Big Data and ATE Drive Component Quality

An effective semiconductor test strategy extends from individual test cells comprising ATE systems, wafer probers, test contactors, and handlers up to supply-chain-wide software tools that can analyze the terabytes of data that semiconductor test operations produce. So far this year, vendors have debuted innovations across the test cell to enterprise software gamut to ensure IC quality and customer satisfaction.

Enterprise Software

In EE-Evaluation Engineering’s April Executive Insight column, David Park, vice president of worldwide marketing for OptimalTest, described his company’s three-pillared approach for handling big data: gather data from global test operations, offer tools that can mine the data, and assign field engineers who can solve specific customer needs.¹ A key goal is to reduce parts subject to return-material authorization (RMA) from various sources (Figure 1).

Figure 1. Causes of Return-Material Authorizations

Source: OptimalTest

Since that article went to press, OptimalTest introduced Release 5.5 of its OptimalEnterprise solution, which is architected on a new data platform called Sequoia that enables test and product engineers to customize their environment themselves based on their specific manufacturing requirements.

Park described Sequoia as “a flexible framework to take any data from any operation, manipulate it, analyze it, and translate it into action across your supply chain.” Customers, he said, can use Sequoia to customize and extend the capabilities of OptimalTest tools by incorporating data from external databases and manipulating and augmenting test data by creating virtual tests. Furthermore, they can extend OptimalTest products with their own algorithms.

In addition, he said, “Customers can establish quality indices by combining any manufacturing test data”—related, for example, to wafer geography, part-average-test rules, and equipment health. Finally, they can perform cross-operational analysis to identify and detect company-specific issues and trends by feeding physical and virtual test data from one operation to another.

Release 5.5 also incorporates new capabilities for outlier detection, automated ATE configuration, and enhanced part traceability.

Craig Nishizaki, senior director of ATE development at NVIDIA, described his company’s use of OptimalTest tools to implement yield monitoring and improvement and customer RMA analysis at the International Test Conference last September.² Speaking in March about the new OptimalEnterprise 5.5 release, he said, “OptimalTest’s outlier detection capabilities enable us to perform real-time drift screening in our manufacturing operations. The new data augmentation capabilities in Release 5.5 allow us to define actionable parameters based on the results of multiple test insertion steps. Using this cross-operational information, we can make very sophisticated real-time decisions in test operations that enable us to measurably improve our product quality. That benefits both NVIDIA and our customers.”³

Semiconductor Test Equipment

On the test-equipment front, companies including Advantest and Multitest have announced the development of new products or capabilities this year.

Advantest, for example, debuted a test solution for next-generation memory ICs that enables mobile applications and servers. The new T5503HS provides highly parallel testing capabilities and full compatibility with Advantest’s widely used T5503 test platform.

“Our new test system offers the optimal test solution for next-generation DDR4-SDRAMs and LPDDR4-SDRAMs,” said Masuhiro Yamada, executive vice president of memory test for Advantest. “The T5503HS delivers maximum efficiency while helping our customers to get the most from their capital investments.” The T5503HS reaches testing speeds of 4.5 Gb/s and can test up to 512 DDR4 SDRAM devices in parallel.

The company also introduced two new test modules for high-speed, cost-efficient testing of RF ICs used in cell phones and wireless LAN devices built to meet 802.11ac and LTE-Advanced mobile communications standards. Both the 32-port WLS32-A module and the 16-port WLS16-A module are fully compatible with Advantest’s T2000 platform. Each module offers a modulation bandwidth of 80 MHz combined with waveform generator software and modulation analysis software for 802.11ac and LTE-Advanced protocols.

“With these new modules, we are continuing to provide our customers with the versatile test solutions they need to address high-volume wireless communications markets with minimal investment,” said Dr. Toshiyuki Okayasu, executive officer and executive vice president, SoC Test Business Group at Advantest.

Advantest continues to develop the V93000 platform, which it acquired with its purchase of Verigy. In March, the company announced the Pin Scale Serial Link (PSSL) card for at-speed characterization and volume production of high-speed semiconductors. PSSL is capable of data rates up to 16 Gb/s.

Built on the V93000 Smart Scale’s universal pin architecture, PSSL can perform efficient multisite per-pin testing. Each pin on a PSSL card can run at its own data rate. All resources operate independently and concurrently. With these capabilities, the new card can test advanced ICs designed for infrastructure and network processing applications such as 10G/40G/100G Ethernet, PCI Express, or the proprietary 10G to 16G backplane SerDes technology, used throughout China’s LTE communications infrastructure.

“Testing today’s fastest IC interfaces with sufficient coverage requires an at-speed test solution that can deliver a low cost of test,” said Hans-Juergen Wagner, senior vice president, SoC Business Group at Advantest. “Our new PSSL card offers this needed speed and performance, extending Advantest’s leadership in high-speed ATE instrumentation.”

Also for the V93000, Advantest introduced its DPS128HV module, a high-density device power supply unit designed to handle a wide range of operating voltages for testing devices such as eFlash memory ICs. With the new module, Advantest’s V93000 test platform can be scaled from low-channel to high-channel configurations.

V93000 configurations equipped with the new module can test up to 1,024 independent sites in parallel, achieving multisite efficiency as high as 99.9%. The module’s operating range extends from -6 V to +15 V at 200 mA. Its 128 independent voltage/current resources offer four-wire Kelvin connections. To increase the supply current, multiple channels can be ganged. The unit can conduct voltage and current profiling as well as control its slew rates. It tests analog interfaces using an 18-bit digitizer and a 16-bit arbitrary waveform generator. “As the highest density instrument in the industry, our extended V93000 platform is generating great interest among manufacturers of eFlash memories, particularly in China,” said Wagner.

MEMS and Sensor Test

Multitest has been active on several fronts. LTX-Credence purchased Multitest along with Everett-Charles Technologies from Dover Corp. last year to extend its reach across the semiconductor test cell.⁴ Results were on display in March at SEMICON China, where Multitest and LTX-Credence demonstrated a full test cell setup dedicated to the test of mobile-device semiconductors. The test cell consisted of an LTX-Credence Diamondx ATE system, a Multitest MT2168 pick-and-place handler, a Multitest Mercury contactor, and a Multitest high-layer-count load board. The test-cell components were selected to support parallelism for efficient high-volume production test and scalability to support engineering and volume production needs and ensure shortest time to market. The cell could test highly integrated, fine-pitch, and small form-factor packages.

In addition, Multitest has been focusing on MEMS and sensors. In January, the company reported a clear trend to reduced package sizes—from MLF4 to MLF2—for humidity sensor applications. Multitest said its MEMS and sensor test concept is based on standard test handlers with MEMS- or sensor-specific modules added—in one case, a third-party conditioner was integrated into the test handler. Customers can change from one humidity sensor package to another by deploying a different conversion kit. When not used for sensor test, the test handler can be used for standard IC handling to maximize utilization and return on investment.

Andreas Ludwig, product manager at Multitest, said “We see this trend for package size not only at specific customers but also in the overall market. Driven by mobility and the Internet of Things with ever smaller and lighter end products, sensors need to comply with the package size requirements to be successful.” He added, “Achieving best cost of test by highest utilization will contribute to a competitive cost structure and ASP of the sensors.”

Multitest also announced that early this year it shipped its first fully integrated test cell for a pressure-sensor application consisting of handling systems, ATE, and contactors. The test cell consists of Multitest equipment as well as third-party equipment. The customer specified the overall test cell requirements in terms of test condition, yield, and output. The Multitest team then translated these requirements into a specification for each individual test-cell element with a focus on optimization of the overall functionalities, interactions, and interdependencies. The process was finalized with a mechanical and electrical quality check and a comprehensive buy-off, including correlation validation prior to the shipment.

Said Ludwig, “In this project, the customer had to handle a fast ramp with a very small team. So relying on the Multitest experience for sensor test and test-cell integration enabled his team to focus on their core tasks in production planning. This way, getting an integrated turnkey solution was a substantial success factor for the customer.”