In semiconductor manufacturing, intellectual property (IP) cores/blocks play a dominant role in modern chip design. The driving factor for IP usage is the time-to-market benefit delivered through design reuse. Today, IP blocks include the entire range of modules, ranging from standard cells, memories, and I/O devices to CPUs. Chip designers need complex IP blocks because modern levels of integration allow chips to be a complete system on chip (SOC), not just components of systems. However, as chips become more complex, IP blocks are subject to more interactions from multiple neighboring modules in the chip. Current IP block quality assurance (QA) flows focus mainly on functional verification, performance verification, and design rule checking (DRC). The standard DRC deck checks for minimum and maximum density rules within the IP block. However, when an IP is placed in an SOC, it may encounter complex surrounding scenarios, as when a low density IP is placed next to a higher density area. During integrated circuit (IC) manufacturing, the resulting proximity effects may cause failures or electrical targeting mismatches within the IP, due to etch micro-loading and long-range CMP interactions. Designers can only locate these chemical mechanical polishing (CMP) hotspots related to IP placement in the SOC near the end of the design flow, which limits any floorplan changes to fix the hotspots. Standalone IP block QA is insufficient to detect possible layout- or floorplan-induced problems that can affect manufacturing. In this paper, we present a CMP modeling methodology to guard-band IP against topography variations that can occur after IP placement in the SOC design. We emulate low, average, and high-density scenarios surrounding the IP blocks, followed by CMP simulations and hotspot detection using silicon-calibrated CMP models. After simulation, guidelines provided to fix these CMP hotspots surrounding the IP blocks during early design stages to improve manufacturability and yield. This flow will make IPs robust from CMP hotspots that typically appear after SOC floorplanning.
Chemical-mechanical polishing (CMP) is a key process in integrated circuit (IC) manufacturing. Successful fabrication of semiconductor devices is highly dependent on the final planarity of the processed layers. Post-CMP topography variation may cause degradation of the circuit performance. Moreover, the depth-of-focus (DOF) requirement is critical for lithography of subsequent layers. As such, planarity requirements are critical for maintaining IC manufacturing technology scaling trends, and supporting device innovation. To mitigate post-CMP planarity issues, dummy fill insertion has become a commonly-used technique. Many factors impact dummy fill insertion results, including fill shapes, sizes, and the spacing between both fill shapes and the drawn layout patterns. The goal of the CMP engineer is to optimize design planarity, but the variety of fill options means just verifying the design rules for fill is a challenging task. This data collection currently requires a long development cycle, consuming a great deal of time and resources. In this paper, we show how CMP modeling can help resolve these issues by applying CMP modeling and simulations to drive Calibre YieldEnhancer SmartFill parameters that have been optimized for dummy fill. Additional capabilities in the SmartFill functionality automate CMP hotspot fixing steps. Using CMP simulations, engineers can get feedback about post-CMP planarity for given fill options in a much shorter time. Not only does this move dummy fill optimization experiments from a real lab into a virtual lab of CMP modeling and simulation, but it also provides more time for these experiments, providing improved results.