WO2001027581A2

WO2001027581A2 - Force sensing devices with multiple filled and/or empty channels and other attributes

Info

Publication number: WO2001027581A2
Application number: PCT/US2000/021978
Authority: WO
Inventors: Aaron Lewis; Galina Fish; Rima Glazer Dekhter; Sophia Kokotov
Original assignee: Nanoptics, Inc.
Priority date: 1999-09-23
Filing date: 2000-09-21
Publication date: 2001-04-19
Also published as: EP1218947A2; WO2001027581A9; EP1218947A4; WO2001027581A3; JP2003511690A

Abstract

A nanoscale force sensing device includes a probe having a tip with multiple isolated channels (1.1 and 1.2) formed with a tapered (1.3) or untapered (1.4) structure such that two or more materials (solid, liquid or gas) of either the same or different chemical composition are isolated from one another by a solid material, or till (1.5). The device may be either straight or cantilevered and may be mounted to permit detection of surface forces while performing other functions at the same time.

Description

FORCE SENSING DEVICES WITH MULTIPLE FILLED AND/OR EMPTY CHANNELS AND OTHER ATTRIBUTES

I Field of the Invention

This invention is a general method for forming force sensing devices with multiple isolated channels in which two or more materials (solid, liquid or gas) can be isolated one from another. These devices have various attributes that result from this technology that can produce such devices that are either straight or cantilevered. The resulting structures, either cantilevered or uncantilevered, can be tapered to a small tip and should allow for the ability to sense surface forces while using one or multiple channels of the structure for another function.

II Background of the Invention

If there was a general method that could allow for the generation of multiple channel force sensing devices with channels, that could be filled with a solid liquid or gas or left empty or both, this would have significant impact in numerous areas of science and technology. They could form probes that could have multiple attributes such as chemical sensors in one channel with gas in another channel, micro vacuum devices with single channels that could suck up materials and air in a second channel to release such materials, unique nanometric thermocouples, micro voltage, micro capacitance, micro inductive, micromagnetic devices depending on electrical isolation or contact at the tip of electrically conducting materials, microlight detectors if the conductors in the channels are covered with photodetecting materials, microlight sources if the channels of conducting material are coated with electroluminescent materials, multiple channel fountain pens, multiple channel tips for multiple electrochemical and/or optical measurements, micro heating elements, stable micro devices for annealing, soldering, cutting, etc., Peltier microcooling devices, microdynamic cavitation bubble forming devices, generating devices with two isolated electrodes with appropriate electrical inputs, etc. In the past, some of these applications were attempted with single channel devices with less than successful results. For example, microthermocouples with force sensing capabilities have been previously described using a tip that is produced with silicon technology that is then combined with coating procedures to effect a point thermocouple or thermoresistor at the tip of a cantilevered structure. Nonetheless, these coating techniques are very susceptible to the destruction of the point contact at the tip when such tips are employed in contact with a sample surface. The newly invented techniques described in this patent avoid such problems and also allow the production of new structures that were not permitted by such previous technology [C. Prater and T. B. Albrecht, Universal Microfabricated Probe for Scanning Probe Microscopes. U.S. Patent 5.166.520] that was based on some sort of combination of etching or coating rather than the forming procedures used and possible in this invention.

III State of Prior Art

There has been no approach that has been used in the past that would allow the production of the structures described in this patent. Thus, both in terms of the methodology that is described and the type of structures and the devices that can be obtained this is a significant invention over the state of prior art.

IV Summary of the Invention

The invention is a method to produce a type of probe based on multiple channels of isolated materials that can, if so desired, be cantilevered. The structures and the variety of applications that they provide are a result of the ability of these devices to sense surface forces and thus permit the control of these probes at or above specified surfaces in order to accomplish specific applications.

V Figures

The foregoing, and additional objects, features and advantages of the invention will become apparent to those of skill in the art from the following detailed description of preferred embodiments thereof, taken with the accompanying drawings, in which:

Figure 1 illustrates an example of a multiple channel tapered structure that is part of this invention;

Figure 2 illustrates a structure similar to Figure 1 which is cantilevered;

Figure 3 illustrates another example of a multichannel structure as described herein: and

Figure 4 illustrates an example of a structure produced by the glass forming technology approach described herein. VI Description of the Invention

The invention is a general method and the resulting devices in which multiple channels (1.1 and 1.2) in Figure 1 can be formed into a tapered (illustrated at 1.3) or untapered structure (1.4) such that two or more materials (solid, liquid or gas) of either the same or different chemical composition are isolated from one another by a solid material, or till, (1.5) in the tip of the structure. At this tip the two materials can either be connected or left unconnected, depending on the application that is desired. Such structures can have force constants both as straight or cantilevered devices (see Figure 2 with channels 2.1 and 2.2 in a cantilevered, tapered structure 2.3) that allow for force sensing applications. In addition to the two channel devices shown in Figure 1. multiple channels can also be produced that mix many of the attributes that are described above. An example of such a tapered structure (3.0) is shown in Figure 3, where three multiple channels are illustrated at 3.1, 3.2 and 3.3 in a straight (non-cantilevered) emulation. Nonetheless, this does not limit these structures to three channels and such structures can be made with more than three channels. Furthermore, the three channel structures and structures with additional channels can be cantilevered as shown in Figure 2.

As only one example of such a force sensing multiple device structure, we have produced, using theta glass capillaries, a two-wire cantilevered structure that can be used for thermal resistance when the two isolated materials are metal and of the same composition, and can be used as a thermocouple or a Peltier cooler when the two materials are of different metallic composition. This was accomplished using glass forming technology in the which a multiple channel glass capillary such as that illustrated in Figure 2, with a metal wire (2.4 and 2.5) in each channel (2.1 and 2.2, respectively) is pulled under heating, tension and cooling that is microprocessor controlled. The two channels together with two metal wires in the channels produce a structure that has two tapered wires isolated by glass that can be either left straight or can be cantilevered.

In order to produce such a structure, it is important to choose the condition of tapering such that when the tapering is accomplished by heating, combinations of symmetry and asymmetry of the structures are chosen in order to provide the best results for the specific device that is going to be produced. An example of such a tapered multiple wire structure (4.1) is shown in Figure 4. In this structure the size of the tip is 100 nanometers. However, such structures can be made from many tens of millimeters to single nanometers and can also be coated with metallic material (2.6 in Figure 2) on the outside surface of the multiple channels. Furthermore, for specific applications, such as a micro vacuum devices which have not been produced previously, it is possible to use the same technology to produce a single channel vacuum device using a capillary in which there is only one channel. Finally, all such devices can be produced with a mirror deposited on the tip in order to allow for specific techniques of force sensing.

The above does not limit the method of producing such structures since procedures based on micro electro mechanical (MEMs) techniques could also be applied to produce such tapered structures with force sensing capabilities. When these techniques are applied, it is important to choose the conditions depending on the structure in order that the distance between the two channels after tapering is appropriate to the device that is being produced.

VII Advantages over Prior Art

The availability of such multiple isolated force sensing channels provides a whole new arena of devices that can be applied in many areas of science and technology. In many instances it provides for new capabilities that are not available today, and in other areas it greatly improves the flexibility and reliability of some applications that can be accomplished with significant difficulty.

VIII Applications

With this invention, numerous applications are now possible or can be significantly improved. For example, these structures could act as probes that could have multiple attributes such as chemical sensors in one channel with gas in another channel, can be micro vacuum devices with a single channel that could suck up materials and air and a second channel to release such materials, can be unique nanometric thermocouples, thermoresistors, micro voltage, micro capacitance, micro inductive, and micromagnetic devices, depending on electrical isolation or contact at the tip of electrically conducting materials, can be microlight detectors if the conductors in the channels are covered with photodetecting materials, microlight sources if the channels of conducting material are coated with electroluminescent materials, multiple channel fountain pens, multiple channel tips for multiple electrochemical and/or optical measurements, micro heating elements, can be stable micro devices for annealing, soldering, cutting, etc., or can be Peltier microcooling devices, microdynamic cavitation bubble forming devices, micro plasma generating devices with two isolated electrodes with appropriate electrical inputs, etc. In the past, some of these applications were attempted with single channel devices with less than successful results. Such a list is, of course, not exhaustive and various applications will now be possible with the availability of such devices.

Claims

What is claimed is:

1. A method to produce a multichannel device in which different materials (solid, liquid or gas) of either the same or different chemical composition are isolated from one another by a solid material till, the force sensing tip of a tapered structure that can have a size from 1.000 microns to single nanometers and the materials can either be connected or left unconnected at the tip depending on the application that is desired.

2. A method as in claim 1 in which two metallic materials are chosen for thermal resistance or thermocouple or microinductive or micromagnetic applications.

3. A method as in claim 1 in which two metallic materials are chosen for micro heating or micro cooling Peltier applications.

4. A method as in claim 1 in which metallic wires are chosen for microvoltage or micro current or micro resistance or micro capacitance application.

5. A method as in claim 1 in which one channel is an electrochemical sensor while the other channel is an optical sensor.

6. A method as in claim 1 in which multiple channels are used for the delivery of multiple chemical species for reaction at the tip of the structure or on a surface.

7. A method as in claim 1 in which one channel is left free for the passage of chemicals while the second passage is a metallic wire or an optical fiber or a sensing material.

8. A method in claim 1 in which one channel has a vacuum in order to vacuum or lift particles while in the other channel there is positive pressure to release particles.

9. A method that uses the same technology as in claim 1 but permits only a single channel tapered cantilevered vacuum device to be produced.

10. A method as in claim 1 in which multiple channels are formed to make a micro soldering, annealing and/or cutting devices.

1 1. A method as in claim 1 in which multiple channels are formed to make a micro electroluminescent device and/or micro photodetector by depositing appropriate materials for light production or detection on multiple channels two of which are conducting.

12. A method as in claim 1 which produces a microcutting or a microdynamic device through the direct production of heat or through the production of cavitation bubbles by micro heating liquid that surrounds, for example, tissue or cavitation bubble induced light or other phenomena that result from cavitation bubbles.

13. A method as in claim 1 which produces a microcutting or a microdynamic device through the direct production of microplasma in surrounding materials including tissues or light or other phenomena that result from plasmas.

14. A method as in claim 12 in which the tip can be as large as millimeters without force sensing attributes.

15. A method as in claim 13 in which the tip can be as large as millimeters without force sending attributes.

16. A method as in claims 1 to 15 in which multiple combinations as described in these claims are inserted into one device.

17. A method as in claims 1 to 15 in which metallic coatings are deposited on the outside of the structure.

18. A method as in claims 1 to 14 in which a mirror is deposited or formed on a multiple or single channel structure that would allow for lateral force sensing schemes to be employed.

19. A multichannel device in which the different materials (solid, liquid or gas) of either the same or different chemical composition are isolated from one another by a solid material till the force sensing tip of a tapered structure that can have a size from tens of microns to single nanometers and the materials can either be connected or left unconnected at the tip depending on the application that is desired.

20. A multichannel device in which different materials (solid, liquid or gas) of either the same or different chemical composition are isolated from one another by a solid material till the force sensing tip of a tapered structure that can have a size from 1 ,000 microns to single nanometers and the materials can either be connected or left unconnected at the tip depending on the application that is desired.

21. A device as in claim 20 in which two metallic materials are chosen for thermal resistance or thermocouple or microinductive or micromagnetic applications.

22. A device as in claim 20 in which two metallic materials are chosen for micro heating or micro cooling Peltier applications.

23. A device as in claim 20 in which metallic wires are chosen for microvoltage or micro current or micro resistance or micro capacitance applications.

24. A device as in claim 20 in which one channel is an electrochemical sensor while the other channel is an optical sensor.

25. A device as in claim 20 in which multiple channels are used for the delivery of multiple chemical species for reaction at the tip of the structure or on a surface.

26. A device as in claim 20 in which one channel is left free for the passage of chemicals while the second passage is a metallic wire or an optical fiber or a sensing material.

27. A device as in claim 20 in which one channel has a vacuum in order to vacuum or lift particles while in the other channel there is positive pressure to release particles.

28. A device that uses the same technology as in claim 20 but permits only a single channel tapered cantilevered vacuum device to be produced.

29. A device as in claim 20 in which multiple channels are formed to make a micro soldering, annealing and/or cutting devices.

30. A device as in claim 20 in which multiple channels are formed to make a micro electroluminescent device and/or micro photodetector by depositing appropriate materials for light production or detection on multiple channels two or which are conducting.

31. A device as in claim 20 which produces a microcutting or a microdynamic device through the direct production of heat or through the production of cavitation bubbles by microheating liquid that surrounds, for example, tissue or cavitation bubble induced light or other phenomena that result from cavitation bubbles.

32. A device as in claim 20 which produces a microcutting or a microdynamic device through the direct production of microplasma in surrounding materials including tissues or light or other phenomena that result from plasmas.

33. A device as in claim 31 in which the tip can be as large as millimeters without force sensing attributes.

34. A device as in claim 32 in which the tip can be as large as millimeters without force sensing attributes.

35. A device as in claims 1 to 34 in which multiple combinations as described in these claims are inserted into one device.

36. A device as in claim 1 to 34 in which metallic coatings are deposited on the outside of the structure.

37. A device as in claims 1 to 36 in which a mirror is deposited or formed on a multiple or single channel structure that would allow for lateral force sensing schemes to be employed.