IEC 60749-18 pdf download.Semiconductor devices – Mechanical and climatic test methods
This part of IEC 60749 provides a test procedure for defining requirements for testing packaged semiconductor integrated circuits and discrete semiconductor devices for ionizing radiation (total dose) effects from a cobalt-60 ( 60 Co) gamma ray source. This standard provides an accelerated annealing test for estimating low dose rate ionizing radiation effects on devices. This annealing test is important for low dose rate or certain other applications in which devices may exhibit significant time-dependent effects. This standard addresses only steady-state irradiations, and is not applicable to pulse type irradiations. It is intended for military- and space-related applications. This standard may produce severe degradation of the electrical properties of irradiated devices and thus should be considered a destructive test.
2 Terms and definitions
For the purposes of this part of IEC 60749, the following terms and definitions apply. 2.1 ionizing radiation effects changes in the electrical parameters of a device or integrated circuit resulting from radiation- induced charge NOTE These are also referred to as total dose effects. 2.2 in-flux test electrical measurements made on devices during irradiation exposure 2.3 non in-flux test electrical measurements made on devices at any time other than during irradiation 2.4 remote tests electrical measurements made on devices that are physically removed from the radiation location 2.5 time-dependent effects significant degradation in electrical parameters caused by the growth or annealing or both of radiation-induced trapped charge after irradiation NOTE Similar effects also take place during irradiation. 2.6 accelerated annealing test procedure utilizing elevated temperature to accelerate time-dependent effects
3 Test apparatus
The apparatus shall consist of the radiation source, electrical test instrumentation, test circuit board(s), cabling, interconnect board or switching system, an appropriate dosimetry measurement system, and an environmental chamber (if required for time-dependent effects measurements). Adequate precautions shall be observed to obtain an electrical measurement system with sufficient insulation, ample shielding, satisfactory grounding, and suitable low noise characteristics. 3.1 Radiation source The radiation source used in the test shall be the uniform field of a 60 Co gamma ray source. Uniformity of the radiation field in the volume where devices are irradiated shall be within ±10 % as measured by the dosimetry system, unless otherwise specified. The intensity of the gamma ray field of the 60 Co source shall be known with an uncertainty of no more than ±5 %. Field uniformity and intensity can be affected by changes in the location of the device with respect to the radiation source and the presence of radiation absorption and scattering materials. 3.2 Dosimetry system An appropriate dosimetry system shall be provided that is capable of carrying out the measurements called for in 220.127.116.11 Electrical test instruments All instrumentation used for electrical measurements shall have the stability, accuracy, and resolution required for accurate measurement of the electrical parameters. Any instrument- ation required to operate in a radiation environment shall be appropriately shielded. 3.4 Test circuit board(s) Devices to be irradiated shall either be mounted on or connected to circuit boards together with any associated circuitry necessary for device biasing during irradiation or for in situ measurements. Unless otherwise specified, all device input terminals and any others which may affect the radiation response shall be electrically connected during irradiation, i.e. not left floating. The geometry and materials of the completed board shall allow uniform irradiation of the devices under test. Good design and construction practices shall be used to prevent oscillations, minimize leakage currents, prevent electrical damage and obtain accurate measurements. Only sockets that are radiation resistant and do not exhibit significant leakages (relative to the devices under test) shall be used to mount devices and associated circuitry to the test board(s).