# US 7,607,455 B2 · Micro-electro-mechanical valves and pumps and methods of fabricating same

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- Number: US 7,607,455 B2
- Document ID: US7607455B2
- Status: Granted
- Kind: B2
- Application number: 12/127,975
- Filed: 2008-05-28
- Published: 2008-10-09
- Granted: 2009-10-27
- Earliest claimed: 2006-03-14
- Assignees: International Business Machines Corporation
- Inventors: Toshiharu Furukawa; Mark Charles Hakey; Steven John Holmes; David Vaclav Horak; Charles William Koburger, III
- Web page: https://patentgrep.com/patent/US7607455B2

## CPC

- F15C 1/06: Constructional details; Selection of specified materials {; Constructional realisation of one single element; Canal shapes; Jet nozzles; Assembling an element with other devices, only if the element forms the main part (F15C5/00 takes precedence)}
- F04B 43/043: {Micropumps}
- F15C 5/00: Manufacture of fluid circuit elements; Manufacture of assemblages of such elements {integrated circuits}
- F16K 99/0001: {Microvalves (microdevices B81B1/00; manufacture or treatment of devices or systems in or on a substrate B81C1/00; microfluidic structures B01L3/5027; micropumps F04B19/006)}
- F16K 99/0015: {Diaphragm or membrane valves}
- F16K 99/0051: {using electrostatic means}
- F16K 2099/0074: {using photolithography, e.g. etching}
- F16K 2099/0094: {Micropumps}
- Y10T 29/49236: Fluid pump or compressor making
- Y10T 29/49412: with assembly, disassembly or composite article making
- Y10T 137/2224: Structure of body of device
- F15C: FLUID-CIRCUIT ELEMENTS PREDOMINANTLY USED FOR COMPUTING OR CONTROL PURPOSES (transducers F15B5/00, {F15B21/00}; fluid dynamics in general F15D; computer comprising fluid elements G06D, G06G; {electric control by means of electro-hydraulic or electro-pneumatic amplifiers G05B7/02})
- F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F)
- F16K: VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING {(devices for emptying and evacuating the excess liquid in valves or conduits F16L55/07)}
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Micro-valves and micro-pumps and methods of fabricating micro-valves and micro-pumps. The micro-valves and micro-pumps include electrically conductive diaphragms fabricated from electrically conductive nano-fibers. Fluid flow through the micro-valves and pumping action of the micro-pumps is accomplished by applying electrostatic forces to the electrically conductive diaphragms.

## Claims

### Claim 1

A micro-valve having an inlet and an outlet, said micro-valve comprising:
a lower chamber having a bottom wall and sidewalls and an upper chamber having a top wall and sidewalls, a bottom of said upper chamber separated from a top of said lower chamber by a porous, flexible and electrically conductive mat of nano-fibers;
an opening in said top wall of said upper chamber, said opening open to said upper chamber;
an impervious valve seal on said mat of nano-fibers, said valve seal below and self-aligned to said opening;
an electrically conductive plate under and electrically isolated from said bottom wall of said lower chamber;
a first electrical contact to said conductive plate; and
a second electrical contact to said mat of nano-fibers.

### Claim 2 (depends on 1)

The micro-valve of claim 1, wherein said outlet comprises said opening in said top wall of said upper chamber and said inlet comprises an additional opening in said top wall of said upper chamber.

### Claim 3 (depends on 2)

The micro-valve of claim 2, wherein said micro-valve is a normally-open valve.

### Claim 4 (depends on 1)

The micro-valve of claim 1, further including:
a valve seat defined by an edge of said opening along an interior surface of said top wall of said upper chamber.

### Claim 5 (depends on 1)

The micro-valve of claim 1, further including a valve seat formed on sidewalls of said opening.

### Claim 6 (depends on 1)

The micro-valve of claim 1, wherein a region of said top wall of said upper chamber adjacent to said opening is thicker than a region of said top wall of said upper chamber away from said opening.

### Claim 7 (depends on 6)

The micro-valve of claim 6, wherein said outlet comprises said opening in said top wall of said upper chamber and said inlet comprises an additional opening in said top wall of said upper chamber.

### Claim 8 (depends on 7)

The micro-valve of claim 7, wherein said micro-valve is a normally-closed valve.

### Claim 9 (depends on 6)

The micro-valve of claim 6, further including:
a valve seat defined by an edge of said opening along an interior surface of said top wall of said upper chamber.

### Claim 10 (depends on 1)

The micro-valve of claim 1, further including:
an additional conductive plate on top of said upper chamber;
a third electrical contact to said additional conductive plate; and
an additional opening into said bottom chamber, said inlet comprised of said additional opening and said outlet comprised of said opening.

### Claim 11 (depends on 10)

The micro-valve of claim 10, wherein said micro-valve is a normally-open valve.

### Claim 12 (depends on 1)

The micro-valve of claim 1, further including:
a protective coating on nano-fibers of said mat of nano-fibers.

### Claim 13 (depends on 1)

The micro-valve of claim 1, wherein said valve seal is pushed against or pulled away from said opening in response to electrostatic forces applied to said mat of nano-fibers.

### Claim 14 (depends on 1)

The micro-valve of claim 1, wherein said micro-fibers are silicon filaments or carbon nanotubes.

### Claim 15

A micro-pump having an inlet and an outlet, said micro-pump comprising:
a first lower chamber having a bottom wall and sidewalls, a second lower chamber having a bottom wall and sidewalls, a third lower chamber having a bottom wall and sidewalls, and an upper chamber having a top wall and sidewalls, a first region of a bottom of said upper chamber separated from a top of said first lower chamber by a porous, flexible and electrically conductive first mat of nano-fibers, a second region of said bottom of said upper chamber separated from a top of said second lower chamber by a non-porous, flexible and electrically conductive second mat of nano-fibers, and a third region of said bottom of said upper chamber separated from a top of said third lower chamber by a porous, flexible and electrically conductive third mat of nano-fibers, said first, second and third mats of nano-fibers electrically isolated from each other;
openings in said top wall of said upper chamber aligned only over said first and third mats of nano-fibers, a first opening of said openings aligned over said first mat of nano- fibers and a second opening of said openings aligned over said third mat of nano-fibers;
an impervious first valve seal on said first mat of nano-fibers, said first valve seal below and self-aligned to said first opening;
an impervious second valve seal on said third mat of nano-fibers, said second valve seal below and self-aligned to said second opening;
a first electrically conductive plate under said bottom walls of said first, second and third lower chambers and a second electrically conductive plate above said top wall of said lower chamber;
a first electrical contact to said first mat of nano-fibers;
a second electrical contact to said second mat of nano-fibers;
a third electrical contact to said third mat of nano-fibers;
a fourth electrical contact to said first conductive plate; and
a fifth electrical contact to said second conductive plate.

### Claim 16 (depends on 15)

The micro-pump of claim 15, wherein said inlet comprises said first opening in said top wall of said upper chamber and said outlet comprises said second opening in said top wall of said upper chamber.

### Claim 17 (depends on 15)

The micro-pump of claim 15, further including:
a first valve seat defined by an edge of said first opening along an interior surface of said top wall of said upper chamber; and
a second valve seat defined by an edge of said second opening along said interior surface of said top wall of said upper chamber.

### Claim 18 (depends on 15)

The micro-pump of claim 15, further including:
a first valve seat formed on sidewalls of said first opening and a second valve seat formed on sidewalls of said second opening.

### Claim 19 (depends on 15)

The micro-pump of claim 15, wherein regions of said top wall of said upper chamber adjacent to said first and second openings are thicker than regions of said top wall of said upper chamber away from said first and second openings.

### Claim 20 (depends on 19)

The micro-pump of claim 19, further including:
a first valve seat defined by an edge of said first opening along an interior surface of said top wall of said upper chamber; and
a second valve seat defined by an edge of said second opening along said interior surface of said top wall of said upper chamber.

### Claim 21 (depends on 15)

The micro-pump of claim 15, further including:
a coating on said second mat of nano-fibers, said coating filling voids between said nano-fibers of said second mat of carbon nano-tubes.

### Claim 22 (depends on 15)

The micro-pump of claim 15, wherein said first and second seals are pushed against or pulled away from respective said first and second openings in response to electrostatic forces applied to said first and third mats of nano-fibers.

### Claim 23 (depends on 15)

The micro-pump of claim 15, wherein said second mat of nano-fibers is deflectable into and out of said upper chamber and into and out of said second lower chamber in response to electrostatic forces applied to said first and third mats of nano-fibers.

### Claim 24 (depends on 15)

The micro-pump of claim 15, wherein said micro-fibers are silicon filaments.

### Claim 25 (depends on 15)

The micro-pump of claim 15, wherein said micro-fibers are carbon nanotubes.

### Claim 26

A method of fabricating a micro-valve having an inlet and an outlet, said method comprising:
on a substrate, forming a lower chamber having a bottom wall and sidewalls and forming an upper chamber having a top wall and sidewalls, a bottom of said upper chamber separated from a top of said lower chamber by a porous, flexible and electrically conductive mat of nano-fibers;
forming an opening in said top wall of said upper chamber, said opening open to said upper chamber;
forming an impervious valve seal on said mat of nano-fibers, said valve seat below and self-aligned to said opening;
forming an electrically conductive plate under and electrically isolated from said bottom wall of said lower chamber, said first conductive plate formed on an insulating layer formed on said substrate;
forming a first electrical contact to said conductive plate;
forming a second electrical contact to said mat of nano-fibers;
forming an additional conductive plate on top of said upper chamber;
forming a third electrical contact to said additional conductive plate;
forming an additional opening into said bottom chamber, said inlet comprised of said additional opening and said outlet comprised of said opening;
forming said lower chamber includes forming a first trench in a first dielectric layer formed on said first conductive plate, filling said first trench with a first sacrificial material and forming said porous mat of nano-fibers over said first sacrificial material followed by removing said first sacrificial material; and
forming said upper chamber includes forming a second trench in a second dielectric layer formed on said mat of nano-fibers, filling said second trench with a second sacrificial material, forming a third dielectric layer on said second dielectric layer and said second sacrificial material, forming a second conductive layer on said third dielectric, forming a fourth dielectric layer on said second conductive layer and forming an opening though said fourth dielectric layer, said second conductive layer and said third dielectric layer to said second sacrificial material and removing said second sacrificial material.

### Claim 27 (depends on 26)

The method of claim 26, wherein said outlet comprises said opening in said top wall of said upper chamber and said inlet comprises an additional opening in said top wall of said upper chamber.

### Claim 28 (depends on 26)

The method of claim 26, wherein a valve seat is defined by an edge of said opening along an interior surface of said top wall of said upper chamber.

### Claim 29 (depends on 26)

The method of claim 26 further including:
forming a valve seat on sidewalls of said opening.

### Claim 30 (depends on 26)

The method of claim 26 wherein a region of said top wall of said upper chamber adjacent to said opening is thicker than a region of said top wall of said upper chamber away from said opening.

### Claim 31 (depends on 26)

The method of claim 26 further including:
forming a protective coating on nano-fibers of said mat of nano-fibers.

### Claim 32 (depends on 26)

The method of claim 26 said micro-fibers are silicon filaments or carbon nanotubes.

### Claim 33

A method of fabricating a micro-pump having an inlet and an outlet, said method comprising:
forming a first lower chamber having a bottom wall and sidewalls, forming a second lower chamber having a bottom wall and sidewalls, forming a third lower chamber having a bottom wall and sidewalls and forming an chamber having a top wall and sidewalls, forming a porous, flexible and electrically conductive first mat of nano-fibers, said first mat of nano-fibers separating a first region of a bottom of an upper chamber from a top of said first lower chamber, forming a non-porous, flexible and electrically conductive second mat of nano-fibers, said second mat of nano-fibers separating a second region of said bottom of said upper chamber from a top of said second lower chamber and forming a porous, flexible and electrically conductive third mat of nano-fibers, said third mat of nano-fibers separating a third region of said bottom of said upper chamber from a top of said third lower chamber, said first, second and third mats of nano-fibers electrically isolated from each other;
forming openings in said top wall of said upper chamber aligned only over said first and third mats of nano-fibers, a first opening of said openings aligned over said first mat of nano-fibers and a second opening of said openings aligned over said third mat of nano-fibers;
forming an impervious first valve seal on said first mat of nano-fibers, said first valve seal below and self-aligned to said first opening;
forming an impervious second valve seal on said third mat of nano-fibers, said second valve seal below and self-aligned to said second opening;
forming a first electrically conductive plate under said bottom walls of said first, second and third lower chambers and a second electrically conductive plate above said top wall of said lower chamber;
forming a first electrical contact to said first mat of nano-fibers;
forming a second electrical contact to said second mat of nano-fibers;
forming a third electrical contact to said third mat of nano-fibers;
forming a fourth electrical contact to said first conductive plate; and
forming a fifth electrical contact to said second conductive plate.

### Claim 34 (depends on 33)

The method of claim 33, wherein said inlet comprises said first opening in said top wall of said upper chamber and said outlet comprises said second opening in said top wall of said upper chamber.

### Claim 35 (depends on 33)

The method of claim 33, wherein, a first valve seat is defined by an edge of said first opening along an interior surface of said top wall of said upper chamber and a second valve seat is defined by an edge of said second opening along said interior surface of said top wall of said upper chamber.

### Claim 36 (depends on 33)

The method of claim 33, further including:
forming a first valve seat on sidewalls of said first opening and forming a second valve seat on sidewalls of said second opening.

### Claim 37 (depends on 33)

The method of claim 33: further including:
increasing the thickness of regions of said top wall of said upper chamber adjacent to said first and second opening.

### Claim 38 (depends on 33)

The method of claim 33, further including:
forming a coating on said second mat of nano-fibers, said coating filling voids between nano-fibers of said second mat of carbon nano-tubes.

### Claim 39 (depends on 33)

The method of claim 33, wherein said micro-fibers are silicon filaments or carbon nanotubes.