Micro-electromechanical actuator and methods of use and fabrication

• US 20030209768A1
• Filed: 06/12/2003
• Published: 11/13/2003
• Est. Priority Date: 04/23/2002
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Milligan, Donald J.
• Granted Patent: US 6,897,083 B2
• Time in Patent Office: Days
• US Class Current: 257/414
• CPC Class Codes: B81B 2201/038 Microengines and actuators not provided for in B81B2201/031 - B81B2201/037
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: B81C 99/0045 End test of the packaged device

Abstract

A micro-electromechanical actuator and related methods of use that use a pair of electrodes separated by a linkage. The linkage is biased to a neutral position wherein the electrodes are spaced apart from each other, but also allows at least one electrode to move toward the other electrode when an appropriate force, such as voltage from the power source, is applied to the electrodes. The linkage is sized and shaped to allow the electrodes to move together when a defined threshold voltage is applied by the power source, thereby allowing the micro-elecromechanical actuator to function as a manufacturing quality testing device or a micromechanical actuator in other applications. The actuator may be fabricated simultaneously with other micromechanical and micro-electromechanical components on the same substrate using conventional semi-conductor and micro-machining manufacturing equipment.

Claims

1. A micro-electromechanical actuator manufactured into a substrate, said actuator comprising:

a first electrode;

a second electrode operably secured to said substrate; and

,

a linkage operably secured to said first electrode and said substrate and having a neutral position;

wherein said first electrode and said second electrode are spaced apart from each other in said neutral position and said linkage moves to allow said first electrode to contact said second electrode when a voltage at or above a defined level is applied to the first and second electrodes.

2. The micro-electromechanical actuator manufactured into a substrate of claim 1, wherein said first and second electrodes remain spaced apart from each other when a voltage less than said defined level is applied to the electrodes.

3. The micro-electromechanical actuator manufactured into a substrate of claim 1, wherein said linkage has a substantially serpentine pattern.

4. The micro-electromechanical actuator manufactured into a substrate of claim 3, wherein said serpentine pattern includes a plurality of spaced apart beams aligned substantially parallel with each other and operably secured together with spacer portions.

5. The micro-electromechanical actuator manufactured into a substrate of claim 4, wherein said plurality of spaced apart beams includes five beams, and said first electrode is a beam aligned substantially parallel to said five beams in said neutral position.

6. The micro-electromechanical actuator manufactured into a substrate of claim 5, wherein said first electrode and said second electrode are spaced apart from each other by a defined distance in said neutral position.

7. The micro-electromechanical actuator manufactured into a substrate of claim 6, wherein said defined distance is about 25 μ

m.

8. The micro-electromechanical actuator manufactured into a substrate of claim 1, wherein said defined level of voltage is proportional to the flexibility of the substrate, and said actuator is used to test the flexibility of the substrate.

9. The micro-electromechanical actuator manufactured into a substrate of claim 8, wherein said micro-electromechanical actuator is manufactured using the same manufacturing equipment as used to manufacture other micro-mechanical devices on the substrate;

and,

whereby said actuator also tests whether correct manufacturing processes were performed on said substrate.

10. The micro-electromechanical actuator manufactured into a substrate of claim 9, wherein said micro-electromechanical actuator is manufactured concurrently with said other micro-mechanical devices on the substrate.

11. The micro-electromechanical actuator manufactured into a substrate of claim 1, wherein said substrate is a single crystal silicon wafer.

12. The micro-electromechanical actuator manufactured into a substrate of claim 11, wherein said micro-electromechanical actuator is formed on a scribe line on said silicon wafer.

13. The micro-electromechanical actuator manufactured into a substrate of claim 1, further including means for connecting a voltage generator to said first and second electrodes.

14. The micro-electromechanical actuator manufactured into a substrate of claim 13, further including a resistor electrically secured in series to said first electrode.

15. The micro-electromechanical actuator manufactured into a substrate of claim 1, further including a handle wafer operably secured to said substrate, and said micro-electromechanical actuator is operably secured to said handle wafer.

16. The micro-electromechanical actuator manufactured into a substrate of claim 15, wherein a conductive bonding layer operably secures said micro-electromechanical actuator to said handle wafer.

17. A testing device for determining if micro-mechanical and micro-electromechanical devices formed using a flexible substrate have been manufactured within acceptable manufacturing tolerances, said device including:

a linkage operably secured to said substrate and having a neutral position;

a first electrode secured to said linkage; and

,

a second electrode operably secured to said substrate;

wherein said first electrode and said second electrode are spaced apart from each other in said neutral position and said linkage moves to allow said first electrode to contact said second electrode when a voltage at a defined level is applied to the first and second electrodes, said defined level of voltage being proportional to the shape of the linkage for a given flexibility of the substrate such that if said shape of the linkage or said flexibility of said substrate is out of acceptable tolerance, said first electrode will not contact said second electrode when said defined level of voltage is applied to said first and second electrodes.

18. The testing device for determining if micro-mechanical and micro-electromechanical devices formed using a flexible substrate have been manufactured within acceptable manufacturing tolerances of claim 17, wherein said testing device is manufactured using the same manufacturing techniques as those used to manufacture other micro-mechanical devices on the substrate.

19. The testing device for determining if micro-mechanical and micro-electromechanical devices formed using a flexible substrate have been manufactured within acceptable manufacturing tolerances of claim 18, wherein said micro-electromechanical actuator is manufactured concurrently with said other micromechanical devices on the substrate.

20. The testing device for determining if micro-mechanical and micro-electromechanical devices formed using a flexible substrate have been manufactured within acceptable manufacturing tolerances of claim 18, wherein said testing device is formed using conventional semi-conductor manufacturing equipment.

21. The testing device for determining if micro-mechanical and micro-electromechanical devices formed using a flexible substrate have been manufactured within acceptable manufacturing tolerances of claim 17, further including a handle wafer aligned substantially parallel to said substrate and operably secured to said substrate with a bonding layer extending between said handle wafer and said substrate.

22. The testing device for determining if micro-mechanical and micro-electromechanical devices formed using a flexible substrate have been manufactured within acceptable manufacturing tolerances of claim 21, wherein said first electrode is secured to said handle wafer by a first portion of said bonding layer, and said linkage is secured to said handle wafer by a second portion of said bonding layer.

23. The testing device for determining if micro-mechanical and micro-electromechanical devices formed using a flexible substrate have been manufactured within acceptable manufacturing tolerances of claim 22, wherein said first and second portions of bonding layer are conductive.

24. A method for testing the flexibility of a substrate and manufacturing tolerances used to build micro-mechanical and micro-electromechanical devices on that substrate, said method comprising the steps of:

micro-machining a testing device on the substrate, said testing device having a pair of electrodes that short an electrical circuit when a threshold voltage is applied to them, said threshold voltage being proportional to the flexibility of the substrate and the overall shape and dimensions of the testing device such that said pair of electrodes will not short out the electrical circuit at said threshold voltage if said shape or dimensions of the linkage or said flexibility of said substrate are out of acceptable tolerance.

applying the threshold voltage to the pair of electrodes on the testing device to determine if the electrical circuit shorts, thereby determining if one of the flexibility and the manufacturing techniques used on the substrate are out of acceptable tolerance.

25. The method for testing the flexibility of a substrate and manufacturing tolerances used to build micro-mechanical and micro-electromechanical devices on that substrate of claim 24, further including the step of micro-machining other micro-electromechanical or micromechanical components on the substrate using the same equipment used to micro-machine the testing device on the substrate.

26. The method for testing the flexibility of a substrate and manufacturing tolerances used to build micro-mechanical and micro-electromechanical devices on that substrate of claim 25, wherein said micro-machining a testing device on the substrate step and said micro-machining the other micro-mechanical and micro-electromechanical devices on the substrate step are performed concurrently.

27. The method for testing the flexibility of a substrate and manufacturing tolerances used to build micro-mechanical and micro-electromechanical devices on that substrate of claim 25, wherein said micro-machining a testing device on the substrate step and said micro-machining the other micro-mechanical and micro-electromechanical devices on the substrate step are performed using conventional semi-conductor manufacturing and handling equipment.

28. The method for testing the flexibility of a substrate and manufacturing tolerances used to build micro-mechanical and micro-electromechanical devices on that substrate of claim 27, wherein said conventional semi-conductor manufacturing and handling equipment includes masking portions of the substrate with etch resistant material, and etching the substrate to remove portions of the substrate and thereby form structures within the substrate.

29. The method for testing the flexibility of a substrate and manufacturing tolerances used to build micro-mechanical and micro-electromechanical devices on that substrate of claim 28, further including the steps of:

operably securing the substrate to a handle wafer such that openings between the substrate and handle wafer are provided at defined locations; and

,

wherein said micro-machining a testing device on the substrate step includes aligning the moving portions of the testing device with the openings between the substrate and handle wafer such that the moving portions move freely.

30. A method for fabricating a micro-electromechanical actuator containing a linkage into a substrate, said method including:

providing a substantially planar substrate;

operably securing the substrate to a handle wafer such that at least one opening between the substrate and handle wafer is provided at a defined location;

micro-machining the actuator into the substrate such that the linkage is positioned adjacent to the at least one opening between the handle wafer and substrate.

31. The method for fabricating a micro-electromechanical actuator containing a linkage into a substrate of claim 30, wherein said operably securing the substrate to a handle wafer step includes bonding the substrate to the handle wafer with a bonding layer.

32. The method for fabricating a micro-electromechanical actuator containing a linkage into a substrate of claim 31, wherein said bonding the substrate to the handle wafer with a bonding layer includes applying a first bonding agent to a surface on the substrate and applying a second bonding agent to a surface on the handle wafer and joining the first and second bonding agents together to form a bond.

33. The method for fabricating a micro-electromechanical actuator containing a linkage into a substrate of claim 32, further including the step of heading the first and second bonding agents to form the bond.

34. The method for fabricating a micro-electromechanical actuator containing a linkage into a substrate of claim 31, wherein said linkage and bonding layer are conductive, and further including the steps of:

micro-machining a first electrode into the linkage and micro-machining a second electrode into the substrate; and

,

applying a defined voltage to said first and second electrodes to urge the linkage to move the first electrode toward the second electrode.