ANSYS Confidential

35 Pages·2015·2.56 MB·English

by  Ronald A. Santillo

Customer Application Presentation

ANSYS Solution for PCB Reliability
Ankit Adhiya
Vamsi Krishna
Rohit Patchigolla
1 © 2015 ANSYS, Inc. November 12, 2015 ANSYS Confidential
PCB Overview
• A printed circuit board (PCB) mechanically supports and electrically connects electronic
components.
• Printed circuit boards are used in almost all electronic products across industries.
PCB in PCB in
 Controller System  Attendant Controller Panel
 Audio System  Engine control module
 Engine Control Module  ….
 LCD display module
Aerospace and Defense
Consumer Electronics
Automotive
© Baker Hughes
PCB in Drill hole tool
Healthcare
Oil and Gas
2 © 2015 ANSYS, Inc. November 12, 2015 ANSYS Confidential
PCB Reliability
• A reliable PCB can ensure long lasting service and efficient operation of electronic components
• During manufacturing and operation, PCB is subjected to extreme environmental and
operational conditions, which causes reliability issues
DC-IR + Thermal Reliability Thermo-Mechanical Mechanical Reliability
Reliability
(© expertfea.com)
(© Alcatel Lucent, Intel, Sanmina)
Cracks formation at interface Large deformation when PCB
Hot spot on PCB due to trace
between solder ball and PCB subjected to random vibration
heating
due to thermal cyclic loading
3 © 2015 ANSYS, Inc. November 12, 2015 ANSYS Confidential
Content
• DC-IR + Thermal Reliability
• Thermo-Mechanical Reliability
• Mechanical Reliability

4 © 2015 ANSYS, Inc. November 12, 2015 ANSYS Confidential
• DC-IR + Thermal Reliability
• Thermo-Mechanical Reliability
• Mechanical Reliability

5 © 2015 ANSYS, Inc. November 12, 2015 ANSYS Confidential
Background : Joule Heating
• What is Joule Heating?
• Joule heating / resistive heating is the process by which the passage of
electric current ( 𝐼 ) through a conductor of electrical resistance ( 𝑅 )
releases heat ( 𝑄 )
𝑄 = 𝐼2𝑅
• Why do we need to perform thermal reliability
analysis on printed circuit / wiring boards?
• High current PCB’s are densely populated with
components
• Reduction of trace and via dimensions
• Current densities increase
• Joule heating effects on copper traces 
Temperatures increase  Reliability issues 
PCB delamination and failure
6 © 2015 ANSYS, Inc. November 12, 2015 ANSYS Confidential
PCB Thermal Reliability
Predict accurate temperature of PCB
Challenges
Understanding both Thermal and Electrical physics and
applications
Transfer data between different physics for accurate analysis
ANSYS Solution

SIwave transfers local Joule

heating losses into Icepak

Automatic looping until
DC losses & Thermal
map are constant
Icepak returns

temperatures back to
Accurate loss calculation

SIwave
with inclusion of Thermal

effects
7 © 2015 ANSYS, Inc. November 12, 2015 ANSYS Confidential
SIwave-DC – Icepak Bi-direction Coupling
Overview
• Spatial Power Loss information from the DC-IR analysis (SIwave) is
transferred to Icepak as a spatial Joule Heating map (modeled using 2D
sources).
• Spatial Temperature information from the Thermal analysis (Icepak) is
transferred to SIwave and interpreted as spatial thermal modifiers for
electrical conductivity.
8 © 2015 ANSYS, Inc. November 12, 2015 ANSYS Confidential
Siwave DC Solutions
Import Settings
Verify / Modify Geometry,
Materials, and Circuit Elements
Setup Simulation
WorkFlow Wizard, making the Simulation setup more convenient
and user-friendly.
9 © 2015 ANSYS, Inc. November 12, 2015 ANSYS Confidential
Siwave DC Solutions
Quickly Identify:
• High Currents in Vias
• Current Crowding in Copper
• High Power Loss Regions
• Automated report generation with user
defined pass/fail criteria.

10 © 2015 ANSYS, Inc. November 12, 2015 ANSYS Confidential