Wafer testing and sorting

The wafer is tested twice to determine yield—once after the deposition of the first metal (referred to as in-line parameteric testing) and again after the completion of the last fabrication process (referred to as wafer sort). The first test is also referred to as the wafer electrical test (WET) and is performed in line. In the last test, each die on the wafer is tested for electrical functionality, and the obtained data is used to compute the die yield. 

Advanced Resist Processing and Resist Resolution Limit Issues 

In nature s infinite book of secrecy A little can I read 

In addition, aspect ratio considerations, dependent on mechanical stability and pattern collapse propensity of resist lines, limit the thickness of resists designed for these technology nodes to ultrathin resist thickness regimes ( 100 nm and lower). However, the aspect ratio considerations must be balanced against the etch stability requirements that ensure successful pattern transfer to underlying substrates in a device. Both the aspect ratio and etch stability requirements must be balanced against the intrinsic resolution, particularly pitch resolution, of the resist in question. Hence, there is a trade-off between aspect ratio requirements and etch stability requirements on the one hand, and pitch resolution on the other. Therein lies the motivation for these advanced resist-processing schemes. 

Another type of balance that is struck in resist design for these advanced technology nodes concerns the trade-off between resolution, line edge roughness, and sensitivity. Empirical evidence shows that it is extremely difficult to 

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