IEC 60749-30:2020 pdf download – Semiconductor devices – Mechanical and climatic test methods – Part 30: Preconditioning of non-hermetic surface mount devices prior to reliability testing.
5.2 Moisture chamber Moisture chamber(s) capable of operating at 85 °C/85 % RH (relative humidity), 85 °C/60 % RH, 85 °C/30 % RH, 30 °C/70 % RH and 30 °C/60 % RH. Within the chamber working area, temperature tolerance shall be ±2 °C and the RH tolerance shall be ±3 % RH. A chamber with 60 °C/60 % RH capability is optional for accelerated soak conditions. 5.3 Solder equipment Solder equipment shall consist of the following. a) 1 00 % convection reflow system capable of maintaining the reflow profiles required by this document. This is the preferred equipment for solder reflow. b) VPR (vapour phase reflow) chamber capable of operating the temperature profiles in IEC 60749-20 with appropriate fluids. The chamber shall be capable of heating the packages without collapsing the vapour blanket and of re-condensing the vapour to minimize loss of the vapour phase soldering liquid. The vapour phase soldering fluid shall vaporize at the appropriate temperature specified above. c) Infrared (IR)/convection solder reflow equipment capable of maintaining the reflow profiles required by this document. It is recommended that this equipment use the IR to heat the air and not directly impinge upon the components under test. d) Wave-solder equipment capable of maintaining the conditions in 6.4.4 of IEC 60749-20:2020. NOTE The moisture sensitivity condition (classification) test results are dependent upon the package body temperature, rather than board or lead temperature. Convection and VPR are known to be more controllable and repeatable than IR. When there are correlation problems between VPR, IR/convection, convection and wave solder (if used), the convection results are considered as the standard. 5.4 Optical microscope Optical microscope (40X for external visual examination). 5.5 Electrical test equipment Electrical test equipment capable of performing room temperature DC and functional tests.
6.2 Initial measurements 6.2.1 Electrical test Perform an electrical DC test and functional test to verify that the devices meet the room temperature data sheet specification. Replace any devices that fail to meet this requirement. 6.2.2 Visual inspection Perform an external visual examination under 40X optical magnification to ensure that no devices with external cracks or other damage are used in this test method. If mechanical rejects are found, corrective action shall be implemented in the manufacturing process and a new sample drawn from a product which has been processed with the corrective action. 6.3 Temperature cycling (optional) Perform 5 cycles of temperature cycle from −40 °C (or lower) to +60 °C (or higher) to simulate shipping conditions (the shippability option). This step is optional unless required by the relevant specification. 6.4 Drying (bake out) Bake the devices for at least 24 h minimum at (1 25 ± 5) °C. This step is intended to remove moisture from the package so that it will be “dry”. NOTE 1 This time is modified if desorption data on the particular device being preconditioned shows that more or less time is required to obtain a “dry” package. NOTE 2 If the preconditioning sequence is being performed by the semiconductor manufacturer, steps 6.2.1 , 6.2.2 and 6.4 are optional since they are at the supplier’s own risk. If the preconditioning sequence is being performed by the user, step 6.8 is optional. 6.5 Soak conditions for dry-packed SMDs 6.5.1 General The following soak conditions shall apply.
6.7 Solder reflow 6.7.1 Solder reflow procedure Not sooner than 1 5 min and not longer than 4 h after removal from the temperature/humidity chamber, submit the devices to three cycles of the appropriate reflow conditions in accordance with IEC 60749-20. All temperatures refer to the top surface of the package. The sample parts shall be cooled sufficiently for at least 5 min (preferably back to room temperature) between reflow cycles so that the reflow temperatures/times of the samples are not affected on the subsequent reflow cycles. Reflow practices shall be sufficient to ensure that all sample parts, in each reflow cycle, will meet the appropriate reflow profile requirements of IEC 60749-20. SMDs intended for use in a “Pb-free” assembly process shall be evaluated using the “Pb-free” reflow temperature whether or not the SMD is Pb-free. If parts are reflowed in other than the normal assembly reflow orientation (i.e. live-bug/dead-bug) the damage response shall be correlated. The reflow oven shall be loaded with the same configuration or be verified to have an equivalent thermal load when running preconditioning as was used to develop the reflow profile. The reflow profiles in IEC 60749-20 are only for classification and preconditioning and are not intended to specify board assembly profiles. Actual board assembly profiles shall be developed based on specific process needs and board designs and shall not exceed the parameters in IEC 60749-20.