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Xpert Users

Any Institution willing to utilize the HNF has to provide a so-called Xpert User. The task of an Xpert User is the monitoring and coordination of the processes of all users of an institute. He takes part in the weekly HNF meeting.

Xpert Users:

IBG-1N. Braun
IPH (RWTH)J. Richter
PGI-7R. Borowski
PGI-8M.PrömpersM. Banzet
PGI-9 III-V NassbänkeN. Braun
2. Pys. Inst (RWTH)M. Goldsche

Every user is to be allocated to an Xpert User. If an institute is not able to provide an Xpert User it may ask other institutes to take over the task of coordination of their users.

New Süss MA-8 Mask Aligner online

Our optical lithography capabilities are strengthened by a new tool, the SUSS MA8, which will be referred as Mask Aligner 4. The tool is able to handle samples from 1×1cm up to 200mm wafers. At the moment it has a broad wavelength range from 250nm to 405nm, which enables processing of DUV-resists (UV6, UV26) as well as i-line resists (AZ52XX; n-Lof; SU 8). For we have the additional filter, it is in principle possible to narrow this bandwidths.

MA-8 Mask Aligner

In our test we reached resolutions of 500nm and better (depending on the quality of the sample and how many people were standing around...). This exceeds the resolution limit of our conventional optical masks. But for we have developed a Cr-etching process, we will improve the standard mask process by replacing the limiting wet chemical chromium etch by a dry etch. Our test mask, with which we obtained the resolution here, were done in house. The new mask process includes proximity correction so that it is possible to get high quality structures in the µm and in the ~300nm range simultaneously.

One key feature of the tool is the overlay accuracy: Of course it depends strongly on the markers used. You can use our old marker structures in manual alignment mode, which results in an overlay as you know from Mask Aligner 1-3. If your sample is large enough, that you can place your alignment markers in a distance of at least 13mm, then, by choosing the right marker system, you use the Assisted Alignment Mode. The wafer chuck is motorized and the step size is 100nm in x- and y-direction. With the split field optics the camera pictures are evaluated by the tool and via a display it shows you how to improve the achieved alignment. Following the alignment procedure, which includes evaluation of the vernier structures, you end up in overlay better than 0.5µm.

In the picture you see a screen shot in contact after alignment. The vernier structures are designed that one tick correlates to a misalignment of 100nm. All in all from starting up the tool, loading the exposure program, preparing the tool, do the alignment training (teaching the tool the markers you use) and the alignment procedure itself, it took me about 20 minutes to get this result. And, which is also important, is reproducible.

For further information refer to

Jürgen Moers
Tel 2344