Research on the Traceability Technology of ate qua

Research on the quantity Traceability Technology of digital integrated circuit test equipment (ATE)

background

with the rapid development of the technology industry, modern large-scale multi parameter automatic measurement instruments and equipment are more and more widely used. The problem of quantity traceability makes the traditional measurement methods and theories face new challenges. The measurement and calibration of digital integrated circuit test equipment (hereinafter referred to as ate) is an example: this kind of equipment is relatively complex and inconvenient to handle, the system operation depends on software control, and the test procedures of different types of ate are often incompatible. At present, the state has not promulgated the verification regulations or calibration specifications of such equipment, nor has it carried out the metrological calibration of integrated circuit test equipment

the manufacturers of ate equipment abroad attach great importance to its calibration and traceability. For example, many integrated circuit test systems introduced in China in recent years have special self calibration boards. Manufacturers require users to regularly send their self calibration modules back to the factory for calibration traceability. For many reasons, it is often difficult for domestic users to use this method to ensure the traceability of ate parameters. With the wide implementation of ISO9000 in the world, the requirements for calibration and traceability of measuring equipment are more clear than before. IC test equipment is naturally the key equipment that needs to trace the value of quantity. It is an important problem for us to solve the value traceability of this kind of equipment as soon as possible

based on the understanding of IC test system and the analysis of its characteristic parameters We believe that adopting the principle of measurement assurance programs (hereinafter referred to as map) may be a better way to solve the large-scale value traceability problem such as ate

second, icmap and traditional measurement value transmission

1. Measurement value transmission and traceability

measurement value transmission is to measure the measurement unit reproduced in the national measurement standard through the verification or calibration of the measurement instrument, which does not affect the accuracy value transmitted to the working measurement instrument through the measurement standards of all levels, so as to ensure the accuracy and consistency of the measured object measurement value

calibration is the process of comparing the measured object (unknown device) with a standard equivalent to or better than it. Take the standard as the basis for reference, and think that the standard is more correct between the two. Through calibration, we can know how much the unknown device differs from the standard

quantity traceability: traceability is a continuous comparison chain from the measurement to the national legal standard Users are free to find superior standards that meet the requirements according to the actual situation

2. The traditional value transmission method

regularly send the instrument to the measurement department with a higher level measurement standard according to the measurement cycle specified in the verification regulation, and professionals will verify the performance of the instrument; Only for the verification of instruments and equipment, ate often does not consider the quality of its test results

3. At present, there are several ways to control integrated circuit test equipment in China. The ISO9001 standard requires that the test value of the equipment be traced to SI units

in order to meet the requirements of this clause, people

have carried out various explorations in the traceability of ate equipment. There are roughly the following modes:

(1) sample comparison test: select several devices to test on multiple ate. If the test conditions are clearly specified and the devices and test parameters are properly selected, there will be a certain degree of comparability between the systems. But it is not the true sense of traceability

(2) traditional transmission mode: a calibration device is composed of multiple standard instruments. For different ate, we need to develop different measurement software and make special adapters. The system can be traced to the source, but the development cost is large

(3) self calibration module traceability: users calibrate with the self calibration module brought by the system. And regularly send the self calibration module to the original manufacturer for calibration to ensure the accuracy of calibration. Since this self calibration module is provided by the manufacturer, the design must consider the characteristics of the product. However, due to various reasons, the vast majority of domestic units cannot regularly send the calibration module to the manufacturer for calibration according to the regulations of Guangjia. In this way, there is no waste foam granulator, and enterprises above the manufacturing industry pay 1398.77 billion yuan to form an uninterrupted traceability chain. When some benchmarks on the calibration board fail, users may not find problems in time

(4) icmap scheme: establish a corresponding mathematical model for the measurement process of mathematical integrated circuits. By regularly testing the verification standards, accumulating data, and processing these data with statistical methods according to the established mathematical model, the process parameters are obtained. Through the inspection of process parameters, we can confirm whether the measurement results are under control. At the same time, the high efficiency Laboratory of the center uses measurement standards and transmission standards to transmit the quantity value of participants. The project of this plan is to examine the whole process of measurement, such as measuring devices, personnel quality, environmental conditions, experimental methods, etc. It is characterized by convenience and flexibility, and meets the requirements of process control and verification in current IS09000 and ISO17025 standards The environment close to the user's actual test can reflect the situation of the calibrated object more realistically. Good versatility, suitable for the calibration of more general ate

4. Specific implementation of integrated circuit parameter measurement assurance scheme (icmap)

the specific method of integrated circuit parameter measurement assurance scheme is to use a set of stable, well packaged and transportable delivery standards as unknown samples. When the user needs it, it will be sent to the user's laboratory site. After the temperature is balanced, the site staff will measure the specified parameters according to the normal operating procedures. The measured "transfer standard" is sent back to the icmap central laboratory (such as CESI) for re measurement, and then the data in CESI and the data measured in the laboratory are statistically analyzed. CESI gives a test report, which states the deviation between the laboratory's measurement results and CESI and the total measurement uncertainty

in order to keep the measurement process of the laboratories participating in this activity under continuous statistical control, within the time interval after the "transfer standard" measurement, the "check standard" with good stability in the laboratory must also be used, and the measurement must be repeated frequently to check whether the random change is within the specified qualified value, so as to ensure that the measurement process is under continuous control

the following figure is: implementation block diagram of digital integrated circuit measurement assurance scheme

three traceability of digital integrated circuit parameters