Wafer is one of the important contemporary equipment, usually familiar with the wafer, electronics and other related professions.wafer testing In order to improve our understanding of wafers, this article will introduce the difference between wafers and silicon. If you are interested in wafers, you can continue reading.

I. Wafer

(I) Concept

Wafer refers to the silicon semiconductor integrated circuits made of silicon, because of the round shape and is called a wafer; can be processed into a variety of circuit element structure, to become an IC product with a specific electrical function. The raw material for wafers is silicon, the useful silicon dioxide on the surface of the earth's crust.

(ii) The manufacturing process of wafers

Wafers are the basic structural materials for manufacturing semiconductor chips, semiconductor integrated system circuits,wafer probe including the main raw material is silicon, so the enterprise corresponds to silicon wafers.

Silicon occurs naturally in rocks and boulders in the form of silicates or silicon dioxide. The production of silicon wafers can be divided into three basic steps: the extraction and purification of silicon, the growth of single crystal silicon, and the formation of silicon wafers.

First is the purification of silicon, that is, the gravel raw materials into the carbon source of the electric arc furnace, the temperature of about 2000 ℃, carbon at high temperatures and gravel in the reaction of silicon dioxide (carbon and oxygen combination, leaving silicon). The purity of about 98% pure silicon, also called metallurgical silicon, is not pure enough for microelectronic equipment. Since the electrical properties of semiconductor materials are very sensitive to the concentration of impurities, metallurgical silicon is further purified: metallurgical silicon is broken up and reacts with gaseous hydrogen chloride to produce liquid silane.

Next is the growth of monocrystalline silicon wafers, the most common method of which is straight drawing. The high-purity polysilicon is placed in a quartz crucible and surrounded by graphite heaters that continuously heat it. The air inside the furnace at a temperature of around 1400 °C is usually inert, and the polysilicon melts without unwanted chemical reactions. The orientation of the crystals is also controlled in order to form single crystal wafers: The crucible rotates with the polysilicon melt, the seed crystals are immersed in it, and the pulling rods rotate with the seed crystals in the opposite direction and then slowly, vertically, pull them out of the silicon melt. The molten polysilicon adheres to the bottom of the seed crystals and continues to grow in the direction in which the seed crystals are aligned. Thus, the orientation of the crystals is determined by the seed crystals, and after pulling and cooling, the single crystal silicon rods grow in the same direction as the lattice in the seed crystals. After growth by the tirage method, the single crystal rods are cut to the proper size, then ground to remove dents, and then chemically and mechanically flattened to make at least one side as smooth as a mirror for wafer fabrication.

The diameter of a single crystal rod is determined by the lifting speed and rotation speed of the seed crystal.probe holder In general, the slower the lifting speed, the larger the diameter of the monocrystalline silicon bar. The thickness of the cut wafer is related to the diameter. Although the preparation of semiconductor devices is only done within a few microns of the top of the wafer, the thickness of the wafer is typically 1 mm, and the thickness of the wafer increases with diameter in order to ensure adequate mechanical stress support.

Wafer manufacturers melt these impact polysilicon, and then planted seed crystals in solution, and then we slowly pull out to form a cylindrical single crystal silicon rods, because the silicon rods are in the molten silicon raw materials to study the gradual development of the crystalline structure generated by the surface of the seed crystals carried out to determine the process of work is known as the long crystals. Silicon crystal rods after continuous cutting, grinding, cutting, chamfering, polishing, laser engraving, packaging, and then become the basic raw material for the production of China's integrated system circuit design factories - silicon wafers, or wafers.

(iii) Basic raw materials for wafers

Silicon is refined from quartz sand, and wafers are made from pure silicon (99.999%) and then made into silicon rods, a quartz semiconductor material used in the manufacture of integrated circuits. After photocopying, grinding, polishing, slicing and other processes, polycrystalline silicon melted out of monocrystalline silicon rods, cut into thin slices.

II. Silicon Wafers

(A) Definition

Silicon wafer is the raw material for manufacturing transistors and integrated circuits. It is usually monocrystalline silicon wafers. Silicon wafers are an important material for the manufacture of integrated circuits, and various semiconductor devices are manufactured by photolithography and ion implantation. Chips made from silicon wafers have amazing computing power. Advances in science and technology continue to drive the development of semiconductors. Advances in automation and computer technology have reduced the cost of silicon wafers (integrated circuits).

(ii) Specifications of silicon wafers

There are many ways to categorize the specifications of silicon wafers, which can be classified according to parameters such as wafer diameter, single-crystal growth method, doping type, etc. and usage.

1. Divided by wafer diameter

Silicon wafer diameter is mainly 3 inches, 4 inches, 6 inches, 8 inches, 12 inches (300 inches) mm, and now has developed to 18 inches (450 inches) mm) and other specifications. The larger the diameter, through a process cycle in the silicon chip can produce more integrated circuit chips, the lower the cost of each chip. Therefore, large diameter