Wafer Charging Monitors, Inc.

How CHARM®-2 wafers are used...  

The re-usable CHARM®-2 wafers are first calibrated and programmed on a parametric tester, then placed in a process chamber and exposed to a short version of the process to be tested. The collected charge or UV produced by this process alters the threshold voltage of the EEPROM transistors in the CHARM®-2 sensors. The CHARM®-2 wafers are then tested on a parametric tester (any of several standard makes and models) to collect the charging data, after which they can be re-programmed on the same parametric tester to get them ready for the next application. In this way, the CHARM®-2 charging monitor wafers may be used again and again to quantify the charging characteristics of any IC process equipment, including ion implanters, resist ashers, plasma etchers, and plasma deposition systems.