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Notes on Microchip Manufacturing Process

Jul 29, 2024

Microchip Manufacturing Process

Overview

  • Modern smartphones have 62 microchips with 90 billion transistors.
  • Microchips are produced in large semiconductor fabrication plants (fabs).
  • Fabs have clean rooms spanning the area of 8 football fields with machines costing millions.

Manufacturing Journey

  • Silicon Wafer Production

    • Silicon wafers are the building blocks of microchips.
    • Wafers undergo about 1,000 processes over a 3-month period in fabs.
    • Each wafer ends with hundreds of CPU chips, each containing approximately 26 billion transistors.
  • Layers and Components

    • Integrated circuits consist of layers of metal wires and transistors.
    • Each CPU chip has cores, memory controllers, and graphics processors.
    • A block diagram shows the architecture including multiply blocks with thousands of transistors and layers.

Steps in Microchip Manufacturing

  1. Analogy of Baking Cake

    • Building a microchip is compared to baking an 80-layer cake with 940 steps.
    • Precision is critical; a deviation of over 1% can ruin the product.
  2. Layer Construction

    • Depositing Layers: Silicon dioxide as insulating layer and photomask application.
    • Etching: Using solvents to create patterns by removing material.
    • Finalization: Each layer’s surface is leveled and prepared for additional layers.
  3. Transistor Manufacturing

    • Involves more complex steps compared to metal wire layers. Includes cleaning and inspecting stages.
    • Transistors: FinFETs - extremely small (dimensions of 36 x 6 x 52 nm).

Semiconductor Fabrication Plant Components

  • Silicon Wafer Specs

    • A 300mm wafer hosts numerous CPU chips (230 CPU chips per wafer).
    • Wafer transport via front opening universal pods (FOUP) using overhead systems.
  • Production Tools

    • Categories of Tools:
      • Making mask layers (e.g., photolithography).
      • Adding and removing materials (etching, CMP).
      • Cleaning and inspecting wafers (using water, scanning electron microscopes).

Detailed Tool Functions

  • Photolithography Tool

    • Critical for transferring designs from photomask to wafer using UV light.
    • Integral in creating nanoscopic transistor patterns.
  • Deposition and Removal Tools

    • Deposition Tools: Add materials (metals, insulators) using varied methods.
    • Etching Tools: Remove materials using chemical or plasma processes.
    • CMP: Ensures wafer surface is flat and ready for new layers.
  • Ion Implantation

    • Modifies silicon to establish P and N regions for transistors, followed by annealing to repair lattice damage.
  • Cleaning and Inspection

    • Regular cleaning to prevent contamination, ensuring nanoscale precision in production.

Post-Manufacturing Steps

  • Wafer Testing: Each CPU is rigorously tested for functionality; defective sections are categorized.
  • Cutting: Wafers are laser-cut, and chips are placed on interposers and then tested.
  • Final Assembly: CPUs are mounted, heat spreaders added, followed by final testing before packaging.

Conclusion

  • The entire microchip manufacturing process requires advanced science and technology.
  • Continual learning resources are available via platforms like Brilliant.org for deeper understanding.
  • Upcoming videos planned on related topics like GPU architecture and transistor physics.

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