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With the development of our state of the art Internet
Business Center, our goal is becoming a reality, making it remarkably Quick & Easy for
you to order and promptly receive your photoplots and photomasks. At the
Photoplot Store, we continue to scour the world in order to bring you the
highest quality products at very reasonable prices. In order to provide
you with the lowest prices possible, and in order for us to
deliver our products as quickly as possible, we encourage you to provide us with ready to run plot data that requires
an absolute minimum of setup and preparation.
In order for you to perform your design work as efficiently as possible, we recommend a number of excellent software
and hardware products that you can use to create your own plot files. With the Gerber
editors, you get the added benefit of being able to see exactly what your plot
will look like. Create and optimize your designs, then prepare your data
for plotting with your choice of our tested and recommended
tools:
Bay Technology's LinkCAD - Really Cool Software!
Recommended Design and Conversion Procedures for Photoplotting at HiDEC -
University of Arkansas - Good Background Info!
CADopia - FREE Downloads!
Downstream Technology's
CAM350
Fletcher
Automation's OPAL, JADE, RUBY, & JPS
Bay Technology's LinkCAD
ZOTO
Technologies - FREE AutoLISP Routines
Be sure to visit the Cad
Portal,
the Internet resource for engineering professionals.
Here are a few DESIGN RULES that we
suggest: | AutoCAD® | Gerber
| GDS | EPS |
AutoCAD®/IntelliCAD DWG/DXF Data
We accept AutoCAD® DWG and DXF files up to version 2007.
Please construct your designs in Model Space, not Paper Space.
DXF files require less processing on our part, and therefore often go faster
through the system.
Use layer 0 only for the insertion of BLOCKs. Do not draw any entities on
layer DEFPOINTS. Draw all entities on any other layer.
Remove all POINT entities.
Remove all LINE, ARC, and POLYLINE entities that both begin and end at the
same point and have no vertices in between - i.e. have zero length.
Remove all LINE, ARC, and POLYLINE entities that do not form, or
cannot be readily joined to form, a completely closed boundary or polygon, or
which are not otherwise part of the design.
Remove all redundant and/or coincident entities.
Remove all HATCH entities.
Purge all unused BLOCKs, LAYERs, and other items from your
drawing. Remove all data that you do not want to appear
on your photoplot or photomask; or if it useful reference data, please move it
to a layer that is either labeled as "reference", frozen or turned
off. Close all gaps between the endpoints of all the
LINE, ARC, or POLYLINE entities that are intended to form a continuous outline
- making sure that the endpoint of each entity exactly matches the start point
of the next entity. Using the FILLET command set to a zero radius can
help here. Join all LINE and ARC entities that make up a single
continuous boundary into a single closed zero-width POLYLINE outline.
(The PEDIT and BOUNDARY commands are useful for doing this.) CIRCLE,
SOLID/PLANE, and TRACE entities are OK. We process LWPOLYLINE entities in
exactly the same way as we do for POLYLINE entities. Tapered
PLINES are accepted, so long as you make us aware of their presence. They
require special settings to be used during conversion. SPLINE entities
are now accepted. SPLINES are converted into segmented arcs using straight
line segments. The accuracy of the conversion depends upon the radius
tolerance that we use to govern the conversion, which we typically set at 50 nm.
ARC's and curved PLINES are converted to segmented arcs in the same way that
SPLINE entities are processed, as described above. CIRCLE
entities are maintained as is. In other words, they are converted to round
pads. Use BLOCKS (and/or nested BLOCKS) whenever possible in order to conserve file
size.
We do not recommend using "convoluted", or self-intersecting
POLYLINEs. ("Butterfly" targets are often the culprit
here.) Each section of such entities should be separated into its own
closed zero-width POLYLINE outline. Processing TEXT:
-
We can now process MTEXT!
-
True Type fonts may be used in addition to the standard SHX
fonts. -
Be sure to set up the TEXT STYLES before you
begin entering your TEXT or MTEXT entities. Then, make sure that all TEXT
and MTEXT entities use the defined TEXT STYLES. -
Please consider putting all TEXT and MTEXT entities on separate
layers from other entities. These often require separate processing, and
this will help to facilitate smoother and faster operations. -
If the data is in DWG or
DXF format, and if the design contains TEXT entities of more than one font, then
there will be an additional data conversion fee per additional font per file.
Please see our prices page for more details.
All entities, including TEXT and MTEXT, that have extrusion
values other than 1.0 (or that have any extrusion value associated with them)
pose significant problems for our data converters. Extruded (or any other
3-D) entities are not recommended. Be sure to replace all such
extruded data with entities that have no extruded values. All data
must be parallel to the current UCS plane. If you have features that are completely surrounded by other
features on the same layer, and if you want the inner features to have the
opposite tone as the features surrounding them, we consider this to be a design
error - unless it is pointed out to us that we need to do something to prepare the
data in these areas. To help eliminate the occurrence of this type of
problem, we recommend the use of either one of the following two design
techniques: (1) for laser photoplots please separate the areas that are to be dark from areas that are to be clear by putting
them onto different layers, and name the layers so that the order of the
"paint & scratch" operations is unmistakable, or (2) for
photomasks please construct new features that cover only the areas in between
the nested features. Click here to see an illustration of our
recommended construction technique for Nested Boundaries/Polygons.
For data that is on several layers which are intended to be combined into a
composite image or photoplot, please specify the order in which the layers are
to be processed, and whether or not each layer should be clear or dark.
Please specify the data units with your order. We recommend using
at least 4 or 5 decimal places if working in inches, and 3 or 4 decimal places
if working in millimeters. Our photoplotter accepts data having up
to 6 decimal places in inches or in mm. We can process data in just about any units,
so long as you tell us what those units are. Data Extents:
Please keep all data within +/- 55 inches (+/- 1400 mm) of the X/Y origin.
Layer names should not exceed 15 characters. Whenever possible,
please use a 1:1 scale for all inserted blocks. Other scale factors often
have a adverse affect on the conversion of curved features to the segmented arcs
that we use for plotting. REGION entities, and Boolean operations
between them (subtraction, intersection, ...) are allowed, but they require
special processing. Please let us know if you've used REGION entities in
your design. LINE
thickness is ignored. The following entities are ignored by our
converters: SHAPE, POINTS, 3DPOLY, ATTDEF, 3DFACE, HATCH, MLINE, RAY, RTEXT,
TOLERANCE, WIPEOUT, POLYFACE MESH and XLINE.
Gerber Data
We recommend the use of either 274-X, F9000/MDA, or DPF data formats, using
embedded apertures, and subfigures as needed. (274-D files with separate
aperture list files can be processed, but not without the possibility of
introducing some sort of input or conversion error, especially for custom
apertures.) Subfigures (Step and Repeat data) can be just about any size and
shape, whereas custom apertures must fit with about a 1" to 2" inch
square area. Subfigures may be generated from panelized Gerber data,
inserted DWG/DXF BLOCK entities, or from GDSII structures or cell placements.
For 274-X data, there is a limit to the total number of arrayed subfigure
placements at about 512.
For F9000/MDA data, the limit of arrayed subfigure placements is about 50,000.
There is no known limit for arrayed subfigure placements in DPF
data, except that at times we must convert DPF data to either 274-X or F9000
data prior to plotting, depending upon the type of plotter used. We
recommend that the designer preview the Gerber data in their preferred Gerber
Viewer/Editor, in order to make sure that the data looks exactly like what it
is intended to look like before it is sent to us. (There are several free
software packages available on the market that can be used just for this
purpose.)
GDSII Data
We can process polygons/boundaries without a limit to the number of vertices
on each.
We can process a nearly unlimited number of cell placements and nested cells in
each data file. DXF/DWG circles, arcs and other curves will be converted to
segmented entities before creating the photomask or photoplot. Please
specify the tolerance on the radius or entity width that you need for us to
meet. Unless otherwise specified, we will use a 50 nm radius tolerance. Donuts created from DWG/DXF data will not close properly at the
start/end point. Please use a closed zero-width boundary/polyline
instead, as roughly shown here. If
you have boundaries that are completely surrounded by other boundaries on the
same layer, and if you want the inner boundaries to have the opposite tone as
the outer boundaries, this will be considered to be a design error unless it
is pointed out to us that something needs to be done on our part to prepare
the data in these areas. Click here to see an illustration of our
recommended construction technique for Nested Boundaries/Polygons. For data that is on several layers which are intended to be combined into a
composite image or photoplot, please specify the order in which the layers are
to be processed, and whether or not each layer should be clear or dark.
EPS/PostScript
We recommend exporting your design to EPS v3.0.
PostScript is the industry standard for sending documents to
high-resolution printers. LinkCAD's PostScript-compatible export has been
optimized for producing low-cost masks using high-resolution laser printers. The
PostScript export can also be used to generate photoplot and photomask data.
Processing PostScript Data
Our LinkCAD converter relies on two external tools to import PostScript:
pstoedit and
Ghostscript. These tools are distributed under the
GNU General
Public License.
EPS files may contain either vector data or raster data, or
both. Vector data may be processed quite readily, while raster data cannot
be processed with LinkCAD!
We strongly suggest that you download and install the program
called GSView,
which is the graphical interface for Ghostscript. This viewer will enable
you to see exactly what your data will look like as it goes through the
conversion to Gerber format. If the results don't look exactly like what
you've created using Adobe's Illustrator or other such program, then you might want
to make some changes to see what works and what doesn't.
Additionally, we suggest that you install
PSTOEDIT, and then
attempt to convert your data to DXF format before you send it to us. Then,
you can view it with IntelliCAD. If
it's not all there, then you will most likely have to revise your design to
eliminate any non-vector features. LinkCAD yields much better results than
pstoedit does by itself, that's why we use it!
If there is any text in your design, we highly recommend that you explode all the
text into paths/polygons/outlines before exporting the data to an EPS file.
In Adobe Illustrator, the command
sequence is to first select all text, then choose "create outlines -crtl-shft-O"
from the Type menu. Using this method creates outstanding text quality and
appearance on your photomask. If you are using another design tool and do
not have the capability to explode the text, then please embed the font when
you export your data to EPS format. Also, please use one of the system or TrueType
or OpenType fonts (such as Arial, Courier, Times New Roman, etc.), while avoiding any of the
proprietary
fonts (such as Helvetica, Myriad, and Monotype fonts).
Image Resolution of EPS Data:
The database resolution of our LinkCAD data conversion program is always 0.001 microns, or 25,400,000 dpi
(dots per inch). There are, however, several factors that prevent you from
achieving such a high resolution for your PostScript generated masks:
PostScript calculates in 72 dpi units. To convert from nanometers to 1/72
inches, LinkCAD instructs the PostScript processor to multiply the units by
2.83464566929E-6. The calculation is done with very high precision and the
actual limiting factor is the printer's resolution. If the printer has a
resolution of 4800 dpi, the minimum feature size and the maximum error would be
approximately 5.29 microns.
Be careful, however, if you are working with repeated structures (comb
structures) such as alignment masks. Because 1/4800 dpi is not an integer multiple
of 0.001 microns, you get an interference pattern, which offsets your structure
by 5.29 microns at every wavelength, which in this example is roughly 84 mm
long.
We suggest that you set your EPS output resolution to the
highest setting possible in order to maintain the best possible image quality.
Terminology
conventions used by IPC:
Digitized Dark (Clear Field) = opaque entities (pads, boundaries,
etc.).
Digitized Clear (Dark Field) = clear entities (pads, boundaries, etc.).
"Field" refers to everything but the entities (or digitized data). RRCU
(Right Reading Chrome Up) = Not Mirrored by IPC.
RREU (Right Reading
Emulsion Up) = Normal; Not Mirrored by IPC.
RRCD (Right Reading Chrome Down) = Mirrored by IPC.
RRED (Right Reading Emulsion Down) = Reversed; Mirrored by IPC.
(Note: These definitions will apply whether there is text or not, and especially
applies if there is text that reads both ways on the same photomask [and yes,
we've seen this happen].
These will be verified by the customer's examination of check plots prior to
manufacturing.)
Information to help you determine
your Photomask Specifications for...
Inspection Criteria
Defects & Repair
LinkCAD,
from Bay Technology,
Inc. is a robust, powerful, and very easy to use data format translation utility
capable of importing and
exporting GDSII, DXF, CIF, LASI, Gerber RS274-X, and IE3D files. It can import Compass files,
and it can also export EPS Postscript files
to drive the world's most accurate plotters. A viewer may be purchased
that is very useful for visual confirmation of the design and to help identify
problem areas.
Click on these links to register for a FREE, Fully Functional Trial Version of
LinkCAD for Windows,
Linux,
Sun Solaris(TM).
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