In the wave of technological innovation, the field of integrated circuit design has ushered in a revolutionary way of thinking. Concepts such as Cubic IC (Cubic IC), Isochronous Transfer Area (ITA), Litus Space (LITS) and Effective Functional Volume (EFV), which were first mentioned on August 7, 2021, seemed quite advanced at the time. But as time goes by, these ideas that were once considered fanciful have gradually found a foothold in the real world. Just as Moore's Law was incredible when it was first proposed, we can now integrate more than 100 million transistors on tiny chips of less than one square millimeter. Today, two years later, I still believe that these innovative ideas are worth exploring in depth again and recommending them to readers.
1. Integrated circuit design innovation from a three-dimensional perspective
In traditional large-scale integrated circuit (IC) design, designers usually integrate the entire electronic system on a single chip, including a microprocessor, analog IP core, digital IP core and memory or off-chip storage control interface wait. This process is based on two-dimensional integration technology, in which all transistor functional units are located on the same plane.
However, as system complexity continues to increase, the increase in chip area has become an inevitable problem, which directly affects the chip yield. In addition, as technological progress approaches physical limits, the boundaries of Moore's Law are becoming increasingly apparent. As a result, people began to seek new solutions, such as system-in-package (SiP) and advanced packaging technology, chipset (Chiplet) and heterogeneous integration technology, etc., which have become the key to the continuation of Moore's Law.
In this context, we proposed an innovative idea: designing integrated circuits from a three-dimensional perspective. Taking the design of a system-on-a-chip (SoC) as an example, we no longer design all components on the same wafer plane, but distribute them on different levels (storey), and combine these levels to form a complete chip system. As shown in the figure below, each Storey has a layer of transistors and is interconnected through multi-layer wiring. Different Storeys are mainly interconnected through silicon vias (TSV) and redistribution layers (RDL).
This design method means that different Storeys can be manufactured using different process nodes, while transistors on the same level need to use the same process. This is not only a fusion of integrated circuit design and advanced packaging design, but also a brand-new design concept. The difficulty lies in the innovation and adaptation of EDA tools.
2. New era requirements for EDA tools
Traditional IC layout design tools design transistors, resistors, and capacitors on a silicon substrate and realize their interconnection through multi-layer wiring. However, under the new design idea, when there are multiple Storeys, we must not only consider the signal interconnection and wiring within the Storey, but also the interconnection between Storeys.
This requires EDA tools to have three-dimensional network and wiring design capabilities, as well as multi-layout network optimization capabilities. In other words, this tool should be able to optimize network connections between multiple layouts in a space at the same time. Multiple layouts can exist in the form of virtual stacks in the same design environment, or in different design environments, but the data interaction between them needs to be coordinated and managed uniformly.
There are currently no EDA tools on the market that fully meet this demand, but tools that come close to this demand have emerged in the field of advanced packaging design, such as the high-density advanced packaging design tool HDAP. In addition to design tools, EDA simulation and verification tools must also keep up with the pace of development. First, simulation and verification tools need to be able to correctly parse complex data models. Secondly, simulation tools need to use more powerful algorithms to perform simulations and obtain accurate results, while verification tools need to ensure the accuracy and precision of data from design to production.
Conclusion:
As the field of integrated circuit design continues to develop and change, we are faced with unlimited possibilities and challenges. The integrated circuit design idea from a three-dimensional perspective proposed in this article is not only a challenge to traditional design methods, but also a bold innovation to existing technology. It heralds the future direction of integrated circuit design and will lead us into a new era of more efficient and complex electronic design. Despite the many challenges, we have reason to believe that with the continuous advancement and innovation of technology, this day will become a reality.