The crystal structure of silicon (Si) is a diamond-type structure.
|Melting point||1414℃||Thermal expansion||20℃ 2.6µm/(m･K)|
|Boiling point||3265℃||Mohs hardness||7|
|Crystal structure||Cubic||Band gap||0℃ 1.206eV|
|Thermal conductivity||0℃ 168W/(m･K)|
Silicone is a similar material to silicon. Silicone is an artificial compound made from silicon. It is silicone that is contained in shampoos, not silicon.
Silicon is a type of metal. Its elemental symbol is “Si”. Currently, silicon is the material most commonly used for semiconductor substrates. Silicon is the second most abundant element on Earth after oxygen, and makes up 26.77% of the Earth’s crust. In its natural state, silicon exists as a compound tightly combined to oxygen (=silicon oxide). In order to use silicon as a semiconductor material, the oxygen must be separated from it and the pure silicon must be extracted.
Silicon is used not only for semiconductor materials but also for lenses in infrared optical systems. Silicon has a high infrared transmittance (wavelength of 2 to 6 μm), and it can be used for various infrared applications including near-infrared imaging and infrared spectrometry by applying precise optical polishing.
Silicon (Si) is used as a material for semiconductor substrates, which are often called silicon wafers. In order to use silicon as a material for semiconductor substrate, the percentage of pure single-crystal silicon (with high purity) must be significantly raised. Silicon wafers are made by forming high-purity silicon into a large and narrow ingot and cutting the ingot into disks. There are some manufacturing processes for silicon ingots, such as the CZ (Czochralski) method and the FZ (floating zone) method.
There are three crystal orientations for silicon (Si) substrates: (100), (110), and (111). Silicon substrate (100) is most commonly used for semiconductor substrate materials. Silicon substrate (110) is used for some of the most advanced memory devices, and silicon substrate (111) is sometimes used as a reference sample for atomic force microscopes (AFM) or scanning tunneling microscopes (STM).
Since a very precise circuit is formed on the surface of the semiconductor substrate material, the surface of the silicon (Si) substrate must be flat. The surface of the silicon (Si) substrate has minute undulations immediately after being cut out from the silicon ingot into a disk, so it is necessary to planarize and thin the silicon (Si) substrate to the designated thickness. For this wafer thinning process, DISCO’s grinders (processing using a grinding wheel) can be used.
Silicon is the second most abundant element on Earth. Most of the semiconductor devices are currently made of silicon because the purification of silicon is easy and large single crystals can be purified. Silicon has a high infrared transmittance (wavelength of 2 to 6 μm), and it can be used for windows or lenses in an infrared optical systems.
DISCO’s dicing saws (cutting equipment using a blade), laser saws (cutting equipment using a laser), and grinders (processing equipment using a grinding wheel) are used in the back-end process of device manufacturing.