Method for bonding slider row bars for photolithography process

Certain example embodiments relate to a method for bonding slider row bars for a photolithography process. A holding device having a sticky surface is formed. A plurality of slider row bars is provided, with each having a first surface for forming an air bearing surface and a second surface opposite the first surface. The slider row bars are secured to the holding device with their first surfaces facing the sticky surface so that the first surfaces of the slider row bars are aligned each other. The slider row bars are bonded together by an encapsulating glue. A carrier is provided, and the carrier is bonded to the second surfaces of the slider row bars. The holding device is removed. The example embodiments also can be used to manufacture sliders.

FIELD OF THE INVENTION

The present invention relates to a method of manufacturing sliders used in information recording disk drive units, and more particularly to a method of bonding slider row bars for photolithography process.

BACKGROUND OF THE INVENTION

One known type of information storage device is a disk drive device that uses magnetic media to store data and a movable read/write head that is positioned over the magnetic media to selectively read from or write to the rotating magnetic media, such as a magnetic disk.

FIG. 1aillustrates a conventional disk drive device200and shows a magnetic disk101mounted on a spindle motor102for spinning the disk101. A voice coil motor arm104carries a head gimbal assembly (HGA)100that includes a micro-actuator105and a slider103incorporating a read/write head. A voice-coil motor (VCM) is provided for controlling the motion of the motor arm104and, in turn, controlling the slider103to move from track to track across the surface of the disk101, thereby enabling the read/write head to read data from or write data to the disk101. In operation, a lift force is generated by the aerodynamic interaction between the slider103and the spinning magnetic disk101. The lift force is opposed by equal and opposite spring forces applied by a suspension of the HGA100such that a predetermined flying height above the surface of the spinning disk101is maintained over a full radial stroke of the motor arm104.

FIG. 1billustrates a perspective view of the slider shown inFIG. 1ain a bottom view. As illustrated, a magnetic reading/writing head116, which is used for realizing data reading/writing operation of the slider relative to the disk101, is formed on one side surface of the slider103. The slider103has an air bearing surface (ABS)117facing to the disk101. When the disk drive device is in operation, an aerodynamic interaction is generated between the ABS117of the slider103and the rotary disk101in a high speed, thus making the slider103floating over the disk101dynamically to perform data reading/writing operation.

To make the slider read data from or write data to the disk successfully, the slider is required to have a good flying stability, i.e. the flying height of slider is kept at an invariable value when the slider is flying over the disk. If the slider has a bad flying stability, the flying height is variable i.e. sometimes the flying height becomes higher and sometimes the flying height becomes lower. If the flying height is too high, the slider may not successfully realizing a read/write operation; if the flying height is too low, the slider may scratch the disk to cause a damage of the disk and/or the slider.

Understandably, manufacturing accuracy of the ABS of the slider is a key factor to influence the flying stability of the slider. Here, a process of forming the ABS of the slider is described briefly as follows. Generally, the ABS of the slider is formed by photolithography process and vacuum etching process in sequence. At first, a photo-resist coating is covered on an ABS-forming surface of the slider; then, an air bearing surface pattern (ABS pattern) are transferred to the photo-resist coating by exposure; next, the photo-resist coating is developed to get rid of unexposed portions of the photo-resist coating; and finally, portions of the ABS-forming surface uncovered by the photo-resist coating is etched by ion beam to form an ABS.

In related art, a manufacturing process of the slider is typically based on a plurality of slider row bars, each of which is constructed by a plurality of slider bodies. A slider row bar may comprise 30-100 slider bodies according to different product type. These slider row bars are encapsulated together by adhesive to form an entire row bar assembly. After being processed, these row bar assemblies are separated from each other and finally each of these row bar assemblies is cut into separate sliders.

FIGS. 2a-2bshow a slider row bar used for forming sliders. As shown in the figures, the slider row bar2has a width W and a thickness T. The slider row bar2has an ABS-forming surface3.FIG. 2cshows a carrier1for holding the slider row bars2. The conventional slider row bar bonding method is preformed as follows: firstly, as shown inFIG. 3, a kind of fast-curing glue5is dispensed on the carrier1by a glue dispenser6. Then, as shown inFIG. 4, a slider row bar2is moved toward the carrier1by a vacuum pickup head7and then adhered to the carrier1by the fast-curing glue5. Here, the slider row bar2has a slider-mounting surface4to contact the fast-curing glue5, which is opposite to the ABS-forming surface3. Next, as shown inFIG. 5, the above two steps are repeated until all the slider row bars2are attached on the carrier1, and then, the row bars are kept for 1-3 hours so that the glue5is cured completely so that all the slider row bars2are fixed on the carrier1. Then, as shown inFIG. 6, a kind of encapsulating glue9is dispensed in the gaps formed between the slider row bars2by a glue dispenser8. Finally, the encapsulating glue9is exposed to ultraviolet light and eventually cured to bond all the slider row bars2together to form a slider row bar assembly.

FIG. 7ashows a plurality of slider row bars2encapsulated together and bonded onto the carrier1.FIG. 7bshows a cross-sectional view ofFIG. 7ataken along line Z-Z. Referring toFIG. 7b, a plurality of glue recesses30are formed in a plurality of gaps (not labeled) between the slider row bars2. The glue recesses30are formed by natural shrinkage of the encapsulating glue9during curing process. Referring toFIG. 7aandFIG. 7b, the ABS-forming surfaces3of the slider row bars2and the glue recesses30form a base surface of the slider row bar assembly on which a photo-resist coating will be covered.

Also referring toFIG. 7b, it is easily to understand that the flatness of the base surface of the slider row bar assembly is mainly determined by two factors: the glue recesses30and thickness uniformity of the slider row bars2. First, as the slider row bars2have a small thickness, normally in a range of hundreds of microns, it is very difficult to improve thickness uniformity of the slider row bars2. On the other hand, the glue recesses30are unavoidable due to the inherent character of the encapsulating glue9. In the conventional slider row bar bonding process, because each of the slider row bars2and the glue5thereunder has a different thickness (i.e. the slider row bars2and the glue5thereunder has a thickness variation), and there are the glue recesses30, the flatness of the base surface of the slider row bar assembly is decreased seriously. Accordingly, a photo-resist coating formed on the base surface of the slider row bar assembly has a bad flatness.

In the photolithography process of forming the ABS of the slider, the flatness of the photo-resist coating has a big influence on manufacturing accuracy of the ABS of the slider. More concretely, if the flatness of the photo-resist coating covered on the ABS-forming surfaces is bad, the ABS patterns transferred to the photo-resist coating through exposure will have a distortion in shape relative to the predetermined ABS pattern. Accordingly, the ABS pattern formed on the slider row bars by etching process will not match the predetermined ABS pattern. This will make the slider with such a ABS pattern have a bad flying stability and thus make the disk drive has a bad flying performance and may has a fear that the disk and/or the slider may be damaged.

Thus, it is desired to provide a method for bonding slider row bars for photolithography process to overcome the above-mentioned drawbacks.

SUMMARY OF THE INVENTION

One object of the invention is to provide a method for bonding a plurality of slider row bars for photolithography process, which can greatly improve the flatness of ABS-forming surface of the bonded slider row bars.

Another object of the invention is to provide a method for manufacturing sliders, which can improve manufacturing accuracy of the sliders.

To achieve the above objects, a method for bonding slider row bars for photolithography process, comprises steps of: (1) forming a holding device having a sticky surface; (2) providing a plurality of slider row bars each of which has a first surface for forming ABS and a second surface opposite to the first surface, and securing the slider row bars on the holding device with their first surfaces facing to the sticky surface; (3) bonding the slider row bars together by an encapsulating glue; (4) providing a carrier and bonding the carrier to the second surfaces of the slider row bars; (5) removing the holding device.

In an embodiment, the step (1) comprises steps of: (a) providing a frame having an hole therein; (b) providing a film having a sticky layer serving as the sticky surface and a non-sticky layer laminated together, and covering the film on the frame with the sticky layer facing to the frame; (c) providing a vacuum transfer fixture having a base plate and a protrusion stage which is positioned on the base plate and has a plurality of vacuum holes defined therein; (d) assembling the vacuum transfer fixture to the frame with the protrusion stage received in the hole of the frame and contacting with the non-sticky layer of the film to form the holding device. In addition, the method may further comprise a step of evacuating spaces defined by the vacuum holes and non-sticky layer to generate air pressure to press the film against the protrusion stage after the step (1).

The step (3) may comprise steps of: (i) providing a glue-restraining plate having an opening and attaching the glue-restraining plate to the sticky layer of the film such that the slider row bars are exposed from the opening; (ii) dispensing the encapsulating glue into the opening of the glue-restraining plate; (iii) laminating the encapsulating glue dispensed in the opening of the glue-restraining plate such that the encapsulating glue flows into spaces defined between the slider row bars; (iv) curing the encapsulating glue such that all the slider row bars are bonded together.

The step (4) may comprise steps of: providing a kind of fast-curing glue and dispensing the fast-curing glue to the second surfaces of the slider row bars; and attaching the carrier to the second surfaces of the slider row bars via the fast-curing glue. Moreover, an elastic layer may be sandwiched between the carrier and the second surfaces of the slider row bars to absorb shrinkage stress generated by the fast-curing glue.

The step (5) may comprise steps of: (A) removing the vacuum transfer fixture from the frame; and (B) removing the film from the slider row bars.

The encapsulating glue may be any suitable adhesive, such as a kind of adhesive comprising cyanoacrylate.

A method for manufacturing sliders, comprises steps of: (1) forming a holding device having a sticky surface; (2) providing a plurality of slider row bars each of which has a first surface for forming ABS and a second surface opposite to the first surface, and securing the slider row bars on the holding device with their first surfaces facing to the sticky surface; (3) bonding the slider row bars together by an encapsulating glue; (4) providing a carrier and bonding the carrier to second surfaces of the slider row bars; (5) removing the holding device; (6) etching the first surfaces of the slider row bars; (7) cutting the slider row bars into separate sliders.

DETAILED DESCRIPTION OF THE INVENTION

Now, according to an embodiment of the invention, a method for bonding a plurality of slider row bars together for photolithography process is described. Referring toFIG. 8, the method comprises: forming a holding device having a sticky surface (step101); providing a plurality of slider row bars each of which has a first surface for forming ABS and a second surface opposite to the first surface, and securing the slider row bars on the holding device with their first surfaces facing to the sticky surface (step102); bonding the slider row bars together by an encapsulating glue to form a slider row bar assembly (step103); providing a carrier and bonding the carrier to the second surfaces of the slider row bars (step104); removing the holding device (step105).

Next, as shown inFIGS. 9c-9d, a vacuum transfer fixture13is provided. The vacuum transfer fixture13has a base plate132and a protrusion stage15extended from the base plate132. Corresponding to the screw holes11of the frame10, a plurality of screw holes14is formed on the perimeter of the base plate132. A plurality of vacuum holes16are formed in the protrusion stage15. The vacuum transfer fixture13is then assembled to the frame10with the protrusion stage15received in the hole31(refer toFIG. 9a) and covered by the non-sticky layer12a(refer toFIG. 9a) of the film12, thus forming a holding device300. The vacuum transfer fixture13may be assembled to the frame10using a plurality of bolts (not shown) which screwing in respective screw holes11and14. Finally, spaces defined between the vacuum holes16of the vacuum transfer fixture13and the film12are evacuated by suitable device, for example a pump, to generate air pressure to press the film12against the protrusion stage15.

FIGS. 10a-10cillustrate the step102of the method. As illustrated, a plurality of slider row bars18is attached to the holding device300. Each slider row bar18has a width W1and a thickness T1. In addition, each slider row bar18has a first surface19for forming an air bearing surface (ABS-forming surface, also refer toFIG. 13d) and a second surface182(slider-mounting surface) opposite to the first surface19. The first surface19is to be processed in a consequent manufacturing process such as a photolithography process so as to form an ABS pattern thereon. In this step, a vacuum pickup head17is repeatedly used to hold the slider row bar18and move it onto the sticky layer12bof the film12. Then, each slider row bar18is attached to the sticky layer12bwith its first surface19attached to the sticky layer12b.

FIGS. 11a-11dshow sequential views illustrating the step103of the method. Firstly, as shown inFIG. 11a, a glue-restraining plate21having an opening211is moved by a vacuum pickup head20and attached to the sticky layer12bof the film12, such that the slider row bars18held on the sticky layer12bare exposed from the opening211. Then, as shown inFIG. 11b, a kind of encapsulating glue23, such as cyanoacrylate, is dispensed into the opening211by a dispenser22. Next, as shown inFIGS. 11c-11d, the encapsulating glue23dispensed in the opening211is laminated such that it flows evenly into all spaces defined between the slider row bars18. The laminating process is performed via a laminator270. More specifically, the laminator270is constructed by a pair of roller27and a liner film28disposed between the two rollers27. Of course, the laminator270may has any other suitable structure to performing the above-identified function. When performing the laminating process, the liner film28is covered on the second surfaces182of the slider row bars18, while the two rollers27roll along the liner film28so that the encapsulating glue23is squeezed. Finally, the encapsulating glue23is cured such that all the slider row bars18are bonded together.

FIGS. 12a-12bshow sequential views illustrating the step104of the method. Firstly, as shown inFIG. 12a, a kind of fast-curing glue24is dispensed on the second surfaces182of the slider row bars18by a dispenser25. Then, as shown inFIG. 12b, a carrier26is moved by a vacuum pickup head27and attached to the second surfaces182of the slider row bars18via the fast-curing glue24, such that the entire slider row bars18are covered completely by the carrier26.

In addition, an elastic layer29(refer toFIG. 13d) may be sandwiched between the carrier26and the slider row bars18. When the fast-curing glue24shrinks due to its nature, a shrinkage stress will be generated. The shrinkage stress will cause the carrier26along with the slider row bars18held thereon to be deformed negatively. The elastic layer29helps reduce the deformation. In addition, the elastic layer29also functions as curing agent of the attaching glue24to facilitate the curing process. It is noted that though in the embodiment, an elastic film is used for absorbing the stress; however, this elastic film may be omitted in case that the stress is too weak to be accounted.

FIGS. 13a-13dshow sequential views illustrating the step105of the method. Firstly, as shown inFIG. 13a, the vacuum transfer fixture13is dismounted from the frame10to form a combination800. Preferably, before dismounting the vacuum transfer fixture13from the frame10, the air pressure applied on the film12against the protrusion stage15of the vacuum transfer fixture13(as described before) may be eliminated so as to make the dismounting process easier. Then, as shown inFIG. 13b, the combination800is turned upside down such that the non-sticky layer12aof the film12faces upward. Next, as shown inFIG. 13c, the non-sticky layer12aof the film12is peeled away from the sticky layer12b, and then the sticky layer12bis removed from the slider row bars18by suitable manner such as resolving method. By removal of the film12, an encapsulation combination900is formed.FIG. 13dshows a cross-sectional view of the encapsulation combination900ofFIG. 13calong line B-B. As illustrated, the slider row bars18are bonded each other by the encapsulating glue23to form a slider row bar assembly, which being restrained by the glue-restraining plate21. The carrier26and the elastic layer29are attached to the glue-restraining plate21by the fast-curing glue24. Notably, the first surfaces19of the slider row bars18are aligned each other perfectly and therefore has a high flatness.

FIG. 14shows surface scanning characteristics of the ABS-forming surface of the slider row bar assembly formed by the conventional method and method of the invention respectively. As illustrated, curve80, which represents surface scanning characteristics of the slider row bar assembly of the invention, is smoother greatly than curve81, which represents surface scanning characteristics of the slider row bar assembly of conventional method. In other word, utilizing the method of the invention can obtain a more ideal surface flatness of the slider row bar assembly than the conventional method.

FIG. 16shows a glue recess400formed on the ABS-forming surface of the slider row bars assembly, as illustrated, the depth presented with23R of the glue recess400is only 1 μm, while the depth presented with9R of the glue recess30in conventional method inFIG. 15are 20 μm. Namely, the slider row bar assembly has shallower glue recesses than that of the conventional method.

Compared with prior art, because it is the ABS-forming surface19of the slider row bars18, not the slider-mounting surfaces thereof are taken as a datum plane, an influence caused by thickness variation of the slider row bars is reduced, or even eliminated completely. In addition, since the ABS-forming surface19of the slider row bars18are pressed firmly on the protrusion stage15of the fixture13, glue shrinkage at the ABS-forming surfaces is baffled by the protrusion stage15, and thus glue recess happens mainly at the second surfaces (slider-mounting surfaces)182of the row bars; and therefore, influence caused by the glue recess400on the overall flatness of the ABS-forming surfaces is reduced greatly. That is to say, the flatness of the ABS-forming surface of the slider row bars assembly (the bonded slider row bars) is improved greatly so that the slider manufacturing by the method of the invention may have an excellent flying stability, and thus the disk drive has a good flying performance and there is no fear that the disk and/or the slider may be damaged.

Referring toFIG. 17, A method for manufacturing sliders, comprises steps of: forming a holding device having a sticky surface (step201); providing a plurality of slider row bars each of which has a first surface for forming air bearing surface and a second surface opposite to the first surface, and securing the slider row bars on the holding device with their first surfaces facing to the sticky surface (step202); bonding the slider row bars together by an encapsulating glue (step203); providing a carrier and bonding the carrier to second surfaces of the slider row bars (step204); removing the holding device (step205); etching the first surfaces of the slider row bars (step206); cutting the slider row bars into separate sliders (step207).