Silicon Wafers with JEIDA Flats for R&D
What Types of Silicon Wafer Flats are Available?
The two most common types of wafer flats are the JEIDA and the SEMI standard. JEIDA wafers are smaller than SEMI standards and are used in Japan to orient substrate. Those in the rest of the world, including North America, use SEMI standards. The SEMI standard is the most common type of wafer. It can be used for all kinds of electronics. These specifications are available in many formats, so make sure you check the specifications before making a purchase.
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How are JEIDA Flats Different from SEMI Standard Flats?
JEIDA flats are 10mm smaller repectively than SEMI standards flats.
What is a Jeida Flat?
Jeida sounds like a Star Wars character, but it's not. Jeida flats are the Japanese standards length of edges cut out of round flats. The wafers are used for semiconductor purposes.
JEIDA Flats are the Japanese version of cuts in the wafer used for orienting the substrate. Unlike standard flats found in the rest of the world, JEIDA FLATS are 10mm shorter than SEMI standard on silicon wafers..
The rest of the world uses Semiconductor Standard Flats.
| Wafer Dimension Specification SEMI and JEIDA |
| DIAMETER | Dimension Tolerance |
SEMI JEIDA |
50.80 50.00 |
60.00 | 76.20 76.00 |
80.00 | 90.00 90.00 |
100.00 100.00 |
125.00 125.00 |
150.00 150.00 |
200.00 200.00 |
|
| SEMI JEIDA |
0.38 0.5 |
0.5 | 0.63 0.5 |
0.5 | 0.5 0.5 |
0.5 0.5 |
0.2 0.5 |
0.2 0.5 |
0.2 0.5 |
|||
| THICKNESS | Dimension Tolerance |
SEMI JEIDA |
0.279 0.280 |
0.330 | 0.381 0.380 |
0.400 | 0.475 0.475 |
0.52 0.525 |
0.625 | 0.625 0.625 |
0.675 0.625 |
0.725 0.725 |
| SEMI JEIDA |
0.025 0.010 |
0.015 | 0.025 0.015 |
0.025 | 0.025 0.025 |
0.020 0.015 |
0.020 0.015 |
0.020 0.015 |
0.020 0.025 |
|||
| PRIMARY FLAT LENGTH | Dimension Tolerance |
SEMI JEIDA |
15.88 17.50 |
20.00 | 22.22 22.00 |
22.00 | 27.00 27.00 |
32.50 32.50 |
42.50 42.50 |
57.50 47.50 |
57.50 57.50 |
|
| SEMI JEIDA |
1.65 2.50 |
2.50 | 3.17 2.50 |
3.00 | 3.00 2.50 |
2.50 2.50 |
2.50 2.50 |
2.50 2.50 |
2.50 2.50 |
|||
| SECONDARY FLAT LENGTH | Dimension Tolerance |
SEMI JEIDA |
8.00 - |
11.18 - |
11.50 - |
13.50 - |
18.00 - |
27.50 - |
37.50 - |
NO 2nd flat - |
||
| SEMI JEIDA |
1.65 - |
1.52 - |
1.50 - |
1.50 - |
2.00 - |
2.50 - |
2.50 - |
- - |
||||
| BOW MAX | Dimension | SEMI JEIDA |
0.038 | 0.040 | 0.040 | 0.040 | 0.040 | 0.040 | 0.060 | 0.065 | ||
| TOTAL THICKNESS VARIATION | Dimension | SEMI JEIDA |
0.012 0.015 |
0.020 | 0.025 0.025 |
0.025 | 0.025 0.025 |
0.010 0.025 |
0.010 0.025 |
0.010 0.025 |
0.010 0.025 |
|
| EDGE PROFILE COODINATE；Cy | Dimension | SEMI JEIDA |
0.093 | 0.127 | 0.133 | 0.158 | 0.175 | 0.208 | 0.208 | 0.225 | 0.242 | |
Why do the Japanese use Jeida Flats Instead of the Flat Lengths in the United States?
The difference in flat lengths between the JEIDA (Japan Electronic Industry Development Association) standard and the SEMI (Semiconductor Equipment and Materials International) standard in the United States primarily comes down to historical industry practices and regional standardization efforts.
Reasons for JEIDA Flats in Japan vs. SEMI Flats in the U.S.:
-
Historical Development
- The Japanese semiconductor industry developed independently in the mid-to-late 20th century and established its own wafer specifications through JEIDA.
- Meanwhile, the U.S. and other Western countries followed SEMI standards.
-
Identification and Automation Differences
- Wafer flats are primarily used for orientation and doping identification.
- JEIDA and SEMI standards assign different flat lengths to represent wafer crystallographic orientation and doping type, leading to regional differences in how wafers are processed and handled.
-
Industry Standardization
- Japan adopted JEIDA flats for consistency in manufacturing and automation within the country.
- The U.S. and Europe followed SEMI standards to align with equipment manufacturers and global suppliers.
-
Transition to Notch-Based Wafers
- The industry has largely shifted to notch-based wafers (especially for 200 mm and 300 mm wafers), making the difference between JEIDA and SEMI flats less relevant today.
- Flats are still seen in smaller wafers (≤150 mm) and certain legacy processes.
Comparison of JEIDA vs. SEMI Flats
| Wafer Diameter | JEIDA Flat Lengths (Japan) | SEMI Flat Lengths (U.S.) |
|---|---|---|
| 2-inch (50 mm) | 16 mm | 19 mm |
| 3-inch (75 mm) | 22 mm | 22 mm |
| 4-inch (100 mm) | 32 mm | 32 mm |
| 5-inch (125 mm) | 42 mm | 47.5 mm |
| 6-inch (150 mm) | 57 mm | 57.5 mm |
| 8-inch (200 mm) | Notch | Notch |
Would you like more details on specific wafer sizes or how these standards impact your sourcing?