Fan-Out Embedded Bridge Structure for CoPackaged Optics Characterization and Evaluation

According to datacenter, artificial intelligence /machine learning (AI/ML) and high-performance computing (HPC) requirement at the future, high speed of data transmission is demanding recently to meet the target. Therefore, CPO (Co-packaged optics) is the solution for increasing the data transmission rate and supporting high-bandwidth applications due to copper interconnects are reaching the bandwidth-distance limits immediately. The structure of Optics engine (OE) can be divided by two parts: EIC (electrical integration die) and PIC (Photonics integration die) into a single package which shorten the optic and electrons signal transmission path and enhance the transition efficiency.The structure of CPO is assembled by switch die and FO-EB (Fan-Out Embedded Bridge) structure which is combined with PIC and EIC dies into single package. This paper will provide the CPO structure and material suggestions for the assembly processes and reliability. In the beginning, glass candidates would be studied for wafer warpage for FO process such as pre-molding, u-pad, 2nd bonding, C4 and 3rd bonding process. Regarding this subject, it would come out the different glass combinations which could be in criteria during the wafer warpage process and show good alignment with experimental data. After in process warpage investigations, the next challenge is PIC die to bond on fan-out chip module with overhang design. The structure suggestions of FO-EB would be studied in parallel for warpage investigations. Finally, the paper will also provide the substrate core and heat sink adhesive material suggestions to solve package warpage and reliability risk.Using simulation for material and structure selections, CPO package would have a guide in process warpage and reliability test. According to that, it helps package development to save the time and resource for DOE and reduce the stress and warpage risk.