What equipment is needed for chip testing? What test method is used?

In recent years, the demand of semiconductor equipment market in Chinese Mainland has grown rapidly. In this context, the high-precision detection equipment that must be used for chip wafer detection also has an increasingly broad market. Due to each functional component having its own testing requirements, design engineers must make testing plans in the early stages of design. This article will organize and share with you about chip testing equipment and methods.

What equipment is required for chip testing

Chip testing mainly uses detection equipment such as chip testing machines, probe stations, sorting machines, etc.

Chip testing machine

A testing machine is a specialized device used to test the functionality and performance of a chip. During testing, the testing machine applies an input signal to the chip under test, compares the output signal with the expected value, and determines the electrical performance of the chip and the effectiveness of product functionality. In the CP and FT detection stages, the testing machine transmits the results to the probe station and sorting machine respectively. After receiving the test results, the probe station will perform inkjet operation to mark the chips with defects on the wafer; When the sorter receives the results from the testing machine, it will round and classify the chips.

Probe station

The probe station is used in the CP testing stage after wafer processing and before packaging process, responsible for the transportation and positioning of the wafer, so that the grains on the wafer come into contact with the probe one by one and are tested one by one. The workflow of the probe station is as follows: move the wafer under the wafer camera through the slide station, capture wafer images through the wafer camera to determine the wafer position, move the probe camera under the probe card, determine the probe head position, move the wafer under the probe card, and then achieve needle alignment through vertical movement of the slide station.

Sorter

Sorting equipment is applied in the FT testing stage after chip packaging, which is a post test equipment that provides chip screening and classification functions. The sorting machine is responsible for transporting the input chips to the testing module according to the system design's picking and placing method to complete circuit voltage testing. In this step, the sorting machine selects and classifies the circuit based on the test results.

Several Common Methods for Chip Function Testing

There are six commonly used methods for chip functional testing: board level testing, wafer CP testing, FT testing of packaged products, system level SLT testing, reliability testing, and a combination of multiple strategies.

Board level testing: mainly used for functional testing, using PCB boards and chips to build a "simulated" chip working environment, pulling out all the chip interfaces, detecting the chip's functions, or checking whether the chip can work normally in various harsh environments. The equipment that needs to be applied is mainly instruments and meters, and the main thing that needs to be produced is the EVB evaluation board.

System level SLT testing: Often used in functional testing, performance testing, and reliability testing, it often exists as a supplement to finished product FT testing. As the name suggests, testing is conducted in a system environment, where the chip is placed in its normal working environment to test its functionality. The disadvantage is that it can only cover a part of the functionality, with low coverage, so it is generally a supplementary means of FT.

Reliability testing: mainly aimed at applying various harsh environments to the chip, such as ESD static electricity, which simulates human or industrial bodies to apply instantaneous high voltage testing to the chip.

Finished product FT testing after packaging: commonly used in functional testing, performance testing, and reliability testing, to check whether the chip functions properly and whether there are defects generated during the packaging process. It also helps to detect whether the chip can still work after being subjected to fire, snow, and lightning in reliability testing.

Wafer CP testing：commonly used in functional and performance testing to understand whether the chip is functioning properly and to screen out faulty chips in the chip wafer.

Multiple strategies simultaneously：Based on our testing needs, we will adopt a combination of multiple testing methods for testing.

Repeated testing and testing are required at every stage of semiconductor design, manufacturing, and packaging to ensure product quality and develop devices that meet system requirements. The cost of defects related failures is high, ranging from tens of dollars at the IC level to hundreds of dollars at the module level, and even thousands of dollars at the application level. Therefore, testing equipment plays an irreplaceable important role from design verification to the entire semiconductor manufacturing process.

Shenzhen Tec Optoelectronic Technology Co., Ltd. was established in 2012, specializing in the research and production of IC probe benches, chip testing machines, semiconductor testing tape machines, and semiconductor testing instruments. After years of development, the company has become a national high-tech enterprise integrating design, research and development, production, sales, and service. In 2022, the company was named a "specialized, refined, unique, and new" enterprise in Shenzhen. The company's headquarters and production base are located in Shenzhen, and a branch has been established in Hong Kong, with products selling well worldwide. The company not only has the ability to develop software and instruments, but also breaks through the domestic technology gap of SMU (constant current source meter) and ESD (human electrostatic module) technology. The chip testing equipment has been applied in the semiconductor industry for many years and has been fully recognized by industry customers, becoming a scarce resource and a new favorite in the industry in China. Tech Optoelectronics will continuously surpass itself, innovate and lead the development of the semiconductor testing industry, and provide customers with better one-stop overall solutions.