Method for analyzing stability of semiconductor of semiconductor device tester

PURPOSE: A method for analyzing stability of a semiconductor device tester is provided to verify the correct operation and functional stability of a tester for semiconductor devices by comparing the measured electrical characteristics of a standard device with reference electrical characteristics data for that device. CONSTITUTION: A test engineer reads a mode of selected operation, and if in the standard-device-creation mode, the type number and serial number of a candidate standard device loaded in the tester are read. Then, it is determined whether a standard device having identical type and serial numbers is available, and if such standard device is available, it is determined whether to replace such standard device. Next, if such standard device is not available, or if it is determined to replace such standard device, the candidate device is repeatedly tested a predefined number of times to measure during each test a predefined set of test items comprising electrical characteristics of the candidate device. Then, the mean values and standard deviations of every test item in the sets are calculated. Next, it is determined whether the candidate device is suitable for use as a standard device, based on whether the calculated values and standard deviations are within predetermined distribution ranges. If in the tester-check mode, the type number and serial number of a standard device loaded in the tester are read. Then, reference data comprising a set of previously measured electrical characteristics of the standard device are fetched, and the standard device with the tester a predefined number of times is repeatedly tested to measure during each test a set of electrical characteristics of the standard device corresponding to the previously measured electrical characteristics of the standard device fetched. Then, a mean value X of every electrical characteristic measured in the sets is calculated, and the test data are compared with the reference data to determine whether the tester is functionally stable.