Specific Process Knowledge/Pattern Design

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Unless anything else is stated, everything on this page, text and pictures are made by DTU Nanolab.

Pattern Design and Mask Fabrication

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Pattern Design

For making a pattern on a substrate it is necessary to use a software tool to design the pattern layout. This counts for all kind of lithography and laser cutting. There are a number of different software tools that can be used, some of the more commonly used are:

• CleWin
• KLayout (free)
• L-Edit
• Autocad

At Nanolab we offer all users free access to CleWin 6 (was previous CleWin 5) for their mask layout.

Install CleWin 5 software on your local computer: Click here for guidelines.

Layout file format

• For E-beam lithography you need to prepare a set of files (GDS, V30, sdf, jdf and mgn files). For details about how to prepare the files for E-beam lithography, please see File preparation. For details about how to make aligned E-beam patterns, please have at look at Design of global marks and chip marks

• For laser cutting the layout file has to be saved as a DXF file that is uploaded to the equipment computer.

• For UV-lithography you create a layout file with your design. The file format should preferably be CIF or GDS. The electronic mask layout can be used directly in one of our Mask Less Aligners (MLAs) or you can have a physical mask produced based on the layout file. For more details see below Mask Fabrication for UV-lithography.

• For DUV-lithography and DUV-lithography it is necessary to have physical masks (reticles) produced based on the layout file. The file format has to be GDS. For more details concerning the design of reticles see Design of Reticles.

Mask Design for UV-lithography

Tips and tricks for mask designing

Here you can find

• "Beginners guide to mask design". This is a guide how to design a set of mask.
• Guide to mask making.pdf. Unfortunately this is quite old guide to mask design, but may be useful anyway. Note some links/e-mails etc. are not correct anymore and the mask specifications (CU/CD, DF/BF, RR/WR) are no longer valid.
• Mask polarity and orientation.pdf. This is an short guide how to specify the polarity and orientation of the mask when ordering as well as when used on our maskless aligners. Be aware that the specification of polarity and orientation when ordering at Compugraphics is not the same as when ordering at Delta Mask as we used to do.

Alignment marks

The following alignment marks are suggested to use on the Mask aligners for good pattern recognition. Pleased be adviced that they can be removed in KOH etching.

• Mask aligner:
  • Alignment marks 1 .cif (Right click and Use "save link as...") - You need the program "Clewin" to open this file
  • Alignment marks 1 .tdb - You need the program "L-Edit" to open this file
• Maskless aligner:
  • Simple alignment marks (.gds)
  • Alignment marks with structures to assist in locating the marks during alignment (.gds)
  • Alignment mark for multiple layers, Layer 1 for etch in KOH (.gds)

Alignment marks location

For the KS Aligner, MA6-2 and Aligner-6inch

• The mask's alignment marks for 4inch process:
  • For Back Side Alignment (BSA) alignment marks must be located between -1,0 and +1,0 mm in vertical location from mask center (y=0-+1mm) and exactly at 45mm in left and right in horizontal location (x=+-45mm).
  • For Top Side Alignment (TSA) alignment marks must be located 35-45 mm in left and right in horizontal location and between -2 and +2 mm in vertical location.

• The mask's alignment marks for 6inch process:
  • Both BSA and TSA must be located between -2,5 and +2,5 mm in vertical location from mask center and 60 mm in left and right in horizontal location.
  • Please notice that if you plan to use the automatic alignment option the alignment marks must be displaced from y=0 to y=+/- 1,6mm.

Alignment marks for E-beam lithography

If your UV mask is used to define wafers marks in e-beam lithography with JEOL JBX-9500, you should design your alignment marks in a way the JEOL JBX-9500 recognizes. Please follow the guide here.

Helpful information for chip layout

• Gamma coater & developer chucks + hotplate pins.gds Design file showing the size of the chucks and the position of the hotplate pins in the Gamma tools.

Mask Ordering and Fabrication

How to order a mask

Our standard mask supplier is Compugraphics. They can provide 5" and 7" masks on soda lime glass or quartz. Minimum feature size can be 0.8µm, 1µm or 1.5µm which is reflected in the price. Read a short guide on how to order photomasks from Compugraphics here. Templates for the mask specifications for 5" and 7" masks respectively can be seen here.

The masks have to be ordered in Procure. Nanolab cannot order the mask for you but we do offer a final check of the design and mask specifications before you place the order. You can find a guide on how to order and attach design files in procure here.

If you are using L-edit to design your mask you should remember to mark the top cell as the fabrication cell; a small pink f should show to the left of the cell name in the Design Navigator.

Remember to make only the layers for fabrication visible. The remaining should be invisible. Give each layer appropriate GDS number respectively CIF names before exporting the file. This is done by double click on the layers and fill out the window that pops up.

We can also provide guidance regarding the mask design phase. Please contact the mask team for help and review, E-mail address can be found in Nanolab contact information.

• How to order and attach design files in DTU Fusion
• Templates for 5" and 7" mask specifications

Mask sets made by Nanolab

Nanolab quality control masks

This section contains a description of some of the quality control designs.

ASE standardisation designs: The quality control procedure on the ASE is using the daqmask 2 mask

• File:Daqmask2.pdf
• File:Daqmask2-a.tdb

RIE standardisation design: The quality control procedures on RIE2 is using the dASEfeRIE mask

• File:Daseferie.pdf
• File:DASEfeRIE.tdb

Masks for process development

• Travka mask set (7 masks)