A wafer is a thin piece of a semiconductor substance, such as crystalline silicon, used in electronics to make integrated circuits. In electronic jargon, a thin piece of semiconductor material is called a wafer. It can be a silicon crystal that is used to make integrated circuits and other microdevices.
The wafers are made of a very pure monocrystalline material. In the Czochralski process, a cylindrical ingot of a highly pure monocrystalline semiconductor such as silicon or germanium is produced by drawing a seed crystal from an alloy. The donor impurity atoms are added to the internal molten material in precise amounts to ensure doping of the crystal. Thus changing the semiconductor to an n or p type semiconductor. The ingot is then sliced to form wafers. They require a semiconductor grinding process.
The silicone plates are available in various sizes, in this case with diameters. They are available from 25.4mm to 450mm. Semiconductor plants are known for the diameter of the wafers they produce. The diameter of the plates has increased to keep costs down, with the current generation of factories being 300mm in diameter.
The wafers grown using materials other than silicone will have a different thickness than the silicone wafers. The thickness of the tile is measured by the mechanical strength of the material used. The thickness of the plate must be sufficient to support its own weight during handling.
Wafers with a diameter of less than 200 mm are cut into flat bars on one or more sides. Which indicates the crystallographic planes of the wafer. The earlier generation of tiles had a pair of flat bars positioned at different angles which additionally reflected a kind of doping. 200 mm wafers use a single small notch to convey wafer orientation which does not provide a visual indication of the type of admixture used.
Here are 10 important facts you need to know about semiconductor wafers:
1. Semiconductor wafers are made of silicon, which is the second most abundant element on Earth (after oxygen) and the seventh most abundant element in the entire universe.
2. Since the sand used to make semiconductor wafers must be very clean, most of the sand used for these processes is shipped from Australian beaches. For the production of semiconductor wafers, you can use not only sand scraped off the beach.
3. Semiconductor wafers are available in various diameters. In 1960, the US produced the first semiconductor wafer, a semiconductor wafer diameters was 1 inch. Currently, the standard wafer size is 12 inches with a predictable plan to get 18 inch wafers.
4. The wafers are formed from a very clean, almost defect-free single-crystal material. The process of forming these conductors is called Czochralski. During this process, silicon or germanium is produced by drawing the seed crystal out of the alloy. Boron or phosphorus may be added to the custom melt in direct amounts to dope the crystal. After the crystal is doped, the material is then converted into an external n and p type semiconductor.
5. The wafer thickness will vary greatly. The thickness of the wafer is always determined by the mechanical strength of whatever material is used to make it. No matter what the semiconductor is made of, the wafer must be thick enough to support its own weight so that it does not break during the handling process.
6. The use of an extrinsic (pure) semiconductor wafer can be seen in many everyday electrical devices. An extrinsic semiconductor is a semiconductor that has been doped and is transformed into a pure semiconductor. Applications such as Laser, Solar Cells are based on the extrinsic semiconductor.
7. Even though silicon is considered to be the most prevalent material for wafers that are used in electronics, other compounds can be used as well. III-V or II-VI materials have also been used. Gallium arsenide or (GaAs) is an IIIV semiconductor that is produced during the Czochralski process. It’s often used as a common wafer material.
8. Die per wafer calculation is the first step for every engineer that wishes to find out the price of each die on a semiconductor wafer. Gross number of dies per wafer can easily and quickly be calculated using the software.
9. In some specific applications, the die per wafer is equal to 1 (one) which means that there is a single die on each semiconductor wafer. As the maskset reticle cannot cover the entire semiconductor wafer, a special stitching needs to be performed to connect the different tiles together. Some silicon wafer suppliers have very good experience in these types of applications.
10. Proper storage conditions are necessary to prevent contamination and/or degradation after shipment. Semiconductor Wafers that are not vacuum sealed must be placed in a Nitrogen (N2) cabinet with a flow rate of 2 to 6 SCFH (Standard Cubic Feet per Hour).
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