1. Field of the Invention
The invention relates to an electrical lapping guide (ELG) for magnetic tape heads, and methods for making same.
2. Background Art
Magnetic tape heads typically include tape head elements formed from films that are deposited upon a substrate. The elements are machined to a desired height by a grinding process that is referred to as lapping. The desired height is referred to as a target stripe height for magnetic tape heads that have a magneto-resistive reader. The height is also referred to as a throat height for magnetic tape heads that are thin-film writers.
The prior art has utilized electrical lapping guides (ELG) to help define the target height of the tape head elements upon the substrate. Typically, one ELG is provided on each side of the tape head elements and is lapped with the tape head elements for measuring the target height of the tape head elements and for balance control across both lateral sides of the tape head elements. Since there is no real-time and cost-effective method for measuring the target height for a production tape head, and since both the ELG and reader are on the same layers of materials and share the same zero stripe height, the target height, or final stripe height (Ht), is usually calculated and obtained from a resistance feedback equation Ro×Ho=Rt×Ht, wherein Ro is an initial resistance at an initial stripe height Ho, and Rt is a measured target resistance at the final stripe height Ht.