Substrate coated with a conductive layer and manufacturing method thereof

• US 6,651,871 B2
• Filed: 11/18/2002
• Issued: 11/25/2003
• Est. Priority Date: 11/17/1999
• Status: Expired due to Fees

• Current Assignee: Ebara Corporation
• Original Assignee: Ebara Corporation
• Inventors: Ogure, Naoaki
• Primary Examiner(s): Elve, M. Alexandra
• Assistant Examiner(s): DUNN, COLLEEN P
• Application Number:
  US10/298,291
• Publication Number:
  US 20030059541A1
• Time in Patent Office: 372 Days
• Field of Search: 228/123.1, 228/120, 228/245, 228/246, 228/248.1, 148/512, 148/516, 148/537, 148/678, 298/25, 298/29, 295/272, 427/96, 427/123, 427/124, 427/125, 427/191, 427/217, 427/372.2, 427/375, 427/376.6, 427/376.7, 427/383.1, 427/383.2
• US Class Current: 228/248.1
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• 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 2201/0108 Transparent
• CPC Class Codes: H05K 2201/0257 Nanoparticles
• CPC Class Codes: H05K 3/102 by bonding of conductive powder, i.e. metallic powder H05K3/12 takes precedence
• CPC Class Codes: H05K 3/108 by semi-additive methods; masks therefor characterised by metallic etch mask H05K3/062; electroplating methods or apparatus H05K3/241
• CPC Class Codes: H05K 3/38 Improvement of the adhesion between the insulating substrate and the metal
• CPC Class Codes: Y10T 428/12014 having metal particles
• CPC Class Codes: Y10T 428/12028 Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]

Abstract

A substrate is coated with a conductive layer, which comprises a conductive layer of bonded ultrafine metal particles formed on the top surface thereof. The ultrafine metal particles have a diameter of 1-20 nm, and the substrate is of a flexible high polymer material. Since the conductive layer is formed by bonded layer of the ultrafine metal particles, an extremely thin layer having high conductivity can be formed. This structure enables the formation of a flexible printed circuit board with high-density interconnects or a transparent conductive film provided with both transparency and conductivity. Conventional vacuum equipments and complicated processes are not necessary for forming the conductive layer on the substrate.

Claims

1. A method of manufacturing a substrate coated with a conductive layer, comprising:

preparing a substrate;

preparing ultrafine metal particles said ultrafine metal particles comprising a core formed essentially of a metal component and a coating formed of an organic compound, wherein the core is coated with the coating;

dispersing the ultrafine metal particles in a solvent for preparing a solution of ultrafine metal particles, and the coating prevents agglomeration of the cores;

introducing the ultrafine particle solution onto a surface of the substrate; and

heating the ultrafine metal particles to decompose the coating and bonding the cores together to form the conductive layer.

2. The method of claim 1, wherein the ultrafine metal particles are ultrafine silver particles obtained by thermal decomposition of an organic complex or metallic salt comprising silver.

3. The method of claim 1, wherein the ultrafine metal particles have a diameter of 1-20 nm.

4. The method of claim 1, wherein the substrate is made of a flexible material.

5. The method of claim 1, wherein the substrate is made of a transparent material.

6. The method of claim 4, wherein the flexible material comprises a flexible high polymer material.

7. The method of claim 5, wherein a size and a compound ratio of the complex ultrafine metal particles are adjusted so that the thickness of the conductive layers is 3-15 nm after the heating process.