INTEGRALLY MANUFACTURED MICRO-ELECTROFLUIDIC CABLES

• US 20050205136A1
• Filed: 02/28/2001
• Published: 09/22/2005
• Est. Priority Date: 02/29/2000
• Status: Active Grant

• Current Assignee: Alex R. Freeman
• Original Assignee: Alex R. Freeman
• Inventors: Freeman, Alex R.
• Granted Patent: US 7,264,617 B2
• Time in Patent Office: Days
• US Class Current: 137/554
• CPC Class Codes: A01K 11/006 Automatic identification systems for animals, e.g. electronic devices, transponders for animals identification systems for access to feeding pens A01K1/0209; ear tags with electronic identification means A01K11/004
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: Y10T 137/8242 Electrical

Abstract

Flexible microconduits integral at a proximal end to a substrate and adapted for connection to a biological environment at the distal end are provided. Also provided are microsystems with at least one flexible microconduit integral at a proximal end to a substrate and with a distal end that is adapted for connection to a biological environment. The microconduits may be fluid conduits, electrical conduits, or electro-fluidic conduits that transmit both fluids and electrical signals. Methods for fabricating the microconduits and other structures integral with the substrate are also provided.

Claims

1. A microsystem comprising:

a monolithic substrate;

a microconduit anchored at a proximal end with the monolithic substrate, having unanchored remaining length, wherein the microconduit is a coil that can stretch and contract and the free distal end is adapted for implantation in a biological environment;

the microconduit integrally manufactured on the monolithic substrate;

the microconduit comprises a fluid microconduit;

the microconduit is part of the electrical circuit on the monolithic substrate; and

the monolithic substrate having fluidic elements etched in them and connected to the microconduit.

3. The microconduit of claim 1, wherein the microconduit comprises an electrical microconduit.

4. The microconduit of claim 1, wherein the microconduit comprises an electro-fluidic microconduit.

5. The microconduit of claim 1, further comprising a substrate package, wherein the distal end of the microconduit is adapted for connection to the substrate package.

6. The microconduit of claim 1, wherein the distal end is adapted for connection to a second substrate.

7. The microconduit of claim 1, wherein the distal end is adapted for connection to a second microconduit connected to a second substrate.

8. The microconduit of claim 1, wherein the shape of the microconduit is selected from the group consisting of:

smooth curve, curved coil, stove-top and stove-top coil.

9. The at least one microconduit of claim 1, wherein the freedom of movement of the flexible microconduit is constrained to inhibit entanglement with other flexible microconduits.

10. The microconduit of claim 1, wherein the substrate is selected from one or more of the group consisting of:

silicon, silicon coated with a biocompatible polymer, polysilica, polymer, polyurethane, dielectric material, metal, photoresist, glass, and plastic laminate.

11. The microconduit of claim 1, wherein the substrate comprises a microfluidic chip.

12. The microconduit of claim 11, wherein the microfluidic chip is modular.

13. The microconduit of claim 1, wherein the microfluidic chip comprises a flip chip.

14. The microconduit of claim 1, wherein the substrate comprises a microdevice.

15. The microconduit of claim 14, wherein the inicrodevice comprises one or more of the following elements:

an island,

a microvalve,

a micropump,

a microspring,

a microgripper,

a microclamp,

a micro-o-ring,

a fluid reservoir,

an electrode,

a signal generator,

a signal detector,

a microprocessor

a microelectromechanical device,

a microgear,

a microratchet,

a micromixer,

a liquid flow meter,

a chemical analyzer,

a heater, or

a fluid transport channel.

16. The microconduit of claim 15, wherein the micropump is selected from the group consisting of:

a lamb wave device, an electrokinetic pump, an electro-osmotic pump, and a membrane pump.

17. The microconduit of claim 1, wherein the substrate further comprises peripheral or area array pads.

18. The microconduit of claim 1, wherein the outer diameter of the microconduit is in the range of approximately 1 micron to approximately 10 microns.

19. The microconduit of claim 1, wherein the distal end further comprises at least one sensor for sensing a biological, chemical or electrical signal, wherein the microconduit tranmits the signal to the substrate for detection or analysis.

20. The microconduit of claim 1, wherein the biological environment is selected from the group consisting of:

a human, an animal, a plant, tissues cultivated in macro- or micro-culture, and terrestrial, aquatic or atmospheric biological systems or processes.

23. The microsystem of claim 1, wherein the substrate further comprises one or more peripheral or area array pads.

24. The microsystem of claim 23, wherein the one or more array pads comprise solder bumps disposed thereon for connecting modular electronic chips thereto.

25. The microsystem of claim 1, wherein the microconduit comprises a fluid microconduit.

26. The microsystem of claim 1, wherein the microconduit comprises an electrical microconduit.

27. The microsystem of claim 1, wherein the microconduit comprises an electro-fluidic microconduit.

28. The microsystem of claim 1, wherein the outer diameter of the microconduit is in the range of approximately 1 micron to approximately 10 microns.

29. The microsystem of claim 1, wherein the distal end further comprises at least one sensor for sensing a biological, chemical or electrical signal, wherein the microconduit transmits the signal to the substrate for detection or analysis.

30. The microsystem of claim 1, wherein the biological environment is selected from the group consisting of:

a human, an animal, a plant, tissues cultivated in macro- or micro-culture, and terrestrial, aquatic or atmospheric biological systems or processes.

2. (Cancelled)

21. (canceled)

22. (canceled)

31. A method for microfabricating a flexible and liftable microconduit integral with a substrate, the method comprising:

depositing a first patterned dielectric layer on a first sacrificial layer of the substrate;

layering a second sacrificial layer on the first dielectric layer, wherein the second sacrificial layer is patterned;

depositing a second patterned dielectric layer on the second sacrificial layer;

removing the second sacrificial layer to form a trapped fluid microconduit;

removing the first sacrificial layer to flexibly release the microconduit from the substrate, whereby the microconduit is integral to the substrate at a proximal end and liftable from the substrate at a distal end.

32. The method of claim 31, wherein the trapped fluid microconduit is formed by depositing the second dielectric layer with a gap between the second dielectric layer and the sacrificial layer;

removing the sacrificial layer to provide a trapped microconduit with open end; and

oxidizing the microconduit dielectric material after removal of the sacrificial layer to close the open end of the microconduit, thereby forming a closed microconduit passageway.

33. A method of on-substrate microfabrication of flexible electrical microconduits, the method comprising:

layering a sacrificial layer on the substrate;

layering a structural layer on the sacrificial layer to provide mechanical strength;

applying a first dielectric layer on the structural layer;

depositing a patterned conductive layer on the dielectric layer;

layering a capping dielectric layer on the conductive layer, wherein the capping dielectric layer is patterned to provide open windows; and

removing the sacrificial layer to provide a flexible electrical microconduit, whereby the microconduit is integral to the substrate at a proximal end and freely movable at a distal end.

34. A microsystem comprising:

a monolithic substrate having a front side and a back side;

one or more microconduits that are anchored at a proximal end with the monolithic substrate, having unanchored remaining length, wherein the microconduit is a coil that can stretch and contract and the free distal end is adapted for connection to a biological environment;

the microconduit integrally manufactured on the monolithic substrate;

the microconduit comprises a fluid microconduit;

the microconduit is part of the electrical circuit on the monolithic substrate;

the monolithic substrate having fluidic elements etched in them and connected to the microconduit; and

a modular fluidic chip connectable to the monolithic substrate.

35. The microsystem of claim 34, wherein the modular chip is replaceable.

36. The microsystem of claim 34, wherein the modular chip is connectable to the front side or the back side of the substrate.

37. The microsystem of claim 34, wherein the modular chip is connectable to the substrate via a microclamp.

38. The microsystem of claim 37, wherein the microclamp comprises a “

3”

spring.

39. The microsystem of claim 37, wherein the microclamp comprises an “

anchor”

spring.

40. The microsystem of claim 37, wherein the microclamp further comprises an actuator

41. The microsystem of claim 37, wherein the microclamp is thermally actuated.

42. The microsystem of claim 41, wherein the microclamp comprises conductive doped polycrystalline silicon.

43. The microsystem of claim 40, wherein the actuator comprises materials selected from the group consisting of polymers, polysilicon, and metal, and combinations thereof.

44. The microsystem of claim 37, wherein the modular chip comprises a mating hole to accept the microclamp.

45. The microsystem of claim 34, wherein the modular chip is connectable to the substrate by a substantially liquid-leak-proof connection.

46. The microsystem of claim 34, wherein the substrate further comprises one or more holes in fluid connection with the microdconduits, and wherein the modular chip further comprises one or more male connectors adapted for fluid connection to the holes.

47. The microsystem of claim 34, wherein the modular chip contains a drug.

48. The microsystem of claim 34, wherein the modular chip contains one, or therapeutic or putative therapeutic agents.

49. A method for fabricating a modular chip comprising a back side and one or more male connectors, the method comprising:

etching the chip to generate one or more holes;

oxidizing the chip to generate an oxidized layer forming a capillary tube around at least one of the holes; and

etching the back side of the chip to preferentially expose the capillary tube of the male connector.

50. A microsystem comprising:

a substrate; and

one or more electrical flex cables electrically connected to the substrate at a proximal end and flexibly free at a distal end.

51. The microsystem of claim 50, wherein at least one of the electrical flex cables is integrally manufactured on the substrate.

52. The microsystem of claim 50, wherein the distal end of at least one flex cable is adapted for connection to a biological environment.

53. The microsystem of claim 50, wherein the distal end of at least one flex cable is adapted for connection to another microsystem.

54. The microsystem of claim 50, wherein the flexibility of at least one cable is constrained to inhibit entanglement of the flex cables.

55. The microsystem of claim 50, wherein at least one flex cable is twistable.

56. The microsystem of claim 50, wherein at least one flex cable is bendable away from the substrate.

57. The microsystem of claim 50, wherein the substrate further comprises one or more bond pads.

58. The microsystem of claim 50, further comprising a flip chip connected to the microsystem.

59. The microsystem of claim 50, wherein the distal end of at least one flex cable is adapted for connection to a microprocessor.

60. The microsystem of claim 50, wherein the distal end of at least one flex cable is adapted for connection to a flip chip.

61. The microsystem of claim 50, wherein the distal end of at least one flex cable is adapted for connection to a chip comprising a chip connection scheme selected from the group consisting of:

IBM'"'"'s C4 process, Tessera'"'"'s chip scale packaging, Quad Flat Pack and Ball Grid Array.

62. The microsystem of claim 50, further comprising a microprocessor modularly connected to the substrate.

63. The microsystem of claim 62, wherein the microprocessor is modularly connected to the substrate by one or more means selected from the group consisting of flip chip bonding, backside contacts and chip-scale packaging.

64. The microsystem of claim 62, wherein the microprocessor enables one or more in vivo functions selected from the group consisting of calibration, signal processing, signal storage and data storage.

65. A method of fabricating an electrical flex cable integral to a substrate at a proximal end and free at a distal end, the method comprising:

layering a sacrificial layer on the substrate;

depositing a patterned dielectric layer on the sacrificial layer;

depositing a patterned conductive layer on the dielectric layer;

depositing a capping dielectric layer on the conductive layer, wherein the capping layer is patterned to open windows; and

etching the sacrificial layer to release the patterned conductive layer from the substrate, thereby forming a flexible, electrically-conductive wire that is integral to the substrate at a proximal end and flexibly free from the substrate at a distal end.

66. The method of claim 65, wherein the substrate is selected from the group consisting of silicon, silicon on insulator, plastic, laminate and glass.

67. The method of claim 65, wherein the patterned dielectric layer is deposited on the sacrificial layer by CVD depositing or by spin coating.

68. The method of claim 65, wherein the conductive layer is selected from one or more of the materials in the group consisting:

of metal, gold, platinum and titanium.

69. The method of claim 65, wherein the conductive layer is deposited by sputtering or by direct evaporation onto the dielectric layer.

70. The method of claim 65, wherein the conductive layer is patterned by wet or dry etching.

71. The method of claim 65, wherein the total thickness of the flex cable is from approximately 1 to approximately 10 microns.

72. The method of claim 65, wherein the sacrificial layer is removed by dilute HF or by plasma etching.

73. The method of claim 65, further comprising treating the distal ends of the flex cable with one or more agents for sensing one or more biological signals whereby at least one signal is transmitted by the flex cable to the substrate for detection or analysis.

74. The method of claim 65, further comprising equipping the distal ends of the flex cables with one or more sensors selected from the group consisting of:

electrical capacitance sensors, pressure sensors, temperature sensors, thermistors and pH sensors.

75. The method of claim 65, wherein the flex cables further comprises a bond pad with either solder or indium bumps, wherein the method further comprises making an electrical connection with the flex cable by placing the bond pad of the flex cable on to an opposing bond pad;

and adhering the flex cable bond pad to the opposing bond pad, whereby an electrical connection is made between the substrate of the flex cable and the opposing bond pad.

76. A microsystem comprising:

a substrate; and

one or more flexible conduits integral with the substrate at a proximal end and free from the substrate at a distal end, wherein at least one conduit further comprises;

a fluid passageway having one or more passageway walls; and

an electrically conductive layer forming at least a portion of at least one of the passageway walls.

77. The microsystem of claim 76, wherein the distal end of the conduit either comprises a pH sensor or is adapted for connection to a pH sensor, and wherein the fluid passageway supplies pH buffer solution to the pH sensor.

78. The microsystem of claim 76, wherein fluid in the passageway is released by removing of at least a portion of the conductive layer.

79. The microsystem of claim 78, wherein the released portion of the conductive layer is removed by electrodissolution.

80. The microsystem of claim 78, wherein release of fluid from the passageway is programmed.

81. The microsystem of claim 80, wherein the programmed release of fluid is used to administer therapeutic agents in accordance with a programmed schedule.

82. The microsystem of claim 81, wherein the therapeutic agents treat AIDS or HIV infection.

83. The microsystem of claim 78, wherein the microsystem delivers PCR products in vivo or in vitro for gene therapy or gene manipulation.

84. The microsystem of claim 76, further comprising an intermediate layer between the conductive layer and the fluid passageway to form a membrane pump.

85. A microsystem comprising:

a substrate further comprising a body portion and one or more wafer portions; and

one or more flexible electrofluidic cables, wherein each cable is integral to the body portion of the substrate at a proximal end and is integral to at least one wafer portion of the substrate at a distal end, wherein the wafer portion of the substrate is detachable from the body portion of the substrate.

86. The microsystem of claim 85, wherein the body portion of the substrate further comprises one or more microdevices or sensors connected to the wafer portion by the electrofluidic cables.

87. The microsystem of claim 85, wherein the wafer portion is electrically insulated from the body portion of the substrate.

88. The microsystem of claim 85, wherein the wafer portion further comprises one or more microdevices or sensors.

89. The microsystem of claim 88, wherein the wafer portion is adapted for placement in a biological system.

90. The microsystem of claim 89, wherein the wafer portion performs electromechanical and chemical functions in the biological environment.

91. The microsystem of claim 90, wherein the microsystem administers or monitors medical agents for anesthesia or asthma.

92. The microsystem of claim 90, wherein the one or more microdevices further comprises microsurgical tools, and wherein the microsystem further comprises fluid circuit bypass systems for debris removal;

whereby the microsystem is adapted for removing arterial plaque or other undesired tissues from the biological system.