On the analysis of dynamic effect in the die pick-up process

During electronic packaging, local breakage or scratch marks on the backside of semiconductor dice are potential risks leading to failure in the subsequent packaging processes or in service. Contact-impact effect in the die pick-up process may be one of the main reasons causing the defects. To investigate the contact-impact effect, finite element analyses are performed by Abaqus/Explicit 6.8.1, considering three key factors involving impact speed, distance from the contact center and whether to penetrate the substrate or not. The conclusions are that, impact effect by ejecting needle takes effect only in limited area around the contact point and can boost local stress greatly by 8~10 times which may result in local damage to chips as observed by microscopy. Impact effect attenuates quickly with distance from the contact center. Without penetration of substrate, it does not at all contribute to the local cracking issue of chips. However, it really does with the penetration present, and the critical velocity can be evaluated using the same method as the paper. For the pick-up process, penetration should be avoided for securing the precious semiconductor chips, that is to say, tougher substrate material, right ejecting needle as well as proper velocity and height of ejecting is to be adopted.