Process Of Silicon Wafer Manufacturing
Mostly people are unaware of the term silicon wafer, but this type of device is most common in the fields of information technology, chemistry, and physics and known to professionals such as chemists and physicists. The manufacturing of silicon wafer is an interesting process.
Basically this device is a circular, thin disc used in the manufacturing of semiconductors and integrated circuits. Other types like Gallium Arsenide and SOI are silicon insulator. They are used in electronics, which requires careful and accurate manufacturing to ensure high levels of efficiency. Several important steps are to be followed before preceding the manufacturing. Due to its capacity to conduct both heat and electricity in a way that is very controlled it can become the efficient material in the electronic sphere by just undergoing processes such as fabrication and photolithography.
The electrical properties of silicon can be manipulated by adding the other elements called “dopants” which determine the type of silicon either negative or positive, and change the resistivity of silicon to make it more conductive. The type of dopant determines the final wafer, whether the wafer is an N-Type or a P-Type. And the amount of dopant determines its final resistivity. P-Type silicon wafers are very common in terms of sales volume and production. These types of wafers are formed with only one type of dopant called boron. Amount of boron in the silicon wafer determines its resistivity; the less boron the more will be the resistivity while the more boron the lower resistivity. The huge abundance of P-Type silicon wafers tends to reduce the costs than the N-Type wafer.
These wafers are used in creating integrated circuits and microchips for microelectronics. Top companies of information technology and electronics use SOI wafers to produce the microprocessors. Solar energy technology is also used to create solar cells with the help of GaAs and silicon. Engineers start the process by designing the circuits and also by defining the essential functions. Special software are used to determine the specifications like signals, outputs, voltages and inputs. It is then exported to the programs which further lay out the designs of the circuits. During this process the layers of silicon wafers are defined.
First of all, a perfect crystal should be produced from silicon then it must be submerged in to a vessel with molten sand. Afterwards the cylinder shaped pure silicon is carefully withdrawn. Then the ingot (cylinder shaped pure silicon) is thinly sliced, using a diamond saw and silicon slices are sorted according to the thickness of each silicon wafer. In the slicing process the defects are being checked by the manufacturers. If the silicon surface of any wafer found damaged or cracked then it is removed using the process called as lapping. To remove crystal damage etching process is used.
Next step is to check the flatness and thickness. During this step defects are checked that occurred in lapping and etching process.
Uneven surfaces need to be polished to create a smooth and flat surface. Specifications of the customer will also be ensured before the final delivery of the product. The price of wafer is determined based on the quality and thickness.
Wafers then exposed to UVB light. The heated chemical vapors are then deposited on the required areas and are baked. The process is repeated several times. The resolution of the surface is increased during each step. The technology is changing rapidly and with the new technology comes denser packing of the features.
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ABOUT THE AUTHOR
I belong from the semiconductor manufacturing field. And I have vast knowledge about different types of silicon wafers such as P-type silicon wafers or N-Type silicon wafers.