Unveiling the ASIC Design Flow in VLSI Engineering Services.

Designing an ASIC (application-specific integrated circuit) is a complex and fascinating journey that entails various steps, from concept to tape-outs. Despite the miniature size of the end product, this process is filled with engineering challenges that require expertise and attention to detail. In this blog post, we will take a quick dive into the ASIC design flow, highlighting its importance and the steps involved.

Why Adopt the ASIC Design Flow?

The ASIC design flow is crucial to ensure successful chip design. It is based on a comprehensive understanding of ASIC specifications, requirements, low power design, and performance. By following a proven ASIC design flow, engineers can streamline the process and meet crucial time-to-market goals. Each stage of the ASIC design cycle is supported by powerful EDA (Electronic Design Automation) tools that facilitate the implementation of the design.

How Does the ASIC Design Cycle Work?

To meet the evolving demands of chip design, it is necessary to adapt design tools, methodologies, and software/hardware capabilities. The ASIC design flow, adopted by engineers for efficient structured ASIC chip architecture, focuses on design functionalities that align with future requirements.

Step 1: Chip Specification At this stage, engineers define the features, microarchitecture, functionalities, and specifications of the ASIC. The design team generates RTL (Register Transfer Level) code, while the verification team creates a test bench to validate the design.

Step 2: Design Entry / Functional Verification Functional verification ensures the logical behavior and functionality of the circuit through simulation. The design and verification teams collaborate to generate RTL code using test benches. This simulation process aims to achieve high code coverage, including statement, expression, branch, and toggle coverage.

Step 3: RTL Block Synthesis / RTL Function The RTL team translates the RTL code into a gate-level netlist using logical synthesis tools. This step involves meeting timing constraints and creates a synthesized database of the ASIC design.

Step 4: Chip Partitioning Engineers follow ASIC design layout requirements to create the structure of the chip. This involves partitioning the ASIC into functional blocks, considering performance, technical feasibility, and resource allocation.

Step 5: Design for Test (DFT) Insertion Design for Test techniques are crucial in ensuring a high-quality ASIC. This includes scan path insertion, memory built-in self-test, and automatic test pattern generation to detect and rectify faults during production.

Step 6: Floor Planning (Blueprint Your Chip) Floorplanning involves placing blocks on the chip, determining its size, and connecting them with wires. Engineers ensure proper wire length and functionality to avoid interference and signal delays.

Step 7: Placement Placement involves placing standard cells in rows while considering factors such as timing requirements, net lengths, power dissipation, and performance.

Step 8: Clock Tree Synthesis Clock tree synthesis builds the clock tree, meeting timing, area, and power requirements. Various structures like mesh, H-tree, or fishbone are used to optimize clock tree synthesis and minimize power consumption.

Step 9: Routing Routing is divided into global routing and detailed routing. Global routing estimates net delays, while detailed routing calculates actual wire delays using optimization methods.

Step 10: Final Verification (Physical Verification and Timing) The layout undergoes physical verification checks such as layout versus schematic, design rule checks, and logical equivalence checks to ensure correctness before tapeout.

Step 11: GDS II - Graphical Data Stream Information Interchange In the final stage, the engineer performs wafer processing, packaging, testing, and verification. The GDSII file is used by semiconductor foundries to fabricate the silicon.

Conclusion: The ASIC flow in VLSI is a mature and silicon-proven process that enables engineers to develop efficient and high-performance chips. By following a structured approach and leveraging powerful EDA tools, engineers can navigate the complexities of ASIC design and meet the demands of the market. eInfochips, a leading ASIC design and verification service provider, offers comprehensive assistance in low power ASIC design, ensuring successful chip development.