Gas System of Etch Equipment

0040-77771 DPS ESC

0010-37264 Cooldown Chamber Multi Slot Ass'y

The etching step requires the use of a variety of etching gases, which are also known as process media in the reaction process. The gas system of the etching equipment is responsible for the transportation of the process medium from the gas source to the inside of the reaction chamber, which is mainly composed of a gas box (Gasbox), a homogenizing plate (Gaspanel), a flow meter (MFC), and a pipeline.

The function of the gas box is to adjust the pressure of the gaseous process medium from the gas source (special gas cylinder or the gas pipeline of the wafer fab) through a variety of control valves, and then introduce it into the gas path pipeline of the etching equipment. Because most of the gases used in the manufacture of integrated circuits are dangerous, in order to ensure safety, the cabinet of the gas circuit box is usually coated with anti-corrosion, and an external observation window is set up, and the inside is also in a negative pressure state. In addition, the gas box is equipped with a variety of monitoring systems, which immediately cut off the gas delivery and alarms once a gas leak is detected. The Gaspanel is one of the core components of the gas system, and it is also a semiconductor metal part that is difficult to process. The homogenizing disc is usually composed of four layers of metal discs, each of which has many small holes and complex and small air paths. After the etching gas is adjusted by the gas path box, it enters the pipeline, and then passes through the homogenizing tray, and finally is transported to the reaction chamber at a stable and uniform speed. The homogenizing disc needs to have the characteristics of high temperature resistance, low particle pollution and corrosion resistance, and special methods need to be used to weld between the multi-layer metal discs to prevent internal leakage. Because the homogenizing disc is related to the core air intake step of etching, some equipment companies choose to cooperate with precision metal processing enterprises to develop and produce homogenizing discs; In addition, Fujikin valves in Japan are also important uniform disc manufacturers.

Etching equipment uses a mass flow meter (MFC) to monitor and control the rate at which etching gases enter the reaction chamber. Because the air intake rate is related to the stability of the etching reaction, the etching equipment has high requirements for the flow range, control accuracy, and flow stability response time of the mass flow meter. Flowmeters can be divided into analog circuit type, digital circuit type and pressure change compensation type. The pressure change compensation flowmeter can automatically compensate for the fluctuation of the gas source pressure to ensure the stable flow of gas output to the reaction chamber. The main manufacturer of mass flow meters is Horiba in Japan.