Conventionally, the resolution limit of a lithography system with wavelength l and numerical aperture NA is given by half-pitch = 0.25 wavelength/NA. With the use of EUV lithography, however, electron blur needs to be added [1]. The impact of this blur is to reduce the contrast [2]. Blur reduces the modulation amplitude by a factor… Read More
Previously, I had indicated how detrimental stochastic effects at pitches below 50 nm should lead to reconsidering the practical resolution limit for EUV lithography [1]. This is no exaggeration, as stochastic effects have been observed for 24 nm half-pitch several years ago [2,3]. This then leads to the question of whether … Read More
The latest significant development in EUV lithography technology is the arrival of High-NA systems. Theoretically, by increasing the numerical aperture, or NA, from 0.33 to 0.55, the absolute minimum half-pitch is reduced by 40%, from 10 nm to 6 nm. However, for EUV systems, we need to recognize that the EUV light (consisting … Read More
There has been much interest in Huawei’s and SMIC’s plans for 5nm production in the near future. Since there is no use of EUV in China, immersion DUV lithography (with a 76 nm pitch resolution) is expected to be used along with pitch quartering to achieve pitches in the 20-30 nm range expected for the 5nm and 3nm nodes [1].… Read More
Resist blur remains a topic that is relatively unexplored in lithography. Blur has the effect of reducing the difference between the maximum and minimum doses in the local region containing the feature. Blur is particularly important for EUV lithography since EUV lithography is prone to stochastic fluctuations and also driven… Read More
The majority of EUV production is on 5nm and 3nm node, implemented by late 2022. Metal oxide resists have not been brought into volume production yet [1,2], meaning that only organic chemically amplified resists (CARs) have been used instead until now. These resists have a typical absorption coefficient of 5/um [3,4], which means
The discussion of any particular lithographic application often refers to imaging a single pitch, e.g., 30 nm pitch for a 5nm-family track metal scenario. However, it is always necessary to confirm the selected patterning techniques on the actual use case. The 7nm, 5nm, or 3nm 6-track cell has four minimum pitch tracks, flanked… Read More
On a DRAM chip, the patterning of features outside the cell array can be just as challenging as those within the array itself. While the array contains features which are the most densely packed, at least they are regularly arranged. On the other hand, outside the array, the regularity is lost, but the in the most difficult cases, … Read More
The release and scattering of photoelectrons and secondary electrons in EUV resists has often been glossed over in most studies in EUV lithography, despite being a fundamental factor in the image formation. Fortunately, Intel has provided us with a laboriously simulated electron release and scattering model, using the GEANT4… Read More
Electron beam lithography is commercially used to directly write submicron patterns onto advanced node masks. With the advent of EUV masks and nanometer-scale NIL (nanoimprint lithography), multi-beam writers are now being used, compensating the ultralow throughput of a single high-resolution electron beam with the use… Read More
