Design and Demonstration of Paper-Thin and Low-Warpage Single and 3D Organic Packages with Chip-Last Embedding Technology for Smart Mobile Applications

This paper presents innovations and advances in demonstrating paper-thin organic packages with low warpage. These advances include: 1) Reduction in over-all substrate warpage, 2) Ultra-low stand off interconnection height, 3) Ultra-thin (30 mu m core thickness) and ultra-low CTE (1-5 ppm/oC) organic substrates, 4) Assembly of large die onto the ultra-thin substrate, and 5) Assembly to form advanced package-on-package using conventional batch-type SMT reflow processes. Design, fabrication, assembly and characterization of test-vehicles demonstrating all these innovations are described in this paper. Comprehensive warpage modeling is performed by taking into account all substrate fabrication and assembly steps. The measured warpage data after package fabrication and assembly was used to refine and validate the models. Optimized geometry and material parameters are designed from the validated models.