JP2018128482A - Film thinning device of resist layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film thinning device of a resist layer, used for thinning the resist layer in a substrate in which the resist layer is formed, capable of solving a problem that thinning process liquid is back flowing to an upstream side of a dip tank and thinning amount of the resist layer becomes non-uniform.SOLUTION: In a film thinning device of a resist layer having a film thinning process unit, the film thinning process unit has a dip tank including a thinning process liquid and prevents back flow of the thinning process liquid to the upstream side by a loading mechanism for applying a load to an upper side roll of an inlet roll pair of the dip tank.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resist layer thinning apparatus.

  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 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 improve the above points, various means have been proposed that can achieve high resolution while using a thick photosensitive resin. For example, in a method for producing a conductive pattern by a subtractive method, after forming a resist layer by pasting a dry film resist on a laminated substrate in which a metal layer is provided on one or both sides of an insulating layer, a thin film of the resist layer There is disclosed a method for forming a conductive pattern, which is characterized in that a process for forming a circuit pattern is performed, followed by a circuit pattern exposure process, a development process, and an etching process (for example, see 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).

  Patent Document 4 discloses a thinning device used in a resist layer thinning step. Specifically, the substrate on which the resist layer is formed is immersed (dip, dip) in a high-concentration alkaline aqueous solution (thinning treatment solution) to temporarily insolubilize the micelles of the resist layer components and dissolve and diffuse in the treatment solution. At least four treatment units: a thinning treatment unit that makes it difficult to remove, a micelle removal treatment unit that dissolves and removes micelles at once by spraying a micelle removal solution, a washing treatment unit that washes the surface with water, and a drying treatment unit that removes washing water. An apparatus for thinning a resist layer is disclosed.

  A part of the thinning apparatus disclosed in Patent Document 4 will be described with reference to the schematic cross-sectional view shown in FIG. In the thin film processing unit 11, the substrate 3 on which a resist layer is formed is input from the input port 7. After passing through the inlet roll pair 27 of the dip tank 2, the substrate 3 is transported while being immersed in the thinning solution 1 in the dip tank 2 by the transport roll pair 4, and the resist layer is thinned. . Thereafter, the substrate 3 is transferred to the micelle removal processing unit 12. In the micelle removal processing unit 12, the micelle removal liquid spray 22 is supplied from the micelle removal liquid nozzle 21 through the micelle removal liquid supply pipe 20 to the substrate 3 conveyed by the conveyance roll pair 4. The resist layer on the substrate 3 is micellized in the dip tank 2 inside the thin film processing unit 11 by the thin film processing solution 1 which is a highly concentrated alkaline aqueous solution. These micelles are insoluble in the thinning solution 1. Thereafter, the micelle is removed by the micelle removal liquid spray 22, whereby the resist layer is thinned.

  Further, in Patent Document 4, the pH of the micelle removal liquid 10 is increased by bringing a large amount of the thinning treatment liquid 1 taken out from the dip tank 2 in the thinning treatment unit 11 into the micelle removal treatment unit 12. In order to solve the problem that the micelle removal performance varies and the amount of thinning processing of the resist layer becomes non-uniform, the substrate 3 is formed inside the thinning processing unit 11 as shown in FIG. The resist layer thinning apparatus in which the liquid draining roll pair 8 which is a thinning treatment liquid take-out suppressing mechanism is installed while passing through the outlet roll pair 5 of the dip tank 2 and being transported to the micelle removal processing unit 12 is also provided. It is disclosed.

  The thinning treatment liquid take-out mechanism described in Patent Document 4 is a mechanism that suppresses the thinning treatment liquid 1 from flowing out on the downstream side of the dip tank 2. However, when the tip of the substrate 3 introduced from the introduction port 7 enters between the inlet roll pair 27 of the dip tank 2, the thinning treatment liquid 1 flows backward from between the rolls to the upstream side of the dip tank 2. It adheres to the part that is not in the dip tank 3. When the surface of the resist layer laminated on the substrate 3 has irregularities, this backflow phenomenon tends to occur more prominently because a gap is easily formed between the roll and the resist layer. As a result, since the amount of thinning varies between the resist layer to which the thinning treatment liquid 1 that has flowed back adheres and the resist layer that has not adhered, the amount of thinning of the resist amount on the substrate 3 may become uneven. there were.

  Thus, if the thickness of the resist layer after thinning becomes uneven and there is a thin part in the resist layer after thinning, the conductive pattern formation in the subtractive method may cause circuit disconnection. The solder resist pattern formation causes a decrease in weather resistance, both of which lead to a decrease in production yield.

International Publication No. 2009/096438 Pamphlet JP 2011-192692 A International Publication No. 2012/043201 Pamphlet Utility Model Registration No. 3186533

  An object of the present invention is to provide a resist layer thinning apparatus used for thinning a resist layer on a substrate on which a resist layer is formed. An object of the present invention is to provide a resist layer thinning device that can solve the problem of non-uniform formation.

  The present inventors have found that these problems can be solved by the following invention.

(1) In a resist layer thinning apparatus provided with a thinning processing unit, the thinning processing unit has a dip tank containing the thinning processing liquid, and the dip tank has a thinning processing liquid backflow prevention mechanism. An apparatus for thinning a resist layer.

(2) The resist layer thin film according to (1), wherein the dip tank has an inlet roll pair, and the thinning treatment liquid backflow prevention mechanism is a load mechanism that applies a load to the upper roll of the inlet roll pair of the dip tank. Device.

(3) The resist layer thinning apparatus according to (2), wherein the load mechanism is a load roll provided on the upper roll of the pair of inlet rolls in the dip tank.

(4) The resist layer thinning apparatus according to (2), wherein the load mechanism is a pair of inlet rolls in a dip tank in which the upper roll is heavier than the lower roll.

  According to the present invention, in the resist layer thinning apparatus used for thinning the resist layer on the substrate on which the resist layer is formed, the thinning treatment liquid flows backward to the upstream side of the dip tank, and the resist layer thin film It is possible to solve the problem that the amount of conversion becomes uneven.

It is a schematic sectional drawing which shows an example of the thin film forming apparatus of the resist layer of this invention. It is the expansion schematic which shows an example of the load mechanism in the thin film forming apparatus of the resist layer of this invention. It is a schematic sectional drawing which shows an example of the thin film forming apparatus of the resist layer of this invention. It is a schematic sectional drawing which shows an example of the thin film forming apparatus of the resist layer of this invention. It is a schematic sectional drawing which shows an example of the thin film forming apparatus of a resist layer. It is a schematic sectional drawing which shows an example of the thin film forming apparatus of a resist layer.

<Thinning process>
The thinning process of the resist layer is to supply a thinning treatment liquid to the resist layer formed on the substrate, to make micelles of the components in the resist layer with the thinning treatment liquid, and to insolubilize the micelles once. This is a step including a micelle removal process for dissolving and removing micelles on the surface of the resist layer at once by a thinning process that makes it difficult to dissolve and diffuse in the solution. Furthermore, it includes a micelle on the resist layer surface that could not be completely removed by the micelle removal treatment, a remaining thinning treatment solution and a washing treatment for washing the micelle removal solution with water, and a drying treatment for removing water used in the washing treatment. You can also.

<Thinning treatment>
The thinning treatment can be performed using paddle treatment, spray treatment, brushing, scraping or the like, but is preferably performed by dipping treatment. In the immersion treatment, the substrate on which the resist layer is formed is immersed (dip) in a thinning treatment solution. Treatment methods other than immersion treatment tend to generate bubbles in the thinning solution, and the generated bubbles adhere to the surface of the resist layer during the thinning treatment, and the thickness of the resist layer after thinning is not good. It may become uniform. When spraying or the like is used, the spray pressure must be as small as possible so that bubbles are not generated.

  In the present invention, the thickness of the resist layer after being thinned is determined by the thickness after the resist layer is formed and the amount by which the resist layer is thinned. Moreover, in this invention, the thinning amount of a resist layer can be freely adjusted in the range of 0.01-500 micrometers.

<Resist>
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 a high concentration alkaline aqueous solution (thinning treatment liquid) and is an alkaline aqueous solution with a concentration lower than that of the thinning treatment liquid. Any resist can be used as long as it can be developed with a developer. 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. The alkali-soluble resin is preferably obtained by polymerizing a monomer (polymerizable monomer) having an ethylenically unsaturated double bond (such as radical polymerization). These polymers soluble in an aqueous alkali solution may be used alone or in combination of two or more.

  Examples of the monomer having an ethylenically unsaturated double bond include styrene, vinyl toluene, α-methyl styrene, p-methyl styrene, p-ethyl styrene, p-methoxy styrene, p-ethoxy styrene, p- Styrene derivatives such as chlorostyrene and p-bromostyrene; acrylamide such as diacetone acrylamide; acrylonitrile; esters of vinyl alcohol such as vinyl-n-butyl ether; alkyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate Esters, (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 -Tetrafluo Such as propyl (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 ( (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, itacon An acid, crotonic acid, propiolic acid, etc. are mentioned.

  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 may 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'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone- Aromatic ketones such as 1; 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenyl Anthraquinone, 1 Quinones such as chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, 2,3-dimethylanthraquinone; benzoin methyl ether, benzoin ethyl Benzoin ether compounds such as ether and benzoin phenyl ether; benzoin compounds such as benzoin, methyl benzoin and ethyl benzoin; benzyl derivatives such as benzyl dimethyl 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-Diphenylimidazo Dimer, 2,4,5-triarylimidazole dimer such as 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer; 9-phenylacridine, 1,7-bis ( Acridine derivatives such as 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 may be 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 often 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.

  Any method may be used for forming the resist layer on the surface of the substrate. For example, a screen printing method, a roll coating method, a spray method, a dipping method, a curtain coating method, a bar coating method, an air knife method, a hot melt method, a gravure method. 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.

<Board>
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 large. 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). Scarlett, 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 in which the connection pad for connecting electronic components, such as a semiconductor chip, was formed on the insulating board | substrate. The connection pad is made of a metal such as copper. Further, conductor wiring may be formed on the circuit board. 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.

<Thinning device>
1, 3 and 4 are schematic views showing an example of the thinning apparatus of the present invention. The thin film forming apparatus of the present invention includes a thin film processing unit 11 that supplies a thin film processing solution 1 to a resist layer formed on a substrate 3 to make micelles of components in the resist layer. The thin film processing unit 11 has a dip tank 2 containing a thin film processing solution.

  In the thin film processing unit 11, the substrate 3 on which the resist layer is formed is input from the input port 7 to the thin film processing unit 11. After passing through the inlet roll pair 27 of the dip tank 2, the substrate 3 is transported by the transport roll pair 4 while being immersed in the thinning solution 1 in the dip tank 2, and the exit roll pair 5 of the dip tank 2. Pass through. By these processes, the components in the resist layer on the substrate 3 are micellized by the thinning treatment liquid 1, and the micelles are insolubilized in the thinning treatment liquid 1.

  The thinning treatment liquid 1 is sucked by a thinning treatment liquid supply pump (not shown) from a thinning treatment liquid suction port 14 in the thinning treatment liquid storage tank 13, and dip through the thinning treatment liquid supply pipe 15. It is supplied to the tank 2. The thinning treatment liquid 1 supplied to the dip tank 2 overflows and is collected in the thinning treatment liquid storage tank 13 through the thinning treatment liquid recovery pipe 16. In this way, the thinning treatment liquid 1 circulates between the dip tank 2 and the thinning treatment storage tank 13. From the thinning treatment liquid drain pipe 17, the excess thinning treatment liquid 1 is discharged.

  Examples of the alkaline compound used in the alkaline aqueous solution used as the thinning treatment liquid 1 include alkali metal silicates such as lithium, sodium and potassium, alkali metal hydroxides, alkali metal phosphates, alkali metal carbonates, Inorganic alkaline compounds such as ammonium phosphate and ammonium carbonate; monoethanolamine, diethanolamine, triethanolamine, methylamine, dimethylamine, ethylamine, diethylamine, triethylamine, cyclohexylamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium And organic alkaline compounds such as hydroxide and trimethyl-2-hydroxyethylammonium hydroxide (choline). These alkaline compounds may be used alone or as a mixture. As the water that is the medium of the thinning treatment liquid 1, tap water, industrial water, pure water, or the like can be used, but it is particularly preferable to use pure water.

  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 thinning solution 1 in order to make the resist layer surface more uniform. 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 alkaline compound of the thinning treatment solution 1, an inorganic alkaline compound selected from alkali metal carbonate, alkali metal phosphate, alkali metal hydroxide, alkali metal silicate; selected from TMAH and choline An organic alkaline compound can be preferably used. These alkaline compounds may be used alone or as a mixture. Moreover, since the alkaline aqueous solution whose content of an alkaline compound is 5-25 mass% can make the surface into a thin film more uniformly, it can be used conveniently. When the content of the alkaline compound is less than 5% by mass, the thickness of the resist layer after being thinned may be nonuniform. Moreover, when it exceeds 25 mass%, precipitation of an alkaline compound may 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 used as the thinning treatment solution 1 is preferably 10 or more. Further, a surfactant, an antifoaming agent, a solvent and the like can be added as appropriate.

  The temperature of the alkaline aqueous solution used as the thinning treatment solution 1 is preferably 15 to 35 ° C, more preferably 20 to 30 ° C. If the temperature is too low, the permeation rate of the alkaline compound into the resist layer may be slow, and it takes a long time to reduce the desired thickness. On the other hand, if the temperature is too high, dissolution and diffusion proceed simultaneously with the permeation of the alkaline compound into the resist layer, so that the thickness of the resist layer after being thinned may become non-uniform.

  In the micelle removal processing unit 12 provided after the thin film processing unit 11, the substrate 3 in which the resist layer is insolubilized in the thin film processing solution 1 in the thin film processing unit 11 is transported by the transport roll pair 4. The micelle removal liquid 10 is supplied to the substrate 3 being conveyed by the micelle removal liquid spray 22, and the micelles are dissolved and removed all at once.

  The micelle removal liquid 10 is sucked from the micelle removal liquid suction port 19 in the micelle removal liquid storage tank 18 by a micelle removal liquid supply pump (not shown) and removed through the micelle removal liquid supply pipe 20. Sprayed from the liquid nozzle 21 as a micelle removal liquid spray 22. The micelle removal liquid spray 22 flows down from the substrate 3 and is then collected in the micelle removal liquid storage tank 18. In this way, the micelle removal liquid 10 circulates in the micelle removal processing unit 12. From the micelle removal liquid drain pipe 23, the excess micelle removal liquid 10 is discharged.

  As the micelle removal liquid 10, water can be used, but it is preferable to use an aqueous solution having a pH of 5 to 10 containing an alkaline compound that is more dilute than the thinning treatment liquid 1. By the micelle removal liquid 10, the micelles of the components of the resist layer insolubilized with the thinning treatment liquid are redispersed and removed. As water used for the micelle removal liquid 10, tap water, industrial water, pure water, or the like can be used, but it is particularly preferable to use pure water. When the pH of the micelle removal solution 10 is less than 5, the components of the resist layer may aggregate to form insoluble sludge and adhere to the resist layer surface after thinning. On the other hand, when the pH of the micelle removal liquid 10 exceeds 10, the resist layer may be excessively dissolved and diffused, and the thickness of the resist layer thinned in the surface may be non-uniform. In addition, the micelle removal solution 10 can be adjusted in pH using sulfuric acid, phosphoric acid, hydrochloric acid, or the like.

The conditions (temperature, spray pressure, supply flow rate) of the micelle removal liquid spray 22 in the micelle removal process are appropriately adjusted according to the dissolution rate of the resist layer to be thinned. Specifically, the treatment temperature is preferably 10 to 50 ° C, more preferably 15 to 35 ° C. The spray pressure is preferably 0.01 to 0.5 MPa, more preferably 0.1 to 0.3 MPa. The supply flow rate of the micelle removal liquid 10 is preferably 0.030 to 1.0 L / min per 1 cm ² of the resist layer, more preferably 0.050 to 1.0 L / min, and further 0.10 to 1.0 L / min. preferable. When the supply flow rate is within this range, it is easy to remove the micelles of the resist layer components that have been insolubilized substantially uniformly in the plane without leaving insoluble components on the resist layer surface after thinning. If the supply flow rate per 1 cm ^{2 of the} resist layer is less than 0.030 L / min, insoluble resist layer components may be poorly dissolved. On the other hand, when the supply flow rate exceeds 1.0 L / min, parts such as a pump necessary for supply become enormous and a large-scale device may be required. Furthermore, when the supply amount exceeds 1.0 L / min, the effect of dissolving and diffusing the components of the resist layer may not change. The direction of spraying is preferably sprayed from a direction inclined with respect to the direction perpendicular to the resist layer surface in order to efficiently produce a liquid flow on the resist layer surface.

<Thinning treatment liquid backflow prevention mechanism>
In the thin film processing unit 11, when the tip of the substrate 3 input from the input port 7 enters between the inlet roll pair 27 of the dip tank 2, the thin film processing liquid 1 flows backward to the upstream side of the dip tank 2 from between the rolls. However, since the amount of thinning is changed between the resist layer to which the thinning treatment liquid 1 that has flowed back and adhered to the portion of the substrate 3 that has not entered the dip tank 3 and the resist layer that has not adhered thereto, the substrate 3 changes. In some cases, the resist film thickness in the film becomes non-uniform. Since the dip tank 2 has a thinning treatment liquid backflow prevention mechanism, backflow of the thinning treatment liquid 1 to the upstream side can be prevented.

  1, 3 and 4 are schematic views showing an example of a resist layer thinning apparatus according to the present invention. 1, 3 and 4, the dip tank 2 has an inlet roll pair 27, and the thinning treatment liquid backflow prevention mechanism loads the upper roll 30 of the inlet roll pair 27 of the dip tank 2. It is a load mechanism to apply. In the resist layer thinning apparatus of FIG. 1, the load mechanism is a load roll 29 provided on the upper roll 30 of the inlet roll pair 27 of the dip tank 2. FIG. 2 is an enlarged schematic view of the thinning treatment liquid backflow prevention mechanism in FIG. 1, and the load 3 is provided to the substrate 3 sandwiched between the inlet roll pair 27 of the dip tank 2. Is provided, the substrate 3 and the inlet roll pair 27 of the dip tank 2 are in close contact with each other, and the thinning solution can be prevented from flowing back to the upstream side. As a load mechanism, a mechanism for applying a load to the roll shaft 28 exposed at the width direction end of the upper roll 30 of the inlet roll pair 27 of the dip tank 2 is also useful. The load roll 29 is preferable in that the adhesiveness with the pair 27 is excellent.

  3 and 4, the load mechanism is the inlet roll pair 27 of the dip tank 2 having the upper roll 30 heavier than the lower roll 32. In FIG. 3, an elastic body having a higher density than the elastic body of the lower roll 32 is used as the surface elastic body of the upper roll 30. In FIG. 4, the weight of the roll shaft 31 in the upper roll is heavier than that of the roll shaft 28 in the lower roll.

  In addition to being able to transport the substrate 3, the transport roll pair 4 used in the thin film forming apparatus of the present invention is preferably in close contact with the resist layer surface. As the transport roll, a straight type having no irregularities on the surface is preferably used. Types of transport rolls include styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), silicone, ethylene-propylene-diene rubber (EPDM), rubber rolls such as fluorine; expanded polyvinyl alcohol (PVA), expanded polyvinyl chloride Sponge rolls such as (PVC); metal rolls; resin rolls such as polyolefin resins and fluororesins. Among them, it has excellent rubber elasticity (sealability, recoverability), low specific gravity, light weight, low to medium hardness, little impact from contact with the resist layer, and high concentration alkaline aqueous solution. An olefin thermoplastic elastomer or a vinyl chloride thermoplastic elastomer roll excellent in chemical resistance to a certain thinning treatment liquid 1 is preferable. An example of the olefin-based thermoplastic elastomer is THERMORUN (registered trademark), and an example of the PVC-based thermoplastic elastomer is sunplane (SUNPRENE, registered trademark). Moreover, the installation position and the number of transport rolls are not particularly limited to the installation position and the number shown in FIGS. 1, 2 and 4 as long as the substrate 3 can be transported.

  As the load roll 29, a roll having the same type, function, and physical properties as the transport roll pair 4 can be used. Further, in order to apply an appropriate load, the entire load roll 29 and the weight of the roll shaft of the load roll 29 can be appropriately changed. The lower roll 32 of the inlet roll pair 27 of the dip tank 2 can also use a roll having the same type, function, and physical properties as the transport roll pair 4. As the upper roll 30 of the inlet roll pair 27 of the dip tank 2, a roll having the same type, function, and physical properties as the transport roll pair 4 can be used except that the upper roll 30 is heavier than the lower roll 32.

  A roll having the same type, function, and physical properties as the transport roll pair 4 is also preferably used for the outlet roll pair 5 of the dip tank, the outlet roll pair 6 of the thin film processing unit, and the inlet roll pair 9 of the micelle removal processing unit. In particular, the pair of outlet rolls 5 in the dip tank is used for maintaining the liquid level of the thinning treatment liquid 1 in the dip tank 2 and for cutting off the liquid film of the thinning treatment liquid 1 coated on the resist layer surface. . The outlet roll pair 6 of the thin film processing unit is used to suppress the introduction of the thin film processing liquid 1 into the micelle removal processing unit 12 and the reverse flow of the micelle removal liquid 10 into the thin film processing unit 11. The inlet roll pair 9 of the micelle removal processing unit is mainly used for damming the micelle removal liquid 10 flowing back into the thinning processing unit.

  Although not shown in FIGS. 1, 2 and 4, it is shown in FIG. 6 between the outlet roll pair 5 of the dip tank and the outlet roll pair 6 of the thin film processing unit 11 inside the thin film processing unit 11. The liquid draining roll pair 8 may be installed. The liquid film of the thinning treatment liquid 1 is scraped off by the liquid cutting roll pair 8 and the thickness of the liquid film is made uniform. The substrate 3 on which the liquid film of the thinning processing liquid 1 is uniformly arranged passes through the outlet roll pair 6 of the thinning processing unit and is then transported to the micelle removal processing unit 12. The pair of liquid draining rolls 8 has the effect even if it is a pair, but a larger effect can be obtained by continuously draining liquid with a plurality of roll pairs. It is important that the liquid draining roll pair 8 is in close contact with the resist layer surface. Therefore, as the liquid draining roll, a straight type having no irregularities on the surface is preferably used. As a kind of liquid draining roll, the same kind as the above-mentioned conveyance roll is suitably used.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to these examples.

Example 1
Dry film resist on glass substrate epoxy resin substrate (area 510 mm x 340 mm, copper foil thickness 12 μm, substrate thickness 0.2 mm, manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC., Trade name: CCL-E170) A dry film resist (manufactured by Hitachi Chemical Co., Ltd., trade name: RY3625, thickness 25 μm) was thermocompression bonded using a laminator for use to form a resist layer.

  Next, after peeling the carrier film of the dry film resist, the thinning processing unit 11 has a dip tank 2 containing the thinning processing liquid, and the dip tank 2 has a backflow prevention mechanism for the thinning processing liquid. The dip tank 2 has an inlet roll pair 27, the thinning treatment liquid backflow prevention mechanism is a load mechanism for applying a load to the upper roll of the inlet roll pair 27 of the dip tank, and the load mechanism is a load roll 29. The resist layer was thinned using a layer thinning apparatus (FIG. 1).

  In this resist layer thinning apparatus, a load roll 29 is provided in the thinning processing unit 11 when the tip of the substrate 3 introduced from the inlet 7 enters between the inlet roll pair 27 of the dip tank 2. As a result, a load is applied to the substrate 3 sandwiched between the inlet roll pair 27 of the dip tank 2. And the board | substrate 3 and the inlet roll pair 27 of the dip tank 2 closely_contact | adhered, and it was able to prevent that the thinning process liquid 1 flows back upstream.

  Using a 10% by mass sodium carbonate aqueous solution (liquid temperature: 25 ° C.) as the thinning treatment solution 1 (alkaline aqueous solution), the thinning treatment was performed so that the immersion treatment time in the dip tank 2 was 30 seconds. Thereafter, in the micelle removal processing unit 12, the insolubilized micelles were removed, and the resist layer was thinned. After the micelle removal treatment, a water washing treatment and a drying treatment were performed. Thereafter, when the thickness of the thinned portion of the resist layer was measured at 10 points, the maximum value was 13.3 μm, the minimum value was 10.9 μm, and the average thickness was 12.1 μm. Further, when the surface of the thinned resist layer was observed with an optical microscope, it was confirmed to be a smooth surface.

(Example 2)
The thinning treatment liquid backflow prevention mechanism is the inlet roll pair 27 of the dip tank 2 having the upper roll 30 heavier than the lower roll 32, and the elastic body of the upper roll 30 is more elastic than the elastic body of the downstream roll 32. The resist layer was thinned in the same manner as in Example 1 except that the resist layer thinning apparatus (FIG. 3) using an elastic body having a high density was used. Even in this resist layer thinning apparatus, the thinning treatment liquid 1 could be prevented from flowing backward to the upstream side of the inlet roll pair 27 of the dip tank 2. When the thickness of the thinned portion of the resist layer was measured at 10 points, the maximum value was 13.2 μm, the minimum value was 11.0 μm, and the average thickness was 12.2 μm. Further, when the surface of the thinned resist layer was observed with an optical microscope, it was confirmed to be a smooth surface.

(Example 3)
The thinning treatment liquid backflow prevention mechanism is the inlet roll pair 27 of the dip tank 2 having the upper roll 30 heavier than the lower roll 32, and the roll shaft 31 in the upper roll is heavier than the roll shaft 28 of the downstream roll. The resist layer was thinned in the same manner as in Example 1 except that the resist layer thinning apparatus (FIG. 4) was used. Even in this resist layer thinning apparatus, the thinning treatment liquid 1 could be prevented from flowing backward to the upstream side of the inlet roll pair 27 of the dip tank 2. When the thickness of the thinned portion of the resist layer was measured at 10 points, the maximum value was 13.1 μm, the minimum value was 11.1 μm, and the average thickness was 12.2 μm. Further, when the surface of the thinned resist layer was observed with an optical microscope, it was confirmed to be a smooth surface.

(Comparative Example 1)
The resist layer was thinned in the same manner as in Example 1 except that a resist layer thinning apparatus (FIG. 5) without a thinning treatment liquid backflow prevention mechanism was used. In this resist layer thinning apparatus, the thinning treatment liquid 1 flowed upstream to the upstream side of the inlet roll pair 27 of the dip tank 2. When the thickness of the thinned portion of the resist layer was measured at 10 points, the maximum value was 13.5 μm, the minimum value was 10.6 μm, and the average thickness was 11.8 μm. Further, when the surface of the thinned resist layer was observed with an optical microscope, the thickness was not uniform.

  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 Thin film processing liquid 2 Dip tank 3 Substrate 4 Conveying roll pair 5 Dip tank outlet roll pair 6 Thin film processing unit outlet roll pair 7 Input port 8 Liquid draining roll pair 9 Micelle removal processing unit inlet roll pair 10 Micelle removal Liquid 11 Thinning treatment unit 12 Micelle removal processing unit 13 Thinning treatment liquid storage tank 14 Thinning treatment liquid inlet 15 Thinning treatment liquid supply pipe 16 Thinning treatment liquid recovery pipe 17 Thinning treatment liquid drain pipe 18 Micellar removal liquid Storage tank 19 Micelle removal liquid inlet 20 Micelle removal liquid supply pipe 21 Micelle removal liquid nozzle 22 Micelle removal liquid spray 23 Micelle removal liquid drain pipe 24 Thinning liquid supply pipe for liquid draining roll pair 25 Nozzle for liquid draining roll pair 26 Liquid dipping roll pair roll immersion tank 27 Dip tank inlet roll pair 28 Roll shaft (light)
29 Load roll 30 Upper roll of inlet roll pair of dip tank 31 Roll shaft (heavy)
32 Dip tank inlet roll pair lower roll

Claims (4)

  In the resist layer thinning apparatus provided with the thinning processing unit, the thinning processing unit has a dip tank containing the thinning processing liquid, and the dip tank has a backflow prevention mechanism for the thinning processing liquid. Resist layer thinning device.   2. The resist layer thinning apparatus according to claim 1, wherein the dip tank has an inlet roll pair, and the thinning treatment liquid backflow prevention mechanism is a load mechanism that applies a load to the upper roll of the inlet roll pair of the dip tank.   3. The resist layer thinning apparatus according to claim 2, wherein the load mechanism is a load roll provided on an upper roll of an inlet roll pair of a dip tank.   3. The resist layer thinning apparatus according to claim 2, wherein the load mechanism is a pair of inlet rolls in a dip tank in which the upper roll is heavier than the lower roll.