New LED Technology Challenges for X-Ray

Tuesday, May 22
2:30pm to 3:00pm

Recent advances in LED technology have placed increased demands on the joint interfaces and materials used during production. Higher power, smaller size and increased reliability requirements intensify the need for higher quality more consistent production output. Flaws in the products can no longer be accepted as the performance requirements have increased dramatically, high power means higher temperatures and this needs very good thermal conductivity to move heat away from the key areas allowing the LED to last longer, as heat stresses the interfaces causing delamination or die fractures. Poor bond joints mean less transmission of power and this will reduce the life time of the components or their ability to perform at the required level. Many LEDs are potted or encapsulated and after this process the only non-destructive test option is x-ray, so as the requirement for LED inspection grows the need for high quality x-ray systems increases. This presentation will look at the common LED faults, most of which are only visible using x-ray technology and show good pass and fail images, also some of the recent technology advances in x-ray which make these images possible. Voiding is becoming more relevant too as there is a direct correlation between voids and thermal transfer and therefore reliability and product lifetime. We will look at technology which allows measurement of voids in individual interface areas of the assembly at the same time and see a video of an automated inspection routine measuring different areas on individual LEDs which are assembled onto a printed circuit board and how the voiding percentage in each area can be compared to pre-set acceptable limits. The concluding part of the presentation will include some 3D computer tomography images which could best be described as e micro-sections, these reconstructed images can be zoomed and cut though in any direction allowing the operator to look at any features within the structure. This technology produces great and very detailed images and with the latest powerful reconstruction and manipulation software allows the user to see details not previously seen before.

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