Application of Gas Sensors in the Semiconductor Manufacturing Industry

In the semiconductor industry, which mainly uses silicon materials, a wide variety of gases are involved in processes such as vapor deposition, ion implantation, plasma etching, passivation and protection.

The main hazards in the semiconductor industry are toxic gases and corrosive gases.Highly toxic gases include germane (GeH₄), phosphine (PH₃), arsine (AsH₃), stibine (SbH₃), phosphorus trifluoride (PF₃), etc.Gases with low toxicity but irritant properties include ammonia (NH₃), silane (SiH₄), boron trifluoride (BF₃), sulfur tetrafluoride (SF₄), etc.Highly corrosive gases include SiF₄, HF, etc.

Among them, silane, commonly used for vapor deposition of silicon and its compounds, will spontaneously ignite in air at room temperature when its concentration exceeds 1%, easily causing fires.Phosphine and arsine, used in epitaxy, doping and other processes, have strong hemolytic toxicity and are the primary detection gases together with silane in the semiconductor industry.

Chlorine-based gases, often used in the etching of III-V materials, can easily irritate the eyes and upper respiratory tract, with a typical alarm point of about 8 ppm.Some gases such as SF₆ are mainly used for etching silicon and its compounds. Although pure SF₆ is non-toxic, it decomposes into a series of toxic gases including SF₄, S₂F₂, HF under high-temperature electric arcs.Therefore, these sulfur-containing or fluorine-containing toxic gases are also key monitoring targets in the semiconductor industry.

Due to the wide variety of hazardous gases in the semiconductor industry, factories in this sector require a large number of gas alarms.At present, most gas-sensing elements used in this field are electrochemical gas sensors.