Thin film deposition is the application of a film to the primary substrate material of a semiconductor. This film can be made of a variety of materials, such as insulating compound silica, semiconductor polysilicon, copper metal, etc. The equipment used for coating is called thin film deposition equipment. Thin film preparation processes can be divided into two categories according to their film-forming methods: physical vapor deposition (PVD) and chemical vapor deposition (CVD), of which CVD process equipment accounts for a higher proportion.
Chemical vapor deposition (CVD) is the process of using gaseous or vapor substances to react on the gaseous phase or gas-solid interface to form solid deposits.
The chemical vapor deposition process is divided into three important stages: the diffusion of the reactive gas to the surface of the matrix, the adsorption of the reactive gas on the surface of the matrix, the chemical reaction on the surface of the matrix to form a solid deposit, and the resulting gaseous by-products from the surface of the matrix. The most common chemical vapor deposition reactions are: thermal decomposition reaction, chemical synthesis reaction and chemical transport reaction.
In the semiconductor CVD process, one or more precursor gases are typically used, which are chemically reacted in a reaction chamber to produce a solid thin film material, which is then deposited on the surface of the semiconductor wafer. The CVD process can be achieved in different ways such as thermal CVD, plasma CVD, metal-organic CVD, etc.
Common gases include: silica precursor gas (such as silica ether, chlorosilane), nitrogen, ammonia, silicon source gas (such as trimethylsilane, trichlorosilane), hydrogen, etc. For different precursor gases, the flow rate needs to be precisely controlled to ensure the accuracy and stability of the reaction.
For example, in a typical MOCVD setup, a liquid metal-organic precursor located in a separate solution chamber is gently heated as needed, sprayed or bubbled to dissolve the precursor gas, and delivered to the MOCVD reactor via a flow controller via a high-purity carrier gas (typically nitrogen or hydrogen). Controlled flash evaporator. The temperature of this transfer line is precisely controlled to avoid condensation or premature reaction of the precursors before they are introduced into the MOCVD reactor. The precursor flows with a high-purity reactive gas through a special orifice manifold designed to provide uniform deposition and thickness on a heated substrate.
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Importance of MFC Mass Flow Controllers in CVD Equipment:
MFC (Mass Flow Controller) is widely used to control and monitor the flow of various gases. Among the applications in CVD:
Flow control: MFC is essential for the operation of CVD equipment. It is able to precisely measure and regulate the flow into the reaction chamber to ensure an accurate supply of reaction gases. This is essential to control film thickness and avoid film inhomogeneity due to flow changes.
Stability Monitoring: MFC can monitor fluid flow changes in real time, thus ensuring the stability and consistency of the CVD process. This monitoring helps to identify and resolve equipment failures and maintain equipment performance in a timely manner.
Program control: MFC can control the flow change of the fluid through preset programs, so as to realize the automation and programming of the CVD process. This helps to increase productivity and reduce human error.
The following is a series of high-precision, wide-range optional flow MFC2000 controllers from SIARGO in the United States, which is the agent of ISWEEK. The MFC2000 Series mass flow controllers feature the company's proprietary MEMS Thermal-D operating "" thermal sensing technology with intelligent control electronics, a unique mass flow sensing technology that eliminates gas susceptibility for some gases with similar diffusivity and allows for gas identification after programming. This product can be controlled with a dry dynamic range of 100:1 with a pressure range of 0.1 to 0.8 MPa (15 to 120 PSL) and a compensation temperature of 0 to 50°C. Volumes from 50 mL/min to 200 L/min are available with digital RS485 Modbus communication and analogue output.
The product is designed for easy replacement of mechanical connectors, with dual ferrules, VCR, or UNF options for standard connectors, and other custom connectors available upon request. SIARGO's MFC2000 flow controllers play an important role in CVD equipment, which can accurately measure and control the size of gases, and can achieve high-temperature, high-precision, high-resolution thin film deposition processes.