Method of manufacturing passive elements using conductive polypyrrole formulations

• US 5,948,232 A
• Filed: 06/23/1997
• Issued: 09/07/1999
• Est. Priority Date: 06/19/1995
• Status: Expired due to Fees

• Current Assignee: Lynntech Incorporated
• Original Assignee: Lynntech Incorporated
• Inventors: Hodko, Dalibor, Murphy, Oliver J., Miller, David L., Hitchens, G. Duncan, Clarke, Eric T., Parker, Donald L.
• Primary Examiner(s): Gorgos, Kathryn
• Assistant Examiner(s): Wong, Edna
• Application Number:
  US08/881,107
• Time in Patent Office: 806 Days
• Field of Search: 204/157.15, 205/125, 205/163, 205/164, 205/183, 205/162, 205/224, 205/122, 205/166, 427/508, 427/510, 427/512, 427/518, 427/520, 429/25.03
• US Class Current: 205/122
• CPC Class Codes: C08G 61/124 with a five-membered ring containing one nitrogen atom in the ring
• CPC Class Codes: C23C 26/00 Coating not provided for in groups C23C2/00 - C23C24/00
• CPC Class Codes: C25D 5/56 of plastics
• CPC Class Codes: G03F 7/0045 with organic non-macromolecular light-sensitive compounds not otherwise provided for, e.g. dissolution inhibitors
• CPC Class Codes: G03F 7/027 Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds G03F7/075 takes precedence
• CPC Class Codes: H01B 1/12 organic substances organic macromolecular compounds or compositions C08
• CPC Class Codes: H01C 17/242 by laser trimming by laser in general B23K26/351
• CPC Class Codes: H01C 7/005 Polymer thick films
• CPC Class Codes: H01G 9/025 Solid electrolytes H01G11/54 takes precedence
• CPC Class Codes: H05K 1/095 for polymer thick films, i.e. having a permanent organic polymeric binder
• CPC Class Codes: H05K 1/162 incorporating printed capacitors
• CPC Class Codes: H05K 1/165 incorporating printed inductors
• CPC Class Codes: H05K 1/167 incorporating printed resistors
• CPC Class Codes: H05K 2201/0329 Intrinsically conductive polymer [ICP]; Semiconductive polymer
• CPC Class Codes: H05K 2203/0514 Photodevelopable thick film, e.g. conductive or insulating paste
• CPC Class Codes: H05K 3/105 by conversion of non-conductive material on or in the support into conductive material, e.g. by using an energy beam
• CPC Class Codes: H05K 3/424 by direct electroplating

Abstract

The present invention provides electronically conducting polymer films formed from formulations of pyrrole and an electron acceptor. The formulations may include photoinitiators, flexibilizers, solvents and the like. These formulations can be used to manufacture multichip modules on typical multichip module substrates, such as alumina, fiberglass epoxy, silicon and polyimide. The formulations and methods of the invention enable the formation of passive electronic circuit elements such as resistors, capacitors and inductors in multichip modules or printed wiring boards.

Claims

1. A method of making a passive element on a surface, comprising the steps of:

(a) applying a film of a formulation onto the surface;

(b) forming an electronically conducting polymer between two points on the formulation; and

(c) removing the formulation adjacent the polymer.

2. A method comprising the steps of:

(a) applying a formulation onto a surface;

(b) polymerizing a portion of the formulation to form an electronically conducting polymer; and

(c) removing the formulation adjacent the polymer.

3. The method of claim 2,

wherein a resistor is formed between two points, and the method further comprises the steps of:

(d) trimming the resistor;

(e) measuring resistance between the two points; and

(f) repeating steps (d) and (e).

4. The method of claim 3, wherein the step of trimming the resistor increases the resistance of the resistor.

5. The method of claim 2, further comprising the steps of:

(d) trimming the polymer;

(e) measuring the resistance of the polymer; and

(f) repeating steps (d) and (e) until a desired resistance is obtained.

6. The method of claim 2, wherein the step of polymerizing is done by photopolymerizing.

7. A method of forming an electronically conducting polymer on a surface comprising the steps of:

(a) applying a formulation in the form of a liquid solution containing one or more metal cations onto the surface;

(b) polymerizing a first plurality of lines in the formulation to form a first part of an inductor,

(c) applying additional formulation over the first plurality of lines and the surface; and

(d) polymerizing a second plurality of lines in the additional formulation.

8. The method of claim 7 further comprising the step of:

(e) depositing a layer of dielectric material over the first film prior to applying the additional formulation.

9. The method of claim 8 further comprising the step of:

(f) forming holes through the layer of dielectric material and into communication with ends of at least two of the first plurality of lines prior to applying the additional formulation;

wherein ends of each of the second plurality of lines are in electrical communication with ends of each of the first plurality of lines, and the first plurality of lines and the second plurality of lines cooperate to form a conducting pathway.

10. The method of claim 7 wherein the step of polymerizing is done by photopolymerizing.

11. A method of forming an electronically conducting polymer on a conducting or nonconducting surface comprising the steps of:

(a) applying a film of a formulation onto the surface, wherein the formulation comprises pyrrole, Ag⁺ cations, aniline and a dopant anion selected from the group consisting of NO₃^-, NO₂^-, BF₄^-, ClO₄^-, tosylate, and mixtures thereof; and

(b) polymerizing a portion of the film to form the polymer.

12. The method of claim 11 wherein a pyrrole:

Ag⁺ cation molar ratio is greater than about 0.5, and a pyrrole;

dopant anion molar ratio is greater than about 0.5.

13. The method of claim 11 wherein a pyrrole:

Ag⁺ cation molar ratio in the formulation is between about 0.5 and about 20, and a pyrrole;

dopant anion molar ratio is between about 0.5 and about 20.

14. The method of claim 11 wherein the formulation further comprises a comonomer, and wherein a pyrrole:

comonomer molar ratio is between about 1 and about 100.

15. The method of claim 11 wherein the film further comprises an initiator.

16. The method of claim 15 wherein the film further comprises a surfactant.

17. The method of claim 11 wherein the formulation further comprises a solvent, and the method further comprises the step of allowing a substantial amount of the solvent to evaporate from the film before polymerizing.

18. The method of claim 11 further comprising the step of heating the polymer to provide a post-thermal cure at a temperature of between about 25 and about 100 degrees Celsius for between about 0.1 and about 3 hours.

19. The method of claim 11 wherein the film is selectively polymerized by direct laser imaging.

20. The method of claim 19 wherein the laser light has a wavelength between about 457 and about 1060 nanometers.

21. The method of claim 11 wherein the film is selectively polymerized by an electron beam.

22. The method of claim 11 wherein the film is applied by spin coating at between about 250 and about 2,000 rotations per minute.

23. The method of claim 11, wherein the Ag⁺ cations and the dopant anion are provided in the formulation as a salt, and wherein a pyrrole:

salt molar ratio is greater than about 0.5.

24. The method of claim 11 wherein a pyrrole:

Ag⁺ cation molar ratio is greater than about 0.5.

25. The method of claim 11 wherein a pyrrole:

dopant anion molar ratio is greater than about 0.5.

26. The method of claim 11 wherein a pyrrole:

Ag⁺ cation molar ratio in the formulation is between about 0.5 and about 20.

27. The method of claim 11 wherein a pyrrole:

dopant anion molar ratio is between about 0.5 and about 20.

28. The method of claim 11 further comprising the step of:

(c) increasing the resistance of the polymer by trimming the polymer.

29. The method of claim 28 further comprising the steps of:

(d) measuring the resistance of the polymer; and

(e) repeating steps (c) and (d).

30. The method of claim 29 wherein step (e) is performed until a desired resistance is obtained.

31. The method of claim 28 wherein a laser is used in step (c) for trimming the polymer.

32. The method of claim 11 wherein directed laser light is used to perform the polymerizing step.

33. The method of claim 11 wherein ultraviolet light is used to perform the polymerizing step.

34. The method of claim 11 wherein an electron beam is used to perform the polymerizing step.

35. A method of forming an electronically conducting polymer resistor on a conducting or nonconducting substrate surface comprising the steps of:

(a) applying a film of a formulation comprising pyrrole monomer and a salt onto the substrate surface, the salt consisting essentially of Ag⁺ cations, aniline and dopant anions selected from the group consisting of NO₃^-, NO₂^-, BF₄^-, ClO.sub.^-, tosylate, and mixtures thereof; and

(b) polymerizing a portion of the film to form the resistor.

36. The method of claim 35 further comprising the steps of:

(c) measuring the resistance of the resistor;

(d) increasing the resistance of the resistor by trimming the resistor with a laser; and

(e) repeating steps (c) and (d) until a desired resistance is obtained.

37. The method of claim 35, further comprising the step of:

(c) removing the formulation adjacent the resistor.

38. The method of claim 37, further comprising the step of:

(d) heating the resistor to provide a post-thermal cure.

39. The method of claim 38 wherein the resistor is cured at a temperature of between about 25 and about 100 degrees Celsius for between about 0.1 and about 3 hours.

40. The method of claim 38, further comprising the step of:

(e) trimming the resistor with a laser.

41. The method of claim 40, further comprising the steps of:

(f) measuring the resistance of the resistor; and

(g) increasing the resistance of the resistor by trimming the resistor with a laser.

42. The method of claim 41, further comprising the step of:

(h) repeating steps (f) and (g) until a desired resistance is measured.

43. A method of forming an electronically conducting polymer resistor on a conducting or nonconducting substrate surface comprising the steps of:

(a) applying a film of a formulation comprising pyrrole monomer and a salt onto the substrate surface, wherein the salt is an electron acceptor consisting essentially of AgNO₃ and dopant anions selected from the group consisting of NO₃^-, NO₂^-, BF₄^-, ClO₄^-, tosylate, and mixtures thereof; and

(b) directing laser light onto the film to polymerize a specified area of the film.

44. The method of claim 43, wherein the laser light is directed through a condensing lens to form a beam having a width of about 150 micrometers.

45. The method of claim 44, further comprising the step of:

(c) rastering the beam to polymerize the specified area of the film.

46. A method of forming an electronically conducting polymer on a conducting or nonconducting surface comprising the steps of:

(a) applying a film of a formulation comprising pyrrole monomer and a salt onto the surface, wherein the salt consists of an electron acceptor containing Ag⁺ cations aniline, and a dopant anion selected from the group consisting of NO₃^-, NO₂^-, BF₄^-, ClO₄^-, tosylate, and mixtures thereof; and

(b) polymerizing a portion of the film to form the polymer.

47. The method of claim 46, wherein the polymer is polymerized by direct laser imaging.

48. The method of claim 47, wherein the direct laser imaging is performed using a continuous wave argon-ion laser.

49. The method of claim 47, wherein the direct laser imaging is performed at a beam power of between about 300 and about 400 milliwatts.

50. The method of claim 47, wherein the direct laser imaging is performed by a laser beam moving at a linear velocity of between about 2 and about 16 millimeters per minute.

51. A method of forming a plurality of electronically conducting polymer resistors having different electrical resistances on a common substrate surface, the method comprising the steps of:

(a) preparing a plurality of formulations comprising a monomer and a salt, wherein the salt consists of Ag⁺ cations and a dopant anion selected from the group consisting of NO₃^-, NO₂^-, BF₄^-, ClO₄^-, tosylate, and mixtures thereof, and wherein each of the formulations has a different molar concentration of salt;

(b) applying a film of at least one of the plurality of formulations onto the substrate surface;

(c) polymerizing a portion of the film to form a resistor, wherein the polymerized portion extends between two contact points and has sufficient thickness and width so that the overall electrical resistance between the two contact points is somewhat less than a resistance specified for that resistor;

(d) removing the formulation adjacent the resistor;

(e) repeating steps (b) through (d) for each of the plurality of formulations; and

(f) heating the resistor to provide a thermal cure.

52. The method of claim 51 wherein the monomer is pyrrole and the salt is silver nitrate.

53. A method of forming an electronically conducting polymer inductor on a nonconducting substrate surface comprising the steps of:

(a) preparing a formulation;

(b) applying a first film of the formulation onto the substrate surface;

(c) polymerizing a plurality of lower lines in the film;

(d) removing the formulation adjacent the lines;

(e) depositing a layer of dielectric material over the lower lines, wherein the layer forms a top surface;

(f) forming holes through the layer of dielectric material and into communication with ends of at least two lower lines;

(g) applying the formulation to the holes and top surface of the dielectric material to form a second film over the top surface; and

(h) selectively polymerizing the second film to form vertical paths and upper lines, wherein ends of each upper line connect with the vertical paths, and wherein the upper lines, lower lines and vertical paths are electronically conducting and cooperate to form a conductive pathway.

54. The method of claim 53, wherein the formulation comprises a monomer and a silver salt, the silver salt comprising Ag⁺ cations and dopant anions selected from the group consisting of NO₃^-, NO₂^-, BF₄^-, ClO₄^-, tosylate, and mixtures thereof.

55. The method of claim 54, wherein the monomer is selected from the group consisting of pyrrole, aniline, and mixtures thereof.

56. The method of claim 54, wherein the monomer is selected from the group consisting of pyrrole, substituted derivatives of pyrrole, aniline, substituted derivatives of aniline, and mixtures thereof.

57. A method of forming a solid state electrolytic capacitor in which a conducting polymer is applied as an electrolyte comprising the steps of:

(a) applying a film of a formulation on a surface, wherein the formulation comprises pyrrole, aniline and an electron acceptor; and

(b) polymerizing a portion of the film for the purpose of forming a capacitor.

58. The method of claim 57, wherein the polymerizing step forms a polymer, the method comprising the further steps of:

(c) removing the formulation adjacent the polymer;

(d) depositing a layer of palladium onto the polymer by immersion in a solution consisting of a palladium containing salt; and

(e) electrodepositing a layer of a metal conductor.

59. The method of claim 58, wherein the formulation comprises a monomer and a silver salt, the silver salt comprising Ag⁺ cations and dopant anions selected from the group consisting of NO₃^-, NO₂^-, BF₄^-, ClO₄^-, tosylate, and mixtures thereof.

60. A method of forming a plurality of passive elements on a common conducting or nonconducting substrate surface comprising the steps of:

(a) preparing a formulation comprising a monomer and a salt, wherein the salt consists of an electron acceptor consisting of Ag⁺ cations and a dopant anion selected from the group consisting of NO₃^-, NO₂^-, BF₄^-, ClO₄^-, tosylate, and mixtures thereof;

(b) forming an electronically conducting polymer resistor on the substrate surface comprising the steps of;

(i) applying a film of the formulation onto the substrate surface;

(ii) polymerizing a portion of the film to form a resistor; and

(iii) removing the formulation adjacent the resistor;

(c) forming a solid state electrolytic capacitor on the substrate surface in which a conducting polymer is applied as an electrolyte comprising the steps of;

(i) applying a film of the formulation on a dielectric layer on the surface;

(ii) polymerizing a portion of the film to form a polymer;

(iii) removing the formulation adjacent the polymer;

(iv) depositing a layer of palladium onto the surface of the polymer by immersion in a palladium salt solution; and

(v) electrodepositing a layer of a metal conductor; and

(d) forming an electronically conducting polymer inductor on the substrate surface comprising the steps of;

(i) applying a film of the formulation onto the substrate surface;

(ii) polymerizing a plurality of lower lines in the film;

(iii) removing the formulation adjacent the lines;

(iv) depositing a layer of dielectric material over the lower lines wherein the layer forms a top surface;

(v) forming holes through the layer of dielectric material and into communication with ends of at least two lower lines;

(vi) applying the formulation to the holes and top surface of the dielectric material to form a second film over the top surface; and

(vii) selectively polymerizing the second film to form vertical paths and upper lines, wherein ends of each upper horizontal line connect with the vertical paths, and wherein the upper lines, lower lines and vertical paths are electronically conducting and cooperate to form a conductive pathway.

61. A method of making a resistor on a substrate surface, comprising the steps of:

(a) forming an electronically conducting polymer between two points on the substrate surface; and

(b) trimming the polymer with a laser.

62. The method of claim 61, farther comprising the steps of:

(c) measuring the resistance between the two points; and

(d) repeating steps (b) and (c).

63. A method for selectively polymerizing a film of a polymerizable formulation comprising the steps of:

(a) directing laser light on the film of the polymerizable formulation to form a polymer; and

(b) rastering the light over a specified area of the film.

64. The method of claim 63, wherein the laser light is directed through a condensing lens to form a beam having a width of about 150 micrometers.

65. The method of claim 63, wherein the laser light is provided by a continuous wave argon-ion laser operating at a beam power of between about 300 and about 400 milliwatts.

66. The method of claim 63, wherein the light is moved over the film at a linear velocity of between about 2 and about 16 millimeters per minute.