Why a 12 inch wafer can cost as much as $25,000 in 2025!

How a Silicon Wafer Becomes a Finished IC Chip

A finished integrated circuit begins as purified silicon. The wafer is the foundation. To understand why a single 300 mm wafer can cost as much as 25,000 dollars, you need to see each step before the wafer is cut into individual chips.

Step 1. Purification and Crystal Growth
Manufacturers start with quartz sand. This is refined into electronic-grade silicon with purity above 99.9999999 percent. The Czochralski process grows a large single crystal called an ingot. The ingot is sliced into thin wafers using diamond saws. Each wafer is polished until the surface is flat at the atomic level.

Step 2. Oxidation
A thin layer of silicon dioxide is grown on the wafer surface. This layer insulates and protects future devices. Thermal oxidation requires high heat and controlled oxygen flow.

Step 3. Photolithography
Photolithography defines transistor patterns on the wafer. A photoresist coating is applied. Ultraviolet light exposes the resist through a photomask. The exposed regions are developed, leaving a pattern that guides the next processing step. TSMC uses extreme ultraviolet lithography for nodes at 7 nm and smaller. GlobalFoundries and Analog Devices use deep ultraviolet lithography for larger nodes like 45 nm and 180 nm, which are common for analog and mixed-signal products.

Step 4. Etching
Etching removes material where the resist has been developed away. Plasma etching is common. It removes layers of silicon dioxide, silicon, or metals to match the design.

Step 5. Ion Implantation
Ions are driven into exposed regions of the wafer. This changes the electrical properties of the silicon, forming the source and drain of transistors. The dose and energy of ions are controlled with precision.

Step 6. Deposition
Thin films of materials like silicon nitride, metals, or high-k dielectrics are deposited. Methods include chemical vapor deposition and atomic layer deposition. Each layer contributes to the transistor structure or the wiring above it.

Step 7. Chemical Mechanical Planarization
After multiple depositions, the surface becomes uneven. Chemical mechanical planarization polishes the wafer back to flatness. This step is repeated often to keep the surface smooth for new layers.

Step 8. Metallization and Interconnect
Once transistors are complete, wiring layers connect them. Copper is deposited and patterned in multiple layers. Advanced chips at TSMC may have more than ten interconnect layers. GlobalFoundries and Analog Devices use fewer layers for analog and RF designs, but the principle is the same.

Step 9. Testing at the Wafer Level
Before cutting, manufacturers test the wafer with probe cards. Probes touch each die and measure electrical performance. Passing dies are marked for later packaging. Failed dies are discarded.

Why a 300 mm Wafer Costs 25,000 Dollars

• A modern wafer holds thousands of chips. For example, a 300 mm wafer at 5 nm from TSMC may hold more than 600 high-performance processor dies.

• Each wafer requires hundreds of process steps. Some chips involve more than 70 photomask layers. A single mask set for a 5 nm process can cost over 10 million dollars.

• Extreme ultraviolet scanners from ASML cost over 150 million dollars each. Fab operators like TSMC and GlobalFoundries need many of them to maintain output.

• Yield is not 100 percent. Defects reduce the number of good dies. For analog devices made on mature nodes, yield may be high, but wafers are still expensive due to processing costs. For advanced nodes, yield is lower, which raises the effective wafer cost.

You pay 25,000 dollars for a 300 mm wafer because of the equipment, the materials, and the number of precise steps involved. Each wafer is a record of billions of transistors aligned with nanometer precision.

Purchases a real uncut 12 inch (300mm) wafer from our Silicon Masters Store. It is mounted and framed for display. We can also custom engrave company logos and messages on the backing the wafer is mounted. Great for gifts and awards!   

 

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