Mapper Lithography has introduced its first product, the FLX–1200, which is installed at CEA-Leti in Grenoble (France). This is a mask less lithography system, based on massively parallel electron-beam writing with high-speed optical data transport for switching the electron beams. This FLX platform is initially targeted for 1 wph performance for 28 nm technology nodes, but can also be used for less demanding imaging. The electron source currently integrated is capable of scaling to 10 wph at the same resolution performance, which will be implemented by gradually upgrading the illumination optics. The system has an optical alignment system enabling mix-and-match with optical 193 nm immersion systems using standard NVSM marks. The tool at CEA-Leti is in-line with a Sokudo Duo clean track. Mapper Lithography and CEA-Leti are working in collaboration to develop turnkey solution for specific applications.
At previous conferences we have presented imaging results including 28nm node resolution, cross wafer CDu of 2.5nm 3 and a throughput of half a wafer per hour, overhead times included. At this conference we will present results regarding the overlay performance of the FLX-1200.
In figure 2 an initial result towards measuring the overlay performance of the FLX-1200 is shown. We have exposed a wafer twice without unloading the wafer in between exposures. In the first exposure half of a dense dot array is exposed. In the second exposure the remainder of the dense dot array is exposed. After development the wafer has been inspected using a CD-SEM at 480 locations distributed over an area of 100mm x 100mm. For each SEM image the shift of the pattern written in the first exposure relative to the pattern written in the second exposure is measured. Cross wafer this shift is 7 nm u+3s in X and 5 nm u+3s in Y. The next step is to evaluate the impact of unloading and loading of the wafer in between exposures. At the conference the latest results will be presented.
The MATRIX platform integrates new types of modules for handling and alignment capability and this represents two new and innovative aspects for multi-beam lithography. Results on performances in terms of robustness of the different modules in real manufacturing conditions, including the interface of the MATRIX platform with the SOKUDO DUO track will be reported. A new type of alignment solution was developed by MAPPER. This paper will show the first results on alignment sensor repeatability. Preliminary results on the overlay performance of the MATRIX platform will be presented and discussion will be engaged to position the MAPPER alignment concept with respect to the ITRS roadmap expectations.
MAPPER Lithography is developing a maskless lithography technology based on massively-parallel electron-beam
writing. In order to reduce costs and to minimize the footprint of this tool a new alignment sensor has been developed;
based on technologies used for DVD optical heads. A wafer with an alignment mark is scanned with the sensor, resulting
in an intensity pattern versus position. From this pattern the mark position can be calculated.
Evaluations have been made over the performance of this type of sensor using different mark designs at several
lithography process steps for FEOL and BEOL manufacturing. It has been shown that sub-nanometer reproducibility
(3σ std) of alignment mark readings can be achieved while being robust against various process steps.
C. van den Berg, G. de Boer, S. Boschker, E. Hakkennes, G. Holgate, M. Hoving, R. Jager, J. Koning, V. Kuiper, Yue Ma, I. van Mil, H. W. Mook, T. Ooms, T. van de Peut, S. Postma, M. Sanderse, P. Scheffers, E. Slot, A. Tudorie, A. M. Valkering, N. Venema, N. Vergeer, A. Weirsma, S. Woutersen, M. Wieland, B. Kampherbeek
Currently, three MAPPER multi-electron beam lithography tools are operational. Two are located at customers, TSMC
and LETI, and one is located at MAPPER. The tools at TSMC and LETI are used for process development. These tools
each have 110 parallel electron beams and have demonstrated sub-30 nm half pitch resolution in chemically amplified
resists.
One important step towards the high volume tool is the capability to stitch the exposure of one electron beam to the next.
The pre-alpha tool at MAPPER has been upgraded with an interferometer to enable exposures with a scanning stage and
demonstrate first beam-to-beam stitching. A scan of 200 micrometers has been used to create a stitch area of 50 x 3
microns. The stitch error over all stitches was found to be below 25 nm.
The electron beam position stability during the 10 seconds required for beam-to-beam stitching showed a contribution to
the stitch error of 2.3 nm. The beam separation measurement, used to correct the static error, adds about 2.2 nm and the
stage stability and linearity adds another 5 nm in the scan (interferometer) direction. In the perpendicular direction the
stage instability gives the largest contribution to the stitch error (15 nm) due to the use of capacitive sensors.
Overall, the electron beam stability and the beam position correction method work correctly and with sufficient accuracy
for the high volume tool, 'Matrix'. The wafer stage for the Matrix system will incorporate full interferometer control to
attain the needed positioning accuracy and stability.
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