IEC 60749-17 pdf download

IEC 60749-17 pdf download Semiconductor devices – Mechanical and climatic test methods – Part 17: Neutron irradiation
Once the neutron energy spectrum has been determined and the equivalent monoenergeticfluence calculated, then an appropriate monitor foil (such as 32S,54Fe, or 58Ni) should beused in subsequent irradiations to determine the neutron fluence. Thus, the neutron fluence isdescribed in terms of the equivalent monoenergetic neutron fluence per unit monitor response.Use of a monitor foil to predict the equivalent monoenergetic neutron fluence isvalid only if the energy spectrum remains constant.
2.4.2Dose measurements
lf absorbed dose measurements of the gamma-ray component during the device testirradiations are required, then such measurements shall be made with CaF2 thermo-luminescence dosimeters (TLDs), or their equivalent.These TLDs shall be used in
accordance with the recommendations of recognised national standards or their equivalent.
3Procedure
3.1 Safety requirements
Neutron irradiated devices may be radioactive. Handling and storage of test specimens orequipment subjected to radiation environments shall be governed by the procedures
established by the local Radiation Safety Officer or Health Physicist.
3.2Test samples
Atest sample shall be randomly selected and consist of a minimum of 10 devices, unlessotherwise specified.All sample devices shall have met all the requirements of the relevantspecification for that device.Each device shall be serialised to enable pre- and post-testidentification and comparison.
3.3 Pre-exposure
3.3.1 Electrical tests
Pre-exposure electrical tests shall be performed on each device as required.Where deltaparameter limits are specified, the pre-exposure data shall be recorded.
3.3.2Exposure set-up
Each device shall be mounted unbiased and have its terminal leads either all shorted or allopen. For MOS devices or any microcircuit containing an MOS element, all leads shall beshorted.An appropriate mounting fixture which will accommodate both the sample and therequired dosimeters (at least one actuation foil and one CaF2 TLD) shall be used.Theconfiguration of the mounting fixture will depend on the type of reactor facility used and
should be discussed with the reactor facility personnel.Test devices shall be mounted in sucha way that the total variation of fluence over the entire sample does not exceed 20 percent.Reactor facility personnel shall determine both the position of the fixture and the appropriatepulse level required to achieve the specified neutron fluence level.
3.4 Exposure The test devices and dosimeters shall be exposed to the neutron fluence as specified. If multiple exposures are required, the post-radiation electrical tests shall be performed (see 3.5.1 ) after each exposure. A new set of dosimeters is required for each exposure level. Since the effects of neutrons are cumulative, each additional exposure will have to be determined to give the specified total accumulated fluence. All exposures shall be made at 20 °C ± 1 0 °C and shall be correlated to a 1 MeV equivalent fluence, as described in 2.4.1 .