to-use method . as long as BUG It can be repaired or bypassed by software , Or reduce the working clock frequency , Or adjust Process corner, Anyway, the chip that does not affect customers' use is a good chip . It really has little influence BUG, Let the sales reduce the price .