Anisotropic conductive film for microconnections

• US 5,879,530 A
• Filed: 05/29/1997
• Issued: 03/09/1999
• Est. Priority Date: 10/28/1994
• Status: Expired due to Fees

• Current Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Original Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Inventors: Caillat, Patrice
• Primary Examiner(s): Gorgos, Kathryn
• Assistant Examiner(s): Wong, Edna
• Application Number:
  US08/865,129
• Time in Patent Office: 649 Days
• Field of Search: 205/76, 205/78, 205/122, 205/183, 205/191, 205/224, 427/259, 427/264, 427/270, 427/272
• US Class Current: 205/122
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 2221/68345 used as a support during the manufacture of self supporting substrates
• CPC Class Codes: H01L 2224/13111 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 23/4922 having a heterogeneous or anisotropic structure
• CPC Class Codes: H01L 23/49827 Via connections through the substrates, e.g. pins going through the substrate, coaxial cables H01L23/49822, H01L23/49833, H01L23/4985, H01L23/49861 take precedence
• 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 2924/01057 Lanthanum [La]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H05K 2201/09563 Metal filled via
• CPC Class Codes: H05K 2201/09945 Universal aspects, e.g. universal inner layers or via grid, or anisotropic interposer
• CPC Class Codes: H05K 2201/10378 Interposers
• CPC Class Codes: H05K 2201/10977 Encapsulated connections
• CPC Class Codes: H05K 2201/10992 Using different connection materials, e.g. different solders, for the same connection
• CPC Class Codes: H05K 2203/0733 Method for plating stud vias, i.e. massive vias formed by plating the bottom of a hole without plating on the walls
• CPC Class Codes: H05K 3/303 Surface mounted components, e.g. affixing before soldering, aligning means, spacing means H05K3/32 takes precedence
• CPC Class Codes: H05K 3/3436 having an array of bottom contacts, e.g. pad grid array or ball grid array components
• CPC Class Codes: H05K 3/3463 Solder compositions in relation to features of the printed circuit board or the mounting process
• CPC Class Codes: H05K 3/4038 Through-connections; Vertical interconnect access [VIA] connections H05K3/403, H05K3/42 take precedence
• CPC Class Codes: H05K 3/423 : characterised by electroplating method
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10S 428/901 : Printed circuit
• CPC Class Codes: Y10T 428/24917 : including metal layer
• CPC Class Codes: Y10T 428/2804 : Next to metal
• CPC Class Codes: Y10T 428/2848 : Three or more layers

Abstract

This self-supported, anisotropic conductive film has a partly annealed polymer layer (46) containing through holes, nail-shaped conductive elements (51) filling the through holes, having a central portion and ends, and the central portion of the nails is made from a hard material (52) and each end respectively of a first and a second meltable materials (44, 54).

Claims

1. Process for the production of an anisotropic conductive film, comprising the steps of:

depositing a layer of a first meltable material on a substrate,

depositing a polymer layer on the layer of first meltable material,

annealing said polymer layer,

forming through holes in the polymer layer,

depositing a hard conductive material in the holes wherein the hard conductive material has a melting point that is higher than that of the first meltable material,

depositing a second meltable material on the hard material, and

heating to a temperature T equal to or above the melting point of the first meltable material, and in this way debonding the anisotropic conductive film comprising the polymer layer which contains the hard conductive material in the holes from the substrate.

2. Process according to claim 1, wherein on the substrate, prior to the deposition of the first meltable material layer, is deposited an attachment layer for the first meltable material.

3. Process according to claim 2, wherein the attachment layer is TiNiAu.

4. Process according to claim 3, wherein the first and second meltable materials are identical.

5. Process according to claim 3, wherein the hard material is selected from the group consisting of Cu, Ni, and 5% Sn--95% Pb.

6. Process according to claim 3, wherein the first and second meltable materials is 60% Sn--40% Pb.

7. Process according to claim 3, wherein the hard material and the second meltable material are formed by electrolysis using the first meltable material as an electrode for electrolysis.

8. Process according to claim 3, wherein the annealing of the polymer layer is partial.

9. Process according to claim 1, wherein the first and second meltable materials are identical.

10. Process according to claim 1, wherein the hard material is selected from the group consisting of Cu, Ni, and 5% Sn--95% Pb.

11. Process according to claim 1, wherein the first and second meltable materials are 60% Sn--40% Pb.

12. Process according to claim 1, wherein the hard material and the second meltable material are formed by electrolysis using the first meltable material as an electrode for electrolysis.

13. Process according to claim 1, wherein the annealing of the polymer layer is partial.

14. The process according to claim 1 wherein the anisotropic conductive film produced comprises a polymer layer that has at least one of the first meltable material or the second meltable material projecting from the polymer layer.

15. The process according to claim 1 wherein the anisotropic conductive film produced comprises a polymer layer that has both the first meltable material and the second meltable material projecting from the polymer layer.