Abstract:
The method of the present invention is capable of processing a work piece with higher accuracy and providing highly reliable magnetic heads. The method of processing the magnetic head comprises the steps of: providing adhesive wax on a surface of a supporting jig; pressing a work piece onto the surface of the supporting jig so as to adhere the work piece thereon; heating the work piece supported by the supporting jig until the wax is melted so as to release stress in the work piece; and processing the work piece.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a method of processing a magnetic head, more precisely relates to a method of processing a magnetic head, in which a work piece, which has been cut from a wafer and formed into a bar-shaped piece, is supported by a supporting jig and processed, e.g., lapped.  
           [0002]    In the steps of manufacturing a magnetic head, MR-elements, etc. are formed in a wafer by forming film layers, etc., a plurality of bar-shaped pieces are formed by cutting the wafer, then sliders are made by processing, e.g., lapping, the bar-shaped pieces.  
           [0003]    The present invention relates to a method of processing a raw bar which is formed by cutting the wafer. Namely, the work piece, which has been formed into a bar-shaped piece by cutting the wafer, is horizontally supported on a supporting jig, then it is properly processed by a proper manner, e.g., ELG-lapping.  
           [0004]    In a conventional method, the work piece is pressed onto the supporting jig so as to adhere thereon with higher accuracy. However, stress in the work piece is released when the work piece is peeled from the supporting jig, so that the work piece is curved. Thus, in the following steps, the work piece is processed with monitoring height of the work piece, etc. Since the work piece is deformed in various directions, complex adjustment and treatment are required in the following steps, so that processing accuracy and processing efficiency are made lower.  
           [0005]    In the conventional method, undulation of submicron is formed in the work piece by flatness of the jig, dusts in wax, and roughness of a surface of the work piece. These days, in film-layered magnetic heads, general allowance is ±0.5 μm, so errors caused by adhering the work piece cannot be ignored.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention has been studied to solve the above described problems of the conventional method.  
           [0007]    An object of the present invention is to provide a method of processing a magnetic head, which is capable of restricting deformation of the work piece, easily processing the work piece in following steps and improving the processing accuracy.  
           [0008]    To achieve the object, the method of the present invention comprises the steps of: providing adhesive wax on a surface of a supporting jig; pressing a work piece onto the surface of the supporting jig so as to adhere the work piece thereon; heating the work piece supported by the supporting jig until the wax is melted so as to release stress in the work piece; and processing the work piece.  
           [0009]    In the method, a plurality of elements may be serially arranged in the work piece in the longitudinal direction thereof, and a center part of the arranged line of the elements may be located nearest to the surface of the supporting jig when the work piece supported by the supportingjig is heated.  
           [0010]    In the method, a plurality of elements may be serially arranged in the work piece in the longitudinal direction thereof, the arranged line of the elements, which is viewed from a side of the work piece, may be formed into a parabola line when the work piece supported by the supporting jig is heated, and the surface of the supporting jig may be deformed according to the arranged line.  
           [0011]    By employing the method of the present invention, the work piece can be processed with higher processing accuracy, undulation of the work piece can be corrected. Therefore, the magnetic heads, which request the allowance of submicron order, can be processed with higher accuracy, and the reliable magnetic heads can be produced. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    Embodiments of the present invention will now be described by way of examples and with reference to the accompanying drawings, in which:  
         [0013]    FIGS.  1 A- 1 C are explanation views showing the steps of adhering a work piece onto a supporting jig;  
         [0014]    FIGS.  2 A- 2 D are explanation views showing the steps of processing the work piece;  
         [0015]    [0015]FIGS. 3A and 3B are explanation views showing arrangement of elements in the work piece;  
         [0016]    [0016]FIG. 4 is an explanation view showing the work piece, which has been lapped;  
         [0017]    FIGS.  5 A- 5 C are explanation views respectively showing states of adhering the work piece onto the supporting jig; and  
         [0018]    FIGS.  6 A- 6 C are explanation views showing the steps of the conventional method of processing the work piece. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.  
         [0020]    FIGS.  1 A- 1 C show the steps of adhering a work piece  10  onto a supporting jig  20 .  
         [0021]    The work piece (raw bar)  10  is adhered onto a surface of the supporting jig  20  by wax  22 , which has been provided on the surface thereof. To adhere the work piece  10 , the supporting jig has been previously heated until reaching melting point of the wax  22 , then the wax  22  is waxed on the surface thereof, and the work piece  10  is mounted on the supporting jig  20 . Preferably, the work piece  10  is also previously heated.  
         [0022]    Next, the work piece  10  is pressed, by a pressing jig  24 , and cooled so as to precisely adhere the work piece  10 . With this manner, the work piece  10  can be adhered according to roughness of the surface of the supporting jig  20 .  
         [0023]    A shock absorbing member  26 , e.g., rubber, plastic, is adhered on a pressing face of the pressing jig  24 , so that the work piece  10  is pressed onto the supporting jig  20  by the shock absorbing member  26 . By providing the shock absorbing member  26 , uneven thickness of the work piece  10  can be absorbed, so that the work piece  10  can be securely adhered.  
         [0024]    In FIG. 1C, the work piece  10  is adhered on the supporting jig  20 . The work piece  10  is adhered according to roughness of the surface of the supporting jig  20 . If flatness of the supporting jig  20  is low or a dust  28  is included in the wax  22 , their shapes are transferred onto a surface of the work piece  10  adhered.  
         [0025]    After the work piece  10  is adhered on the supporting jig  20 , a lapping step is executed. The steps of adhering the work piece  10  on the supporting jig  20  are executed in the method of the present invention as well as the conventional method.  
         [0026]    The conventional method will be explained with reference to FIGS.  6 A- 6 C. In the conventional method, the lapping step (see FIG. 6A)) is executed after the work piece  10  is adhered to the supporting jig  20 . In FIG. 6B, a surface of the work piece  10  has been lapped. In FIG. 6C, the work piece  10  is curved after the lapping step is completed and the work piece  10  is peeled from the supporting jig  20 . Stress in the lapped surface of the work piece  10  is released by lapping work; stress in the adhered surface of the work piece  10  is released by peeling the work piece  10  from the supporting jig  20 . With this mechanism, the work piece  10  is curved. In the conventional method, following processing steps will be executed with monitoring or sensing the deformation of the work piece  10  as described before.  
         [0027]    The method of the present embodiment will be explained with reference to FIGS.  2 A- 2 D. The characteristic point of the present embodiment is that the work piece  10 , which has been adhered on the supporting jig  20 , is reheated and then processed. Namely, the work piece  10  adhered on the supporting jig  20  is reheated and then following process, e.g., lapping, is executed. An object of reheating the work piece  10  is to melt the wax  22  and to relieve the concentrated stress in the work piece  10 .  
         [0028]    The wax  22  is liquefied and the stress in the work piece  10  is relieved by the reheating step, then the work piece  10  is adhered onto the supporting jig  20 . The work piece  10 , etc. are naturally cooled without pressing the work piece  10  (see FIG. 2A)).  
         [0029]    [0029]FIG. 2B shows a state of lapping the work piece  10 , which has been adhered on the supporting jig  20 . FIG. 2C shows a state of completing the lapping step in which the surface of the work piece  10  has been evenly lapped.  
         [0030]    [0030]FIG. 2D shows a state in which the work piece has been peeled from the supporting jig  20  after completing the lapping step. In the present embodiment, the work piece  10  is reheated to relieve the stress therein, so that the work piece  10  can be peeled from the supporting jig  20  without greatly curving or deforming the work piece  10 .  
         [0031]    The work piece  10 , which is adhered on the supporting jig  20  and lapped, and elements (patterns)  30 , which are formed in the work piece  10  and serially arranged in the longitudinal direction of the work piece  10 , are shown in FIGS. 3A and 3B.  
         [0032]    In the conventional method, when the work piece  10  is adhered, the uneven surface of the jig, dusts in the wax, etc. are transferred thereto, so the elements  30  in the work piece  10  are complexly shifted in the vertical direction as shown in FIG. 3A. On the other hand, in the present embodiment, the work piece  10  is reheated, so that the arranged line of the elements  30 , which is viewed from a side of the work piece  10 , is adjusted and formed into a smooth parabola line (see a dotted line in FIG. 3B)).  
         [0033]    When the work piece  10  is lapped, the jig or jigs can be slightly deformed so as to process the work piece  10  along the arranged line of the elements  30 . But the jigs cannot be greatly deformed, so the arranged line should be a smoothly curved line. In the present embodiment, the work piece  10  is reheated, so that the arranged line of the elements  30  is formed into the parabola line and a processing track can be corresponded with the parabola line by deforming the jig or jigs with higher processing accuracy.  
         [0034]    These days, the processing accuracy of submicron is required when the film layered magnetic heads are processed. To improve the processing accuracy, it is important to restrict positional difference, in the vertical direction, among the elements  30  in the work piece, and it is also important to adjust the arranged line of the elements  30  to correspond with the smoothly curved line even if the elements  30  are mutually shifted in the vertical direction.  
         [0035]    In the case of lapping the work piece  10  with the supporting jig  20 , edges of the work piece  10  are apt to be overprocessed as shown in FIG. 4. In a lapping machine, outer parts or edges of the work piece  10  are ground more than a center part thereof is done and a center part of the jig is pushed and slightly indented, so that the overprocessed parts are formed. More preferably, the work piece  10  is adhered with considering estimated amount of the overprocess.  
         [0036]    As to the relationship among the shape of the surface of the supporting jig  20 , thickness of the wax and degree of parallel between the arranged line of the elements  30  and a cut end face of the work piece  10 , there are three cases of adhering the work piece  10  on the supporting jig  20  as shown in FIGS.  5 A- 5 C.  
         [0037]    In FIG. 5A, the work piece  10  is adhered on the supporting jig  20 , and a center part of the arranged line of the elements  30 , which is extended in the longitudinal direction of the work piece  10 , is located nearest to the surface of the supporting jig  20 . Namely, the center part of the arranged line is curved and projected toward the supporting jig  20 . In FIG. 5B, the work piece  10  is adhered on the supporting jig  20 , and the arranged line of the elements  30  is approximately parallel to the surface of the supporting jig  20 . In FIG. 5C, the work piece  10  is adhered on the supporting jig  20 , and a center part of the arranged line of the elements  30 , which is extended in the longitudinal direction of the work piece  10 , is located farthest from the surface of the supporting jig  20 . Namely, the center part of the arranged line is curved and projected upwardly.  
         [0038]    In the cases shown in FIGS. 5A and 5B, the center part of the jig is pushed or pressed with considering the estimated amount of overprocessing the edges of the work piece  10 . Namely, in the cases that the arranged lines of the elements  30  are the smoothly curved lines as shown in FIGS. 5A and 5B, precise processing can be executed by adjusting the deformation of the jig.  
         [0039]    In the case shown in FIG. 5C, if amount of shifting the elements  30  is greater than that of overprocessing the edges of the work piece  10 , the deformation of the jig should be adjusted in the reverse direction. If the work piece  10  is reheated and adhered on the supporting jig  20 , the arranged line of the elements  30  which is upwardly curved is made more smooth, so that degree of the reverse deformation of the jig can be reduced.  
         [0040]    As described above, in the present invention, the work piece can be processed on the supporting jig with higher processing accuracy, the undulation of the work piece can be corrected. Therefore, the magnetic heads, which request the allowance of submicron order, can be processed properly.  
         [0041]    The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.