Method of manufacturing a double sided flex circuit for a disk drive wherein a first side lead provides an etching mask for a second side lead

• US 9,060,420 B2
• Filed: 05/30/2011
• Issued: 06/16/2015
• Est. Priority Date: 11/01/2007
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Hogg, Dennis W.
• Primary Examiner(s): Tugbang, A. Dexter
• Application Number:
  US13/118,545
• Publication Number:
  US 20110226729A1
• Time in Patent Office: 1,478 Days
• Field of Search: 298/29, 298/46, 298/47, 298/42, 298/52, 296/030.3, 430/313, 430/318, 216/13, 216/18, 216/39, 216/48
• US Class Current: 1/1
• CPC Class Codes: G11B 5/486 with provision for mounting or arranging electrical conducting means or circuits on or along the arm assembly
• CPC Class Codes: H05K 2201/0108 Transparent
• CPC Class Codes: H05K 2201/09672 Superposed layout, i.e. in different planes parallel traces in one plane H05K2201/09236
• CPC Class Codes: H05K 2203/0551 Exposure mask directly printed on the PCB
• CPC Class Codes: H05K 3/0082 characterised by the exposure method of radiation-sensitive masks
• CPC Class Codes: H05K 3/048 using a lift-off resist pattern or a release layer pattern
• CPC Class Codes: H05K 3/06 the conductive material being removed chemically or electrolytically, e.g. by photo-etch process semi-additive methods H05K3/108
• CPC Class Codes: H05K 3/184 using masks
• CPC Class Codes: Y10T 29/49025 Making disc drive
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/49147 Assembling terminal to base
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base
• CPC Class Codes: Y10T 29/49156 with selective destruction of conductive paths
• CPC Class Codes: Y10T 29/49165 by forming conductive walled aperture in base

Abstract

A method of manufacturing a flex circuit is disclosed for a disk drive comprising a disk, a head actuated radially over the disk, and control circuitry. The flex circuit is for electrically coupling the head to the control circuitry and comprises a substrate. An electrical coating applied to a first side of the substrate is etched to form a first electrical lead. The first side of the substrate is irradiated with radiation such that the first electrical lead masks the radiation from passing through the substrate to prevent curing of a photoresist applied to the second side of the substrate to form an uncured photoresist and a cured photoresist on the second side of the substrate. The uncured photoresist is removed from the second side of the substrate to form a groove, and the groove is filled with electrically conductive material to form the second electrical lead.

Claims

1. A method of manufacturing a flex circuit for a disk drive, the disk drive comprising a disk, a head actuated radially over the disk, and control circuitry, wherein the flex circuit is for electrically coupling the head to the control circuitry and comprises a substrate, the method comprising:

etching an electrical coating applied to a first side of the substrate to form a first electrical lead;

irradiating the first side of the substrate with radiation such that the first electrical lead masks the radiation from passing through the substrate to prevent curing of a photoresist applied to a second side of the substrate, wherein the photoresist is formed into an uncured photoresist and a cured photoresist on the second side of the substrate;

removing the uncured photoresist from the second side of the substrate to form a groove; and

filling the groove with electrically conductive material to form a second electrical lead.

2. The method as recited in claim 1, wherein the first electrical lead is substantially aligned with the second electrical lead such that the substrate forms a capacitive dielectric.

3. The method as recited in claim 1, wherein the substrate comprises a polyimide.

4. The method as recited in claim 3, wherein the polyimide is sufficiently transparent to pass the radiation.

5. The method as recited in claim 4, wherein the radiation comprises ultraviolet light.

6. The method as recited in claim 4, wherein the radiation comprises visible light.