| 摘要 |
PURPOSE: A resistive shunt ESD(Electrostatic Discharge) and EOS(Electrical Overstress) protection for recording heads is provided to minimize the damage to an (G)MR(Magnetoresistive) sensor caused by the ESD through or EOS of the (G)MR sensor element, by using resistors to provide a low resistance bypass to the (G)MR sensor, and to provide a method for protecting the (G)MR sensor from ESD and EOS damage but at the same time allow the (G)MR sensor element to be tested at various stages in the manufacturing process. CONSTITUTION: Two resistors(10,12) are connected in series, across and in parallel with the (G)MR head, represented by a resistor(14). The resistors(10,12) form a low resistance bypass that provides the protection against ESD or EOS by shunting current away from the (G)MR head(14). Electrical probing points(16) are provided at the nodes between the individual resistors, as well as the endpoints of the resistors. These probing points(16) consist of separate electrically conductive pads, or consist of two probing locations on a single such pad. Using a nonzero shunt resistance provides two different approaches to the testability of the (G)MR head. In the simplest approach, the resistance of the traces used to make the resistors(10,12) is measured in various spots on the wafer by using test structures. These test structures are made of the same material as the resistors with the same shape and size in order to allow a close estimate of the resistance of the resistors(10,12). Once the test structure's resistance is known, the resistance value of the resistors(10,12) surrounding these test structures is known with reasonably accuracy. The effects of the resistors(10,12) are from the measurements of resistance and amplitude during the testing of the (G)MR head by calculation of the value of the (G)MR resistor(14).
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