Mask Submission Appendix - Login | Nanolab, UCLA

Mask Submission Appendix (Latest Revision 4/1/08 by Ivan Alvarado)
It is mandatory to read the mask submission appendix before submitting a mask to
the NRF. Read the parts that are related to your own design.
Pattern Extents
To determine the pattern extents of your mask, picture the entire pattern that will be on the plate (see figure
below). It should be possible to draw a rectangle that completely encloses the pattern. The X,Y dimensions
of such rectangle are the Pattern Extents X,Y of the mask. Calculate these in MICRONS and input them in
the corresponding entries of the submission form. This calculation is essential to better estimate the total
cost of the mask. The pattern extents should allow at least a 5mm gap from the edge of the plate in any
direction, for example, the maximum pattern extents for a 5inch plate is 117 mm in both X and Y direction;
for a 4inch plate is 91mm. Both cases assume Automatic Centering. If you pattern does not require
automatic centering, verify that the maximum X,Y coordinate of it does allow for a 5mm gap from the plate
edge.
Automatic Centering
For this entry, the default is YES. Automatic centering is an option whereby the placement of the pattern
with respect to the center of the plate is defined. In the CAD program itself, there are two centers: the
origin (0,0) defined by the coordinate system of the CAD and the center of the pattern itself; in many cases,
these two centers coincide, but it all depends on how the pattern is coded on the CAD. This is illustrated in
the picture below.
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By choosing Automatic Centering YES, the pattern center will coincide with the center of the plate. For
Automatic Centering NO, the origin defined in the CAD will coincide with the center of the plate. See
picture below. The default is YES as we found that this is what it is more common.
Mask Polarity
Mask Polarity Noninverted, the digitized areas are openings. The figure below shows the effect of each
selection. There is no default for this entry and so the user must specify what polarity is desired. Notice that
in the Inverted case, a frame enclosing your entire pattern must be defined (See the Inverted Requirement
section below for more details). DO NOT use the terms Clear Field, Dark Field, Bright Field, Light Field
etc. when referring to mask polarity (see explanation below).
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Clear Field or Dark Field (?)
The terms Clear Field, Dark Field, Bright Field, Light Field, etc. are ambiguous when they are used to
determine the Polarity of the Mask. Those terms are frequently used to describe the general “appearance”
of the mask when it is visually inspected against a light source; some mask shops use those terms to
determine which resist tone is to be used on their plates (which is NOT the case of our mask shop).
However, a Clear Field Mask is not necessarily Inverted and, by the same token, a Dark Field Mask is not
necessarily Noninverted.
Please use the terms Inverted or Noninverted for Mask Polarity whenever submitting a mask order or
consulting about mask making with the NRF Maskshop staff. The section above properly explains how to
determine whether your mask will be Inverted or Noninverted.
Exporting CIF From L-Edit:
1. Open your_layout_file.tdb.
2. Open the master cell.
3. Create a new file, save it as mask_name.tdb.
4. Hit I key to instance your master cell (select your_layout_file.tdb on the “file” pull down menu).
5. Go to File →Export Mask Data, and save mask file as your_last_name_mask_name.cif.
6. Accept the message that no fabrication cell has been designated.
7. Save the exported cif file onto a jump drive or CD.
Un-flattened Files in CIF format (CIF Files with more than one cell)
Some mask files are rejected because the CIF file is not flat or “un-flattened”. What this means is that when
running the CIF file through the conversion software, we detect that there are more than one cell present in
the file. This is mostly due to the fact that users code their masks using cell hierarchies; this hierarchy is
reflected in the number of different cells on the file and how they are recalled in the mask file. Since it is
impossible for us to determine which one is the lead cell in the hierarchy, we require all the CIF files to be
flattened, i.e. the cell hierarchy must be completely removed so that the file is “flat”. If your file is returned
because it is not flattened, follow this procedure (there are many ways to flatten the file; the procedure
below is a long but very sure way to do it using L-Edit):
1. Import CIF File on L-Edit.
2. Open the cell that you want to be on the mask.
3. Select the entire pattern and hit the UNGROUP button until there is nothing else to ungroup. This
effectively removes the cell hierarchy.
4. With the whole pattern still selected, hit the GROUP button and create a new cell.
5. Open the cell you just created.
6. Select Menu/Save Cell to File...
7. Rename Cell File. A new L-Edit file containing ONLY this cell will be created.
8. Close L-Edit. Do not save this file unless you want the cell you just ungrouped to be remain like
that.
9. Open the L-Edit file under which you saved the Cell File
10. On L-Edit Select Cell/Fabricate
11. Select the cell. There should be only ONE cell in the menu. If there is more than one cell, STOP
and redo this procedure again; you made a mistake somewhere.
12. Export Cell into CIF
13. Submit the new CIF file to the Nanolab
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If you are NOT using L-Edit and you are submitting your file in CIF, please follow a similar procedure in
your own CAD. The end CIF file must contain only ONE cell, otherwise the file will be rejected. If you
have questions about L-Edit or the CAD program that you are using, please consult the manual of that
program or the vendor.
Inverted (Clear Field) Mask Layout Requirements:
1. All clear-field masks require a 10 micron wide border surrounding the desired layout.
2. There should be at least a 25 micron gap between the nearest structure and the edge of the border.
3. All area outside of the designated border will remain dark/chrome.
Potential Issues When Using Wires in Mask Layouts:
1. Wires will have rounded-over ends when converted to .lic file format.
2. Shorting may result if wires are not overlapped in original drawing format.
Pointers on Autocad DXF files
1. Save DXF files as either Autocad Rev 12 or 14 versions. Do not save in Autocad 2000 or higher
versions.
2. Avoid using layer 0 on Autocad.
3. Specify the design units (mm, in, cm, etc) in which the DXF file was coded.
4. The Line command is not supported. Use box or polyline instead (See example below):
Autocad Lines
(Wrong Way)
Incorrect
Original Wire
Connected Wires
Correct
Converted Wire
Shorted Wires
Autocad Box or Closed Polyline
(Right Way)
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In the figure above it is desired to have a bridge connecting the two pads. Lines used to define this
bridge will be ignored by the DWL converter. Use a full box or a closed polyline to define the
bridge.
5. The DWL converter does not support HATCH. When a polygon is closed, the converter assumes
that it is filled on the inside and, thus, it is not necessary to hatch it. If this filling is not desired,
specify that the layout is inverted on the submission form.
6. If the HATCH operation is needed for a polygon boolean operation (such as subtraction or XOR)
in order to create an opening or window inside a filled polygon, look for alternatives in Autocad
itself which will produce the same effect without having to instance the HATCH operation. See
example below:
This is an alternative to the HATCH operation in Autocad: It is desired to have an array of chrome
rectangles with a circular window in between. This is typically done in Autocad by drawing a
rectangle and a circle first and then by applying the HATCH operation which will exclude the
circle inside the rectangle. Once that’s done, the mask will be then ordered as “inverted”.
Digitized
Area
Clear
Since the HATCH operation is not supported by the converter software, what can be done is to
draw a circle and then frame it using rectangles around it. Then specify the mask as “noninverted”
when submitting the form.
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Digitized
Areas
7. Some Autocad files which already contain the HATCH operation can still be repaired by the
nanolab staff. Please consult directly to the nanolab staff. Be aware that there are cases in which
there is no practical way to repair the file so that the mask will have to be remade on Autocad in a
way that the HATCH operation is avoided.
8. When using multiple layers on Autocad, the label names must not contain any special characters
or spaces.
Submitting Mask Layouts to UCLA NRF:
1. Complete a NRF Mask Fabrication Submission Form for each mask layer. Make sure that you
have the latest version of the submission form.
2. Mask filenames may not contain spaces or any other special characters. Underscore bar and dashes
are OK.
3. Bring the submission form(s) and cif file(s) to the Nanolab office. You can also email the files to
maskshop@seas.ucla.edu, Ivan Alvarado (ialva@ee.ucla.edu), or Joe Zendejas
(zendejas@ee.ucla.edu)
Requesting a Quote for a Mask
In the lower right side of the submission form, an estimated cost of the mask will be displayed.
This estimation depends on the Pattern Extents X,Y declared on the submission form. If properly done by
the user, this cost estimate is fairly accurate (see Pattern Extents section above). This is NOT a quote in the
strict sense, it is a cost estimate. Be aware that the Nanolab is not responsible for an improper calculation of
the pattern extents and will send an invoice according to the real Pattern Extents shown in the mask after
exposure.
Mask Charges
Clear
• Nanolab Users (either UCLA or NonUCLA): If you have a UCLA Nanolab badge, write your
badge number on the corresponding submission form entry (Badge # / Recharge ID / PO #) and
specify that it is a nanolab badge number. Your nanolab account will be automatically charged.
• UCLA customers that are NOT nanolab users: Provide account number or recharge ID.
• UC System customers that are NOT nanolab users: Provide UC account number and
administrative contact person in charge of that account.
• Other customers (Non-UC system academic or industry that are NOT nanolab users): Provide PO
number and forward it along with mask submission form.
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Mask Pick Up and Inspection
1. The mask can be picked up from the mask pick up table located to the left as you enter the Mask
Writer room. Outside customers will get their mask shipped by the carrier of their choice at an
extra charge. Provide account number for carrier, if available.
2. It is the user’s responsibility to inspect the mask for errors immediately after receiving it. If there
is any error on our side, we will remake the mask at no extra charge. This policy is void if the
mask has already been used on the aligner or more than five days have passed after mask pickup.
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