Method of testing of MEMS devices on a wafer level

• US 9,034,666 B2
• Filed: 11/07/2011
• Issued: 05/19/2015
• Est. Priority Date: 12/29/2003
• Status: Expired due to Fees

• Current Assignee: Nickolai Belov, Vladimir Vaganov
• Original Assignee: Nickolai Belov, Vladimir Vaganov
• Inventors: Vaganov, Vladimir, Belov, Nickolai
• Primary Examiner(s): Nguyen, Khiem D
• Application Number:
  US13/290,764
• Publication Number:
  US 20120194207A1
• Time in Patent Office: 1,289 Days
• Field of Search: 438/14, 438/16, 438/17, 438/18, 324/750.01
• US Class Current: 438/14
• CPC Class Codes: B81C 99/0045 End test of the packaged device
• CPC Class Codes: G01L 5/162 of piezoresistors
• CPC Class Codes: G01L 5/223 to joystick controls
• CPC Class Codes: G06F 3/0338 with detection of limited linear or angular displacement of an operating part of the device from a neutral position, e.g. isotonic or isometric joysticks

Abstract

Some embodiments provide methods, process, systems and apparatus for use in testing multi-axis Micro Electro Mechanical Systems (MEMS) devices. In some embodiments, methods of testing are provided, comprising: selecting, according to a test specification and a test program, at least a first MEMS device on a substrate comprising a plurality of MEMS formed relative to the substrate and applying one or more electrical probes to the first MEMS device; providing power to the first MEMS device through the one or more electrical probes; measuring output signals of the first MEMS device; applying a force to the first MEMS device using a force actuator; measuring a set of output signals of the first MEMS device based on the applied force; and processing test data and generating output test results according to the test specification and test program.

Claims

1. A method of automated volume electromechanical testing of MEMS devices on a wafer level comprising steps of:

providing a wafer with MEMS devices for testing;

providing a test system comprising probes for electrical contacts to at least one testing MEMS device and a force actuator configured to apply force to at least some areas and at least in some directions to the at least one testing MEMS device;

providing a test specification and a test program;

selecting at least the testing MEMS device according to the test program and applying one or more electrical probes to the testing MEMS device;

providing power to at least the testing MEMS device through the one or more electrical probes;

measuring a first set of output signals of the testing MEMS device;

applying force to the testing MEMS device under at least two different test conditions using the force actuator to apply forces, the at least two different test conditions are chosen from the group of;

one or more forces applied in at least two different locations, and one or more forces applied in at least two non-collinear directions;

measuring a second set of output signals of the testing MEMS device while the force under at least two different test conditions is applied;

determining whether MEMS devices have been tested according to the test program, and choosing the next step, based on whether the MEMS devices have been tested according to the test program, from the group of steps comprising of;

returning back to the group of steps starting with selecting at least one next MEMS device for testing; and

moving further to the step of processing test data;

processing the test data and generating output test results according to the test specification and test program;

whereby at least the second set of output signals corresponding to at least the two different test conditions of applied force are linearly independent, which, after processing, results in characterization of multi-axis MEMS device as at least two-axis MEMS device.

2. A method of claim 1 wherein the force actuator used to apply force to the testing MEMS device is chosen from the group of actuators comprising:

mechanical actuator, magnetic actuator, electromagnetic actuator, electrostatic actuator, thermal actuator, piezoelectric actuator and pneumatic actuator.

3. The method of claim 1 wherein the test program and test specification comprises:

a wafer map;

a number of dice to be tested and their position on the wafer map;

conditions and sequence of testing and acceptable ranges of parameters.

4. The method of claim 1 further comprising the steps of:

applying temperature to the testing MEMS device; and

wherein the measuring the output signals comprises measuring the output signals of the testing MEMS device while the temperature is applied.

5. The method of claim 4, wherein the applying the temperature to the testing MEMS device comprises applying the temperature to the testing MEMS device by a method chosen from the group of:

overall heating of at least the substrate, heating a platen of a chuck, local heating by a laser, local heating by an infrared radiation, local heating by ultraviolet radiation, local heating by a contact heater, local cooling by a flow of decompressed gas, local cooling by a flow of liquid gas, and combination thereof.

6. The method of claim 4, wherein the applied temperature is measured by a temperature sensor integrated within each testing MEMS device.

7. The method of claim 1, wherein the force is applied to at least the testing MEMS device after relative motion of at least the testing MEMS device and at least one tangible component of the force actuator toward each other.

8. The method of claim 1, wherein the force is applied to at least one testing MEMS device in a way chosen from the group of:

applying force in at least two different locations of the testing MEMS device;

applying at least two values of force to the same location of the testing MEMS device;

applying the force to the testing MEMS device in at least two different directions, and combination of the above.

9. The method of claim 1, wherein relative motion of the testing MEMS device and the at least one tangible component of the force actuator toward each other happens during applying electrical probes to at least the testing MEMS device.

10. The method of claim 1, wherein the force is applied to the testing MEMS device by applying one of:

contact force, non-contact force, electrostatic force, pneumatic force, magnetic force, pressure, vibration, shock and combination.

11. The method of claim 1, wherein a magnetic force is applied to the testing MEMS device using a method chosen from the group of:

moving a source of magnetic field relative to the testing MEMS device having a component formed out of ferromagnetic material;

moving a source of magnetic field relative to the testing MEMS device having a conductor carrying a current.

12. The method of claim 1, wherein the force is applied to the testing MEMS device under at least three test conditions and at least three sets of output signals corresponding to at least three test conditions of applied force are linearly independent, which, after processing, results in characterization of multi-axis MEMS device as at least three-axis MEMS device.

13. The method of claim 1, wherein the applying the force to the testing MEMS device comprises applying to the testing MEMS device under M test conditions and at least N (N≦

M) sets of output signals corresponding to the M test conditions of applied force are linearly independent, which after processing results in characterization of multi-axis MEMS device as N-axis MEMS device.

14. The method of claim 1, wherein the testing MEMS device has at least one force-perceiving microstructure for mechanical interaction with the force actuator and the at least one force-perceiving microstructure is chosen from the group of microstructures comprising of:

pin, post, ridge, rim, mesa, bump, beam, trench, cavity, hole, opening, dimple and combination of the above.

15. The method of claim 14, wherein a part of the force actuator mates with the at least one force-perceiving microstructure to achieve a purpose chosen from the group of:

self-alignment of the at least one force-perceiving microstructure with the mating part of the force actuator, creating required test conditions for the testing MEMS device, and combination of the above.