Semiconductor Wafer Production Process

Semiconductor Wafer Production Process – Cheersonic

The production process of semiconductor silicon wafers is long and involves many processes. The production process of semiconductor polishing wafers includes crystal pulling, spheronization, cutting, grinding, etching, polishing, cleaning and other processes; the production process of semiconductor epitaxial wafers is mainly epitaxial growth on the basis of polishing wafers; SOI silicon wafers mainly use bonding or ionization injection, etc. Every process link of a semiconductor silicon wafer will affect the quality, performance and reliability of the finished product.

According to the classification of manufacturing process, semiconductor silicon wafers can be mainly divided into polished wafers, epitaxial wafers and high-end silicon-based materials represented by SOI wafers. The single crystal silicon ingot is cut, ground and polished to obtain a polished sheet. The polished wafer is epitaxially grown to form an epitaxial wafer, and the polished wafer is processed by oxidation, bonding or ion implantation to form an SOI silicon wafer. With the continuous reduction of the feature line width of the integrated circuit, the depth of field of the lithography machine is also getting smaller and smaller, and the extremely small height difference on the silicon wafer will cause the integrated circuit wiring diagram to be deformed and dislocated. demanding requirements.

In addition, the surface particle size and cleanliness of silicon wafers also have a direct impact on the yield of semiconductor products. The polishing process can remove the residual damage layer on the machined surface, realize the planarization of the surface of the semiconductor silicon wafer, and further reduce the surface roughness of the silicon wafer to meet the requirements of the chip manufacturing process for the flatness and surface particle size of the silicon wafer. Polished wafers can be directly used to make semiconductor devices, widely used in memory chips and power devices, etc., and can also be used as substrate materials for epitaxial wafers and SOI silicon wafers. Epitaxy is the growth of one or more layers on the polished surface by chemical vapor deposition. The doping type, resistivity, thickness and lattice structure of a new silicon single crystal layer meet the requirements of a specific device. Epitaxy can reduce defects in silicon wafers due to single crystal growth, with lower defect density and oxygen content.

Epitaxial wafers are often used in CMOS circuits, such as general-purpose processor chips, graphics processor chips, etc. Compared with polished wafers, epitaxial wafers contain lower oxygen, carbon, and defect density, which improves the integrity of the gate oxide layer. , improving the leakage phenomenon in the channel, thereby improving the reliability of the integrated circuit. In addition, a high-resistivity epitaxial layer is usually epitaxially grown on a low-resistivity silicon substrate, which is used in the manufacture of power devices such as diodes and IGBTs (insulated gate bipolar transistors). Power devices are often used in high-power and high-voltage environments. The low resistivity of the silicon substrate can reduce the on-resistance, and the epitaxial layer with high resistivity can improve the breakdown voltage of the device.

Epitaxial wafers improve the reliability of the device and reduce the energy consumption of the device, so they are widely used in industrial electronics, automotive electronics and other fields. SOI silicon wafer is silicon-on-insulator, which is one of the common silicon-based materials. Its core feature is that an oxide insulating buried layer is introduced between the top silicon and the supporting substrate. The specific process is as follows:
1. Crystal pulling process: polysilicon, melting, access to seed crystal, rotary crystal pulling, single crystal silicon ingot
2. Silicon ingot processing: silicon ingot deheading, radial spheronization, positioning edge/slot grinding, silicon ingot grinding
3. Forming process: slicing, double-sided grinding, chamfering, etching
4. Polishing link: double-sided polishing, edge polishing, final polishing, polishing sheet
5. Epitaxy: epitaxial growth, epitaxial wafer
6. Cleaning and shipping links: polishing wafers/epitaxial wafers, cleaning, testing, packaging, and shipping

Cheersonic is the leading developer and manufacturer of ultrasonic coating systems for applying precise, thin film coatings to protect, strengthen or smooth surfaces on parts and components for the microelectronics/electronics, alternative energy, medical and industrial markets, including specialized glass applications in construction and automotive.