Semiconductor Wafer Size and Thickness Reference (2 inch to 450 mm)
This table lists the standard silicon wafer diameters from 2 inch to the proposed 450 mm, with nominal thickness, circular area and the kind of product each size is typically used for. It is a quick lookup for process engineers, planners and buyers who need to compare wafer sizes without searching several datasheets.
| Nominal diameter | Diameter (mm) | Typical thickness (um) | Area (cm2) | Typical use today |
|---|---|---|---|---|
2 inch | 50.8 | 279 | 20.27 | Legacy R&D, some compound semiconductors and optoelectronics |
3 inch | 76.2 | 381 | 45.6 | Legacy devices, university and compound semiconductor lines |
100 mm (4 inch) | 100 | 525 | 78.54 | Compound semiconductors (GaAs, InP, SiC), MEMS, discretes |
125 mm (5 inch) | 125 | 625 | 122.72 | Rare today, older power and discrete lines |
150 mm (6 inch) | 150 | 675 | 176.71 | Power devices, SiC, GaAs, MEMS, sensors, legacy analog |
200 mm (8 inch) | 200 | 725 | 314.16 | Analog, mixed signal, power management, MEMS, mature-node logic |
300 mm (12 inch) | 300 | 775 | 706.86 | Advanced logic, DRAM, NAND, high-volume mature-node production |
450 mm (18 inch) | 450 | 925 | 1,590.43 | Proposed standard, not adopted in volume production |
Thickness is the nominal value associated with the SEMI silicon wafer specifications for prime wafers of each diameter. Actual purchase specs carry tolerances, and thinned wafers (after backgrind) are far thinner. Area is the full circle, not usable area after edge exclusion. Always confirm against your wafer supplier datasheet.
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How to use the table
Type a diameter such as 200 or a use such as MEMS into the search box to filter rows. Use the area column to compare how much silicon each size offers per wafer start, which is the first step in estimating die per wafer and cost per die. Export the table to Excel or PDF to attach to a sourcing note or an equipment specification.
- Search by diameter in mm or inches
- Compare area to see why 300 mm is about 2.25 times 200 mm
- Use the use column to sanity check tool compatibility
Why thickness grows with diameter
A larger wafer must be thicker to stay mechanically stable during handling, thermal cycles and chuck clamping. That is why a 300 mm wafer is nominally 775 um while a 100 mm wafer is 525 um. Thicker wafers also mean more silicon per wafer and heavier cassettes. Product wafers are often thinned later in backend processing for power devices, stacked memory and thin packages.
Worked example: area ratio
A 300 mm wafer has an area of about 707 cm2 and a 200 mm wafer about 314 cm2. The ratio is 2.25, so a 300 mm wafer carries more than twice the die of a 200 mm wafer for the same die size, before edge loss. Edge loss falls as a fraction on larger wafers, so the real die gain is slightly higher. Use a dies-per-wafer calculation for the exact number.
Common mistakes
Do not confuse the nominal diameter in inches with the exact metric value. A 6 inch wafer is 150 mm, not 152.4 mm, in the SEMI specifications. Do not assume every tool in a fab handles every size, because most process equipment is built for one diameter. Finally, remember that SOI, SiC and GaAs wafers have their own specifications that differ from prime silicon.
Frequently Asked Questions
What is the standard thickness of a 300 mm wafer?
The nominal thickness associated with a 300 mm prime silicon wafer is 775 um. Actual purchase specifications include tolerances, and wafers are typically thinned after front-end processing for many products. Always confirm with your wafer supplier datasheet.
Why did the industry not adopt 450 mm wafers?
A 450 mm standard was proposed and pilot work was done, but the equipment cost, ecosystem readiness and economics did not justify a volume transition. Fabs kept investing in 300 mm capacity instead.
Is the area column the usable area?
No. It is the full circle area computed from the nominal diameter. Usable area is smaller after edge exclusion, flat or notch, scribe lanes and test structures, which is why a dies-per-wafer calculation is needed.
Which wafer size is used for SiC power devices?
SiC production has mostly used 150 mm wafers, with a move toward 200 mm underway across the industry. Check your supplier roadmap for current availability.
If your ERP or MES tracks wafers, lots and starts by diameter, Netray can help expose that data for planning questions in plain language, on your own infrastructure.
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