Minienvironment Process Monitor: MiniNet

Particle sources emit a plume of particles which moves according to the forces of air flow, gravity, and electrostatic attraction. In minienvironments, particle events are often localized and may not be detectable at the center of the enclosure.

Using 5-7 sample points instead of one, ensemble sampling increases coverage, thus increasing the probability of event particle detection. This in turn enables increased yield.

Field Study: 300 mm Fab

Data was collected from a wafer sorting tool in a 300 mm fab. The MiniNet sampled from 7 positions spread throughout the minienvironment, typically 6" below the door or robot arm/track of interest. As a control, a Lasair^® 110 (0.1 µm sensitivity at 1 CFM flow rate) sampled from the center of the enclosure, also 6" below.

As can be seen from the graph at right, the MiniNet (in red) detected numerous particle events that the single-point particle counter (in blue) missed. Further, the MiniNet counted an order of magnitude higher of particles, plus continued to detect them over a longer time period.

For more information, please see the following:

• Why is it important to monitor Minienvironments?
• What is the MiniNet? How does it work?
• What are the benefits of using MiniNet?
• Back to the Main MiniNet page