GenISys (Germany)

Shape positional accuracy is a ubiquitous challenge when writing critical features using electron beam (e-beam) lithography. Positional accuracy can be particularly important when patterning for dense pattern arrays often found in plasmonic device structures. These arrays contain structures critically placed within a few tens or hundreds of nanometers apart from one another, whereby poor positional accuracy on the same order of magnitude would impact overall device performance. The sources of positional accuracy are varied on an e-beam lithography system and can include, but are not limited to beam drift, surface charging, environmental noise, and temperature to name a few. This work demonstrates the impact of shape writing order on sub-100 nm features to tolerate these potential sources of shape positional errors. The shape positional accuracy of both proximity effect corrected (PEC) and non-PEC array patterns are studied using a 20 MHz fixed clock 50 keV Gaussian spot electron beam lithography system exposing at 1 nA with a 60 μm final aperture, and a 20 nm beam step size using 200 nm of ZEP520A from ZEON Chemicals atop a bulk Si substrate. The patterns are transferred via etch or metal deposition. The authors find that both pattern design and data preparation impacts positional accuracy by way of the designed shape order or the reshuffling of shapes, respectively. Resorting the shapes within the arrays allows the beam to continuously raster or meander through the array along the X- or Y-axis, row by row or column-by-column, respectively, while exposing abutting shapes yields optimal shape placement with a negligible impact on writing time.

We present the advantages of the time-and-frequency-domain modeling (TFDM) approach for modeling large-scale photonic integrated circuits embedding many different sub-elements performing diverse photonic functions. Further we discuss scalability issues and show representative application examples.

To overcome several drawbacks of the standard pattern copy procedure used to create the repair shape(s) for a particular defect site, we have developed and implemented a layout based pattern copy method (a.k.a. "database pattern copy"). In general, pattern copy derives the repair structure by comparing a high resolution image of the defective area with the same image of a non-defective area. The repair shape is generated as the difference of these two images, and adjusted for processing purposes. As opposed to the conventional pattern copy method, which derives the reference using information taken from the mask under repair, the new method uses reference information from the <i>original mask design file</i>. As a result, it reduces the CD error of the repair, simplifies the repair process work flow, and greatly reduces the potential of operator error. We present the new method along with experimental results taken from programmed defect repair on our MeRiT MG^TM production tool.

To meet the demand for ever-increasing transmission capacity led by the increase in Internet traffic, up to 10 Tb/s transmission capacity experiments have been demonstrated using wavelength division multiplexing (WDM) and up to three transmission bands. Most of today's commercial WDM systems, however, are capable of 80 channels at 10 Gbit/s in the C-band and similar capacity in the L-band. 40 Gbit/s channel rate WDM systems are not yet widely commercially deployed. To achieve the aforementioned multi-terabit capacity systems for the future high spectral efficiency and the opening of additional transmission wavelength bands will be necessary. Besides the already used conventional C-band and the long-wavelength L-band the short wavelength S-band is the most promising candidate for a third transmission window. A key technology for accessing a new transmission band is the availability of optical amplifiers, which is fulfilled for the S-band by using either gain-shifted thulium doped fiber amplifiers or new erbium doped fiber amplifiers. In this paper we will provide an overview of amplifier types and their possible usage to upgrade to multi-band transmission as well as we will discuss general design options for upgrading transmission bands. In particular, we will show numerical results for Raman based C- and L-band amplification with multiple Raman pumps and different pumping schemes and an experiment for opening up the S-band by a fiber amplifier approach.