Semiconductor silicon wafer introduction and main types
① Introduction to semiconductor silicon wafers
Silicon is one of the common semiconductor materials.Silicon element is about in the crust is about 27%, second only to oxygen.Silicon elements exist in the form of silicon dioxide and silicate in the form of sand, rocks, and minerals, which are rich in reserves and easy to obtain.Silicon dioxide has become polysilicon after chemical purification.The polysilicon can be divided into metallurgical, solar energy and semiconductor grades according to its purity from low to high.
Among them, semiconductor -grade polysilicon has the highest silicon content, and generally requires 9N to 11N is the basic raw material for the production of semiconductor silicon wafers.The semiconductor -grade polysilicon grows through the crystal of the single crystal furnace to generate single crystal silicon rods. This process is called crystal growth.Semiconductor silicon wafer refers to a thin piece cut from a single crystal silicon rod.Subsequent processing such as lithography, etching, and ion injection on the downstream.
② The main category of semiconductor silicon wafers
Semiconductor silicon wafers can usually be classified according to size and process.
Classification by size of semiconductor silicon wafers
The size of the semiconductor silicon wafer (calculated in diameter) is mainly available 2 -inch (50mm), 3 inches (75mm), 4 -inch (100mm), 5 -inch (125mm), 6 inches (150mm), 8 inches (200mm) and 12 -inch (300mm), etc.Continuously develop in a large size.
On the one hand, the larger the size of the silicon wafer, the more the number of chips made on single -piece silicon wafers, and the cost of unit chips decreases.On the other hand, the larger the size of the silicon wafer, the smaller the loss that the edge of the rectangular chip created on the circular silicon wafer will not be used, which will help further reduce the cost of the chip.
by For example, 12 -inch and 8 -inch semiconductor silicon wafers are examples. The area of 12 -inch semiconductor silicon wafers is 2.25 times the area of 8 -inch semiconductor silicon wafer area, but under the same process conditions, the 12 -inch semiconductor silicon wafer can be available.The indicator of the number of chips that can be produced) is about 2.5 times the 8 -inch semiconductor silicon wafer.
From After the 12 -inch semiconductor silicon wafers have been successfully developed, due to the large -scale investment and research and development costs that continue to expand, the semiconductor silicon wafer industry has not yet developed to a larger size.At present, the mainstream products of the global market are 8 -inch and 12 -inch semiconductor silicon wafers.The larger the size of the semiconductor silicon wafer, the greater the investment scale of the corresponding semiconductor silicon wafer production line, and the higher the requirements for the production technology, equipment, materials, and technology of semiconductor silicon wafers.
Judging from the application field adapted in the downstream,The demand of 8 -inch and below semiconductor silicon wafers mainly comes from power device, power manager, non -easy -to -loss memory, MEMS, display driver chip and fingerprint recognition chip.Industrial electronics, etc.; The demand for 12 -inch semiconductor silicon wafers mainly comes from storage chips, image processing chips, universal processor chips, high -performance FPGA (on -site programming door array) and ASIC (dedicated integrated circuit). The terminal application is mainly smartphones, Computers, cloud computing, artificial intelligence, SSD (solid storage hard disk) and other high -end application areas.
Classified by manufacturing process
According to the manufacturing process classification, semiconductor silicon wafers can be divided into polishing, extension, and SOI silicon wafer.The single crystal silicon ingot is cut, grinding, and polishing, and the polishing film is obtained. The polished film is a single -sided or double -sided silicon wafer.With the development of a more advanced and more refined direction in the integrated circuit system, the depth of the landscape of the lithography machine is getting smaller and smaller. The extremely small height difference on the silicon wafers will deform and misalcer the integrated circuit wiring diagram.The surface flatness puts forward harsh requirements.
In addition, the surface particle size and cleanliness of the silicon wafer also directly affect the yield of semiconductor products.The polishing process can remove the damage layer of the processed surface residue, realize the flat surface of semiconductor silicon wafers, and further reduce the surface roughness of the silicon wafer to meet the requirements of the flatness and surface particles of the silicon wafer manufacturing process.
Practice can be used directly to make semiconductor devices, or it can also be used as an outer delay and SOI silicon wafer substrate material.Depending on the doping concentrations of boron, phosphorus, arsenic, and crickets in semiconductor silicon wafers, the semiconductor polishing tablets can also be further divided into light doped polishing slices and heavy polishing sheets. The more doped, the lower the resistivity.Light mixing fillets are mainly used in the field of integrated circuits, and heavy -doping polishing pieces are mainly used in the fields of power devices.
Under the subsequent extension of the subsequent extension, the downstream application is usually used, and the light -doping film can usually be directly used in downstream applications. Therefore, the technical difficulty of light doping film and higher requirements for product quality.The polishing film has been extended to form an external delay.The extension is a new silicon single -crystal layer that grows a layer of a specific doping type, resistivity, thickness and lattice structure through a layer or multi -layer with chemical gas deposition.Extension technology can reduce the defects caused by crystal growth in the silicon wafer, and have lower defect density and oxygen content.
Outer slices are often in Use in the CMOS circuit, such as universal processor chips, graphics processor chips, etc., because the oxygen content, carbon content, and defect density of the extension sheet is lower than the polishing sheet.The leakage phenomenon in the road has improved the reliability of the integrated circuit.
In addition, the extension of a layer of high resistivity is usually extended on the silicon base with a low resistance rate of low resistance rate, which is applied to the diode,Manufacturing of power devices such as IGBT (insulation grid bipolar transistor).Power devices are commonly used in high -power and high -voltage environments. The low resistivity of the silicon substrate can reduce the pitch resistance, and the extension layer of the high resistivity can increase the penetrating voltage of the device.The extension of the outer pads has improved the reliability of the device and reduced the energy consumption of the device. Therefore, it is widely used in industrial electronics and automotive electronics.
SOI silicon wafers, that is, insulated silicon, is one of the common silicon -based materials. Its core feature is to introduce a layer of oxide insulating layer between the top -layer silicon and the support base.SOI silicon wafers are suitable for applications that require high -voltage, harsh environment, low power consumption, and high integration chips, such as radio frequency front -end chips, power devices, sensors, and silicon photon devices.
（2) The development of semiconductor silicon wafers industry
① global semiconductor silica wafer industry chain
Semiconductor silicon wafers are the core key materials of chip manufacturing, and it accounts for relatively high costs in chip manufacturing materials.The downstream customers of semiconductor silicon wafers are chip manufacturing companies, including wafer founders and idm manufacturer.Lower industry application coverage computing, wireless communication, consumer electronics, automotive electronics, industrial electronics, storage and wired communication, etc.
② Industry competition pattern and development trend
The market concentration of the semiconductor silicon wafers industry is relatively high. Due to the high technical difficulty of the semiconductor silicon film industry, the long R & D cycle, and the long customer certification cycle, a few companies that have taken the lead in grasping advanced technologies occupy most of the market share.
Although the current international leading semiconductor silicon manufacturer has a high market share, with the active expansion of mainland semiconductor silicon wafers in mainland China, the market share is rapidly increasing.In addition, mainland China is becoming an important destination for the third expansion of global semiconductor capacity.With the lack of layers in the wafer plant, Mainland China wafer fab, SMIC, Huahong Semiconductor, Taiwan's WAils in Taiwan, TSMC, Lianhua Electronics Co., Ltd. and other wafers in mainland ChinaTo accelerate the development and layout of the domestic semiconductor industry, mainland Chinese semiconductor silicon wafers will also get unprecedented development opportunities.
③ The market situation and development trend of all sizes of semiconductor silicon wafers worldwide
The most mainstream product specifications of the global semiconductor silicon wafer market are 12 -inch silicon wafers and 8 -inch silicon wafers, the area of 8 -inch silicon wafers remains relatively stable, and the area of 12 -inch silicon wafers has remained fluctuating.Since 2011, the demand for 6 -inch and below small -sized silicon wafers has continued to exist, but due to the influence of unfavorable factors such as technological upgrades and increasing supply of large -sized silicon wafers, the shipments of small -sized silicon wafers below have basically maintained the relative relative.Stable level.
In recent years,The market share of 12 -inch silicon wafers and 8 -inch silicon wafers continued to remain at a very high level. In 2021, 68.47%and 24.56%, respectively. The total proportion of two sizes of silicon wafers maintained more than 90%.The main size of market demand.With the increase in the area of global semiconductor silicon wafers, the market share of 6 inches and below small -sized silicon wafers has declined, and by 2021, it is about 6.97%of the global semiconductor silicon wafer shipment area.