Disk drive head stack assembly having a flexible printed circuit with bond pads having reduced capacitance

A head stack assembly (HSA) for a disk drive, the HSA comprising:

• an actuator body, at least one actuator arm extending from the actuator body, and a flexible printed circuit (FPC), the FPC including
• a FPC conductive layer, the FPC conductive layer including a plurality of FPC traces defined therein, each of the plurality of FPC traces being electrically conductive and having a distal portion that terminates at a respective one of a plurality of FPC bond pads that are electrically conductive;
• a metallic FPC stiffener layer having a FPC stiffener layer surface that underlies and faces the FPC bond pads, the FPC stiffener layer surface including a plurality of recessions having a depth of at least 25 microns;
• and
• a FPC dielectric layer disposed between the FPC conductive layer and the metallic FPC stiffener layer;
• and
• at least one head gimbal assembly comprising
• a read head;
• and
• a suspension assembly attached to the at least one actuator arm, the suspension assembly comprising
• a load beam, and
• a laminate flexure that includes a plurality of electrically conductive flexure traces that each terminate at a respective one of a plurality of electrically conductive flexure bond pads, the plurality of electrically conductive flexure bond pads being bonded to the plurality of FPC bond pads.

A head stack assembly (HSA) for a disk drive, the HSA comprising:

• an actuator body, at least one actuator arm extending from the actuator body, and a flexible printed circuit (FPC), the FPC including
• a FPC conductive layer, the FPC conductive layer including a plurality of FPC traces defined therein, each of the plurality of FPC traces being electrically conductive and having a distal portion that terminates at a respective one of a plurality of FPC bond pads that are electrically conductive;
• a metallic FPC stiffener layer that underlies the FPC bond pads;
• and
• a FPC dielectric layer disposed between the FPC conductive layer and the metallic FPC stiffener layer;
• wherein at least one of the plurality of FPC bond pads is internally patterned to define a FPC bond pad mesh with a plurality of openings therethrough;
• and
• at least one head gimbal assembly comprising
• a read head;
• and
• a suspension assembly attached to the at least one actuator arm, the suspension assembly comprising
• a load beam, and
• a laminate flexure that includes a plurality of electrically conductive flexure traces that each terminate at a respective one of a plurality of electrically conductive flexure bond pads, the plurality of electrically conductive flexure bond pads being bonded to the plurality of FPC bond pads.

A head stack assembly (HSA) for a disk drive, the HSA comprising:

• an actuator body, at least one actuator arm extending from the actuator body, and a flexible printed circuit (FPC), the FPC including
• a FPC conductive layer, the FPC conductive layer including a plurality of FPC traces defined therein, each of the plurality of FPC traces being electrically conductive and having a distal portion that terminates at a respective one of a plurality of FPC bond pads that are electrically conductive;
• a metallic FPC stiffener layer that underlies the FPC bond pads;
• and
• a FPC dielectric layer disposed between the FPC conductive layer and the metallic FPC stiffener layer;
• wherein the FPC includes a means for reducing the electrical capacitance between the FPC bond pads and the metallic FPC stiffener layer;
• and
• at least one head gimbal assembly comprising
• a read head;
• and
• a suspension assembly attached to the at least one actuator arm, the suspension assembly comprising
• a load beam, and
• a laminate flexure that includes a plurality of electrically conductive flexure traces that each terminate at a respective one of a plurality of electrically conductive flexure bond pads, the plurality of electrically conductive flexure bond pads being bonded to the plurality of FPC bond pads.