Electromigration Analysis in ANSYS SIwave

You’re welcome, it’s 11 a.m., so I’ll get going. Today’s Ozen Engineering webinar topic will be electromigration analysis in ANSYS SIwave. This is Chris Cowan, here to give a quick introduction to Ozen Engineering.

Stephen and Chang Liu will be delivering the content on the electromigration analysis. A quick note, we’ll be presenting similar content at the upcoming ANSYS conference, the ANSYS Innovation Conference, which will be held on September 4th in Santa Clara.

You can register to join that on our website, and we’ll look forward to seeing you there. Ozen Engineering is a company focused entirely on simulation. We use multi-physics finite element analysis, computational fluid dynamics, and high/low-frequency electromagnetics tools.

As the recent America’s ANSYS Channel Partner of the Year, we sell the full suite of ANSYS software products, provide training, technical support, and engineering consulting services related to 3D design, structures, fluids, electronics, and semiconductor.

We also offer cloud services, including ANSYS cloud and OzenCloud. If you’re interested in any of this, please contact us. You can see our list of upcoming webinars here. We have scheduled every week or every other week through November.

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And if you’d like to receive updates on upcoming webinars, please subscribe to our newsletter. We send out an email once a month. One thing I’d like to tell you about is the cloud, the ANSYS cloud. It’s a new product that ANSYS released.

It’s currently accessible natively through ANSYS Mechanical, Fluent, and Electronics products.

The benefits of working with ANSYS cloud include one-click burst to the cloud for compute resources, online post-processing through the cloud, and a single solution built natively into the tools optimized for the ANSYS solvers. If you’re interested in trying this out, please let us know.

And we can arrange a free one-month trial of ANSYS cloud. Our presenter, Anchong Steven Liu, holds a BS from UC Santa Barbara with an emphasis on signal processing and digital imaging processing.

For technical support questions related to electronics product suite, you’re most likely to be familiar talking with Steven. So with that, I’m going to turn it over to Steven. Thanks, Chris. Today’s topic will be electronics and the electrical migration in SL Wave.

We’ll go through an overview of free electron migration, physical explanation, as well as the Pulak’s equation. We’ll take a look at how the Pulak’s equation is being implemented in the SL Wave 2019 R1 version. We’ll talk about being arbitrary and how we handle this total in other forms.

Electron migration usually takes place in solid-state metals when the metals are stressed, and high current densities, along with high temperature above about 100 degrees Celsius.

This phenomenon results in steady change of conductor dimensions, causing damage in terms of voids or hillocks in the integrated circuit. The term electromigration was created by Professor Tolbert Huntington in the late 19th century.

The term electromigration was created by Professor Tolbert Huntington in the late 19th century. The term electromigration was created by Professor Tolbert Huntington in the late 19th century. The term electromigration was created by Professor Tolbert Huntington in the late 19th century.

Because he did not like the German use of the word electro transport. So with the electromigration will be introduced Black’s equation. It’s developed, this equation is developed by Jared Black.

It’s a model to, it’s a equation that to model and estimate the medium time to failure of a conductor due to this electromigration phenomenon. He published this model in a seminar in 1969 paper in IEEE transactions on electron devices.

So this is the, this is what the Black’s equation looks like. So MTF stands for medium time to failure in hours. It’s in proportional to a couple parameters or variables here. A represents experimental constant. J is the current density. I is activation energy.

K represents Boltzmann’s constant. And T represents a temperature. In SL-Wave, we have the capability to coupling the results with IcePak to give you a temperature plot. So in order to do such an electromigration analysis, you have to have a DCIR drop simulation done first.

Let’s take a look at a case study in electromigration analysis in SL-Wave. The two key areas are solder bumps in this chip package, and also whether it’s R-Wave or R-Wave. In this case, the two key areas are solder bumps in this chip package, and also whether it's R-Wave or R-Wave.

Only process and this silver is useless in the culture. For R-Wave it's cost paying costs. Now we have this package design and all we need to do is to set up a DCIR simulation and run this module called EMMTTF, which is the module that computes electromigration-induced failures.

Once you hit on that button, you will have this window popped up that you can, this dialog box pop up, that you can have, you can manipulate your material property for their experimental constant as well as activation energy. Can also specify the PCOS constant value for N. Once you’ve done that.

And also you can specify whether the warning and the error criteria for the meantime to failure. As you can see in this case, the warrant is set to 9,000 hours for warning and 45,000 hours for error.

Meaning that if the result comes out that the meantime to failure is less than 9,000 hours on certain times. So if you have certain areas or components, it will give you a warning. If it is less than 45,000 hours, it will give you an error.

The meantime to failure, on the left is the meantime to failure plot. On the right is the current density. The current density is, is plot. And the current density is, is the current density. So the current density is, is the current density.

And the current density is the voltage drop of that plate. And the current density is, is the current density and the voltage drop of that plate. So this is the current density and the voltage drop of that plate. Each component is plotted based on the DCIR drop simulation.

So it, it calculates the current density, the voltage drop on all, all of the components in this package. As you can see, the current density is pretty high on in the middle area, on the, some certain, So without any surprise on those areas, the mean time to failure is higher.

Sorry, the mean time to failure is lower. So that gives you a red spot. So those are areas that we need to pay more attention to. We can also change the plot legend to MTTFT warnings and violations based on the criteria we defined.

So as you can see, the Vs, the Vs and the bound wires in the middle are the ones that really need some kind of attention. We can also individually plot. The MTTFT and the current density on the Vs. Same idea. We can also see the violations, violations warnings on the Vs as well.

For the RDL, that’s a second case. In this case, we only have a copper material. We set the same criteria for the warning and the error. So we can see that piecewise constant value is unchanged.

Uniform temperature, as you can see, the current density from the DCR simulation is taken from one of the simulations that we’ve done previously. And we apply a uniform temperature of 85 Celsius. Same idea. Mean time to failure plot on the left. Current density plot on the left.

And we apply the uniform temperature of 85 Celsius. And we apply guests on the right to see the change in temperature of these elements in defense of temperature as the more efficient LDL is, height and stereotypes.

You that SL-WAVE 2019 R1 release has this electron migration mean time to failure calculation based on a modified version of the Black’s equation. It is based on experimental constants.

Design trouble, it can spot the design trouble spots can be, design trouble spots can be identified in solder bump and the chip scale package geometries. So let’s take a look at the actual SL-WAVE simulation. So this is one of the RDL examples we had before.

So as we said before, we need to define a DCIR simulation prior to the electron migration analysis. So we can plot we can plot the the via current as well as the current density, also the voltage on the on the trait on load on the component. Also the power density.

So once so this is this is this is easily manipulate just couple couple clicks for the for this simulation. If we were to start from scratch all you need to do is click on compute DCIR simulation.

This one is we set a uniform design we can change this to 85 as well we had in the so all we need to do is click launch actually we can change this to a new DCIR simulation okay , so it will give you a new a new a new a new a new a new same results well not the same results the the ambient temperature has been changed so we can take a look at the current densities on the on the component, on the VS and the traces.

Then after that, we all need to do is click on this compute EMM TTF. This will give you, this will have the dialog box popped up as we saw in the slide. So we just launch it based on the DCR simulation we just had. I’ll cancel this one for now because we already have one implemented.

So we see that there are some red spots on this traces and on these interconnections. So this will help you quickly identify where the red spots are. Where are the spots that needs to pay attention to. Yeah, so that is pretty much it for today’s topic.

As Chris introduced earlier, we’ll have a ANSYS conference next Wednesday on September 4th in Sunnyvale or San Jose. The location is the Hyatt Hotel near the Levi's Stadium. During that conference, our principal will give a more extensive presentation on the electromigration topic.

Not only in SL-WAG, the environment, but really how the physics and equations are being implemented. Yeah. And how he does that. How he accounts for different aspects of electromigration. As we know, the electromigration consists of, is caused or consists of four different aspects.

It’s electromigration, thermomigration, stress migration, and some modification based on the atomic concentration. So that’s a more complicated model to implement. And that’s in the mechanical, ANSYS mechanical environment.

The SI-WAVE environment just gives you a easier and more straightforward way to get the results. For the meantime to failure. So, yeah, without any further ado, that will be all I have for today’s webinar. Okay, seems we’re all good for now. So thanks for joining the webinar today.

Thanks for your attention, everybody. Have a nice day.