Multilayer flexible wiring boards

• US 6,653,736 B2
• Filed: 12/20/2002
• Issued: 11/25/2003
• Est. Priority Date: 11/10/1999
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Chemicals Corp. (Dexerials Corporation)
• Inventors: Kishimoto, Soichiro, Hishinuma, Hiroyuki
• Primary Examiner(s): POTTER, ROY KARL
• Application Number:
  US10/323,915
• Publication Number:
  US 20030089984A1
• Time in Patent Office: 340 Days
• Field of Search: 257/738, 257/758, 257/762, 257/768, 257/769, 257/774
• US Class Current: 257/758
• CPC Class Codes: H01L 21/4857 Multilayer substrates multilayer metallisation on monolayer substrate H01L21/4846
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 23/49833 the chip support structure consisting of a plurality of insulating substrates
• CPC Class Codes: H01L 23/4985 Flexible insulating substrates H01L23/49572 and H01L23/49855 take precedence
• CPC Class Codes: H01L 2924/01046 Palladium [Pd]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• 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 2201/0129 Thermoplastic polymer, e.g. auto-adhesive layer; Shaping of thermoplastic polymer
• CPC Class Codes: H05K 2201/0195 Dielectric or adhesive layers comprising a plurality of layers, e.g. in a multilayer structure
• CPC Class Codes: H05K 2201/0367 Metallic bump or raised conductor not used as solder bump
• CPC Class Codes: H05K 2201/0394 Conductor crossing over a hole in the substrate or a gap between two separate substrate parts
• CPC Class Codes: H05K 2203/0285 Using ultrasound, e.g. for cleaning, soldering or wet treatment
• CPC Class Codes: H05K 2203/1189 Pressing leads, bumps or a die through an insulating layer
• CPC Class Codes: H05K 3/244 Finish plating of conductors, especially of copper conductors, e.g. for pads or lands selective plating methods H05K3/243; finish plating of conductors made by printing techniques H05K3/246; solder as finish H05K3/3457, e.g. by plating H05K3/3473
• 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 3/4617 characterized by laminating only or mainly similar single-sided circuit boards
• CPC Class Codes: H05K 3/4635 laminating flexible circuit boards using additional insulating adhesive materials between the boards

Abstract

A multilayer flexible wiring board, suited for mounting semiconductor elements. The flexible wiring board is fabricated in the following manner. A flexible wiring board piece having a metal wiring, in which a metal coating is exposed on at least a part of surface of the metal wiring, is adhered to another flexible wiring board piece having a metal projection on which a metal coating is formed. One of or both of the metal coatings on the metal wiring and the metal projection is composed of a soft metal coating a surface of which has a Vickers'"'"' hardness of 80 kgf/mm² or lower. The metal coating of the metal wiring contacts with the metal coating of said metal projection and ultrasonic wave is applied thereto to connect the metal wiring with the metal projection.

Claims

1. A multilayer flexible wiring board comprising;

at least two layers of metal wirings are laminated while interposing at least an insulating layer therebetween,

metal projections provided on one of said metal wirings are connected with the other metal wiring by the application of ultrasonic wave, wherein soft metal coating having a Vickers'"'"' hardness of 80 kgf/mm² or lower is formed on at least one of surfaces of said metal projections and said metal wiring to be connect with said metal projections.

2. The flexible wiring board according to claim 1, wherein said soft metal coating is composed of one or more metal coating selected from the group consisting of a gold coating including gold as a main component, a platinum coating including platinum as a main component, a silver coating including silver as a main component, and a palladium coating including palladium as a main component.

7. An electric device comprising the multilayer flexible wiring board according to claim 1 and an electric part connected with said flexible wiring board by soldering.

8. An electric device comprising the multilayer flexible wiring board according to claim 2 and an electric part connected with said flexible wiring board by soldering.

3. A multilayer flexible wiring board comprising;

at least two layers of metal wirings are laminated while interposing at least an insulating layer therebetween,

metal projections provided on one of said metal wirings are connected with the other metal wiring by the application of ultrasonic wave, wherein soft metal coating having a Vickers'"'"' hardness of 80 kgf/mm² or lower is formed on one of surfaces of said metal projections and the metal wiring connected with said metal projections, and hard metal coating having a Vickers'"'"' hardness of 120 kgf/mm² or higher and soft metal coating having a Vickers'"'"' hardness of 80 kgf/mm² or lower are layered on the other of the surfaces of said metal projections and the metal wiring connected with said metal projections, and wherein the soft metal coating formed on the surface of said metal projections are connected with the soft metal coating formed on said metal wiring by the application of ultrasonic wave.

4. The multilayer flexible wiring board according to claim 3, wherein said hard metal coating is composed of nickel coating including nickel as a main component.

5. The multilayer flexible wiring board according to claim 3, wherein one of or both of said soft metal coating formed on the surfaces of said metal projections and formed on the metal wiring is composed of one or more metal coating selected from the group consisting of a gold coating including gold as a main component, a platinum coating including platinum as a main component, a silver coating including silver as a main component, and a palladium coating including palladium as a main component.

6. The multilayer flexible wiring board according to claim 4, wherein one of or both of said soft metal coating formed on the surfaces of said metal projections and formed on the said metal wiring is composed of one or more metal coating selected from the group consisting of a gold coating including gold as a main component, a platinum coating including platinum as a main component, a silver coating including silver as a main component, and a palladium coating including palladium as a main component.

9. An electric device comprising the multilayer flexible wiring board according to claim 3 and an electric part connected with said flexible wiring board by soldering.

10. An electric device comprising the multilayer flexible wiring board according to claim 4 and an electric part connected with said flexible wiring board by soldering.

11. An electric device comprising the multilayer flexible wiring board according to claim 5 and an electric part connected with said flexible wiring board by soldering.

12. An electric device comprising the multilayer flexible wiring board according to claim 6 and an electric part connected with said flexible wiring board by soldering.