Magnetic sensing element having reactive-ion-etching stop layer and process for producing same

A magnetic sensing element comprising:

• a bottom shield layer;
• a top shield layer;
• a laminate including at least a first reactive-ion-etching stop layer;
• bias layers at both sides of the laminate in the track width direction;
• and
• second reactive-ion-etching stop layers each disposed on at least part of the corresponding bias layer, the second reactive-ion-etching stop layers functioning as stop layers for reactive ion etching, wherein the laminate, the bias layers, the first reactive-ion-etching stop layer, and the second reactive-ion-etching stop layers are disposed between the bottom shield layer and the top shield layer;
• wherein the top face of the first reactive-ion-etching stop layer and at least part of the top face of each second reactive-ion-etching stop layer are disposed at the same height and are each a planarized surface.