An RDL-First Fan-Out Panel-Level Package for Heterogeneous Integration Applications

Abstract

Technologies of Fan-outpanel-level packaging (FOPLP) are studies in this paper. First, the warpage control of a molded panel is a crucial problem for FOWLP technology development. In this paper, finite element analysis (FEA) is applied to study the influence of back end of the line (BEOL) process-induced warpage, as well as characterization for simulation, and investigation of each single process. In our process, a liquid release material is coated onto a 370 mm x 470 mm glass carrier. After baking, three layers of redistribution layer (RDL), passivation, and Cu leads are fabricated on the panel with coating, exposing, developing, lithography, and electroplating processes. Silicon test chips with a size of 16 mm x 10 mm and micro solder bumps with a pitch of 90 mu m are thinned down to 150 mu m. Test chips are then flip-chip bonded onto glass carrier with pre-bond and reflow proces. After panel molding, a laser debonding method, another key technology advancement, is utilized for panel debond. Debond performance, which is directly related to laser parameter and panel-level package (PLP) structure, is critical. After debonding, the molded panel is cleaned, followed by dicing and OSP coating processes, and then the electrical performance of the interconnection is evaluated. Reliability tests at the component level, such as pre-condition, thermal cycling test (TCT), and unbiased HAST (uHAST), are performed. The demonstration of RDL-first PLP technology without interposers proves its great potential in heterogeneous integration applications.