Designing Silicon Interposers for 2.5/3DIC Heterogeneous Integration - Meeting Foundry and OSAT Requirements

Abstract

End market demand for higher performance, higher bandwidth and higher throughput processing such as AI, HPC, VR, 5G and even autonomous vehicles is driving the trend of heterogenous integration of ASICs, chiplets and memory, including HBM, onto advanced high-performance substrates using 2.5 and 3D IC assembly techniques that are manufactured using silicon or silicon-like processes. There are multiple suppliers of such advanced high-performance substrates ranging from the one stop mega foundries to multiple OSATs of different sizes. It’s fair to say that all of them have common design requirements or constraints that must pass a rigorous verification process of the manufacturing mask files (GDSII or OASIS). Such GDSII or OASIS files are post processed or exported from the physical design tools making the need to create the mask files with 100% fidelity an additional challenge to the design team. In this paper we will cover the major steps needed to design and implement an advanced silicon-based interposer that addresses common requirements of foundries and OSATs. We will talk about what each step is, why its required, any challenges that exist in addressing the step and actual design examples for each step. The major steps we will cover include: * What information you need from your manufacturer? * Definition of connectivity & floorplanning of the interposer * Defining the interposer materials stackup & vias for routing * Breakout or fanout routing from chiplet or IC pads * Power and ground mesh creation * Routing of interposer connectivity * Generation of interposer manufacturing data (GDS/OASIS) * Verification of the design to meet foundry/OSATs rules * Handoff to foundry/OSAT At the end of this paper attendees will understand what the major workflow steps for interposer design are and why. What general information they will need to obtain from their manufacturer in order to start design and how to use it. They will learn what each design step entails with clear examples which will enable creation of workflows to successfully handoff their designs to their chosen foundry or OSAT manufacturer.