New High Voltage Devices Will Change Parametric Test

Many parametric test engineers are learning to cope with high voltage process requirements for new applications such as high brightness LEDs. Not surprisingly, high voltage processes require high voltage parametric testing for process control and reliability monitoring.

Most of yesterday’s device technologies were limited to under 100V. Such devices were easily characterized with existing parametric test systems.

Consider, for example, Bipolar-CMOS-DMOS (BCD) technology. The term BCD is often used to describe a number of variants, including combinations such as CMOS-LDMOS, NMOS-LDMOS, etc. Today, BCD devices have emerged that use LDMOS to support voltages as high as 700V or 800V, demonstrating the upward trend. It’s expected that BCD technologies will exceed 1000V by about 2012.

Such high voltage devices are currently used for applications such has High Intensity Discharge (HID) illumination, where a combination of high voltage and high power is needed. There are a variety of applications for high voltage BCDs, including:

• Industrial controls (motor and actuator control)

• Automotive controls (lighting, engine control, drive train control, etc.)

• Advanced lighting (LED, HID, etc.)

• Power conversion and storage

• Display (backlight)

These devices require special consideration when developing a parametric test strategy. Part of the challenge lies in the fact that the new high voltage requirements add to rather than subtract from the roster of parametric tests. In many if not most cases, the high voltage transistors are controlled by complex logic that requires low voltage/low current parametric test. Consequently, both high voltage and logic tests have to be addressed within the same test plan while minimizing impact on throughput.

The roadmap for BCD technologies and related processes over the next two to five years clearly indicates the need to move beyond 1000V in parametric test. This will pose a number of challenges for high voltage parametric test systems. Instrumentation is likely the least significant of the challenges; however, probing at more than 1500V will almost certainly be much more challenging.

It’s As Much About People as Performance

As much as we engineers feel that pure technology advances trump all, we’re reminded of the powerful impact human nature has on the adoption of the technology we create. I’m returning from a spring break vacation season where it seems that EVERYONE I see in airports and hotels is carrying around either an iPhone or an iPad. While the iPad in particular certainly presents an example of elegant engineering, as a computing device it’s not particularly groundbreaking. There’s not that much you can do with the tablet that you can’t already do with your laptop, and some would even say it offers less functionality than a laptop. Yet its consumer appeal is undeniable. Why? Because of the Apple brand? Perhaps. Actually, I’d point more to the power of the interface as the true breakthrough here. The intuitiveness, the bright screen, the light packaging all combine to appeal to us as humans in ways that can extend far beyond advances in engineering performance. And if we think of past great leaps forward in consumer electronics, they often don’t stem from a performance but rather to interface innovation, such as the circle control wheel on the iPod, the one-click simplicity of iTunes, or even the early Macintosh operating system. There were other offerings that competed with each of the above, and which were sometimes superior from an engineering perspective. However, the more engaging human interface of these examples proved to be the winning advantage.


The test industry should draw (at least) two lessons from this. Of course, the first lesson is that this latest burst of consumer innovation in smart phones, tablets, netbooks, and the like is good for business, because it has coincided with the rise of another generation of ICs that need to be tested. The test industry is driven by innovation in consumer electronics, as every new round of development is accompanied by new cycles of device characterization for the next evolution of chips. Further, Apple’s innovation has shown the semiconductor industry that it’s not a zero sum game – the iPod nano created a whole new category, as did the iPhone, and, most recently, the iPad. Consumer demand doesn’t just shift from a netbook to a tablet – it expands and creates higher volumes of purchases and therefore increases the demand for semiconductors.

The second lesson is that the T&M industry’s attempts to improve instrument interfaces, with touch screens and color displays, is important to our engineering customers, even if they don’t necessarily articulate that during a Voice of the Customer exercise. As people become more comfortable and familiar with these new user interfaces, they expect all their devices – cars, washing machines and even test instruments – to meet the same ease of use standard. We must pay more attention to the way our customers interact with our measurement tools in order to make the tools as powerful and useful as possible.