# US 11,440,009 B2 · Plurality of filters

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- Number: US 11,440,009 B2
- Document ID: US11440009B2
- Status: Granted
- Kind: B2
- Application number: 16/097,460
- Filed: 2016-07-15
- Published: 2019-05-16
- Granted: 2022-09-13
- Earliest claimed: 2016-07-15
- Assignees: Hewlett-Packard Development Company, L.P.
- Applicants: Hewlett-Packard Development Company, L.P.
- Inventors: Chien-Hua Chen; Michael W. Cumbie; Devin Alexander Mourey
- Web page: https://patentgrep.com/patent/US11440009B2

## CPC

- B01L 3/502753: {characterised by bulk separation arrangements on lab-on-a-chip devices, e.g. for filtration or centrifugation}
- B01D 29/01: with flat filtering elements (B01D29/39 takes precedence)
- B01D 29/012: {Making filtering elements (making bag, cage, hose, tube, sleeve or like filtering elements B01D29/111)}
- B01D 29/03: self-supporting
- B01D 29/56: in series connection
- B01L 3/502707: {characterised by the manufacture of the container or its components}
- B81B 1/006: {Microdevices formed as a single homogeneous piece, i.e. wherein the mechanical function is obtained by the use of the device, e.g. cutters}
- B81C 1/00119: {Arrangement of basic structures like cavities or channels, e.g. suitable for microfluidic systems}
- B01L 2200/0631: Purification arrangements, e.g. solid phase extraction [SPE]
- B01L 2300/0645: Electrodes
- B01L 2300/0681: Filter
- B01L 2300/0883: Serpentine channels
- B01L 2300/0887: Laminated structure
- B01L 2400/0415: electrical forces, e.g. electrokinetic
- B81B 2201/10: Microfilters, e.g. for gas or fluids
- B81B 2203/0338: Channels
- B81B 2203/0353: Holes
- B81C 2201/0125: Blanket removal, e.g. polishing
- B81C 2201/013: Etching
- B81C 2203/03: Bonding two components
- B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00)
- B81C: PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS (making microcapsules or microballoons B01J13/02; processes or apparatus specially adapted for the manufacture or treatment of piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/01)

## Abstract

A method may include etching a number of holes into a carrier wafer layer to form a plurality of filters in the carrier wafer layer, patterning a chamber layer over a first side of the carrier wafer layer to form chambers above each filter formed in the carrier wafer layer, forming a layer over the chamber layer, grinding a second side of the carrier wafer layer to expose the number of holes etched into the carrier wafer layer, and bonding a molded substrate to the carrier wafer layer opposite the chamber layer.

## Claims

### Claim 1

A fluidic microelectromechanical system (MEMS) device, comprising:
a substrate;
a die bonded to the substrate; and
a top layer bonded to the die opposite the substrate, wherein the top layer and the substrate each comprise a wall to form a chamber to retain an analyte between the top layer and substrate within the MEMS device;
a number of measurement electrodes disposed within the chamber;
a number of stand-off features disposed within the chamber, wherein the number of stand-off features:
are not a full height of the chamber; and
form a lattice structure wherein smaller components of an analyte pass between sections of the lattice structure; and
a crossflow microfluidic channel comprising a flowing inert fluid, wherein the crossflow microfluidic channel is perpendicular to the chamber to draw, via crossflows, the analyte away from the chamber;
wherein the die comprises a plurality of filters with each filter comprising a number of holes defined through the die perpendicular to a plane formed by the substrate; and
wherein an interface between the substrate, die, and top layer creates a serpentine fluidic flow through the plurality of filters.

### Claim 2 (depends on 1)

The fluidic MEMS device of claim 1, further comprising a second filter defined in an intermediate top layer above the die, the second filter being stacked above a filter in the die.

### Claim 3 (depends on 1)

The fluidic MEMS device of claim 1, wherein the stand-off features are disposed above a filter in the die.

### Claim 4 (depends on 3)

The fluidic MEMS device of claim 3, wherein a spacing between the number of standoff stand-off features is greater than a spacing between the number of holes of the filter.

### Claim 5 (depends on 1)

The fluidic MEMS device of claim 1, wherein the plurality of filters comprises a first filter and a second filter.

### Claim 6 (depends on 5)

The fluidic MEMS device of claim 5, wherein the second filter is downstream of the first filter.

### Claim 7 (depends on 6)

The fluidic MEMS device of claim 6, wherein the first filter filters out from the analyte introduced into the MEMS device a first sized component of the analyte and wherein the second filter filters out from the analyte a second sized component of the analyte.

### Claim 8 (depends on 4)

The fluidic MEMS device of claim 4, wherein the crossflow microfluidic channel perpendicular to the chamber is between the first and second filters to cause the second sized component of the analyte to be drawn away from the plurality of filters through the fluidic MEMS device to another portion of the fluidic MEMs device for further processing.

### Claim 9 (depends on 6)

The fluidic MEMS device of claim 6, further comprising a number of horizontal filters defined in a chamber between the first and second filters to prevent a first sized component of the analyte from contacting the second filter.

### Claim 10 (depends on 9)

The fluidic MEMS device of claim 9, wherein the analyte is passed through a bottom surface of the first filter, a top surface of the second filter, and a bottom surface of the third filter.

### Claim 11

A method, comprising:
etching a number of holes into a carrier wafer layer to form a plurality of filters in the carrier wafer layer;
patterning a chamber layer over a first side of the carrier wafer layer to form chambers above each filter formed in the carrier wafer layer;
forming a top layer over the chamber layer;
forming a number of stand-off features within the chamber, wherein the number of stand-off features:
are not a full height of the chamber; and
form a lattice structure wherein smaller components of an analyte pass between sections of the lattice structure;
forming an intermediate top layer filter within a chamber and defined in the top layer;
grinding a second side of the carrier wafer layer to expose the number of holes etched into the carrier wafer layer;
bonding a molded substrate to the carrier wafer layer opposite the chamber layer; and
forming a crossflow microfluidic channel comprising a flowing inert fluid, wherein the crossflow microfluidic channel is perpendicular to the chamber to draw, via crossflows, the analyte away from the chamber.

### Claim 12 (depends on 11)

The method of claim 11, further comprising filling etched holes with a protective material.

### Claim 13 (depends on 11)

The method of claim 11, further comprising etching a first and a second filters into the carrier wafer layer.

### Claim 14 (depends on 11)

The method of claim 11, wherein grinding the carrier wafer layer comprises grinding the carrier wafer layer to a thickness of 50 μm to 150 μm.

### Claim 15 (depends on 11)

The method of claim 11, wherein etching the carrier wafer layer further comprises forming an electrode between two of the filters, and wherein the electrode is a pump electrode to pump the analyte through the filters.

### Claim 16 (depends on 11)

The method of claim 11, wherein the crossflow microfluidic channel is formed between two of the formed filters in the carrier wafer layer.

### Claim 17

A device, comprising:
a plurality of filters formed vertically through a silicon layer of the device, wherein the plurality of filters have different vertical heights;
a number of cross-flowing microfluidic channels placed between at least two of the filters, wherein:
filters in a first cross-flowing microfluidic channel have a first spacing and filters in a second cross-flowing microfluidic channel have a second spacing;
a top layer bonded to the silicon layer and a substrate bonded to the silicon layer each comprise walls to form a chamber retain an analyte between the top layer and substrate within the device;
a number of stand-off features disposed within the chamber, wherein the number of stand-off features:
are not a full height of the chamber; and
form a lattice structure wherein smaller components of the analyte pass between sections of the lattice structure;
an inert fluid within a perpendicular crossflow microfluidic channel to draw, via crossflows, the analyte away from the chamber;
a number of horizontal filters formed on the silicon layer to direct, via crossflows, the analyte to another filter;
a number of electrodes, acting as pumps, formed on the silicon layer of the device within the microfluidic channels;
wherein the plurality of filters each comprise a number of holes defined through their respective layer.

### Claim 18 (depends on 17)

The device of claim 17, wherein:
the number of horizontal filters are upstream of the number of electrodes; and
the number of stand-off features are formed on the silicon layer of the device within the microfluidic channels and downstream of the number of electrodes.

### Claim 19 (depends on 17)

The device of claim 17, wherein the number of holes of the plurality of filters comprise a filter hole standoff layer to enable first sized components of the analyte to flow through the filter while preventing second sized components of the analyte from obstructing the flow of the first sized components through the filter.

### Claim 20 (depends on 19)

The device of claim 19, wherein each of the plurality of filters sequentially filter out of the analyte relatively smaller components of the analyte as the analyte passes through the plurality of filters.