Wired circuit board and producing method thereof

• US 8,692,126 B2
• Filed: 08/16/2010
• Issued: 04/08/2014
• Est. Priority Date: 08/26/2009
• Status: Active Grant

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Ishii, Jun, Iguchi, Hirotoshi
• Primary Examiner(s): SMITH, COURTNEY L
• Application Number:
  US12/805,710
• Publication Number:
  US 20110048785A1
• Time in Patent Office: 1,331 Days
• Field of Search: 174/250, 174258-268, 174/350, 174/520, 174/524, 174/527, 174/528, 174/531, 174/546, 174/549, 174/552
• US Class Current: 174/255
• CPC Class Codes: G11B 5/484 Integrated arm assemblies, e.g. formed by material deposition or by etching from single piece of metal or by lamination of materials forming a single arm/suspension/head unit
• CPC Class Codes: H05K 1/056 the metal substrate being covered by an organic insulating layer
• CPC Class Codes: H05K 1/189 characterised by the use of a flexible or folded printed circuit H05K3/326 takes precedence
• CPC Class Codes: H05K 2201/09063 Holes or slots in insulating substrate not used for electrical connections
• CPC Class Codes: H05K 2201/0969 Apertured conductors
• CPC Class Codes: H05K 2201/09781 Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components
• CPC Class Codes: H05K 2201/09827 Tapered, e.g. tapered hole, via or groove bevelled, chamferred or tapered edge H05K2201/09154
• CPC Class Codes: H05K 2201/09845 Stepped hole, via, edge, bump or conductor
• CPC Class Codes: H05K 2201/09854 Hole or via having special cross-section, e.g. elliptical
• CPC Class Codes: H05K 2203/0323 Working metal substrate or core, e.g. by etching, deforming
• CPC Class Codes: H05K 2203/0369 Etching selective parts of a metal substrate through part of its thickness, e.g. using etch resist
• CPC Class Codes: H05K 2203/167 Using mechanical means for positioning, alignment or registration, e.g. using rod-in-hole alignment
• 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: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/49126 Assembling bases

Abstract

A wired circuit board includes a metal supporting layer, an insulating layer formed on the metal supporting layer, and a conductive layer formed on the insulating layer. In the metal supporting layer, a reference hole for positioning is formed, and a stepped portion is formed so as to surround the reference hole.

Claims

1. A wired circuit board, comprising:

a metal supporting layer;

an insulating layer formed on the metal supporting layer; and

a conductive layer formed on the insulating layer,

wherein a reference hole for positioning is formed in the metal supporting layer, and a stepped portion is formed so as to surround on all sides the reference hole; and

wherein the stepped portion is formed in at least one of;

a) the same layer as the insulating layer, b) the same layer as the conductive layer, or c) directly in the metal supporting layer.

2. The wired circuit board according to claim 1, wherein a distance between the stepped portion and the reference hole is not more than 100 μ

m.

3. The wired circuit board according to claim 1, wherein the stepped portion has a thickness of not less than 5 μ

m.

4. The wired circuit board according to claim 1, wherein the insulating layer is formed of polyimide.

5. The wired circuit board according to claim 1, wherein the conductive layer is formed of copper.

6. The wired circuit board according to claim 1, which is used as a suspension board with circuit.

10. The wired circuit board according to claim 1, wherein the reference hole for positioning is circular, and

wherein the stepped portion is circular and is formed so as to concentrically surround the circular reference hole.

11. The wired circuit board according to claim 10, wherein the circular stepped portion comprises a first stepped portion having a generally annular shape in plan view concentrically surrounding the circular reference hole.

7. A producing method of a wired circuit board, comprising:

the step of forming a metal supporting layer, forming an insulating layer on the metal supporting layer, and forming a conductive layer on the insulating layer;

the step of forming a stepped portion, which is formed in at least one of;

a) the same layer as the insulating layer, b) the same layer as the conductive layer, or c) directly in the metal supporting layer, such that a to-be-removed region for boring a reference hole used for positioning is surrounded on all sides by the stepped portion; and

a reference hole forming step of etching the to-be-removed region of the metal supporting layer to form the reference hole, wherein

the reference hole forming step includes the steps of;

forming an etching resist so as to cover the stepped portion therewith on one side of the metal supporting layer in a thickness direction and expose the to-be-removed region on the other side of the metal supporting layer in the thickness direction;

removing the to-be-removed region exposed from the etching resist by etching; and

removing the etching resist.

8. The producing method of a wired circuit board according to claim 7, wherein the reference hole for positioning is circular, and

wherein the stepped portion is circular and is formed so as to concentrically surround the circular reference hole.

9. The producing method of a wired circuit board according to claim 8, wherein the circular stepped portion comprises a first stepped portion having a generally annular shape in plan view concentrically surrounding the circular reference hole.

12. A wired circuit board, comprising:

a metal supporting layer;

an insulating layer formed on the metal supporting layer; and

a conductive layer formed on the insulating layer,

wherein a reference hole for positioning is formed in the metal supporting layer, and a stepped portion is formed so as to surround on all sides the reference hole; and

wherein the stepped portion is formed in the same layer as the insulating layer and/or the conductive layer.