Semiconductor materials – large-scale silicon wafers
Semiconductor materials are divided into wafer fabrication materials and packaging materials. Wafer fabrication materials can be further subdivided into silicon wafers and silicon-based materials, photomasks, electron gases, photoresists, photoresist assist materials, CMP polishing materials, process chemicals, targets, and other materials.
The packaging materials can be further subdivided into packaging substrates, lead frames, bonding wires, encapsulation materials, ceramic substrates, die attach materials and other packaging materials.
Overall, the market segment of semiconductor materials is scattered and small in scale. Only silicon wafers account for nearly 35% of the market share. Silicon wafers occupy the absolute mainstream of the semiconductor material market, followed by electronic gases accounting for 13%, photomasks accounting for 12%.
The remaining photoresist supporting chemicals, polishing materials, photoresist, wet chemicals, sputtering targets and other materials account for less than 10%, and the scale is relatively small.
The third generation of semiconductors: wide-bandgap semiconductor materials represented by gallium nitride (GaN), silicon carbide (SiC), and zinc oxide (ZnO). It has excellent properties such as high breakdown electric field, high thermal conductivity, high electron saturation rate and strong radiation resistance, and is more suitable for making high-temperature, high-frequency, radiation-resistant and high-power electronic devices.
It has broad application prospects in semiconductor lighting, new generation mobile communications, energy Internet, high-speed rail transit, new energy vehicles, consumer electronics and other fields.
The fourth generation of semiconductors: ultra-wide band gap semiconductor materials represented by gallium oxide (Ga2O3), diamond (C), aluminum nitride (AlN), and ultra-narrow band gap semiconductor materials represented by antimonide (GaSb, InSb) .
Ultra-wide band gap materials have more prominent characteristic advantages in the field of high-frequency power devices due to their wider band gaps than third-generation semiconductor materials; Ultra-narrow band gap materials are mainly used in detectors, lasers and other devices due to their easy excitation and high mobility.
Semiconductor Silicon Wafer is the basis for manufacturing silicon semiconductor products and can be classified according to different parameters.
According to the size (diameter), semiconductor silicon wafers can be divided into 2 inches (50mm), 3 inches (75mm), 4 inches (100mm), 5 inches (125mm), 6 inches (150mm), 8 inches (200mm), 12 inches(300mm).
Under the influence of Moore’s Law, semiconductor silicon wafers are constantly developing in the direction of large size. At present, 8-inch and 12-inch are mainstream products, accounting for more than 90% of the total shipment area.
According to the degree of doping, semiconductor silicon wafers can be divided into lightly doped and heavily doped. Heavy-doped silicon wafers have a large amount of doping elements and low resistivity, and are generally used in power devices and other products;
Lightly doped silicon wafers have low doping concentration and are generally used in the field of integrated circuits, with higher technical difficulty and product quality requirements. Since integrated circuits account for more than 80% of the global semiconductor market, there is a greater global demand for lightly doped silicon wafers.
According to the process, semiconductor silicon wafers can be divided into grinding wafers, polishing wafers, special wafer epitaxial wafers based on polishing wafers, SOI, etc.
Grinding sheets can be used to manufacture discrete devices; lightly doped polishing sheets can be used to manufacture large scale integrated circuits or as substrate materials for epitaxial wafers, and heavily doped polishing sheets are generally used as substrate materials for epitaxial wafers. Compared with abrasive sheets, polishing sheets have better surface flatness and cleanliness.
The semiconductor wafer industry is also a capital-intensive industry, which needs to reach a certain sales scale to be profitable: Large-scale production of semiconductor silicon wafers requires a large investment amount.
Due to the large investment in fixed assets in the early stage, semiconductor wafer companies need to form a certain scale of sales before they can make profits. The operating pressure in the early stage is relatively large, and the gross profit rate may be negative.
At present, the use of silicon wafers by downstream chip companies: discrete devices continue to use small sizes, and integrated circuits migrate to large sizes.
Due to the low price of discrete devices, manufacturers are not motivated to invest in large-scale production lines. At present, silicon wafers of 6 inches and below are still the main products.
The economic benefits brought by the use of large-size silicon wafers in integrated circuits are obvious.
For example, the area of a 12-inch silicon wafer is 2.25 times that of an 8-inch wafer, and the usable rate is about 2.5 times that of an 8-inch wafer. The number of chips that can be produced on a single chip increases, and the cost of a single chip decreases.
Driven by new demands such as telecommuting, online meetings, autonomous driving, and the Metaverse, the demand for 12-inch semiconductor silicon wafers will continue to increase.