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Building Multisite MEMS Microphone Test Equipment Using NI PXI and LabVIEW

陳建銘 Jemmy Chen, 思衛科技股份有限公司 (Jetek Technology )

"The 32-site MEMS microphone test system built using NI PXI modular instrumentation with the LabVIEW FPGA Module allows real-time computation and production testing to be carried out concurrently. Compared to fixed function traditional automated test equipment, the speed of testing digital microphones increased by about 20X because of the modular hardware and open software. This reduces overall equipment costs and offers excellent system expansion flexibility."

- 陳建銘 Jemmy Chen, 思衛科技股份有限公司 (Jetek Technology )

The Challenge:

Providing testing companies with more test channels, reduced test time, and improved performance so equipment manufacturers can meet the industrial demand for microelectromechanical sensors (MEMS).

The Solution:

We used NI PXI hardware with the NI LabVIEW FPGA Module to develop the 32-site MEMS microphone test equipment. This architecture combined PXI with LabVIEW FPGA to help us design the required solution, create the prototype, and complete the hardware control system in a short time.

 

According to Laurent Robin, a MEMS equipment and technology analyst from the French research company Yole Development, MEMS will see a compound annual growth rate of 13 percent over the next five years in response to changes in consumer applications. With such a high growth rate, demand for MEMS microphone components in mobile devices is increasing by a significant margin. However, during production testing, any vibration or noise affects the test results of the MEMS microphone components. Hence, the test equipment speed and mounting and moving the device under test cannot be excessively fast. There is a demand for multisite MEMS test equipment o increase production capacity, meet the customer expectations of increasing testing speed, control costs, and maintain efficiency.

 

 

In light of these requirements, we discussed with and worked with our customers to increase the number of sites for the test equipment. We concluded that we could reduce the overall testing time, and thereby increase the test volume within the same period of time, if we expanded the number of sites from 4 to 32. Accounting for the replacement rate of semiconductor equipment and the customers’ cost considerations, if we continued using a traditional test equipment architecture, expansion alone would pose a problem. We decided to use the NI PXI platform, which is a standard in the industry. In the beginning, semiconductor companies were skeptical of us using the NI PXI platform to build test equipment, especially because production lines need to remain open 24 hours a day and there is no margin for error. We began by plugging in the PXI system to the side of the test equipment so customers could become familiar with it and slowly build up their understanding and approval of PXI. If the customers’ labs are already using the PXI system, the time for correlation analysis from the lab to the production line will also be reduced. This can also improve the overall time to market for customers.

 

 

In this instance with the 32-site MEMS microphone test equipment, we used the NI PXI hardware with the NI LabVIEW FPGA Module to develop the test system. This architecture combines PXI with LabVIEW FPGA to help us design the required solution, create the prototype, and complete the hardware control system in a short time. PXI is a modular platform equipped with excellent test functions, so customers only need to add modules to expand the system’s functionality, instead of changing all of their equipment like they would need to do with a traditional automated test system. Customers have cut equipment costs by taking advantage of characteristics such as low cost, high flexibility, and excellent performance.

 

In the past, to capture the test signal, we had to wait for a data dump before carrying out a calculation on the PC, which is normally time consuming. We used the LabVIEW FPGA Module for arithmetic processing to carry out more customized and complex testing, since the 32-site system requires higher speed and performance. Once we capture the data, we can carry out point-by-point, real-time processing using the FPGA. Since the FPGA for PXI has multiple channels, it can concurrently process multiple records and increase the testing speed of the entire test system by roughly 20X.

 

 

We completed the 32-site test system using NI PXI and the LabVIEW FPGA Module and transferred the system to Hon Technologies, a specialized manufacturer of semiconductor packaging and testing equipment, for final assembly and testing. Hon Technologies completed all the detailed calibration, and customers are now using the 32-site MEMS microphone test equipment.

 

From the planning stage to the actual completion of the entire system architecture, NI offered complete software and hardware platforms and made every effort to provide technical and peripheral support. We were impressed with NI’s focused commitment to ensuring the success of its customers. We also believe that NI PXI and LabVIEW FPGA can respond to the MEMS multisite trend, which in turn will help us develop customized MEMS testing platforms for customers and provide high-efficiency, low-cost solutions.

 

Author Information:

陳建銘 Jemmy Chen
思衛科技股份有限公司 (Jetek Technology )
Taiwan
Jemmy_Chen@jetek.com.tw

Figure 1. We used the LabVIEW FPGA Module and NI PXI modules to complete the 32-site MEMS microphone test equipment.
Figure 2. We took advantage of the NI PXI platform and LabVIEW FPGA in the 32-site MEMS microphone test equipment to develop the test system.
Figure 3. The engineer can use the LabVIEW graphical interface to design the required solution and create the prototype more quickly to complete the hardware control system.
Figure 4. The team used the NI PXI platform and the LabVIEW FPGA Module to build a professionally customized multisite MEMS microphone test system for customers.