Calibre Manufacturing Tools in the NDN (RET, MDP and FRACTURE tools)

Mentor Graphics’ Calibre CAD suite incorporates a number of diverse tools for mitigating and predicting manufacturing imperfections generated during the fabrication of optical and electronic components. This overview page is meant to give a brief introduction to the stages through which each design must pass from circuit schematic to finished, physical semiconductor chip, and the roles these tools play at each stage.

In its ‘Higher Education Program’, under the heading of Calibre Manufacturing tools, the Mentor Graphics company groups two tool types: Resolution Enhancement Technology (RET) and Mask Data Preparation (MDP), the latter including the company’s FRACTURE modules.

The tool flow from the student’s schematic and layout environment through to the finished device as handled by the Calibre CAD suite is shown in Figure 1.

Figure 1. Complete Process Flow on the Calibre Manufacturing Tool Platform; image taken from Reference 1.

Figure 2. The main window of Calibre WORKbench.

Calibre RET Tools

This group includes the main windows LITHOview and WORKbench. In these windows, a user may invoke the different tools or custom scripts to manipulate layout files or generate etching and resist pattern models.

Figure 3. How Calibre WORKbench and Calibre LITHOview work together; image taken from Reference 2.

Calibre Tool Name Function Start Command

This is a model and design-based simulator for the following steps:

  • Simulating aerial and resist images with supplied optical and process models (resist and etch models together are known as process models);
  • Visually inspecting fragmentation schemes for Optical Proximity Correction (OPC);
  • Testing the simulated effects of small modifications to a design file.



Similar in nature to LITHOview, WORKbench also adds a model creation suite that does the following:

  • Optical models via the Optical Model Tool and an underlying configurable optical model file;
  • Process (resist and etch) models through certain tools (the VT5 and CM1 Center tools);
  • Test pattern creation tools, for use in taking real lithography measurements on test chips;
  • Performing Optical Proximity Correction (OPC) on loaded design files.


 For productive use of these Calibre RET CAD tools, the following are recommended:

  • Calibrated optical and resist models for the process of choice;
  • A design file on which to run simulations;
  • Familiarity with these Calibre viewers or tuning tool flows and OPC corrections; and
  • Familiarity with Standard Verification Rule Format (SVRF) and the languages used by the particular tools.

It is possible to use the RET Flow Tool without these files or knowledge, but a mismatch between layouts, models, and setup files will produce poor results.

Calibre MDP Tools

The Calibre Mask Data Preparation suite is a collection of command-line-based tools used to generate, correct, verify and analyse photomask layouts. There is a viewer at the heart of the RET and MDP suites, called Calibre DESIGNrev, around which the more sophisticated editors/viewers are built.

Figure 4. Layout viewers in Mentor Graphics’ Calibre CAD suite; image taken from Reference 4.


Figure 5. The main window of the Calibre MDPviewer.

Calibre Tool Name Function Start Command
A GUI Interface that allows users to run the Calibre FRACTURE tools, the DESIGNrev rule checking, Tcl programming language scripts or macro commands.


A special subset of Calibre MDP tools convert layer data into formatted data for specific manufacturers. These tools contain the word FRACTURE in their titles.

The FRACTURE toolset: A user defines as input to the FRACTURE Standard Verification Rule Format (SVRF) a rectangular section of a Calibre polygon layer. The polygons on this layer are optionally modified and converted to trapezoids. The polygons or trapezoids are then transformed to new co-ordinate and unit systems, and rearranged into the hierarchy of the requested format. These polygons or trapezoids are finally output in the FRACTURE format.

The SVRF rule file used to invoke this fracturing software must conform to all the requirements of such an SVRF rule file. For a complete description of these requirements, refer to the Standard Verification Rule Format (SVRF) Manual (Reference 5) that accompanies each release of Mentor Graphics’ Calibre suite.

Note that the supported versions of each format depend upon the Calibre release version.


Specific FRACTURE Tool Supported Format(s)


All these references are supplied with an installation of Mentor Graphics’ Calibre.

  1. “Calibre Mask Data Preparation User’s and Reference Manual, Software Version 2017.1”. 
  2. “Calibre WORKbench User’s and Reference Manual, Software Version 2017.1”.
  3. “Calibre WORKbench: RET Flow Tool User’s Manual, Software Version 2017.1”.
  4. “Calibre MDPview User’s and Reference Manual, Software Version 2017.1”.
  5. “Standard Verification Rule Format (SVRF) Manual, Calibre 2017.1”.
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