Festkörperelektronik
> Zum Inhalt

Mask production at the fke

The fke operates a HEIDELBERG DWL 66 fs laser lithography system to manufacture 3 inch masks for optical lithography.

Before even thinking of drawing a mask read this rules first!!!

If you are interested in an optical mask, get in contact with Markus Schinnerl.

The mask design

For mask production a drawing in the AutoCAD DXF format for AutoCAD release 12 is required. This file is then translated to a format compatible with our laser writer. You can find the design rules of the conversion program here: P:\PUBLIC\HIMT_DWL66

Obey these guidelines for mask design in order to assure correct translation and also the following additional regulations, resulting partly from other hardware used at the FKE:

1.: Mask size: 3 inches. In principle every mask size up to 6" is possible, but we have no other mask blanks than 3" in store.

2.: The point (0,0) in AutoCAD represents the center of the mask. Center your drawing around this point!

3.: For 3" mask blanks, the structures should be contained in a 4.5 x 4.5 cm square centered around (0,0). Additional text can be put outside of this area. If you use a larger area for your design be aware that you might not be able to use the whole design area since the window of the plate holder of the mask aligners sets the limit to this 4.5 x 4.5 cm size.

4.: Don't use layer 0. Put your whole design in one layer (layer 1 preferred). Delete all other layers used during the drawing process. If you can not delete layers delete the content of all unnecessary layers. If your design is NOT in layer 1 you have to tell!

5.: Use only closed figures such as rectangles and polylines with zero linewidth for your drawing. A single line or a point will prevent the translation program from completing its job. If you work with polylines be sure not to go forth and back on the same line in one move - again, the conversion program will not work at all. A line cannot be shared as part of the boundary of two different figures. Make sure that two adjacent objects are each complete. Do NOT use "special" features like blocks, regions,... even if it saves you a lot of time - the conversion program will NOT work and you will have to do the whole job again the old fashioned way -> rectangles, polylines - nothing else!

If you are not sure how to draw a particular design ask Markus Schinnerl.

6.: Any closed figure in your drawing will be transparent, the area outside your closed figures will be opaque. Keep in mind what you want to do with your mask – if you need it for lift off you will most probably need it inverted. It is also possible to invert a drawing during conversion, so if it makes it easier for you to draw your design you can do it that way. However, if you need a negative image of the pattern be sure to say so!

7.: Islands are opaque areas surrounded by transparent areas. Islands can be formed between two or more closed figures (this is the recommended method ), or with a re-entrant polyline. Only one island per polyline is guaranteed to fracture correctly.

There is also the possibility to apply some XOR logics in the conversion software. For example, if you draw a small rectangle inside a larger one and choose XOR, you will get the "frame" area between the two rectangles exposed and the area inside the small rectangle unexposed. However, keep in mind that this can only be applied for the whole design.

8.: Text is converted to a block font and will be transparent. Only characters and numbers are supported, don't use any special characters.

9.: Lists like the one above are never complete! Before you rush to your AutoCAD-computer and start drawing, contact the operator and let him know what you want. (The questions will be: What are the dimensions? What are the precision requirements? Do you need your mask for a lift off / image reversal process?)

DWL 66 fs Laser lithography system

The DWL 66FS is a high-resolution imaging system where over a million dpi is achieved using a 25-nanometer writeable address grid for exposing metallized plates or wafers.

Design data can be created with any program using DXF (preferred), GDSII, HPGL, Gerber or CIF format and is converted into a LIC format on a “CONVERT“ workstation. Design data transfer to the system is then realized via an FTP connection.

Displacement of the exposures on the plate is achieved with an X and Y positionable stage whose movement is controled by a laser metering system. The Laser writer is supported by a vibration isolation table and is enclosed in an Environmental Chamber to assure that an adequate volume of clean temperature controlled air flows across the instrument during operation.

Minimum exposure size:

Write head 2 mm:  0.6 μm

Write head 4 mm:  1 μm Write head 10 mm:      2.5 μm

feedback

letzte Änderung: 08.03.2010 (ms)