Method of making a polymer based circuit

• US 5,987,739 A
• Filed: 02/05/1996
• Issued: 11/23/1999
• Est. Priority Date: 02/05/1996
• Status: Expired due to Term

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Communications, Inc. (Micron Technology, Inc.)
• Inventors: Lake, Rickie Charles
• Primary Examiner(s): ECHOLS, PERCY W
• Application Number:
  US08/596,472
• Time in Patent Office: 1,387 Days
• Field of Search: 29/832, 29/840, 29/841, 29/846, 427/553, 427/554, 427/555, 427/412.5, 427/558
• US Class Current: 29/841
• CPC Class Codes: H01L 21/4803 Insulating or insulated parts, e.g. mountings, containers, diamond heatsinks H01L21/4846 takes precedence; printed circuit boards H05K1/00
• CPC Class Codes: H01L 23/145 Organic substrates, e.g. plastic
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 2201/0145 Polyester, e.g. polyethylene terephthalate [PET], polyethylene naphthalate [PEN]
• CPC Class Codes: H05K 3/28 Applying non-metallic protective coatings H05K3/0091 takes precedence; methods for intermediate insulating layers for build-up multilayer circuits H05K3/4673
• CPC Class Codes: H05K 3/284 for encapsulating mounted components H05K1/185 takes precedence
• CPC Class Codes: H05K 3/381 by special treatment of the substrate
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49146 with encapsulating, e.g., potting, etc.
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

A polymer based circuit production method provides a polymer based circuit by exposing a surface of a polymer substrate to ultraviolet radiation resulting in an adhesion promoted polymer substrate surface. A circuit is fabricated on the polymer substrate surface and a coating material is applied to at least a portion of the adhesion promoted polymer substrate surface. A portion of the circuit fabricated on the polymer substrate surface may be encapsulated. The polymer based circuit resulting from the method includes a polymer substrate having an ultraviolet radiation treated surface, a circuit formed on the polymer substrate surface, and a coating material encapsulating at least a portion of the at least one circuit between the polymer substrate and the coating material.

Claims

1. A polymer based circuit production method comprising the steps of:

treating a surface of a polymer substrate with ultraviolet radiation by directing the ultraviolet radiation in a region proximate the polymer substrate surface in the absence of a flow of ozone being supplied into the region the treatment resulting in an ultraviolet radiation treated polymer substrate surface for promoting adhesion of the surface to a coating material;

forming at least one circuit on the polymer substrate surface; and

applying the coating material to at least a portion of the ultraviolet radiation treated polymer substrate surface.

2. The method according to claim 1, wherein the application step includes the step of encapsulating at least a portion of the circuit fabricated on the polymer substrate surface.

3. The method according to claim 1, wherein the polymer substrate is a polyester film.

4. The method according to claim 3, wherein the polyester film includes a print treated polyester film.

5. The method according to claim 1, wherein the treating step comprises the step of exposing the polymer substrate surface to ultraviolet radiation one or more times for a total exposure time of less than a minute.

6. The method according to claim 5, wherein the polymer substrate surface is exposed to UV radiation in a range of about 50 mJ/cm² UV total exposure with a UV peak greater than about 50 mW/cm² to a UV total exposure of about 5 J/cm² with a UV peak of greater than about 50 mW/cm².

7. The method according to claim 5, wherein the polymer substrate surface is exposed to UV radiation in a range of about 50 mJ/cm² UV total exposure to a UV total exposure of about 5 J/cm².

8. The method according to claim 1, wherein the ultraviolet radiation is in the range of about 300 to about 450 nanometer wavelength.

9. The method according to claim 1, wherein the treating step further comprises the steps of:

positioning the polymer substrate on a belt;

operating a lamp in a range of about 50 watts per linear inch to about 600 watts per linear inch of the belt; and

moving the belt such that the polymer substrate surface is exposed to the ultraviolet radiation.

10. The method according to claim 1, wherein the application step includes applying the coating material in a predefined pattern on the polymer substrate surface.

11. The method according to claim 1, wherein the application step includes globbing the coating material over individual components of the at least one circuit.

12. A polymer based circuit production method comprising the steps of:

treating a surface of a polymer substrate with ultraviolet radiation by directing the ultraviolet radiation in a region proximate the polymer substrate surface in the absence of a flow of ozone being supplied into the region, the treatment resulting in an ultraviolet radiation treated polymer substrate surface for promoting adhesion of the surface to an epoxy;

forming at least one circuit on the polymer substrate surface;

applying the epoxy to at least a portion of the ultraviolet radiation treated polymer substrate surface, and

curing the epoxy to a hardness greater than about 30, Shore D.

13. The method according to claim 12, wherein the epoxy when cured has a hardness greater than about 60, Shore D.

14. The method according to claim 13, wherein the epoxy when cured has a hardness more preferably in the range of about 80 to about 90, Shore D.

15. A method according to claim 12, wherein the exposure of the polymer substrate surface results in an adhesion level between the polymer substrate surface and the epoxy, the adhesion level increasing with the number of times the polymer substrate surface is exposed to the ultraviolet radiation.

16. A polymer based circuit production method comprising the steps of:

treating a surface of a polymer substrate with ultraviolet radiation by directing the ultraviolet radiation in a region proximate the polymer substrate surface in the absence of a flow of ozone being supplied into the region the treatment resulting in an ultraviolet radiation treated polymer substrate surface for promoting adhesion of the surface to a coating material;

forming at least one circuit on the polymer substrate surface, wherein the circuit formation step includes;

forming a conductive trace on the polymer substrate surface; and

mounting circuit components on the polymer substrate surface in electrical communication with the conductive trace to form the at least one circuit; and

applying the coating material to at least a portion of the ultraviolet radiation treated polymer substrate surface, wherein the coating material application step includes;

forming a barrier on the polymer substrate surface to define at least one cavity surrounding at least a portion of the at least one circuit; and

depositing the coating material in the at least one cavity such that the components in the at least one cavity are encapsulated between the polymer substrate and the coating material.

17. The method according to claim 16, wherein the coating material is an epoxy in a viscous state when placed in the cavity and the application step further includes the step of curing the epoxy.

18. The method according to claim 16, wherein the at least one circuit includes a plurality of separate circuits, the barrier being positioned on the polymer substrate to form a cavity surrounding one or more of the plurality of separate circuits.

19. The method according to claim 16, wherein the barrier is positioned on the polymer substrate to form a cavity individually surrounding one or more of the electrical components.

20. A polymer based circuit production method comprising the steps of:

treating a surface of a polymer substrate with ultraviolet radiation by directing ultraviolet radiation in a region proximate the polymer substrate surface in the absence of a flow of ozone gas being supplied into the region, the treatment resulting in an ultraviolet radiation treated polymer substrate surface for promoting adhesion of the surface to a coating material;

forming at least one circuit on the polymer substrate surface;

applying the coating material to at least a portion of the ultraviolet radiation treated polymer substrate surface to encapsulate at least a portion of the circuit; and

curing the coating material to a hardness greater than about 30, Shore D.

21. The method according to claim 20, wherein the treating step comprises exposing the polymer substrate surface to ultraviolet radiation one or more times for less than a minute of total exposure time, ultraviolet radiation.

22. The method according to claim 21, wherein the polymer substrate surface is exposed to UV radiation in a range of about 50 mJ/cm² UV total exposure with a UV peak greater than about 50 mW/cm² to a UV total exposure of about 5 J/cm² with a UV peak of greater than about 50 mW/cm².

23. The method according to claim 21, wherein the ultraviolet radiation is in the range of about 340 to about 450 nanometer wavelength.

24. The method according to claim 23, wherein the ultraviolet radiation is in the range of about 340 nanometers to about 380 nanometers wavelength.

25. The method according to claim 21, wherein the exposing step further comprises the steps of:

positioning the polymer substrate on a belt of a UV radiation system;

defocusing a lamp operating in a range of about 50 watts per linear inch to about 600 watts per linear inch of the belt at about one inch in the direction of belt travel; and

moving the belt such that the polymer substrate surface is exposed to the ultraviolet radiation.

26. A polymer based circuit production method comprising the steps of:

exposing a surface of a polymer substrate to ultraviolet radiation in ambient air atmosphere one or more times for less than a minute of total exposure time resulting in an ultraviolet radiation treated polymer substrate surface for promoting adhesion of the surface to a coating material wherein exposing the surface includes continuously moving the surface through a UV radiation system such that the polymer substrate surface is exposed to the ultraviolet radiation;

forming at least one circuit on the polymer substrate surface; and

applying the coating material to at least a portion of the ultraviolet radiation treated polymer substrate surface to encapsulate at least a portion of the circuit.

27. The method according to claim 26, wherein the epoxy when cured has a hardness greater than about 30, Shore D.

28. The method according to claim 26, wherein the polymer substrate surface is exposed to UV radiation in a range of about 50 mJ/cm² UV total exposure with a UV peak greater than about 50 mW/cm² to a UV total exposure of about 5 J/cm² with a UV peak of greater than about 50 mW/cm².

29. The method according to claim 26, wherein the ultraviolet radiation is in the range of about 340 to about 450 nanometer wavelength.

30. The method according to claim 29, wherein the ultraviolet radiation is in the range of about 340 nanometers to about 380 nanometers wavelenth.

31. The method according to claim 26, wherein the exposing step further comprises the steps of:

positioning the polymer substrate on a belt of a UV radiation system;

operating a lamp in a range of about 50 watts per linear inch to about 600 watts per linear inch of the belt; and

moving the belt such that the polymer substrate surface is exposed to the ultraviolet radiation.

32. A polymer based circuit production method comprising the steps of:

exposing a surface of a polymer substrate to ultraviolet radiation having a wavelength in the range of about 340 to about 450 nanometers, the exposure resulting in an ultraviolet radiation treated polymer substrate surface for promoting adhesion of the surface to a coating material;

forming at least one circuit on the polymer substrate surface; and

applying the coating material to at least a portion of the ultraviolet radiation treated polymer substrate surface.

33. The method according to claim 32, wherein the wavelength is in the range of about 340 nanometers to about 380 nanometers.

34. The method according to claim 32, wherein the exposing step comprises exposing the polymer substrate surface to ultraviolet radiation one or more times for less than a minute of total exposure time.

35. The method according to claim 34, wherein the polymer substrate surface is exposed to UV radiation in a range of about 50 mJ/cm² UV total exposure to a UV total exposure of about 5 J/cm².

36. The method according to claim 34, wherein the exposing step further comprises the steps of:

positioning the polymer substrate on a belt of a UV radiation system;

operating a lamp in a range of about 50 watts per linear inch to about 600 watts per linear inch of the belt; and

moving the belt such that the polymer substrate surface is exposed to the ultraviolet radiation.

37. The method according to claim 32, wherein the application step includes encapsulating at least a portion of the circuit by applying an epoxy to at least a portion of the ultraviolet radiation treated polymer substrate surface.

38. The method according to claim 37, wherein the epoxy when cured has a hardness greater than about 30, Shore D.

39. A polymer based circuit production method comprising the steps of:

directing ultraviolet radiation at a surface of a polymer substrate resulting in an ultraviolet radiation treated polymer substrate surface for promoting adhesion of the surface to a coating material, wherein the polymer substrate surface is exposed to a total UV radiation exposure greater than about 50 mJ/cm² ;

forming at least one circuit on the polymer substrate surface; and

applying the coating material to at least a portion of the ultraviolet radiation treated polymer substrate surface.

40. The method according to claim 39, wherein the total UV radiation exposure is in the range of about 50 mJ/cm² UV with a UV peak greater than about 50 mW/cm² to a UV total exposure of about 5 J/cm² with a UV peak of greater than about 50 mW/Cm².

41. The method according to claim 39, wherein the total UV radiation exposure is in a range of about 50 mJ/cm² UV total exposure to a UV total exposure of about 5 J/cm².

42. The method according to claim 39, wherein the wavelength of the ultraviolet radiation is in the range of about 340 to about 450 nanometers.