Fabrication of self-aligned side-by-side read/write head by using selective dry etching
Original Publication Date: 2000-Feb-01
Included in the Prior Art Database: 2003-Jun-18
Main Idea One problem associated with recording head fabrication is the alignment of the throat of a write head and the stripe of a read sensor since they are separated by several layers and are defined by different photo steps. Building read and write head side by side offers the possibility of defining the read sensor stripe and write throat simultaneously. However, the requirement for patterning (usually milling) is different. While write head throat requires a depth of 2000 angstrom or more, read sensor milling only needs 200 300 angstrom of milling. Defining stripe and throat with the same milling process would therefore result in gross overmill of the read sensor area, leading to sensor-to-shield short due to complete loss of gap 1 and redeposition, as shown in Figure 1. Figure 2 shows the disclosed method. Structurewise, the first shield and the first pole piece are shared. Gap 1 and sensor are deposited over S1. An etch stop layer such as carbon is then deposited over the sensor area. Next, a photolithography step using a mask with throat and stripe aligned is conducted. Then the patterned structure is subject to ion milling to define the write throat. In the read sensor area, since the milling rate of carbon is several times slower than that of NiFe, the thin carbon layer will not be consumed completely during throat definition. Upon the completion of throat milling, with the resist mask still in place, a selective dry etch process containing O2 or Ar/H2 is used to remove selectively the remaining carbon layer. Still with resist mask in place , ion milling is then used to accomplish read sensor stripe definition. Using this method, write throat and read stripe are self-aligned and the overmilling of the read sensor area is avoided.