IEC 60749-39-2021 Semiconductor devices – Mechanical and climatic test methods – Part 39: Measurement of moisture diffusivity and water solubility in organic materials used for semiconductor components

IEC 60749-39-2021 Semiconductor devices – Mechanical and climatic test methods – Part 39: Measurement of moisture diffusivity and water solubility in organic materials used for semiconductor components. 6 Procedure 6.1 Sample preparation 6.1.1 Process and cure the samples using recommended processing conditions in accordance with the manufacturer’s specification. 6.1.2 To obtain the appropriate sample thickness as given by Formulae (1 ) or (2), samples can be sectioned and finely polished from larger specimens. Near parallel-sided flatness shall be maintained for samples prepared in this manner. The prepared samples should be inspected for voids, both internal and surface, using acoustic microscopy or x-ray. The ideal samples should be nearly void-free. 6.2 Absorption measurements below 1 00 °C 6.2.1 Measure the linear dimensions of the prepared sample to the nearest ±0,02 mm. Record the sample thickness, h, and calculate the sample volume, V, using the appropriate geometric relationship based on the sample shape. NOTE Calculating the volume by measuring the linear dimensions is never accurate. The error is smaller when the sample is big. One accurate way of determining the volume is to use Archimedes’s principle, which is to measure the sample weight in air and immersed in a liquid with known density (ethyl alcohol, IPA, etc.). In this way, the volume of a sample with irregular shape can also be determined. 6.2.2 The dry weight of the sample shall be determined, in accordance with IEC 60749-20, firstly by baking the sample for 24 h at 1 25 +5/-0 °C and continuing to bake and weigh the sample every 1 2 hours until no further weight loss is observed to ensure that the sample(s) are dry. The dry weight is determined when no further weight loss is observed, less than 0,002 % difference, after two consecutive measurements with a minimum baking interval of 1 2 h. Within 30 minutes after removal from the oven, weigh the sample(s) using the analytical balance equipment described in 4.1 and determine the dry weight in accordance with 6.2.4. In accordance with IEC 60749-20, small sample(s) (less than 1 ,5 mm total height), devices should be weighed within 30 minutes after removal from oven. 6.2.3 Remove the sample from the bake oven and immediately cool by placing in contact with the heat sink of 4.5. If more than one sample is to be measured, the samples and heat sink should be placed into a desiccator to limit...