Global SMT and Packaging Interview with Dr. Subodh Kulkarni at APEX 2020

Dr Subodh Kulkarni, President and CEO of CyberOptics, discusses with Trevor Galbraith, Editor-in-Chief of Global SMT and Packaging, the drivers behind the merging of SMT and semiconductor packaging technologies, and the inspection requirements needed for these demanding applications.

TG: Welcome to CyberOptics here at IPC APEX. I’m delighted to be joined by Dr. Subodh Kulkarni. Nice to see you again, Subodh.

SK: Good to see you Trevor.

TG: We are going to cover a couple of topics about your products. But first of all, I want to talk generally about what is happening with the convergence in the industry between back-end packaging and traditional SMT (Surface Mount Technology). We are starting to see more and more of it, what are you seeing?

SK: Absolutely. We are definitely seeing a convergence of the semiconductor advanced packaging area with SMT. That whole general area is being referred to as ‘advanced packaging’. Clearly what is driving it are things like stacking of chips and fan-in and fan-out packages. The semiconductor industry is struggling showing the transistor in two dimensions, the classic Moore’s Law. Every generation is getting more and more expensive, but suddenly around a few years ago, the semiconductor industry discovered that there is a third dimension to take advantage of –  the Z axis. Once they found out that it is possible to thin down chips and stack them, the value you get is huge compared to the complexity of the stack. Now that whole third dimension is exploding and suddenly skyscrapers are being built by the chip industry. That has led to an explosion of advanced packaging applications, and inspection is critical over there because once you start stacking, you are essentially dealing with extremely thin chips, and any distortion is a huge problem. So they need to inspect each and every bump or pillar, which is essentially the glue between the stacks, and that has led to an explosion of need for 3D inspection and metrology in the advanced packaging area. And, it’s overlapping with SMT. If you take a look at the latest smart phone, iPhone® for instance, and open it up, you don’t find a conventional PCB in it anymore. It is mostly advanced packages that are strung together with some kind of flexible substrate, and that’s exactly how the industry is evolving. I definitely see the convergence happening right in your pocket, right now with mobile devices, and that’s not going to go back. In the future, more and more of our advanced electronics are going to be with advanced packages. SMT and semi is finally merging and it is called advanced packaging.

TG: As I said to you before, we’ve been waiting for this for a long time as well. Now you have a foot in both camps of course, because you have a semiconductor division, as well as a traditional SMT division. Are some of your technologies that you’re developing in the semiconductor side filtering down into SMT?

SK: Absolutely. What we are focused on here is what we call MRS™ Technology, Multi-Reflection Suppression™. It’s a unique way of doing 3D non-contact optical sensing that we pioneered a few years ago, and it is much faster and more accurate than many other conventional, older technologies that some of our competitors are using, like Moiré pattern, those kinds of technologies. With MRS, it is a digital technology, a multi-projector, multi-camera, digital technology. The real secret sauce are the mathematical algorithms that gives us the speed and accuracy. With that, we first got into the semiconductor industry with our partnership with KLA®, who is a big player in semiconductor inspection. That’s how we started commercializing MRS in the semiconductor industry, with a partnership with KLA’s back-end business unit, called ICOS. At the same time, we commercialized our SQ3000™ 3D AOI system on the SMT side. Over time what has happened is with our knowledge of what back-end needs and the merge of semi and SMT, clearly we have what we now call a multi-functional SQ3000 system. It does SPI, AOI as well as Coordinate Measuring Machine (CMM), so its really an in-line CMM tool. With the better resolutions we are getting, we are beginning to approach the back-end, or what is called the advanced packaging area. It is an exciting time for us to be taking advantage of our semiconductor legacy, as well as our SMT legacy, and play in this space right now.

TG: Metorlogy is becoming more and more important in the SMT space, not just for being able to measure a package, but also the auto-programming.

SK: Absolutely, auto-programming is here to stay, people want it, and metrology is a critical part that enables it. Auto programming is not only needed for timesavings, but also to eliminate any human error or variation. Metrology is a key part. People don’t want just a pass/fail report anymore. They want to see the actual numbers to make sure the pass/fail report has some substance behind it. And if something is failing, they need to know what exactly to do and change. They don’t want to just know that it has failed.

TG: You have to be able to also digitize that information for the traceability and to work with the Industry 4.0 systems that are coming out into the market.  

SK: Correct, and there’s the whole AI suite that is beginning to come along in Industry 4.0. AI needs hard data. AI doesn’t need just pass/fail. And for hard data they need measurements, and they need exact variances, accuracies and stuff like that. And that’s AI too. It has become more effective. So I think it is all coming together at the right time to lead to better yields and productivity.

TG: Now one of the areas CyberOptics has been pretty well known for, famous for really, over its history has been its sensor development. What is happening in the latest end of your sensor development?  

SK: We have some exciting things going on in our MRS technology development. As I said, MRS stands for Multi-Reflection Suppression, it’s a unique way of doing 3D non-contact optical sensing that enables us to get better accuracies and speed at the same time, compared to conventional technologies. Now we have commercialized, what I call, the second generation MRS. We call it the NanoResolution MRS Sensor technology for 3D and 2D inspection and metrology. We have developed not only higher resolutions, so now we are down to a 3 micron sensor with MRS, pixel size. But in addition we also have the capability to measure perfectly reflective surfaces, like a silicon wafer or mirror-like surfaces because we can take care of the specular angles as well.

On the show floor here we have a 3 micron 2D sensor that we are showing our customers, and we are getting tremendous interest. We have actually sold a few units already of that 3 micron 2D sensor. Pretty soon you will see us talking about 3 micron 3D with specular dimensions, and by the end of this year you will see our 3D AOI/SPI platform capable of handling perfectly reflective surfaces with better resolution than what we have right now.

TG: It’s scary the sizes you are getting down to, the dimensions you are getting down to. Three microns is nothing- unbelievable.

SK: A human hair is 80 micron in diameter, so we are talking about some seriously small dimensions here. But that’s what you need in the advanced packaging world because the bumps are 30-40 microns each, and the pitch is about the same. And to measure 30-40 micron features accurately with good resolution, you do need a 3 micron kind of resolution.

TG: Well, its fantastic to see how you’re developing these things and staying ahead of the trend. Dr. Kulkarni, thank you for joining us today.

SK: Thank you for your interest, and we look forward to updating you with more exciting announcements soon.

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