Trace Ammonia Gas Monitor

The First Step in Preventing "Foreign Particles" & "HAZE"
With the increasingly minute processing required in semiconductor manufacturing, ever stricter control of production flow has also become necessary. This is particularly true of current lithography process, where tight control of the process atmosphere is required. With lithography, control of trace ammonia gas has grown in importance, due to its role as a cause of HAZE. Hazing generates foreign particles on the surface of the mask and also clouds the internal lens of the exposure unit. To address the problems this ultra-low concentration gas causes in conventional measuring methods, it has been necessary to develop real-time monitoring of the substance. HORIBA meets this important need with the CG-1000 Trace Ammonia Gas Monitor. The CG-1000 features new CRDS measurement technology and is designed for in-process versatility.

0.1 ppb Sensitivity
Despite its compact design, the CG-1000 features an effective light path length that extends up to several kilometers. This has given the unit an extremely lower detection limit of 0.1 ppb.

Real-time Measurement
Concentration readings are output every five seconds, enabling real-time measurement of ammonia gas.

Easy Operation
Measurement can be started just by connecting the sampling line and turning on the power. This greatly simplifies usage of the unit.

Low Running Costs
Maintenance or replacement of consumables such as carrier gas and columns is not required with the CG-1000, significantly decreasing operating costs.

Extended Stability
As it is the decay time of light being measured, fluctuations in laser intensity or marks on the mirror have minimal effect. Additionally, the unit has no moving parts, ensuring excellent long-term stability.

CRDS (Cavity Ring Down Spectroscopy) The CRDS method traps laser light inside an optical cavity using high-efficiency reflectors and then monitors the decay time of light that escapes from this cavity. This enables the absorbance of any sample in the cavity to be measured. CRDS uses a light path with a length of several kilometers, which allows it to perform measurement with great sensitivity. In addition, as this method measures the decay time of light, it has the advantage of not being affected by fluctuations in the laser intensity. For these reasons, CRDS offers both ease of operation and excellent functionality.