U.S. patent application number 11/007186 was filed with the patent office on 2005-05-19 for apparatus for manufacturing magnetic recording disk, and in-line type substrate processing apparatus.
Invention is credited to Furukawa, Shinji, Sasaki, Hiromi, Tani, Kazunori, Watabe, Osamu, Watanabe, Naoki, Watanabe, Nobuyoshi.
Application Number | 20050103271 11/007186 |
Document ID | / |
Family ID | 18550343 |
Filed Date | 2005-05-19 |
United States Patent
Application |
20050103271 |
Kind Code |
A1 |
Watanabe, Naoki ; et
al. |
May 19, 2005 |
Apparatus for manufacturing magnetic recording disk, and in-line
type substrate processing apparatus
Abstract
An apparatus for manufacturing a magnetic recording disk
includes a magnetic-film deposition chamber in which a magnetic
film for a recording layer is deposited on a substrate; a
lubricant-layer preparation chamber in which a lubricant layer is
prepared on the substrate in vacuum; and a cleaning chamber in
which the substrate is cleaned in vacuum after the magnetic-film
deposition in the magnetic-film chamber and before the
lubricant-layer preparation in the lubricant-layer chamber. The
apparatus may further include a transfer system that transfers the
substrate from the cleaning chamber to the lubricant-layer
preparation chamber without exposing the substrate to the
atmosphere.
Inventors: |
Watanabe, Naoki; (Tokyo,
JP) ; Watanabe, Nobuyoshi; (Tokyo, JP) ; Tani,
Kazunori; (Tokyo, JP) ; Furukawa, Shinji;
(Tokyo, JP) ; Sasaki, Hiromi; (Tokyo, JP) ;
Watabe, Osamu; (Tokyo, JP) |
Correspondence
Address: |
HAUPTMAN KANESAKA BERNER PATENT AGENTS
SUITE 300, 1700 DIAGONAL RD
ALEXANDRIA
VA
22314-2848
US
|
Family ID: |
18550343 |
Appl. No.: |
11/007186 |
Filed: |
December 9, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11007186 |
Dec 9, 2004 |
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10405487 |
Apr 3, 2003 |
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10405487 |
Apr 3, 2003 |
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09774887 |
Feb 1, 2001 |
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6572934 |
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Current U.S.
Class: |
118/719 ;
118/723R; G9B/5.295 |
Current CPC
Class: |
Y10S 414/135 20130101;
Y10S 414/139 20130101; Y10S 414/136 20130101; Y10S 414/137
20130101; C23C 14/352 20130101; C23C 16/26 20130101; Y10S 414/138
20130101; G11B 5/84 20130101; G11B 5/8408 20130101; Y10S 414/14
20130101; Y10S 414/141 20130101; C23C 14/568 20130101; C23C 14/50
20130101 |
Class at
Publication: |
118/719 ;
118/723.00R |
International
Class: |
B05D 005/12; B32B
001/00; C23C 014/02; C23C 016/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 1, 2000 |
JP |
2000-24334 |
Claims
What is claimed is:
1. An apparatus for manufacturing a magnetic recording disk,
comprising: a magnetic-film deposition chamber in which a magnetic
film for a recording layer is deposited on a substrate; a
lubricant-layer preparation chamber in which a lubricant layer is
prepared on the substrate in vacuum; and a transfer system that
transfers the substrate from the magnetic-film deposition chamber
to the lubricant-layer preparation chamber without exposing the
substrate to atmosphere.
2. An apparatus for manufacturing a magnetic recording disk,
comprising: a magnetic-film deposition chamber in which a magnetic
film for a recording layer is deposited on a substrate; a
lubricant-layer preparation chamber in which a lubricant layer is
prepared on the substrate in vacuum; and a cleaning chamber in
which the substrate is cleaned in vacuum after the magnetic-film
deposition in the magnetic-film chamber and before the
lubricant-layer preparation in the lubricant-layer chamber.
3. An apparatus for manufacturing a magnetic recording disk as
claimed in claim 2, wherein, in said cleaning chamber, contaminants
adhering to the substrate are removed by oxidizing the contaminants
into volatile oxides, utilizing a reaction with oxygen ion or
activated oxygen produced in oxygen plasma generated at a space
facing the substrate.
4. An apparatus for manufacturing a magnetic recording disk as
claimed in claim 2, wherein, in said cleaning chamber, contaminants
adhering to the substrate are removed by energy of laser beam
irradiated onto the substrate.
5. An apparatus for manufacturing a magnetic recording disk as
claimed in claim 2, wherein, in said cleaning chamber, gas is blown
onto the substrate, thereby blowing contaminants adhering to the
substrate away from the substrate.
6. An apparatus for manufacturing a magnetic recording disk as
claimed in claim 2, further comprising a transfer system that
transfers the substrate from the cleaning chamber to the
lubricant-layer preparation chamber without exposing the substrate
to the atmosphere.
7. An apparatus for manufacturing a magnetic recording disk,
comprising: a magnetic-film deposition chamber in which a magnetic
film for a recording layer is deposited on a substrate; an overcoat
deposition chamber in which an overcoat is deposited on the
substrate after the magnetic-film deposition, said overcoat
deposition chamber comprising means for generating plasma in which
oxygen ion or activated oxygen is produced, said oxygen ion or said
activated oxygen oxidizing contaminants on the substrate into
volatile oxides, thereby removing the contaminants; and a transfer
system that transfers the substrate from the magnetic-film
deposition chamber to the overcoat deposition chamber without
exposing the substrate to atmosphere.
8. An apparatus for manufacturing a magnetic recording disk,
comprising: a magnetic-film deposition chamber in which a magnetic
film for a recording layer is deposited on a substrate; and a
burnishing chamber in which a burnishing is carried out in vacuum
after the magnetic-film deposition, said burnishing being a step
where protrusions on the substrate are removed.
9. An apparatus for manufacturing a magnetic recording disk as
claimed in claim 8, further comprising a lubricant-layer
preparation chamber in which a lubricant layer is prepared on the
substrate after the burnishing, and a transfer system that
transfers the substrate from the burnishing chamber to the
lubricant-layer preparation chamber without exposing the substrate
to the atmosphere.
10. An apparatus for manufacturing a magnetic recording disk as
claimed in claim 8, wherein said burnishing chamber comprises a
burnishing tape that is rubbed against the substrate for the
burnishing, and cleaning means for cleaning a surface of the
burnishing tape prior to the burnishing.
11. An apparatus for manufacturing a magnetic recording disk,
comprising; a magnetic-film deposition chamber in which a magnetic
film for a recording layer is deposited on a substrate, a
lubricant-layer preparation chamber in which a lubricant layer is
prepared on the substrate after the magnetic-film deposition, and a
post-preparation treatment chamber in which a post-preparation
treatment is carried out onto the substrate in vacuum, said
post-preparation treatment being a step of controlling adhesive
strength and surface lubricity of the lubricant layer by heating or
irradiating the lubricant layer.
12. An apparatus for manufacturing a magnetic recording disk as
claimed in claim 11, further comprising a transfer system that
transfers the substrate from the lubricant-layer preparation
chamber to the post-preparation treatment chamber without exposing
the substrate to the atmosphere.
13. An in-line type substrate processing apparatus, comprising: a
plurality of circumventive transfer paths; a plurality of vacuum
chambers provided along the transfer paths; a connection transfer
path connecting at least two of the circumventive transfer paths;
and a transfer system that transfers a substrate to be processed
along the circumventive transfer paths, and transfers the substrate
along the connection transfer path without exposing the substrate
to atmosphere.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This is a divisional application of a patent application
Ser. No. 10/405,487 filed on Apr. 3, 2003, which is a divisional
application of a patent application Ser. No. 09/774,887, filed on
Feb. 1, 2001.
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
[0002] This invention relates to an apparatus for manufacturing
magnetic recoding disks. Especially, this invention relates to an
apparatus performing a manufacturing method including a step of
removing protrusions on a substrate and a step of forming a
lubricant film on the substrate.
[0003] The manufacture of a magnetic recording disk such as a hard
disk is roughly divided into former steps and latter steps. The
former steps include deposition of an underlying film, deposition
of a magnetic film for a recording layer, and deposition of an
overcoat. The latter steps include preparation of a lubricant layer
and other required steps. The lubricant layer is prepared
considering contact of a magnetic head onto the disk in
read-out.
[0004] The preparation of the lubricant layer is carried out by a
following procedure.
[0005] To begin with, a substrate is taken out to the atmosphere
after deposition steps because thin-films such as the magnetic film
for a recording layer are usually deposited in a vacuum chamber.
Then, burnishing is carried out to remove contaminants adhering to
the substrate and to remove protrusions formed on the substrate
during the film depositions. The burnishing is a step of removing
the protrusions and the contaminants from the substrate by rubbing
it with a tape-shaped polishing member. The "contaminant" in this
specification means materials that may contaminate a substrate in
general, which is a gas, ions, molecules, particles or other
substances.
[0006] The lubricant layer is prepared after the burnishing. As
lubricant, fluorine lubricant such as perfluoropolyether (PFPE) is
used. Such lubricant is diluted with solvent for improving
uniformity. The diluted lubricant is coated onto the substrate by
such method as a dipping method where the substrate is dipped into
the diluted lubricant, or a spin-coating method where the lubricant
is dropped onto the substrate when it is spun.
[0007] "Substrate" means a board that consists a magnetic recording
disk in this specification. "Surface of substrate" may mean a
surface of a film or layer when a film deposition or a layer
preparation has already been carried out onto the substrate.
[0008] Recent improvement of recording density in magnetic
recording disks is remarkable. For example, in hard disks it is
becoming 20 gigabit/inch2 in the year 2000 and 40 gigabit/inch2 in
the year 2001. One of factors that enable the improvement of the
recording density is to reduce a spacing. FIG. 19 shows a view
explaining the spacing.
[0009] In FIG. 19, the spacing in the case of hard disks is
explained as an example. As shown in FIG. 19, a hard disk has a
structure where a recording layer 91 is prepared on a substrates 9,
an overcoat 92 is deposited on the recording layer 91, and a
lubricant layer 93 is prepared on the overcoat 92. A magnetic head
for writing and reading information is located at a position
slightly apart from the surface of the hard disk. The spacing,
which is designated by "S" in FIG. 19, means distance between a
write-readout device element 900 of the magnetic head and the
recording layer 91 of the hard disk. A distance between the
write-readout device element 900 and the lubricant layer 93 is
called a "flying height", which is designated by "FH" in FIG. 19.
It is important to make the spacing S small in improving the
recording density.
[0010] As the spacing S becomes smaller, demands to the
manufacturing process have been becoming severer by years. For
reducing the spacing S, it is required not only to reduce the
flying height FH, which is about 10 to 20 nm in a typical hard disk
drive (HDD) currently on sale in the market, but also required to
make a thickness of the overcoat 92 and a thickness of the
lubricant layer 93 thinner. As thickness of the overcoat 92 is made
thinner, it is required to deposit a more compact and harder film
as the overcoat 92. As the thickness of overcoat 92 is made
thinner, a demand for thickness uniformity of the lubricant layer
93 becomes severer as well as a demand for enhancing an adhesion
strength of the lubricant layer 93 becomes severer.
[0011] With the above described points in the background, a method
for depositing the overcoat 9 has been shifting from a conventional
sputtering method to a chemical vapor deposition (CVD) method.
Usually a carbon film is deposited as the overcoat 92. By the CVD
method, it is enabled to deposit a carbon film called a
"diamond-like carbon" (DLC) film. The DLC film is known as a hard,
compact and stable carbon film even when its thickness is small.
This is the reason why the method has been shifting to the CVD
method.
[0012] However, the contaminants of gases or ions may adhere to the
overcoat 92 under influence of residual gases when it is deposited
by the CVD method. In addition, minute protrusions are easily
formed on the overcoat 92 in the CVD method, resulting from
abnormal film growth. If the lubricant layer 93 is prepared over
the overcoat 92 on which the contaminants or the protrusions exist,
there easily arise problems such as the adhesion strength of the
lubricant layer 93 may decrease, and the thickness of the lubricant
layer 93 may lose uniformity.
[0013] The adhesion strength of the lubricant layer 93 is enhanced
when terminal groups of macromolecules composing the lubricant are
bonded sufficiently with carbons in the overcoat 92. For making the
adhesion strength higher, it is preferable that the macromolecules
are bonded with carbons in the surface of the overcoat 92 at one of
or both terminal groups. On the other hand, it is desirable that a
degree of freedom of the macromolecules is high at a portion
adjacent to the surface of the lubricant layer 93, on purpose of
prevention the write-readout device element 900 of the magnetic
head from chucking with the disk. In short, both terminal groups
are preferably not bonded near the surface of the lubricant
layer.
[0014] A macromolecule bonded with a carbon at one of or both
terminal groups is hereinafter called a "bonded lub". A
macromolecule not bonded with a carbon at either of terminal groups
is hereinafter called a "free lub". A thickness ratio of the bonded
lub layer against the whole lubricant layer 93 is hereinafter
called a "bonded ratio". Though an optimum bonded ratio has been
supposed about 20-30% so far, a demand for accuracy of the bonded
ratio tends to be severer as the lubricant layer 93 is made
thinner.
[0015] For obtaining the demanded bonded ratio, it has been
attempted to carry out treatment for controlling the bonds of the
terminal groups after the lubricant-layer preparation. In this
treatment, thermal energy or light energy is applied to the
lubricant layer 93, thereby controlling the bonds of the terminal
groups. This treatment is hereinafter called "post-preparation
treatment".
[0016] However, when the overcoat 92 is exposed to the atmosphere
after the deposition, many contaminants of gases or ions in the
atmosphere are adsorbed with the surface of the overcoat 92 because
the surface has been chemically activated. As a result, when the
lubricant layer 93 is prepared, a contaminated layer may be formed
between the lubricant layer 93 and the overcoat 92. If the
contaminated layer is formed, it may become difficult to obtain an
accurate bonded ratio by the post-preparation treatment. For
preventing these problems, equipment that reduces the contaminants
is required. Including such a point, the current situation is that
huge investment is inevitable for coordinating manufacture
environment.
[0017] An object of the invention is to solve the described
problems in the manufacturing process, which have been brought from
the reduction of the spacing.
SUMMARY OF THE INVENTION
[0018] To accomplish this object, the invention presents a method
and an apparatus for manufacturing a magnetic recording disk, where
steps from magnetic-film deposition to lubricant-layer preparation
are carried out without breaking vacuum. The invention also
presents a method and an apparatus for manufacturing a magnetic
recording disk, where a substrate is cleaned prior to
lubricant-layer preparation. The invention also presents a method
and an apparatus for manufacturing a magnetic recording disk, where
burnishing is carried out in vacuum after magnetic-film deposition.
The invention also presents a method and an apparatus for
manufacturing a magnetic recording disk, where post-preparation
treatment to coordinate adhesive strength and surface lubricity of
a lubricant layer is carried out in vacuum. The invention also
presents an in-line type substrate processing apparatus comprising
a plurality of vacuum chambers provided along each of a plurality
of circumventive transfer paths, a connection transfer path
connecting at least two of the circumventive transfer paths, and a
transfer system that transfers a substrate to be processed along
the circumventive transfer paths and the connection transfer path
without exposing the substrate to the atmosphere.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 shows a schematic plane view of a magnetic recording
disk manufacturing apparatus of the first embodiment of the
invention.
[0020] FIG. 2 shows a schematic front view of the first substrate
holder 51 and a linear transfer mechanism in the apparatus shown in
FIG. 1.
[0021] FIG. 3 shows a schematic side cross-sectional view of the
first substrate holder 51 and the linear transfer mechanism in the
apparatus shown in FIG. 1
[0022] FIG. 4 shows a schematic side view of a direction-conversion
mechanism provided in a direction-changing chamber 17 shown in FIG.
1.
[0023] FIG. 5 shows a schematic plane view of a magnetic-film
deposition chamber 14 shown in FIG. 1.
[0024] FIG. 6 shows a schematic plane view of an overcoat
deposition chamber 15 shown in FIG. 1.
[0025] FIG. 7 shows a schematic plane view the first cleaning
chamber 22 shown in FIG. 1.
[0026] FIG. 8 shows a schematic plane view of the second cleaning
chamber 22 shown in FIG. 1.
[0027] FIG. 9 shows a schematic side view of a burnishing chamber
24 shown in FIG. 1.
[0028] FIG. 10 shows a schematic cross-sectional view of a rotation
mechanism 8 shown in FIG. 9.
[0029] FIG. 11 shows a front view explaining locations of contact
blades 821 shown in FIG. 10.
[0030] FIG. 12 shows s schematic side view of a drive mechanism 87
that drives a pusher 247 shown in FIG. 9.
[0031] FIG. 13 shows a schematic side view of a lubricant-layer
preparation chamber 25 shown in FIG. 1.
[0032] FIG. 14 shows a schematic side view of a post-preparation
treatment chamber 26 shown in FIG. 1.
[0033] FIG. 15 shows a main part of a magnetic recording disk
manufacturing apparatus of the second embodiment of the
invention.
[0034] FIG. 16 shows a main part of a magnetic recording disk
manufacturing apparatus of the third embodiment of the
invention.
[0035] FIG. 17 shows a main part of a magnetic recording disk
manufacturing apparatus of the fourth embodiment of the
invention.
[0036] FIG. 18 shows a main part of a magnetic recording disk
manufacturing apparatus of the fifth embodiment of the
invention.
[0037] FIG. 19 shows a view explaining a spacing.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0038] Preferred embodiments of this invention are described as
follows.
[0039] FIG. 1 shows a schematic plane view of a magnetic recording
disk manufacturing apparatus of the first embodiment of the
invention. The first point characterizing the first embodiment is
that the former steps such as preparation of a recording layer and
the latter steps such as preparation of a lubricant layer can be
carried out through only one apparatus. The second point
characterizing the first embodiment is that each step from the
recording layer preparation to the lubricant-layer preparation can
be carried out continuously in vacuum, i.e. without taking out a
substrate 9 to the atmosphere.
[0040] In the concrete, the apparatus shown in FIG. 1 is an in-line
type apparatuses where a plurality of vacuum chambers 10-17, 20-29
is arranged along transfer paths 1,2 of the substrates 9. Each
vacuum chamber 10-17, 20-29 is an airtight chamber pumped by a
respective or a common pumping system (not shown). In each boundary
of the vacuum chambers 10-17, 20-29, a gate valve 4 is
provided.
[0041] A plurality of the vacuum chambers 10-17, 20-29 is divided
into the first group of the chambers 10-17 arranged along the first
rectangular transfer path (hereinafter, the first transfer path) 1,
and the second group of the chambers 20-29 arranged along the
second rectangular transfer path (hereinafter, the second transfer
path) 2. The third transfer path 3 connecting the first transfer
path 1 and the second transfer path 2 is provided. A vacuum chamber
31 is also provided on the third transfer path 3. This vacuum
chamber 31 on third transfer path 3 is connected airtightly with
one vacuum chamber 16 of the first group and one vacuum chamber 21
of the second group so that the substrate 9 can be transferred from
the first transfer path 1 to the second transfer path 2 without
being taken out to the atmosphere.
[0042] In the vacuum chambers 10-17 of the first group, steps from
the underlying-film deposition to the overcoat deposition are
carried out. In the vacuum chambers 20-29 of the second group,
steps after the overcoat deposition to the lubricant-layer
preparation are carried out.
[0043] A composition of a transfer system that transfers the
substrate 9 through the first, the second and the third transfer
paths 1,2,3 is described as follows. The transfer system is mainly
composed of the first circulation means that circulates the first
substrate holder 51 holding the substrate 9 along the first
transfer path 1, a loading robot 61 that loads the substrate 9 to
the substrate holder 51 on the first transfer path 1, the second
circulation means that circulates the second substrate holder 52
holding the substrate 9, an unloading robot 62 that unloads the
substrate 9 from the substrate holder 52 on the second transfer
path 2, and a shifting robot 63 that unloads the substrate 9 from
the first substrate holder 51 and loads it to the second substrate
holder 52.
[0044] The loading robot 61, the unloading robot 62 and the
shifting robot 63 are all the same robot basically, which comprises
a multi-articulation arm for holding the substrate 9 at a tip of
the arm. The first and the second substrate holders 51,52 are also
the same composition. The first and the second circulation means
are basically the same composition as well. As an example, the
compositions of the first substrate holder 51 and the first
circulation means are described as follows.
[0045] The first circulation means is mainly composed of a linear
movement mechanism that moves the first holders 51 linearly on the
first transfer path 1, and a direction-conversion mechanism that
converts a transfer direction of the first substrate holder 51. The
compositions of the first substrate holder 51 and the linear
movement mechanism are described as follows using FIG. 2 and FIG.
3. FIG. 2 and FIG. 3 show the first substrate holder 51 and the
linear movement mechanism employed in the apparatus shown in FIG.
1. FIG. 2 shows a front view of them and FIG. 3 shows a side
cross-sectional view of them.
[0046] The first substrate holder 51 is mainly composed of a main
board 511 and pallets 512 fixed with the main board 511. Eight
pallets 512 are provided. Each group of four pallets 512 holds one
substrate 9. Therefore, in this embodiment, the first substrate
holder 51 simultaneously holds two substrates 9. As shown in FIG.
2, the main board 511 has two cutouts. A shape of each cutout is
nearly circle and a little larger than the substrate 9. In each
group of the pallets 512, two pallets 512 are fixed at one side
edge of each cutout. The other two pallets 512 are fixed the other
side edge of each cutout. The substrate 9 is sandwiched between two
couples of the pallets 512.
[0047] The main board 511 has another cutout elongated downward
from both sides of each nearly circular cutout. A vertically
elongated spring band 514 is provided in each cutout. A mount 515
is fixed at the top of each spring band 514. As shown in FIG. 2,
the mount 515 is a nearly trapezoid-shaped plate. The pallet 512 is
fixed on the top and the bottom of the mount 515 by screwing. The
edge of each pallet 512 is V-shaped in which the edge of the
substrate 9 is inlet.
[0048] Each robot 61, 62, 63 has a couple of levers 60 that curve a
couple of spring bands 514 against elasticity so that the pallets
512 shift away from the nearly circular cutout. A loading operation
of the substrate 9 onto the first substrate holder 51 is described
as follows. First, the levers 60 curve the spring bands 514. In
this state, the substrate 9 is located at the center of the nearly
circular cutout. Afterward, the levers 60 are returned to the
initial position so that the spring bands 12 can restore the
initial posture on elasticity. As a result, the substrate 9 is
caught by the four pallets 512. By repeating the same operation so
that the other substrate 9 is caught by the other four pallets 512,
two substrates 9 are held by the first substrate holder 51. The two
substrates 9 are unloaded from the first substrate holder 51 by an
operation quite reverse to this loading operation.
[0049] As shown in FIG. 2, many small magnets 513 are provided at
the bottom of the first substrate holder 51. These magnets 513 are
hereinafter called "holder magnets". Each holder magnet 513 has
magnetic poles on the top and the bottom. As shown in FIG. 2, the
magnetic poles of the holder magnets 513 are alternatively opposite
in an array direction.
[0050] Beneath the first substrate holder 51, a magnetic-coupling
roller 711 is provided, interposing a partition wall 70. The
magnetic-coupling roller 711 is a cylinder, on which two spirally
elongated magnets 712 are provided as shown in FIG. 2. These
magnets 712 are hereinafter called "roller magnets". A surface pole
of each roller magnet 712 is opposite to each other. In short, the
magnetic-coupling roller 711 has a so-called double-helix
structure.
[0051] The magnetic-coupling roller 711 is provided at a position
where the roller magnets 712 face to the holder magnet 513 through
the partition wall 70. The partition wall 70 is formed of material
with a high magnetic permeability. The holder magnets 513 and the
roller magnets 712 are magnetically coupled with each other. One
side of the partition wall 70 where the first substrate holder 51
is provided is a space kept at a vacuum pressure. The other side of
the partition wall 70 where the magnetic-coupling roller 711 is
provided is a space of the atmospheric pressure. The
magnetic-coupling roller 711 is provided along the first transfer
path 1 shown in FIG. 1.
[0052] A multiplicity of main pulleys 714 that are rotated around
horizontal axes are provided along the first transfer path 1. As
shown in FIG. 3, the first substrate holder 51 rides on the main
pulleys 714. A couple of sub-pulleys 715,715 are contacted with a
lower margin of the first substrate holder 51. The sub-pulleys
714,715 pinch the lower margin of the first substrate holder 51 to
prevent fall of the first substrate holder 51. A multiplicity of
the sub-pulleys 715, 715 are provided along the first transfer path
1 as well.
[0053] As shown in FIG. 3, a drive rod 716 is connected with the
magnetic-coupling roller 711 through a bevel gear. A motor 717 is
connected with the drive rod 716 so that the magnetic-coupling
roller 711 can be rotated around its center axis by driving force
transferred from the motor 717 through the drive rod 716.
[0054] When the magnetic-coupling roller 711 is rotated, the
double-helix roller magnets 712 shown in FIG. 2 are also rotated.
Situation that the roller magnets 712 are rotated is equivalent to
situation that a plurality of aligned small magnets whose poles are
alternately opposite simultaneously move linearly along an aligning
direction. Therefore, the holder magnets 513 magnetically coupled
with the roller magnets 712 also move linearly as the roller
magnets 712 are rotated, resulting in that the first substrate
holder 51 moves linearly as a whole. During this liner movement,
the main pulleys 714 and the sub-pulleys 715,715 shown in FIG. 3
are driven to rotate following the movement.
[0055] In the composition shown in FIG. 1, the vacuum chambers
provided at corners of the first and the second transfer path 1, 2
are the direction-conversion chambers 17, 29 comprising a
direction-conversion mechanism that converts the transfer direction
of the substrate 9 for 90 degrees. Using FIG. 4, a composition of
the direction-conversion mechanism provided in the
direction-conversion chamber 17 is described as an example. FIG. 4
shows a schematic side view of the direction-conversion mechanism
provided in the direction-conversion chamber 17.
[0056] The direction-conversion mechanism shown in FIG. 4 is mainly
composed of a holder 721 holding the linear movement mechanism
including the magnetic-coupling rollers of the same composition as
described (not shown in FIG. 4), and a motor 722 for rotating the
holder 721, thereby rotating the linear movement mechanism as a
whole.
[0057] A drive rod 716 is connected with a shaft of a
magnetic-coupling roller (not shown in FIG. 4) through a motion
transfer mechanism such as a bevel gear. Another bevel gear 723 is
disposed at a rear end of the drive rod 716 as shown in FIG. 4. A
power transmission rod 724 posing vertically is connected with this
bevel gear 723. A bevel gear 725 engaging with the bevel gear 723
disposed at the rear end of drive rod 716 is provided at the top of
the power transmission rod 716. An output shaft of a motor 717 is
connected with a bottom end of the power transmission rod 724.
[0058] On the other hand, the holder 721 composing the
direction-conversion mechanism is a member having a shape of a
column or a cylinder, whose axis is vertical. As shown in FIG. 4,
the holder 721 has a through hole lengthened vertically, through
which the power transmission rod 724 is inserted. Bearings 725 are
provided at a clearance between the inner surface of the through
hole and the power transmission rod 724 so that the power
transmission rod 724 is retained in the through hole while allowing
the rotation of the power transmission rod 724.
[0059] The described holder 721 is placed in a holder cover 726.
The holder cover 726 has a nearly cylindrical shape and a larger
radius than the holder 721. The holder cover 726, which supports
the holder 721, is installed with a bottom wall 727 of the
direction-conversion chambers 17,29. The bottom wall 727 of the
direction-conversion chambers 17,29 has a circular opening with a
size that suits an outer diameter of the holder cover 726. The
holder cover 726 is fitted in this opening. A vacuum seal such as
an O-ring is provided at an interface of the holder cover 726 and
the bottom wall 727.
[0060] Four bearings 729 and a mechanical seal 728 are provided at
a clearance between the holder cover 726 and the holder 721. The
mechanical seal 728 is interposed between the uppermost and next
bearings 729. The mechanical seal 728 is to seal the clearance
between the holder 721 and the holder cover 726 while allowing a
rotation of the holder 721. As the mechanical seal 728, a seal
mechanism using magnetic-fluid is preferably employed.
[0061] A pulley mount 730 is provided at the bottom of the holder
721. A holder pulley 731 is fixed at the bottom of the pulley mount
730. The holder pulley 731 is coaxial with the holder 721. A pulley
732 is provided at a position at the same level as the holder
pulleys 731. An output shaft of a motor 722 is connected with the
pulley 732. There is a belt 733 stretching between the pulley 732
and the side pulleys 731 to connect them. The pulley 731 and the
pulley 732 are timing pulleys and the belt 733 is a timing
belt.
[0062] A frame 734 as shown in FIG. 4 is fixed on an upper surface
of the holder 721. The frame 734 is to retain together the first
substrate holder 51, the magnetic-coupling roller 711 and other
members shown in FIG. 2. As shown in FIG. 4, several supports 735
are provided uprightly on a lower part of the frame 734. The
described main pulleys and the sub-pulleys are supported by the
supports 7.35. A vacuum seal (not shown) is provided between the
frame 734 and the holder 721 to prevent leak of vacuum in the
direction-conversion chamber 17 from the inside of the frame
734.
[0063] An operation of such a direction-conversion mechanism in the
direction-conversion chamber 17 is described as follows.
[0064] To begin with, when the motor 717 is operated, the rotation
motion is transmitted to the magnetic-coupling roller (not shown in
FIG. 4) through the power transmission rod 724 and the drive rod
716, thereby rotating the magnetic-coupling roller. As a result of
this rotation, the first substrate holder 51 moves linearly.
[0065] When the first substrate holder 51 reaches a specific
position in the direction-conversion chamber 17, the motor 722 is
operated. A drive of the motors 722 is transmitted to the pulley
731 via the pulley 732 by the belt 733. As a result, the holder 721
is rotated, thereby rotating the linear transfer mechanism held by
the holder 721 simultaneously. With this rotation, the first
substrate holder 51 is also rotated. When the rotation angle
reaches 90 degrees, the operation of the motor 722 is stopped,
thereby stopping the rotation of the first substrate holder 51. By
this operation, the transfer direction of the first substrate
holder 51 is converted to a direction rotated by 90 degrees.
[0066] Afterwards, receiving a control signal, the linear transfer
mechanism is driven so that the first substrate holder 51 can be
moved along the first transfer path 1 in the direction rotated by
90 degrees to a next vacuum chamber. Therefore, the surface of the
substrate 9 faces to the side of the transfer path 1, even after
the substrate 9 turns a corner of the rectangular first transfer
path 1.
[0067] In the described composition of the direction-conversion
mechanism, the control of the rotation angle such as 90 degrees may
be carried out by control of the motor 722 or by a detector (not
shown) detecting the rotation angle of the holder 721.
[0068] Next are described details on the vacuum chambers of the
first and the second groups.
[0069] First of all, the vacuum chambers of the first group are
described. The first group is composed of a load lock chamber 11 in
which the substrate 9 temporarily stays when it is transferred from
the atmosphere, a pre-heat chamber 12 to which the substrate 9 is
transferred next from the load lock chamber 11, an underlying-film
deposition chamber 13 to which the substrate 9 is transferred next
from the pre-heat chamber 12, a magnetic-film deposition chamber 14
to which the substrate 9 is transferred next to the underlying-film
deposition chamber 13, the overcoat deposition chamber 15 to which
the substrate 9 is transferred next from the magnetic-film
deposition chamber 14, the first transition chamber 16 in which the
substrate 9 temporarily stays when it is transferred to the second
transfer path 2, the direction-conversion chambers 17, and an extra
vacuum chamber 10.
[0070] The loading robot 61 is provided at the outside of the load
lock chamber 11. The loading robots 61 is a robot that takes out
the substrate 9 from a cassette 611 placed at a load station in the
atmosphere, and load it onto the first substrate holder 51.
[0071] The pre-heat chamber 12 is a chamber in which the substrate
9 is heated to release gases existing on or in the substrate 9. The
pre-heat chamber 12 comprises a lamp heater in it so that the
substrate 9 is heated to a specific temperature.
[0072] In the underlying-film deposition chamber 13 and the
magnetic-film deposition chamber 14, a specific thin-film is
deposited by sputtering. As an example, components on the
magnetic-film deposition chamber 14 are described using FIG. 5.
FIG. 5 shows a schematic plane view of the magnetic-film deposition
chamber 14 shown in FIG. 1.
[0073] The magnetic-film deposition chamber 14 comprises a pumping
system 141 that discharge an air in the chamber, a gas-introduction
system 142 that introduces a process gas into the inside of the
chamber, a target 143 whose surface to be sputtered is exposed to
the inside space of the magnetic-film deposition chamber 14, a
sputtering power supply 144 for applying voltage to the target 143
to generate a sputtering discharge, and a magnet assembly 145
provided behind the target 143 for the magnetron sputtering.
[0074] While introducing the process gas such as argon into the
magnetic-film deposition chamber 14 by the gas introduction system
142 and maintaining a specific vacuum pressure by the pumping
system 141, the sputtering power supply 144 is operated.
[0075] As a result, the sputtering discharge is ignited. Particles
released from the target through the sputtering discharge reach the
substrate 9, thereby depositing a specific thin film on the
substrate 9.
[0076] The overcoat deposition chamber 15 comprises a plasma
generation means 150 so that plasma-enhanced chemical vapor
deposition (PE-CVD) is enabled. FIG. 6 is a schematic plane view of
the overcoat deposition chamber 15 shown in FIG. 1. The overcoat
deposition chamber 15 comprises a pumping system 151 for
discharging an air in the chamber. The plasma generation means 150
is mainly composed of a gas-introduction system 152 that introduces
a gas mixture of hydrocarbon such as CH.sub.4 and hydrogen into the
chamber, and a HF power supply 153 for applying HF power to the gas
mixture to form plasma P. Here, frequencies between LF (Low
Frequency) and UHF (Ultra-High Frequency) are defined as HF (High
Efficiency). The hydrocarbon gas decomposes in the plasma P,
thereby depositing a carbon thin-film on the substrate 9. A
self-bias voltage may be given to the substrate 9 by applying a HF
voltage to the substrate 9 via the first substrate holder 51. The
self-bias voltage is a voltage that has a negative direct current
portion and is produced by a mutual reaction of the plasma P and
the HF field.
[0077] In this embodiment, a couple of the underlying-film
deposition chambers 13 and a couple of the magnetic-film deposition
chambers 14 are provided, as shown in FIG. 1. The substrates 9 are
transferred from one underlying-film deposition chamber 13, to the
other underlying-film deposition chamber 13, to one magnetic-film
deposition chamber 14, to the other magnetic-film deposition
chamber 14 in order. In other words, the underlying film is
deposited in a form of a double layer. And, the magnetic film is
deposited on the double-layered underlying film in a form of a
double layer as well. There may be another structure where a layer
made of the underlying film and the magnetic film is doubled.
Showing examples of the films, a Cr film is deposited as the
underlying film, and a CoCrTa film is deposited as the magnetic
film. As shown in FIG. 1, a couple of the overcoat deposition
chambers 15 are provided. In the first overcoat deposition chamber
15, the overcoat is deposited at half of required thickness, and in
the second overcoat deposition chamber 15 the overcoat with the
rest half thickness is deposited.
[0078] Next are described details on the vacuum chambers of the
second group.
[0079] The chambers of the second group is composed of the second
transition chamber 21 in which the substrate 9 temporarily stays
after the substrate 9 is transferred through the first transfer
path 1 and the third transfer path 3, the first cleaning chamber 22
in which contaminants are removed from the substrates 9 by a plasma
ashing method, the second cleaning chamber 23 in which contaminants
are removed from the substrates 9 by a gas blowing method, a
burnishing chamber 24 in which protrusions on the substrates 9 are
removed, a lubricant-layer preparation chamber 25 in which the
lubricant layer is prepared on the substrates 9, the
post-preparation treatment chamber 26 in which the treatment is
carried out after the lubricant-layer preparation, the cooling
chamber 27, an extra chamber 20, an unload lock chamber 28 in which
the substrate 9 temporarily stays when the substrate 9 is
transferred to the atmosphere, and the direction-conversion
chambers 29.
[0080] One of points that characterize this embodiment is the first
cleaning chamber 22. Components on the first cleaning chamber 22
are described using FIG. 7. FIG. 7 shows a schematic plane view of
the first cleaning chamber 22 shown in FIG. 1.
[0081] In the first cleaning chamber 22, the contaminants are ashed
by oxygen plasma. The components on the first cleaning chamber 22
are almost the same as on the overcoat deposition chamber 15 shown
in FIG. 6, except that a gas-introduction system 222 introduces an
oxygen gas. Concretely, the first cleaning chamber 22 comprises a
couple of HF electrodes 223 located at both sides of the substrates
9 and a HF power source 224 that applies the HF voltage to the
electrodes 223 to generate the plasma P.
[0082] The HF electrodes 223 are hollow and have a number of gas
effusion holes on a surface facing to the substrates 9. The
gas-introduction system 222 introduces oxygen gas into the first
cleaning chamber 22 through the inside of the HF electrode 223. The
gas-introduction system 222 may mix a buffer gas or a gas for
improving discharge characteristics with the oxygen gas.
[0083] Contaminants formed of carbon or hydrocarbon sometimes
adhere to the surface of the overcoat deposited on the substrates
9. Adhesion of the contaminants is caused from factors as described
next. The adhesion of carbon mainly results from suspended
particles in the overcoat deposition chamber 15. In the overcoat
deposition chamber 15, thin films, i.e. carbon films, are deposited
not only on the surfaces of the substrates 9 but also on exposed
surfaces of members in the overcoat deposition chamber 15 and a
surface of the first substrate holder 51. These thin-films may be
peeled off by internal stress or another factors, when those grow
to be thick films. The peeled thin film produces the suspended
particles in the overcoat deposition chamber 15. If the particles
adhere to the substrates 9, the wettability, i.e. a degree of
contact, of the lubricant may deteriorate in the lubricant-layer
preparation. Otherwise, abnormal film growth may take place to form
minute protrusions on the substrates 9 in the overcoat
deposition.
[0084] The adhesion of hydrocarbon is mainly caused under influence
of residual gases in the overcoat deposition chamber 15. Though the
overcoat is deposited utilizing decomposition of the hydrocarbon
gas in the plasma, non-decomposed hydrocarbon gases still reside in
the overcoat deposition chamber 15. These residual gases may adhere
to the substrates 9. When adhesion of the residual gases is
accumulated, the residual gases may grow to be molecules or
particles of some size on the substrate 9. If such molecules or
particles are produced on the surface of the substrate 9,
wettability of the lubricant may deteriorate, or characteristics of
the lubricant layer may be affected.
[0085] When the substrate 9 on which such contaminants exist is
exposed to the oxygen plasma, the carbon and hydrocarbon are
rapidly oxidized, i.e. burnt, thereby becoming volatile substances
such as carbon dioxide and water. This oxidation is caused by
species produced in the oxygen plasma such as oxygen ions,
monoatomic oxygen molecules (O) that are active, and activated
oxygen molecules (O2*). Those volatile substances are pumped out by
the pumping system 221 of the first cleaning chamber 22. By
carrying out such the ashing, it is enabled to suppress the
problems that adhesion strength of the lubricant may decrease, and
that a magnetic head may be obstructed by the minute protrusions on
the surface of the magnetic recording disk.
[0086] On condition of the ashing, prudent examination is required.
This is because excessive ashing may lead to eroding the surface of
the overcoat. TABLE 1 shows a preferred example of conditions of
the ashing on a substrate of 3.5-inch size.
1TABLE 1 Preferred Ashing Condition Preferred Condition range or
value Pressure in the chamber 22 1-2 (Pa) Flow rate of oxygen gas
100 (SCCM) HF power 50 (W) Frequency 13.56 (MHz)
[0087] In TABLE 1, "SCCM" means a gas flow rate converted at
0.degree. C. and 1 atm, standing for "Standard Cubic Centimeter per
Minute". When the ashing is carried out on the above condition, the
contaminants can be removed within 0.3-2.0 seconds, while
preventing the problem of the overcoat erosion. If the ashing is
carried out with HF power over 50W, or if the ashing is carried out
over 2.0 seconds, the overcoat might be eroded. Therefore, it is
preferable that the ashing is carried out with HF power of 50W or
less and for 2.0 seconds or less.
[0088] Next are described components on the second cleaning chamber
23. FIG. 8 shows a schematic plane view of the second cleaning
chamber 23 shown in FIG. 1.
[0089] The second cleaning chamber 23 comprises a pumping system
231 that discharges an air in the chamber, and a couple of gas
introduction tubes 233 having a nozzle 232 that eject a gas toward
the substrates 9. Each nozzle 232 is a circular disk and parallel
to the substrates 9. Each nozzle 232 has a diameter little larger
than that of the substrate 9. Many gas ejection holes are provided
on each nozzle 232 with an equal interval.
[0090] The gas is ejected from each nozzle 232 onto of the
substrates 9 so that the contaminants adhering on the substrates 9
can be blown away. A pressure in the second cleaning chamber 23 is
about 1.times.10.sup.-4-1.times.10.sup.-5 Pa, and an ejection
pressure of the gas at the substrates 9 is about 100 Pa. For this
gas, an inert gas such as argon or nitrogen is adopted. A filter
that removes the contaminants is preferably provided on a gas
introduction line (not shown) connected with the gas introduction
tube 233.
[0091] It may be possible to carry out the described gas-blow
cleaning at the atmosphere. However, the gas-blow cleaning in the
atmosphere has higher probability that the contaminants still
remain after the cleaning than the cleaning in vacuum, because
cleanliness of ambience is worse.
[0092] It can be adopted to clean the substrate 9 by extra-fine
fibers instead of the cleaning by the plasma or the gas blow.
Specifically, the substrate 9 is rubbed with a fabric made of
extra-fine fibers of about 0.06 denier. This fabric is similar to
one that is on sale as a glass wiper.
[0093] Next is described about the burnishing chamber 24.
[0094] FIG. 9 shows a schematic side view of the burnishing chamber
24 shown in FIG. 1. As shown in FIG. 9, the burnishing chamber 24
comprises a pumping system 241 that discharges an air in the
chamber, a rotation mechanisms 8 that holds and rotates the
substrate 9 around a rotation axis corresponding to the center of
the substrate 9, and a burnishing tape 242 that is pressed on the
substrate 9 being rotated by the rotation mechanism 8.
[0095] A detail of the rotation mechanisms 8 is described using
FIG. 10. FIG. 10 shows a schematic cross-sectional view of the
rotation mechanism 8 shown in FIG. 9. As shown in FIG. 10, the
rotation mechanism 8 is mainly composed of a back-and-fore drive
shaft 81 elongated horizontally, a cylindrical rotation drive shaft
82 provided coaxially with the back-and-fore drive shaft 81, the
first back-and-fore drive source 83 that drives the back-and-fore
drive shaft 81, a rotation drive source 84 that rotates the
rotation shaft 82, and the second back-and-fore drive source 85
which moves backward or forward the back-and-fore drive shaft 81
and the rotation drive shaft 82 together.
[0096] At an end of the back-and-fore drive shaft 81, a drive head
86 is provided. The drive head 86 is formed of a disk portion 861
that is slightly smaller than a center opening of the substrate 9,
and a taper portion 862 with a shape of circular cone coaxial with
the back-and-fore drive shaft 81.
[0097] Contact blades 821 are provided at an end of the rotation
drive shaft 82. The contact blades 821 are members that contact an
inner edge of the center opening of the substrate 9, when the
substrate 9 is held by the rotation mechanism 8. FIG. 11 shows a
front view explaining locations of the contact blades 821 shown in
FIG. 10. As shown in FIG. 11, three contact blades 821 are provided
at every 120 degrees on a circumference coaxial with the
back-and-fore drive shaft 81. As shown in FIG. 10, a
cross-sectional shape of each contact blade 821 is like a curved
concave or a "V"-shape.
[0098] As shown in FIG. 10, driven blades 822 contacting a tapered
surface of the taper portion 862 are provided. Connection plates
824 are provided. The connection plates 824 connect each driven
blade 822 and each contact blade 821 respectively. Projections are
provided on an end of the rotation shaft 82. Spring members 823
such as coil springs connecting each protrusion and each driven
blade 22 are provided. Each driven blade 822 is fixed with each
projection through each spring member 823. The contact blades 821
are located outside the projections. The contact blades 821 can
slide on the end of the rotation shaft 82.
[0099] The back-and-fore drive shaft 81 is connected with the first
back-and-fore drive source 83 through a joint mechanism 811 capable
of disconnection. The first back-and-fore drive source 83 is a
linear motion source that is a combination of a servomotor and a
precise screw, or a linear actuator such as an air cylinder. The
rotation drive source 84 is a motor connected with the outer
surface of the rotation drive shaft 82 through gears. The second
drive source 85 moves the frame 851 backward or forward, on which
the back-and-fore drive shaft 81, the rotation driving shaft 82,
the first back-and-fore drive source 83 are mounted, thereby moving
them simultaneously as a whole. The rotation drive shaft 82
penetrates airtightly a wall of the burnishing chamber 24 with a
vacuum seal such as a mechanical seal.
[0100] A lever (not shown) linked to the described rotation
mechanism 8 is provided in the burnishing chamber 23. This lever
has the same function as the described lever 60 provided in each
robot 61, 62, 63.
[0101] On the other hand, a storing roller 243 for storing the
burnishing tape 242 is provided in the burnishing chamber 24. The
burnishing tape 242 is rolled up around the storing roller 243 in
advance. The burnishing tape 242 is used for the burnishing, being
rolled out from the storing roller 243. A retrieval roller 244 that
retrieves a used portion of the burnishing tape 242 is provided in
the burnishing chamber 24. The retrieval roller 244 is rotated by a
vacuum motor (a motor operatable in a vacuum environment) 245 to
retrieve the used portion of the burnishing tape 242. During this
rotation for the retrieval, the storing roller 243 is forced to
rotate, thereby drawing out a virgin portion of the burnishing tape
242.
[0102] A pressure member 247 that presses the burnishing tape 242
against the substrate 9 is provided. A drive mechanism 0.87 is also
provided in the pressure member 247. FIG. 12 shows a schematic side
view of the drive mechanism 87 that drives the pressure member 247
shown in FIG. 9.
[0103] As shown in FIG. 12, the drive mechanism is mainly composed
of a drive shaft 871, a torque motor 872 that drives the drive
shaft 871, a linear drive source 873 for moving backward or forward
the drive shaft 871 and the torque motor 872 together. The pressure
member 247 is fixed at an end of the drive shaft 871. The torque
motor moves the drive shaft 871 forward so that the pressure member
247 is pressed against the substrate 9.
[0104] A precise screw, or a ball thread, 874 is jointed with an
output shaft of the torque motor 872. A rear portion of the drive
shaft 871 is hollow. An inner surface of this portion is screwed,
with which the precise screw 874 is engaged. A rotation of the
drive shaft 871 is restrained by a restraint member (not shown). As
the linear drive source 873, a combination of a motor and a precise
screw, or an air cylinder is adopted. The drive shaft 871
airtightly penetrates a wall of the burnishing chamber 24 with a
vacuum seal such as a mechanical seal. As understood from FIG. 9,
the burnishing tape 242, the storing roller 243, the retrieval
roller 244, the vacuum motor 245, the pressure member 247 and the
drive mechanism are provided at both sides of a location of the
substrate 9, respectively.
[0105] A width of a pressing area on the pressure member 247 is
nearly the same as a difference between a radius of the center
opening and a radius of the substrate 9. The width of the pressing
area may be shortened, if the substrate 9 moves along a radius
direction relative to the burnishing tape 243 and the pressure
member 247 while the substrate 9 is rotated.
[0106] An operation of the burnishing chamber 24 is described as
follows.
[0107] The burnishing chamber 24 is pumped by the pumping system
241 in advance. The second back-and-fore drive source 85 moves the
back-and-fore drive shaft 81 and the rotation shaft 82 to a standby
position in advance. In a state that a pressure in the burnishing
chamber 24 is maintained at a specific vacuum pressure, the second
substrate holder 52 holding the substrates 9 is moved into the
burnishing chamber 24. The second substrate holder 52 is stopped at
a position where the center of one of the substrates 9 corresponds
to the center axis of the back-and-fore drive shaft 81 shown in
FIG. 9 and FIG. 10.
[0108] Next, the second back-and-fore drive source 85 is operated
to move the back-and-fore drive shaft 81 and the rotation drive
shaft 82 forward simultaneously. The back-and-fore drive shaft 81
and the rotation drive shaft 82 are stopped at a position where the
drive head 86 is projected through the opening of the substrate 9
and the contact blades 821 are located at the same vertical plane
as the substrate 9, as shown in FIG. 10.
[0109] In this state, the first back-and-fore drive source 83 is
operated to move the back-and-fore drive shaft 81 backward. As the
back-and-fore drive shaft 81 is moved backward, the driven blades
822 contacting the tapered surface of the taper portion 862 shift
outward against elasticity of the spring member 823. Concurrently,
each contact blade 821 also shifts outward, thereby contacting the
inner edge of the center opening of the substrate 9. The first
back-and-fore drive source 83 applies adequate force that works so
as to move the back-and-fore drive shaft 81 backward. Therefore,
each contact blade 821 is pressed onto the inner edge of the center
opening of the substrate 9 adequately. With this operation, the
substrate 9 is held by the rotation mechanism 8.
[0110] In this state, the lever (not shown in FIG. 9) is driven to
expand each of the spring of the spring bands (not shown in FIG. 9)
outwardly. As a result, the substrate 9 is held only by the
rotation mechanism 8.
[0111] Next, the rotation drive source 84 of the rotation mechanism
8 is operated to rotate the back-and-fore drive shaft 81 and the
rotation drive shaft 82 together. With the rotations of the
back-and-fore drive shaft 81 and the rotation drive shaft 82, the
substrate 9 held by the contact blades 821 is also rotated. During
this rotation, the joint mechanism 811 disconnects the
back-and-fore drive shaft 81 from the first back-and-fore drive
source 83.
[0112] While the substrate 9 is rotated, the drive mechanism 87 at
both sides of the substrates is operated. The pressure members 247
at both sides are moved to a specific fore position by the linear
drive source 873. This fore position is slightly back from a
position at which the pressure member 247 just presses the
burnishing tape against the substrate 9. Next, the torque motor 872
is operated to move the pressure member 247 slightly forward. As a
result, the pressure member 247 presses the burnishing tape 242
against the substrate 9. A generated torque is adjusted to control
a press pressure of the burnishing tape 242 at a specific
value.
[0113] The substrate 9 is rubbed with the pressed burnishing tape
242, resulting in that the protrusions on the substrate 9 are
removed. In addition to the protrusion removal, the contaminations
are sometimes removed if those have adhered to the substrate 9. The
burnishing tape 242 is, for example, a tape made of
polyethylene-terephthalate or polyamide, on which many abrasive
grains such as alumina grains or silicon carbide gains are fixed. A
rotation speed of the substrate 9 may be 100-4000 rpm.
[0114] Prudent examination is required for determining a pressing
force of the pressure member 247. When the burnishing by the
burnishing tape 242 is carried out in vacuum, a friction force
between the burnishing tape 242 and the substrate 9 is higher than
that in the atmosphere. Therefore, if the burnishing tape is
pressed with the same force as in the case of the burnishing in the
atmosphere, the substrate 9 is scraped excessively. As a result,
not only protrusion can be removed, but also thickness of the
overcoat might be made thinner. For example, in the case of the
burnishing at about 1.0.times.10.sup.-2-100 Pa, a pressure force is
preferably 9.8-588 mN.
[0115] There may be a case that the burnishing is carried out
without moving the substrate 9 but with moving the burnishing tape
242, i.e. with retrieving the burnishing tape, while the burnishing
tape 242 is pressed against the substrate 9. In this case, the
pressure member 247 is modified into a member that corresponds with
a following roller.
[0116] After carrying out the described burnishing on the whole
surface of the substrate 9, the drive mechanism 8 moves the
pressure member 247 to a specific back position, and the operation
of the rotation drive source 84 is stopped. Next, the lever
releases the spring bands to make the second substrate holder 52
hold the substrate 9 by the pallets again. After the first
back-and-fore drive source 83 and the back-and-fore drive shaft 81
are jointed by the joint mechanism 811 again, the first
back-and-fore drive source 83 moves the back-and-fore drive shaft
81 forward by a specific distance. As a result, the contact blades
821 are moved inside by elasticity of the spring member 823, and
the rotation mechanism 8 releases the substrate 9. Then, the second
back-and-fore drive source 85 moves the back-and-fore drive shaft
81 and the rotation drive shaft 82 backward together to the initial
stand-by position.
[0117] Next, the second substrate holder 52 is moved to a position
where the center of the other substrate 9 is just on an axis of the
back-and-fore drive shaft 81. Then, the burnishing is carried out
on the other substrate 9 as well by repeating the same operation as
described. As shown in FIG. 1, a couple of the burnishing chambers
24 are provided interposing the lubricant-layer preparation chamber
25. Therefore, the burnishing is carried out before and after the
lubricant-layer preparation.
[0118] Next is described about the lubricant-layer preparation
chamber 25.
[0119] FIG. 13 shows a schematic side view of the lubricant-layer
preparation chamber 25 shown in FIG. 1. The lubricant-layer
preparation chamber 25 is a chamber in which the lubricant layer is
prepared on the substrate 9 in vacuum. The lubricant layer is
prepared by the vacuum vapor deposition method in the
lubricant-layer preparation chamber 25.
[0120] As shown in FIG. 13, the lubricant-layer preparation chamber
25 comprises a pumping system that discharges an air in the
chamber, a couple of pots 252 in which lubricant is stored, a
heater 253 for evaporating the lubricant in each pot 252, and a
rotation mechanism 8 for rotating the substrate 9 during the
deposition.
[0121] The lubricant is stored in the pots 252 without diluting
with any solvent. The heater 253 is a kind of resistance heaters.
Other than the resistance heaters, an electron-beam irradiation
heater or an HF induction heater may be employed as the heater 253.
A shutter is provided over each pot 252 if necessary.
[0122] The rotation mechanism 8 may be the same as one provided in
the burnishing chamber 24 shown in FIG. 9. In this embodiment, a
couple of the rotation mechanisms 8 are provided so that two
substrates 9 can be rotated simultaneously.
[0123] An operation of the lubricant-layer preparation chamber 25
shown in FIG. 13 is described as follows.
[0124] The lubricant-layer preparation chamber 25 is pumped by the
pumping system 251 in advance. In a state that a pressure in the
burnishing chamber 25 is maintained at a specific vacuum pressure,
the second substrate holder 52 holding the substrates 9 is moved
into the lubricant-layer preparation chamber 25 and is stopped.
Each rotation mechanism 8 holds and rotates each substrate 9,
respectively. Simultaneously, each heater 253 heats the lubricant
in each pot 252. The lubricant is evaporated by heating, thereby
depositing a lubricant film as the lubricant layer on each
substrate 9. The lubricant layer is prepared on two substrates 9
simultaneously. A principal component of the lubricant may be PEPE.
A molecular weight of the lubricant may be 2000-4000. As
commercially available lubricant of this kind, there are ZDOL200
and ZDOL4000 (production names) of AUSMONT Corporation.
[0125] A heating temperature by the heater may be 50-310.degree. C.
A pressure in the lubricant-layer preparation chamber 25 may be
about 1.0.times.100.sup.-2-10 Pa. When the deposition is carried
out under such conditions, the lubricant film of 1-2 nm in
thickness is deposited within 3-5 seconds. A rotation speed is
lower than that in the described burnishing. Specifically, it may
be about 5-500 rpm.
[0126] After carrying out the lubricant-layer preparation, the
operations of the heater 253 and the rotation mechanisms 8 are
stopped. The substrates 9 are returned to the second substrate
holder 52. After the lubricant-layer preparation chamber 25 is
pumped again, the second substrate holder 52 is moved to the next
post-preparation treatment chamber 26.
[0127] Next are described about the post-preparation treatment
chamber 26 and the cooling chamber 27. FIG. 14 shows a schematic
side view of the post-preparation treatment chamber as shown in
FIG. 1.
[0128] The optimum bonded ratio is supposed 20-30% as described. In
this embodiment, a bonded ratio within this range is accomplished
by heating the substrates 9 in the post-preparation treatment
chamber 26, and by optimizing a heating temperature and a heating
time. Specifically, the above bonded ratio is accomplished by
maintaining a temperature of the substrate 9 at 30-150.degree. C.
for 3-5 seconds.
[0129] As shown in FIG. 14, an infrared (IR) lamp 261 is provided
at both sides of the substrate 9 held with the second substrate
holder 52 in the post-preparation treatment chamber 26. A pumping
system 262 is provided in the post-preparation treatment chamber
26. The pumping system 262 pumps the post-preparation treatment
chamber 26 to maintain a pressure at
1.times.10.sup.-4-1.times.10.sup.-5 Pa during the post-preparation
treatment. Although the vacuum is not an indispensable condition
for the post-preparation treatment because this is the step after
the lubricant preparation, it is enabled to prevent the
contaminants from being adsorbed on a hot surface of the heated
lubricant layer by carrying out the post-preparation treatment in
vacuum.
[0130] Instead of the heating, the post-preparation treatment may
be carried out by irradiation. For example, in a case that the
lubricant is capable of photo polymerization, a degree of the
polymerization of the lubricant can be controlled by irradiating
light such as ultraviolet ray. By this control, it is possible to
adjust an adhesive strength and surface lubricity of the lubricant
layer. If this method is employed, an ultraviolet (UV) lamp may be
used instead of the IR lamp 261.
[0131] The cooling chamber 27 is one for cooling the substrate 9
after the treatment so that the unloading robot 62 can easily
handle the substrate 9 in the unload lock chamber 28. In the
cooling chamber 27, a cooling gas such as hydrogen or helium is
blown on the substrate 9, thereby cooling it down at about
100.degree. C. or below. The cooling system disclosed in Japanese
Patent Publication No. 11-203734 is preferably applied to this
cooling chamber 27. The unloading robot 62 provided in the unload
lock chamber 28 takes out the substrate 9 from the second substrate
holder 52, and transfer it to an unloading cassette 621 placed in
the atmosphere.
[0132] Next is described a whole operation of the apparatus of this
embodiment as follows. The following is a description of a
manufacturing method according to an embodiment of the invention
too.
[0133] Two of the substrates 9 are transferred from the loading
cassette 611 in the atmosphere to the load lock chamber 11 by the
loading robot 61 piece by piece, and are loaded on the first
substrate holder 51. The first substrate holder 51 is moved to the
pre-heat chamber 12. The substrates 9 are pre-heated in the
pre-heat chamber 12. After the pre-heating, the first substrate
holder 51 is moved to the underlying-film deposition chamber 13,
the magnetic-film deposition chamber 14, and the overcoat
deposition chamber 15 in order, thereby accumulatively depositing
the underling film, the magnetic film and the overcoat on the
substrates 9.
[0134] The substrates 9 are unloaded from the first substrate
holder 51 by the shifting robot 63 in the first transition chamber
16, and are loaded on the second substrate holder 52 on standby in
the second transition chamber 21. The first substrate holder 51
without the substrates 9 is returned to the load lock chamber 11,
in which next two substrates 9 are loaded.
[0135] On the other hand, the second substrate holder 52 holding
the substrates 9 is moved to the first cleaning chamber 22, the
second cleaning chamber 23, the burnishing chamber 24 and the
lubricant-layer preparation chamber 25 in order, thereby preparing
the lubricant layer on the overcoat. Consequently, the second
substrate holder 52 is moved to the post-preparation treatment
chamber 26 and the cooling chamber in order, thereby carrying out
the treatment and the cooling of the substrates 9. When the second
substrate holder 52 reaches the unload lock chamber 28, the
substrates 9 are unloaded from the second substrate holder 52 and
transferred out to the unloading cassette 621 at the atmosphere.
The second substrate holder 52 without the substrates 9 is moved to
the second transition chamber 21 for holding next two substrates 9.
The second substrate holder 52 holding the next two substrates 9 is
circulated along the second transfer path 2. During this operation,
in each chamber 10-17, 20-29, the first substrate holder 51 or the
second substrate holder 52 is located. Each substrate holder 51,52
is moved to the next chamber 10-17, 20-29 at every tact time.
[0136] The described apparatus of this embodiment has advantages as
follows.
[0137] First of all, because it is possible to carry out the steps
from the underlying-film deposition to the lubricant-layer
preparation with the only one apparatus, costs such as an equipment
cost for manufacture and a labor cost for operation are reduced. An
unmanned operation is possible while all the substrates 9 in the
loading cassette 611 are processed and unloaded to the unloading
cassette 621. Therefore, the productivity is improved because an
unmanned operation time is extended.
[0138] In addition, because the steps after the overcoat deposition
to the lubricant-layer preparation are carried out without breaking
vacuum, the incorporation or the adhesion of the contaminants with
the overcoat and the lubricant layer is prevented. Accordingly, the
apparatus of this embodiment can suppress the problems that: the
recording layer may be contaminated; the adhesive strength of the
lubricant layer may decrease; the thickness of the lubricant-layer
may be made out of uniform; and control accuracy of the
bonded-ratio of lubricant-layer may decrease. Therefore, the
apparatus of this embodiment is much suitable for manufacture of
the magnetic recording disks, where the spacing is decreasing.
[0139] In addition, because the contaminants on the substrate 9 are
removed by the plasma-enhanced ashing method and the gas blow
method, the above advantages are made higher. The plasma-enhanced
ashing method is effective mainly for removal of the organic
contaminants. The gas-blowing method is effective mainly for
removal of the inorganic contaminants such as metal or glass. After
the cleanings in the first cleaning chamber 22 and the second
cleaning chamber 23, the substrate 9 is transferred to the
lubricant-layer preparation chamber 25 without being exposed to the
atmosphere. The lubricant layer is prepared on the surface of the
substrate 9 that remains cleaned, because the surface is not
contaminated by the atmosphere. Therefore, the above advantages are
also made higher from this point.
[0140] In addition, because the burnishing is carried out in
vacuum, the contaminants in the atmosphere never adhere to the
substrate 9 during the burnishing. From this point, the problems
caused by the contaminants are prevented as well. Because the
substrate 9 is transferred to the post-preparation treatment
chamber 26 without being exposed to the atmosphere after the
lubricant-layer deposition, this advantage is also made higher.
[0141] The point that the lubricant is used without diluting with
solvent brings following advantages.
[0142] As solvent for the lubricant, flon (chloro-fluoro-carbon)
conventionally has been used because the lubricant is fluoride.
However, considering a problem of the ozone layer destruction, use
of flon-alternative solvent such as perfluorocarbon has become a
major issue. Still, even the flon-alternative solvent is sometimes
questioned because that is regarded as a material causing the
global warming.
[0143] Another problem with respect to the use of solvent is
contamination of the lubricant layer. Diluted lubricant easily
contains contaminants, resulting in that the contaminants are
incorporated with the lubricant layer. The contaminants in the
lubricant layer may cause many kinds of problems that: the magnetic
head is corroded by ionized contaminants; the magnetic head is
mechanically damaged by the protrusions formed on the surface of
the lubricant layer; the magnetic head is chucked on the surface of
the magnetic recording disk because the lubricity decreases.
Contrarily, the method and the apparatus of the embodiments are
free from these problems because of no use of the solvent.
[0144] Nevertheless, a small amount of solvent is occasionally used
on such purpose as to make it easier to deal with the lubricant. As
solvent, perfluoroalkyl, for example, HFE7300 or HFE7100 of 3M
Corporation may be used. A quantity of the solvent is one volume
percentage or below against the lubricant.
[0145] Next is described a magnetic disk manufacturing apparatus of
the second embodiment of the invention.
[0146] FIG. 15 shows a main part of the magnetic recording disk
manufacturing apparatus of the second embodiment. The apparatus
shown in FIG. 15 is different from the described first embodiment
in the composition of the plasma-enhanced ashing to clean the
substrate 9. Concretely, in the embodiment shown in FIG. 15, the
ashing is carried out in the overcoat deposition chamber 15. FIG.
15 shows components on the overcoat deposition chamber 15.
[0147] The components on the overcoat deposition chamber 15 are
nearly the same as those in FIG. 6, except the gas-introduction
system 152. The gas-introduction 152 shown in FIG. 15 can introduce
a gas mixture of carbon hydride and hydrogen, or an oxygen gas
selectively to the overcoat chamber 15.
[0148] In FIG. 15, when an overcoat is deposited, a gas mixture of
hydrocarbon and hydrogen is introduced. After the overcoat
deposition, without moving the first substrate holder 51, the
overcoat chamber 15 is pumped by the pumping system down to about
5.times.10.sup.-2 Pa. Then, the introduced gas is switched to
oxygen by opening and closing the valves 154. The ashing is carried
out by the oxygen plasma in the same way as the described.
[0149] The embodiment shown in FIG. 15 has an advantage that it is
enabled to remove the contaminants not only on the substrate 9 but
also on the first substrate holder 51. If the contaminants remain
on the first substrate holder 51, the contaminants may adhere to
the next substrate 9 held by the first substrate holder next. The
apparatus of this embodiment has an effect that the adhesion of the
contaminants via the first substrate holder 51 is prevented in
addition to the adhesion directly to the substrate 9. Moreover, it
also possible to remove the contaminants adhering to exposed
surfaces of the components in the overcoat chamber 15.
[0150] Next is described a magnetic disk manufacturing apparatus of
the third embodiment of the invention. FIG. 16 shows a main part of
the magnetic recording disk manufacturing apparatus of the third
embodiment of the invention. The apparatus of the third embodiment
has the feature that the third cleaning chamber 200 for cleaning
the substrate 9 is added. The third cleaning chamber 200, for
example, may be interposed between the second cleaning chamber 23
and the burnishing chamber 24 in the layout shown in FIG. 1. FIG.
16 shows a schematic side view of the third cleaning chamber
200.
[0151] In the third cleaning chamber 200 shown in FIG. 16, the
substrate 9 is cleaned by laser irradiation. Concretely, the third
cleaning chamber 200 comprises a laser oscillator 201, and an
introduction window 202 for introducing laser beam into the
chamber. The introduction window 202 is mounted airtightly shutting
an opening formed on a wall of the third cleaning chamber 200.
[0152] The surface cleaning by laser irradiation is mainly
conducted by ablation. When the laser beam is irradiated on the
contaminants adhering to the substrate 9, the contaminants are
rapidly decomposed by energy of the laser beam. The third cleaning
chamber 200 comprises a pumping system 203 so that the laser
irradiation cleaning can be carried out in vacuum.
[0153] TABLE 2 shows an example of condition of the cleaning by
laser irradiation.
2TABLE 2 Preferred Condition of the Laser Irradiation Cleaning
Condition Preferred range or value Laser Excimer laser Wavelength
248 nm Irradiation energy density 200 mJ/cm.sup.2 or below
Irradiation type Pulse (1-100 Hz) The number of pulses 100 or
below
[0154] If an irradiation energy density exceeds 200 mJ/cm2, there
arises a possibility to erode the overcoat on the substrate 9. To
carry out the cleaning without eroding the overcoat, a lower energy
density, a lower frequency of the pulses or a smaller number of the
pulses may be adopted. It is preferable to scan the laser beam in a
radius direction of the substrate 9 while the substrate 9 is
rotated so that the laser beam can be irradiated uniformly on the
whole surface of the substrate 9. For this rotation, the same
rotation mechanism as in the described embodiment may be
employed.
[0155] Next is described a magnetic disk manufacturing apparatus of
the fourth embodiment of the invention. FIG. 17 shows a main part
of the magnetic recording disk manufacturing apparatus of the
fourth embodiment of the invention. A point characterizing this
embodiment is that the burnishing and the lubricant-layer
preparation are carried out in the same chamber. In other words, a
burnishing-preparation chamber 210 is provided instead of the
burnishing chamber 25 and the lubricant-layer preparation chamber
26 in the first embodiment.
[0156] FIG. 17 shows a schematic side view of the
burnishing-preparation chamber 210. The burnishing-preparation
chamber 210 comprises a pumping system 211 that discharges an air
in the chamber, a rotation mechanism 8 that holds and rotates the
substrate 9 around the axis coaxial with the substrate 9, a
burnishing tape that is pressed against the substrate 9 being
rotated by the rotation mechanism 8, and a lubricant coater 213
that coats lubricant on the substrate 9 simultaneously with the
burnishing by a burnishing tape 212.
[0157] Description about the rotation mechanism 8 and the
burnishing tape 212 are omitted because those are the same as in
the described first embodiment. The lubricant coater 213 is mainly
composed of an ejector 214 ejecting the lubricant from a tip
thereof, a feeding tube 215 connected with the ejector 214, and a
pump (not shown) that feeds the lubricant from a lubricant storing
vessel (not shown) to the ejector 214 through the feeding tube 215.
The lubricant coater 213 is provided at each side of the substrate
location.
[0158] An operation of the burnishing-preparation chamber 210 is
described.
[0159] In a state that the burnishing-preparation chamber 210 is
pumped to obtain a specific vacuum pressure, the second substrate
holder 52 holding the substrates 9 is moved into the
burnishing-preparation chamber 210 and is stopped at a specific
position. Then, the rotation mechanism 8 holds one of the
substrates 9 and rotates it. During this rotation, the pressure
members 247 at both sides of the substrate 9 are displaced toward
the substrate 9 by a drive source (not shown), thereby pressing the
burnishing tapes 212 against the substrate 9. As a result, the
protrusions existing on the substrate 9 are removed.
[0160] Simultaneously, the lubricant coater 213 is operated. The
lubricant is fed with the ejectors 214 by the pump through the
feeding tubes 215. The lubricant is ejected from the ejectors 214
and poured onto the burnishing tapes 212. The lubricant poured on
the burnishing tapes 212 is moved as the burnishing tapes 212 are
moved. When the lubricant reaches a place where the burnishing
tapes 212 are pressed against the substrate 9, the lubricant is
thinly extended out between the burnishing tape 212 and the
substrate 9. The extended lubricant adheres to the substrate 9.
Thus, the lubricant is coated on the substrate 9.
[0161] The lubricant in this embodiment may be the same as in the
described embodiment, whose main component is PEPE. The use of a
small amount of the solvent is allowed as described. A space
pressure in the burnishing-preparation chamber 210 and a pressure
strength by the pressure members 247 may be the same as those in
the described embodiment as well.
[0162] After the burnishing and the lubricant coating are
simultaneously carried out on the whole surfaces of the substrate
9, the pressure members 247 are moved backward and the rotation by
the rotation mechanism 8 is stopped. The second substrate holder 52
is moved to a position where the rotation mechanism 8 can hold the
other substrate 9. As the rotation mechanism 8 rotates the other
substrate 9, the burnishing and the lubricant coating are
simultaneously carried out on the whole surfaces of the other
substrate 9. Operations of the components except the
burnishing-preparation chamber 210 are the same as those of the
described first embodiment.
[0163] As understood from the above description, productivity in
this embodiment is enhanced because the burnishing and the
lubricant-layer preparation are simultaneously carried out in the
burnishing-preparation chamber 210. Here, "simultaneously" includes
the case that the burnishing and the lubricant-layer preparation
are carried out literally at the same time, and the case that the
burnishing and the lubricant-layer preparation are carried out
roughly at the same time, exactly not the same time. The apparatus
of this embodiment also has an advantage that the contaminants in
the atmosphere cannot be incorporated with the lubricant layer
because the burnishing and the lubricant-layer preparation are
carried out in vacuum. Therefore, the apparatus contributes to
manufacture of high-quality magnetic recording disks. The advantage
that productivity is enhanced is still the same even when those are
carried out in the atmosphere.
[0164] Carrying out the burnishing in vacuum and carrying out the
lubricant-layer preparation in vacuum are closely related to each
other. Though carrying out the burnishing in vacuum is much
effective for the reduction of the contaminants, the burnishing
possibly might be excessive because a friction force between the
burnishing tape 212 and the substrate 9 is higher than that in the
atmosphere. "Excessive" means a situation that not only the
protrusions are removed, but the deposited overcoat is also scraped
off. Contrarily, the raw lubricant generally has a high viscosity.
If the lubricant may be diluted with the solvent, the coating can
be made easier. However, the use of the solvent brings the
described problems.
[0165] This embodiment has an advantage of solving these
conflicting problems at once, that is, a `killing two birds with
one stone` solution. When the lubricant is coated on the substrate
9 via the burnishing tape 212, the lubricant coating is made easier
even if a viscosity of the lubricant is high, in addition to that
the excessive burnishing is prevented by the lubricant inserted
between the burnishing tape 212 and the substrate 9.
[0166] Though the lubricant-layer preparation is carried out by
pouring the lubricant on the burnishing tape 212 in this
embodiment, the vapor deposition as in the first embodiment may be
employed by providing pots 252 and heaters 253 as shown in FIG. 13
in the burnishing-preparation chamber 210.
[0167] The lubricant-layer preparation also may be carried out by a
spraying method. Concretely, a sprayer is provided at each side of
the substrate location in the burnishing-preparation chamber 210.
Lubricant diluted with solvent is sprayed from the sprayers onto
the substrate 9.
[0168] Next is described a magnetic disk manufacturing apparatus of
the fifth embodiment of the invention. FIG. 18 shows a main part of
the magnetic recording disk manufacturing apparatus of the fifth
embodiment of the invention.
[0169] The fifth embodiment is different from the described first
embodiment in the components on the burnishing chamber 24. In the
fifth embodiment, a cleaning means 88 is provided. The cleaning
means 88 cleans a surface of the burnishing tape 242 in vacuum
prior to the burnishing.
[0170] A film containing oxygen ions or sulfuric ions, dusts, or
organic substance such as fat and oil may adhere to the surface of
the burnishing tape 242 as contaminants. If the burnishing is
carried out in a state that such contaminants adhere to the surface
of the burnishing tape 242, the contaminants may transfer to the
substrate 9.
[0171] Considering this, the surface of the burnishing tape 242 is
cleaned by the cleaning means 88 prior to the burnishing in this
embodiment. Concretely, the cleaning means 88 is mainly composed of
an ion-beam source 881 provided in the burnishing chamber 24, and a
gas supply system 882 that supplies a material gas with the
ion-beam source 881.
[0172] The gas supply system 882 supplies an argon gas or an oxygen
gas. The ion-beam source 881 irradiates beam of argon ion or oxygen
ion onto the burnishing tape 242. Acceleration energy of the ion
beam is preferably 250-600 eV. An incident angle of the ion beam
onto to the burnishing tape 242 is preferably 30-40 degrees. If the
burnishing tape 242 may be damaged by the ion beam, the
acceleration energy is made lower, or the incident angle is made
smaller.
[0173] An irradiation pattern of the ion beam is a rectangle whose
width is the same as the burnishing tape 242 or slightly larger,
and whose length is about 30 mm. The ion-beam source 881 has a
focusing electrode, which focuses the ion beam so that this
irradiation pattern can be obtained.
[0174] The incident ion beam onto the burnishing tape 242 bombards
or scrapes the contaminants existing on the surface of the
burnishing tape 242, thereby removing them. As a result, the
surface of the burnishing tape 242 is cleaned. The burnishing is
carried out by pressing the cleaned surface of the burnishing tape
242 onto the substrate 9. Therefore, the contaminants are prevented
from adhering to the substrate 9.
[0175] Though the surface of the burnishing tape 242 is cleaned by
the ion beam in this embodiment, it is possible to clean it by
plasma or laser. It is also possible to clean the surface of the
burnishing tape 242 using the method in the fourth embodiment.
[0176] Next is described about an in-line type substrate processing
apparatus of an embodiment of the invention. The magnetic-recording
disk manufacturing apparatus shown in FIG. 1 is concurrently an
in-line type substrate processing apparatus. The apparatus
comprises a plurality of vacuum chambers 10-17, 20-29 connected
along two circumventive transfer paths 1, 2, and the shifting robot
63 that transfers the substrate 9 in vacuum without exposing the
substrate 9 to the atmosphere along the third transfer path 3 that
interconnects the first path 1 and the second path 2.
[0177] The described structure is a kind of circumventive in-line
type apparatus. U.S. Pat. No. 5,846,328 discloses the same kind of
apparatus. This type of apparatus has a merit that the substrate
holder does not bring contaminants in the atmosphere into the
apparatus because the substrate holder is not taken out to the
atmosphere. However, if it is intended to provide more vacuum
chambers in such a kind of in-line type apparatus, a transfer path
with a longer length is required. As imagined from FIG. 1, if the
transfer path is longer, a space surrounded by the transfer path is
larger. This space is not essential for the substrate processing.
If whole occupation space of the apparatus increases with an
increase in such a non-essential space, it is not a preferable
result.
[0178] Contrarily, by providing additional vacuum chambers along
another circumventive transfer path as in the apparatus of this
embodiment, the number of vacuum chambers can be increased without
much increase in the whole occupation space of the apparatus.
Therefore, this solution is very much suitable for the case that a
larger number of processes are intended to carry out without
breaking vacuum.
[0179] An application of the idea of such an in-line type substrate
processing apparatus is not limited to the described manufacture of
magnetic recording disks. For example, the idea can be applied to
manufacture of optical information recording media such as a
compact disc, and manufacture of display devices such as a liquid
crystal display, as far as the in-line type apparatus is used.
[0180] The circumventive transfer path may have another shape than
a rectangle. For example, the circumventive transfer path may have
a shape of a triangle, a circle, a pentagon, or the like. This
invention is not limited to the use of the substrate holder that
holds two substrates simultaneously. It is possible to employ a
substrate holder that holds only one substrate, or holds three or
more substrates simultaneously.
[0181] The magnetic-recording disk manufacturing apparatus of the
invention is not limited to the described in-line type. For
example, the invention includes a cluster-tool type apparatus where
process chambers, a load lock chamber and an unload lock chamber
are provided around a transfer chamber in which a transfer robot is
provided.
[0182] The term "magnetic-recording disk manufacturing apparatus"
generally means an apparatus for manufacturing a magnetic recording
disk. Therefore, it includes an apparatus with which all processes
for manufacturing a magnetic recording disk are carried out, and an
apparatus with which not all processes are carried out.
[0183] The term "magnetic recording disk" means a disk where
information is recorded utilizing an effect of magnetism in
general. Therefore, it includes a disk utilizing another effect
than magnetism in addition to the magnetism, such as a
magneto-optical recording disk.
* * * * *