Patent ID: 8234003

Claim:
A monitoring device for monitoring an abnormal load or unload operation of a wafer, the monitoring device comprising: a first sensing unit for providing a first sensing information, which indicates whether the wafer protrudes from a side of a carrier; and a detecting unit for determining whether a duration, for which the wafer protrudes from the side of the carrier, exceeds a predetermined time, for which the wafer is loaded or unloaded, according to the first sensing information, and further triggering an abnormal event if the duration exceeds the predetermined time, wherein the detecting unit comprises: a first controlling unit for outputting a detective voltage according to a voltage level of the first sensing information; a setting unit for storing a first storing voltage, and adjusting a level of the first storing voltage according to the detective voltage; an operating unit for selectively enabling latching and selectively providing a second storing voltage according to a level of the first storing voltage; a driving unit controlled by the second storing voltage to provide a driving signal; and a second controlling unit for selectively providing a warning signal according to a voltage level of the driving signal.