Circuitry interconnection method

• US 6,251,211 B1
• Filed: 07/22/1998
• Issued: 06/26/2001
• Est. Priority Date: 07/22/1998
• Status: Expired due to Term

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Lake, Rickie C.
• Primary Examiner(s): Ball, Michael W.
• Assistant Examiner(s): Tolin, Michael A
• Application Number:
  US09/120,849
• Time in Patent Office: 1,070 Days
• Field of Search: 156/273.3, 156/275.1, 156/275.3, 156/275.7, 257/737, 257/738, 257/778, 257/781, 257/783, 438/108, 438/119, 438/127, 298/32, 298/41, 361/767, 361/768, 361/771
• US Class Current: 156/273.3
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/0775 arrangements for connecting the integrated circuit to the antenna
• CPC Class Codes: H01L 2224/13 of an individual bump connector
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/81801 Soldering or alloying
• CPC Class Codes: H01L 24/10 Bump connectors bumps on insulating substrates, e.g. chip carriers, H01L23/49816; Manufacturing methods related thereto
• CPC Class Codes: H01L 24/13 of an individual bump connector
• CPC Class Codes: H01L 24/81 using a bump connector
• 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 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H05K 2201/0367 Metallic bump or raised conductor not used as solder bump solder materials or compositions and methods of application thereof H05K3/3457
• CPC Class Codes: H05K 2201/10674 Flip chip
• CPC Class Codes: H05K 2201/10992 Using different connection materials, e.g. different solders, for the same connection
• CPC Class Codes: H05K 3/321 by conductive adhesives
• 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.

Abstract

Electrically conductive polymer bumps are formed in electrical connection with circuitry supported by a first substrate. The polymer bumps are bonded with a conductive adhesive to circuitry supported by a second substrate, with the conductive adhesive being in electrical connection with the circuitry supported by the second substrate. Prior to said bonding, an effective amount of ultraviolet radiation is impinged onto the polymer bumps to enhance adhesion of the bumps with the conductive adhesive and electrical conduction between the circuitry of the first substrate and the circuitry of the second substrate. In one implementation, ultraviolet radiation of at least 340 nm is impinged onto conductive polymer bumps prior to subsequent bonding. In one implementation, ultraviolet radiation is impinged onto conductive polymer bumps for a time period less than one minute prior to subsequent bonding. In one implementation, ultraviolet radiation is impinged onto conductive polymer bumps to provide a total ultraviolet radiation exposure of greater than about 50 mJ/cm² prior to subsequent bonding. In one implementation, ultraviolet radiation is impinged onto conductive polymer bumps in the absence of ozone other than any produced by said ultraviolet radiation prior to subsequent bonding. In one implementation, ultraviolet radiation is impinged onto conductive polymer bumps in an atmosphere consisting essentially of ambient room air prior to subsequent bonding.

Claims

1. A circuitry interconnection method comprising:

forming electrically conductive polymer bumps in electrical connection with circuitry supported by a first substrate;

bonding the polymer bumps with a conductive adhesive to circuitry supported by a second substrate, the conductive adhesive being in electrical connection with the circuitry supported by the second substrate; and

prior to said bonding, impinging an effective amount of ultraviolet radiation onto the polymer bumps to enhance adhesion of the bumps with the conductive adhesive and electrical conduction between the circuitry of the first substrate and the circuitry of the second substrate.

2. The method of claim 1 comprising applying a liquid polymer encapsulant over the first substrate and at least one surface of the second substrate and curing said encapsulant into a solid mass;

and prior to said applying, impinging an effective amount of ultraviolet ration onto the one surface to enhance adhesion of the encapsulant to the one surface.

3. The method of claim 1 wherein the first substrate comprises a monolithic integrated circuit chip and the second substrate comprises a polymer sheet.

4. The method of claim 2 wherein the first substrate comprises a monolithic integrated circuit chip and the second substrate comprises a polymer sheet.

5. A circuitry interconnection method comprising:

forming electrically conductive polymer bumps in electrical connection with circuitry supported by a first substrate;

impinging ultraviolet radiation of at least 340 nm wavelength onto the polymer bumps; and

after the impinging, bonding the polymer bumps with a conductive adhesive to circuitry supported by a second substrate, the conductive adhesive being in electrical connection with the circuitry supported by the second substrate.

6. The method of claim 5 comprising applying a liquid polymer encapsulant over the first substrate and at least one surface of the second substrate and curing said encapsulant into a solid mass;

and prior to said applying, impinging an effective amount of ultraviolet ration onto the one surface to enhance adhesion of the encapsulant to the one surface.

7. The method of claim 5 wherein the radiation is impinged to an amount effective to enhance adhesion of the bumps with the conductive adhesive and electrical conduction between the circuitry of the first substrate and the circuitry of the second substrate.

8. The method of claim 5 wherein the ultraviolet radiation wavelength is less than about 450 nm.

9. The method of claim 5 wherein the ultraviolet radiation wavelength is less than about 380 nm.

10. The method of claim 5 wherein the time period of impinging is less than 1 minute.

11. The method of claim 5 wherein the conductive bumps are exposed to a total ultraviolet radiation dose of greater than 50 mJ/cm².

12. The method of claim 5 wherein the impinging occurs in the absence of ozone other than any produced by said ultraviolet radiation.

13. The method of claim 5 wherein the impinging occurs in an atmosphere consisting essentially of ambient room air.

14. A circuitry interconnection method comprising:

forming electrically conductive polymer bumps in electrical connection with circuitry supported by a first substrate;

impinging ultraviolet radiation onto the polymer bumps for a time period less than 1 minute; and

after the impinging, bonding the polymer bumps with a conductive adhesive to circuitry supported by a second substrate, the conductive adhesive being in electrical connection with the circuitry supported by the second substrate.

15. The method of claim 14 comprising applying a liquid polymer encapsulant over the first substrate and at least one surface of the second substrate and curing said encapsulant into a solid mass;

and prior to said applying, impinging an effective amount of ultraviolet radiation onto the one surface to enhance adhesion of the encapsulant to the one surface.

16. The method of claim 14 wherein the radiation is impinged to an amount effective to enhance adhesion of the bumps with the conductive adhesive and electrical conduction between the circuitry of the first substrate and the circuitry of the second substrate.

17. The method of claim 14 wherein the time period is less than 1 second.

18. The method of claim 14 wherein the impinging occurs over multiple discrete time intervals.

19. The method of claim 14 wherein the impinging occurs over at least 3 discrete time intervals.

20. The method of claim 14 wherein the conductive bumps are exposed to a total ultraviolet radiation dose of greater than 50 mJ/cm².

21. The method of claim 14 wherein the impinging occurs in the absence of ozone other than any produced by said ultraviolet radiation.

22. The method of claim 14 wherein the impinging occurs in an atmosphere consisting essentially of ambient room air.

23. A circuitry interconnection method comprising:

forming electrically conductive polymer bumps in electrical connection with circuitry supported by a first substrate;

impinging ultraviolet radiation onto the polymer bumps to provide a total ultraviolet radiation exposure of greater than about 50 mJ/cm²; and

after the impinging, bonding the polymer bumps with a conductive adhesive to circuitry supported by a second substrate, the conductive adhesive being in electrical connection with the circuitry supported by the second substrate.

24. The method of claim 23 comprising applying a liquid polymer encapsulant over the first substrate and at least one surface of the second substrate and curing said encapsulant into a solid mass;

and prior to said applying, impinging an effective amount of ultraviolet radiation onto the one surface to enhance adhesion of the encapsulant to the one surface.

25. The method of claim 23 wherein the radiation is impinged to an amount effective to enhance adhesion of the bumps with the conductive adhesive and electrical conduction between the circuitry of the first substrate and the circuitry of the second substrate.

26. The method of claim 23 wherein the total ultraviolet radiation exposure is less than about 5 J/cm².

27. The method of claim 23 wherein the impinging provides an ultraviolet radiation peak of greater than 50 mW/cm².

28. The method of claim 23 wherein the total ultraviolet radiation exposure is less than about 5 J/cm², and provides an ultraviolet radiation peak of greater than 50 mW/cm².

29. The method of claim 23 wherein the impinging occurs in the absence of ozone other than any produced by said ultraviolet radiation.

30. The method of claim 23 wherein the impinging occurs in an atmosphere consisting essentially of ambient room air.

31. A circuitry interconnection method comprising:

forming electrically conductive polymer bumps in electrical connection with circuitry supported by a first substrate;

impinging ultraviolet radiation onto the polymer bumps in the absence of ozone other than any produced by said ultraviolet radiation; and

after the impinging, bonding the polymer bumps with a conductive adhesive to circuitry supported by a second substrate, the conductive adhesive being in electrical connection with the circuitry supported by the second substrate.

32. The method of claim 31 comprising applying a liquid polymer encapsulant over the first substrate and at least one surface of the second substrate and curing said encapsulant into a solid mass;

and prior to said applying, impinging an effective amount of ultraviolet radiation onto the one surface to enhance adhesion of the encapsulant to the one surface.

33. The method of claim 31 wherein the radiation is impinged to an amount effective to enhance adhesion of the bumps with the conductive adhesive and electrical conduction between the circuitry of the first substrate and the circuitry of the second substrate.

34. A circuitry interconnection method comprising:

forming electrically conductive polymer bumps in electrical connection with circuitry supported by a first substrate;

impinging ultraviolet radiation onto the polymer bumps in an atmosphere consisting essentially of ambient room air; and

after the impinging, bonding the polymer bumps with a conductive adhesive to circuitry supported by a second substrate, the conductive adhesive being in electrical connection with the circuitry supported by the second substrate.

35. The method of claim 34 comprising applying a liquid polymer encapsulant over the first substrate and at least one surface of the second substrate and curing said encapsulant into a solid mass;

and prior to said applying, impinging an effective amount of ultraviolet radiation onto the one surface to enhance adhesion of the encapsulant to the one surface.

36. The method of claim 34 wherein the radiation is impinged to an amount effective to enhance adhesion of the bumps with the conductive adhesive and electrical conduction between the circuitry of the first substrate and the circuitry of the second substrate.

37. A circuitry interconnection method comprising:

forming electrically conductive polymer bumps in electrical connection with circuitry supported by a first substrate;

impinging ultraviolet radiation of at least 340 nm wavelength onto the polymer bumps to provide a total ultraviolet radiation exposure of at least about 50 mJ/cm² over a time period of no greater than 1 minute in an atmosphere consisting essentially of ambient room air; and

after the impinging, bonding the polymer bumps with a conductive adhesive to circuitry supported by a second substrate, the conductive adhesive being in electrical connection with the circuitry supported by the second substrate.

38. The method of claim 37 wherein the ultraviolet radiation wavelength is less than about 450 nm.

39. The method of claim 37 wherein the ultraviolet radiation wavelength is less than about 380 nm.

40. The method of claim 37 wherein the time period is less than 1 second.

41. The method of claim 37 wherein the impinging occurs over multiple discrete time intervals.

42. The method of claim 37 wherein the impinging occurs over at least 3 discrete time intervals.

43. The method of claim 37 wherein the total ultraviolet radiation exposure is less than about 5 J/cm².

44. The method of claim 37 wherein the impinging provides an ultraviolet radiation peak of greater than 50 mW/cm².

45. The method of claim 37 wherein the total ultraviolet radiation exposure is less than about 5 J/cm², and provides an ultraviolet radiation peak of greater than 50 mW/cm².

46. A circuitry interconnection method comprising:

forming electrically conductive polymer bumps in electrical connection with circuitry supported by a first substrate;

providing the first substrate, bumps out, onto a movable belt of an ultraviolet light radiation system;

operating an ultraviolet lamp of the system onto a region of the belt within a range of about 50 Watts per linear inch in a direction of belt travel to about 600 Watts per linear inch in the direction;

moving the belt to pass the bumps of the first substrate through the region with the ultraviolet lamp operating; and

after passing the bumps through the region, bonding the polymer bumps with a conductive adhesive to circuitry supported by a second substrate, the conductive adhesive being in electrical connection with the circuitry supported by the second substrate.

47. The method of claim 46 comprising applying a liquid polymer encapsulant over the first substrate and at least one surface of the second substrate and curing said encapsulant into a solid mass;

and prior to said applying, impinging an effective amount of ultraviolet radiation onto the one surface to enhance adhesion of the encapsulant to the one surface.

48. The method of claim 46 wherein the radiation is impinged to an amount effective to enhance adhesion of the bumps with the conductive adhesive and electrical conduction between the circuitry of the first substrate and the circuitry of the second substrate.

49. The method of claim 46 wherein the time period of impinging is less than 1 minute.

50. The method of claim 46 wherein the conductive bumps are exposed to a total ultraviolet radiation dose of greater than 50 mJ/cm².

51. The method of claim 46 wherein the impinging occurs in the absence of ozone other than any produced by said ultraviolet radiation.

52. The method of claim 46 wherein the impinging occurs in an atmosphere consisting essentially of ambient room air.

53. The method of claim 46 wherein wavelength of the ultraviolet radiation is at least 340 nm.