For further reference, please check out these links, which open up in new windows:

1. LinkCAD Drawing Design Rules

2. ASM 3500 Drawing Design Rules for DXF to GDSII

3. Design Rules for Drawing Masks using AutoCAD - PDFCast.org

We accept AutoCAD® DWG and DXF files up to version 2010.

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. Since DXF files can be rather large, please zip them up before sending them to us. This typically reduces their size by up to  90%.

Use layer 0 only for the insertion of BLOCKs.  Do not draw any entities on layer DEFPOINTS.  Draw all entities on any other layer (except layer 0). Do not turn off layer 0.

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, duplicate, and/or coincident entities.

Remove all HATCH entities. These are ignored by our data format translators. If you find them necessary to include for illustration purposes, then be sure that the original entities that were used to create the HATCH patterns remain in your drawing.

Purge all unused BLOCKs, LAYERs, and other items from your drawing before sending then to us.

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 POLYLINES, POLYLINES of varying width, and POLYLINES that double back on themselves or cross themselves can be processed, so long as you make us aware of their presence.  They require special settings to be used during conversion. In addition, they often require extra labor during the data conversion process. Such labor is charged at the consulting rate as posted on our prices page.

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, defined with a center point and a radius or diameter.

Use BLOCKs (and/or nested BLOCKs) whenever possible in order to conserve file size. All BLOCKS should have a scale factor of 1 in both the X and the Y directions. Mirrored BLOCKs have a scale factor of -1 in one or both directions, and cannot be processed through our data converters. Rotated BLOCKs are usually OK.

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:

If you have features that are completely surrounded by other features on the same layer, the plotter will typically overwrite the inner features - unless something is done to prevent this. This process is called Polygon De-Embedding (described here).  As part of our standard procedures, we will typically run our own de-embedding routines on your data, which also help to identify duplicate entities.

Please specify the data units with your order.  We recommend using at least 5 or 6 decimal places if working in inches, and 4 to 6 decimal places if working in millimeters. Of course, 6 decimal places in mm is 25.4 times more accurate than 6 decimal places in inches.  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. We usually send data the to plotter with 6 decimal places in mm.

Data Extents: Please keep all data within +/- 55 inches (+/- 1400 mm) of the X/Y origin.

Layer names should not exceed 15 characters, and shall have no spaces or special characters other then underscores or dashes.

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.

LINE thickness is ignored. POLYLINE Width is typically maintained.

The following entities are ignored by our converters: SHAPE, POINTS, 3DPOLY, ATTDEF, 3DFACE, HATCH, MLINE, RAY, RTEXT, TOLERANCE, WIPEOUT, POLYFACE MESH and XLINE.

We recommend the use of 274-X data format, which includes embedded apertures.

For advanced designers only: Subfigures (Step and Repeat data) can be employed with just about any size and shape, as compared to custom apertures must fit within 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 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 we must convert DPF data to 274-X data prior to plotting, depending upon the type of plotter used.

We highly recommend that the designer preview their own Gerber data in a Gerber Viewer such as ViewMate, in order to make sure that the data looks exactly like what it is intended to look like - before it is sent to us. This is especially true if the Gerber data file was created not by a Gerber editor to begin with, but by a data conversion program such as LinkCAD or ASM500.  There are several free software packages available on the market that can be used just for this purpose. We highly recommend the free Pentalogix ViewMate product for this purpose.

For further reference, please check out these links, which open up in new windows:

1. LinkCAD Drawing Design Rules

2. ASM 3500 Drawing Design Rules for DXF to GDSII

3. Design Rules for Drawing Masks using AutoCAD - PDFCast.org

We can process polygons/boundaries without a limit to the number of vertices on each. The old 200 vertex limit is now obsolete.

We can process a nearly unlimited number of cell placements and nested cells in each data file.

Circles, arcs and other curves created from AutoCAD design files 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 features that are completely surrounded by other features on the same layer, the plotter or laser writer will typically overwrite the inner features - unless something is done to prevent this. This process is called Polygon De-Embedding (described here).

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 click here for a graphical description of the terms we use on our online order forms..

"Field" refers to everything but the entities (or digitized data).

Digitized Dark (Clear Field) = opaque entities (pads, boundaries, etc.).
Digitized Clear (Dark Field) = clear entities (pads, boundaries, etc.).

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.)
 

Photomask Inspection Criteria

Photomask Defect & Repair Criteria