U.S. patent application number 14/452247 was filed with the patent office on 2014-11-20 for ultraviolet-curable resin material for pattern transfer and magnetic recording medium manufacturing method using the same.
The applicant listed for this patent is KABUSHIKI KAISHA TOSHIBA. Invention is credited to Kazuyo Morita, Seiji Morita, Masatoshi Sakurai, Shinobu Sugimura.
Application Number | 20140342576 14/452247 |
Document ID | / |
Family ID | 43623302 |
Filed Date | 2014-11-20 |
United States Patent
Application |
20140342576 |
Kind Code |
A1 |
Morita; Kazuyo ; et
al. |
November 20, 2014 |
ULTRAVIOLET-CURABLE RESIN MATERIAL FOR PATTERN TRANSFER AND
MAGNETIC RECORDING MEDIUM MANUFACTURING METHOD USING THE SAME
Abstract
According to one embodiment, an ultraviolet curing curable resin
material for pattern transfer is provided. The resin contains
isobornyl acrylate, an acrylate having a fluorene skeleton, a
polyfunctional acrylate, and a polymerization initiator.
Inventors: |
Morita; Kazuyo;
(Yokohama-shi, JP) ; Morita; Seiji; (Yokohama-shi,
JP) ; Sugimura; Shinobu; (Yokohama-shi, JP) ;
Sakurai; Masatoshi; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA TOSHIBA |
Tokyo |
|
JP |
|
|
Family ID: |
43623302 |
Appl. No.: |
14/452247 |
Filed: |
August 5, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12872440 |
Aug 31, 2010 |
8829070 |
|
|
14452247 |
|
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Current U.S.
Class: |
438/780 |
Current CPC
Class: |
G03F 7/0002 20130101;
B82Y 10/00 20130101; C08F 220/18 20130101; B82Y 40/00 20130101;
H01L 21/02288 20130101; G11B 5/855 20130101; G03F 7/027 20130101;
H01L 21/02348 20130101; H01L 21/0212 20130101 |
Class at
Publication: |
438/780 |
International
Class: |
H01L 21/02 20060101
H01L021/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2009 |
JP |
2009-200860 |
Claims
1. A method for manufacturing a semiconductor device comprising:
bringing a semiconductor substrate and a transparent stamper into
contact with each other by a coating layer comprising an uncured
ultraviolet-curable resin material for pattern transfer containing
isobornyl acrylate, an acrylate having a fluorene skeleton
represented by formula (1), a polyfunctional acrylate, and a
polymerization initiator, the coating layer being interposed
between the semiconductor substrate and the transparent stamper,
##STR00006## wherein each of R.sub.1 and R.sub.2 is selected from
the group consisting of H, --C.sub.2H.sub.4--OCOCH.dbd.CH.sub.2,
--C.sub.3H.sub.6--OCOCH.dbd.CH.sub.2,
--CH.sub.4H.sub.8--OCOCH.dbd.CH.sub.2, ##STR00007## and each of
R.sub.3 and R.sub.4 is selected from the group consisting of H,
--CH.sub.3, --C.sub.2H.sub.5, --C.sub.3H.sub.7, --C.sub.4H.sub.9,
--Cl, --F, --Br, --NH.sub.2, --OH, and --OCOCH.dbd.CH.sub.2;
irradiating the coating layer with ultraviolet light, thereby
curing the ultraviolet-curable resin material for pattern transfer;
and removing the transparent stamper to form, on one surface of the
semiconductor substrate, a cured ultraviolet-curable resin material
layer for pattern transfer onto which a three-dimensional pattern
is transferred.
2. The method of claim 1, wherein the ultraviolet-curable resin
material contains 10 to 62% by weight of isobornyl acrylate, 10 to
50% by weight of the acrylate having a fluorene skeleton, 10 to 44%
by weight of the polyfunctional acrylate, and 0.1 to 6% by weight
of the polymerization initiator.
3. A method for manufacturing a semiconductor device comprising:
bringing a semiconductor substrate and a transparent stamper into
contact with each other by a coating layer comprising an uncured
ultraviolet-curable resin material for pattern transfer containing
isobornyl acrylate, an acrylate having a fluorene skeleton
represented by formula (1), a polyfunctional acrylate, an acrylate
having an adamantane skeleton, and a polymerization initiator, the
coating layer being interposed between the semiconductor substrate
and the transparent stamper, ##STR00008## wherein each of R.sub.1
and R.sub.2 is selected from the group consisting of H,
--C.sub.2H.sub.4--OCOCH.dbd.CH.sub.2,
--C.sub.3H.sub.6--OCOCH.dbd.CH.sub.2,
--CH.sub.4H.sub.8--OCOCH.dbd.CH.sub.2, ##STR00009## and each of
R.sub.3 and R.sub.4 is selected from the group consisting of H,
--CH.sub.3, --C.sub.2H.sub.5, --C.sub.3H.sub.7, --C.sub.4H.sub.9,
--Cl, --F, --Br, --NH.sub.2, --OH, and --OCOCH.dbd.CH.sub.2;
irradiating the coating layer with ultraviolet light, thereby
curing the ultraviolet-curable resin material for pattern transfer;
and removing the transparent stamper to form, on one surface of the
semiconductor substrate, a cured ultraviolet-curable resin material
layer for pattern transfer onto which a three-dimensional pattern
is transferred.
4. The method of claim 3, wherein the acrylate having an adamantane
skeleton is present in a weight percent between about 0 and 40.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of U.S. patent application
Ser. No. 12/872,440, filed Aug. 31, 2010, which is based upon and
claims the benefit of priority from Japanese Patent Application No.
2009-200860, filed Aug. 31, 2009, the entire contents of each of
which are incorporated herein by reference.
FIELD
[0002] Embodiments described herein relate generally to a method of
manufacturing a magnetic recording medium having discrete tracks on
the surface of a magnetic recording layer and, more particularly,
to an ultraviolet-curable resin material to be used as a resist
when transferring a discrete track shape.
BACKGROUND
[0003] Recently, the nano-imprinting techniques are attracting
attention in various fields in order to further increase the
density and accuracy.
[0004] For example, applications to semiconductors, optical
elements, magnetic recording media, and the like are being
examined.
[0005] A discrete track medium is attracting attention among other
magnetic recording media. In this discrete track medium, magnetic
interference between adjacent recording tracks is reduced by
separating the adjacent tracks by grooves or guard bands consisting
of a nonmagnetic material, in order to further increase the
density.
[0006] When manufacturing this discrete track medium, discrete
track patterns of a magnetic layer can be formed by applying the
nano-imprinting technique by using a stamper. When magnetic layer
patterns corresponding to servo area signals are formed together
with recording track patterns by imprinting, it is possible to
obviate the servo track writing step required in the manufacture of
the conventional magnetic recording media. This leads to a cost
reduction as well.
[0007] As the process of forming discrete track patterns as
described above, it is possible to use, e.g., a manufacturing
process of transferring resist patterns from an Ni stamper by
high-pressure imprinting or thermal imprinting as disclosed in,
e.g., Jpn. Pat. Appln. KOKAI Publication No. 2007-186570.
Unfortunately, this process is unsuitable for mass-production
because the life of the Ni stamper is short. Also, when the data
density is increased to make tracks finer, resist patterns cannot
be well transferred.
[0008] From the foregoing, the use of optical nano-imprinting is
attracting attention as another nano-imprinting technique.
[0009] To transfer patterns onto a resist on a discrete track
medium by using optical nano-imprinting, a resin stamper is first
duplicated from an Ni stamper (mother stamper) by injection
molding, and bonded in a vacuum to an uncured ultraviolet-curable
resin layer to be used as a resist. This method is found to be able
to reduce the cost and suitable for micropatterning.
[0010] The characteristics required of the ultraviolet-curable
resin for transfer onto the above-mentioned discrete track medium
are the resistance against etching for processing transferred
patterns, in addition to the property of coating onto the medium,
the viscosity, the curing property, the property of separation from
the resin stamper, and the cure shrinkage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] A general architecture that implements the various feature
of the embodiments will now be described with reference to the
drawings. The drawings and the associated descriptions are provided
to illustrate the embodiments and not to limit the scope of the
invention.
[0012] FIGS. 1A, 1B, 1C and 1D are views showing a pattern transfer
method to be used in the embodiment;
[0013] FIG. 2 is a view showing a magnetic recording/reproduction
apparatus for performing recording and reproduction with respect to
a magnetic recording medium; and
[0014] FIG. 3 is a view showing an embodiment of a discrete
magnetic recording medium manufacturing method.
DETAILED DESCRIPTION
[0015] Various embodiments will be described hereinafter with
reference to the accompanying drawings.
[0016] In general, according to one embodiment, an
ultraviolet-curable resin material for pattern transfer is
provided, which contains an acrylate having a fluorene skeleton
represented by formula (1) below, isobornyl acrylate represented by
formula (2) below, a polyfunctional acrylate, and a polymerization
initiator.
##STR00001##
[0017] wherein each of R.sub.1 and R.sub.2 is one of --H,
--OCOCH.dbd.CH.sub.2,
[0018] --CH.sub.2--OCOCH.dbd.CH.sub.2,
--C.sub.2H.sub.4--OCOCH.dbd.CH.sub.2,
--C.sub.3H.sub.6--OCOCH.dbd.CH.sub.2, and
[0019] --CH.sub.4H.sub.8--OCOCH.dbd.CH.sub.2.
[0020] It is possible to substitute, e.g.,
##STR00002##
[0021] Also, R.sub.3 and R.sub.4 can be substituted with, e.g., H,
--CH.sub.3, --C.sub.2H.sub.5, --C.sub.3H.sub.7, --C.sub.4H.sub.9,
--Cl, --F, --Br, --NH.sub.2, --OH, or --OCOCH.dbd.CH.sub.2.
[0022] In particular, 9,9'-bisphenylfluorene acrylate,
9,9'-bisphenylfluorene EO-modified acrylate, or
9,9'-bis(3-methylphenyl)fluorene acrylate has a higher etching
resistance.
[0023] The embodiment uses the ultraviolet-curable resin material
for pattern transfer containing the acrylate having a fluorene
skeleton, isobornyl acrylate, the polyfunctional acrylate, and the
polymerization initiator, and hence can increase the etching
resistance without deteriorating the ultraviolet curing property
and the property of separation after curing. When using this
ultraviolet-curable resin material for pattern transfer, therefore,
patterns can accurately be transferred from a stamper.
[0024] Use of an acrylate having a fluorene skeleton can improve
the etching resistance.
[0025] Also, isobornyl acrylate has a relatively low viscosity of 9
CP and a relatively high glass transition point Tg. In addition,
isobornyl acrylate has a high etching resistance because it has an
alicyclic structure. When using a material containing two
components, i.e., isobornyl acrylate and the polymerization
initiator as the ultraviolet-curable resin material for pattern
transfer, the hardness of the cured film was insufficient. The
hardness of the cured film was insufficient even when a
monofunctional monomer, a bifunctional monomer, and isobornyl
acrylate were combined. When a trifunctional monomer was combined,
the hardness of the cured film was sufficient while the etching
resistance remained high. A polyfunctional monomer having an order
higher than that of a trifunctional monomer often increases the
viscosity.
[0026] Furthermore, isobornyl acrylate has a high etching
resistance because it has an alicyclic structure and a high glass
transition temperature Tg. However, the property of separation from
a resin stamper often deteriorates because, e.g., the hardness of
the cured film readily increases, and the surface tension is not
high.
[0027] A magnetic recording medium manufacturing method according
to one embodiment is a method including bonding, in a vacuum, the
surface of a magnetic recording layer of a magnetic recording
medium including a data area and a servo area, and a
three-dimensional pattern surface of a resin stamper, with a
coating layer of an uncured ultraviolet-curable resin material for
pattern transfer being interposed between the surface of the
magnetic recording layer and the three-dimensional pattern
surface,
[0028] curing the coating layer of the uncured ultraviolet-curable
resin material by irradiating the coating layer with ultraviolet
light,
[0029] separating the resin stamper to form, on one surface of the
magnetic recording medium, a cured ultraviolet-curable resin
material layer onto which a three-dimensional pattern is
transferred, and
[0030] performing dry etching by using the cured
ultraviolet-curable resin material layer as a mask, thereby forming
a three-dimensional pattern on the surface of the magnetic
recording layer,
[0031] wherein the ultraviolet-curable resin material for pattern
transfer contains an acrylate having a fluorene skeleton, isobornyl
acrylate, a polyfunctional acrylate, and a polymerization
initiator.
[0032] In addition to the acrylates and polymerization initiator
described above, an additive such as an adhesive can be mixed in an
amount of 3 wt % or less in the ultraviolet-curable resin material
for pattern transfer of the embodiment as needed.
[0033] The ultraviolet-curable resin material for pattern transfer
of the present invention can have a viscosity of 9 to 15 cp at
25.degree. C.
[0034] When using an ultraviolet-curable resin material consisting
of a monomer, oligomer, and polymerization initiator and containing
no solvent, the groove width increases after dry etching because
the etching rate of Ar milling in the dry etching is high. This
makes it difficult to form fine grooves.
[0035] Also, an oligomer having a large molecular weight is
presumably the cause of the decrease in dry etching resistance.
[0036] As the ultraviolet-curable resin material according to the
embodiment, therefore, the use of an ultraviolet-curable resin
material consisting of a plurality of predetermined types of
monomers and a polymerization initiator and containing neither an
oligomer nor a solvent has been examined.
[0037] Furthermore, the ultraviolet-curable resin material
according to the embodiment is a radical polymerization-based
material, and an acrylate is used in the embodiment because a
photopolymerization reaction slows down when the monomer is a
methacrylate.
[0038] The content of isobornyl acrylate is 10 to 62 wt %, that of
the acrylate having a fluorene skeleton is 10 to 50 wt %, that of
the polyfunctional acrylate is 10 to 44 wt %, and that of the
polymerization initiator is 0.1 to 6 wt %.
[0039] The ultraviolet-curable resin having these contents further
improves in viscosity, separation property, curing property,
coating film thickness, and etching rate.
[0040] The polyfunctional acrylate usable in the embodiment
includes a bifunctional acrylate, a trifunctional acrylate, and
tetrafunctional and higher-order-functional acrylates.
[0041] Examples of the bifunctional acrylate are
[0042] 1,3-butylene glycol diacrylate,
[0043] 1,4-butanediol diacrylate,
[0044] diethylene glycol diacrylate,
[0045] 1,6-hexanediol diacrylate,
[0046] neopentyl glycol diacrylate,
[0047] polyethylene glycol (200) diacrylate,
[0048] tetraethylene glycol diacrylate,
[0049] triethylene glycol diacrylate,
[0050] tripropylene glycol diacrylate,
[0051] polyethylene glycol (400) diacrylate,
[0052] ethoxylated (3) bisphenol A diacrylate,
[0053] cyclohexane dimethanol diacrylate,
[0054] dipropylene glycol diacrylate,
[0055] acrylate ester (dioxane glycol diacrylate),
[0056] alkoxylated hexanediol diacrylate,
[0057] alkoxylated cyclohexane dimethanol diacrylate,
[0058] ethoxylated (4) bisphenol A diacrylate,
[0059] ethoxylated (10) bisphenol A diacrylate,
[0060] polyethylene glycol (600) diacrylate,
[0061] tricyclodecane dimethanol diacrylate,
[0062] propoxylated (2) neopentyl glycol diacrylate,
[0063] ethoxylated (30) bisphenol A diacrylate, and
[0064] alkoxylated neopentyl glycol diacrylate.
[0065] As the trifunctional acrylate, it is possible to use,
e.g.,
[0066] trimethylolpropane triacrylate,
[0067] trimethylolpropane PO-modified triacrylate [0068] (the
number of POs (propoxy groups): 2, 3, 4, 6),
[0069] trimethylolpropane EO-modified triacrylate [0070] (the
number of EOs (ethoxy groups): 3, 6, 9, 15, 20),
[0071] tris(2-hydroxyethyl)isocyanurate triacrylate,
[0072] pentaerythritol triacrylate,
[0073] pentaerythritol EO-modified triacrylate,
[0074] EO-modified glycerin triacrylate,
[0075] propoxylated (3) glyceryl triacrylate,
[0076] highly propoxylated (5.5) glyceryl triacrylate,
[0077] trisacryloyloxyethyl phosphate, and
[0078] .epsilon.-caprolactone-modified
tris(acryloxyethyl)isocyanurate.
[0079] As the tetrafunctional and higher-order-functional
acrylates, it is possible to use, e.g.,
[0080] trisacryloyloxyethyl phosphate,
[0081] pentaerythritol tetraacrylate,
[0082] ditrimethylolpropane tetraacrylate,
[0083] ethoxylated (4) pentaerythritol tetraacrylate, and
[0084] dipentaerythritol pentaacrylate.
[0085] It is also possible to use a polyfunctional oligomer.
[0086] Examples of the oligomer are a urethane acrylate oligomer,
epoxy acrylate oligomer, and polyester acrylate oligomer. Although
any of these oligomers is usable, an acrylate oligomer containing
an aromatic group is particularly favorable in respect of the
etching resistance. An aromatic urethane acrylate oligomer is most
particularly favorable in respect of the separation property,
etching resistance, and compatibility. The oligomer may also
contain Si or F, and an oligomer containing Si is particularly
suitable because it functions as a release agent as well.
[0087] An acrylate having an adamantane skeleton can further be
added to the ultraviolet-curable resin material according to the
embodiment.
[0088] Examples of the acrylate having an adamantane skeleton
usable in the embodiment are
[0089] 2-methyl-2-adamantyl acrylate,
[0090] 2-ethyl-2-adamantyl acrylate,
[0091] 3-hydroxy-1-adamantyl acrylate,
[0092] 1-adamantyl acrylate,
[0093] 2-methyl-2-adamantyl methacrylate,
[0094] 2-ethyl-2-adamantyl methacrylate,
[0095] 3-hydroxy-1-adamantyl methacrylate,
[0096] 1-admantyl methacrylate,
[0097] 1,3-adamantane diol diacrylate, and
[0098] 1,3-adamantane dimethanol diacrylate.
[0099] In particular,
[0100] 2-methyl-2-adamantyl acrylate,
[0101] 2-ethyl-2-adamantyl acrylate, and
[0102] 1-adamantyl acrylate
[0103] are favorable.
[0104] The content of the acrylate having an adamantane skeleton in
the ultraviolet-curable resin material for pattern transfer of the
embodiment is 0 to 40 wt %.
[0105] Examples of the polymerization initiator usable in the
embodiment are an alkylphenone-based photopolymerization initiator,
acylphosphine oxide-based polymerization initiator,
titanocene-based polymerization initiator, oxime ester-based
photopolymerization initiator, and oxime ester acetate-based
photopolymerization initiator.
[0106] Practical examples of the above-mentioned polymerization
initiators are
[0107] 2,2-dimethoxy-1,2-diphenylethane-1-on (IRGACURE651
manufactured by Ciba Specialty Chemicals),
[0108] 1-hydroxy-cyclohexyl-phenyl-ketone (IRGACURE184 manufactured
by Ciba Specialty Chemicals), and
[0109] 2-hydroxy-2-methyl-1-phenyl-propane-1-on (DAROCUR1173
manufactured by Ciba Specialty Chemicals).
[0110] Other examples are IRGACURE2959, IRGACURE127, IRGACURE907,
IRGACURE369, IRGACURE379, DAROCUR TPO, IRGACURE819, IRGACURE784,
IRGACURE OXE01, IRGACURE OXE02, and IRGACURE754 (all are
manufactured by Ciba Specialty Chemicals).
[0111] It is possible to select an optimum polymerization initiator
in accordance with the wavelength of a lamp for use in UV
irradiation.
[0112] As the lamp for use in UV irradiation, it is possible to
use, e.g., a high-pressure mercury lamp, metal halide lamp, or
xenon flash lamp.
[0113] An outline of a pattern transfer method to be used in the
embodiment will be explained below with reference to FIGS. 1A to
1D.
[0114] FIGS. 1A to 1D illustrate the transfer of patterns onto one
surface of a medium substrate. As shown in FIG. 1A, a medium
substrate 51 is set on a spinner 41. As shown in FIG. 1B, while the
medium substrate 51 is spun together with the spinner 41, the
ultraviolet-curable resin (2P resin) according to the embodiment is
dropped from a dispenser 42 and spin-coated. As shown in FIG. 1C,
in a vacuum chamber 81, one surface of the magnetic recording
medium 51 and the pattern surface of a transparent stamper 71 are
bonded in a vacuum with the 2P resin layer (not shown) being
interposed between them. As shown in FIG. 1D, the 2P resin layer is
cured by emitting UV light from a UV light source 43 through the
transparent stamper 71 at atmospheric pressure. After the step
shown in FIG. 1D, the transparent stamper 71 is separated.
[0115] Examples of a magnetic disk substrate usable in the
embodiment are a glass substrate, an Al-based alloy substrate, a
ceramic substrate, a carbon substrate, an Si single-crystal
substrate having an oxidized surface, and a substrate obtained by
forming an NiP layer on the surface of any of these substrates. As
the glass substrate, amorphous glass or crystallized glass can be
used. Examples of the amorphous glass are soda lime glass and
alumino silicate glass. An example of the crystallized glass is
lithium-based crystallized glass. As the ceramic substrate, it is
possible to use a sintered product mainly containing aluminum
oxide, aluminum nitride, or silicon nitride, or a material formed
by fiber-reinforcing the sintered product. Plating or sputtering is
used to form the NiP layer on the substrate surface.
[0116] When manufacturing a perpendicular magnetic recording
medium, a so-called perpendicular double-layered medium can be
formed by forming a perpendicular magnetic recording layer on a
soft magnetic underlayer (SUL) on a substrate. The soft magnetic
underlayer of the perpendicular double-layered medium passes a
recording magnetic field from a recording magnetic pole, and
returns the recording magnetic field to a return yoke placed near
the recording magnetic pole. That is, the soft magnetic underlayer
performs a part of the function of a recording head; the soft
magnetic underlayer applies a steep perpendicular magnetic field to
the recording layer, thereby increasing the recording
efficiency.
[0117] An example of the soft magnetic underlayer usable in the
embodiment is a high-k material containing at least one of Fe, Ni,
and Co. Examples of the material are FeCo-based alloys such as FeCo
and FeCoV, FeNi-based alloys such as FeNi, FeNiMo, FeNiCr, and
FeNiSi, FeAl-based and FeSi-based alloys such as FeAl, FeAlSi,
FeAlSiCr, FeAlSiTiRu, and FeAlO, FeTa-based alloys such as FeTa,
FeTaC, and FeTaN, and FeZr-based alloys such as FeZrN.
[0118] As the soft magnetic underlayer, it is also possible to use
a material having a microcrystal structure such as FeAlO, FeMgO,
FeTaN, or FeZrN containing 60 at % or more of Fe, or a material
having a granular structure in which fine crystal grains are
dispersed in a matrix.
[0119] As another material of the soft magnetic underlayer, it is
possible to use a Co alloy containing Co and at least one of Zr,
Hf, Nb, Ta, Ti, and Y. The content of Co can be 80 at % or more. An
amorphous layer is readily formed when a film of the Co alloy is
formed by sputtering. The amorphous soft magnetic material has none
of magnetocrystalline anisotropy, a crystal defect, and a grain
boundary, and hence has superb soft magnetism. It is also possible
to reduce the noise of the medium by using the amorphous soft
magnetic material. Favorable examples of the amorphous soft
magnetic material are CoZr-based, CoZrNb-based, and CoZrTa-based
alloys.
[0120] Another underlayer may also be formed below the soft
magnetic underlayer in order to improve the crystallinity of the
soft magnetic underlayer or improve the adhesion to the substrate.
As the underlayer material, it is possible to use Ti, Ta, W, Cr,
Pt, an alloy containing any of these materials, or an oxide or
nitride of any of these materials.
[0121] An interlayer consisting of a nonmagnetic material can be
formed between the soft magnetic underlayer and the perpendicular
magnetic recording layer. The interlayer interrupts the exchange
coupling interaction between the soft magnetic underlayer and the
recording layer, and controls the crystallinity of the recording
layer. As the interlayer material, it is possible to use Ru, Pt,
Pd, W, Ti, Ta, Cr, Si, an alloy containing any of these materials,
or an oxide or nitride of any of these materials.
[0122] To prevent spike noise, it is possible to divide the soft
magnetic underlayer into a plurality of layers, and
antiferromagnetically couple these layers with 0.5- to 1.5-nm-thick
Ru films being sandwiched between them. Also, the soft magnetic
layer can be coupled by exchange coupling with a hard magnetic film
having in-plane anisotropy such as CoCrPt, SmCo, or FePt, or a
pinning layer consisting of an antiferromagnetic material such as
IrMn or PtMn. To control the exchange coupling force, a magnetic
layer such as a Co layer or a nonmagnetic layer such as a Pt layer
can be stacked above and below the Ru layer.
[0123] As the perpendicular magnetic recording layer usable in the
embodiment, it is possible to use, e.g., a material mainly
containing Co, containing at least Pt, containing Cr as needed, and
further containing an oxide (e.g., silicon oxide or titanium
oxide). In this perpendicular magnetic recording layer, the
magnetic crystal grains can form a pillar structure. In the
perpendicular magnetic recording layer having this structure, the
orientation and crystallinity of the magnetic crystal grains are
favorable. As a consequence, a signal-to-noise ratio (SNR) suitable
for high-density recording can be obtained. The amount of oxide is
important to obtain the above structure. The content of the oxide
can be 3 to 12 mol %, and can also be 5 to 10 mol %, with respect
to the total amount of Co, Pt, and Cr. When the content of the
oxide in the perpendicular magnetic recording layer falls within
the above range, the oxide deposits around the magnetic grains, so
the magnetic grains can be isolated and reduced in size. If the
content of the oxide exceeds the above range, the oxide remains in
the magnetic grains and deteriorates the orientation and
crystallinity of the magnetic grains. Furthermore, the oxide
deposits above and below the magnetic grains. Consequently, the
pillar structure in which the magnetic grains extend vertically
through the perpendicular magnetic recording layer is often not
formed. On the other hand, if the content of the oxide is less than
the above range, the magnetic grains are insufficiently isolated
and reduced in size. As a result, noise increases during recording
and reproduction, and this often makes it impossible to obtain a
signal-to-noise ratio (SNR) suited to high-density recording.
[0124] The content of Pt in the perpendicular magnetic recording
layer can be 10 to 25 at %. When the Pt content falls within the
above range, a uniaxial magnetic anisotropy constant Ku necessary
for the perpendicular magnetic recording layer is obtained. In
addition, the crystallinity and orientation of the magnetic grains
improve. Consequently, a thermal decay characteristic and
recording/reproduction characteristic suited to high-density
recording are obtained. If the Pt content exceeds the above range,
a layer having the fcc structure is formed in the magnetic grains,
and the crystallinity and orientation may deteriorate. On the other
hand, if the Pt content is less than the above range, it is often
impossible to obtain Ku, i.e., a thermal decay characteristic
suitable for high-density recording.
[0125] The content of Cr in the perpendicular magnetic recording
layer can be 0 to 16 at %, and can also be 10 to 14 at %. When the
Cr content falls within the above range, it is possible to maintain
high magnetization without decreasing the uniaxial magnetic
anisotropy constant Ku of the magnetic grains. Consequently, a
recording/reproduction characteristic suited to high-density
recording and a sufficient thermal decay characteristic are
obtained. If the Cr content exceeds the above range, the thermal
decay characteristic worsens because Ku of the magnetic grains
decreases. In addition, the crystallinity and orientation of the
magnetic grains worsen. As a consequence, the
recording/reproduction characteristic tends to worsen.
[0126] The perpendicular magnetic recording layer can contain one
or more additive elements selected from B, Ta, Mo, Cu, Nd, W, Nb,
Sm, Tb, Ru, and Re, in addition to Co, Pt, Cr, and the oxide. These
additive elements can promote the reduction in size of the magnetic
grains, or improve the crystallinity and orientation of the
magnetic grains. This makes it possible to obtain a
recording/reproduction characteristic and thermal decay
characteristic more suitable for high-density recording. The total
content of these additive elements can be 8 at % or less. If the
total content exceeds 8 at %, a phase other than the hcp phase is
formed in the magnetic grains, and this disturbs the crystallinity
and orientation of the magnetic grains. As a result, it is often
impossible to obtain a recording/reproduction characteristic and
thermal decay characteristic suited to high-density recording.
[0127] Other examples of the material of the perpendicular magnetic
recording layer are a CoPt-based alloy, a CoCr-based alloy, a
CoPtCr-based alloy, CoPtO, CoPtCrO, CoPtSi, and CoPtCrSi. As the
perpendicular magnetic recording layer, it is also possible to use
a multilayered film containing Co and an alloy mainly containing at
least one element selected from the group consisting of Pt, Pd, Rh,
and Ru. It is further possible to use a multilayered film such as
CoCr/PtCr, CoB/PdB, or CoO/RhO obtained by adding Cr, B, or O to
each layer of the above-mentioned multilayered film.
[0128] The thickness of the perpendicular magnetic recording layer
can be 5 to 60 nm, and can also be 10 to 40 nm. A perpendicular
magnetic recording layer having a thickness falling within this
range is suited to a high recording density. If the thickness of
the perpendicular magnetic recording layer is less than 5 nm, the
reproduction output becomes too low, so the noise component often
becomes higher than the reproduction output. On the other hand, if
the thickness of the perpendicular magnetic recording layer exceeds
40 nm, the reproduction output becomes too high and tends to
distort the waveform. The coercive force of the perpendicular
magnetic recording layer can be 237,000 A/m (3,000 Oe) or more. If
the coercive force is less than 237,000 A/m (3,000 Oe), the thermal
decay resistance tends to decrease. The perpendicular squareness
ratio of the perpendicular magnetic recording layer can be 0.8 or
more. If the perpendicular squareness ratio is less than 0.8, the
thermal decay resistance often decreases.
[0129] A protective layer can be formed on the perpendicular
magnetic recording layer.
[0130] The protective layer prevents the corrosion of the
perpendicular magnetic recording layer, and also prevents damages
to the medium surface when a magnetic head comes in contact with
the medium. Examples of the material of the protective layer are
materials containing C, SiO.sub.2, and ZrO.sub.2. The thickness of
the protective layer can be 1 to 10 nm. When the thickness of the
protective layer falls within the above range, the distance between
the head and the medium can be decreased. This is suitable for
high-density recording.
[0131] The surface of the perpendicular magnetic recording medium
can be coated with a lubricant, e.g., perfluoropolyether, alcohol
fluoride, or fluorinated carboxylic acid.
[0132] FIG. 2 is a view showing a magnetic recording/reproduction
apparatus for performing recording and reproduction with respect to
the magnetic recording medium.
[0133] This magnetic recording apparatus includes, in a housing 61,
a magnetic recording medium 62, a spindle motor 63 for rotating the
magnetic recording medium 62, a head slider 64 including a
recording/reproduction head, a head suspension assembly (a
suspension 65 and actuator arm 66) for supporting the head slider
64, a voice coil motor 67, and a circuit board.
[0134] The magnetic recording medium 62 is attached to and rotated
by the spindle motor 63, and various kinds of digital data are
recorded by the perpendicular magnetic recording method. The
magnetic head incorporated into the head slider 64 is a so-called
composite head, and includes a write head having a single-pole
structure and a read head using a GMR or TMR film. The suspension
65 is held at one end of the actuator arm 66, and supports the head
slider 64 so as to oppose it to the recording surface of the
magnetic recording medium 62. The actuator arm 66 is attached to a
pivot 68. The voice coil motor 67 is formed as an actuator at the
other end of the actuator arm 64. The voice coil motor 67 drives
the head suspension assembly to position the magnetic head in an
arbitrary radial position of the magnetic recording medium 62. The
circuit board includes a head IC, and generates, e.g., a voice coil
motor driving signal, and control signals for controlling read and
write by the magnetic head.
[0135] An address signal and the like can be reproduced from the
processed magnetic recording medium by using this magnetic disk
apparatus.
[0136] A magnetic disk in which the track density was 325 kTPI
[Track Per Inch, equivalent to a track pitch of 78 nm] in a data
zone having a radius of 9 to 22 mm was manufactured by using the
method of the embodiment.
[0137] To manufacture the magnetic disk having a servo area as
described above, imprinting is performed using a stamper having
three-dimensional patterns corresponding to magnetic layer patterns
on the magnetic disk. Note that the surface of the
three-dimensional patterns of the magnetic layer formed by
imprinting and subsequent processing may also be planarized by
burying a nonmagnetic material in recesses.
[0138] A method of manufacturing the magnetic disk of this
embodiment will be explained below.
[0139] First, a stamper was manufactured.
[0140] An Si wafer having a diameter of 6 inches was prepared as a
substrate of a master as a template of the stamper. On the other
hand, resist ZEP-520A available from ZEON was diluted to 1/2 with
anisole, and the solution was filtered through a 0.05-.mu.m filter.
The Si wafer was spin-coated with the resist solution and prebaked
at 200.degree. C. for 3 min, thereby forming a resist layer about
50 nm thick.
[0141] An electron beam lithography system having a ZrO/W
thermal-field-emission electron gun emitter was used to directly
write desired patterns on the resist on the Si wafer at an
acceleration voltage of 50 kV. This lithography was performed using
a signal source that synchronously generates signals for forming
servo patterns, burst patterns, address patterns, and track
patterns, signals to be supplied to a stage driving system (a
so-called X-.theta. stage driving system including a moving
mechanism having a moving axis in at least one direction and a
rotating mechanism) of the lithography system, and an electron beam
deflection control signal. During the lithography, the stage was
rotated at a CLV (Constant Linear Velocity) of 500 mm/s, and moved
in the radial direction as well. Also, concentric track areas were
written by deflecting the electron beam for every rotation. Note
that the feeding speed was 7.8 nm per rotation, and one track
(equivalent to one address bit width) was formed by ten
rotations.
[0142] The resist was developed by dipping the Si wafer in ZED-N50
(available from ZEON) for 90 seconds. After that, the Si wafer was
rinsed as it was dipped in ZMD-B (available from ZEON) for 90
seconds, and dried by air blow, thereby manufacturing a resist
master (not shown).
[0143] A conductive film of Ni was formed on the resist master by
sputtering. More specifically, pure nickel was used as a target,
and, after a chamber was evacuated to 8.times.10.sup.-3 Pa, the
pressure was adjusted to 1 Pa by supplying gaseous argon, and
sputtering was performed in the chamber for 40 seconds by applying
a DC power of 400 W, thereby depositing a conductive film about 10
nm thick.
[0144] The resist master having this conductive film was dipped in
a nickel sulfamate plating solution (NS-160 available from Showa
Chemical Industry), and Ni electroforming was performed for 90 min,
thereby forming an electroformed film about 300 .mu.m thick. The
electroforming bath conditions were as follows.
[0145] Electroforming Bath Conditions
[0146] Nickel sulfamate: 600 g/L
[0147] Boric acid: 40 g/L
[0148] Surfactant (sodium lauryl sulfate): 0.15 g/L
[0149] Solution temperature: 55.degree. C.
[0150] pH: 4.0
[0151] Current density: 20 A/dm.sup.2
[0152] The electroformed film and conductive film were separated
together with the resist residue from the resist master. The resist
residue was removed by oxygen plasma ashing. More specifically,
plasma ashing was performed for 20 min by applying a power of 100 W
in a chamber in which the pressure was adjusted to 4 Pa by
supplying gaseous oxygen at 100 mL/min.
[0153] A father stamper 1 including the conductive film and
electroformed film as described above was obtained. After that, as
shown in FIG. 3(a), electroforming was further performed to
duplicate a mother stamper 2. An injection molding stamper was
obtained by removing unnecessary portions of the mother stamper 2
by a metal blade.
[0154] As shown in FIG. 3(b), a resin stamper 3 was duplicated from
the mother stamper 2 by using an injection molding apparatus
manufactured by TOSHIBA MACHINE. As the molding material, cyclic
olefin polymer ZEONOR 1060R available from ZEON was used. However,
polycarbonate material AD5503 available from TEIJIN CHEMICALS may
also be used.
[0155] Then, a magnetic disk was manufactured.
[0156] A magnetic recording layer 5 was formed by sputtering on a
disk substrate made of doughnut-like glass 1.8 inches in diameter
as shown in FIG. 3(g) and FIG. 3(h). A 3-nm-thick metal mask layer
6 was stacked on this magnetic recording layer as shown in FIG.
3(i). Examples of a metal usable as the metal mask layer are Ag,
Al, Au, C, Cr, Cu, Ni, Pt, Pd, Ru, Si, Ta, Ti, Zn, and alloys
(e.g., CrTi, CoB, CoPt, CoZrNb, NiTa, NiW, Cr--N, SiC, and
TiO.sub.x) containing these metals. In particular, Si and Cu are
superior in property of separation from a resin stamper and
processability to other metals. The film thickness of the metal
mask layer is determined by the processability, and further as
small as possible. In this embodiment, a 3-nm-thick Cu layer was
stacked on the magnetic recording layer.
[0157] After a surface protection layer 6 was formed on a magnetic
recording layer 5 as shown in FIG. 3(i), a resist 7 consisting of
an ultraviolet-curable resin material was diluted to 3 wt % by
2,2,3,3-tetrafluoro-1-propanol, and the solution was spin-coated at
a rotational speed of 10,000 rpm as shown in FIG. 3(j) and FIG.
3(k).
[0158] As shown in FIG. 3(c), the resin stamper 3 was bonded to the
ultraviolet-curable resin resist 7 on the surface of the disk
substrate by vacuum bonding, and the resin was cured by ultraviolet
irradiation. After that, the resin stamper 3 was separated as shown
in FIG. 3(d).
[0159] In a three-dimensional pattern formation process performed
by ultraviolet imprinting, the resist residue remains on the
bottoms of pattern recesses.
[0160] Then, the resist residue on the bottoms of pattern recesses
was removed by RIE using gaseous oxygen. As shown in FIG. 3(e), the
magnetic recording layer was etched by Ar ion milling.
Subsequently, as shown in FIG. 3(f), the resist patterns were
removed by oxygen RIE. In addition, a carbon protective layer (not
shown) was deposited on the entire surface. After that, the
manufactured magnetic disk was coated with a lubricant.
[0161] In the magnetic disk medium described above, the magnetic
recording layer was etched to the bottom in a portion where no
resist mask was formed. However, it is also possible to stop Ar ion
milling halfway to obtain a medium having projections and recesses.
Alternatively, it is possible to obtain a medium by imprinting a
stamper onto a resist on a substrate without initially forming any
magnetic layer, making the substrate shape three-dimensional in
advance by etching or the like, and then forming a magnetic film.
Furthermore, in any medium including the above-mentioned media, the
grooves may also be filled with a certain nonmagnetic material.
[0162] Although the ultraviolet-curable resin was diluted to 3 wt %
by 2,2,3,3,-tetrafluoro-1-propanol, the ultraviolet-curable resin
can also be used without being diluted depending on the viscosity
and coating method of the resin. As the solvent for dilution, it is
also possible to use, e.g., anisole, isopropyl alcohol, ethanol,
acetone, cyclic hydrofluorocarbon (e.g., ZEORORA H available from
ZEON), or cyclic hydrofluoroether.
Example
[0163] The embodiment will be explained in more detail below by way
of its example.
[0164] A resin stamper was duplicated by the above-mentioned method
by using one Ni stamper, and resist mask transfer was performed
using an ultraviolet-curable resin.
[0165] The ultraviolet-curable resin was evaluated for five items,
i.e., the curing property, separation property, coating property,
transfer property, and Ar sputter etching rate.
[0166] The curing property was evaluated after transfer by wiping
up the resin with cloth wetted by ethanol. The evaluation was
.largecircle. when there was no change, .DELTA. when there were
fine scratches, and x when the wiped portion entirely peeled
off.
[0167] The separation property was evaluated as .largecircle. when
no 2P resin remained on the resin stamper after separation, .DELTA.
when the 2P resin slightly remained, and x when the 2P resin
remained in a wide area.
[0168] The coating property was evaluated by visually observing the
surface of the ultraviolet-curable resin after transfer. The
evaluation was .largecircle. when the color was uniform, .DELTA.
when the color was slightly nonuniform, and x when the color was
largely nonuniform as if phase separation occurred.
[0169] The transfer property was evaluated by observing the
transferred patterns on the ultraviolet-curable resin with an AFM.
The evaluation was .largecircle. when the groove depth remained
unchanged from that of the resin stamper, .DELTA. when the groove
depth varied, and x when the groove depth changed (decreased).
[0170] The Ar sputter etching rate was measured by performing
plasma etching in an Ar ambient at a pressure of 1 Pa and an RF
power of 100 W for 200 seconds by using 51A manufactured by
Shibaura Mechatronics. Before and after the etching, the film
thickness of the ultraviolet-curable resin was measured by using
Dektak 6M Stylus Surface Profiler manufactured by Ulvac. The
etching rate was calculated by normalizing the difference between
the film thicknesses before and after the etching by the etching
time. As the etching resistance increases, the processability when
using the ultraviolet-curable resin improves, so the etching rate
can be decreased. For example, an etching rate of 0.15 nm/s or less
can be used as a reference.
[0171] Although a transfer pattern sample by which the ratio of the
land to the groove was 1:1 was used in the above example, the
embodiment is not limited to this. The characteristics of the
apparatus for checking the RRO characteristic make tracking
impossible to perform if PP/SUM as a value obtained by normalizing
an amplitude (p-p) of a push-pull signal PP by a voltage value
(p-G) of a sum signal SUM satisfies at least PP/SUM<0.1.
Accordingly, it is possible to select a land-to-groove ratio at
which tracking can be performed by preventing this.
Example
[0172] Magnetic recording media were manufactured by transferring
patterns onto magnetic recording layers by the above-mentioned
method by using ultraviolet-curable resin samples A to V.
[0173] Tables 1 and 2 show the contents of ultraviolet-curable
resin samples A to Z, and Tables 3 and 4 show the results.
[0174] Symbols used in Tables 1 and 2 will be explained below.
##STR00003## ##STR00004## ##STR00005##
[0175] IRGACURE369: Polymerization initiator manufactured by Ciba
Specialty Chemicals
[0176] DAROCUR1173: Polymerization initiator manufactured by Ciba
Specialty Chemicals
[0177] PU370: Trifunctional aromatic urethane acrylate oligomer
manufactured by MIWON
[0178] SIU2400: 10-functional Si acrylate oligomer manufactured by
MIWON
[0179] Ultraviolet-curable resin samples B, C, D, F, H, I, J, K, L,
M, N, R, U, V, W, and X were found to be ultraviolet-curable resins
suitably usable for the purpose of transferring patterns onto a
magnetic recording medium in respect of all of the curing property,
separation property, coating property, transfer property, and
etching rate.
[0180] By contrast, samples A, O, Q, S, and Y were inferior in
etching resistance because the etching rate was high. The content
of IBOA of sample A was smaller than that of sample B. This example
shows that the content of IBOA can be 10% or more. Sample O
demonstrates that the etching resistance further decreased when no
IBOA was contained. Sample Q inferior in etching resistance
indicates that the fluorene skeleton acrylate has a large influence
on the etching resistance and is a material necessary to increase
the etching resistance. Sample S shows that the etching resistance
tends to decrease when the content of the polymerization initiator
exceeds 6%. The etching rate increases and the etching resistance
decreases especially when there is neither MADA nor the fluorene
skeleton acrylate and the ratio of the polyfunctional acrylate is
high.
[0181] Samples E, G, P, and S were inferior in separation property
and transfer property. Samples E, G, and H reveal that the content
of the polyfunctional acrylate can be 10% or more. Sample P shows
that problems arise in separation property and transfer property
when there is no IBOA. IBOA was found to be an acrylate required
for mask pattern transfer.
[0182] Samples O and P were inferior in coating property. The
material was seemingly separated in the coating film probably
because the ultraviolet-curable resin contained no IBOA.
[0183] The following processing was performed on samples Q, Y, J,
and W. That is, after the patterns were transferred onto the
ultraviolet-curable resin, RIE using gaseous oxygen was performed
to remove the resist residue from the bottoms of the pattern
recesses. Then, the metal mask layers (Cu) in the portions (the
bottoms of the pattern recesses) from which the resist was removed
were removed by Ar ion milling at a gas pressure of 0.1 Pa for an
etching time of 15 seconds. After that, the carbon protective layer
was removed by RIE using gaseous oxygen, thereby exposing the
surface of the magnetic recording layer. The mask shapes were
measured with an AFM in this state. Consequently, the mask shapes
of samples Q and Y deformed, but samples J and W maintained the
rectangularity of the masks and were able to form micropatterns
having a groove width of about 5 nm. This reveals that when the
ultraviolet-curable resin contains the fluorene skeleton acrylate
and adamantane skeleton acrylate, the mask shape is maintained even
when the magnetic material is processed, and desired patterns and
micropatterns can be processed.
[0184] On the other hand, the surface of the magnetic recording
layer of each of samples Q, Y, J, and W was exposed by removing the
carbon protective layer by RIE using gaseous oxygen following the
same procedures as above, except that gaseous CF.sub.4 milling,
instead of Ar ion milling, was performed at a gas pressure of 0.1
Pa for an etching time of 15 seconds to remove the mask layers (Si)
from the portions (the bottoms of the pattern recesses) from which
the resist was removed. The mask shapes were measured with an AFM
in this state. Consequently, the rectangularity of the masks was
maintained, and it was possible to form micropatterns having a
groove width of about 5 nm. That is, samples J and W according to
the embodiment were able to form good mask shapes regardless of
whether Ar ion milling or gaseous CF.sub.4 milling was used.
However, samples Q and Y containing no fluorene skeleton acrylate
were able to form good mask shapes when using gaseous CF.sub.4
milling, but unable to form good mask shapes when using Ar ion
milling. Recently, the use of gaseous CF.sub.4 is declining greatly
with a view to protecting the environment. Samples Q and Y
containing no fluorene skeleton acrylate were found to have the
environmental problem. In addition, when processing not only the
front side but also the back side of a disk, it is very difficult
to apply reactive ion etching using gaseous CF.sub.4 because
discharge is unstable. A double-sided disk can be processed by Ar
ion milling or Ar sputter etching.
[0185] Furthermore, it was possible to obtain favorable
characteristics when forming DTR media by using good
ultraviolet-curable resin samples B, C, D, F, H, I, J, K, L, M, N,
R, U, V, W, and X, and checking the recording/reproduction
characteristics.
[0186] Note that although Irgacure 369 or Darocur 1173 was used as
the polymerization initiator in this example, it is naturally
possible to appropriately select any polymerization initiator in
accordance with the affinity to the UV lamp or acrylate.
TABLE-US-00001 TABLE 1 Ultraviolet- Fluorene skeleton
Polyfunctional Polymerization curable resin IBOA MADA acrylate
acrylate initiator A 9.4 wt % 0 wt % I45.0 wt % TMPTA 45.1 wt %
IRGACURE369 0.5 wt % B 11.0 wt % 0 wt % I44.9 wt % TMPTA 43.6 wt %
IRGACURE369 0.5 wt % C 44.0 wt % 0 wt % I31.0 wt % TMPTA 24.5 wt %
IRGACURE369 0.5 wt % D 56.4 wt % 0 wt % II18.8 wt % TMPTA 24.1 wt %
IRGACURE369 0.7 wt % E 69.2 wt % 0 wt % I25.4 wt % TMPTA 4.4 wt %
IRGACURE369 0.9 wt % F 61.3 wt % 0 wt % I17.2 wt % TMPTA 20.5 wt %
IRGACURE369 1.0 wt % G 56.3 wt % 0 wt % I38.0 wt % TMPTA 5.1 wt %
IRGACURE369 0.6 wt % H 51.3 wt % 0 wt % I37.3 wt % TMPTA 10.8 wt %
IRGACURE369 0.6 wt % I 27.9 wt % 21.9 wt % I25.1 wt % TMPTA-3EO
24.7 wt % IRGACURE369 0.5 wt % J 26.1 wt % 21.1 wt % I22.8 wt %
TMPTA 29.5 wt % IRGACURE369 0.5 wt % K 10.8 wt % 38.6 wt % I25.2 wt
% TMPTA 24.9 wt % IRGACURE369 0.6 wt % L 29.8 wt % 26.2 wt % I29.1
wt % DTMPTA 14.3 wt % IRGACURE369 0.5 wt % M 27.8 wt % 22.1 wt %
I25.5 wt % GPTA 24.1 wt % IRGACURE369 0.5 wt % N 27.8 wt % 22.1 wt
% I24.8 wt % PE(EO)TTA 24.8 wt % IRGACURE369 0.5 wt %
TABLE-US-00002 TABLE 2 Ultraviolet- Fluorene skeleton
Polyfunctional Polymerization curable resin IBOA MADA acrylate
acrylate initiator O 0 wt % 0 wt % I37.3 wt % HDDA 51.3 wt %/
IRGACURE369 0.6 wt % TMPTA 10.8 wt % P 0 wt % 56.4 wt % I18.8 wt %
TMPTA 24.1 wt % IRGACURE369 0.7 wt % Q 30.2 wt % 29.6 wt % I0 wt %
TMPTA 39.2 wt % IRGACURE369 1.0 wt % R 24.1 wt % 20.1 wt % I22.0 wt
% TMPTA 27.8 wt % DARCUR1173 6.0 wt % S 24.0 wt % 19.9 wt % I22.0
wt % TMPTA 27.6 wt % DARCUR1173 6.5 wt % T 26.2 wt % 21.2 wt %
I22.9 wt % TMPTA 29.7 wt % 0 wt % U 21.5 wt % 21.9 wt % I25.9 wt %
TMPTA 13.1 wt %/ IRGACURE369 0.7 wt % AGDA 16.9 wt % V 56.5 wt % 0
wt % III18.8 wt % TMPTA 24.0 wt % IRGACURE369 0.7 wt % W 27.4 wt %
21.9 wt % I24.9 wt % PU370 25.3 wt % IRGACURE369 0.7 wt % X 27.7 wt
% 22.1 wt % I25.4 wt % SIU2400 24.3 wt % IRGACURE369 0.7 wt % Y
30.0 wt % 0 wt % 0 wt % TMPTA 69.0 wt % IRGACURE369 1.0 wt %
TABLE-US-00003 TABLE 3 Ultraviolet- Curing Separation Coating
Transfer Etching rate curable resin property property property
property (nm/s) A .largecircle. .largecircle. .largecircle.
.largecircle. 0.154 X B .largecircle. .largecircle. .largecircle.
.largecircle. 0.148 .largecircle. C .largecircle. .largecircle.
.largecircle. .largecircle. 0.123 .largecircle. D .largecircle.
.largecircle. .largecircle. .largecircle. 0.129 .largecircle. E
.largecircle. X .largecircle. X 0.084 .largecircle. F .largecircle.
.largecircle. .largecircle. .largecircle. 0.141 .largecircle. G
.largecircle. .DELTA. .largecircle. .DELTA. 0.077 .largecircle. H
.largecircle. .largecircle. .largecircle. .largecircle. 0.086
.largecircle. I .largecircle. .largecircle. .largecircle.
.largecircle. 0.149 .largecircle. J .largecircle. .largecircle.
.largecircle. .largecircle. 0.148 .largecircle. K .largecircle.
.largecircle. .largecircle. .largecircle. 0.129 .largecircle. L
.largecircle. .largecircle. .largecircle. .largecircle. 0.099
.largecircle. M .largecircle. .largecircle. .largecircle.
.largecircle. 0.144 .largecircle. N .largecircle. .largecircle.
.largecircle. .largecircle. 0.147 .largecircle.
TABLE-US-00004 TABLE 4 Ultraviolet- Curing Separation Coating
Transfer Etching rate curable resin property property property
property (nm/s) O .largecircle. .largecircle. X .largecircle. 0.169
X P .largecircle. .DELTA. .DELTA. .DELTA. 0.13 .largecircle. Q
.largecircle. .largecircle. .largecircle. .largecircle. 0.18 X R
.largecircle. .largecircle. .largecircle. .largecircle. 0.149
.largecircle. S .largecircle. .DELTA. .largecircle. .largecircle.
0.156 X T X X X X Immeasurable U .largecircle. .largecircle.
.largecircle. .largecircle. 0.128 .largecircle. V .largecircle.
.largecircle. .largecircle. .largecircle. 0.131 .largecircle. W
.largecircle. .largecircle. .largecircle. .largecircle. 0.149
.largecircle. X .largecircle. .largecircle. .largecircle.
.largecircle. 0.139 .largecircle. Y .largecircle. .largecircle.
.largecircle. .largecircle. 0.215 X
[0187] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the inventions. Indeed, the novel
embodiments described herein may be embodied in a variety of other
forms; furthermore, various omissions, substitutions and changes in
the form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
* * * * *