Design And Implementation Of Automatic Calibration System For Hybrid Integrated Circuit Tester

With the development of integrated circuit(IC)industry,the demand of automatic test equipment(ATE)market for IC tester is increasing.As a kind of professional test equipment,the calibration technology of IC tester also needs to be developed.There are many kinds of test parameters of IC tester,which need to be calibrated regularly to ensure that the parameters can meet the test requirements.The automatic calibration system of hybrid integrated circuit tester developed in this paper provides 512 digital test channels,32 analog test channels and 8 power supply test channels.Through the cooperation of hardware control and neural network algorithm,the automatic calibration of hybrid integrated circuit tester is completed.This paper makes an in-depth research from the following four aspects:1.The method of parameter measurement and calibration is designed according to the characteristics of parameters.The parameters to be calibrated include 12 kinds of DC parameters and 4 kinds of AC parameters.In addition to the synchronization between digital channels and the parameter calibration of device power supply module(DPS)under test,the calibration of other parameters adopts the mode of "output calibration first,then input calibration",that is,the external measuring instrument is used to calibrate the output signal of the test channel first,and then the output signal of the test channel that has been calibrated is used to calibrate the input signal of the channel.2.The hardware system is designed according to the calibration scheme.Hardware system mainly includes the design of calibration board structure and interface,relay array and its control circuit,digital channel synchronous calibration circuit and local communication bus.As the core part of the whole hardware system,the calibration board can not only switch any relay to meet the measurement requirements of input and output signals of the tester,but also process the measured data online through ARM to realize the prediction of calibration coefficient.3.Automatic calibration process is designed for hybrid IC tester.In order to make the calibration system have the characteristics of high speed and high accuracy,this paper needs to weigh the calibration speed and measurement accuracy,and reasonably design the automatic calibration process,including the overall calibration process,parameter calibration sequence and specific test channel calibration sequence.4.The IC calibration technology based on radial basis function(RBF)neural network algorithm is studied and its engineering application is realized.By comparing the different performance of back propagation(BP)and RBF neural network in the test and verification phase through MATLAB simulation,the RBF algorithm is applied to the automatic calibration system of hybrid IC tester.The engineering application of RBF algorithm is described in detail,including the implementation process of RBF algorithm,data management and operation steps of calibration system software.The automatic calibration system is applied to the hybrid integrated circuit tester,and the test results meet the index requirements,which shows that the automatic calibration system of the hybrid integrated circuit tester developed in this project has feasibility and application value.