SIITME2009 - 15th International Symposium for Design and Technology of Electronics Packages

Electrical/Mechanical/Thermal Design Integration

Lucian Man!' , Dan Pitica", and Monica Zolog!)

I) Applied Electronics Department, Technical University ofCluj-NapocaCluj-Napoca, Romania

Lucian.Man@ael.utcluj.ro

Abstract: The Intermediate Data Format (IDF) is a specification designed to provide a neutralrepresentation for exchanging printed circuit assembly (PCA) data among mechanical design(MCAD), PCA layout (ECAD), and physical design analysis (MCAE) applications. Powerful analysissoftware, like Ansys, Maxwell, Semcad, Altium Designer or SolidWorks - Circuit Works, can importthe idffiles and use the model for electromagnetic or thermal analysis. The information can also beused for a mechanical approach.

1. INTRODUCTION

The electronic data exchange is a very importantlink to integrate PCB electrical layout, analysis andmechanical design. The IDF - Intermediate DataFormat - is the most used file format for exchangingprinted circuit assembly (PCA) data betweenelectrical and mechanical CAD/CAE systems and forallowing users of these systems to participateconcurrently in the design of electro-mechanicalproducts.

Initially developed in 1992, the IDF has sincebecome a de facto industry standard, implemented bymost CAD vendors and widely used by theircustomers.

The article provides an introduction to the IDF, anoverview on the processes of Integrated DesignAnalysis (IPD) and examples of design iterationsbetween Mechanical Computer-Aided Design(MCAD) and Electrical Computer-Aided Design(ECAD) systems with tools to simplify the dataexchange.

2. THE INTERMEDIATE DATA FORMAT

Excellent data exchange standards exist forcommunicating raw 3D geometric data such as IGES,DXF, STL and more rich data formats such as STEP.However, with the exception of STEP, none of these

standards go much beyond geometric data and areunsuitable for the application specific data exchangerequired for PCA design. For example , thermal dataand component attributes are not part of any of thesedata standards. STEP AP210 for PCA data exchangeis an exception to this. The difficulties with AP2 10are that it is a very complex and data richspecification and, secondly, it is currently supportedby very few MCAD or ECAD vendors. In addition,AP2 10 does not define a means of including compactR-C thermal models of components.

The Intermediate Data Format (IDF) is aspecification designed to provide a neutralrepresentation for exchanging printed circuitassembly (PCA) data among mechanical design(MCAD), PCA layout (ECAD), and physical designanalysis (MCAE) applications, bridging the existinggap.

Fig. 1. IDF purpose [1]

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SIITME2009 - 15th International Symposium for Design and Technology of Electronics Packages

2.1. Overview: IDF 4.0 versus 2.0/3.0 Format

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c)Tab. l. IDF 2.0 / 3.0 / 4.0 [I]

978-1-4244-50330309/$26.00 ©2009 IEEE 162 17-20 Sep 2009, Gyula , Hungary

SIITME2009 - 15th International Symposium for Design and Technology of Electronics Packages

not necessarily come from shortening a particulardesign task but rather by integrating design teams,applying concurrent engineering principles, andcompressing the design-thru-manufacturing-thru­maintenance process as a whole . For example, anelectronic product design team may spendconsiderably more time performing thermal analysisup front in the design process in order to save muchmore time later when designing, prototyping, andtesting the final product design. The more rigorousthermal analysis may also reduce field failures. Theadditional time spent on analysis or 3D design andassembly are small compared to these savings.

Integrated Product Design (IPD) is the key toshortening electronic product design schedules andgett ing to the market faster than the competition. Oneof the difficulties is linking together the differentMCAD, ECAD and CAE (analysis) softwarepackages used by engineers and designers. At theheart of most electronic products is copper-clad FR4based printed circuit board assemblies.

The PCA design touches all aspects of the productdesign process ; examples include mechanical andelectrical packaging, schematic capture, componentplacement, board routing , thermal engineering andEMI (See Figure 2).

IDF 4.0 includes all information that is commonlyshared among mechanical design, circuit boardlayout , and physical analysis during the design andanalysis of products containing PCAs including:

• Each of the major interconnect technologies(traditional PCB, MCM, hybrid);• Panel and board assemblies;• Board design variants;• Panel, board, and component parts;• 3D part shapes consisting of extrusions, cutouts, andcavities;• Mount ing side and opposite side component partshapes ;• Holes (mounting, tooling , pin, via, thermal via);• Conductors (pads, traces, filled areas);• Restriction regions (keepins and keepouts);• Graphics (to represent miscellaneous board featuressuch as fiducials and silkscreen);• Annotations (to communicate miscellaneous designinformation between designers);• Figures, footprints, and sublayouts (to group relatedfeatures and component instances);• Properties (thermal and structural).

IDF 4.0 does not provide a full product or designrepresentation of a PCA. It is not intended to:

• Provide a full functional or electrical description ofthe PCA;• Provide a means of converting PCA designs fromone ECAD system to another;• Provide a means for archiving PCA designs ;• Provide a complete means for manufacturing,assembling, testing, or creating detaileddocumentation of a PCA.

Due to the changes in data content and file format,IDF 4.0 is neither upward nor backward compatiblewith IDF 3.0 nor previous versions. However, thecontent of IDF 2.0 and 3.0 can be fully represented inIDF 4.0 (see Table I).

IPeA LAYOUT I

Route the Board

I ANALYSIS I 1 ~IANUFACTURIN~~NGINEERING

Crutethl!'manufacturine:Documentation

3. INTEGRATED PRODUCT DESIGN

Electronic and mechanical engineers and designershave been using CAD tools for more than a decade.Implementing CAD tools, and, in more recent years,3D part and assembly design tools, have been key toshortening design-to-manufacturing schedules.Interestingly, most of the time and costs savings do

Fig. 2. General PCB design integration process [3]

4. DESIGN UPDATE: MCAD - ECAD - MCAE

Examples of the IDF used in different situationsand different software (OrCAD Layout, CircuitWorks, Solid Works, Ansys, View3D) are shown inFigure 3.

978-1-4244-50330309/$26.00 ©2009 IEEE 163 17-20 Sep 2009, Gyula, Hungary

SIITME2009 - 15th International Symposium for Design and Technology of Electronics Packages

OrCAD Layout Circuit Works Solid Works

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Fig. 3. a), b) OrCAD Layout - Circuit Works - Solid Works

c) Thermal analysis by CADGraphicsWest Incorporated (Circu itWorks/SolidWorks - Ansys)

d) Solid Works - View3D

978-1-4244-50330309/$26.00 ©2009 IEEE 164 17-20 Sep 2009, Gyula, Hungary

SIITME2009 - 15th International Symposium for Design and Technology of Electronics Packages

..._u.'_>ECAD to !\'ICAD Thermal/flow anal sis

IDF ~ "O IDF3.0 IDF ~.O

Pro/Engmeel" ./ ./ ....NXPCB ./ ./ ./OI"CAIl Layout ./ ./ XMentol"Gm p hics I PAIls ./ ./ ....View31l ./ ./ ....Circui t ' ''odi:S I Solill " 'Ol"ks ./ ./ ....Solid Edge III F M odelel" ./ ./IDF Modeler COl' Alrium Design ./ ./CST Stu dio ./ ....AlltOCAIl ./ ....Tab. 2. IDF supported versions (authors' point of view)

REFERENCES

As a major disadvantage, the 4.0 version is notfully supported yet (as input/output data) by themajority CAD tools.

[I] D. Kehmeier, "An Overview of IDF 4.0", IntermediusDesign Integration Bringing Electrical andMechanical Design Together, Intermedius DesignIntegration, LLC presentation

[2] D. Kehmeier, "An Introduction to IDF 4.0 and What itCan Do for You", Intermedius Design Integration, LLC

[3] Mouloud Bourbel, "Electronic Information Exchange" ,Maya Heat Transfer Technologies Ltd.

[4] www.cadgraphicswest.com

[5] Free, A., Kehmeier, D., Agonafer, D., "Driving PCAThermal Analysis Using IDF 4.0 Data Exchange",ASME InterPACK Conference, San Jose, CA, June1999

Fig. 3. e) Example ofa thermal/flow analysis using IDF-based data exchange [3]

content, representation and format. It is neitherupward nor backward compatible with IDF 2.0 nor3.0. It provides an excellent opportunity for theengineering community to implement a data standardfor PCA product representation and allows MCADand ECAD vendors to share PCA product models andprovides real process integration.

4.1. Circuit Works - Why?

CircuitWorks for SolidWorks uses the ComponentLibrary to store informat ion about the SolidWorksmodels it uses to represent electrical computer-aideddesign (ECAD) components when it builds aSolidWorks assembly. Each time an ECAD file isloaded into CircuitWorks, the library is checked tosee if the SolidWorks model already exists. If it doesexist, CircuitWorks will insert the component into theassembly. If the component does not exist,CircuitWorks will create a new component using thefootprint and height information contained in theECAD data .

IDF 4.0 is based on IDF 2.0 and 3.0, which aresupported by all major MCAD/ECAD tools vendors ,but includes significant changes with respect to

As a stand-alone product, CircuitWorks is anintuitive tool for viewing, editing, and translating filescreated by ECAD systems. CircuitWorks reads andwrites industry standard IDF and PADS (.ASC).CircuitWorks can display the board outline,components, holes, keep-out and keep-in areas, aswell as notes from the ECAD data. With IDF v4.0,even pads, filled areas, and traces are shown. Oncethe ECAD data is open in CircuitWorks, changes tothe data can be made. Components may be moved,filtered out, and features such as reference designatorscan be edited if necessary. Changes made to theimported file can be saved out in the IDF format foruse in the original PCB design software.

5. ADVANTAGES AND DISADVANTAGES OF USINGIDF4.0

978-1-4244-50330309/$26.00 ©2009 IEEE 165 17-20 Sep 2009, Gyula, Hungary