Residual Gas Analysis (RGA)

Residual Gas analysis (RGA) is commonly done for hermetically sealed microelectronic devices, to detect moisture and other damaging volatile or gaseous compounds in the device cavity. The residual gases released upon controlled heating of a pierced hermetic device are analyzed by mass spectrometry. The laboratory network of Infinita Lab, USA, offers this test to clients in the USA and Canada.

Residual Gas Analysis (RGA)

Residual Gas Analysis (RGA) is an important test for high reliability microelectronic devices used in microcircuits for critical applications in military, aerospace, medical, telecommunications and Industrial Automation. RGA is used, for example, to measure the moisture content of the atmosphere inside a metal or ceramic hermetically sealed microelectronic device, in accordance with Method 1018.2 of MIL-STD-883D. Moisture can occur inside hermetic devices due to Hydrogen evolved in the presence of Nickel used in device packaging, reacting with reducible metal oxides to form Water. In addition to moisture, the use of epoxies and other adhesives or polymeric materials in microelectronic devices can cause outgassing of volatile species due to insufficient curing.

RGA testing to detect all volatile species including moisture is done using Mass Spectrometry. In the case of hermetically sealed micro electronics devices, RGA is a destructive test, since the device must be pierced to sample the cavity atmosphere. 

RGA using mass spectrometry is also used in the process industry and in research equipment, for vacuum leak testing in ultra-high vacuum systems. It enables the partial pressure of gaseous components to be directly determined from the measured gas composition.

The standard RGA test for hermetically sealed microelectronic devices involves placing the sample in a vacuum chamber connected by a transfer passage to a suitably calibrated mass spectrometer. The chamber and transfer passage are heated and maintained at specified temperatures. The sample is then pierced using a sharp piercing tool, operated from outside the vacuum chamber. The tool must be capable of piercing metallic as well as ceramic packages. The specimen’s internal gases which are released, are then conveyed to the mass spectrometer for analysis. Most Mass spectrometers used in RGA utilize Quadrupole type mass analyzers, which have a wide dynamic range of measurement.

RGA is usually performed in industrial process vacuum systems by compact Mass spectrometers which can be directly installed on the equipment. Samples from equipment can also be collected and subjected to conventional RGA laboratory analysis using Mass spectrometry.

Common Uses of Residual Gas Analysis (RGA)

• Moisture and gaseous component analysis of hermetically sealed microelectronic devices
• Vacuum leak testing and residual gas analysis in ultra-high vacuum equipment

Advantages of Residual Gas Analysis (RGA)

• Sensitive down to parts per billion
• Ability to analyze outgassing problem
• Can determine partial pressure of gaseous component at low pressures

Limitations of Residual Gas Analysis (RGA)

• The analysis by mass spectrometer requires three spectral data covering background, calibration, and sample spectra
• Small devices may have only traces of moisture, which can be masked by external moisture leakage into the vacuum system

Industrial Applications of Residual Gas Analysis (RGA)

• Microelectronic device quality control
• Process research and development.
• Vacuum process control
• Sealing quality control,
• Studying outgassing properties of materials in microelectronic components