An Important Component Affecting the Yield of Semiconductor Products—Quartz Products
Quartz plays a crucial role in the semiconductor production processes, with its quality and processing precision directly impacting the yield of semiconductor products. Typical applications of quartz materials in semiconductor production include the use of quartz crucibles for silicon single crystal manufacturing, quartz glass bell jars for lithography engineering, and quartz holders and quartz boats made from quartz tubes for IC epitaxy, diffusion, and lithography engineering.
The quartz crucible represents the primary product derived from high-purity quartz sand in the photovoltaic and semiconductor industries. It is mainly employed to facilitate continuous crystal pulling under high temperatures and serves as a consumable quartz container for the polysilicon raw materials. Quartz crucibles can be classified into two main categories: square crucibles and round crucibles. Square quartz crucibles are employed in the casting of polysilicon ingots, whereas round quartz crucibles are utilized in the drawing of single crystal silicon rod.
Quartz crucibles are characterized by a high degree of cleanliness, homogeneity and resistance to high temperatures. In terms of physical thermal properties, the quartz crucible demonstrates a deformation point at approximately 1100℃ and a softening point at about 1730℃. It can be continuously used at a high temperature about 1100℃, and the maximum temperature for short time use can reach 1450℃. The high purity and exceptional temperature durability of the quartz crucible provide assurance for the drawing of single crystal silicon rod and the quality of single crystal, making it an essential component in the single crystal drawing system.
In the manufacturing process of single crystalline silicon wafers, the quartz crucible is the key component of the photovoltaic single crystal furnace. Due to the strict requirements for purity of single crystalline silicon wafers, the quartz crucible must be discarded after one to several uses for heating and pulling crystal, and a new quartz crucible needs to be purchased for the next crystal pulling, making it a consumable product in the single crystalline silicon industry chain.
In the semiconductor IC manufacturing process, it is frequently necessary to utilize a tool for the transfer, cleaning and processing of chips. The apparatus that conveys the chips is typically called a wafer boat, which is set up with a number of wafer slots, with each wafer slot being used to place a wafer. In the manufacturing process of semiconductor wafers, the diffusion process of the furnace tube is one of the basic processes. In the diffusion process, multiple wafers are initially placed on a quartz wafer boat, which is then placed in the furnace tube for batch manufacturing. In addition, a quartz holder is a device employed to carry multiple quartz boats.
The manufacture of silicon transistors and integrated circuits entails the the silicon chip cleaning in almost every stage of production, and the quality of silicon chip cleaning has a significant impact on the performance of the device. Among them, chemical cleaning is employed to remove the invisible pollution of atoms and ions, which can be achieved by various methods, such as solvent extraction, pickling (sulfuric acid, nitric acid, aqua regia, various mixed acids, etc.) and plasma method; Whereas, ultrasonic cleaning (physical cleaning), relying on air corrosion, can effectively remove the pollution on the wafers by transferring ultrasonic energy into the solution.
In the cleaning process, it is essential to utilize acid-resistant and alkali-resistant quartz apparatus. Among these, the quartz basket is responsible for carrying the silicon wafer, while the quartz cleaning tank is responsible for carrying the washing.
The etching process is a highly intricate and crucial semiconductor procedure, serving as a primary technique for pattern processing related to lithography, and the quartz flanges are applied for that. “Lithography” refers to the lithographic exposure of the photoresist (equivalent to using a projection to “draw” the circuit diagram on the wafer). “Etching” involves patterning the photoresist surface, using chemical or physical methods to selectively remove material from the silicon wafer’s surface, thereby engraving the circuit diagram onto it.
In this process, the high-purity quartz flange serves a principal protective function, and the combination of the flange and the quartz gate can achieve the sealing and protection of the cavity. They are in close contact with the wafer to prevent the ingress of all kinds of pollution during the etching process.
In semiconductor processing, a large number of quartz products need to be used. According to the different working temperatures, it can be divided into two categories: high-temperature processes and low-temperature processes. High-temperature processes include diffusion, oxidation, etc., low-temperature processes include etching, packaging, lithography, cleaning, etc.
The rapid development of the electronics industry has increased the demand for high-performance quartz glass products in the semiconductor industry, directly propelling rapid advancements in high-performance quartz glass product development.
