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1. WO2007029132 - A METHOD OF MANUFACTURING A MICROSYSTEM, SUCH A MICROSYSTEM, A STACK OF FOILS COMPRISING SUCH A MICROSYSTEM, AN ELECTRONIC DEVICE COMPRISING SUCH A MICROSYSTEM AND USE OF THE ELECTRONIC DEVICE

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[ EN ]

CLAIMS:

1. A method of manufacturing a microsystem (MI, PS, AC, MV, MP, MT) provided with a space (110, 310, 510, 710, 910, 1110), which method comprises the following steps:
providing a set (S) of at least two electrically insulating flexible foils, wherein the individual foils have substantially the same thickness, and wherein a conductive layer is present on at least one side of at least one foil, and wherein said conductive layer is suitable for use as an electrode or a conductor;
patterning the conductive layer so as to form an electrode or a conductor;
patterning at least one foil, in such a manner that an opening is formed, which opening forms the space of the microsystem;
stacking the set (S) of foils, thus forming the microsystem; and
joining the foils together, with the foils being bonded together at those positions where, when two adjacent foils are in contact with each other, at least one conductive layer between the foil material of two adjacent foils has been removed.

2. A method as claimed in claim 1, characterized in that a set (S) of foils is provided, with the individual foils comprising the same foil material.

3. A method as claimed in any one of the preceding claims, characterized in that at least three electrically insulating flexible foils are provided.

4. A method as claimed in any one of the preceding claims, characterized in that a movable element is formed of at least one foil in the microsystem, which movable element is attached to the microsystem on at least one side, wherein the movable element is selected from the group comprising a movable mass (500), a movable valve (770, 955, 965) and a movable membrane (100, 200, 300, 900), and wherein the movable element is present on one side of the space.

5. A method as claimed in any one of the preceding claims, characterized in that the microsystem is provided with a sensor (1170, 1180) that is formed in a conductive layer on a foil near said space for measuring a quantity in said space.

6. A method as claimed in any one of the preceding claims, characterized in that the microsystem to be manufactured comprises an MEMS device.

7. A method as claimed in claim 6, characterized in that the microsystem that is manufactured is a microsystem from the group comprising an MEMS capacitor microphone (MI), an MEMS pressure sensor (PS), an MEMS accelerometer (AC).

8. A method as claimed in any one of the preceding claims, characterized in that the microsystem to be manufactured comprises a microfluidic device.

9. A method as claimed in claim 7, characterized in that the microsystem that is manufactured is a microsystem from the group comprising a microvalve (MV), a micropump (MP) and a μTAS element (MT).

10. A method as claimed in any one of the preceding claims, characterized in that said patterning is carried out by means of a laser (Ll, L2), whether or not in combination with a mask (20).

11. A method as claimed in claim 10, characterized in that said patterning is carried out by using a selection from the following steps:
- leaving the conductive layer (1 Ia) and the foil (10) in tact (A);
removing the conductive layer (Ha) so as to expose the foil (10) (B);
removing the conductive layer (lla) and part of the foil (10), so that a thinner foil remains (C); and
completely removing the conductive layer (l la, 1 Ib) and the foil so as to form the space (D).

12. A method as claimed in any one of the preceding claims, characterized in that said stacking of the foils takes place by winding at least one foil (10) onto a first reel (70).

13. A method as claimed in claim 12, characterized in that the method is carried out in a process in which the foil (10) is unwound from a second reel or roll (80) upon being wound onto the first reel (70).

14. A method as claimed in claim 13, characterized in that said patterning of the conductive layer (Ha) and the foil (10) takes place at at least one position selected from the following possibilities: on or near the first reel (Ll), between the first and the second reel (L2), and on or near the second reel or roll (80).

15. A method as claimed in any one of the preceding claims, characterized in that said joining of the foils is carried out by exerting a pressure on the stacked foils at an elevated temperature, with the pressure being exerted in a direction perpendicular to the foils.

16. A method as claimed in claim 15, characterized in that the required pressure on the foils adjacent to the space in the structure is obtained through the application of an elevated pressure in said space.

17. A method as claimed in any one of the preceding claims, characterized in that an opening (130, 135) is formed in the stack of foils so as to provide access from one side of the microsystem to a conductive layer (121) that is connected to an electrode of the microsystem.

18. A method as claimed in any one of the preceding claims, characterized in that the microsystem is separated from the stack after fusion of the foils has taken place.

19. A method as claimed in any one of the preceding claims, characterized in that the material for the conductive layer is selected from the group comprising aluminum, platinum, silver, gold, copper, indium tin oxide, and magnetic materials.

20. A method as claimed in any one of the preceding claims, characterized in that the foil material is selected from the group comprising polyphenyl sulphide (PPS) and polyethylene terephthalate (PET).

21. A method as claimed in any one of the preceding claims, characterized in that the foil (10) that is used has a thickness between 1 μm and 5 μm.

22. A microsystem (MI, PS, AC, MV, MP, MT) built up of a set (S) of at least two electrically insulating flexible foils stacked one on top of the other, wherein the individual foils have substantially the same thickness, wherein at least one foil is provided with a patterned conductive layer, which is arranged as an electrode, and wherein at least one foil is provided with a space (110, 310, 510, 710, 910, 1110).

23. A microsystem as claimed in claim 22, characterized in that the individual foils comprise the same foil material.

24. A microsystem as claimed in claim 22 or 23, characterized in that the microsystem comprises at least three electrically insulating flexible foils.

25. A microsystem as claimed in any one of the claims 22-24, characterized in that the microsystem comprises a movable element, which movable element comprises at least one foil and which is attached to the microsystem on at least one side, wherein the movable element has been selected from the group comprising a movable mass (500), a movable valve (770, 955, 965) and a movable membrane (100, 200, 300, 900), and wherein the movable element present at one side of the space.

26. A microsystem as claimed in any one of the claims 22-25, characterized in that said microsystem comprises a sensor (1170, 1180) which is implemented in a conductive layer on a foil near the space for measuring a quantity in said space.

27. A microsystem as claimed in claim 25, characterized in that said microsystem comprises an MEMS capacitor microphone (MI).

28. A microsystem as claimed in claim 27, characterized in that the set (S) of foils comprises at least three foils, with a space (110) being present in the microsystem, which space (110) is provided on a first side thereof with a first foil (100) arranged as a membrane for receiving sound waves, and which space (110) is provided on a second side thereof with a second foil (120) arranged as a backplate, which second foil comprises an opening (125) for the passage of pressure waves to a free space, which space (110) has a thickness, measured in a direction perpendicular to the foils, of at least one foil, and in that the microsystem is further characterized in that the membrane (100) and the backplate (120) are also provided with a conductive layer (102, 121), which layers (102, 121) lead to areas (130, 135) for electrically connecting the microsystem.

29. A microsystem as claimed in claim 28, characterized in that the foil of the membrane (100) or the backplate (120) is provided with a conductive layer (101, 102, 121, 122) on two sides.

30. A microsystem as claimed in claim 28 or 29, characterized in that the foil of the membrane (200) comprises areas (208) at the edges thereof which are thinner than the rest of the foil of the membrane.

31. A microsystem as claimed in claim 25, characterized in that said microsystem comprises an MEMS pressure sensor (PS).

32. A microsystem as claimed in claim 31, characterized in that said set (S) comprises at least three foils, with a first space (310) being present in the microsystem, which space (310) is provided on a first side thereof with a movable membrane (300) comprising a conductive layer (301) that functions as a first electrode, which membrane (300), on the other side thereof, is positioned adjacent to a further space in which the pressure to be measured prevails, wherein the first space (310) is provided on a second side thereof with a second electrode which is implemented in a conductive layer (321) on a foil (320), wherein said first electrode and said second electrode overlap when projected on a plane parallel to the foils, so that the first electrode and the second electrode jointly form a capacitance that depends on pressure differences (F) between said first space (310) and said further space, causing the membrane (300) to deflect, which microsystem is further characterized in that the first space (310) has a thickness, measured in a direction perpendicular to the foils, of at least one foil, said microsystem further being characterized in that the conductive layers (301, 321) of the electrode lead to areas (330, 335) for electrically connecting the microsystem.

33. A microsystem as claimed in claim 25, characterized in that said microsystem comprises an MEMS accelerometer (AC).

34. A microsystem as claimed in claim 23, characterized in that the set (S) comprises at least three foils, with a space (510) having a thickness of at least one foil being present in the microsystem, which space (510) is provided on a first side thereof with a first electrode (502) on a movable mass (500), which mass (500) is made up of a stack comprising at least one foil, and which mass (500) is connected to the microsystem via resilient connections (505), and wherein a second electrode (521) is present on an opposite side of the space (510), wherein both said first electrode (502) and said second electrode (521) are implemented in the conductive layer of or foil, wherein said first electrode (502) and said second electrode (521) overlap when projected on a plane parallel to the foils, so that said first electrode (502) and said second electrode (521) jointly form a capacitance, which capacitance depends on acceleration forces being exerted on the movable mass (500), which acceleration forces effect a relative movement of the mass (500) with respect to the microsystem, and thus a change in the thickness of the space (510) between the two electrodes, said microsystem further being characterized in that the conductive layers (502, 521) of the electrodes lead to areas (530, 535) for electrically connecting the microsystem.

35. A microsystem as claimed in claim 25, characterized in that said microsystem comprises a microvalve (MV).

36. A microsystem as claimed in claim 35, characterized in that the set (S) comprises at least four foils, with a space (710) having an inlet (750) and an outlet (760) being present in the microsystem, wherein at least the outlet (760) can be shut off by means of a movable valve (770) that is attached to the microsystem, said valve (770) comprising a foil provided with a conductive layer that defines a first electrode (771), and wherein the space (710) is provided on a first side thereof with a second electrode (701) and, on an opposite side, with a third electrode (722), wherein both said second electrode (701) and said third electrode (722) are implemented in an electrically conductive layer on a foil (700, 720), wherein all the electrodes (701, 722, 771) overlap when projected on a plane parallel to the foils, so that said second electrode (701) and said third electrode (722) can be used for driving the movable valve (770) capacitively, which microsystem is further characterized in that the space (710) has a thickness of at least one foil, measured in a direction perpendicular to the foils, said microsystem further being characterized in that the conductive layers (701, 722, 771) of the electrodes lead to areas (730, 735, 740) for electrically connecting the microsystem.

37. A microsystem as claimed in claim 25, characterized in that said microsystem comprises a micropump (MP).

38. A microsystem as claimed in claim 37, characterized in that the set (S) comprises at least six foils, with a first space (910) having an inlet (950) and outlet (960) being present in the microsystem, wherein both the inlet (950) and the outlet (960) can be shut off by means of a movable valve (955, 965) comprising a foil that is attached to the microsystem, and wherein said first space (910) is provided on a first side thereof with a movable membrane (900) comprising an electrically conductive layer (901) that defines a first electrode, which movable membrane is positioned adjacent to a second space (915) at an opposite side thereof, which second space (915) is provided on an opposite side thereof with a foil (925) comprising an electrically conductive layer (927) that functions as a second electrode and, wherein said first electrode (901) and said second electrode (927) overlap when projected on a plane parallel to the foils, so that the second electrode (927) can be used for driving the movable membrane (900) capacitively, which microsystem is further characterized in that the two spaces (910, 915) have a thickness of at least one foil, measured in a direction perpendicular to the foils, said microsystem further being characterized in that the conductive layers (901, 927) of the electrodes lead to areas (930, 940) for electrically connecting the microsystem.

39. A microsystem as claimed in claim 38, characterized in that the microsystem is furthermore provided with another conductive layer (922) on the foil (920) on a second side of the first space (910), which conductive layer (922) defines a third electrode, wherein said first electrode (901) and said third electrode (922) overlap when projected on a plane parallel to the foils, so that the third electrode (922) can also be used for driving the movable foil (900) capacitively, said microsystem further being characterized in that the conductive layer (922) of this electrode also leads to an area (935) for electrically connecting the microsystem.

40. A microsystem as claimed in claim 26, characterized in that said microsystem comprises a μTAS element (MT).

41. A microsystem as claimed in claim 40, characterized in that the set (S) comprises at least three foils, with a channel (1110) having an inlet (1150) and an outlet (1160) for the passage of a gas or a liquid therethrough being present in the microsystem, wherein the channel (1110) has a thickness of at least one foil, measured in a direction perpendicular to the foils, and wherein the channel (1110) is provided with a sensor or actuator (1170, 1180) on one side thereof.

42. A microsystem as claimed in claim 41, characterized in that said sensor or actuator is formed in the conductive layer of the foil adjacent to the channel.

43. A microsystem as claimed in claim 42, characterized in that said microsystem comprises a flow sensor (1170).

44. A microsystem as claimed in claim 42 or 43, characterized in that said microsystem comprises a conductivity sensor (1180).

45. A microsystem as claimed in any one of the claims 42-44, characterized in that said microsystem comprises a further sensor or actuator, which is present in a conductive layer of the foil adjacent to an opposite side of the channel (1110).

46. A microsystem as claimed in any one of the claims 22-45, characterized in that the material of the conductive layer comprises a metal from the group comprising aluminum, platinum, silver, gold, copper, indium tin oxide, and magnetic materials.

47. A microsystem as claimed in any one of the claims 22-46, characterized in that the material for the foils comprises a substance from the group comprising polyphenyl sulphide (PPS) and polyethylene terephthalate (PET).

48. A microsystem as claimed in any one of the claims 22-47, characterized in that the foil has a thickness between 1 μm and 5 μm.

49. A stack (S) of electrically insulating flexible foils comprising the microsystem as claimed in any one of the claims 27-34.

50. An electronic device comprising the microsystem as claimed in any one of the claims 27-34.

51. An electronic device as claimed in claim 50, characterized in that said electronic device furthermore comprises an integrated circuit (IC) for reading or driving a signal from the microsystem.

52. An electronic device as claimed in claim 51, characterized in that the microsystem is provided with a recess (1205), in which the integrated circuit (IC) is accommodated, so that the microsystem in fact forms part of the package of the integrated circuit (IC), which integrated circuit (IC) is connected to the microsystem.

53. Use of the electronic device as claimed in any one of the claims 50-52, characterized in that the microsystem comprises an MEMS capacitor microphone (MI) for recording sound, wherein the MEMS capacitor microphone delivers a voltage X on electrodes and wherein the voltage X is read by the integrated circuit (IC).