Flexible circuit with electrostatic damage limiting feature

Microflex circuits are widely used for applications such as integrated circuit (IC) packages, inkjet cartridges, hard disk drives (HDD), medical devices and other advanced flex circuit-based electrical connections. Such connections require electrical static discharge (ESD) protection during product manufacturing and assembly comprising insulating materials (plastic, polymers) and manual operations. ESD concerns are amplified in hard disk drive manufacturing environments and applications, especially for head gimbal assemblies (HGA) using giant magnetorestrictive read (GMR) sensors in the sliders. For current commercial hard disk drive (HDD) product platforms at 40 or 60 gigabit/in [(GB)/in ], electrostatic discharge protection is required to protect these sensitive read heads. ESD requirements are specified in terms of surface resistivity and tribocharge voltage control on all incoming components and nearby process/assembly workstations. The specifications from many HDD manufacturers indicated surface resistivities should preferably be controlled within a range of from about 10 ohms to about 10 ohms, and maximum surface voltage from tribocharging must be less than 10 Volts (V). A flexible circuit incorporating an electrostatic discharge limiting feature, comprising a dielectric substrate selected from polyimide or liquid crystal polymer film having at least one conductive trace coated on at least one surface of the substrate wherein the discharge limiting feature includes a thin conductive polymer coating selectively applied over a at least a portion of the non-critical region of the circuit, said feature reducing the surface resistivity of the circuit to about 10ohms to about 10ohms and having tribocharging of less than about 50 V.