Gas distribution system for semiconductor chip factory
With the development of the semiconductor industry, there are more and more integrated circuit chip factories. The investment in the new project of the semiconductor chip factory is huge, and the investment in the plant infrastructure, clean room, bulk gas gas station, special gas cabinet for the main system of the plant, and semiconductor equipment is all necessary. This article will briefly introduce the important gas system construction, which involves many complicated construction, installation and commissioning links. The figure below shows the general composition of the gas distribution system in a chip factory.
Main Composition of gas transmission system in chip factory:
1. Bulk gas system: Storage and pressure control for the inert gas
Line size: from 1 / 4 (monitoring line) to 12 inches
The main products of the main line system are: diaphragm valve / bellows valve / ball valve, high purity joint (VCR, welding form), card sleeve joint, pressure regulating valve, pressure gauge, etc.
The new system also includes a bulk special gas system, which uses fixed gas cylinders or tank trucks for storage and transport.
2. System forpurification: Removing impurities in bulk gas for high purity gas lines
3. Gas Cabinets: Provide pressure control and flow monitoring for special gas sources (toxic, flammable, reactive, corrosive gases), and have the ability to replace gas cylinders
Location: On the Sub-fab floor or the lowest floor
Special gas sources that can be stored: NF3, SF6, WF6, etc.
Line Sizes: Internal gas lines, typically 1/4 in. for process lines, 1/4-3/8 in.
Main products: high-purity diaphragm valves, check valves, pressure gauges, pressure gauges, high-purity connectors (VCR, welded), these gas cabinets basically include the ability to automatically switch cylinders, which can ensure continuous gas supply and safe replacement of cylinders.
4.Distribution：Connect the gas source to the gas aggregate tray line
Dimensions: In the chip factory, the line size range of bulk gas distribution is generally 1 / 2, inch to 2 inch.
Type of attachment: Due to the strong sealing reliability of welded connections, special gas pipelines are generally connected by welding without any mechanical connections or other moving parts
A chip factory needs hundreds of kilometers of ferrule connections to transmit gas. The length of a ferrule is basically about 20 feet. It is very common to connect the ferrule by welding.
5. VMB (Valve Manifold Box)
VMB is a device that distributes special gas from the gas source to different equipment terminals
Line size: 1 / 4 inch process line, and 1 / 4-3 / 8 inch purge line.
System products: high-purity diaphragm valves/bellows valves, check valves, high-purity connectors (VCR, micro-welding), pressure regulators, pressure gauges, pressure gauges, etc. For the distribution of some inert gases, the Valve Manifold Panel - VMP (Valve Manifold Panel) is mainly used. The open gas panel does not require closed space design and additional nitrogen purge.
6. Tool Hookup Panel
It connects the gas required by semiconductor equipment from the gas source to the equipment end, and provides corresponding pressure adjustment. This panel is a gas control system closer to the equipment end than VMB (Valve Manifold Box).
Gas line size: 1 / 4-3 / 8 inch
Liquid line size: 1 / 2-1 inch
Discharge line size: 1 / 2-1 inch
Main products: diaphragm valve/bellows valve, check valve, pressure regulating valve, pressure gauge, pressure gauge, high-purity joint (VCR, micro welding), ferrule joint, ball valve, hose, etc.
The current difficulties of building a new semiconductor chip factory
A large number of high-purity fluid system pipe valve products is necessary to build a new semiconductor chip factory. Due to the huge investment in the chip factory project and the strict control of the construction period, once the project delayed, the loss will be very huge, so the timely supply of products at each stage is very important. General engineering companies often set up special product warehouses at project site in order to pick up products in a timely manner.
Due to the extensive use of various special media (corrosive, toxic, flammable and explosive special gases and various chemicals) in chip factories, sealing reliability is a priority when designing transmission systems for these special media. For example, for the transmission of flammable gases such as SiH4 (silane) and PH3 (phosphine), a double-tube design is required (the inner tube is EP high-purity tubing, the outer tube is filled with nitrogen and equipped with a pressure gauge for detection) , in order to achieve the effect of double protection. In addition, the material of special gas cabinets and special gas pipelines and valves must be high-purity stainless steel 6LV or 6LVV, and ultra-high-purity pipe valves with EP (electropolished) treatment on the inner surface to prevent the leakage of corrosive gas.
In the new project of chip factory, there are a lot of site installation and testing work. Most of works are welding, VCR connection, card sleeve joint installation and helium leak measurement. These works need formal installation guidance and training, and only the engineers with the corresponding certificate are qualified to work. Standard and professional construction and installation is the guarantee of the future stable operation of the chip factory.