Electronic Design
The Changing Landscape of Semiconductor Test

The Changing Landscape of Semiconductor Test

Few industries have seen as much change as the semiconductor industry has over the past decade. Fabrication processes have improved from 130-nm capability (which gave us transistors at 1/1000th the width of a human hair), to 32-nm technology today. Intel predicts that process technology will be at 6 nm by 2020. Systems houses which once focused on the PC industry are now driving innovation in consumer electronics and mobile devices. System footprints, integration, and power consumption have all improved dramatically, with more advanced technologies on the horizon.

Change is not driven solely by technology advances, however. Global economic factors also force change. In both the dot-com bubble burst in 2001, and in the current economic recession, semiconductor companies were forced to respond with drastic cost-cutting measures including layoffs and massive restructuring to adjust for changes in the market. Each recession forces semiconductor vendors to take a close look at their organizations and find ways to cut costs in every phase of development, especially in test.

Although chip test is a critical step in the design cycle for semiconductor vendors, it is becoming a much larger percentage of the overall cost of producing an IC. High unit-volume markets like mobile handsets are driving down the average selling price (ASP) of chips even as they become more complex. Changes in semiconductor technology and added device complexity put additional pressures on the test process. Test techniques, including parallel and multi-site testing, have both become standard practices in the industry to help increase throughput and to lower test costs. Many companies also now utilize built-in self-test (BIST) techniques to help lower test requirements by doing many tests internally to an IC.

Traditional chip test solutions are struggling to keep up, and have not seen the same cost reduction as the devices they are testing. The cyclical nature of the semiconductor automatic test equipment (ATE) market has made it difficult for ATE vendors to grow or even maintain their investment in R&D, resulting in less technological and cost-reducing innovation.

While the investment in traditional test equipment has declined over the past decade, PC-based technologies for IC test have come a long way. The last ten years have seen the emergence of multicore computing and high-bandwidth bus technologies such as PCI Express. Test platforms based on PC technologies such as PXI have benefited tremendously from these advancements. In fact, PXI has grown from only a handful of products in 2000 to more than 1500 products today from more than 70 different test vendors. Furthermore, the modular nature of PXI makes it a very convenient, COTS-based chip test platform, allowing semiconductor vendors to pick and choose instrumentation as needed to create cost-effective ATE systems targeted to meet the needs of a specific device under test. New instrumentation including source-measure units and advanced digital I/O now make PXI well positioned to have an impact on the semiconductor industry as well.

While cutting-edge technology such as high-end memory and processors still require the most advanced ATE for complete coverage, PXI provides semiconductor vendors other options when evaluating their test strategy. Instead of investing solely in traditional ATE designed to test least-common-denominator chips, semiconductor companies can use PXI to enhance their production test strategy. Deploying PXI-based ATE systems allows vendors to add to production capacity for common, high-volume products. The compact form factor of PXI also makes it an ideal platform to extend the capabilities of currently deployed ATE systems to add specialized analog or RF measurements as needed. This enables companies to preserve their existing investment in their ATE platform without having to incur a massive cost to upgrade the entire platform when new test capability is needed.

Many larger semiconductor chip vendors already have their own internal test division whose responsibility is to customize their ATE systems and/or to develop their own in-house test platforms as a way to help them reduce test costs for simple or high-volume products. The progress of modular PC-based test platforms now means that anyone can take this approach to help them optimize test costs, and be more competitive and profitable.

While production test equipment dominates the majority of the test costs for a semiconductor device, there are many other areas in your organization where you can optimize your test approach, most notably in characterization. In the lab, engineers need to be able to quickly identify design issues and deliver feedback to the development team. They need to be able to quickly customize and perform automated tests on new silicon to get products to market as fast as possible, while ensuring high product quality. Making sure they are properly trained and equipped with the latest technology is important to reduce test development time.

One trend in the industry is to utilize a software-defined test approach using off-the-shelf programming tools and modular hardware platforms such as PXI to build characterization systems on the bench. PXI systems with software-defined modular instrumentation allow engineers to quickly modify or add in new tests as needed to zero in and isolate any issues found during testing. This approach is valid for both characterization and production, providing a test platform that is more flexible than previous test equipment and one that in some cases can produce dramatic benefits both in terms of test time and cost.

ON Semiconductor is an example of a company who was looking to optimize their test setup with a low-cost solution to increase validation throughput for new product introductions. ON Semiconductor needed an accurate and precise test system with easily upgradable software and hardware for future use that would deliver shortened evaluation cycle time and reduce costs. Using PXI, they were able to achieve a 10X improvement in validation throughput, with a 3X reduction in cost without sacrificing performance.

The global recession serves as a painful reminder that we must always be conscious of our costs. The next decade for the semiconductor industry will again be an age of change—but this time for test. As the semiconductor industry looks to emerge from the global recession this year, remember to watch your test costs as you increase production capacity and augment lab capabilities. Keep an eye out for the latest PC-based technologies to help you lower your cost of test, and stay ahead of your competition in the future.

TAGS: Mobile Intel
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