JP3218349U - Resist layer thinning device - Google Patents

Abstract

A resist layer thinning apparatus capable of solving the problem of processing unevenness caused by bubbles, which is a problem in thinning processing of a resist layer, while solving the problems of resolution and followability in forming a resist pattern provide. A dip tank for thinning a resist layer with an alkaline aqueous solution, and a pair of conveyance rolls for conveying a substrate on which the resist layer is formed while being immersed in the alkaline aqueous solution. The thinning process of the resist layer comprising the alkaline aqueous solution supply port 11 for supplying the alkaline aqueous solution 9 to the dip tank 10 and the bubble guide plate 16 provided between the alkaline aqueous solution supply port 11 and the transport roll pair 12 In the apparatus, the bubble guide plate 16 has irregularities. [Selection] Figure 8

Description

  The present invention relates to an apparatus for thinning a resist layer.

  As electrical and electronic components become smaller, lighter, and multifunctional, photosensitive resin (photosensitive materials) such as dry film resists and solder resists for circuit formation will increase the density of printed wiring boards. In order to respond, high resolution is required. Image formation with these photosensitive resins is performed by developing the photosensitive resin after exposure.

  In order to cope with the miniaturization and high functionality of the printed wiring board, the photosensitive resin tends to be thinned. The photosensitive resin includes a liquid resist of a type used by applying a liquid and a dry film resist of a dry film type. Recently, dry film resists with a thickness of 15 μm or less have been developed and commercialized. However, such a thin dry film resist has a problem in that it has insufficient adhesion and followability to unevenness as compared with a resist having a conventional thickness, and peeling or voids are generated.

  In order to solve these problems, means for achieving high resolution while using a thick photosensitive resin has been proposed. For example, in a method for producing a conductive pattern by a subtractive method, after forming a resist layer by attaching a dry film resist for an etching resist on a laminated substrate in which a metal layer is provided on one or both sides of an insulating layer, A method for forming a conductive pattern is disclosed in which a resist layer thinning step is performed, and then a circuit pattern exposure step, a development step, and an etching step are performed (see, for example, Patent Document 1). In the method of forming a solder resist pattern, after forming a resist layer made of a solder resist on a circuit board having a conductive pattern, a resist layer thinning step is performed, then a pattern exposure step is performed, and the resist is again formed. A method for forming a solder resist pattern characterized by performing a layer thinning process is disclosed (for example, see Patent Documents 2 and 3).

  The thinning step is a micellization process (thinning process) in which the photo-crosslinkable resin component of the resist layer in the unexposed portion is micellized using an alkaline aqueous solution, a micelle removal process for removing micelles with an alkaline aqueous solution of pH 5-9, It includes at least four stages of water washing treatment for washing the surface with water and drying treatment for removing washing water. The progress of thinning is controlled by the processing time in the thinning process with an alkaline aqueous solution. However, when bubbles exist in the aqueous alkali solution and the bubbles come into contact with the photocrosslinkable resin component of the resist layer in the unexposed area, there is a problem that the progress of thinning of the portion where the bubbles are in contact is prevented. To do. Since the resist layer remains thick in the area where the progress of thinning is hindered, the conductive pattern formation in the subtractive method causes etching failure, and in the solder resist pattern formation, the contact pad portion contact failure This causes problems that both lead to a decrease in production yield.

  Furthermore, after the exposure process, through the thinning process including the thinning process of the resist layer with the alkaline aqueous solution, the exposure process is performed again, and then the thinning process including the thinning process of the resist layer with the alkaline aqueous solution is performed again, Inhibition of thinning due to contact of bubbles with the resist layer becomes more serious. When the resist layer in the unexposed area is thinned in steps by repeating the exposure process and the thinning process, bubbles are likely to remain in the stepped part formed at the boundary between the exposed area and the unexposed area of the resist layer. Then, the thinning of the resist layer at the portion where the bubbles are in contact is hindered thereafter. For example, when the thinning process including the exposure process and the thinning process is repeated twice, when the second thinning part is the same as or inside the first thinning part, the second time During the thinning process, bubbles tend to remain inside the step formed at the boundary between the first exposed portion and the first thinned portion.

  Patent Document 4 discloses a thinning apparatus for thinning a resist layer by immersing (dip) the substrate on which the resist layer is formed in a thinning solution (alkaline aqueous solution). . A thinning device disclosed in Patent Document 4 will be described with reference to the drawings. 5 and 6 are schematic cross-sectional views of the thin film forming apparatus described in Patent Document 4. FIG. FIG. 5 is a schematic cross-sectional view seen from a direction (CD direction) orthogonal to the substrate transport direction (MD direction), and FIG. 6 is a schematic cross-sectional view seen from the substrate transport direction (MD direction). In this thin film forming apparatus, the substrate 8 on which the resist layer is formed is transported while being immersed in the alkaline aqueous solution 9 in the dip tank 10 by the transport roll pair 12, and the resist layer is thinned. The alkaline aqueous solution 9 is supplied from the alkaline aqueous solution storage tank 13 at the lower part of the apparatus to the dip tank 10 through the alkaline aqueous solution supply port 11 by the alkaline aqueous solution supply pump 14 and overflows. The overflowed alkaline aqueous solution 9 is recovered in the alkaline aqueous solution recovery tank 30, discharged from the recovery tube discharge port 22 through the recovery tube 21, and stored in the alkaline aqueous solution storage tank 13. By repeating this, the alkaline aqueous solution 9 circulates between the dip tank 10 and the alkaline aqueous solution storage tank 13.

  In the thin film forming apparatus shown in FIGS. 5 and 6, when the alkaline aqueous solution 9 is circulated, when the alkaline aqueous solution 9 falls from the dip tank 10 to the alkaline aqueous solution storage tank 13 due to overflow, bubbles 15 are contained in the alkaline aqueous solution 9. The bubbles 15 may adhere to the resist layer of the substrate 8 due to the circulation of the alkaline aqueous solution 9 and inhibit the progress of thinning, resulting in processing unevenness in which the film thickness becomes uneven (spots). It was.

  In order to solve the problem of processing unevenness caused by the bubbles 15, a resist layer thinning device including a bubble guide plate 16 provided between the alkaline aqueous solution supply port 11 and the transport roll pair 12 is disclosed. (For example, refer to Patent Document 5). The thinning device disclosed in Patent Document 5 will be described with reference to the drawings. 7 and 8 are schematic cross-sectional views of the thinning device described in Patent Document 5. FIG. FIG. 8 is a schematic cross-sectional view seen from the CD direction, and FIG. 8 is a schematic cross-sectional view seen from the MD direction. In the thin film forming apparatus shown in FIGS. 7 and 8, a bubble guide plate 16 is installed between the alkaline aqueous solution supply port 11 and the transport roll pair 12. By the bubble guide plate 16, the bubbles 15 generated in the alkaline aqueous solution circulation process in the thin film forming device are guided to the outer region in the width direction of the thin film forming device than the substrate 8 on which the resist layer being thinned is formed. It can prevent adhering to the board | substrate 8 with which the resist layer in it was formed.

  However, even if the bubbles 15 are induced by the bubble guide plate 16 in the outer region in the width direction of the thin film forming device than the substrate 8 on which the resist layer being thinned is formed, the liquid temperature of the alkaline aqueous solution 9 is low. In the case where the concentration of the alkaline aqueous solution 9 is high and the viscosity is high, the extremely small bubbles 15 do not escape immediately into the air but float in the alkaline aqueous solution 9 as they are, and the flow of the alkaline aqueous solution 9 in the dip tank 10 Then, heading toward the substrate 8 and processing unevenness may occur.

International Publication No. 2009/096438 Pamphlet JP 2011-192692 A International Publication No. 2012/043201 Pamphlet JP 2012-27299 A Utility Model Registration No. 3182371

  The subject of this invention is the resist which can solve the problem of the process nonuniformity by a bubble in the thinning apparatus of the resist layer used with the formation method of the resist pattern which can solve the problem of resolution and followability It is to provide a layer thinning device.

  The above problem can be solved by the following means.

  A dipping bath for thinning the resist layer with an aqueous alkali solution, a pair of transport rolls for transporting the substrate on which the resist layer is formed while being immersed in the aqueous alkaline solution, and supplying the aqueous alkaline solution to the dipping bath In a resist layer thinning apparatus comprising an alkaline aqueous solution supply port, and a bubble guide plate provided between the alkaline aqueous solution supply port and a pair of transport rolls, the bubble guide plate has irregularities. Resist layer thinning device.

  According to the present invention, it is possible to provide a resist layer thinning device that can solve the problem of uneven processing due to bubbles.

It is sectional process drawing showing an example of the formation method of the resist pattern performed using the thin film forming apparatus of the resist layer of this invention. It is sectional process drawing showing an example of the formation method of the resist pattern performed using the thin film forming apparatus of the resist layer of this invention. It is sectional process drawing showing an example of the formation method of the resist pattern performed using the thin film forming apparatus of the resist layer of this invention. It is sectional process drawing showing an example of the formation method of the resist pattern performed using the thin film forming apparatus of the resist layer of this invention. It is a schematic sectional drawing which shows the thin film forming apparatus by a prior art. It is a schematic sectional drawing which shows the thin film forming apparatus by a prior art. It is a schematic sectional drawing which shows an example of the thin film forming apparatus provided with a bubble guide plate. It is a schematic sectional drawing which shows an example of the thin film forming apparatus provided with a bubble guide plate. It is a schematic enlarged view which shows an example of a bubble guide plate. It is a schematic enlarged view which shows an example of a bubble guide plate.

  The resist layer thinning apparatus of the present invention will be described in detail below.

  A method of forming a resist pattern performed using the resist layer thinning apparatus of the present invention will be described with reference to FIGS.

  A resist pattern forming method (1) in the case of forming a conductive pattern by a subtractive method will be described with reference to FIG.

[FIG. 1a] A laminated substrate in which a metal layer 7 is provided on an insulating layer 1 is prepared.
[FIG. 1b] An alkali developing type resist layer 3 is formed on the laminated substrate.
[FIG. 1c] The resist layer 3 is thinned with an alkaline aqueous solution while suppressing bubbles from adhering to the resist layer 3 (thinning step).
[FIG. 1d] The resist layer 3 having a reduced thickness is subjected to pattern exposure with actinic rays 5 (exposure process).
[FIG. 1e] The resist layer 3 in the unexposed area is removed by development (development process).

  This makes it possible to form a resist pattern having no unevenness in thinning due to bubbles, as shown in FIG. 1e. After FIG. 1e, a conductive pattern is obtained by etching the metal layer 7 not covered with the resist pattern in the etching step.

  A resist pattern forming method (2) using a solder resist will be described with reference to FIG.

[FIG. 2a] A circuit board having conductor wiring 2 and connection pads 6 formed on an insulating layer 1 is prepared. [FIG. 2b] An alkali developing type resist layer 3 is formed on the circuit board.
[FIG. 2c] A portion of the resist layer 3 other than the region to be thinned is exposed with actinic rays 5 (exposure step).
[FIG. 2d] While suppressing the bubble from adhering to the resist layer 3, the resist layer 3 in the unexposed portion is thinned with an alkaline aqueous solution until the thickness of the resist layer 3 becomes thinner than the thickness of the connection pad 6 (see FIG. Thinning process).

  As a result, as shown in FIG. 2 d, the conductive wiring 2 is covered with the resist layer 3 without the unevenness of the thinning process due to bubbles, and the connection pad 6 forms a multi-stage resist pattern exposed from the resist layer 3. be able to.

  A resist pattern forming method (3) in the case of forming a conductive pattern by a subtractive method will be described with reference to FIG.

[FIG. 3a] A laminated substrate in which the metal layer 7 is provided on the insulating layer 1 is prepared.
[FIG. 3b] An alkali developing resist layer 3 is formed on the laminated substrate.
[FIG. 3c] A portion of the resist layer 3 other than the region to be thinned is exposed with actinic rays 5 (first exposure step).
[FIG. 3d] The resist layer 3 in an unexposed portion is thinned with an alkaline aqueous solution while suppressing bubbles from adhering to the resist layer 3 (thinning step).
[FIG. 3e] A portion of the resist layer 3 other than the region to be developed is exposed with actinic rays 5 (second exposure step).
[FIG. 3f] The resist layer 3 in the unexposed area is removed by development (development process).

  As a result, a resist pattern having a multi-stage structure can be formed, as shown in FIG. Next, in the etching step, the conductive layer is obtained by etching the metal layer 7 not covered with the resist pattern.

  A method (4) for forming a resist pattern using a solder resist will be described with reference to FIG.

[FIG. 4a] A circuit board having conductor wiring 2 and connection pads 6 formed on an insulating layer 1 is prepared.
[FIG. 4b] An alkali developing resist layer 3 is formed on the circuit board.
[FIG. 4c] A portion of the resist layer 3 other than the region to be thinned for the first time is exposed with actinic rays 5 (first exposure step).
[FIG. 4d] While suppressing bubbles from adhering to the resist layer 3, the resist layer 3 in the unexposed area is thinned with an alkaline aqueous solution until the thickness of the resist layer 3 becomes equal to or greater than the thickness of the connection pad 6 (first time). Thinning process).
[FIG. 4e] A portion of the resist layer 3 other than the region to be thinned a second time is exposed with actinic rays 5 (second exposure step).
[FIG. 4f] While suppressing the bubble from adhering to the resist layer 3, the unexposed portion of the resist layer 3 is thinned with an alkaline aqueous solution until the thickness of the resist layer 3 becomes thinner than the thickness of the connection pad 6 (2 Second thinning process).

  As a result, as shown in FIG. 4 f, the conductive wiring 2 is covered with the resist layer 3 and the connection pad 6 can form a resist pattern having a multistage structure exposed from the resist layer 3 without any unevenness of the thinning process due to bubbles. .

  Examples of the substrate include a printed wiring board substrate, a lead frame substrate; a circuit board obtained by processing a printed wiring board substrate and a lead frame substrate.

  Examples of the printed wiring board substrate include a flexible substrate and a rigid substrate. The thickness of the insulating layer of the flexible substrate is 5 to 125 μm, and a metal substrate of 1 to 35 μm is provided on both sides or one side to form a laminated substrate, and the flexibility is high. As the material for the insulating layer, polyimide, polyamide, polyphenylene sulfide, polyethylene terephthalate, liquid crystal polymer, or the like is usually used. A material having a metal layer on an insulating layer is a thin conductive layer having a thickness of several nm formed on a resin film by an adhesion method in which an adhesive is bonded, a casting method in which a resin liquid is applied on a metal foil, or a sputtering or vapor deposition method. A material produced by any method such as a sputtering / plating method in which a metal layer is formed by electrolytic plating on the (seed layer), or a laminating method in which the metal layer is attached by hot pressing may be used. As the metal of the metal layer, any metal such as copper, aluminum, silver, nickel, chromium, or an alloy thereof can be used, but copper is generally used.

  A rigid substrate is made by stacking an insulating substrate in which an epoxy resin or phenolic resin is immersed in a paper base or glass base to form an insulating layer, and a metal foil is placed on one or both sides of the base and laminated by heating and pressing. And a laminated substrate provided with a metal layer. Moreover, the multilayer board which has a through-hole and a non-through-hole, and the multilayer shield board produced by laminating | stacking a prepreg, metal foil, etc. after an inner layer wiring pattern process is also mentioned. The thickness is 60 μm to 3.2 mm, and the material and thickness thereof are selected according to the final use form as a printed wiring board. Examples of the material for the metal layer include copper, aluminum, silver, and gold, but copper is the most common. Examples of these printed wiring board substrates include "Printed Circuit Technology Handbook-Second Edition" (edited by the Japan Society of Printed Circuits, published in 1987, published by Nikkan Kogyo Shimbun) and "Multilayer Printed Circuit Handbook" (JA). Scarlet, 1992, published by Modern Chemical Co., Ltd.).

  Examples of the lead frame substrate include iron nickel alloy and copper alloy substrates.

  A circuit board is a board | substrate with which the connection pad for connecting electronic components, such as a semiconductor chip which consists of metals, such as copper, was formed on the insulating board | substrate. Conductor wiring may be formed. Examples of the method for producing the circuit board include a subtractive method, a semi-additive method, and an additive method. In the subtractive method, for example, an etching resist pattern is formed on the above printed wiring board substrate, and an exposure process, a development process, an etching process, and a resist stripping process are performed to produce a circuit board.

  As the resist, an alkali developing resist can be used. Further, it may be a liquid resist or a dry film resist, and can be thinned with an alkaline aqueous solution (thinning treatment liquid) and by a developing solution that is an alkaline aqueous solution having a lower concentration than the thinning treatment liquid. Any resist that can be developed can be used. The alkali development type resist contains a photocrosslinkable resin component. The photocrosslinkable resin component contains, for example, an alkali-soluble resin, a photopolymerizable compound, a photopolymerization initiator, and the like. Moreover, you may contain an epoxy resin, a thermosetting agent, an inorganic filler, etc.

  Examples of the alkali-soluble resin include organic polymers such as acrylic resins, methacrylic resins, styrene resins, epoxy resins, amide resins, amide epoxy resins, alkyd resins, and phenol resins. Among these, it is preferable that it is a thing obtained by superposing | polymerizing (radical polymerization etc.) the monomer (polymerizable monomer) which has an ethylenically unsaturated double bond. These polymers soluble in an alkaline aqueous solution may be used alone or in combination of two or more. Examples of the monomer having such an ethylenically unsaturated double bond include styrene, vinyltoluene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, p-methoxystyrene, and p-ethoxystyrene. Styrene derivatives such as p-chlorostyrene and p-bromostyrene; acrylamide such as diacetone acrylamide; acrylonitrile; esters of vinyl alcohol such as vinyl-n-butyl ether; (meth) acrylic acid alkyl ester; (meth) acrylic acid Tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) acrylic acid diethylaminoethyl ester, (meth) acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth) acrylate, 2,2, 3,3-te Rafluoropropyl (meth) acrylate, (meth) acrylic acid, α-bromo (meth) acrylic acid, α-chloro (meth) acrylic acid, β-furyl (meth) acrylic acid, β-styryl (meth) acrylic acid, etc. (Meth) acrylic acid monoesters; maleic monomers such as maleic acid, maleic anhydride, monomethyl maleate, monoethyl maleate, monoisopropyl maleate; fumaric acid, cinnamic acid, α-cyanocinnamic acid , Itaconic acid, crotonic acid, propiolic acid and the like.

  Examples of the photopolymerizable compound include a compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid; a bisphenol A (meth) acrylate compound; a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid. Compound obtained by reacting acid; Urethane monomer such as (meth) acrylate compound having urethane bond in molecule; Nonylphenoxypolyethyleneoxyacrylate; γ-chloro-β-hydroxypropyl-β '-(meth) acryloyloxyethyl Phthalic acid compounds such as -o-phthalate, β-hydroxyalkyl-β '-(meth) acryloyloxyalkyl-o-phthalate; (meth) acrylic acid alkyl ester, EO, PO-modified nonylphenyl (meth) acrylate, etc. Can be mentioned. Here, EO and PO represent ethylene oxide and propylene oxide, the EO-modified compound has a block structure of ethylene oxide group, and the PO-modified compound has a block structure of propylene oxide group. Is. These photopolymerizable compounds can be used alone or in combination of two or more.

  Examples of the photopolymerization initiator include benzophenone, N, N'-tetramethyl-4,4'-diaminobenzophenone (Michler ketone), N, N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'- Such as dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1, etc. Aromatic ketone; 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1 -Chloroanthraquinone, 2-me Quinones such as luanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, 2,3-dimethylanthraquinone; benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether Benzoin ether compounds such as benzoin, benzoin compounds such as benzoin, methylbenzoin, and ethylbenzoin; benzyl derivatives such as benzyldimethyl ketal; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) ) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole Dimer, 2- (p-methoxy) 2,4,5-triarylimidazole dimers such as phenyl) -4,5-diphenylimidazole dimer; acridine derivatives such as 9-phenylacridine, 1,7-bis (9,9'-acridinyl) heptane N-phenylglycine, N-phenylglycine derivatives, coumarin compounds and the like. The substituents of the aryl groups of two 2,4,5-triarylimidazoles in the 2,4,5-triarylimidazole dimer may give the same and symmetrical compounds, but differently Asymmetric compounds may be provided. Moreover, you may combine a thioxanthone type compound and a tertiary amine compound like the combination of diethyl thioxanthone and dimethylaminobenzoic acid. These are used alone or in combination of two or more.

  Epoxy resins are sometimes used as curing agents. It is cross-linked by reacting with carboxylic acid of alkali-soluble resin to improve heat resistance and chemical resistance, but carboxylic acid and epoxy react at room temperature, so the storage stability is poor and alkaline In general, the development type solder resist generally takes a two-component form to be mixed before use. An inorganic filler may be used, and examples thereof include talc, barium sulfate, and silica.

  The method for forming the resist layer on the surface of the substrate may be any method, for example, screen printing method, roll coating method, spray method, dipping method, curtain coating method, bar coating method, air knife method, hot melt method, gravure. Examples thereof include a coating method, a brush coating method, and an offset printing method. In the case of a dry film resist, a laminating method is preferably used.

  In the exposure step, the resist layer is irradiated with actinic rays. Uses xenon lamps, high-pressure mercury lamps, low-pressure mercury lamps, ultra-high-pressure mercury lamps, reflection image exposure using UV fluorescent lamps as light sources, single-sided / double-sided contact exposure using photomasks, proximity method, projection method, laser scanning exposure, etc. be able to. When performing scanning exposure, a laser light source such as a UV laser, a He—Ne laser, a He—Cd laser, an argon laser, a krypton ion laser, a ruby laser, a YAG laser, a nitrogen laser, a dye laser, or an excimer laser is used as an emission wavelength. Accordingly, the exposure can be performed by scanning exposure using SHG wavelength conversion or scanning exposure using a liquid crystal shutter or a micromirror array shutter.

  In the development step, the resist layer in the unexposed area is developed with a developer. Unlike the thinning process, the resist layer in the unexposed area is completely removed. As a developing method, a method is generally used in which a developer corresponding to the resist layer to be used is used and a spray is sprayed toward the substrate surface. As the developer, an alkaline aqueous solution having a concentration lower than that of the thinning treatment solution (alkaline aqueous solution) used in the thinning treatment is used. As a developing solution (low-concentration alkaline aqueous solution), a sodium carbonate aqueous solution of 0.3 to 3% by mass is common.

  In the etching process, a method described in “Handbook of Printed Circuit Technology” (edited by Japan Printed Circuit Industry Association, published in 1987, published by Nikkan Kogyo Shimbun) can be used. The etching solution may be one that can dissolve and remove the metal layer, and at least the resist layer has resistance. In general, when copper is used for the metal layer, a ferric chloride aqueous solution, a cupric chloride aqueous solution, or the like can be used.

  The resist layer thinning step is a micellization process (thinning process) in which the photocrosslinkable resin component in the resist layer is micellized with an alkaline aqueous solution, and then the micelle removal process is performed to remove the micelle with an alkaline aqueous solution of pH 5-9. It is a process including. Furthermore, the resist layer surface that could not be removed and the remaining aqueous alkaline solution may be washed out by washing with water, and drying treatment may be performed to remove the washing water.

  Examples of the alkaline aqueous solution used as the thinning treatment liquid include alkali metal silicates such as lithium, sodium and potassium, alkali metal hydroxides, alkali metal phosphates, alkali metal carbonates, ammonium phosphates, Aqueous solutions of inorganic alkaline compounds such as ammonium carbonate, monoethanolamine, diethanolamine, triethanolamine, methylamine, dimethylamine, ethylamine, diethylamine, triethylamine, cyclohexylamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, An aqueous solution of an organic alkaline compound such as trimethyl-2-hydroxyethylammonium hydroxide (choline) can be used. The inorganic alkaline compound and organic alkaline compound can also be used as a mixture.

  The content of the alkaline compound can be 0.1% by mass or more and 50% by mass or less. In addition, sulfate and sulfite can be added to the aqueous alkaline solution in order to make the resist layer surface thinner evenly. Examples of the sulfate or sulfite include alkali metal sulfates or sulfites such as lithium, sodium or potassium, and alkaline earth metal sulfates or sulfites such as magnesium and calcium.

  Among these, as the aqueous alkali solution, among these, an inorganic alkaline compound selected from alkali metal carbonates, alkali metal phosphates, alkali metal hydroxides, alkali metal silicates, and organic alkaline compounds selected from TMAH and choline Among these, an alkaline aqueous solution containing at least any one of them and containing the inorganic alkaline compound and the organic alkaline compound in an amount of 5 to 25% by mass can be used suitably because the surface can be made more uniform. If it is less than 5% by mass, unevenness may easily occur in the process of thinning. Moreover, when it exceeds 25 mass%, precipitation of an inorganic alkaline compound will occur easily and it may be inferior to the temporal stability of a liquid, and workability | operativity. As for content of an alkaline compound, 7-17 mass% is more preferable, and 8-13 mass% is further more preferable. The pH of the alkaline aqueous solution is preferably 10 or more. Further, a surfactant, an antifoaming agent, a solvent and the like can be added as appropriate.

  The thinning process using an alkaline aqueous solution is performed by immersing (dip) a substrate on which a resist layer is formed in an alkaline aqueous solution in a dip tank. In treatment methods other than the dip treatment, bubbles are likely to be generated in the alkaline aqueous solution, and the generated bubbles may adhere to the surface of the resist layer during the thinning treatment, resulting in a non-uniform film thickness.

  In the resist pattern forming method using the resist tank thinning apparatus of the present invention, the thickness of the resist layer is determined by the thickness after the resist layer is formed and the amount of the resist layer thinned by the alkaline aqueous solution treatment. Further, the amount of thinning can be freely adjusted in the range of 0.01 to 500 μm.

  The resist layer thinning apparatus of the present invention includes a dip tank for thinning a resist layer with an alkaline aqueous solution, and a transport roll for transporting the substrate on which the resist layer is formed while being immersed in the alkaline aqueous solution. With a pair. And in order to suppress that a bubble adheres to the resist layer of a board | substrate, it is characterized by providing the bubble suppression board. A resist layer thinning apparatus according to the present invention will be described with reference to FIGS.

  The bubble guide plate is a part for suppressing bubbles generated in an alkaline aqueous solution from adhering to the resist layer during the thinning process. In the present invention, in the thinning process of the resist layer with an alkaline aqueous solution, It installs in a dip tank and suppresses that the bubble which generate | occur | produced adheres to a resist layer.

  7 and 8 are schematic cross-sectional views showing an example of the thinning device of the present invention. FIG. 7 is a schematic cross-sectional view seen from the CD direction, and FIG. 8 is a schematic cross-sectional view seen from the MD direction. These thinning apparatuses are thinning apparatuses that transport the substrate 8 on which a resist layer is formed in a state of being immersed in an aqueous alkaline solution 9 in a dip tank 10 by a pair of transporting rolls 12, and perform a thinning process on the resist layer. is there. The alkaline aqueous solution 9 is supplied from the alkaline aqueous solution storage tank 13 at the lower part of the apparatus to the dip tank 10 through the alkaline aqueous solution supply port 11 by the alkaline aqueous solution supply pump 14 and overflows. The overflowed alkaline aqueous solution 9 is recovered in the alkaline aqueous solution recovery tank 30 and stored in the alkaline aqueous solution storage tank 13 through the recovery pipe 21 through the recovery pipe discharge port 22, so that the dip tank 10, the alkaline aqueous solution storage tank 13, Cycle between.

  In the thin film forming apparatus shown in FIGS. 7 and 8, a bubble guide plate 16 is installed between the alkaline aqueous solution supply port 11 and the transport roll pair 12. By the bubble guide plate 16, the bubbles 15 generated in the alkaline aqueous solution circulation process in the thin film forming device are guided to the outer region in the width direction of the thin film forming device than the substrate 8 on which the resist layer being thinned is formed. It can prevent adhering to the board | substrate 8 with which the resist layer in it was formed.

  The position of the bubble guide plate 16 installed in the dip tank 10 is such that the alkaline aqueous solution supply port 11 is hidden behind the area of the bubble guide plate 16 when the dip tank 10 is viewed from above. Good. The height of the bubble guide plate 16 may be any height as long as it is between the alkaline aqueous solution supply port 11 and the transport roll pair 12 in the dip tank 10.

  About the magnitude | size of the bubble induction | guidance | derivation board 16, the length direction should just be the range beyond the diameter of the alkaline aqueous solution supply port 11 and below the length of the dip tank 10 with respect to the conveyance direction of a thin film forming apparatus. If the length direction is less than the diameter of the alkaline aqueous solution supply port 11 with respect to the transport direction of the thin film forming apparatus, the ability to induce bubbles may be insufficient. The width direction may be greater than or equal to the width of the substrate 8 on which the resist layer is formed and less than the width of the dip tank 10 with respect to the transport direction of the thinning device. If the width direction is less than the width of the substrate 8 on which the resist layer is formed with respect to the transport direction of the thin film forming apparatus, the ability to induce bubbles may be insufficient.

  As the material of the bubble guide plate 16, various materials resistant to an alkaline aqueous solution can be used. Specifically, polyethylene, polypropylene, hard polyvinyl chloride, acrylonitrile / butadiene / styrene (ABS) resin, synthetic resin such as polystyrene resin, fiber reinforced plastic such as glass fiber reinforced polypropylene and glass fiber reinforced epoxy resin, titanium, hastelloy A material such as a corrosion-resistant metal material such as (registered trademark) can be used. Of these, hard polyvinyl chloride is preferably used because it is easy to process.

  The shape of the bubble guide plate 16 can be a circle, an ellipse, a quadrangle such as a square or a rectangle, a polygon such as a pentagon or a hexagon, an arbitrary shape such as a straight line and an arc, etc. It is preferable that it is square or rectangular for ease of installation. In addition, by inclining the bubble guide plate 16 in a V shape in the width direction with respect to the transport direction of the thin film forming device, the bubbles can be guided more preferentially in the width direction. FIG. 8 shows a schematic cross-sectional view of the thin film forming apparatus when the bubble guide plate 16 is inclined in a V shape in the width direction with respect to the conveying direction of the thin film forming apparatus, as viewed from the front (MD direction).

  The present invention is characterized in that the bubble guide plate 16 has irregularities. 9a is a schematic enlarged view showing an example of the bubble guide plate 16 in the thin film forming apparatus shown in FIG. 7, and FIG. 9b is a schematic enlarged view showing an example of the bubble guide plate 16 in the thin film forming apparatus shown in FIG. FIG. The bubble guide plate 16 shown in FIGS. 9 a and 9 b has a recess 31. 10a is a schematic enlarged view showing an example of the bubble guide plate 16 in the thin film forming apparatus shown in FIG. 7, and FIG. 10b is a schematic enlarged view showing an example of the bubble guide plate 16 in the thin film forming apparatus shown in FIG. FIG. The bubble guide plate 16 shown in FIGS. 10 a and 10 b has a convex portion 32. When the bubble guide plate 16 having no irregularities is used, the bubble 15 is guided by the bubble guide plate 16 to a region outside in the thin film forming apparatus width direction from the substrate 8 on which the resist layer being thinned is formed. Even if the alkaline aqueous solution 9 has a low liquid temperature or a high concentration and a high viscosity, the extremely small bubbles 15 do not escape immediately into the air, and remain in the alkaline aqueous solution 9 as they are. There is a possibility that unevenness in processing may occur due to the flow of the alkaline aqueous solution 9 in the dip tank 10 toward the substrate 8. However, when the bubble guide plate 16 has the concave portion 31 and / or the convex portion 32, the extremely small bubble 15 is caught by the concave portion 31 and / or the convex portion 32 and stays there. Then, after the extremely small bubbles 15 gather and grow to a certain size, the bubbles 15 are guided to a region outside the substrate thinning apparatus width direction with respect to the substrate 8 on which the resist layer being thinned is formed. Therefore, the bubbles 15 quickly move into the air, and the occurrence of processing unevenness is suppressed. Note that the bubble guide plate 16 may have both the concave portion 31 and the convex portion 32.

  The cross-sectional shape of the unevenness may be any shape as long as it can retain the bubbles 15 such as a polygonal shape or a bowl shape. Concavities and convexities that are continuous in the conveying direction or the width direction, such as grooves and ridges, may be used. Further, the number of irregularities is not limited to the number shown in FIGS. 9 and 10 as long as the bubbles 15 can stay.

  The dip tank 10 and the alkaline aqueous solution recovery tank 30 in the resist layer thinning apparatus will be described. Regarding the circulation of the alkaline aqueous solution 9, the alkaline aqueous solution 9 is supplied into the dip tank 10 from the alkaline aqueous solution supply port 11, and the alkaline aqueous solution 9 overflowed from the dip tank 10 is recovered in the alkaline aqueous solution recovery tank 30. The alkaline aqueous solution 9 recovered in the alkaline aqueous solution recovery tank 30 is guided to the alkaline aqueous solution storage tank 13 through the recovery pipe 21, and again from the supply pump suction port 17 through the alkaline aqueous solution supply pump 14 through the alkaline aqueous solution supply port 11 into the dip tank 10. Sent to and circulated.

  The temperature of the aqueous alkaline solution 9 can be controlled by a heater for heating installed in the aqueous alkaline solution storage tank 13, a cooling pipe in which cooling water is circulated, and the like. The thermometer for temperature control is preferably installed not only in the alkaline aqueous solution storage tank 13 but also in the dip tank 10, so that the temperature of the alkaline aqueous solution 9 in the circulation path is kept more constant. There is no particular limitation on the size of the dip tank 10 as long as the alkaline aqueous solution is in contact with the resist layer when the substrate 8 on which the resist layer is formed by the transport roll pair 12 is transported and thinned. You can decide freely. Further, the shape and size of the alkaline aqueous solution recovery tank 30 may be freely determined as long as the overflow of the alkaline aqueous solution 9 can be recovered from the dip tank 10.

  The shape and material of the pair of transport rolls 12 are not particularly limited as long as they can transport the substrate on which the resist layer is formed. For example, polyolefin (polypropylene, etc.), polyvinyl chloride, fluororesin (Teflon (registered) Trademark) etc.). Further, the installation position and the number of the transport roll pairs 12 are not limited to the illustrated installation position and the number as long as the substrate 8 on which the resist layer is formed can be transported.

  The recovery pipe 21 is a pipe that guides the alkaline aqueous solution 9 that overflows from the dip tank 10 and is recovered in the alkaline aqueous solution recovery tank 30 to the alkaline aqueous solution storage tank 13. If the alkaline aqueous solution 9 overflowing from the dip tank 10 can be guided to the alkaline aqueous solution storage tank 13, the shape, thickness and length of the recovery tube 21 can be freely determined. Further, the number of the collection pipes 21 may be one or plural.

  Although the preferable diameter of the alkaline aqueous solution supply port 11 changes with the capacity | capacitance of the dip tank 10, it is 10-40 mm normally. Further, the position of the alkaline aqueous solution supply port 11 can be anywhere as long as it is the bottom of the dip tank 10. When the number of the alkaline aqueous solution supply ports 11 is one, it is preferable to be near the center of the bottom of the dip tank 10 from the circulation efficiency of the alkaline aqueous solution 9 in the dip tank 10. Moreover, since the movement of the bubble 15 in the alkaline aqueous solution 9 becomes complicated when the alkaline aqueous solution supply port 11 is installed on the side surface of the dip tank 10, it may be difficult to suppress the bubble with the bubble suppression device. In addition, when the alkaline aqueous solution supply port 11 is installed at the upper part of the dip tank 10, there is a possibility that a new bubble 15 is generated when the alkaline aqueous solution 9 is supplied.

  The material used for the resist layer thinning apparatus is not particularly limited. In the parts in contact with the alkaline aqueous solution, various materials resistant to the alkaline aqueous solution can be used.

  In the micellization process (thinning process) of the resist layer thinning process, the photocrosslinkable resin component in the resist layer is micellized with an aqueous alkaline solution, and then diluted with an alkaline compound in the micelle removal process. The micelles are removed by an aqueous solution containing 5 to 9 containing pH, and the resist layer becomes thinner. If the pH of the aqueous solution is less than 5, the resist layer components dissolved in the aqueous solution may aggregate to form insoluble sludge and adhere to the resist layer surface after thinning. On the other hand, when the pH of the aqueous solution exceeds 9, dissolution and diffusion of the resist layer is promoted, and processing unevenness tends to occur in the surface, which is not preferable. The pH of the aqueous solution can be adjusted using sulfuric acid, phosphoric acid, hydrochloric acid or the like. Moreover, as a method for supplying an aqueous solution having a pH of 5 to 9, a spray method is most preferable from the viewpoint of the dissolution / diffusion rate of the resist layer and the uniformity of liquid supply. The spray pressure is preferably 0.01 to 0.5 MPa, more preferably 0.02 to 0.3 MPa. Further, in order to efficiently create a liquid flow on the resist layer surface, spraying is preferably performed from a direction inclined with respect to a direction perpendicular to the resist layer surface.

  After the micelles are removed with an aqueous solution having a pH of 5 to 9, the resist layer surface that has not been removed and the remaining alkaline aqueous solution are washed away by a water washing treatment. As a method of washing with water, a spray method is preferable from the viewpoint of diffusion rate and liquid supply uniformity.

  In the drying process, either hot air drying or room temperature blowing drying can be used. However, a large amount of air is supplied using an air blower, and high-pressure air is blown from the air slit nozzle to the resist layer surface. The method of removing is preferable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this Example.

Example 1
Printed wiring board substrate 8 (insulating layer 1: glass substrate epoxy resin, metal layer 7: copper foil, area 510 mm × 340 mm, copper foil thickness 12 μm, substrate thickness 0.2 mm, MITSUBISHI GAS CHEMICAL COMPANY , INC.), Trade name: CCL-E170) using a laminator for dry film resist, dry film resist (manufactured by Hitachi Chemical Co., Ltd., trade name: RY3625, thickness 25 μm) Was subjected to thermocompression bonding to form a resist layer 3.

  Next, after peeling the carrier film of the dry film resist, using a 17% by mass sodium metasilicate aqueous solution (liquid temperature 20 ° C.) as the thinning treatment liquid (alkaline aqueous solution 9), the length in the transport direction is 500 mm, The dip tank 10 having a width of 750 mm and a depth of 200 mm has an alkaline aqueous solution supply port 11 having a diameter of 20 mm at the center of the bottom surface of the dip tank 10, and has a length of 500 mm, a width of 400 mm, and a thickness in the conveying direction immediately above the alkaline aqueous solution supply port 11. The thin film forming apparatus (FIG. 7) in which the 10 mm-long bubble guide plate 16 is installed supplies the alkaline aqueous solution 9 from the alkaline aqueous solution supply port 11 and circulates the alkaline aqueous solution 9 by overflowing the resist layer 3. Thinning treatment was performed. The resist layer 3 is placed on the lower surface of the substrate 8 and is transported by the transport roll pair 12 while being immersed in the alkaline aqueous solution 30 for 30 seconds. After the micelle removal treatment, the water washing treatment, and the drying treatment, the thickness of the thinned portion of the resist layer 3 is obtained. Was 12 μm. In addition, the bubble guide plate 16 has, as a recess 31, a total of three locations, a center line in the transport direction, a position 200 mm upstream from the center line and a position 200 mm downstream, a width 5 mm, a depth 2 mm, A groove having a triangular cross section is provided in the entire width direction.

  When 200 thin resist layers 3 were continuously formed and the surface of the thinned resist layer 3 was observed with an optical microscope, it was confirmed that there was no processing unevenness in all the substrates 8.

(Example 2)
A dip tank 10 having a length in the transport direction of 500 mm, a width of 750 mm, and a depth of 200 mm, and an alkaline aqueous solution supply port 11 having a diameter of 20 mm at the center of the bottom surface of the dip tank 10. A thinning apparatus (FIG. 9) in which a V-shaped bubble guide plate 16 having a length of 250 mm, a width of 400 mm, and a thickness of 10 mm and a height difference between the central portion and the end portion in the width direction of 30 mm was installed was used. Except for this, the resist layer 3 was thinned in the same manner as in Example 1. In addition, the bubble guide plate 16 has, as convex portions 32, a width of 5 mm, a height of 2.5 mm, and a cross-sectional shape at a total of four locations, 40 mm from both ends in the width direction and 40 mm from the center in the width direction. A rectangular ridge is provided in the entire conveying direction.

  When 200 thin resist layers 3 were continuously formed and the surface of the thinned resist layer 3 was observed with an optical microscope, it was confirmed that there was no processing unevenness in all the substrates 8.

(Comparative Example 1)
The resist layer 3 was thinned in the same manner as in Example 1 except that the bubble guide plate did not have the recess 31. When 200 thin resist layers 3 were continuously formed and the surface of the thin resist layer 3 was observed with an optical microscope, it was confirmed that there was no processing unevenness up to 150 resist layers. Between 151 and 200, four substrates 8 with processing unevenness were confirmed.

(Comparative Example 2)
The resist layer 3 was thinned in the same manner as in Example 2 except that the bubble guide plate did not have the convex portion 32. When 200 thin resist layers 3 were continuously formed and the surface of the thin resist layer 3 was observed with an optical microscope, it was confirmed that there was no processing unevenness up to 173 sheets. Between 174 and 200, two substrates 8 with processing unevenness were confirmed.

  The resist layer thinning apparatus of the present invention can be applied to the use of forming a resist pattern in the production of a circuit board on a printed wiring board or a lead frame, or in the production of a package substrate having a connection pad for flip chip connection.

DESCRIPTION OF SYMBOLS 1 Insulating layer 2 Conductor wiring 3 Resist layer 4 Photomask 5 Actinic ray 6 Connection pad 7 Metal layer 8 Substrate 9 Alkaline aqueous solution
DESCRIPTION OF SYMBOLS 10 Dip tank 11 Alkaline aqueous solution supply port 12 Conveying roll pair 13 Alkaline aqueous solution storage tank 14 Alkaline aqueous solution supply pump 15 Air bubbles 16 Bubble guide plate 17 Supply pump suction port 21 Recovery pipe 22 Recovery pipe discharge port 30 Alkaline aqueous solution recovery tank 31 Recess 32 Convex Part

Claims (1)

  A dipping bath for thinning the resist layer with an aqueous alkali solution, a pair of transport rolls for transporting the substrate on which the resist layer is formed while being immersed in the aqueous alkaline solution, and supplying the aqueous alkaline solution to the dipping bath In a resist layer thinning apparatus comprising an alkaline aqueous solution supply port, and a bubble guide plate provided between the alkaline aqueous solution supply port and a pair of transport rolls, the bubble guide plate has irregularities. Resist layer thinning device.