Method for making a flexible circuit interposer having high-aspect ratio conductors

• US 6,580,031 B2
• Filed: 11/30/2000
• Issued: 06/17/2003
• Est. Priority Date: 03/14/2000
• Status: Expired due to Fees

• Current Assignee: Amerasia International Technology, Inc.
• Original Assignee: Amerasia International Technology, Inc.
• Inventors: Chung, Kevin Kwong-Tai
• Primary Examiner(s): Reichard, Dean A.
• Assistant Examiner(s): OLIVA, CARMELO B
• Application Number:
  US09/727,307
• Publication Number:
  US 20020046873A1
• Time in Patent Office: 929 Days
• Field of Search: 174/52.2, 174/52.3, 174/52.4, 174/255, 174/259, 174/260, 361/749, 361/750, 298/29, 298/33, 298/35, 298/41, 298/42, 298/48, 298/44, 298/46
• US Class Current: 174/525
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/16237 the bump connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48 of an individual wire connector
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• CPC Class Codes: H01L 2225/0651 Wire or wire-like electrical connections from device to substrate
• CPC Class Codes: H01L 2225/06517 Bump or bump-like direct electrical connections from device to substrate
• CPC Class Codes: H01L 2225/0652 Bump or bump-like direct electrical connections from substrate to substrate
• CPC Class Codes: H01L 2225/06527 Special adaptation of electrical connections, e.g. rewiring, engineering changes, pressure contacts, layout
• CPC Class Codes: H01L 2225/06541 Conductive via connections through the device, e.g. vertical interconnects, through silicon via [TSV]
• CPC Class Codes: H01L 2225/06572 Auxiliary carrier between devices, the carrier having an electrical connection structure
• CPC Class Codes: H01L 2225/06579 TAB carriers; beam leads
• CPC Class Codes: H01L 2225/06582 Housing for the assembly, e.g. chip scale package [CSP]
• CPC Class Codes: H01L 2225/06586 Housing with external bump or bump-like connectors
• CPC Class Codes: H01L 23/055 the leads having a passage through the base H01L23/057 takes precedence
• CPC Class Codes: H01L 23/49838 Geometry or layout
• CPC Class Codes: H01L 23/4985 : Flexible insulating substrates H01L23/49572 and H01L23/49855 take precedence
• CPC Class Codes: H01L 23/5387 : Flexible insulating substrates H01L23/5388 takes precedence
• CPC Class Codes: H01L 25/0657 : Stacked arrangements of devices
• 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 2924/00011 : Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01021 : Scandium [Sc]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/15174 : in different layers of the multilayer substrate
• CPC Class Codes: H01L 2924/207 : Diameter ranges
• CPC Class Codes: H01Q 1/22 : by structural association with other equipment or articles
• CPC Class Codes: H01Q 1/2208 : associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 1/36 : Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 1/38 : formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 23/00 : Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 7/00 : Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 7/005 : with variable reactance for tuning the antenna
• CPC Class Codes: H01R 12/52 : connecting to other rigid printed circuits or like structures
• CPC Class Codes: H01R 43/007 : for elastomeric connecting elements
• CPC Class Codes: H05K 2201/09481 : Via in pad; Pad over filled via
• CPC Class Codes: H05K 3/4038 : Through-connections; Vertical interconnect access [VIA] connections H05K3/403, H05K3/42 take precedence
• CPC Class Codes: Y10T 29/49124 : On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/49135 : and shaping, e.g., cutting or bending, etc.
• CPC Class Codes: Y10T 29/49147 : Assembling terminal to base

Abstract

A low-modulus-of-elasticity flexible adhesive interposer substrate has high aspect ratio via conductors to which an electronic device, such as a semiconductor chip or die or other component, is attached, e.g., for a high density electronic package. A method for making the flexible adhesive interposer substrate includes etching a sheet of metal to form the high aspect ratio via conductors which are held in position by a sheet or layer of a molecularly flexible adhesive. The via conductors may be built up to even greater aspect ratio. Such flexible interposer may include high aspect ratio via conductors for a plurality of similar or different electronic devices.

Claims

1. A method for making an interposer comprising:

providing a sheet of metal;

removing part of the sheet of metal to leave a plurality of columnar conductors having distal ends projecting from a remaining web of the sheet of metal;

applying a layer of dielectric adhesive on the remaining web and surrounding the columnar conductors except for the distal ends thereof;

removing at least part of the remaining web to electrically isolate ones of the columnar conductors from others of the columnar conductors.

2. The method of claim 1 wherein said removing part of the sheet of metal comprises removing a first part of the sheet of metal to leave a plurality of first columnar conductors having distal ends projecting from a first surface of the remaining web, and wherein said removing at least part of the remaining web comprises removing a second part of the sheet of metal to leave a plurality of second conductors ones of which are electrically connected to corresponding ones of the first columnar conductors.

3. The method of claim 1 wherein said removing part of the sheet of metal comprises removing a first part of the sheet of metal to leave a plurality of first columnar conductors having distal ends projecting from a first surface of the remaining web and removing a second part of the sheet of metal to leave a plurality of second columnar conductors having distal ends projecting from a second surface of the remaining web.

4. The method of claim 1 further comprising applying a layer of a conductive material on the distal ends of the columnar conductors.

5. The method of claim 4 wherein said applying a layer of a conductive material includes applying a layer of at least one of a metal, a precious metal, a noble metal, a combination thereof, an alloy thereof, solder, and an electrically conductive adhesive.

6. The method of claim 4 wherein said applying a layer of a conductive material includes applying a layer of at least one of copper, aluminum, brass, tin, solder, silver, gold, palladium, nickel, nickel/gold, nickel/palladium, a combination thereof and an alloy thereof.

7. The method of claim 1 wherein said applying a layer of dielectric adhesive includes applying a layer of a flexible dielectric adhesive.

8. The method of claim 7 wherein said applying a layer of flexible dielectric adhesive includes applying a dielectric adhesive that has a modulus of elasticity of less than about 35,000 kg/cm² (about 500,000 psi) and that withstands an elongation of at least 30% in length without failure.

9. The method of claim 7 wherein said applying a layer of flexible dielectric adhesive includes applying a dielectric adhesive that has a modulus of elasticity of less than about 7,000 kg/cm² (about 100,000 psi) and that withstands an elongation of at least 30% in length without failure.

10. The method of claim 1 further comprising:

providing an electronic device having contacts thereon; and

connecting the contacts of the electronic device to respective first ends of ones of the columnar conductors.

11. The method of claim 10 wherein said connecting the contacts includes:

applying one of solder and electrically-conductive adhesive to one of the contacts of the electronic device and the first ends of ones of the columnar conductors; and

joining the contacts of the electronic device and corresponding ones of the first ends of the ones of the columnar conductors with the one of the solder and the electrically-conductive adhesive.

12. The method of claim 10 further comprising:

providing an electronic substrate having contact sites thereon; and

connecting the contact sites of the electronic substrate to respective second ends of ones of the columnar conductors.

13. The method of claim 12 wherein said connecting the contact sites includes:

applying one of solder and electrically-conductive adhesive to one of the contact sites of the electronic substrate and the second ends of ones of the columnar conductors; and

joining the contact sites of the electronic substrate and corresponding ones of the second ends of the ones of the columnar conductors with the one of the solder and the electrically-conductive adhesive.

14. The method of claim 10 wherein said providing an electronic device includes:

providing an electronic component having contacts thereon, and/or

providing a semiconductor wafer including a plurality of electronic circuits thereon each having a pattern of contacts.

15. The method of claim 14 further comprising separating the semiconductor wafer into individual semiconductor die each including at least one of the electronic circuits and having the corresponding ones of the columnar conductors connected thereto.

16. The method of claim 1 further comprising applying on the layer of dielectric adhesive applied on the remaining web a film of a non-intrinsically flexible dielectric material.

17. The method of claim 16 wherein said applying a film of a non-intrinsically flexible dielectric material includes applying a film of one of a polyimide, a low-CTE polyimide and a liquid crystal polymer.

18. The method of claim 1 wherein the columnar conductors include at least a section that is solid metal and have an aspect ratio of at least 1.5.

19. A method for making a uniaxially conductive sheet comprising:

providing a sheet of metal;

removing part of the sheet of metal to leave a plurality of columnar conductors having distal ends projecting from a remaining web of the sheet of metal, wherein the columnar conductors are substantially uniformly and closely spaced;

applying a layer of dielectric adhesive on the remaining web and surrounding the columnar conductors except for the distal ends thereof;

removing at least part of the remaining web to electrically isolate ones of the columnar conductors from others of the columnar conductors.

20. The method of claim 19 wherein said removing part of the sheet of metal comprises removing a first part of the sheet of metal to leave a plurality of first columnar conductors having distal ends projecting from a first surface of the remaining web, and wherein said removing at least part of the remaining web comprises removing a second part of the sheet of metal to leave a plurality of second conductors ones of which are electrically connected to corresponding ones of the first columnar conductors.

21. The method of claim 19 wherein said removing part of the sheet of metal comprises removing a first part of the sheet of metal to leave a plurality of first columnar conductors having distal ends projecting from a first surface of the remaining web and removing a second part of the sheet of metal to leave a plurality of second columnar conductors having distal ends projecting from a second surface of the remaining web.

22. The method of claim 19 further comprising applying a layer of a conductive material on the distal ends of the columnar conductors.

23. The method of claim 22 wherein said applying a layer of a conductive material includes applying a layer of at least one of a metal, a precious metal, a noble metal, a combination thereof, an alloy thereof, solder, and an electrically conductive adhesive.

24. The method of claim 22 wherein said applying a layer of a conductive material includes applying a layer of at least one of copper, aluminum, brass, tin, solder, silver, gold, palladium, nickel, nickel/gold, nickel/palladium, a combination thereof and an alloy thereof.

25. The method of claim 19 wherein said applying a layer of dielectric adhesive includes applying a layer of a flexible dielectric adhesive.

26. The method of claim 25 wherein said applying a layer of flexible dielectric adhesive includes applying a dielectric adhesive that has a modulus of elasticity of less than about 35,000 kg/cm² (about 500,000 psi) and that withstands an elongation of at least 30% in length without failure.

27. The method of claim 25 wherein said applying a layer of flexible dielectric adhesive includes applying a dielectric adhesive that has a modulus of elasticity of less than about 7,000 kg/cm² (about 100,000 psi) and that withstands an elongation of at least 30% in length without failure.

28. The method of claim 19 wherein the columnar conductors include at least a section that is solid metal and have an aspect ratio of at least 1.5.

29. The method of claim 19 further comprising:

providing at least one of an electronic device having contacts thereon, an electronic component having contacts thereon, and/or a semiconductor wafer including a plurality of electronic circuits thereon each having contacts thereon; and

connecting the contacts to respective first ends of the columnar conductors.

30. The method of claim 29 further comprising separating the semiconductor wafer into individual semiconductor die each including at least one of the electronic circuits and having the corresponding ones of the columnar conductors connected thereto.

31. A method for making an electronic device comprising:

providing a sheet of metal;

providing an electronic component having contacts thereon;

removing part of the sheet of metal to leave a plurality of columnar conductors having distal ends projecting from a remaining web of the sheet of metal;

applying a layer of dielectric adhesive on the remaining web and surrounding the columnar conductors except for the distal ends thereof;

removing at least part of the remaining web to electrically isolate ones of the columnar conductors from others of the columnar conductors; and

connecting the contacts of the electronic component to respective first ends of ones of the columnar conductors.

32. The method of claim 31 wherein said connecting the contacts includes:

applying one of solder and electrically-conductive adhesive to one of the contacts of the electronic component and the first ends of ones of the columnar conductors; and

joining the contacts of the electronic component and corresponding ones of the first ends of the ones of the columnar conductors with the one of the solder and the electrically-conductive adhesive.

33. The method of claim 32 wherein said applying one of solder and electrically-conductive adhesive includes applying a pressure-sensitive electrically-conductive thermosetting adhesive that cures at a temperature of less than about 60°

C.

34. The method of claim 33 wherein the pressure-sensitive electrically-conductive thermosetting adhesive has an immediate bond strength of at least about 100 psi and has a cured bond strength of at least about 1000 psi.

35. The method of claim 31 further comprising:

providing an electronic substrate having contact sites thereon; and

connecting the contact sites of the electronic substrate to respective second ends of ones of the columnar conductors.

36. The method of claim 35 wherein said connecting the contact sites includes:

applying one of solder and electrically-conductive adhesive to one of the contact sites of the electronic substrate and the second ends of ones of the columnar conductors; and

joining the contact sites of the electronic substrate and corresponding ones of the second ends of the ones of the columnar conductors with the one of the solder and the electrically-conductive adhesive.

37. The method of claim 31 wherein the columnar conductors include at least a section that is solid metal and have an aspect ratio of at least 1.5.

38. The method of claim 31 wherein said providing an electronic component having contacts thereon includes providing at least one of an electronic device having contacts thereon, and/or a semiconductor wafer including a plurality of electronic circuits thereon each having contacts thereon.

39. The method of claim 38 further comprising separating the semiconductor wafer into individual semiconductor die each including at least one of the electronic circuits and having the corresponding ones of the columnar conductors connected thereto.

40. A method for making an electronic device comprising:

providing a sheet of metal;

providing a semiconductor wafer including a plurality of electronic circuits thereon each having a pattern of contacts;

removing part of the sheet of metal to leave a plurality of columnar conductors having distal ends projecting from a remaining web of the sheet of metal, the plurality of columnar conductors being in patterns corresponding to the patterns of contacts of the semiconductor wafer;

applying a layer of dielectric adhesive on the remaining web and surrounding the columnar conductors except for the distal ends thereof;

removing at least part of the remaining web to electrically isolate ones of the columnar conductors from others of the columnar conductors;

connecting the contacts of the semiconductor wafer to respective first ends of ones of the columnar conductors of the interposer, whereby the columnar conductors are connected to the semiconductor wafer; and

separating the semiconductor wafer and interposer connected thereto into individual semiconductor die each including at least one of the electronic circuits and having the corresponding ones of the columnar conductors connected thereto.

41. The method of claim 40 wherein said connecting the contacts includes:

applying one of solder and electrically-conductive adhesive to one of the contacts of the semiconductor wafer and first ends of ones of the columnar conductors; and

joining the contacts of the semiconductor wafer and corresponding ones of the first ends of the ones of the columnar conductors with the one of the solder and the electrically-conductive adhesive.

42. The method of claim 41 wherein said applying one of solder and electrically-conductive adhesive includes applying a pressure-sensitive electrically-conductive thermosetting adhesive that cures at a temperature of less than about 60°

C.

43. The method of claim 42 wherein the pressure-sensitive electrically-conductive thermosetting adhesive has an immediate bond strength of at least about 100 psi and has a cured bond strength of at least about 1000 psi.

44. The method of claim 40 further comprising:

providing an electronic substrate having contact sites thereon; and

connecting the contact sites of the electronic substrate to respective second ends of the columnar conductors connected to the semiconductor die.

45. The method of claim 44 wherein said connecting the contact sites includes:

applying one of solder and electrically-conductive adhesive to one of the contact sites of the electronic substrate and the second ends of the columnar conductors; and

joining the contact sites of the electronic substrate and corresponding second ends of the columnar conductors with the one of the solder and the electrically-conductive adhesive.

46. The method of claim 40 wherein the columnar conductors include at least a section that is solid metal and have an aspect ratio of at least 1.5.

47. A method for making an interposer comprising:

providing a sheet of metal;

bonding a plurality of wires to the sheet of metal to provide a plurality of columnar conductors having first ends at the sheet of metal and distal ends projecting from the sheet of metal;

applying a layer of dielectric adhesive on the sheet of metal and surrounding the columnar conductors except for the distal ends thereof;

removing at least part of the sheet of metal to electrically isolate ones of the columnar conductors from others of the columnar conductors.

48. The method of claim 47 further comprising advancing the sheet of metal in the work space of a wire bonder for said bonding of a plurality of wires to the sheet of metal.

49. The method of claim 47 wherein said removing at least part of the sheet of metal comprises one of removing a first part of the sheet of metal to leave a plurality of first columnar conductors having distal ends projecting from the first ends of the columnar conductors, and removing the sheet of metal to expose the first ends of the columnar conductors.

50. The method of claim 47 wherein the columnar conductors include at least a section that is solid metal and have an aspect ratio of at least 1.5.

51. The method of claim 47 further comprising:

providing at least one of an electronic device having contacts thereon, an electronic component having contacts thereon, and/or a semiconductor wafer including a plurality of electronic circuits thereon each having contacts thereon; and

connecting the contacts to respective first ends of the columnar conductors.

52. The method of claim 51 further comprising separating the semiconductor wafer into individual semiconductor die each including at least one of the electronic circuits and having the corresponding ones of the columnar conductors connected thereto.