Pole Tip Recession (PTR) measurements with high accuracy, precision, and throughput

Accurate and precise Pole Tip Recession (PTR) measurement is vital to meet the magnetic spacing requirement and to achieve higher electrical test yield at the Head-Gimbel Assembly (HGA). To obtain a high throughput in PTR measurements, optical interferometers are the most commonly used techniques. PTR values determined by optical tools will however need to be corrected for material dissimilarities and the roughness effects. The correction factor or "PTR offset" values are influenced by variations in the optical properties of the pole tip and ABS surfaces. The changes in PTR offsets values due to variation in slider surface roughness and overcoat properties is the subject of this paper.