Microscale sensors for direct metrology of additively manufactured features

Patent metadata

Field	Value
Publication number	US-10451539-B2
Application number	US-201815910604-A
Country	US
Kind code	B2
Filing date	Mar 2, 2018
Priority date	Mar 2, 2018
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

This invention relates to a microelectromechanical device for mechanical characterization of a specimen. In one embodiment the device may incorporate a substrate, at least one first flexure bearing and at least one second flexure bearing, both being supported on the substrate. First and second movable shuttles may be used which are supported above the substrate by the flexure bearings so that each is free to move linearly relative to the substrate. Ends of the movable shuttles are separated by a gap. A thermal actuator may be connected to one end of the first movable shuttle, and operates to cause the first movable shuttle to move in a direction parallel to the surface of the substrate in response to a signal applied to the thermal actuator. A first capacitive sensor may be formed between the first movable shuttle and the substrate, and a second capacitive sensor formed between the second movable shuttle and the substrate.

First claim

What is claimed is:

1. A microelectromechanical device for mechanical characterization of a specimen, the device comprising:
a substrate;
at least one first flexure bearing supported on the substrate;
a first movable shuttle having first and second ends, and being supported above the substrate by the at least one first flexure bearing so as to be free to move linearly relative to the substrate;
a second movable shuttle having first and second ends, and being supported on the substrate through at least one second flexure bearing so as to be free to move linearly relative to the substrate, wherein the first ends of the first and second movable shuttles are positioned adjacent one another but are separated by a gap, and wherein the first and second movable shuttles are formed from an electrically conductive material;
a thermal actuator connected to the first end of the first movable shuttle, wherein the entirety of the first movable shuttle is a conductive, single layer, monolithic unit, and wherein the specimen is directly formed on or secured to the first ends of the first and second movable shuttles, such that the thermal actuator moves the first movable shuttle in a direction parallel to the surface of the substrate in response to a signal applied to the thermal actuator;
a first capacitive sensor formed between the first movable shuttle and the substrate; and
a second capacitive sensor formed between the second movable shuttle and the substrate.

2. The device of claim 1 , further comprising:
a specimen object secured to the first ends of the first and second movable shuttles and bridging the gap between the first and the second movable shuttle; and
wherein the specimen object comprises at least one of:
an additively manufactured part,
a plurality of biological cells,
a soft material, and
a 2D nanosheet material.

3. The device of claim 1 , further comprising a heat sink connected to the first movable shuttle to thermally isolate the first movable shuttle from the thermal actuator.

4. The device of claim 1 , wherein:
the first and the second movable shuttles each have a bottom surface, and
the bottom surfaces each include a plurality of dimples.

5. The device of claim 1 , wherein the first capacitive sensor includes:
first and second sets of parallel plates;
the first set of parallel plates being movable and attached to the first movable shuttle, and the second set of parallel plates being stationary and attached to the substrate.

6. The device of claim 1 , wherein the second capacitive sensor includes:
first and second sets of parallel plates;
the first set of parallel plates being movable and attached to the second movable shuttle, and the second set of parallel plates being stationary and attached to the substrate.

7. The device of claim 1 , wherein at least one of the first and second flexure bearings comprises a double parallelogram flexure bearing.

8. The device of claim 1 , wherein the at least one first flexure bearing comprises a plurality of linearly spaced apart first flexure bearings, and each one of the linearly spaced apart first flexure bearings each comprise a double parallelogram flexure bearing.

9. The device of claim 1 , further comprising:
a central stage; and
wherein the thermal actuator comprises a set of chevron beams that are connected to the central stage on a first end thereof and to the substrate on a second end thereof, and wherein the central stage is connected to the first movable shuttle of the device.

10. The device of claim 9 , wherein the first movable shuttle, the connection between the first movable shuttle and the thermal actuator, and the central stage of the thermal actuator are made of the same material.

11. The device of claim 1 , wherein a longitudinal axis of the first movable shuttle is collinear with a longitudinal axis of the second movable shuttle.

12. The device of claim 1 , wherein the connection between the first movable shuttle and the thermal actuator comprises a rigid connection.

13. The device of claim 1 , wherein the gap between the first and second movable shuttles is between 1 to 250 micrometers.

14. The device of claim 1 , wherein:
the at least one first flexure comprises at least three distinct first flexure bearings spaced apart along the first movable shuttle for supporting the first movable shuttle at its first and second ends thereof and also at least at one midpoint along a length of the first movable shuttle; and
the at least one second flexure comprises at least three flexure bearings for supporting the second movable shuttle at the first and second ends thereof and also at least at one midpoint along a length of the second movable shuttle.

15. The device of claim 1 , further comprising electrical contact pads to connect the thermal actuator and the two capacitive sensors to at least one external electronics circuit.

16. A method for mechanical characterization of a specimen material using a microelectromechanical system (MEMS) device, the method comprising:
applying specimen material across a gap formed between adjacently positioned ends of a conductive first movable shuttle and a conductive second movable shuttle, such that the specimen material is rigidly affixed to the ends of the first and second movable shuttles, and wherein an entirety of the first movable shuttle is a conductive, single layer, monolithic unit, and wherein the specimen is directly formed on or secured to the adjacently positioned ends of the first and second movable shuttles;
axially moving the first movable shuttle to stretch or compress the specimen material in controlled fashion; and
measuring a displacement of each one of the first and second movable shuttles.

17. The method of claim 16 , further comprising:
evaluating the instantaneous displacement of the specimen material as the difference between the displacements of the two movable shuttles; and
evaluating the instantaneous force experienced by the specimen material from the product of the axial stiffness of the second movable shuttle and the displacement of the second movable shuttle.

18. The method of claim 16 , further comprising the step of maintaining the first movable shuttle at a zero bias voltage during displacement recording.

19. The method of claim 18 , wherein applying the specimen material further comprises an operation of development of the specimen material in one or more liquid mediums to wash away undesired sections of the specimen material.

20. The method of claim 19 , wherein displacements of the first and second movable shuttles are measured by capacitive sensors.

21. Method of claim 19 , wherein displacements are measured by digital image correlation.

22. A method for forming a device able to perform mechanical characterization of submicron features of a specimen material, the method comprising:
supporting a first conductive, movable shuttle above a substrate using a thermal actuator and at least one first flexure bearing;
supporting a second conductive, movable shuttle above the substrate using at least one second flexure bearing;
arranging opposing ends of the first and second movable shuttles adjacent one another to enable the specimen material to be applied to, and to bridge the opposing ends;
arranging a thermal actuator in contact with the first movable shuttle to cause linear movement of the first movable shuttle when a signal is applied to the thermal actuator, and thus to apply at least one of a tensile stre

Assignees

• Saha Sourabh
• Panas Robert Matthew
• Cullinan Michael A
• Ladner Ian Seth
• L Livermore Nat Security Llc
• Univ Texas

Inventors

• Saha Sourabh
• Panas Robert Matthew
• Cullinan Michael A
• Ladner Ian Seth

Classifications

• G01L1/144

  with associated circuitry (G01L1/146 and G01L1/148 take precedence) · CPC title

• G01N2203/0286

  Miniature specimen; Testing on microregions of a specimen · CPC title

• G01N3/08

  by applying steady tensile or compressive forces (G01N3/28 takes precedence) · CPC title

• G01L1/00

  Measuring force or stress, in general (measuring force due to impact G01L5/00) · CPC title

• B81C1/00

  Manufacture or treatment of devices or systems in or on a substrate (B81C3/00 takes precedence) · CPC title