JP2001323393A - Method for forming fine plating pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for effectively forming various metallic plating patterns required for fine plating for producing a magnetic head with a high precision. SOLUTION: This method for forming fine plating patterns includes a stage (i) in which a first resist pattern capable of feeding acid to the surface of a core substrate as a conductor is formed, a stage (ii) in which a second resist layer which does not dissolve the first resist pattern but makes the same hard to dissolve or insolubilize the same is formed on the outer wall of the first resist pattern, a stage (iii) in which a layer made hard to dissolve or insolubilized is formed on the boundary part between the first resist pattern and the second resist pattern, a stage (iv) in which two layer patterns of the first resist pattern and the layer made hard to dissolve or an insolubilized layer are formed on the second resist pattern, and (v) a stage in which a conductor pattern is adhered and formed with the two layer patterns as masks by plating or electroless plating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a fine plating pattern for forming a fine plating pattern by electroplating or electroless plating by reducing holes or spaces in a resist patterned on a conductive substrate. .

[0002]

2. Description of the Related Art In recent years,
In the field of hard disk drive devices, with the improvement in recording density, there is a demand for a method for forming various metal plating patterns having extremely small line widths of 0.5 μm or less with high precision. Generally, a fine plating pattern is formed by forming a resist pattern by a photolithography technique, and then using the formed resist pattern as a mask, forming a plating film on various base metal films by an electroplating method or an electroless plating method. Later, the resist is removed by etching. That is, in order to form a fine plating pattern, a photolithography technique for obtaining a fine resist pattern is an important key.

In order to achieve the demand for finer resist patterns, high resolution technology requires high NA.
Exposure methods incorporating super-resolution techniques such as a mask technique such as a modified illumination technique and a phase shift method have been studied in response to the trend toward shorter wavelengths.

[0004] On the other hand, with the shortening of the light source wavelength, progress has been made from g-line and i-line novolak materials to materials compatible with the chemical amplification process. There is a limit to the miniaturization of.

In this case, various methods have been proposed as a method for further reducing the space portion or the hole portion of the resist pattern obtained by the conventional exposure technique (JP-A-6-250379, JP-A-6-250379). −134422
JP-A-10-73927, JP-A-11-73927
204399).

However, each of these methods is used as a semiconductor device manufacturing process technology when an underlying semiconductor substrate is etched using the obtained reduced pattern as a mask. Further, in the above method, the first resist film thickness is set to about 1 μm, and it is necessary to increase the degree of freedom up to a resist process having a film thickness of 3 μm or more required in the fine plating forming process in the magnetic head manufacturing process.

The present invention has been made in view of the above circumstances, and particularly in the field of hard disk drive devices.
An object of the present invention is to provide a method for forming an extremely fine plating pattern having a line width interval of 0.5 μm or less.

[0008]

Means for Solving the Problems and Embodiments of the Invention As a result of extensive studies to achieve the above object, the present inventor has found that a thick film type resist pattern formed on a conductive substrate has a semiconductor device manufacturing process. By applying electroplating or electroless plating to fine holes or spaces obtained by applying the technology for reducing the space or hole of the resist pattern in the field of the above, a finer plating pattern can be obtained Is found.

Accordingly, the present invention provides (i) a step of forming a first resist pattern capable of supplying an acid on a conductor core substrate, and (ii) a step of forming a first resist pattern on an outer wall of the first resist pattern. A step of forming a second resist layer that does not dissolve the resist pattern of 1 and is hardly soluble or insoluble in water or an alcoholic aqueous solution due to the presence of an acid;
(Iii) a step of forming a layer insoluble or insoluble in water or an aqueous alcohol solution by heating or exposure at an interface between the first resist pattern and the second resist layer; and (iv) the second resist layer Dissolving a portion to be dissolved by water or an aqueous alcohol solution to form a two-layer pattern including a first resist pattern and the insoluble or insolubilized layer; and (v) electroplating or electroless using the two-layer pattern as a mask. And forming a conductive pattern by plating.

Hereinafter, the present invention will be described in more detail. First step of forming a first resist pattern of the present invention
Is a resist material that generates an acid upon exposure or heating. The acid generated by this exposure or heating generates or promotes a coupling reaction between the polymer compound or the additive in the second resist material described later, and forms a layer insoluble or insolubilized in water or alcohol. Is formed as a coating film covering the outer wall of the resist.

As the first resist material, a chemically amplified resist material containing an acid generator, a chemically changed resist material, or the like is suitably used. In this case, as a chemically amplified resist material, tert well known as a base polymer for a resist material generally used conventionally is well known.
-Butoxycarbonyl group, isopropoxycarbonyl group, tetrahydropyranyl group, trimethylsilyl group, 1
-Ethoxyethyl group, 1-n-propoxyethyl group, 1
-Polyphenol containing an acid labile group such as an isopropoxyethyl group in an amount of 5 to 30 mol% and an acid generator can be used.

Here, as the acid generator,-(p-toluenesulfonyloxyimino) -phenylacetonitrile,-(p-chlorobenzenesulfonyloxyimino)
-Phenylacetonitrile,-(4-nitrobenzenesulfonyloxyimino) -phenylacetonitrile,-
(4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -phenylacetonitrile,-(benzenesulfonyloxyimino) -4-chlorophenylacetonitrile,-(benzenesulfonyloxyimino) -2,4-dichlorophenylacetonitrile,-
(Benzenesulfonyloxyimino) -2,6-dichlorophenylacetonitrile,-(benzenesulfonyloxyimino) -4-methoxyphenylacetonitrile,
-(2-chlorobenzenesulfonyloxyimino) -4
-Methoxyphenylacetonitrile,-(benzenesulfonyloxyimino) -2-thienylphenylacetonitrile,-(4-dodecylbenzenesulfonyloxyimino) -phenylacetonitrile,-(4-toluenesulfonyloxyimino) -4-methoxyphenylacetonitrile,- (4-dodecylbenzenesulfonyloxyimino) -4-methoxyphenylacetonitrile,-
An oxime sulfonate compound such as (4-toluenesulfonyloxyimino) -3-thienylacetonitrile, diphenyliodonium trifluoromethanesulfonate,
Trifluoromethanesulfonic acid (p-tert-butoxyphenyl) iodonium, p-toluenesulfonic acid diphenyliodonium, p-toluenesulfonic acid (p-
tert-butoxyphenyl) iodonium, triphenylsulfonium trifluoromethanesulfonate, trifluoromethanesulfonic acid (p-tert-butoxyphenyl) diphenylsulfonium, bis (p-tert-butoxyphenyl) phenylsulfonium trifluoromethanesulfonate, trifluoromethanesulfonic acid Tris (p-tert-butoxyphenyl) sulfonium, triphenylsulfonium p-toluenesulfonate, diphenylsulfonium p-toluenesulfonate (p-tert-butoxyphenyl), bis (p-tert-butoxyphenyl) p-toluenesulfonate Phenylsulfonium, tris-p-toluenesulfonate (p-
tert-butoxyphenyl) sulfonium, triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfonium butanesulfonate, trimethylsulfonium trifluoromethanesulfonate, trimethylsulfonium p-toluenesulfonate, cyclohexylmethyl trifluoromethanesulfonate (2-oxocyclohexyl) Sulfonium, cyclohexylmethyl p-toluenesulfonate (2-oxocyclohexyl) sulfonium, dimethylphenylsulfonium trifluoromethanesulfonate, dimethylphenylsulfonium p-toluenesulfonate, dicyclohexylphenylsulfonium trifluoromethanesulfonate, dicyclohexylphenylsulfonium p-toluenesulfonate Onium salts such as B hexylcarbonyl-2-(p-
-Ketosulfone derivatives such as toluenesulfonyl) propane and 2-isopropylcarbonyl-2- (p-toluenesulfonyl) propane; diazomethanes such as bis (benzenesulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane and bis (tert-butylsulfonyl) diazomethane Derivatives, diphenyldisulfone,
Disulfone derivatives such as dicyclohexyldisulfone,
Sulfonate derivatives such as 1,2,3-tris (methanesulfonyloxy) benzene, 1,2,3-tris (trifluoromethanesulfonyloxy) benzene, and 1,2,3-tris (p-toluenesulfonyloxy) benzene Phthalimido-yl-triflate, phthalimido-yl-tosylate, 5-norbornene-2,3-
Dicarboximido-yl-triflate, 5-norbornene-2,3-dicarboximido-yl-tosylate, 5-norbornen-2,3-dicarboximide-
Imido-yl-sulfonate derivatives such as yl-n-butylsulfonate, 2,4,6-tris (trichloromethyl) -S-triazine, 2,4,6-tris (tribromomethyl) -S-triazine, One or more kinds of halomethylated triazine compounds such as 4-bis (trichloromethyl) -6-p-trimethoxyphenyl-S-triazine can be used. The amount of the acid generator is preferably 1 to 8 parts by weight, particularly preferably 1 to 5 parts by weight based on 100 parts by weight of the base polymer (polyvinyl phenol derivative).

As a first resist material, a novolak resin having a weight-average molecular weight in the range of 2,000 to 20,000 is prepared by adding a hydrogen atom of a phenolic hydroxyl group to a 1,2-naphthoquinonediazidosulfonyl group in an amount of 2 to 50 mol%. A substituted photosensitive group-integrated cresol-novolak resin, o-naphthoquinonediazide-5-sulfonic acid ester of tri- or tetrahydroxybenzophenone with cresol-novolak resin or o-naphthoquinonediazide-4-sulfonic acid ester (substitution ratio 50 to 100, respectively) (% By mol) of a two-component composition containing a naphthoquinonediazide-based photosensitizer, and a resist material in which the above-mentioned acid generator is mixed with a chemically-changeable resist. In this case, the compounding amount of the acid generator is 0.1 to 100 parts by weight of the base polymer (cresol-novolak derivative).
It is preferably from 10 to 10 parts by weight, particularly preferably from 0.2 to 5 parts by weight.

As the first resist material, after pattern formation, a second resist material, a layer insoluble or insolubilized in water or an aqueous alcohol solution by heating or exposure to an interface portion between the first and second resist layers. Forming the second
It must be insoluble in water or an alcohol aqueous solution used for dissolving the water or alcohol aqueous solution-soluble portion of the resist layer, and also in a plating solution used for applying a fine plating pattern.

The conductor and the fine plating metal in the step of forming the first resist pattern include iron, nickel, cobalt or alloys thereof, copper, gold and the like which are usually used for the magnetic head core.

Next, the resist material for forming the second resist layer used in the present invention contains a water-soluble polymer compound and, if necessary, a crosslinking agent.

Examples of the water-soluble polymer compound include polyvinyl alcohol having a weight average molecular weight of 2,000 to 100,000, water-soluble cellulose ether, polyacrylic acid, polyvinyl acetal, polyvinyl pyrrolidone, polyethylene imine, polyethylene oxide, styrene-maleic anhydride. One or a mixture of two or more of an acid copolymer, polyvinylamine, polyallylamine, and an oxazoline group-containing water-soluble resin may be used. In addition to the water-soluble polymer compound, a water-soluble polymer compound which is a copolymer of two or more of the water-soluble polymer compounds is also used.

In the resist material for forming the second resist layer, as a cross-linking agent for performing a coupling reaction with a water-soluble polymer compound, amino resin derivatives such as melamine derivatives, urea derivatives and glycoluril derivatives are used. One or a mixture of two or more of the above is preferably used.

The resist material for forming the second resist layer is made of a water-soluble plasticizer such as ethylene glycol or a product of 3M Co., Ltd. A water-soluble surfactant such as Florard can be added.

The solvent used for the resist material for forming the second resist layer does not dissolve the resist pattern,
There is no particular limitation as long as it dissolves a water-soluble polymer as a binder. Specifically, pure water, a mixed solvent of pure water and an alcohol such as methanol, ethanol and isopropyl alcohol, pure water and γ-butyrolactone or N-
A mixed solvent of a water-soluble organic solvent such as methylpyrrolidone, and a mixed solvent of pure water, an alcohol, and γ-butyrolactone or N-methylpyrrolidone are used.

In the method of forming a fine plating pattern according to the present invention, a commonly used general resist process can be applied as the first resist pattern forming method.
That is, after the first resist material is applied on the core substrate of the conductor by spin coating or the like, 70 to 130
Pre-baking is performed at a temperature of ℃, exposure is performed using a light source applied to the resist material such as g-ray, i-ray, far ultraviolet ray, electron beam, X-ray, and, if necessary, post-exposure baking is performed at a temperature of 60 to 120 ° C. Next, development is performed using a tetramethylammonium hydroxide aqueous solution or the like, and FIG.
As shown in (A), a conductor core substrate (conductor substrate) 1
A first resist pattern 2 of a first resist material is formed thereon.

Next, as shown in FIG. 1B, a conductor core substrate 1 patterned with the first resist material is used.
A second resist material is applied thereon. The method of applying the second resist material is not particularly limited as long as it can be uniformly applied on the first resist pattern, and can be applied by a spray coating method, a spin coating method, a dip method, or the like. After applying the second resist material, a pre-bake is performed at 60 to 100 ° C. as necessary to form a second resist layer 3.

Thereafter, the first and second resist patterns on the conductive substrate are subjected to a heat treatment at 100 to 150 ° C.
“Mixing bake”), and then the supply of acid from the first resist pattern was promoted, as shown in FIG.
At the interface between the first resist pattern 2 and the second resist layer 3, a layer 4 that is hardly soluble or insoluble in an aqueous solution of water or alcohol is formed. The mixing baking condition in this case is preferably performed at 100 to 150 ° C. for 60 to 200 seconds, and can be appropriately set depending on the type of the resist material used and the required thickness of the insolubilized layer.

Next, as shown in FIG. 1D, the dissolving layer (the second resist layer 3 other than the hardly soluble or insolubilized layer 4) is removed using water or an aqueous alcohol solution. A two-layer resist pattern having a hardly soluble or insolubilized layer 4 on the outer wall of the first resist pattern 2 is obtained.

By the above processing, it is possible to obtain a line and space pattern or an isolated pattern with a reduced space width.

The pattern forming method of the present invention can be carried out by supplying an acid by exposure in addition to the above-mentioned method. In this case, the steps from patterning using the first resist to applying the second resist material and forming the second resist layer are the same as the above-described methods, but instead of the next mixing bake, or The acid is supplied from the first resist pattern by performing exposure again as it is before the mixing bake. The light source that can be used at this time is the same as the light source used when patterning the first resist material, and is not particularly limited as long as it generates an acid upon exposure. Further, if necessary, the supply of acid from the first resist pattern to the second resist layer is promoted by mixing and baking, and an insolubilized layer for water or an aqueous alcohol solution is formed at the interface with the second resist layer. The mixing baking conditions in this case are the same as described above, and can be appropriately set according to the type of the resist material used and the required thickness of the insolubilized layer. Then, similarly to the above, the dissolved layer is removed with water or an aqueous alcohol solution to obtain a first resist pattern having a hardly soluble or insoluble layer on the outer wall.

Thereafter, as shown in FIG. 1E, a plating layer 5 is formed by electroplating or electroless plating the space and the like not masked by the resist. in this case,
Examples of the plating metal include iron, nickel, cobalt or alloys thereof, copper, and gold, as described above, but are not limited thereto. Electroplating and electroless plating can be performed according to a conventional method.

Finally, the fine pattern 6 of the plating layer 5 as shown in FIG. 1 (F) is formed by removing the resist layer by etching.

Here, the thickness of the resist layer is preferably 3 μm or more, particularly 3 to 20 μm, more preferably 4 to 10 μm, and the line width interval is 0.5 μm or less, particularly 0.05 to 0 μm. 0.5 μm, more preferably 0.1
To 0.4 μm, and according to the present invention,
It is suitably employed when obtaining such a fine plating pattern.

[0030]

According to the present invention, particularly in a resist process having a film thickness of 3 μm or more, which is required in the fine plating process in the magnetic head manufacturing process, the line width is set to 0.5 μm.
This is effective as a method for forming various metal plating patterns having a very small size of m or less with high precision.

[0031]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.

Example 1 Poly- (p-hydroxystyrene) (Mw = 10000, Mw / Mn = 1.05)
A base polymer (35 parts by weight) into which 12 mol% of a tert-butylcarbonyloxy group was introduced as an acid labile group, and diphenyldiazomethane (1.5%) as an acid generator.
Parts by weight) was dissolved in propylene glycol monomethyl ether acetate (65 parts by weight) to prepare a first resist material.

Next, this resist material was applied on a substrate obtained by sputtering an Fe film on a 6-inch silicon wafer by using a spinner, and then heated on a hot plate at 120 ° C.
Prebaking for 120 seconds to form a resist film having a thickness of 6.0 μm, and exposing using a KrF excimer laser stepper (Nikon NSR-2005Ex8A, NA = 0.5), followed by post-exposure baking (10
0 ° C., 120 seconds), and then developed with a 2.38% by weight aqueous solution of tetraammonium hydroxide.
After rinsing with pure water, a first resist pattern having a 0.45 μm line & space pattern and a 0.45 μm isolated space pattern was obtained.

On the first resist pattern, 10 g of polyvinyl alcohol having a saponification degree of 88 mol% and pure water 80
g, 10 g of isopropyl alcohol at room temperature for 6 hours with stirring to obtain a second resist material at 3000 rpm.
After spin coating, pre-bake (9 at 85 ° C).
0 second) to form a second resist layer.

Next, a mask aligner (PL manufactured by Canon Inc.)
A600F), followed by mixing baking (110 ° C. for 120 seconds) to form a water-insoluble layer at the interface between the first resist pattern and the second resist layer, followed by 50 seconds of pure water The water solubilized layer was removed with a paddle. Subsequently, the hardly-solubilized layer was fixed by performing post-baking (at 110 ° C. for 120 seconds). As a result of observation by an electron microscope, a 0.03 μm hardly-solubilized layer was formed.
Both the 45 μm line & space pattern and the 0.45 μm isolated space pattern were 0.39 μm space patterns. Next, wet etching was performed with a 3% sulfuric acid aqueous solution, immersion in an iron plating solution and electroplating for a predetermined time, and then the resist was stripped with a stripping solution to obtain a plating pattern.

Example 2 m, p as base polymer
A novolak resin (36 parts by weight) in which 8 mol% of the hydrogen atoms of the hydroxyl group of the cresol-based novolak resin (Mw = 7,900) has been substituted with a 1,2-naphthoquinonediazidosulfonyl ester group; 6-Tris (trichloromethyl) -1,3,5-triazine (2 parts by weight) was dissolved in ethyl lactate (62 parts by weight) to prepare a first resist material.

Next, this resist material is applied on a substrate obtained by sputtering a Ni film on a 6-inch silicon wafer by using a spinner, and is then coated on a hot plate by 100 μm.
Prebaked at 120 ° C. for 120 seconds to form a resist film having a thickness of 6.0 μm, and an i-line stepper (Nikon NSR-1)
755i7, NA = 0.5), developed, rinsed with pure water, and sputtered with a Ni film on a 6-inch silicon wafer. A 0.5 μm line & space pattern, 0.5 μm isolated Space pattern was obtained.

On the first resist pattern, 10 g of polyvinyl acetal, 90 g of pure water and 3 g of dihydroxymethyl urea were added, and a second resist material obtained by stirring and mixing at room temperature for 6 hours was spin-coated at 3000 rpm. Thereafter, prebaking (at 80 ° C. for 90 seconds) was performed to form a second resist material layer.

Next, a mask aligner (PL manufactured by Canon Inc.)
A600F), followed by mixing baking (110 ° C. for 120 seconds) to form a layer hardly soluble in an aqueous alcohol solution at the interface between the first resist pattern and the second resist layer. The mixture was treated with an aqueous solution for 50 seconds and further with a pure water paddle for 50 seconds to remove an alcohol aqueous solution soluble layer. Subsequently, the hardly-solubilized layer was fixed by performing post-baking (110 ° C., 120 seconds). Observation with an electron microscope revealed that
An insoluble layer of 04 μm was formed, and the 0.5 μm line & space pattern and the 0.5 μm isolated space pattern were all 0.42 μm space patterns. Next, wet etching was performed with a 3% sulfuric acid aqueous solution, immersion in an electroless Ni plating solution, electroless plating at a predetermined temperature for a predetermined time, and then stripping solution resist was stripped to obtain a plating pattern.

Example 3 A first resist pattern was obtained in the same manner as in Example 1 by using the same first resist material as in Example 1, and then hydroxypropyl was formed on the first resist pattern. 5 g of methylcellulose, 90 g of pure water,
10 g of isopropyl alcohol and 3 g of tetrahydroxymethyl glycoluril were added, and the mixture was stirred and mixed at room temperature for 6 hours to obtain a second resist material at 3000 rpm.
After spin coating, pre-bake (90 ° C, 9
0 second) to form a second resist layer.

Next, mixing baking (12 hours at 110 ° C.)
0 second) to form an insoluble layer in an aqueous alcohol solution at the interface between the first resist pattern and the second resist layer.
The solution was further treated for 50 seconds with a pure water paddle for 50 seconds to remove the aqueous solution soluble layer. Subsequently, the hardly-solubilized layer was fixed by performing post-baking (at 110 ° C. for 120 seconds).
As a result of observation by an electron microscope, a hardly-solubilized layer of about 0.04 μm was formed, and a 0.45 μm line & space pattern and a 0.45 μm isolated space pattern each became a 0.38 μm space pattern. Next, Example 1
A plating pattern was obtained in the same manner as described above.

[Brief description of the drawings]

FIGS. 1A and 1B illustrate a method of the present invention, in which FIG. 1A is a cross-sectional view showing a state in which a first resist pattern is formed on a conductive substrate;
(B) is a sectional view showing a state where a second resist layer is formed,
(C) is a cross-sectional view showing a state in which a hardly-solubilized or insolubilized layer is formed at the interface between the first resist pattern and the second resist layer. (D) is a cross-sectional view of the second resist layer excluding the hardly-solubilized or insolubilized layer portion. FIG. 4E is a cross-sectional view of a state where a plating layer is formed in a space portion, and FIG. 4F is a cross-sectional view of a plating pattern from which a resist has been removed.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductor substrate 2 first resist pattern 3 second resist layer 4 insoluble or insolubilized layer 5 plating layer 6 plating pattern

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Ueda 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture F-term in Shin-Etsu Chemical Co., Ltd. Silicone Electronics Materials Research Laboratory 4K022 AA02 AA44 BA03 BA06 BA08 BA09 BA14 BA31 BA32 BA35 CA08 CA26 DA01 4K024 AA01 AA03 AA09 AA11 AA14 AB01 AB15 BA01 BA11 BB09 BB14 BC10 FA07 FA08 GA07 5D033 DA04 DA09 DA31

Claims (1)

[Claims] (I) forming a first resist pattern capable of supplying an acid on a conductor core substrate; and (ii) forming a first resist pattern on an outer wall of the first resist pattern. Forming a second resist layer that does not dissolve and that is hardly soluble or insoluble in water or an alcoholic aqueous solution due to the presence of an acid; and (iii) a first resist layer.
At the interface between the resist pattern and the second resist layer,
Forming a layer insoluble or insolubilized in water or an aqueous alcohol solution by heating or exposure; and (iv) a second step.
Dissolving a portion of the resist layer dissolved in water or an aqueous alcohol solution to form a two-layer pattern including a first resist pattern and the insolubilized or insolubilized layer; and (v) masking the two-layer pattern. Forming a conductive pattern by electroplating or electroless plating.