Microfabricated elastomeric valve and pump systems

• US 8,002,933 B2
• Filed: 11/02/2007
• Issued: 08/23/2011
• Est. Priority Date: 06/28/1999
• Status: Expired due to Fees

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Chou, Hou-Pu, Unger, Marc A., Scherer, Axel, Quake, Stephen R., Thorsen, Todd A.
• Primary Examiner(s): OLSEN, ALLAN W
• Application Number:
  US11/934,235
• Publication Number:
  US 20080210322A1
• Time in Patent Office: 1,390 Days
• Field of Search: None
• US Class Current: 156/242
• CPC Class Codes: B01L 2300/0861 Configuration of multiple channels and/or chambers in a single devices
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2300/123 Flexible; Elastomeric
• CPC Class Codes: B01L 2400/046 Chemical or electrochemical formation of bubbles
• CPC Class Codes: B01L 2400/0481 squeezing of channels or chambers
• CPC Class Codes: B01L 2400/0655 pinch valves
• CPC Class Codes: B01L 3/502707 characterised by the manufacture of the container or its components by shaping or joining plastic parts B29C59/00, B29C65/00; by laminating B32B37/00; manufacture of microstructural devices in general B81C
• CPC Class Codes: B01L 3/50273 characterised by the means or forces applied to move the fluids micropumps F04B19/006, of the membrane type F04B43/043
• CPC Class Codes: B01L 3/502738 characterised by integrated valves microvalves F16K99/0001
• CPC Class Codes: B29C 51/00 Shaping by thermoforming , i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor blow moulding of tubular preforms B29C49/00, deforming of tubular or hollow preforms B29C67/0014
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: B81B 2201/036 Micropumps
• CPC Class Codes: B81B 2201/054 Microvalves
• CPC Class Codes: B81B 5/00 Devices comprising elements which are movable in relation to each other, e.g. comprising slidable or rotatable elements
• CPC Class Codes: B81C 1/00119 Arrangement of basic structures like cavities or channels, e.g. suitable for microfluidic systems
• CPC Class Codes: B81C 2201/019 Bonding or gluing multiple substrate layers
• CPC Class Codes: B81C 2201/034 Moulding
• CPC Class Codes: C12Q 1/6874 involving nucleic acid arrays, e.g. sequencing by hybridisation
• CPC Class Codes: C12Q 2535/125 Allele specific primer extension
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: F04B 43/14 : having plate-like flexible members
• CPC Class Codes: 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
• CPC Class Codes: F15C 5/00 : Manufacture of fluid circuit elements; Manufacture of assemblages of such elements integrated circuits
• CPC Class Codes: F16K 1/20 : with axis of rotation arranged externally of valve member
• CPC Class Codes: F16K 11/20 : operated by separate actuating members with one plug turning in another F16K11/12
• CPC Class Codes: F16K 13/00 : Other constructional types of cut-off apparatus means for plugging pipes or hoses F16L55/10; Arrangements for cutting-off
• CPC Class Codes: F16K 2099/0074 : using photolithography, e.g. etching
• CPC Class Codes: F16K 2099/0076 : using electrical discharge machining [EDM], milling or drilling
• CPC Class Codes: F16K 2099/0078 : using moulding or stamping
• CPC Class Codes: F16K 2099/008 : Multi-layer fabrications
• CPC Class Codes: F16K 2099/0094 : Micropumps
• CPC Class Codes: F16K 31/126 : the fluid acting on a diaphragm, bellows, or the like F16K31/145, F16K31/165, F16K31/365, F16K31/385 take precedence
• CPC Class Codes: 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
• CPC Class Codes: F16K 99/0015 : Diaphragm or membrane valves
• CPC Class Codes: F16K 99/0046 : using magnets
• CPC Class Codes: F16K 99/0048 : using piezoelectric means
• CPC Class Codes: F16K 99/0051 : using electrostatic means
• CPC Class Codes: F16K 99/0059 : actuated by a pilot fluid
• CPC Class Codes: Y10T 137/0491 : Valve or valve element assembling, disassembling, or replacing
• CPC Class Codes: Y10T 137/0497 : Fluid actuated or retarded
• CPC Class Codes: Y10T 137/2224 : Structure of body of device
• CPC Class Codes: Y10T 137/87249 : Multiple inlet with multiple outlet
• CPC Class Codes: Y10T 137/87981 : Common actuator
• CPC Class Codes: Y10T 156/10 : Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 428/24479 : including variation in thickness
• CPC Class Codes: Y10T 428/24744 : Longitudinal or transverse tubular cavity or cell

Abstract

A method of fabricating an elastomeric structure, comprising: forming a first elastomeric layer on top of a first micromachined mold, the first micromachined mold having a first raised protrusion which forms a first recess extending along a bottom surface of the first elastomeric layer; forming a second elastomeric layer on top of a second micromachined mold, the second micromachined mold having a second raised protrusion which forms a second recess extending along a bottom surface of the second elastomeric layer; bonding the bottom surface of the second elastomeric layer onto a top surface of the first elastomeric layer such that a control channel forms in the second recess between the first and second elastomeric layers; and positioning the first elastomeric layer on top of a planar substrate such that a flow channel forms in the first recess between the first elastomeric layer and the planar substrate.

Claims

1. A method of microfabricating an elastomeric structure, comprising:

microfabricating a first elastomeric layer, wherein the first elastomeric layer has a first Young'"'"'s modulus between 20 Pa and 1 GPa;

micro fabricating a second elastomeric layer wherein the second elastomeric layer has a second Young'"'"'s modulus between 20 Pa and 1 GPa;

positioning the second elastomeric layer on top of the first elastomeric layer such that at least one recess in the second layer perpendicularly passes over and is completely separated by a membrane from at least one recess in the first layer; and

bonding a bottom surface of the second elastomeric layer onto a top surface of the first elastomeric layer.

2. The method of claim 1 wherein the first and second elastomeric layers are fabricated on micromachined molds having at least one raised protrusion which forms at least one recess in each of the first and second elastomeric layers.

3. The method of claim 1 wherein the first and second Young'"'"'s moduli are between about 50 Pa and 10 MPa.

4. The method of claim 1 wherein the first and second Young'"'"'s moduli are between about 100 Pa and 1 MPa.

5. The method of claim 1 wherein the first and second elastomeric layers are microfabricated by replication molding.

6. The method of claim 1 wherein the first and second elastomeric layers are microfabricated by sacrificial layer methods.

7. The method of claim 1 wherein the first and second elastomeric layers are microfabricated by injection molding.

8. The method of claim 1 wherein the first and second elastomeric layers are formed of different elastomeric materials.

9. The method of claim 1 further comprising:

sequential addition of further elastomeric layers, whereby each layer is added by;

microfabricating a successive elastomeric layer; and

bonding the bottom surface of the successive elastomeric layer onto a top surface of the elastomeric structure.

10. The method of claim 1 wherein the first elastomeric layer has an excess of a first chemical species and the second elastomeric layer has an excess of a second chemical species.

11. The method of claim 7 wherein the elastomeric layers comprise thermoset elastomers which are bonded together by heating above an elastic/plastic transition temperature of at least one of the first and second elastomeric layers.

12. The method of claim 7 wherein the first chemical species forms bonds with the second chemical species when at least one chemical species is activated.

13. The method of claim 7 wherein the first and second elastomeric layers are composed of the same component materials, but differ in the ratio in which the component materials are mixed together.

14. The method of claim 1 wherein the first and second layers are bonded by a layer of adhesive.

15. The method of claim 1 wherein at least one of the elastomeric layers further comprises a conductive portion.

16. A method of microfabricating an elastomeric structure, comprising:

forming a first elastomeric layer, having a first Young'"'"'s Modulus between 20 Pa and 1 GPa, on a substrate;

curing the first elastomeric layer;

patterning a first sacrificial layer over the first elastomeric layer;

forming a second elastomeric layer, having a second Young'"'"'s Modulus between 20 Pa and 1 GPa, over the first elastomeric layer, thereby encapsulating the first patterned sacrificial layer between the first and second elastomeric layers;

curing the second elastomeric layer;

removing the first patterned sacrificial layer selective to the first elastomeric layer and the second elastomeric layer, thereby forming at least one first recess between the first and second layers of elastomer; and

patterning a second sacrificial layer over the substrate prior to forming the first elastomeric layer, such that the second patterned sacrificial layer is removed during removal of the first patterned sacrificial layer to form at least one recess along a bottom of the first elastomeric layer, wherein the at least one recess along the bottom of the first elastomeric layer is completely separated by a membrane from the at least one first recess between the first and second layers of the elastomer.

17. The method of claim 16 wherein the first and second Young'"'"'s moduli are between about 50 Pa and 10 MPa.

18. The method of claim 16 wherein the first and second Young'"'"'s moduli are between about 100 Pa and 1 MPa.

19. The method of claim 16 further comprising:

patterning a second sacrificial layer over the second elastomeric layer;

forming a third elastomeric layer over the second elastomeric layer, thereby encapsulating the second patterned sacrificial layer between the second and third elastomeric layers; and

curing the third elastomeric layer such that the second patterned sacrificial layer is removed during removal of the first patterned sacrifical layer to form a recess between the second and third elastomeric layers.

20. The method of claim 16 further comprising:

patterning an (n−

1)th sacrifical layer over the nth elastomer layer;

forming a (n+1)th elastomeric layer over the (n−

1)th patterned sacrifical layer; and

bonding the bottom surface of the (n−

1)th elastomeric layer onto a top surface of the nth elastomeric layer thereby encapsulating the (n−

1)th patterned sacrificial layer between the nth and (n+1)th elastomeric layers; and

curing the (n+1) elastomeric layer such that the (n−

1)th patterned sacrificial layer is removed during removal of the first patterned sacrifical layer to form a recess between the nth and (n+1)th elastomeric layers.

21. The method of claim 16 wherein the first patterned sacrificial layer comprises photoresist.

22. The method of claim 16 further comprising bonding the first elastomeric layer to the second elastomeric layer.

23. The method of claim 22 wherein the bonding occurs by interpenetration and reaction of the polymer chains of the uncured elastomer with the polymer chains of the cured elastomer.

24. The method of claim 22 wherein the first elastomeric layer has an excess of a first chemical species and the second elastomeric layer has an excess of a second chemical species.

25. The method of claim 22 wherein the first chemical species forms bonds with the second chemical species when at least one chemical species is activated.

26. The method of claim 22 wherein the first and second elastomeric layers are formed of different elastomeric materials.