In the last decade, the consensus within the test industry has been that a fundamental change is needed and that tester vendors should rethink and redesign the present-day test platform. According to the 2003 International Technology Roadmap for Semiconductors (ITRS),¹ without re-engineering, projected tester costs could increase beyond any acceptable level.

Further compounding these rising cost issues are the problems posed by today's specialized tester architectures. Incompatibilities force creation of specialized hardware and software for each tester that cannot be used with other testers. This also restricts the development of third-party solutions, which cannot be ported to different platforms without re-engineering.

To address this issue, in 2001, a group of companies formed the Semiconductor Test Consortium (STC) to define a configurable, modularized tester architecture. Since its formation, the STC has developed and released a set of specifications for the Open Semiconductor Test Architecture, or OPENSTAR®. The basic precept of this effort is that by working together, ATE and instrumentation suppliers can build an open-platform test system from interchangeable, multi-sourced, subsystem-level parts. Such an open system would cost less to purchase, installation, maintenance and upgrade than systems based on proprietary architectures. In addition, the availability of compatible, multi-sourced subsystem-level components and associated software will allow IC manufacturers to more accurately tailor system performance and cost to their needs than could using ATE systems based on proprietary architectures.

The OPENSTAR specifications achieve these goals by:

• Specifying in detail system, software, module-connection bus and mechanical architectures for ATE systems and their major components
• Providing ways to simplify the integration into ATE systems of hardware that conforms to such open standards.

The open, modular, reconfigurable, multi-site tester architecture focuses on using third-party modules and test instruments, while the hardware and software framework consists of standard interfaces. OPENSTAR-based test systems can thus incorporate modules from different vendors in a plug-and-play manner to achieve capabilities that match the requirements of each device under test (DUT).

Advantest - Driving Toward Open Standards

A charter member of the STC, Advantest is the first ATE company to implement OPENSTAR in a product. Having established, over its 50-year history, a noteworthy track record of helping customers turn technological innovations into practical, market-ready products, Advantest is uniquely experienced in opening new markets. In 2004, the company secured the number one position in ATE - a feat attributable to the underlying customer focus that drives all its development efforts. Advantest's spirit of innovation in all facets of ATE Ð memory, where it has long held the predominant market share; logic/system-on-chip (SoC); and radio-frequency (RF) test; as well as application-specific testers, interconnect products and handlers (a market it also leads) - is directly tied to its concerted efforts to develop user-oriented test solutions and its commitment to cycle-proof investments in R&D.

The company's T2000 SoC test platform (Figure 1) has been certified by the STC as being compliant with the OPENSTAR specifications.

In addition to supporting high-performance devices requiring multi-GHz data rates and RF test capabilities, the platform enables testing of cost-sensitive devices, such as microcontrollers using a low-cost configuration. With many configuration options for testing devices with different capabilities, the platform ensures users' ability to custom-build systems that meet their particular needs. Finally, the T2000's flexibility and modularized architecture allow IC manufacturers to quickly and economically upgrade or modify existing systems to accommodate changing product mixes and performance requirements.

Consistent with the OPENSTAR standard, the T2000 is designed to satisfy a range of test requirements through its ability to combine multiple test modules on a single platform, including 250-MHz digital modules, low- and high-current device-power-supply modules, and synchronization modules (for multiple time-domain and asynchronous functional test). The platform can thus accommodate multiple testing scenarios, including high-speed device test, at-speed test of sophisticated devices, design for test (DFT) to reduce test cost, and engineering test conducted in laboratory settings. All modules support high-speed data transfer via the OPENSTAR bus and high-speed test-condition loading. The T2000 mainframe hosts a dual computing architecture that incorporates both system and site controllers and enables truly independent, concurrent testing of multiple devices under test (DUTs).

A key feature of this new platform is its ability to deliver true hardware and software interoperability. The platform's software (Figure 2) is a distributed-object environment that runs under a Microsoft Windows operating system, providing a common ground for instrumentation and ATE companies to jointly adopt and support a variety of industry-standard test approaches.

The system and site controllers host system software components to support multi-site, multi-device testing. The overall software system is modular, drawing upon module-control software and a backplane-communication library. The modules include digital, device power-supply (DPS), arbitrary-waveform generator (AWG), digitizer and others as illustrated in the overall architecture (Figure 3).

An open-backplane-communication library, accessed via a C++ language-based test program and a graphical user interface (GUI) test-programming layer above C++ provides a generalized user interface for the test system. The primary language for test-program development is the OPENSTAR¨ Test Programming Language (OTPL), specified by the STC.

By eliminating fixed tester configurations, the T2000 embraces the following four key guidelines that form the basis for keeping test-equipment costs under control:

1. Modularization - Modular systems give users the flexibility to purchase and use options suitable for the product under test. Because there is no need to purchase unnecessary modules, the total equipment cost is automatically controlled.
2. Reconfigurability - Test-system reconfigurability is essential for an SoC-test platform. As needs change, users can reconfigure the test resources and continue to use the basic framework. Additional modules can be purchased and plugged in to reconfigure the test system for particular products. Avoiding the need for a new platform restrains test-equipment cost.
3. Parallel test - Parallel test improves the throughput and productivity of the equipment. As a rule of thumb, tester throughput increases by a factor of 1.6 to 1.8 in dual-DUT testing and 2.8 to 3.6 in quad-DUT testing. Higher throughput leads to lower overall test costs.
4. Employing third-party system components - The use of third-party hardware and software permits adoption of best-in-class solutions and creates competition that, over time, lowers test cost.

The T2000 platform not only simplifies test-system operation and use, but also provides a control mechanism for the test environment. Its open architecture encourages third parties to develop hardware and software modules that are plug-and-play compatible with the platform and can be reused with no major rework. Because the modules are replaceable, test managers can reconfigure a test site to achieve optimal DUT testing. This approach reduces engineering effort, enabling faster turn-around and significantly reducing test cost. Advantest is proud to be leading this charge in the ATE realm, leveraging its five decades of expertise to help ensure a better future for the semiconductor test industry. OPENSTAR is a registered trademark of the Semiconductor Test Consortium.

References

1. 2003 ITRS, released by SEMATECH in November 2003.