Why do temperature-based FEA? Natalie Hernandez, PhD Product - - PowerPoint PPT Presentation

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Why do temperature-based FEA? Natalie Hernandez, PhD Product - - PowerPoint PPT Presentation

Mar 19, 2024 284 likes •579 views

Why do temperature-based FEA? Natalie Hernandez, PhD Product Manager, Sherlock 1 9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com In a perfect world, your PCBA is in a perfectly controlled, relatively

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

Why do temperature-based FEA?

Natalie Hernandez, PhD Product Manager, Sherlock

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

In a perfect world, your PCBA is in a perfectly controlled, relatively benign environment

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  • Humidity control
  • Temperature monitoring
  • No vibration
  • No shock events
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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

WHAT’S THE PROBLEM?

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

We are not in a perfect world!

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dynamic amic extreme me

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

Increasing number of companies reporting early life failures during the manufacturing process or during testing or in the field

UNEXPECTED SOLDER FAILURES

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Classic solder fatigue approaches do not seem to be capturing these risks

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

WHAT’S THE CAUSE?

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

  • A. We use lots of different materials
  • Semiconductors, Ceramics, Metals, Polymers
  • B. We bond these different materials together
  • Plating, Solder, Adhesive
  • C. These materials expand/contract at different rates

Why do electronics fail when they experience temperature changes?

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

Why do electronics fail when they experience temperature changes?

  • Two different expansion/contraction behaviors
  • Because solder is connecting two materials that are expanding / contracting

at different rates (GLOBAL)

  • Because solder is expanding / contracting at a different rate than the

material to which it is connected (LOCAL)

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

Why do electronics fail when they experience temperature changes?

  • This differential expansion and contraction introduces stress into the solder joint
  • This stress causes the solder to deform (aka, elastic and plastic strain)
  • The extent of this strain

(that is, strain range or strain energy) tells us the lifetime of the solder joint

  • The higher the strain, the

more the solder joint is damaged, the shorter the lifetime

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

Drivers for Solder Joint Thermo-Mechanical Failures

Knowing the critical drivers for solder joint fatigue, we can develop predictive models and design rules

CTE of Board Elastic Modulus (Compliance) of Board

CTE of Component Elastic Modulus (Compliance) of Component Length of Component Volume of Solder Thickness of Solder Solder Fatigue Properties

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

OVER-CONSTRAINED BOARDS

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Let’s throw system-level effects into the mix…

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

COATING/POTTING/UNDERFILL

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 

           

2 2 1 1 1 2

1 1 E A E A T F  

Let’s throw system-level effects into the mix…

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

MIRRORING

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Meifunas, M., et al. "Measurement and prediction of reliability for double-sided area array assemblies." Electronic Components and Technology Conference, 2003. Proceedings. 53rd. IEEE, 2003.

Based on Darveaux Model

* *

Based on Darveaux Model

Ye, Yuming, et al. "Assessment on reliability of BGA package double-sided assembled." High Density Packaging and Microsystem Integration, 2007. HDP'07. International Symposium on. IEEE, 2007.

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  • Avoided in earlier designs (challenges with rework

and X-ray inspection)

  • Increasingly required due to higher densities and higher

speed memory

  • Reduces lifetime by 2X to 4X, but numerous
  • rganizations struggle to predict behavior

Will underfilling the BGA help?

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

WHAT’S THE SOLUTION?

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

Temperature-based FEA

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  • Facilitates the assessment of system-level effects due to thermal and vibrational
  • stresses. This is exceptionally important for the automotive and aerospace industries.
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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

Example Problem

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http://dx.doi.org/10.1109/ICEP.2016.7486818

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

Example Problem – 3D Model

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

Example Problem: Incorporating temperature dependence

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Temperature-dependent Laminate properties: Elastic Modulus

Temperature Elastic Modulus

  • 55

27000 25 24804 125 17000

Temperature-dependent Solder properties: Elastic Modulus and CTE

Temperature Elastic Modulus

  • 100

38941.1 2.37e-5 150 18996 2.59e-5

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com Temperature (C) Frequency (Hz)

  • 55

781 761 25 752 105 661 220 475

Natural Frequency Results

19 100 200 300 400 500 600 700 800 900

  • 100

100 200 Natural Frequency (Hz) Temperature (C)

NATURAL FREQUENCY

Temperature

220C

  • 55C

0C 25C 105C

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

Experimental and Simulated first mode shape at 105C

20 http://dx.doi.org/10.1109/ICEP.2016.7486818

1st Natural Frequency: 663Hz

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

Harmonic Vibration

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105C Damage: 8.4E2

  • 10C

Damage: 5.8E1

There is a clear decrease in damage as temperature decreases.

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

WHY DO TEMPERATURE-BASED FEA?

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

  • Unless you’re in a perfectly controlled, benign environment, there will be

combined events impacting the PCB.

Why do it?

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

WHY DO IT IN SHERLOCK?

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

  • Users can quickly model their boards and run temperature-based FEA

with/without using Ansys or Abaqus.

  • Sherlock provides more accurate Fatigue predictions.

Can current FEA tools provide fatigue predictions? NO

Why do it in Sherlock?

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

  • Understanding the responses of your PCBAs under today’s environmental

stressors is key to answering that ultimate question, “When will my board fail?”

Summary

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

  • Humidity-driven Failure Modes
  • Via Fatigue Predictions
  • SolidWorks Integration

Looking ahead… Key Features in Sherlock 6.0:

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

Thank you for listening!

Questions?

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9000 Virginia Manor Rd Ste. 290, Beltsville MD 20705 | 301-474-0607 | www.dfrsolutions.com

  • Dr. Natalie Hernandez, Product Manager, Sherlock
  • nhernandez@dfrsolutions.com
  • Mark Musitano, Senior Sales Engineer
  • mmusitano@dfrsolutions.com

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