What is claimed is:
1. A method of making a thin film magnetic head, comprising:
forming a lower magnetic core layer;
forming a non-magnetic gap layer;
forming an upper magnetic pole piece on the non-magnetic gap layer;
forming a non-magnetic cap layer on the upper magnetic pole piece;
forming a non-magnetic insulating layer covering over the non-magnetic cap layer and the upper magnetic pole piece;
flattening the non-magnetic insulating layer so as to expose the non-magnetic cap layer;
removing the non-magnetic cap layer so as to expose the upper magnetic pole piece; and
forming an upper magnetic core layer covering over the upper magnetic pole piece.
2. The method of making according to claim 1, further comprising: forming a lower magnetic pole piece on an upper surface of the lower magnetic core layer under the non-magnetic gap layer.
3. The method of making according to claim 2, further comprising:
sequentially forming the non-magnetic gap layer, the upper magnetic pole piece and the non-magnetic cap layer on the upper surface of the lower magnetic core layer; and
patterning a contour of the lower magnetic pole piece with the upper magnetic pole piece and the non-magnetic cap layer in forming the lower magnetic pole piece.
4. The method of making according to claim 3, wherein said non-magnetic cap layer is made from a material having an etching ratio different from that of the non-magnetic insulating layer.
5. The method of making according to claim 4, wherein said non-magnetic cap layer is made from SiO2, while said non-magnetic insulating layer is made from Al2O3.
6. The method of making according to claim 4, wherein said non-magnetic cap layer is made from Al2O3, while said non-magnetic insulating layer is made from SiO2.
7. The method of making according to claim 4, wherein said non-magnetic cap layer is a non-magnetic metallic layer, while said non-magnetic insulating layer is an oxide insulating layer.
8. The method of making according to claim 3, wherein said non-magnetic cap layer is made from a material having an etching ratio different from that of the non-magnetic gap layer.
9. The method of making according to claim 8, wherein said non-magnetic cap layer is made from SiO2, while said non-magnetic gap layer is made from Al2O3.
10. The method of making according to claim 8, wherein said non-magnetic cap layer is made from Al2O3, while said non-magnetic gap layer is made from SiO2.
11. The method of making according to claim 8, wherein said non-magnetic cap layer is a non-magnetic metallic layer, while said non-magnetic gap layer is an oxide insulating layer.
12. A thin film head comprising:
a lower magnetic core layer;
a non-magnetic gap layer overlying over the lower magnetic core layer;
an upper magnetic pole piece formed on the non-magnetic gap layer;
a non-magnetic insulating layer surrounding the upper magnetic pole piece so as to define a depression on an upper surface of the upper magnetic pole piece; and
an upper magnetic core layer connected to the upper magnetic pole piece.
13. The thin film head according to claim 12, further comprising a lower magnetic pole piece swelling from an upper surface of the lower magnetic core layer.
14. The thin film head according to claim 13, wherein said lower magnetic pole piece, the non-magnetic gap layer and the upper magnetic pole piece are patterned in an identical contour.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A stencil for applying a paste to a wafer comprising:
a stencil, comprised of plastic, having a top surface, a bottom surface, a thickness, and a plurality of apertures passing from said top surface to said bottom surface, at least one aperture of said plurality of apertures, including:
a first portion of said at least one aperture formed by a first wall portion extending generally vertically from said top surface of said stencil into said at least one aperture of said plurality of apertures and having a first diameter forming a first cross-sectional area;
a second portion of the at least one aperture of the plurality of apertures formed by a second wall portion extending generally vertically from said bottom surface of said stencil into said at least one aperture of said plurality of apertures and having a second diameter forming a second cross-sectional area;
at least one sloped annular shoulder intermediate said first wall portion and said second wall portion of said at least one aperture of said plurality of apertures, said at least one sloped annular shoulder having a shape, the shape including a sloped shape extending in a direction; and
said second cross-sectional area in said at least one aperture of said plurality of apertures larger than said first cross-sectional area of said first portion of said at least one aperture of said plurality of apertures for providing a location of said second wall portion of said at least one aperture of said plurality of apertures free of contact by said paste during use of said stencil, said thickness of said stencil ranging from about 0.1 to 10 times the first diameter of said at least one aperture of said plurality of apertures adjacent said top surface of said stencil.
2. The stencil according to claim 1, wherein said shape of said at least one sloped annular shoulder of said at least one aperture of said plurality of apertures comprises said sloped annular shoulder sloped towards said bottom surface of said stencil.
3. A method for forming substantially vertical elements of paste on an object having a surface comprising:
providing a stencil having a plurality of apertures formed therethrough from a top surface of said stencil to a bottom surface of said stencil, at least one aperture of said plurality of apertures including a first portion having a first cross-sectional area formed by a first wall portion having a first diameter and extending generally vertically from said top surface of said stencil, a second portion of said at least one aperture of said plurality of apertures adjacent said bottom surface of said stencil and having a second cross-sectional area formed by a second wall portion having a second diameter larger than said first nominal diameter of said first wall portion and extending generally vertically from said bottom surface of said stencil, said stencil having a thickness in the range from 0.1 to 10 times the first diameter of the first wall portion of said at least one aperture of said plurality of apertures, and at least one sloped annular shoulder having a shape located between said first wall portion and said second wall portion of said at least one aperture of said plurality of apertures;
applying said stencil to a surface of said object;
extruding said paste, said paste having a viscosity in the range between 30K to 310K centipoise through said plurality of apertures formed in said stencil;
wiping said paste across said top surface of said stencil to force said paste through said plurality of apertures;
preventing contact of said paste with a portion of said second wall portion of said at least one aperture of said plurality of apertures during said extruding of said paste by said second cross-sectional area of said second portion of said at least one aperture of said plurality of apertures being larger than said first cross-sectional area of said first portion of said at least one aperture of said plurality of apertures; and
removing said stencil and leaving portions of said solder paste in a substantially vertical column.
4. The method according to claim 3, wherein said extruding further comprises:
applying said paste to said top surface.
5. The method according to claim 3, wherein said paste has a viscosity of approximately 70K centipoise.
6. The method according to claim 3, wherein said paste has a thixotropic index ranging between about 1.7 to 3.2.
7. The method according to claim 3, wherein said paste has a thixotropic index of approximately 2.5.
8. The method according to claim 3, wherein said stencil is made of stainless steel.
9. The method according to claim 3, wherein said stencil is made of plastic.
10. The stencil according to claim 1, wherein said at least one sloped annular shoulder slopes from said first portion of said at least one aperture of said plurality of apertures towards said second portion of said at least one aperture of said plurality of apertures.
11. The stencil according to claim 10, wherein said at least one sloped annular shoulder has an acute shape.
12. The stencil according to claim 10, wherein said at least one sloped annular shoulder has an obtuse shape.
13. The stencil according to claim 10, wherein said at least one sloped annular shoulder has an indented shape.
14. The method according to claim 3, wherein said at least one sloped annular shoulder slopes from said first portion of said at least one aperture of said plurality of apertures towards said second portion of said at least one aperture of said plurality of apertures.
15. The method according to claim 14, wherein said at least one sloped annular shoulder has an acute shape.
16. The method according to claim 14, wherein said at least one sloped annular shoulder has an obtuse shape.
17. The method according to claim 14, wherein said at least one sloped annular shoulder has an indented shape.