The 32-bit MPC5675 chip designed and manufactured by NXP Semiconductor Company is widely used in automotive power steering system, advanced driving assistant system and other equipment related to automotive safety, which provides a strong guarantee for automotive safety. The high integration of chip circuits brings more challenges to chip testing. Aiming at the problems of MPC5675 chip in the process of temperature measurement module test and digital-to-analog conversion test, the methods of comparing temperature measurement value with room temperature reference value and dynamic contact resistance test are adopted respectively to optimize the test procedure and improve the chip’s yield. The test scheme can be used in the test of MPC5675 series chips. In order to meet the rapid expansion of the global automotive market and the increasing trend of automotive electronization, Enzhipu Semiconductor Company has developed a series of automotive electronic systems, which include microcontrollers, analog devices and sensors. The system is suitable for power transmission system, chassis control system, safety system and automotive internal communication system. And the application of automotive electronic system such as body control system.
The scale of integrated circuit chip (IC) circuit increases, but the package volume decreases and the function increases, which brings challenges to chip testing and will promote the rapid development of the corresponding chip testing technology [1-2]. This paper deals with MPC5675 series chips designed and manufactured by NXP Semiconductor Company.
The chip is a 32-bit embedded control system based on Power Architecture. It can be used in advanced driving assistant systems equipped with radar, CMOS imaging, lidar and ultrasonic sensors, multi-three-phase motor control applications in automobiles and automobiles. Hybrid Electric Vehicle (HEV) and applications requiring high safety integration [3-4]. The chip MPC56675 is packaged with MAPBGA technology and has 257 pins.
Its appearance size is 14 mm*14 mm. In addition to the above 257-pin MPC5675 chip, we also produce 473-pin MPC5675 chip.
According to the fabrication process, wafer is tested by probe, followed by comprehensive functional testing, and finally the quality and safety testing is carried out to improve the quality of the chip. As a supplier of customer IC, we design functional chips and provide comprehensive, complete and high-quality chip testing to ensure the functional perfection and stability of the chip.
According to the function and principle of chip design, the strategy and method of testing chip are designed to verify the quality and reliability of the chip.
Through careful study of MPC5675 function description and pin function, a complete test program is designed. MPC5675 chip testing process includes DC parameter testing, memory testing, digital function testing, temperature testing and analog function testing. The design program is applied to the test machine to test the chip comprehensively, analyze and study the data, summarize and analyze the problems in collaborative design and process, improve the stability and reliability of the chip, and ultimately improve the yield of the chip [5-6].
This paper studies and explores the optimization of digital-to-analog conversion test in temperature measurement module test and analog function test. To be used in automobile power steering system, advanced driving assistant system and other equipment related to automobile safety, MPC5675 must have good ability to withstand high temperature, low temperature and room temperature.
The highest temperature range of automotive grade is – 40 C to 140 C. Therefore, each chip is tested separately at low temperature limit – 40 C, high temperature limit 145 C and room temperature 25 C. The test steps are shown in Figure 1. The high cost of automotive semiconductor chip testing is due to the ultimate need to ensure zero defects, so as to ensure driving safety.
In the process of temperature measurement module test, digital-to-analog conversion test and digital test, according to the problems encountered in the test, thermostatic element the program is revised to improve the chip quality rate. In the temperature measurement module test, there is a problem that the test results are offset due to the instability of ambient temperature, and good products are mistaken for inferior products. In analog-to-digital conversion testing, the results of digital output will be affected by the change of contact resistance on the test path.
In order to reduce the influence of contact resistance, the function of dynamic contact resistance test is introduced. When the port is set as output, the method of measuring voltage by adding current and calculating resistance is compared with the experiential value. If the calculated resistance value exceeds the limit, the self-cleaning function is started to remove the foreign impurities in the contact position and reduce the additional connection. Contact resistance; or use dynamic calculation method to subtract the measurement value drift caused by contact resistance, improve the accuracy and accuracy of the test. NXP Semiconductor designs and manufactures MPC5675 chips which are compatible with 32-bit CPU core and Power Architecture. It is mainly used in automotive power steering system, advanced driving assistant system and other equipment related to automotive safety. According to the problems in functional testing, this paper optimizes the testing procedures to improve the rate of good products. In the test of temperature measurement module, the method of comparing temperature measurement value with room temperature reference value is adopted; in the test of analog-to-digital conversion, the method of dynamic contact resistance is adopted. Based on the above method, the test program is optimized to improve the chip quality rate, and the effect is remarkable.