P1 write pole with shoulder formation

A magnetic disk drive head is disclosed including a write head, which includes a P1 layer having a pedestal portion, a gap layer formed on the P1 layer, and a P2 layer formed on the gap layer. The P1 layer includes a shoulder formation having a neck portion and a beveled portion. Also disclosed is a disk drive having a write head with a P1 layer with shoulder formation, and a method for fabricating a write pole for a magnetic recording head having a P1 layer with shoulder formation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to manufacture of heads for data storage devices and more specifically to a write head for a hard disk drive.

2. Description of the Prior Art

As the areal density of storage media steadily increases and track widths become narrower and closer together, there is more and more chance of interference from adjacent tracks. This interference has become so common that the acronym “ATI” for Adjacent Track Interference has been coined. This interference naturally increases write and read errors and is therefore undesirable.

A typical read/write head14is shown inFIG. 4, which is a side cut-away view of the slider16shown inFIG. 3. The magnetic head14includes a coil18, P1pole20, and a second pole P222which is separated from P1pole20by write gap23. The P1pole20, second pole P222and write gap23can be considered together to be included in the write head26. Magnetic flux is induced when current is passed through the coil18and then passes through the tip of the P222pole, across the gap23, through the recording medium (not shown) and returns through the P1pole20to complete the magnetic circuit. The magnetic flux thus acts to write data to the magnetic medium.

Magnetic flux flows in lines which are not straight, and thus tend to spread out slightly as they traverse the gap23separating the poles P120and P222. The amount of “spread” produced depends on the shape and configuration of the poles P120and P222.FIG. 5(prior art) shows a typical write head of the prior art including poles P120and P222and gap23. It is common practice that the P1pole20actually be composed of 2 or more layers, which in the example shown are two layers, designated as N142and N344. It is common practice that the N142layer be configured to be approximately the width of the P2pole22and gap23, and the N142layer having a straight portion43having a thickness of generally is approximately 2-4 times the thickness of the gap layer23. For ease of viewing, there has been no attempt to make the relative thicknesses of the layers in proper proportion.

The N3layer44is typically much wider than the N1layer42, and the N3layer44is also typically slightly beveled to channel magnetic flux more easily. The bevel angle α46is shown in the figure and generally is in the range of 5-15 degrees.

The magnetic flux48is shown spreading out as it leaves the P2pole22until it finally contacts the N3layer44of the P1pole20. This spread establishes the ATI. It is evident that this ATI is much wider than the P2pole22, and thus undesirable.

The design of write heads in general is a balance between narrowing undesirably broad ATI and having poles broad enough to allow adequate magnetic flux flow so that there is good field strength to accomplish satisfactory write or overwrite of data. As track widths become narrower and narrower, this balance becomes ever more delicate.

Thus there is a need for a magnetic write head which has smaller magnetic flux spread, thus creating less ATI, while allowing good magnetic flux channeling for good write and overwrite of data.

SUMMARY OF THE INVENTION

A preferred embodiment of the present invention is a magnetic disk drive head including a write head, which includes a P1layer having a pedestal portion, a gap layer formed on the P1layer, and a P2layer formed on the gap layer. The P1layer includes a shoulder formation having a neck portion and a beveled portion. Also disclosed is a disk drive having a write head with a P1layer with this shoulder formation, and a method for fabricating a write pole for a magnetic recording head having a P1layer with this shoulder formation.

It is an advantage of the present invention that it produces less ATI, and thus produces fewer read/write errors.

It is another advantage of the present invention that it produces greater manufacturing yields due to lower errors rates.

It is a further advantage of the present invention that it produces good magnetic flux channeling, and thus fewer write or overwrite errors in very narrow channel widths.

These and other features and advantages of the present invention will no doubt become apparent to those skilled in the art upon reading the following detailed description which makes reference to the several figures of the drawing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A magnetic disk drive2is shown generally inFIG. 1, having one or more magnetic data storage disks4, with data tracks6which are written and read by a data read/write device8. The data read/write device8includes an actuator arm10, and a suspension12which supports one or more magnetic heads14included in one or more sliders16.

FIG. 2shows a slider16in more detail being supported by suspension12. The magnetic head14is shown in dashed lines, and in more detail inFIGS. 3 and 4. The magnetic head14includes a coil18, P1pole20, and a second pole P222which is separated from P1pole20by write gap23. The P1pole20, second pole P222and write gap23can be considered together to be included in the write head26.

A read sensor40is sandwiched between a first shield, designated as S130and a second shield S234, and these elements together make up the read head28. An insulation layer32also separates S130and S234in the area behind the read sensor40. The magnetic head14flies on an air cushion between the surface of the disk4and the air bearing surface (ABS)24of the slider16.

As discussed above, magnetic flux is induced when current is passed through the coil18. The flux then passes through the tip of the P222pole, across the gap23, through the recording medium (not shown) and returns through the P1pole20to complete the magnetic circuit. The magnetic flux thus acts to write data to the magnetic medium.

Magnetic flux flows in lines which are not straight, and thus tend to spread out slightly as they traverse the gap23separating the poles P120and P222. The amount of “spread” produced depends on the shape and configuration of the poles P120and P222.

The novelty of the present invention may be best understood when compared to the prior art, as discussed above.FIG. 5(prior art) shows a typical write head of the prior art including poles P120and P222and gap23. It is common practice that the P1pole20actually be composed of 2 or more layers, which in the example shown are two layers, designated as N142and N344. It is common practice that the N142layer be configured to be approximately the width of the P2pole22and gap23. For ease of viewing, there has been no attempt to make the relative thicknesses of the layers in proper proportion.

The N3layer44is typically much wider than the N1layer42, and the N3layer44is also typically slightly beveled to channel magnetic flux more easily. The bevel angle α46is shown in the figure and generally is in the range of 5-15 degrees.

The N1layer42is also typically shaped to have a straight portion43and a beveled portion45. The thickness of the N1Straight portion43is generally 2-4 times the thickness of the gap layer23.

The magnetic flux48is shown spreading out as it leaves the P2pole22until it finally contacts the N1layer42or N3layer44of the P1pole20. This spread establishes the ATI. It is evident that this ATI is much wider than the P2pole22, and thus.

In contrast, the present write head60having a P1pole with shoulder formation62of the present invention is shown completed inFIGS. 6 and 13. The shoulder formation64includes portions of both N1layer66and N3layer68. The N1layer66has been shaped to have a straight portion70and a beveled portion72, and the N3layer68also includes a beveled portion74and a straight portion76, as well as an N3main body78. The N1and N3beveled portions72,74are preferably, but not necessarily, formed with a common bevel angle θ80which is preferably in the range of 10-70 degrees. The N3main body78has a bevel angle α82which is again preferably in the range of 5-15 degrees. The shoulder formation64thus includes N1straight portion70, N1beveled portion72, and N3beveled portion74. The N1straight portion70is preferably 0.5-2.5 times the thickness of the gap layer23. The entire shoulder formation64which includes the N1straight portion70, the N1beveled portion72, and N3beveled portion74, is preferably in the range of 2-5 times the thickness of the gap layer23. This compares to the thickness of the straight portion43of the N1layer42of the prior art, which is typically approximately 2-4 times the thickness of the gap layer23.

As shown inFIG. 6, the increased distance together with the beveled geometry of the layers allows the magnetic flux lines48to create smaller spread as they leave the P2pole22and they return to the P1pole62. The magnetic flux is much more confined in the present invention. This creates much less ATI, resulting in few errors, better production yields, and thus more efficient fabrication procedures. The geometry of the shoulder formation64also provides very good channeling of magnetic flux thus providing excellent write and overwrite of data.

The novel write head with shoulder formation60of the present invention also requires a novel method of fabrication to produce, which is shown inFIGS. 7-13, and which also introduces several optional variations in structure, which may be incorporated into the shoulder formation, as discussed below.

FIG. 7shows an N1layer66, preferably made of material chosen from a group consisting of CoFe, NiFe, CoFeNi, CoFeN, etc. which has been deposited on an N3layer68preferably made of material chosen from a group consisting of CoFe, NiFe, CoFeNi, etc.

FIG. 8shows a masking layer86, preferably made of photomask material, which has been formed on the N1layer66. The masking layer86preferably includes undercut regions88, and protects a portion of the N1layer66from milling by an ion milling source90.

AsFIG. 9shows, the ion milling and masking operation has been used to form an N1pedestal portion92, which has been shielded by the masking layer86from the ion milling beam.

FIG. 10shows that the masking layer (not shown) has been removed, the gap layer23has been deposited on the N1layer66including the N1pedestal portion92. Photoresist plating masks94have been formed, surrounding a slot96, which defines the initial P2track. The slot96is carefully aligned with the N1pedestal portion92, although separated from it by the gap layer23. The gap layer23is formed of Rh, Pt, Au, or Pd serving as the seed layer for electroplating.

FIG. 11shows that the slot96ofFIG. 10has been plated with material which is preferably chosen from a group consisting of CoFe, NiFe, CoFeNi, etc and which will form the P2pole22.

As an optional variation on this,FIG. 12shows that an additional seed layer98has been deposited on the gap layer23, and the P2pole22material has been plated on top of this seed layer98. This seed layer98can be included in the final shoulder formation, but is an optional variation.

InFIG. 13, the write head60has been shaped to its final configuration, preferably by ion milling. The final width of the P2pole22has been established, and the N1layer66has been shaped to have a straight portion70and a beveled portion72, and the N3layer68also includes a beveled portion74and a straight portion76, as well as an N3main body78, as discussed above. The N1and N3beveled portions72,74are preferably, but not necessarily, formed with a common bevel angle θ80which is preferably in the range of 10-70 degrees. The N3main body78has a bevel angle α82which is preferably in the range of 5-15 degrees. The shoulder formation64thus includes N1straight portion70, N1beveled portion72, and N3beveled portion74. For purposes of this discussion, the shoulder formation64will be considered to have a neck portion93, which is the straight portion above the beveled portions72,74, and which generally corresponds to the N1straight portion70. The shoulder formation64will also be considered to have a beveled portion95, which generally includes the N1beveled portion72and the N3beveled portion74, which preferably has the common bevel angle θ80, discussed above.

The neck portion93has a thickness97, which is preferably 0.5-2.5 times the thickness89of the gap layer23. The entire shoulder formation64which includes the neck portion93, and the beveled portion95, has a shoulder thickness91which is preferably in the range of 2-5 times the thickness89of the gap layer23. This may be compared to the thickness of the straight portion43of the N1layer42of the prior art (seeFIG. 5), which is typically approximately 2-4 times the thickness89of the gap layer23.

An optional seed layer98is shown, and also, as a second optional variation, a P2second layer99as it is also possible that the P2pole be a bi-layer structure. It is also possible that the P2be more than two layers, although this is not shown in the figure.

While the present invention has been shown and described with regard to certain preferred embodiments, it is to be understood that modifications in form and detail will no doubt be developed by those skilled in the art upon reviewing this disclosure. It is therefore intended that the following claims cover all such alterations and modifications that nevertheless include the true spirit and scope of the inventive features of the present invention.