The present invention involves an electrical
verification method that detects
moisture within the cavity of the
semiconductor or micro-machined device. The method affects an increase in the time for sufficient
water vapor to remain within an unsealed device, so that
instability in the
diode can be measurable over a longer period of time. The method begins with the step of forming at least one reservoir on at least one of the device
wafer and the capping
wafer. The at least one reservoir connects to at least one
diffusion channel, which is in communication with at least one reservoir port. The method further includes the steps of forming a PN junction
diode adjacent to the at least one reservoir port; bonding the device
wafer with the capping wafer to form a cavity; and electrically testing the PN junction
diode as an indication of the presence of
moisture within the cavity. The device
assembly of the present invention includes a capping wafer bonded on a device wafer to form a cavity; at least one reservoir including at least one
diffusion channel for receiving a liquid and retaining
moisture. The at least one
diffusion channel communicates with at least one reservoir port, which is open into the cavity. An exposed PN junction diode is provided adjacent to the at least one reservoir port, and a pair of
metal pads is connected to the exposed PN junction diode.