Patent ID: 6642725
Filing Date: 2003-11-04
Classification: G01R,G11C

Abstract:
A method of irradiating a synchronized dynamic random access memory (SDRAM) by a test device, wherein a status of the SDRAM after a radiation test is determined and calculated, the steps of the method comprising:performing a self-test on the test device after starting; waiting for a â€˜startâ€™ signal from an irradiation controller, the irradiation controller continuously producing periodic radiation, wherein each cycle of the periodic radiation includes on/off regions; checking whether the SDRAM is in an off region, wherein no radiation is radiated on the SDRAM, and a test pattern is written from the test device to the SDRAM; calculating readings obtained from the SDRAM, and obtaining a difference of the readings; checking whether the SDRAM is in an on region, wherein radiation is radiated on the SDRAM, and checking if there is an abnormal current present in the SDRAM, wherein: if there is an abnormal current present in the SDRAM, the test device goes back to the self-test step; if there is no abnormal current present in the SDRAM, checking whether the SDRAM is in an off region; ensuring the SDRAM is in the off region, wherein no radiation is radiated on the SDRAM, and a test pattern is written from the test device to the SDRAM; calculating the readings which are obtained from the SDRAM before and after the test, and obtaining a difference of these readings; checking whether a â€˜stopâ€™ signal is transmitted from the irradiation controller; and when the irradiation controller does not send out a â€˜stopâ€™ signal, returning to the step of writing a test pattern from the test device to the SDRAM, and calculating the readings which are obtained from the SDRAM before and after the test, and obtaining a difference of these readings.