P1 write pole with shoulder formation

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 head 14 is shown in FIG. 4 , which is a side cut-away view of the slider 16 shown in FIG. 3 . The magnetic head 14 includes a coil 18 , P 1 pole 20 , and a second pole P 2 22 which is separated from P 1 pole 20 by write gap 23 . The P 1 pole 20 , second pole P 2 22 and write gap 23 can be considered together to be included in the write head 26 . Magnetic flux is induced when current is passed through the coil 18 and then passes through the tip of the P 2 22 pole, across the gap 23 , through the recording medium (not shown) and returns through the P 1 pole 20 to 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 gap 23 separating the poles P 1 20 and P 2 22 . The amount of “spread” produced depends on the shape and configuration of the poles P 1 20 and P 2 22 . FIG. 5 (prior art) shows a typical write head of the prior art including poles P 1 20 and P 2 22 and gap 23 . It is common practice that the P 1 pole 20 actually be composed of 2 or more layers, which in the example shown are two layers, designated as N 1 42 and N 3 44 . It is common practice that the N 1 42 layer be configured to be approximately the width of the P 2 pole 22 and gap 23 , and the N 1 42 layer having a straight portion 43 having a thickness of generally is approximately 2-4 times the thickness of the gap layer 23 . For ease of viewing, there has been no attempt to make the relative thicknesses of the layers in proper proportion.

The N 3 layer 44 is typically much wider than the N 1 layer 42 , and the N 3 layer 44 is also typically slightly beveled to channel magnetic flux more easily. The bevel angle α 46 is shown in the figure and generally is in the range of 5-15 degrees.

The magnetic flux 48 is shown spreading out as it leaves the P 2 pole 22 until it finally contacts the N 3 layer 44 of the P 1 pole 20 . This spread establishes the ATI. It is evident that this ATI is much wider than the P 2 pole 22 , 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.

A preferred embodiment of the present invention is a magnetic disk drive head including a write head, which includes a P 1 layer having a pedestal portion, a gap layer formed on the P 1 layer, and a P 2 layer formed on the gap layer. The P 1 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 P 1 layer with this shoulder formation, and a method for fabricating a write pole for a magnetic recording head having a P 1 layer 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.

The following drawings are not made to scale as an actual device, and are provided for illustration of the invention described herein.

FIG. 1 shows a top plan view of an exemplary disk drive;

FIG. 2 illustrates a perspective view of view of an exemplary slider and suspension;

FIG. 3 shows a top plan view of an exemplary read/write head;

FIG. 4 is a cross-section view of an exemplary read/write head;

FIG. 5 shows front plan views of the magnetic flux patterns between P 1 and P 2 poles of a write head of the prior art;

FIG. 6 shows front plan views of the magnetic flux patterns between the P 2 pole and P 1 pole with shoulder formation of the present invention; and

FIGS. 7-13 show front plan views of various stages in the fabrication of the write head of the present invention.

A magnetic disk drive 2 is shown generally in FIG. 1 , having one or more magnetic data storage disks 4 , with data tracks 6 which are written and read by a data read/write device 8 . The data read/write device 8 includes an actuator arm 10 , and a suspension 12 which supports one or more magnetic heads 14 included in one or more sliders 16 .

FIG. 2 shows a slider 16 in more detail being supported by suspension 12 . The magnetic head 14 is shown in dashed lines, and in more detail in FIGS. 3 and 4 . The magnetic head 14 includes a coil 18 , P 1 pole 20 , and a second pole P 2 22 which is separated from P 1 pole 20 by write gap 23 . The P 1 pole 20 , second pole P 2 22 and write gap 23 can be considered together to be included in the write head 26 .

A read sensor 40 is sandwiched between a first shield, designated as S 1 30 and a second shield S 2 34 , and these elements together make up the read head 28 . An insulation layer 32 also separates S 1 30 and S 2 34 in the area behind the read sensor 40 . The magnetic head 14 flies on an air cushion between the surface of the disk 4 and the air bearing surface (ABS) 24 of the slider 16 .

As discussed above, magnetic flux is induced when current is passed through the coil 18 . The flux then passes through the tip of the P 2 22 pole, across the gap 23 , through the recording medium (not shown) and returns through the P 1 pole 20 to 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 gap 23 separating the poles P 1 20 and P 2 22 . The amount of “spread” produced depends on the shape and configuration of the poles P 1 20 and P 2 22 .

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 P 1 20 and P 2 22 and gap 23 . It is common practice that the P 1 pole 20 actually be composed of 2 or more layers, which in the example shown are two layers, designated as N 1 42 and N 3 44 . It is common practice that the N 1 42 layer be configured to be approximately the width of the P 2 pole 22 and gap 23 . For ease of viewing, there has been no attempt to make the relative thicknesses of the layers in proper proportion.

The N 3 layer 44 is typically much wider than the N 1 layer 42 , and the N 3 layer 44 is also typically slightly beveled to channel magnetic flux more easily. The bevel angle α 46 is shown in the figure and generally is in the range of 5-15 degrees.

The N 1 layer 42 is also typically shaped to have a straight portion 43 and a beveled portion 45 . The thickness of the N 1 Straight portion 43 is generally 2-4 times the thickness of the gap layer 23 .

The magnetic flux 48 is shown spreading out as it leaves the P 2 pole 22 until it finally contacts the N 1 layer 42 or N 3 layer 44 of the P 1 pole 20 . This spread establishes the ATI. It is evident that this ATI is much wider than the P 2 pole 22 , and thus.

In contrast, the present write head 60 having a P 1 pole with shoulder formation 62 of the present invention is shown completed in FIGS. 6 and 13 . The shoulder formation 64 includes portions of both N 1 layer 66 and N 3 layer 68 . The N 1 layer 66 has been shaped to have a straight portion 70 and a beveled portion 72 , and the N 3 layer 68 also includes a beveled portion 74 and a straight portion 76 , as well as an N 3 main body 78 . The N 1 and N 3 beveled portions 72 , 74 are preferably, but not necessarily, formed with a common bevel angle θ 80 which is preferably in the range of 10-70 degrees. The N 3 main body 78 has a bevel angle α 82 which is again preferably in the range of 5-15 degrees. The shoulder formation 64 thus includes N 1 straight portion 70 , N 1 beveled portion 72 , and N 3 beveled portion 74 . The N 1 straight portion 70 is preferably 0.5-2.5 times the thickness of the gap layer 23 . The entire shoulder formation 64 which includes the N 1 straight portion 70 , the N 1 beveled portion 72 , and N 3 beveled portion 74 , is preferably in the range of 2-5 times the thickness of the gap layer 23 . This compares to the thickness of the straight portion 43 of the N 1 layer 42 of the prior art, which is typically approximately 2-4 times the thickness of the gap layer 23 .

As shown in FIG. 6 , the increased distance together with the beveled geometry of the layers allows the magnetic flux lines 48 to create smaller spread as they leave the P 2 pole 22 and they return to the P 1 pole 62 . 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 formation 64 also provides very good channeling of magnetic flux thus providing excellent write and overwrite of data.

The novel write head with shoulder formation 60 of the present invention also requires a novel method of fabrication to produce, which is shown in FIGS. 7-13 , and which also introduces several optional variations in structure, which may be incorporated into the shoulder formation, as discussed below.

FIG. 7 shows an N 1 layer 66 , preferably made of material chosen from a group consisting of CoFe, NiFe, CoFeNi, CoFeN, etc. which has been deposited on an N 3 layer 68 preferably made of material chosen from a group consisting of CoFe, NiFe, CoFeNi, etc.

FIG. 8 shows a masking layer 86 , preferably made of photomask material, which has been formed on the N 1 layer 66 . The masking layer 86 preferably includes undercut regions 88 , and protects a portion of the N 1 layer 66 from milling by an ion milling source 90 .

As FIG. 9 shows, the ion milling and masking operation has been used to form an N 1 pedestal portion 92 , which has been shielded by the masking layer 86 from the ion milling beam.

FIG. 10 shows that the masking layer (not shown) has been removed, the gap layer 23 has been deposited on the N 1 layer 66 including the N 1 pedestal portion 92 . Photoresist plating masks 94 have been formed, surrounding a slot 96 , which defines the initial P 2 track. The slot 96 is carefully aligned with the N 1 pedestal portion 92 , although separated from it by the gap layer 23 . The gap layer 23 is formed of Rh, Pt, Au, or Pd serving as the seed layer for electroplating.

FIG. 11 shows that the slot 96 of FIG. 10 has been plated with material which is preferably chosen from a group consisting of CoFe, NiFe, CoFeNi, etc and which will form the P 2 pole 22 .

As an optional variation on this, FIG. 12 shows that an additional seed layer 98 has been deposited on the gap layer 23 , and the P 2 pole 22 material has been plated on top of this seed layer 98 . This seed layer 98 can be included in the final shoulder formation, but is an optional variation.

In FIG. 13 , the write head 60 has been shaped to its final configuration, preferably by ion milling. The final width of the P 2 pole 22 has been established, and the N 1 layer 66 has been shaped to have a straight portion 70 and a beveled portion 72 , and the N 3 layer 68 also includes a beveled portion 74 and a straight portion 76 , as well as an N 3 main body 78 , as discussed above. The N 1 and N 3 beveled portions 72 , 74 are preferably, but not necessarily, formed with a common bevel angle θ 80 which is preferably in the range of 10-70 degrees. The N 3 main body 78 has a bevel angle α 82 which is preferably in the range of 5-15 degrees. The shoulder formation 64 thus includes N 1 straight portion 70 , N 1 beveled portion 72 , and N 3 beveled portion 74 . For purposes of this discussion, the shoulder formation 64 will be considered to have a neck portion 93 , which is the straight portion above the beveled portions 72 , 74 , and which generally corresponds to the N 1 straight portion 70 . The shoulder formation 64 will also be considered to have a beveled portion 95 , which generally includes the N 1 beveled portion 72 and the N 3 beveled portion 74 , which preferably has the common bevel angle θ 80 , discussed above.

The neck portion 93 has a thickness 97 , which is preferably 0.5-2.5 times the thickness 89 of the gap layer 23 . The entire shoulder formation 64 which includes the neck portion 93 , and the beveled portion 95 , has a shoulder thickness 91 which is preferably in the range of 2-5 times the thickness 89 of the gap layer 23 . This may be compared to the thickness of the straight portion 43 of the N 1 layer 42 of the prior art (see FIG. 5 ), which is typically approximately 2-4 times the thickness 89 of the gap layer 23 .

An optional seed layer 98 is shown, and also, as a second optional variation, a P 2 second layer 99 as it is also possible that the P 2 pole be a bi-layer structure. It is also possible that the P 2 be 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.