IPC-D-279 EN.pdf - 第4页

Acknowledgment Any Standard involving a complex technology draws material from a vast number of sources. While the principal members of the SMT Design Reliability T ask Group of the Product Reliability Committee are show…

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IPC-D-279
Design Guidelines for
Reliable Surface Mount
Technology Printed Board
Assemblies
Developed by the SMT Design Reliability Task Group (6-10b)
of the Product Reliability Committee (6-10) of the Institute for
Interconnecting and Packaging Electronic Circuits
Users of this standard are encouraged to participate in the
development of future revisions.
Contact:
IPC
2215 Sanders Road
Northbrook, Illinois
60062-6135
Tel 847 509.9700
Fax 847 509.9798
T
HE
I
NSTITUTE FOR
I
NTERCONNECTING
AND
P
ACKAGING
E
LECTRONIC
C
IRCUITS
Acknowledgment
Any Standard involving a complex
technology draws material from a
vast number of sources. While the
principal members of the SMT
Design Reliability Task Group of the
Product Reliability Committee are
shown below, it is not possible to
include all of those who assisted in the
evolution of this standard. To each of
them, the members of the IPC extend
their gratitude.
Product Reliability
Committee
SMT Design Reliability
Task Group
Technical Liaison of the
IPC Board of Directors
Chair
Werner Engelmaier
Engelmaier Assoc., Inc.
Chairs
Nick Virmani
Unisys-NASA/Goddard
Space Flight Center
and Ed Aoki
Hewlett-Packard Company
Stephen Wohlgemuth
Photocircuits
SMT Design Reliability Task Group
Amick, Patricia, McDonnell Douglas
Aerospace
Aoki, Edward Masami, Hewlett
Packard Laboratories
Barela, Phillip, Jet Propulsion
Laboratory
Bevan, Matthew, Johns Hopkins
University
Branch, Howard, Smiths Industries
Bright, Burton, Adtran Inc.
Burg, John, 3M Company
Burt, Ronald, Jet Propulsion Laboratory
Carroll, Thomas, Hughes Aircraft Co.
Clifton, Lori, Hewlett Packard Co.
Collins, Henry, Amp Inc.
Colokathis, Elaine, Exotic Plating Lab
Inc.
Croce, Samuel, Litton Aero Products
Division
Currier, Charles, Ambitech Inc.
Currier, Dal, Ambitech Inc.
DiFranza, Michele, The Mitre Corp.
Dunn, Barrie, European Space Agency
Dunn, Linda, Compaq Computer
Corporation
Engelmaier, Werner, Engelmaier
Associates Inc.
Gandhi, Mahendra, Hughes Aircraft Co.
Gonzalez, Constantino, ACME Assembly
Contract Manufacturing Engineering
Gray, Foster, Texas Instruments Inc.
Grosskopf, Curtis, IBM Corp.
Harford, Lyle, Texas Instruments Inc.
Hawken, David, IBM Corp./Endicott
Electronic Packaging
Hersey, Ralph, Lawrence Livermore
National Lab
Hinton, Phillip, Hinton PWB
Engineering
Hymes, Les, Les Hymes Associates
Johnson, Kathryn, Hexacon Electric
Company
Kotecki, George, Northrop Grumman
Corporation
Long, Andrea, Lucent Technologies Inc.
Maguire, James, Boeing Defense &
Space Group
McCluskey, Patrick, University of
Maryland
Moffitt, James, EMPF
Nelson, David, Adtran Inc.
Nicewarner, Earl, Orbital Sciences
Corporation
Officer, R. Bruce, Sanders, A Lockheed
Martin Co.
Olsen, Richard, Continental Circuits
Corp.
Payne, Ron, Olin Aerospace Company
Pepersack, Cindy, NASA/Goddard
Space Flight Center
Reddy, Srirama, AT&T Interconnect
Center of Excellence
Redinger, Vicki, EFW Inc.
Rietdorf, Bruce, Hughes Defense
Communications
Robb, Jeff, Lockheed Martin
Astronautics
Rosser, Jerald, Hughes Missile Systems
Co.
Rumps, Don, Lucent Technologies Inc.
Samples, Wesley, EFW Inc.
Saunders, Penny, NASA Johnson Space
Center
Savage, Robert, The Bergquist
Company
Smith, E. Lon, Lucent Technologies
Inc.
Solberg, Vern, Tessera Inc.
Virmani, Nick, NASA/Goddard Space
Flight Center
Wasler, David, Jet Propulsion
Laboratory
Witzman, Sorin, NORTEL
Special Note of Appreciation
A special note of appreciation goes to the following principle members of the committee who initiated and contributed
significantly to make this document possible.
Vern Solberg, Tessera
Werner Engelmaier, Engelmaier Associates
IPC-D-279 July 1996
ii
Table of Contents
1.0 SCOPE...................................................................... 1
1.1 Purpose................................................................. 1
1.2 Design Philosophy............................................... 1
1.2.1 Establishing the Design Team............................. 1
1.2.2 Defining Reliability Requirements...................... 1
1.2.3 Understanding the Product Life Cycle................ 1
1.2.4 Defining the Product Environment...................... 2
1.3 Document Organization....................................... 2
1.3.1 Applicable Documents......................................... 2
1.3.2 Design for Reliability of SM Assemblies........... 2
1.3.3 Substrates ............................................................. 2
1.3.4 Components.......................................................... 2
1.3.5 Attachment Materials and Coatings.................... 2
1.3.6 Assembly Processes and DfM............................. 2
1.3.7 Testing.................................................................. 3
1.4 Terms and Definitions.......................................... 3
2.0 APPLICABLE DOCUMENTS .................................. 5
2.1 Institute for Interconnecting and Packaging
Electronic Circuits (IPC)..................................... 5
2.2 Electronic Industries Association ....................... 5
2.3 Joint Industry Standards...................................... 5
3.0 DESIGN FOR RELIABILITY FOR SURFACE
MOUNT ASSEMBLIES
............................................. 5
3.1 Life Cycle Environment...................................... 5
3.1.1 Manufacturing Processes..................................... 5
3.1.2 Processing Temperature Excursions.................... 5
3.1.3 Burn-In and Environmental Stress Screening
(ESS).................................................................... 6
3.1.4
Transport .............................................................. 6
3.1.5
Storage.................................................................. 6
3.1.6
Use Environments................................................ 6
3.1.7
Environmental Stresses........................................ 7
3.1.8
Temperature/Thermal........................................... 7
3.1.9
Cyclic Temperature Swings................................. 7
3.1.10
Thermal Shock..................................................... 7
3.1.11
Electrical ............................................................. 8
3.1.12
EMC/EMI............................................................. 8
3.1.13
Mechanical Shock and Vibration ........................ 8
3.1.14
Insulation Resistance .......................................... 9
3.1.15
Solvent Compatibility........................................ 10
3.1.16
Corrosion............................................................ 10
3.1.17
External Radiation ............................................. 10
3.1.18
Space Environment............................................ 10
3.2
Thermal Design.................................................. 10
3.3 Printed Board Design and Layout..................... 10
3.3.1 Thermal Design and Layout.............................. 11
3.3.2 Thermal Design and Conformal Coating.......... 11
3.3.3 Land Patterns ..................................................... 11
3.3.4 Balance About Neutral Axis.............................. 11
3.3.5 Vias..................................................................... 11
3.3.6 Printed Board Trace Widths and Spaces........... 11
3.3.7 PTH and PTV Thermal Isolation/Relief ........... 12
3.3.8 Test Pads ............................................................ 12
3.3.9 Spacing Between Parts...................................... 12
3.3.10 ‘‘Pads-Only’’ Design.......................................... 12
3.3.11 Components with Reduced Clearances
(Traces Under) ................................................... 13
3.3.12 Components with Reduced Clearance and
Open Vias........................................................... 13
3.4 Coefficient of Thermal Expansion (CTE)
and CTE-Mismatch............................................ 13
3.5 Solder Joint Reliability...................................... 14
3.5.1 Primary Design Parameters............................... 14
3.5.2 Secondary Design Parameters........................... 15
3.6 Plated-Through Hole and Via Reliability ......... 16
3.7 DfR of SM Solder Attachments........................ 16
3.8
DfR of Insulation Resistance ............................ 16
4.0 SUBSTRATES ........................................................ 16
4.1
General Substrate Categories ............................ 16
4.2
Substrates and Their Functions:........................ 16
4.3 Moisture and its Effects on Polymer
Substrates ........................................................... 17
4.4 Coefficient of Thermal Expansion (CTE) of
Polymer Systems................................................ 17
4.5
Constraining Cores in Substrates...................... 17
4.5.1
Printed Board Stiffness and Damping............... 19
4.6 Flexible Printed Board with Metal
Support Plane..................................................... 19
4.7 Discrete Wire Structures with Metal Support
Plane................................................................... 19
4.8
Outgassing of Polymer Substrates .................... 19
4.9 Assembly Process Effects on Polymer
Substrates ........................................................... 19
4.10
Printed Board Solderability............................... 19
4.11 Design for Reliability of Plated-Through-Hole
Vias (PTVs)........................................................ 19
5.0 GENERAL COMPONENT SELECTION
CONSIDERATIONS
................................................ 19
5.1
Component Selection Strategy.......................... 20
5.2
Package Leadframe and Local Materials.......... 20
July 1996 IPC-D-279
iii