Metal fusion bonding – Process – Plural joints
Reexamination Certificate
2001-06-26
2003-04-08
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
Plural joints
C228S175000, C228S176000, C228S177000, C228S178000, C360S240000, C360S245900, C361S008000, C361S055000
Reexamination Certificate
active
06543673
ABSTRACT:
FIELD OF THE INVENTION
This application relates generally to preventing electrostatic discharge in sensitive electrical components and more particularly to a shunt connection system for protecting sensitive components during manufacturing procedures.
BACKGROUND OF THE INVENTION
Electrostatic discharge (ESD) during manufacturing of many electrical components often causes component failure. Electrostatic potential may build through handling of the component during various manufacturing and testing procedures. The electrostatic potential around the component may reach several thousands of volts, and the component is typically designed for a much smaller voltage drop. The discharge current through the component from the electrostatic potential renders it unusable.
For example, in disc drives an ESD sensitive magnetoresistive read/inductive write head is used to read data from, and write data to, a magnetic disc. The read/write head is mounted to a movable arm that transports the head to the appropriate location over the disc. The read/write head passes electrical signals through a flexible circuit positioned on the movable arm and connected to a printed circuit board. The flexible circuit has one portion that is attached to the suspension on the arm and electrically connected to the read/write head. This flex on suspension (FOS) portion is also electrically connected to a printed circuit cable assembly (PCCA) that is electrically connected to the printed circuit board. The PCCA permits the arm to move relative to the preamplifier printed circuit board while maintaining electrical continuity.
The FOS coupled to the read/write head must be tested for proper operation before a head gimbal assembly and/or head stack assembly including the FOS and read/write head is fully installed in the disc drive. The manufacturing process requires shunting the leads of the FOS from the read/write head together to prevent electrostatic build-up prior to testing, then removing the shunt so that the FOS and read/write head can be tested. After testing, the leads must be reshunted to reestablish ESD protection. The conventional reshunting process involves manually soldering the leads together where the first shunt was removed. After reshunting occurs, the FOS is then connected to the PCCA by manually removing the shunted portion and soldering the FOS contacts to the PCCA contacts. However, manually removing the shunted portion of the FOS often results in ESD through the read/write head rendering it unusable.
Accordingly there is a need for a system for protecting sensitive components from ESD during the manufacturing and testing processes.
SUMMARY OF THE INVENTION
Against this backdrop the present invention has been developed. Embodiments of the present invention provide ESD protection during the manufacturing process by shunting the electrical leads and then utilizing the material used for shunting to establish an electrical bond to an additional electrical component.
The present invention may be viewed as a method for protecting an electrical component from electrostatic discharge prior to being electrically connected to an additional component. The method involves 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. The method further involves 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. The method additionally involves 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.
The present invention may also be viewed as a system for preventing electrostatic discharge through an electrical component prior to electrically connecting the electrical component to an additional component. The system includes a solder conductor shunting one or more conductive leads extending from the electrical component to a second conductive lead extending from the electrical component. The system also includes electrical contacts on the additional component contacting the one or more conductive leads, the second conductive lead, and the one or more solder conductors. The system additionally includes 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.
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Lennard Michael Henry
Rugg William Leon
Edmondson L.
Merchant & Gould P.C.
Seagate Technology LLC
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