U.S. patent application number 09/819633 was filed with the patent office on 2001-11-01 for plating method and apparatus, and manufacturing method of thin film magnetic head using the same.
This patent application is currently assigned to TDK CORPORATION. Invention is credited to Kamijima, Akifumi.
Application Number | 20010035355 09/819633 |
Document ID | / |
Family ID | 18640278 |
Filed Date | 2001-11-01 |
United States Patent
Application |
20010035355 |
Kind Code |
A1 |
Kamijima, Akifumi |
November 1, 2001 |
Plating method and apparatus, and manufacturing method of thin film
magnetic head using the same
Abstract
The invention relates to a frame plating method for forming a
plating film using a mold formed by patterning a resist, and has an
object to provide the frame plating method in which tilting of a
resist frame having a high aspect ratio is easily and certainly
prevented and a desired plating film can be formed. The
constitution includes a developing/washing portion 100 for
developing an exposed resist layer formed on a substrate 138 and
for washing a developing solution by a washing solution, and a
plating portion 50 for immersing a surface of the substrate 138 in
a state where the washing solution is not dried after washing but
is held, into a plating solution 62 to carry out plating.
Inventors: |
Kamijima, Akifumi; (Tokyo,
JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
277 S. WASHINGTON STREET, SUITE 500
ALEXANDRIA
VA
22314
US
|
Assignee: |
TDK CORPORATION
|
Family ID: |
18640278 |
Appl. No.: |
09/819633 |
Filed: |
March 29, 2001 |
Current U.S.
Class: |
205/118 ;
204/202; 204/242; 257/E21.026; G9B/5.094 |
Current CPC
Class: |
C25D 7/123 20130101;
C25D 5/022 20130101; H01L 21/0273 20130101; G11B 5/3163
20130101 |
Class at
Publication: |
205/118 ;
204/242; 204/202 |
International
Class: |
C25D 005/02; C25D
017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 28, 2000 |
JP |
2000-131368 |
Claims
What is claimed is:
1. A plating method, comprising the steps of: forming an electrode
film on a substrate; forming a resist layer on the electrode film;
developing the resist layer after exposure through a predetermined
mask; washing a developing solution on a surface of a resist frame
formed through development by a washing solution; and after
washing, immersing a surface of the substrate in a state where the
washing solution is held without being dried, into a plating
solution to carry out plating.
2. A plating apparatus, comprising: a developing/washing port ion
for developing an exposed resist layer formed on a substrate and
for washing a developing solution by a washing solution; and a
plating portion for carrying out plating after washing by immersing
a surface of the substrate in a state where the washing solution is
held without being dried, into a plating solution.
3. A plating apparatus according to claim 2, wherein the plating
portion includes an opening portion to be closed by the
substrate.
4. A plating apparatus according to claim 3, wherein the
developing/washing portion includes a transporting mechanism for
transporting the substrate to the opening portion.
5. A plating apparatus according to claim 2, further comprising a
drainage receiving portion for receiving plating drainage between
the developing/washing portion and the plating portion.
6. A manufacturing method of a thin film magnetic head, comprising
a plating process of forming a plating film using a mold formed by
patterning a resist, wherein the plating process comprises a
plating method according to claim 1.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a plating method
(hereinafter referred to as a frame plating method) for forming a
plating film by using a mold formed by patterning a resist, a
plating apparatus used in the frame plating method, and a
manufacturing method of a thin film magnetic head provided with an
induction type magnetic head as a recording head.
[0003] 2. Description of the Related Art
[0004] A composite type thin film magnetic head including a
magnetoresistive (MR) head used for data reproduction and an
induction type magnetic head used for data recording is used as a
magnetic head of a magnetic disk device.
[0005] The MR head includes any one of an AMR (Anisotropic
Magnetoresistive) component using an AMR effect, a GMR (Giant
Magnetoresistive) component using a GMR effect, and a TMR
(Tunneling Magnetoresistive) component using a tunnel junction film
indicating a magnetoresistive effect. As surface recording density
of a magnetic recording medium becomes high, a component to be used
is changed from the AMR component to the GMR component, and
further, to the TMR component.
[0006] As one factor for determining the performance of the MR
heads, there is optimization of MR height. The MR height is a
height of the MR component from an end portion at a side of an air
bearing surface (ABS) opposite to a magnetic recording surface of a
magnetic recording medium to an end portion at the opposite side,
and this height depends on an amount of polishing of the ABS
surface in a head manufacturing process.
[0007] The induction type magnetic head realizes a ring structure
having a narrow gap by a semiconductor process, and includes upper
and lower magnetic poles which are laminated through an insulating
film and has a gap (write gap) at the side of the ABS surface to
form a closed magnetic path, and a thin film coil formed in the
insulating film between the upper and lower magnetic poles. The
head material is magnetized to high magnetic flux density by
recording current flowing through the thin film coil, and
predetermined leakage magnetic field is formed over the gap to
record data.
[0008] As one factor for determining the performance of the
induction type magnetic head, there is optimization of throat
height (TH). The throat height is a height of the magnetic pole
from the ABS surface to the end portion of the insulating film, and
this height also depends on an amount of polishing of the ABS
surface in the head manufacturing process. In order to improve the
head efficiency of the recording head, it is necessary to make the
throat height as small as possible.
[0009] In order to raise the recording density, it is necessary to
raise the track density of the magnetic recording medium. For that
purpose, it is necessary to realize a recording head in which
magnetic pole width and gap width at the ABS surface are made
narrow, and a semiconductor processing technique is used for
realizing this.
[0010] The foregoing composite type thin film magnetic head is
manufactured through a plurality of manufacturing processes, for
example, a sputtering process, a photolithography process, a frame
plating process, an etching process, a polishing process, and the
like. Hereinafter, an example of a manufacturing method of the thin
film magnetic head will be described in brief.
[0011] First, an Al.sub.2O.sub.3TiC substrate having high hardness
and excellent in wear resistance is used. When the magnetic head is
completed, this substrate itself functions as a slider body of the
magnetic head. The reason why the substrate having high hardness
and excellent in wear resistance is used is to secure floating
accuracy of the head and to obtain accurate MR height and throat
height.
[0012] A film having high adhesiveness, for example, a chromium
film is formed on the Al.sub.2O.sub.3TiC substrate by sputtering or
the like. Next, a lower shield layer made of, for example,
permalloy is formed. Next, an MR component interposed between
insulating films is formed on the lower shield layer.
[0013] Next, an upper shield layer made of, for example, permalloy
is formed. By this, an MR head for reproduction is completed. The
upper shield layer is also used as a lower magnetic pole of an
induction type magnetic head for recording.
[0014] Next, an insulating film for formation of a gap is formed on
the lower magnetic pole, and further, an insulating film is formed,
and then, a film excellent in adhesiveness to an oxide, for
example, a chromium film is formed thereon by sputtering or the
like. Next, there is formed a thin film of, for example, copper,
which becomes an electrode film when a frame plating method is
used. Next, a copper coil of a first layer is formed by the frame
plating method. As the need arises, coils of second to third layers
are also formed in the same way.
[0015] After the formed thin film coil is embedded by an insulating
film, an upper magnetic pole made of, for example, permalloy is
formed thereon by using the frame plating method. A recording gap
layer is formed by carrying out etching while the upper magnetic
pole at the side of the ABS surface is used as a mask. The upper
magnetic pole is formed so that it is connected to the lower
magnetic pole through the coil at the opposite side of the
recording gap layer so as to constitute a closed magnetic path. A
protective film is formed on an upper layer of the upper magnetic
pole, and the film forming process is completed.
[0016] Next, the Al.sub.2O.sub.3TiC substrate is cut into rod-like
substrates including several tens heads. The ABS formation surface
of the rod-like substrate is polished to provide the throat height
of a height of several pm. After the ABS surface is formed, the
rod-like substrate is cut, so that a plurality of thin film
magnetic heads are completed. In the manufacturing method of the
thin film magnetic head as described above, the frame plating
method is used for the formation of the thin film coil or the
formation of the upper magnetic pole.
[0017] A conventional frame plating method will be described in
brief with reference to FIGS. 8A to 8E and FIG. 9. The frame
plating method is a method of patterning a plating film by using a
mold formed by patterning a resist, as disclosed in, for example,
Japanese Patent Publication No. S56-36706.
[0018] FIGS. 8A to 8E are sectional views showing a manufacturing
process of a plating film using the conventional frame plating
method. As shown in FIG. 8A, an electrode film 502 is formed on an
insulating substrate 500 by using a sputtering method or an
evaporation method. As a lower layer of the electrode film 502, an
adhesive layer, for example, a Cr (chromium) film or a Ti
(titanium) film, may be formed to raise the adhesiveness to the
insulating substrate 500. Although there is no problem when the
electrode film 502 is made of a material having conductivity, if
possible, it is desirable to use the same material as a metal
material to be plated.
[0019] Next, as shown in FIG. 8B, a resist is coated on the whole
surface to form a resist layer 504, and as the need arises, a
pre-bake treatment of the resist layer 504 is performed. Next,
exposure light is irradiated through a mask 506 on which a
predetermined pattern is drawn, so that the resist layer 504 is
exposed.
[0020] Next, after a heat treatment is performed as the need
arises, development is carried out by an alkaline developing
solution. As the alkaline developing solution, for example,
tetramethylammonium hydroxide (TMAH) of a concentration of 2.38 wt
% is used. Next, the developing process successively shifts to a
washing process. The developing solution in the resist layer 504 is
washed by a washing solution 510, and a development dissolving
reaction in the resist layer 504 is stopped, so that as shown in
FIG. 8C, resist frames 508 patterned into a predetermined shape are
formed. As the washing solution, for example, pure water is
used.
[0021] When washing is ended, the washing solution 510 is blown
away and is dried. If necessary, the substrate 500 may be heated to
dry the washing solution (see FIG. 8D).
[0022] Next, the substrate 500 is immersed in a plating solution
512 in a plating bath, and a plating process is carried out using
the resist frames 508 as a mold, so that plating films 514 are
formed between the resist frames 508 (see FIG. 8E). Next, as the
need arises, water washing and drying are carried out, and then,
the resist frames 508 are peeled off from the substrate 500 by
using an organic solvent. Next, the electrode film 502 is removed
by dry etching (ion milling, reactive ion etching (RIE), etc.) or
wet etching while the plating films 514 are used as a mask. The
above is an outline of the frame plating method.
[0023] Like this, although the frame plating method is a technique
for forming the plating films 514 of a predetermined shape using
the resist frames 508 obtained by patterning the resist layer 504
as the mask, there is a problem that such a phenomenon occurs that
in the washing step when the resist frames 508 are formed, the
resist frames 508 on the substrate 500 tilt as shown in FIG. 9.
[0024] For example, when the upper magnetic pole of the thin film
magnetic head is formed by the frame plating method, since
undulations having a relatively large difference in height are
produced in a coating region of the resist layer 504, a locally
very thick resist layer 504 is formed. Since a pattern of a
relatively very thin line width is formed in the thick resist layer
504, the resist frame 508 having a high aspect ratio is formed.
[0025] When the resist frame 508 having such a high aspect ratio is
formed, after the developing solution is washed, the substrate 500
is rotated to blow away the washing solution 510 adhered to the
substrate, so that drying shown in FIG. 8D is carried out. At the
time of this drying, surface tension of the washing solution 510,
centrifugal force resulting from the rotation of the substrate, and
pressing force from the washing solution are applied to the resist
frame 508. It appears that the resist frame 508 is tilted by these
forces at the time of drying. Incidentally, in addition to the
tilting, there is also a case where bending, breaking or peeling of
the pattern occurs.
[0026] This phenomenon becomes remarkable as the width of the
resist frame becomes narrow, the interval becomes narrow, and the
aspect ratio of the section of the resist pattern becomes
large.
[0027] As a method of preventing such tilting of the resist frame,
document 1 (Handbook of Resist Material for Semiconductor
Integrated Circuit, Realize Corp. 1996, pp. 218-220) discloses a
low surface tension rinse and a freeze drying method as surface
tension action reducing methods, and discloses a high strength
(high rigidity) resist and a resist hardening method in a rinse
liquid as resist strength improving methods. The low surface
tension rinse uses a tertiary butyl alcohol solution is used as a
washing solution, and the surface tension of the washing solution
operating on the resist pattern is lowered to prevent the tilting.
In the freeze drying method, a washing solution after washing is
frozen and is sublimated, so that drying is made in the state where
the surface tension is hardly produced. The high intensity resist
prevents the tilting by using a material which can withstand the
various forces operating on the resist pattern. In the resist
hardening method in the rinse liquid, a photo-crosslinking type
resist or thermo-crosslinking type resist is used for the resist
layer, and light irradiation or heating is performed in the washing
solution to increase the strength of the resist layer, so that the
tilting is prevented.
[0028] Japanese Patent Publication No. H06-105684 discloses a
technique for carrying out drying in a state where a washing
solution is made to have a critical state and the surface tension
is made 0 (zero), similarly to the above surface tension reducing
method. Japanese Patent No. 2762226 discloses a method in which a
pressure in a sealed container is reduced to a pressure slightly
smaller than a saturation vapor pressure, and the washing solution
is gradually evaporated to be dried.
[0029] However, in the above surface tension reducing method and
its similar technique, there easily occurs such a problem that the
washing solution remains on the surface of the substrate after
drying to produce a stain or the like, and plating abnormality
occurs in a subsequent plating step. Besides, if the surface
tension is low, a possibility that the washing solution intrudes
into an interface between the resist layer and the substrate to
cause pattern peeling, becomes high.
[0030] On the other hand, in the resist strength improving method,
in view of reduction in cost and reduction in the number of steps,
there is no satisfactory resist material under the preset
circumstances.
SUMMARY OF THE INVENTION
[0031] An object of the present invention is to provide a frame
plating method in which tilting of a resist frame having a high
aspect ratio is easily and certainly prevented, and a desired
plating film can be formed.
[0032] Another object of the present invention is to provide a
plating apparatus which is suitably used in a frame plating method
in which tilting of a resist frame having a high aspect ratio is
easily and certainly prevented, and a desired plating film can be
formed.
[0033] Still another object of the present invention is to provide
a manufacturing method of a thin film magnetic head using a frame
plating method in which tilting of a resist frame having a high
aspect ratio is easily and certainly prevented, and a desired
plating film can be formed.
[0034] The above object is achieved by a plating method
characterized in that an electrode film is formed on a substrate, a
resist layer is formed on the electrode film, the resist layer is
developed after exposure through a predetermined mask, a developing
solution on a surface of a resist frame formed by development is
washed by a washing solution, and after washing, a surface of the
substrate in a state where the washing solution is held without
being dried, is immersed into a plating solution to carry out
plating.
[0035] Besides, the above object is achieved by a plating apparatus
characterized by comprising a developing/washing portion for
developing an exposed resist layer formed on a substrate and for
washing a developing solution by a washing solution, and a plating
portion for carrying out plating after washing by immersing a
surface of the substrate in a state where the washing solution is
held without being dried, into a plating solution.
[0036] The plating apparatus is characterized in that the plating
portion includes an opening portion to be closed by the substrate.
Besides, the plating apparatus is characterized in that the
developing/washing portion includes a transporting mechanism for
transporting the substrate to the opening portion.
[0037] Further, the plating apparatus is characterized by
comprising a drainage receiving portion for receiving plating
drainage between the developing/washing portion and the plating
portion.
[0038] Further, the above object is achieved by a manufacturing
method of a thin film magnetic head, which comprises a plating
process of forming a plating film using a mold formed by patterning
a resist and is characterized in that the plating process comprises
the plating method of the present invention.
[0039] According to the present invention, in the development step
at the time of forming the resist frame, the surface of the
substrate is immersed into the plating solution to carry out
plating, while the washing solution on the surface of the substrate
after washing of the developing solution is not blown away and the
layer of the washing solution is held. Accordingly, even if the
resist pattern has a high aspect ratio, it can be easily and
certainly formed without causing tilting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] FIGS. 1A to 1D are process sectional views showing a frame
plating method according to a first embodiment of the present
invention;
[0041] FIGS. 2A to 2D are process sectional views showing the frame
plating method according to the first embodiment of the present
invention;
[0042] FIG. 3 is a schematic view showing an outline structure of a
frame plating apparatus according to a second embodiment;
[0043] FIGS. 4A to 4H are process sectional views showing a
manufacturing method of a thin film magnetic head using a frame
plating method according to a third embodiment of the present
invention;
[0044] FIGS. 5A to 5D are process sectional views showing the frame
plating method in the manufacturing method of the thin film
magnetic head according to the third embodiment of the present
invention;
[0045] FIGS. 6A to 6C are process sectional views showing the frame
plating method in the manufacturing method of the thin film
magnetic head according to the third embodiment of the present
invention;
[0046] FIGS. 7A to 7C are process sectional views showing the frame
plating method in the manufacturing method of the thin film
magnetic head according to the third embodiment of the present
invention;
[0047] FIGS. 8A to 8E are sectional views showing a manufacturing
process of a plating film using a conventional frame plating
method; and
[0048] FIG. 9 is a view showing tilting of a resist frame in the
conventional frame plating method.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0049] A frame plating method according to a first embodiment of
the present invention will be described with reference to FIGS. 1A
to 1D and FIGS. 2A to 2D. FIGS. 1A to 2D are sectional views
showing a manufacturing process of a plating film using the frame
plating method. First, as shown in FIG. 1A, an electrode film 2 is
formed on an insulating substrate 1 by using a sputtering method or
an evaporation method. An adhesive layer for improving adhesiveness
to the insulating substrate 1 may be formed under the electrode
film 2 by, for example, a Cr (chromium) film or a Ti (titanium)
film. Although there is no problem as long as the conductive film 2
is made of a material having conductivity, if possible, it is
desirable to use the same material as a metal material to be
plated.
[0050] Next, as shown in FIG. 1B, a resist is coated on the whole
surface to form a resist layer 3, and a pre-bake treatment is
carried out as the need arises. Next, exposure light is irradiated
through a mask 4 on which a predetermined pattern is drawn, so that
the resist layer 3 is exposed.
[0051] Next, after a heat treatment is carried out as the need
arises, as shown in FIG. 1C, the exposed resist layer 3 is
developed by an alkaline developing solution 5 to form resist
frames 6. As the alkaline developing solution 5, for example,
tetramethylammonium hydroxide (TMAH) of a concentration of 2.38 wt
% can be used.
[0052] Next, the development process successively shifts to a
washing process. The developing solution 5 on the surfaces of the
resist frames 6 is washed by a washing solution 7, and a
development dissolving reaction on the surface of the resist frames
6 is stopped, so that as shown in FIG. 1D, the resist frames 6
patterned into a predetermined shape are formed. As the washing
solution 7, for example, pure water is used.
[0053] After washing is ended, as shown in FIG. 2A, the substrate
is immersed into a plating solution 8 in a plating bath while the
washing solution 7 is not blown away but a layer of the washing
solution 7 is held on the surface of the substrate, and a plating
treatment is carried out using the resist frames 6 as a mold, so
that plating films 9 are formed between the resist frames 6. As the
need arises, a plating pretreatment solution (for example, mixture
solution of surface active agent and acid) may be sprayed on the
surface of the substrate before it is immersed into the plating
solution 8 and washing may be carried out by the washing solution
7. Also in this case, in the state where the washing solution 7 is
not blown away but the washing solution is kept on the surface of
the substrate, the substrate 1 is immersed into the plating
solution 8 in the plating bath.
[0054] Next, in FIG. 2B, as the need arises, water washing and
drying are made, and next, the resist frames 6 are peeled off from
the substrate 1 by using an organic solvent (see FIG. 2C). Next,
the electrode film 2 is removed by dry etching (ion milling,
reactive ion etching (RIE), etc.) or wet etching using the plating
films 9 as a mask (see FIG. 2D). Here, the frame plating method of
this embodiment is completed.
[0055] Like this, in the frame plating method of this embodiment,
in the washing process when the resist frames 6 are formed, a
processing of blowing away the washing solution 7 is not carried
out. Accordingly, since the surface tension of the washing solution
7 when the washing solution 7 is blown away by the rotation of the
substrate 1, the centrifugal force, or the pressing force from the
washing solution 7 are not applied to the resist frames 6, even if
the resist frames 6 has a high aspect ratio, it does not tilt.
[0056] Thus, there does not occur such a case where the washing
solution remains on the surface of the substrate to produce a
stain, like the conventional surface tension reducing method or the
like, and plating abnormality in the plating process can be
decreased. Besides, since it is also not necessary to use a washing
solution having low surface tension, pattern peeling in which the
washing solution intrudes into the interface between the resist
layer and the substrate does not also become problematic.
[0057] Further, in this embodiment, since a general resist material
is used, there does not occur any problem in view of reduction in
cost and reduction in the number of steps, unlike the conventional
resist strength improvement method.
[0058] Accordingly, it becomes possible to easily and certainly
prevent tilting of the resist frame having a high aspect ratio and
to form a desired plating film.
[0059] Incidentally, in the frame plating method according to the
first embodiment, the washing solution in the washing process
carried out at the final stage of a photolithography process is not
dried but is made to remain as it is. However, it is not desirable
that the state where the washing solution is adhered to the
substrate continues for a long time. First, there is a possibility
that a foreign substance such as dust is adhered to the washing
solution on the substrate, and causes a defect in a subsequent
process. Second, there is a possibility that the electrode film for
plating is rusted by water. Third, there is also a possibility that
the resist frame absorbs moisture to swell, and adhesiveness is
deteriorated to cause pattern peeling. Besides, in view of
transportation of the substrate, there is a also a possibility that
a transporting device is wetted during the transportation of the
wet substrate.
[0060] Then, as a second embodiment of the present invention, a
plating apparatus suitably used in the frame plating method
according to the first embodiment will be described with reference
to FIG. 3. FIG. 3 is a schematic view showing an outline structure
of the plating apparatus according to this embodiment. As shown in
FIG. 3, the plating apparatus is roughly divided into a plating
portion 50 used in a plating process and a developing/washing
portion 100 used in a developing/washing process carried out before
the plating process. In FIG. 3, the up and down direction is almost
coincident with the vertical direction, and the right and left
direction is almost coincident with the horizontal direction. The
developing/washing portion 100 is positioned vertically below the
plating portion 50.
[0061] The plating portion 50 includes a plating bath 52 for
containing a plating solution 62. The plating bath 52 includes an
opening portion 90 at a bottom, and the opening peripheral end
portion of the opening portion 90 is brought into close contact
with the peripheral end portion of a substrate 138' transported
from the developing/washing portion 100 thereunder to close the
opening portion 90, so that the plating solution 62 in the plating
bath 52 can be brought into contact with the surface of the
substrate without leaking.
[0062] A cathode 58 is provided at the opening periphery of the
opening portion 90, and an anode 56 is provided in the bath above
the opening portion 90. The anode 56 is connected to a positive
terminal of a DC power source 54, and the cathode 58 is connected
to a negative terminal. When the substrate 138' closes the opening
portion 90, an electrode film on the substrate 138' is electrically
connected to the cathode 58, and a plating treatment is carried out
by a potential difference between the anode 56 and the electrode
film through the plating solution 62. A paddle 60 is provided
between the opening portion 90 and the anode 56. The paddle 60 is
supported to be movable in the direction of arrows A and B above
the substrate 138' almost horizontally. In order to raise the
uniformity of plating, the paddle 60 agitates the plating solution
62 in the vicinity of the surface of the substrate 138' so that a
liquid layer having a different ion concentration is not produced
at the interface between the plating solution 62 and the surface of
the substrate 138'.
[0063] The plating solution 62 contained in the plating bath 52 is
supplied from a plating solution tank 64. In the plating solution
tank 64, there is disposed an agitating wing 74 rotated by a motor
72 at a predetermined revolving speed to agitate the plating
solution 62 in the tank. Besides, in the plating solution tank 64,
a thermocouple 70 for measuring temperature of the plating solution
62 is provided. Temperature data measured by the thermocouple 70 is
sent to a control portion 72, and the control portion 72 controls a
heater 68 provided in the tank to keep the temperature of the
plating solution 62 in the tank at a predetermined temperature.
[0064] The plating solution 62 in the plating solution tank 64 is
introduced in the plating bath 52 by opening a valve 82 and closing
a valve 80 while a pump 78 is operated. Besides, by opening a valve
86, the plating solution 62 in the plating bath is returned in the
plating solution tank 64. The quantity of the plating solution 62
in the plating bath 52 can be adjusted by opening/closing a valve
84.
[0065] The developing/washing portion 100 includes a
developing/washing bath 102. A substrate holder 136 on which a
substrate 138 is mounted is contained in the developing/washing
bath 102. The substrate holder 136 is connected to a coupling rod
140 extending from an air cylinder 132, and can be moved upward and
downward substantially in the vertical direction through the
driving of the air cylinder 132. By moving the coupling rod 140 in
the direction of arrow C in the drawing through the driving of the
air cylinder 132, the substrate 138 mounted on the substrate holder
136 is moved in the direction of arrow C' and can be brought into
close contact with the opening of the bottom of the plating bath
52. A transporting mechanism for transporting the substrate 138 to
the opening portion 90 is constituted by at least the coupling rod
140 and the air cylinder 132.
[0066] Besides, the substrate holder 136 is designed such that the
substrate 138 can be rotated in the direction of arrow E' by
rotating a motor 134 to rotate the coupling rod 140 in the
direction of arrow E in the drawing.
[0067] A developing solution nozzle 104 for spraying the developing
solution onto the surface of the substrate 138 on the substrate
holder 136 is provided in the developing/washing bath 102. The
developing solution nozzle 104 sprays the developing solution in a
developing solution tank 114 onto the substrate 138 by opening a
valve 111 and closing a valve 126 while a pump 120 is operated.
[0068] Besides, a washing solution nozzle 106 for spraying the
washing solution onto the surface of the substrate 138 on the
substrate holder 136 is provided in the developing/washing bath
102. The washing solution nozzle 106 sprays the washing solution in
a washing solution tank 116 onto the substrate 138 by opening a
valve 110 and closing a valve 128 while a pump 122 is operated.
[0069] Further, a plating pretreatment solution nozzle 108 for
spraying the plating pretreatment solution (for example, mixture
solution of surface active agent and acid) onto the surface of the
substrate 138 on the substrate holder 136 is provided in the
developing/washing bath 102. The plating pretreatment solution
nozzle 108 sprays the plating pretreatment solution in a plating
pretreatment solution tank 118 onto the substrate 138 by opening a
valve 112 and closing a valve 130 while a pump 124 is operated.
[0070] A drainage receiving portion for receiving leak drainage of
the plating solution is provided between the plating portion 50 and
the developing/washing portion 100. The drainage receiving portion
includes a drainage receiver 152 and an air cylinder 150 for moving
the drainage receiver 152 in the horizontal direction (direction of
arrow D in the drawing). The plating solution 62 is discharged from
the plating bath 52 to the plating solution tank 64 through the
valve 86, and when the substrate holder 136 goes down, the drainage
receiver 152 is advanced to the position of a broken line 152' by
the driving of the air cylinder 150, and receives the residual
plating solution 62 leaking out from the opening.
[0071] Next, the operation of a plating treatment in the plating
apparatus of this embodiment will be described. When exposure of
the resist layer by a projection exposure device or the like is
ended, the exposed substrate 138 mounted on an X-Y stage of the
exposure device is transported by a substrate transporting device,
and after a heat treatment by a heat treatment device is performed
as the need arises, it is mounted on the substrate holder 136 in
the developing/washing bath 102 of the plating apparatus.
[0072] When the substrate 138 is mounted on the substrate holder
136, the motor 134 is driven to rotate the substrate holder 136 at
a low revolving speed. At the same time, the valve 111 is opened
and the valve 126 is closed while the pump 120 is operated, so that
the developing solution in the developing solution tank 114 is
sprayed onto the whole surface of the substrate 138 from the
developing solution nozzle 104.
[0073] When the predetermined developing treatment is ended, the
valve 126 is opened and the valve 111 is closed so that supply of
the developing solution from the developing solution nozzle 104 is
stopped.
[0074] Next, the valve 110 is opened and the valve 128 is closed
while the pump 122 is operated, so that the washing solution of the
washing solution tank 116 is sprayed onto the substrate 138 from
the washing solution nozzle 106. When the predetermined washing
treatment is ended, the valve 128 is opened and the valve 110 is
closed, so that supply of the washing solution from the washing
solution nozzle 106 is stopped. Incidentally, as the need arises,
spraying of the plating pretreatment solution from the plating
pretreatment solution nozzle 108 and spraying of the washing
solution from the washing solution nozzle 106 onto the substrate
138 are carried out.
[0075] When the above process is ended, the rotation of the
substrate holder 136 is stopped, and in the state where the washing
solution is not blown away from the substrate 138 but the washing
solution is held, the substrate holder 136 is lifted to the opening
portion 90 of the plating bath 52.
[0076] The coupling rod 140 is moved in the direction of the arrow
C in the drawing by the driving of the air cylinder 132, so that
the substrate 138 mounted on the substrate holder 136 is brought
into close contact with the opening of the opening portion 90 of
the bottom of the plating bath 52. By this, the opening of the
bottom of the plating bath 52 is closed by the substrate 138', and
the electrode film on the substrate 138' is electrically connected
to the cathode 58.
[0077] Next, the valve 82 is opened and the valve 80 is closed
under the operation of the pump 78, so that the plating solution 62
in the plating solution tank 64 is introduced in the plating bath
52.
[0078] When the plating solution 62 reaches a predetermined level
in the plating bath 52, a predetermined voltage is applied between
the anode 56 and the cathode 58 from the DC power source 54 to
start the plating treatment. The washing solution adhering to the
surface of the substrate 138' is diffused into the plating solution
62, and further, the agitating operation of the paddle 60 is made,
and electrical plating is carried out between the electrode film on
the substrate 138' being in contact with the cathode 58 and the
anode 56. By this, plating metal is deposited between the resist
frames on the substrate 138' and a plating film is formed.
[0079] After the predetermined plating film is formed, supply of
electric power from the DC power source 54 is cut to stop the film
growth of the plating film. Incidentally, in the plating treatment,
while the plating solution 62 is introduced from the plating
solution tank 64 through the valve 82, the plating solution 62 is
discharged through the valves 84 and 86 to the plating solution
tank 64, so that the plating solution 62 in the plating bath 52 is
circulated.
[0080] Next, the valve 80 is opened and the valve 82 is closed, and
the valve 86 is opened so that the plating solution 62 in the
plating bath 52 is discharged to the plating solution tank 64. When
the discharge of the plating solution 62 is completed, the air
cylinder 132 is driven to make the substrate holder 136 go down. At
the same time, the air cylinder 150 is driven to move the drainage
receiver 152 to the position below the opening of the bottom of the
plating bath 52, so that the leak drainage of the plating solution
62 is received.
[0081] The substrate 138 descending to a predetermined position,
together with the substrate holder 136, is rotated by the motor 134
at a low speed, and at the same time, the valve 110 is opened and
the valve 128 is closed while the pump 122 is operated, so that the
washing solution in the washing solution tank 116 is sprayed onto
the substrate 138 from the washing solution nozzle 106. Next, the
substrate 138 is transported by a not-shown substrate transporting
system and is transported to a processing device of a next
process.
[0082] Like this, according to this embodiment, a state where the
washing solution adheres to the substrate does not continue for a
long time, and it is possible to extremely lower the possibility
that a foreign substance such as dust adheres to the washing
solution on the substrate. Besides, since a time when moisture is
in contact with the electrode film for plating can be suppressed to
a very short time, it is possible to almost completely remove the
possibility that rust is generated in the electrode film. Besides,
it is also possible to avoid the possibility that the resist frame
absorbs moisture to swell. Further, since substrate transportation
by a conventional substrate transporting system is not carried out,
there does not occur such a case that an existing transporting
device is wetted by a wet substrate.
[0083] Next, as a third embodiment of the present invention, a
manufacturing method of a thin film magnetic head using the frame
plating method according to the first embodiment will be described
with reference to FIGS. 4A to 4H and FIGS. 5A to 7C. FIGS. 4A to 4H
are process sectional views showing the manufacturing method of the
thin film magnetic head, FIGS. 4A to 4D are sectional views taken
along a plane passing through the center of a track of the magnetic
head, and FIGS. 4E to 4H are sectional views seen in the direction
of an air bearing surface (ABS).
[0084] This embodiment shows a case of a composite type thin film
magnetic head in which an inductive recording head and a
magnetoresistive effect (MR) reproduction head portion are
integrally laminated. However, it is needless to say that the frame
plating method of the embodiment can also be applied to a thin film
magnetic head in which only an inductive recording head portion is
provided.
[0085] First, an insulating layer 10 is laminated on a not-shown
substrate made of a ceramic material such as Al.sub.2O.sub.3TiC.
This insulating layer 10 is formed to a thickness of about 1 to 2
.mu.m by a sputtering method or the like from an insulating
material such as Al.sub.2O.sub.3 or SiO.sub.2.
[0086] Next, a layer for a lower shield 11 is laminated thereon,
and further, an insulating layer 12 for a shield gap is laminated
thereon. The layer for the lower shield 11 is formed preferably to
a thickness of about 100 to 5000 nm by the sputtering method,
plating method or the like from a material such as AlFeSi, NiFe,
CoFe, CoFeNi, FeN, FeZrN, FeTaN, CoZrNb, or CoZrTa. The insulating
layer 12 for the shield gap is formed preferably to a thickness of
about 10 to 200 nm by the sputtering method or the like from an
insulating material such as Al.sub.2O.sub.3 or SiO.sub.2.
[0087] Next, an MR component 13 on the insulating layer 12 is
formed, and a lead conductor 14 is formed to be electrically
connected to both ends of the MR element 13. Although the MR
element 13 may be made to have a single layer structure of a
magnetic material, it is desirable to make a multi-layer structure
in which a magnetic layer and a nonmagnetic layer are alternately
laminated. As the material of the magnetic layer, NiFe, NiFeRh,
FeMn, NiMn, Co, Fe, NiO, NiFeCr, or the like is preferable, and as
the material of the nonmagnetic layer, Ta, Cu, Ag or the like is
preferable. Besides, as the multi-layer structure, for example, a
three layer structure of NiFeRh/Ta/NiFe, or a plural-layer
structure of NiFe/Cu/NiFe/FeMn, NiFe/Cu/Co/FeMn, Cu/Co/Cu/NiFe,
Fe/Cr, Co/Cu, Co/Ag, or the like is made one unit, and a plurality
of such units may be laminated. In the case of the multi-layer
structure, it is preferable that the thickness of the magnetic
layer is made 0.5 to 50 nm, especially 1 to 25 nm, and the
thickness of the nonmagnetic layer is also made 0.5 to 50 nm,
especially 1 to 25 nm. It is preferable that the number of repeated
laminate layers of the units is 1 to 30, especially 1 to 20. It is
preferable that the thickness of the whole of the MR component 13
is 5 to 100 nm, especially 10 to 60 nm. In order to laminate the
layers for the MR component, the sputtering method, plating method
or the like is used. It is preferable that the lead conductor 14 is
formed to a film thickness of 10 to 500 nm, especially about 50 to
300 nm by the sputtering method, plating method or the like from a
conductive material such as W, Cu, Au, Ag, Ta, Mo, Co, or Pt.
[0088] Next, an insulating layer 15 for a shield gap is laminated
on the MR component 13 and the lead conductor 14. This insulating
layer 15 is formed to a thickness of 5 to 500 nm, preferably 10 to
200 nm by the sputtering method or the like from an insulating
material such as Al.sub.2O.sub.3 or SiO.sub.2.
[0089] The respective layers of the MR reproduction head portion
described above are patterned by a general liftoff method using a
resist pattern, a milling method, or a method using both these
methods.
[0090] Next, a magnetic layer for a lower magnetic pole 16 of a
recording head portion also serving as an upper shield of the MR
component 13 is laminated, and an insulating layer for a recording
gap 17 is laminated thereon. The layer for the lower magnetic pole
16 is formed to a thickness of about 500 to 4000 nm by the plating
method, sputtering method or the like from a soft magnetic material
such as NiFe, CoFe, CoFeNi, or FeN. The insulating layer for the
recording gap 17 is formed to a thickness of about 10 to 500 nm by
the sputtering method or the like from a material such as
Al.sub.2O.sub.3 or SiO.sub.2.
[0091] Thereafter, a coil 18 and an insulating layer 19 surrounding
this coil 18 are formed on the recording gap 17. The coil 18 is
formed to a thickness of about 2 to 5 .mu.m by the frame plating
method or the like from a conductive material such as Cu. The
insulating layer 19 is formed to a thickness of about 3 to 20 .mu.m
by thermally hardening a photoresist material.
[0092] The layer structure as shown in FIGS. 4A and 4E is obtained
through the above steps. Incidentally, the coil 18 may have two
layers as shown in the drawing, or three layers or more, or may
have a single layer.
[0093] Next, as shown in FIGS. 4B and 4F, an upper magnetic pole 20
including a magnetic pole portion at an ABS side and a yoke portion
at a rear side is formed on the thus formed insulating layer 19 by
the frame plating method. The upper magnetic pole 20 is formed to a
thickness of about 3 to 5 .mu.m from a soft magnetic material such
as NiFe, CoFe, CoFeNi, or FeN . At this time, the shape of the
magnetic pole portion of the upper magnetic pole 20 seen from the
ABS side is formed to be as shown in the drawing.
[0094] Hereinafter, the frame plating method for forming the upper
magnetic pole 20 having the shape like this will be described.
FIGS. 5A to 7C are process sectional views showing a forming
process of the upper magnetic pole by the frame plating method
according to the embodiment.
[0095] As shown in FIG. 5B, a metal under film 21 having preferably
the same constituent as the layer to be plated, such as Cu, NiFe,
or Au, is formed to a thickness of about 10 to 500 nm on the
recording gap 17 shown in FIG. 5A.
[0096] Next, as shown in FIG. 5C, a resist material 22 is coated on
the metal under film 21 and is patterned to form a resist pattern
23 as shown in FIG. 5D. In the formation of the resist pattern 23,
a developing solution on the surface of the resist pattern 23 is
washed by a washing solution 27 in a washing process subsequent to
a developing process, and a development dissolving reaction of the
surface of the resist pattern 23 is stopped. When the washing is
ended, as described in the first embodiment, in the state where the
washing solution 27 is not blown away but the layer of the washing
solution 27 is held on the surface of the substrate, the substrate
is immersed into a plating solution in a plating bath, and as shown
in FIG. 6A, the resist pattern 23 is used as a mold, and a plating
layer 24 is obtained by plating of a soft magnetic material such as
NiFe, CoFe, CoFeNi, or FeN.
[0097] Next, as shown in FIG. 6B, the resist pattern 23 is peeled
off by using an organic resin or the like. Next, as shown in FIG.
6C, the metal under film 21 after the removal of the resist pattern
is removed by means such as ion milling by using the plating film
24 as a mask.
[0098] Next, as shown in FIG. 7A, an upper part and a periphery of
a portion of the plating layer 24 to be left are covered with a
resist layer 25. Next, as shown in FIG. 7B, the plating layer 24
and the metal under film 21 at an unnecessary portion are removed
by wet etching or the like, and further, the resist layer 25 is
peeled off by using an organic solvent or the like, so that the
upper magnetic pole 20 as shown in FIG. 7C is formed.
[0099] With respect to FIGS. 4A to 4H again, as shown in FIGS. 4C
and 4G, the thus formed upper magnetic pole 20 is used as a mask,
and dry etching such as ion milling or RIE (reactive ion etching)
is carried out, so that a portion not covered with the mask of the
insulating layer for the recording gap 17 is removed, and further,
a portion not covered with the mask is removed to the middle of the
magnetic layer for the lower magnetic pole 16.
[0100] By this, as shown in FIGS. 4D and 4H, a protrusion 16a
opposite to the lower end of the upper magnetic pole 20 through the
recording gap 17 and having the same width is formed at the lower
magnetic pole 16. Next, after a pad bump or the like is formed, a
protective layer 26 is laminated. This protective layer 26 is
formed to a film thickness of about 5 to 50 .mu.m by the sputtering
method or the like from an insulating material such as
Al.sub.2O.sub.3 or SiO.sub.2.
[0101] As described above, in this embodiment, since the frame
plating method according to the first embodiment is used, the
processing of blowing away the washing solution is not carried out
in the washing process when the resist pattern 23 is formed.
Accordingly, since the surface tension of the washing solution when
the washing solution is blown away by rotating the substrate 10,
the centrifugal force, and the pressing force from the washing
solution are not applied to the resist pattern 23, even if an
aspect ratio is high, the resist pattern 23 does not tilt.
Accordingly, tilting of the resist pattern 23 having a high aspect
ratio can be easily and certainly prevented and a desired plating
film can be formed, and it becomes possible to manufacture a thin
film magnetic head at low cost and with high accuracy.
[0102] The present invention is not limited to the above
embodiments, but various modifications can be made.
[0103] For example, in the above embodiment, although the present
invention is applied to the formation of the upper magnetic pole,
it is naturally possible to apply the present invention to
formation of a pattern formed by another frame plating method, for
example, formation of a coil.
[0104] Besides, for example, although the description has been made
on the thin film magnetic head as an example, the present invention
is not limited to this, but can be widely applied to manufacture of
a device (micro device) having a fine structure, including a
semiconductor device.
[0105] As described above, according to the present invention, it
is possible to realize a frame plating method in which tilting of a
resist frame having a high aspect ratio can be easily and certainly
prevented and a desired plating film can be formed, and a
manufacturing method of a thin film magnetic head using the
method.
* * * * *