Patent ID: 7067066

Claim:
A method of manufacturing a thin-film magnetic head, the head comprising: first and second magnetic layers each including a magnetic pole and magnetically coupled to each other, the magnetic poles facing each other with a gap layer in between and positioned to face toward a recording medium; and a thin-film coil portion disposed between the two magnetic layers with an insulating film in between; the first magnetic layer including a first magnetic layer portion having a first uniform width portion that defines a track width, and a second magnetic layer portion extending over a region where the thin-film coil portion is disposed and magnetically coupled to the first magnetic layer portion, the second magnetic layer including a second uniform width portion formed in a similar position and opposite to the first uniform width portion of the first magnetic layer, the method comprising: a first step of forming the first magnetic material layer on the gap layer made of aluminum oxide, and patterning the first magnetic material layer through the use of a first mask made of aluminum oxide by reactive ion etching so as to form at least the first uniform width portion of the first magnetic layer; a second step of selectively removing a region of the gap layer excluding a portion that includes to the first uniform width portion of the first magnetic layer by reactive ion etching; and a third step of patterning a second magnetic material layer by reactive ion etching so as to form at least the second uniform width portion of the second magnetic layer, wherein in the first, second, and third steps, the reactive ion etching is performed in a chlorine gas atmosphere at a temperature ranging from 150° C. to 250 ° C.