Apparatus for accurate and efficient quality and reliability evaluation of micro electromechanical systems
View Patent ↗The present invention provides multiple test structures for performing reliability and qualification tests on MEMS switch devices. A Test structure for contact and gap characteristic measurements is employed having a serpentine layout simulates rows of upper and lower actuation electrodes. A cascaded switch chain test is used to monitor process defects with large sample sizes. A ring oscillator is used to measure switch speed and switch lifetime. A resistor ladder test structure is configured having each resistor in series with a switch to be tested, and having each switch-resistor pair electrically connected in parallel. Serial/parallel test structures are proposed with MEMS switches working in tandem with switches of established technology. A shift register is used to monitor the open and close state of the MEMS switches. Pull-in voltage, drop-out voltage, activation leakage current, and switch lifetime measurements are performed using the shift register.
1. An apparatus for measuring contact and gap characteristics of MEMS switches comprising:
a plurality of said MEMS switches in an array pattern configured in a circuit, having air gaps between combs of upper and lower actuation electrodes;
a first pair of probe pads electrically connecting to said upper actuation electrodes;
a second pair of probe pads electrically connecting to said lower actuation electrodes; and
a third pair of probe pads electrically connecting to said MEMS switches in said circuit;
such that all of said actuation electrodes are electrically configured in parallel, while said MEMS switches are electrically configured in series, allowing said actuation electrodes to close simultaneously to measure a total actuation leakage current.
2. An apparatus for measuring contact and gap characteristics of MEMS switches comprising:
a plurality of said MEMS switches in an array pattern configured in a circuit, having air gaps between combs of upper and lower actuation electrodes;
a first pair of probe pads electrically connecting to said upper actuation electrodes;
a second pair of probe pads electrically connecting to said lower actuation electrodes;
a third pair of probe pads electrically connecting to said MEMS switches in said circuit;
such that all of said actuation electrodes are electrically configured in parallel, while said MEMS switches are electrically configured in series; and
switch contacts of said MEMS switches arranged such that said MEMS switches close in series and said actuation electrodes in parallel so that an actuation leakage current which is a sum total of each individual actuation leakage current of each of said MEMS switches is measurable, or a contact resistance which is a sum total of each individual contact resistance of each of said MEMS switches is measurable.
3. The apparatus of claim 2 wherein said electrodes are placed in layered segments one over the other to form a compact structure for reducing a size of the apparatus for measuring contact and gap characteristics of MEMS switches.