Dissolving shunt connection system for ESD sensitive components

• US 6,543,673 B2
• Filed: 06/26/2001
• Issued: 04/08/2003
• Est. Priority Date: 11/06/2000
• Status: Expired due to Fees

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Rugg, William Leon, Lennard, Michael Henry
• Primary Examiner(s): Dunn, Tom
• Assistant Examiner(s): EDMONDSON, LYNNE RENEE
• Application Number:
  US09/892,303
• Publication Number:
  US 20020053590A1
• Time in Patent Office: 651 Days
• Field of Search: 228/179.1, 228/180.1, 228/180.21, 228/180.22, 228/173.1, 228/102, 228/103, 228/175-178, 228/189, 296/030--60, 360/103-106, 360/97.02, 360/245.9, 360/128, 360/240, 219/243, 361/8, 361/55
• US Class Current: 228/179.1
• CPC Class Codes: G11B 5/40 Protective measures on heads, e.g. against excessive temperature G11B5/31 takes precedence; protection against wear G11B5/255 ; protective structure of the head: see under structures, e.g. G11B5/3106
• CPC Class Codes: G11B 5/4806 specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives G11B5/488 - G11B5/54 take precedence
• 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 1/0259 Electrostatic discharge [ESD] protection
• CPC Class Codes: H05K 1/0268 for electrical inspection or testing
• CPC Class Codes: H05K 2201/0305 Solder used for other purposes than connections between PCB or components, e.g. for filling vias or for programmable patterns
• CPC Class Codes: H05K 2201/0909 Preformed cutting or breaking line
• CPC Class Codes: H05K 2203/0405 Solder foil, tape or wire
• CPC Class Codes: H05K 2203/175 Configurations of connections suitable for easy deletion, e.g. modifiable circuits or temporary conductors for electroplating; Processes for deleting connections
• CPC Class Codes: H05K 3/363 by soldering

Abstract

A method and system are disclosed for protecting an electrical component from electrostatic discharge prior to its electrical connection to an additional component. Specifically, a flex on suspension circuit of a disc drive that is electrically connected to the read/write head is disclosed as having exposed leads for connection to a printed circuit cable assembly. The exposed leads are shunted with a solder conductor such as solder tape after testing of the circuit and head to prevent electrostatic build-up across the read and write elements. The flex on suspension circuit is then electrically connected to the printed circuit assembly cable by reflowing the solder conductor to bond the exposed leads of the flex on suspension circuit to the electrical contacts of the printed circuit assembly cable and also to remove the electrical short established between the exposed leads by the solder conductor.

Claims

1. A method for protecting an electrical component from electrostatic discharge prior to and during connection of the electrical component to an additional component, the method comprising steps of:

a) shunting one or more conductive leads extending from the electrical component to a second conductive lead extending from the electrical component with one or more solder conductors;

b) contacting the one or more conductive leads, the second conductive lead, and the one or more solder conductors to electrical contacts of the additional component; and

c) heating the one or more solder conductors until the one or more solder conductors electrically bond the one or more conductive leads and the second conductive lead to the electrical contacts of the additional component and until the one or more solder conductors no longer shunt the one or more conductive leads to the second conductive lead.

2. The method of claim 1, wherein the electrical component is a flex on suspension circuit electrically connected to a read/write head.

3. The method of claim 2, wherein the read/write head has a read element and a write element, the shunting step a) comprising a step of:

a)(i) shunting conductive leads extending from the read element together with conductive leads extending from the write element.

4. The method of claim 2, wherein the read/write head has a read element and a write element, the shunting step a) comprising a step of:

a)(ii) shunting together conductive leads extending from the read element; and

a)(iii) separately shunting together conductive leads extending from the write element.

5. The method of claim 2, wherein the flex on suspension circuit has an opening exposing the conductive leads, and the shunting step a), the contacting step b), and the heating step c) are performed within the opening.

6. The method of claim 1, wherein the one or more solder conductors include a strip of solder tape, and the shunting step a) comprises a step of:

a)(iv) pressing the solder tape onto and across the one or more conductive leads and the second conductive lead.

7. The method of claim 6, wherein the strip of solder tape is of a predetermined length.

8. The method of claim 1, further comprising steps of:

d) prior to shunting step a), shunting the one or more conductive leads to the second conductive lead with an electrical conductor;

e) prior to shunting step a), removing the electrical conductor shunting the one or more conductive leads to the second conductive lead; and

f) prior to shunting step a), testing the operation of the electrical component by applying test signals across the one or more conductive leads and the second conductive lead.

9. The method of claim 8, wherein the electrical component has test pads electrically connected to the one or more conductive leads and the second conductive lead, the testing step f) comprising a step of:

f)(i) applying the test signals to the test pads.

10. The method of claim 9, further comprising a step of:

g) prior to contacting step b), removing the test pads from the electrical component.

11. A system for preventing electrostatic discharge through an electrical component prior to and during connection of the electrical component to an additional component, comprising:

a solder conductor shunting one or more conductive leads extending from the electrical component to a second conductive lead extending from the electrical component;

electrical contacts on the additional component contacting the one or more conductive leads, the second conductive lead, and the one or more solder conductors; and

heat applied to the one or more solder conductors until the one or more solder conductors electrically bond the one or more conductive leads and the second conductive lead to the electrical contacts of the additional component and until the one or more solder conductors no longer shunt the one or more conductive leads to the second conductive lead.

12. The system of claim 11, wherein the electrical component is a flex on suspension circuit electrically connected to a read/write head.

13. The system of claim 12, wherein the read/write head has a read element and a write element, and the solder conductor shunts together the conductive leads extending from the read element with conductive leads extending from the write element.

14. The system of claim 12, wherein the flex on suspension circuit has an opening exposing the conductive leads and wherein the solder conductor, the electrical contacts, and the heat are provided within the opening.

15. The system of claim 11, wherein the solder conductor includes a strip of solder tape pressed onto and across the one or more conductive leads and the second conductive lead.

16. The system of claim 15, wherein the strip of solder tape is of a predetermined length.

17. The system of claim 11, further comprising:

an electrical conductor shunting the one or more conductive leads to the second conductive lead prior to application of the solder conductor; and

test signals applied across the one or more conductive leads and the second conductive lead after removal of the electrical conductor and prior to application of the solder conductor to the one or more conductive leads and the second conductive lead.

18. The system of claim 17, wherein the electrical component has test pads electrically connected to the one or more conductive leads and the second conductive lead and wherein the test signals are applied to the test pads.

19. The system of claim 11, wherein the electrical component is a flying lead flex on suspension circuit electrically connected to a read/write head.

20. A system for preventing electrostatic discharge through an electrical component prior to and during electrically connecting the electrical component to an additional component, comprising:

a plurality of conductive leads extending from the electrical component; and

a conductor means for i) providing a shunt between one or more conductive leads of the plurality and a second conductive lead of the plurality prior to electrical connection of one or more conductive leads to the additional component, and ii) providing an electrical connection between one or more conductive leads and the additional component following removal of the shunt between the one or more conductive leads and the second conductive lead.

21. The system of claim 20, wherein the conductor means is operable to electrically bond the one or more conductive leads to the additional component upon application of a solder reflow process to the conductor means.

22. The system of claim 21, wherein the electrical component comprises a disc drive flex on suspension circuit.

23. The system of claim 20, wherein the conductor means comprises solder tape.

24. The system of claim 20, wherein the electrical component includes test pads electrically connected to the one or more conductive leads and the second conductive lead.

25. The system of claim 24, wherein the flex on suspension circuit includes means for exposing the conductive leads.