Create stable and efficient automatic testing equipment from multiple dimensions

Create stable and efficient automatic test equipment from multiple dimensions to meet the opportunities and challenges of the integrated circuit integration era

The maturity of new technologies such as 5G, artificial intelligence, and new energy has driven various industries to accelerate the implementation of digital transformation, thereby continuing to promote the steady growth of the global semiconductor industry. According to the IC Insights semiconductor industry report, global semiconductor sales are expected to increase by another 11% in 2022, reaching a new record of US$680.6 billion. The continued prosperity of the semiconductor industry has also led to a surge in the market size of semiconductor automatic test equipment (ATE), which is expected to reach US$7.2 billion in 2028.

Cai Zhenyu, Director of Industrial Market, ADI China

As a key link in the semiconductor industry, ATE runs through the entire process of semiconductor design, manufacturing and packaging, and is crucial to monitoring product yield and judging product quality. However, in the face of today's ever-changing IC industry, ATE testing is also facing various new challenges. " Chips have entered the 3nm era, and there are more and more functions on a chip, and the chip process is becoming more and more complex. This not only means that the complexity of testing has increased exponentially , but also makes the chip yield more dependent on the advanced functions of testing. How to quickly and efficiently complete the development of a new generation of ATE solutions to meet the market's demand for large-scale shipments and various types of semiconductor testing has become a new problem that the industry urgently needs to solve." Cai Zhenyu, director of industrial marketing at ADI China, said. As a global leading high-performance semiconductor company that has been deeply involved in the semiconductor field for decades, ADI has more than 20 years of experience in the ATE industry, has deep technical accumulation, and has launched a number of solutions that have been widely welcomed by the industry.

Semiconductor industry chain "connects the upper and lower", automated testing equipment is critical

In the semiconductor industry chain, the life cycle of a chip begins with the analysis of market demand, followed by product definition, design and manufacturing, and delivery to end consumers after packaging. It needs to undergo multiple tests in the entire process. "Among them, ATE testing belongs to the manufacturing link and is a crucial link in the transition from R&D to mass production. The higher the end and more complex the function of the chip, the higher its dependence on testing. At the same time, the various advanced functions of testing equipment are becoming increasingly important for semiconductor manufacturers such as 5G, IoT and cloud computing." Cai Zhenyu emphasized.

According to the application classification of semiconductor test systems, the main subdivisions of ATE applications are memory, SoC, analog, digital, discrete devices and RF testers. Regardless of the application, ATE usually needs to complete chip functional testing, DC parameter testing and AC functional testing. The principle is to apply input signals to the chip, collect the output signals of the tested chip and compare them with the expected values, judge the effectiveness of the chip's functions and performance under different working conditions, and ensure that in the corresponding chip manufacturing, the product meets customer design, manufacturing requirements and market demand.

ATE System

Since the quality of the test solution directly affects the yield and test cost, data shows that the impact of chip defect-related failures on costs ranges from tens of dollars at the IC level to hundreds of dollars at the module level, and even thousands of dollars at the application end level. "At present, the chip development cycle has been shortened, and the success rate of tape-out is very high. Any failure is unbearable for enterprises. Therefore, sufficient verification and testing are required during the chip design and development process." Cai Zhenyu pointed out.

Starting from several key test dimensions, we create a stable and efficient ATE product solution

As Moore's Law continues to develop, the complexity of processes and applications continues to increase. If the semiconductor industry wants to make good products, it needs to pay more attention to "testing first". Semiconductor technology is still evolving, the sophistication of manufacturing processes and the complexity of chip internal structures are constantly increasing, a chip carries more and more functions, the integration of transistors on the chip is getting higher and higher, and the product iteration speed is getting faster and faster. Even many highly complex chips such as AI, GPU and AP require annual iterations, which makes the complexity of testing and verification increase sharply, and the testing time and cost also increase accordingly.

"The key to market competition in semiconductor testers lies in the breadth of testing, test accuracy, test speed, and the scalability of the tester. The wider the test coverage of the tester and the more items that can be tested, the more popular it is with customers," said Cai Zhenyu. Important indicators of test accuracy include the accuracy of test current, voltage, capacitance, time and other parameters. Advanced equipment can generally achieve an accuracy of picoamperes (pA) in current measurement, microvolts (μV) in voltage measurement, 0.01 picofarads (pF) in capacitance measurement, and hundreds of picoseconds (pS) in time measurement. The scalability of the tester is mainly reflected in whether the test function, channels and number of workstations can be flexibly increased according to needs.

Faced with these challenges, test equipment developers are in urgent need of stable ATE solutions, and also expect high-quality test coverage, the ability to support more channels, and the ability to test as many units as possible within a unit of time. ADI has launched ATE ASSP (Application Specific Standard Products), which covers advanced integrated pin electronics (PE), device power supplies (DPS), and parameter measurement units (PMU) and other products, further helping customers improve the performance of ATE machines and reduce their costs with advantages such as low power consumption and high integration.

Pin electronics, device power supplies and parameter measurement unit product function and performance positioning

"For general ATE applications, the signal chains are relatively similar. We have integrated some functions together to reduce the design difficulty for customers. This is one of the main reasons why ADI makes ASSP. In addition, ATE testing needs to support multiple channels. Multi-channel parallel testing increases the complexity of testing, and better performance chips are needed to meet the needs of customer testers." Cai Zhenyu explained ADI's considerations for ASSP solutions in the ATE field. "ADI's ASSP integrates many functions into one chip, which can further help customers reduce the cost of testers and increase measurement density. The multi-mode packaging we use can also further help customers reduce costs and power consumption compared to discrete device solutions."

Basic block diagram of the signal chain for ATE digital measurements

Among them, PE is used to generate signals to stimulate the object under test in order to obtain feedback from the object under test, so the PE chip is required to have higher precision. At the same time, integration is also a key requirement for the solution, such as integrated pin electronics/pin drivers to provide key test application solutions in a single package, including digital drive and comparison functions, active loads, and per-pin parameter measurement units , which are controlled by level-setting DACs. "For domestic ATE market applications, ADATE318 and ADATE320 are currently widely used, with data rates ranging from 600MHz to 1.6GHz. Among them, ADATE318 is more suitable for digital chips, memories, mixed signal testing, etc., while the data rate of ADATE320 will be higher, which is more suitable for high-speed chip testing." Cai Zhenyu added.

ADATE3xx Block Diagram and Parameters

In response to the measurement needs of higher-speed chips, ADATE334 provides key test applications in a dual-channel single package. The dedicated 16-bit digital-to-analog converter (DAC) with integrated calibration registers can provide all the DC levels required for the device to work, and can support up to 2.3GHz~4.6Gbps with high precision and low power consumption. "In the future, ADI's PE chips will continue to develop in two directions, namely, the research and development of higher-speed products and more channel density integrated products." Cai Zhenyu described the key evolution roadmap of ADI PE.

PMU and DPS products are used to provide flexible voltage and current source/measurement functions to meet the needs of various cost-sensitive test applications. The role of the PMU is to drive current into the device to measure voltage or to add voltage to the device to measure the resulting current. Its integration, measurement accuracy and number of channels are several important dimensions that are usually evaluated. ADI's AD5522 is a high-performance, highly integrated parameter measurement unit that includes four independent channels. Each single-pin parameter measurement unit (PPMU) channel includes five 16-bit voltage output DACs that can set programmable input levels for the drive voltage input, clamp input, and comparator input (high and low).

AD5522 Device Block Diagram

DPS is used to provide programmable power supply for the DUT, usually with high current and high voltage. For example, the high-performance, highly integrated device power supply AD5560 provides programmable drive voltage and measurement range. The product includes the required DAC level to set the programmable input of the drive amplifier, as well as clamp and comparator circuits, and on-chip integrated offset and gain correction functions for DAC functions.