Voids on sealing area.

Voids on sealing area. Observation by X-Ray. Validation by Seal Test.

Further analysis may be necessary in order to confirm whether there are real voids on sealing area, as well to determine the hermeticity of components with designed internal cavities, despite not having whole sealing.

External Visual inspection provides the first warning about possible sealing area defects, even though this preliminary observation is not enough to confirm the fault.

Would it be enough the sealing material applied at internal area in order to ensure the proper isolation between external and internal environments?

• First point to answer this question:

X-Ray inspection is the non-invasive test that allows to assess part construction, where naked eye does not reach.

As an example, next images are showing external top, lateral and bottom views that belongs to a microcircuit with CCGA-624 package for space application under evaluation:

Whereas X-ray image displays the real sealing material applied all around device perimeter:

• Second point:

Seal Test is recommended to be carried out, both Fine Leak and Gross Leak. In this way, although X-Ray discloses a weak point, parts hermeticity will be validated by Seal Test successful outcomes.

Seal Test must be performed according applicable MIL/ ESCC Methods, which depends on each part family:

• • MIL-STD-883, Method 1014.13 (for integrated circuit components, and other families as specified)
  • MIL-STD-750, Method 1071.8 (for discrete families)
  • MIL-STD-202, Method 112 (for Tantalum Capacitors with cavity)
  • ESCC Basic Specification No. 21100 (test methods, conditions, procedures and requirements specified herein are closely based on hermetic seal tests specified in MIL-STD-750 and MIL-STD-883)