Challenges exist for wafer preparation and die attach process in processing thin dice with thickness ranging from 50 µm to 120 µm, or even up to 30 µm thicknes

Bryan Christian S. Bacquian

Frederick Ray I. Gomez

English

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International Research Journal of Advanced Engineering and Science  ISSN (Online): 2455-9024   151  Bryan Christian S. Bacquian and Frederick Ray I. Gomez, “Die Backside Augmentation for Die Crack Mitigation,” International Research Journal of Advanced Engineering and Science, Volume 4, Issue 2, pp. 151, 2019. Die Backside Augmentation for Die Crack Mitigation  Bryan Christian S. Bacquian, Frederick Ray I. Gomez Central Engineering and Development Department, Back-End Manufacturing & Technology STMicroelectronics, Inc., Calamba City, Laguna, Philippines 4027   Keywords— Wafer preparation; backside surface subtractive method; die crack; thin die; die attach. I. OVERVIEW  Challenges exist for wafer preparation and die attach process in processing thin dice with thickness ranging from 50 µm to 120 µm, or even up to 30 µm thickness  Typical assembly process flow in Fig. 1 shows the mentioned processes at the forefront Fig. 1.  Assembly manufacturing process flow. II. PROBLEM IDENTIFICATION  Die crack issues on thin die applications (with 50 µm to 120 µm die thickness) propagated during pick-up process of diebonder machine, as illustrated in Fig. 2  One reason behind this die crack defect or issue is the die adhesion to mounting tape   Fig. 2.  Die crack encountered during pick-up process at die attach station.  With the increasing demand on thin die applications, mitigation of die crack issues is one big challenge during pick-up process of diebonder machine III. PROCESS DESIGN SOLUTION  Silicon die backside area is augmented by reducing the area by 50% or less with depth of 10 µm as depicted in Fig. 3, through the application of backside surface subtractive method  This critical process utilizes a grinding wheel type material (like a dicing saw) to grind 10 µm from the backside surface  Fig. 3. Silicon die backside augmentation through subtractive method application.  Infrared camera will guide the wafer sawing machine during the process since standard sawing machine is not capable of aligning an object without unique pattern  With the area of die with direct contact on mounting tape reduced, adhesion strength of die to mounting tape is then reduced, thus eliminating the possibility of die crack issue  Another advantage for the design is the anchoring effect of the grooved area for thin die with glue applications 

Die Backside Augmentation for Die Crack Mitigation

https://zenodo.org/record/2673082/files/IRJAES-V4N2P425Y19.pdf

Die Backside Augmentation for Die Crack Mitigation

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