IEC 60749-18:2002 pdf free download

IEC 60749-18:2002 pdf free download Semiconductor devices – Mechanical and climatic test methods – Part 18: Ionizing radiation (total dose)|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 ±1 0 % 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 4.2.
3.3 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).
All apparatus used repeatedly in radiation fields shall be checked periodically for physical or electrical degradation. Components which are placed on the test circuit board, other than devices under test, shall be insensitive to the accumulated radiation or they shall be shielded from the radiation. Test fixtures shall be made such that materials will not perturb the uniformity of the radiation field intensity on the devices under test.