CN113614204A - Etching solution for liquid crystal polymer and etching method for liquid crystal polymer - Google Patents
Etching solution for liquid crystal polymer and etching method for liquid crystal polymer Download PDFInfo
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- CN113614204A CN113614204A CN202080022278.2A CN202080022278A CN113614204A CN 113614204 A CN113614204 A CN 113614204A CN 202080022278 A CN202080022278 A CN 202080022278A CN 113614204 A CN113614204 A CN 113614204A
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K13/00—Etching, surface-brightening or pickling compositions
- C09K13/02—Etching, surface-brightening or pickling compositions containing an alkali metal hydroxide
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
- C08J7/02—Chemical treatment or coating of shaped articles made of macromolecular substances with solvents, e.g. swelling agents
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
- H01L21/308—Chemical or electrical treatment, e.g. electrolytic etching using masks
Abstract
The invention provides an etching liquid for a liquid crystal polymer and an etching method for the liquid crystal polymer, wherein the shape of the liquid crystal polymer after etching is close to the designed shape, and the liquid crystal polymer can be etched with high in-plane uniformity. The etching liquid for liquid crystal polymer and the etching method of liquid crystal polymer using the same are characterized in that the etching liquid contains 5-45 mass% of alkali metal hydroxide as a component 1 and 5-80 mass% of alkanolamine compound with molecular weight of more than 70 as a component 2, preferably further contains 1-60 mass% of a component 3, and the component 3 contains at least 1 selected from alcohol compound and carboxylic acid compound.
Description
Technical Field
The present invention relates to a low dielectric constant polymer suitable for use in flexible circuit applications, and specifically to an etching liquid for Liquid Crystal Polymer (LCP) and a method of etching liquid crystal polymer.
Background
In recent years, with miniaturization, high performance, high precision, high frequency of signals, and the like of electronic devices, there has been a demand for formation of fine wiring on circuit boards, reduction of thermal expansion coefficient of insulating materials and/or substrate materials, reduction of dielectric constant, reduction of dielectric loss tangent, and the like. Among them, attention is being paid to a liquid crystal polymer film having a small heat resistance, water absorption and/or dielectric constant and excellent dimensional accuracy, which are required for solder bonding.
However, since a liquid crystal polymer represented by a liquid crystal polyester has a rigid liquid crystal structure as a molecular structure, has high chemical resistance, and does not have water absorption and/or hydrophilicity, a polyethylene terephthalate, which is a general-purpose polyester resin, has an excessively low etching rate in etching with an aqueous caustic alkali solution, which has been conventionally used in etching treatments such as surface processing, and thus cannot be subjected to practically satisfactory etching. Therefore, recently, an etching method has been proposed in which an etching solution mainly composed of an inorganic alkali aqueous solution and aminoalcohol, which has been developed as an etching solution for polyimide, is used as an etching solution for liquid crystal polymer.
For example, the following technique is disclosed in Japanese patent application laid-open No. 2004-504439 (patent document 1): a liquid crystal polymer is etched at 50 to 120 ℃ using an aqueous solution containing 35 to 55 wt% of a high-concentration inorganic alkali salt and 10 to 35 wt% of a water-soluble solubilizer (ethanolamine). Further, japanese patent application laid-open No. 2006-: the etching solution for liquid crystal polymer is an aqueous solution which is composed of 30 wt% or more and less than 35 wt% of inorganic alkali compound such as alkali metal hydroxide, 45-50 wt% of aliphatic amino alcohol having at least 1 amino group and hydroxyl group in the molecule and water, and has a total alkali component concentration of 75-80 wt%, and the liquid crystal polymer is etched at a liquid temperature of 60-90 ℃. However, when they are processed in large sizes or in roll-to-roll in industrial applications, the uniform handling performance in the surface is not sufficient, and they are not sufficient for industrial applications.
Further, as a technique capable of performing etching with a clean and uniform etching shape, a technique of irradiating laser light and ultraviolet light before and/or during etching is disclosed in japanese patent laid-open nos. 2002-20513 (patent document 3) and 2001-172416 (patent document 4), and a technique of irradiating at least 1 selected from ultraviolet light, microwave, laser light, and infrared light at the time of wet etching is disclosed in japanese patent laid-open nos. 2002-184816 (patent document 5). However, when they are processed in a large size, the uniform in-plane processing performance is not sufficient, and they are not sufficient for industrial use. As a technique for providing an etching solution which can perform etching in a short time and has a clean, uniform and uniform etching shape, a technique of adding an electron donor to the etching solution is disclosed in japanese patent laid-open No. 2001-310959 (patent document 6), but this technique is not sufficient.
In addition, compared to the etching solution-based processing that can perform a large amount of processing at a time with a simple apparatus and has high productivity, the laser etching-based method has the following problems: since the device is large in scale and the productivity is low because the liquid crystal polymer is thermoplastic, the resin is deformed by the heat of the laser beam, and the patterns such as the wiring and the via hole formed thereon are deformed, and the patterning conforming to the design cannot be performed. Therefore, an etching method without using a laser is sought.
In addition, a circuit board using a liquid crystal polymer as an insulating layer is generally formed by bonding a metal layer such as a copper foil to the insulating layer by thermocompression bonding or the like, and then removing an unnecessary metal layer by etching.
When the liquid crystal polymer bonded to the metal layer is etched and washed with water after etching in accordance with the methods disclosed in patent documents 1 and 2, a part of the bonding surface between the metal layer and the liquid crystal polymer may be peeled off. Therefore, an etching method is required in which peeling of the bonding surface between the metal layer and the liquid crystal polymer does not occur.
Documents of the prior art
Patent document
Patent document 1: japanese Kokai publication Hei-2004-504439
Patent document 2: japanese patent laid-open No. 2006 and 282791
Patent document 3: japanese laid-open patent publication No. 2002-20513
Patent document 4: japanese patent laid-open publication No. 2001-172416
Patent document 5: japanese laid-open patent publication No. 2002-184816
Patent document 6: japanese patent laid-open publication No. 2001-310959
Disclosure of Invention
Problems to be solved by the invention
The invention provides a novel etching solution suitable for liquid crystal polymer, an etching method using the etching solution, and the like.
Another object of the present invention is to provide an etching solution for a liquid crystal polymer and an etching method for a liquid crystal polymer, which can etch a liquid crystal polymer in a shape close to a design shape and with high in-plane uniformity after etching.
Still another object of the present invention is to provide a method for etching a liquid crystal polymer, which can rapidly etch the liquid crystal polymer after etching, and has high productivity.
It is still another object of the present invention to provide a method for etching a liquid crystal polymer, which does not cause separation of a bonding surface between a metal layer and the liquid crystal polymer when the liquid crystal polymer bonded to the metal layer is etched.
Means for solving the problems
The present inventors have conducted extensive studies to solve the above problems, and as a result, have found that a novel etching solution is obtained by combining specific components (and combining the components at a predetermined ratio), and that such an etching solution is suitable for etching of a liquid crystal polymer, and in particular, can efficiently perform etching of a liquid crystal polymer (for example, can make the shape of a liquid crystal polymer after etching close to a design shape, can perform etching with high in-plane uniformity, and the like), and have further conducted extensive studies, thereby completing the present invention.
That is, the present invention relates to the following inventions and the like.
<1>
An etching solution for liquid crystal polymers, characterized in that the etching solution contains 5-45 mass% of alkali metal hydroxide as a component 1 and 5-80 mass% of alkanolamine compound with molecular weight of 70 or more as a component 2.
<2>
The etching solution for liquid crystal polymers according to <1>, characterized in that the etching solution for liquid crystal polymers further contains 1 to 60 mass% of a 3 rd component, and the 3 rd component contains at least 1 selected from an alcohol compound and a carboxylic acid compound.
<3>
The etchant for liquid crystal polymers according to <2>, wherein the 3 rd component contains at least 1 selected from the group consisting of a polyol compound, a polycarboxylic acid compound and a hydroxy acid compound.
<4>
The etching solution according to <2> or <3>, wherein the 3 rd component contains a polyol compound.
<5>
The etching solution according to <3> or <4>, wherein the molecular weight of the polyol compound is 80 or more and 200 or less.
<6>
The etching solution according to any one of <3> to <5>, wherein the polyol compound has 3 or more hydroxyl groups.
<7>
The etching solution according to any one of <3> to <6>, wherein the polyol compound contains glycerol.
<8>
The etching solution according to any one of <2> to <7>, wherein the 3 rd component contains a polycarboxylic acid compound.
<9>
The etching solution according to any one of <2> to <8>, wherein the 3 rd component contains a hydroxy acid compound.
<10>
A method for etching a liquid crystal polymer, comprising an etching step of etching the liquid crystal polymer using the etching solution according to any one of <1> to <9 >.
<11>
The method for etching a liquid crystal polymer according to <10>, wherein the method further comprises a pretreatment step of bringing a pretreatment liquid containing 50 to 100 mass% of an alkanolamine compound into contact with the liquid crystal polymer before the etching step.
<12>
The method for etching a liquid crystal polymer according to <11>, wherein the temperature of the pretreatment liquid is 50 ℃ or more.
<13>
The method for etching a liquid crystal polymer according to any one of <10> to <12>, wherein the etching method further comprises a water washing step using a water washing liquid (water washing water or the like) after the etching step.
<14>
The method for etching a liquid crystal polymer according to item <13>, wherein the washing step includes a first washing step using a first washing liquid and a second washing step using a second washing liquid in this order, and the temperature of the etching liquid-the temperature of the first washing liquid is less than 25 ℃, and the temperature of the first washing liquid-the temperature of the second washing liquid is less than 25 ℃.
<15>
The method for etching a liquid crystal polymer according to <13> or <14>, wherein a water-washing liquid (water-washing water or the like) [ a water-washing liquid (water-washing water or the like) used in the water-washing step (for example, the first water-washing step and/or the second water-washing step) ] is supplemented to the etching liquid.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, a novel etching solution suitable for a liquid crystal polymer, an etching method using the etching solution, and the like can be provided.
In another aspect of the present invention, an etching solution for a liquid crystal polymer and a method for etching a liquid crystal polymer can be provided, in which the shape of a liquid crystal polymer after etching is close to a design shape and etching can be performed with high in-plane uniformity.
In another aspect of the present invention, there is provided a method for etching a liquid crystal polymer, which can form a liquid crystal polymer after etching into a shape conforming to a design and can rapidly etch the liquid crystal polymer with high productivity.
In another aspect of the present invention, there is provided a method for etching a liquid crystal polymer, wherein when the liquid crystal polymer bonded to the metal layer is etched, the bonding surface between the metal layer and the liquid crystal polymer is not peeled.
Detailed Description
Hereinafter, embodiments for carrying out the present invention will be described. In the present specification, the "liquid crystal polymer etching solution" may be simply referred to as "etching solution", and the "liquid crystal polymer etching method" may be simply referred to as "etching method".
The etching solution is used for removing liquid crystal polymer. The etching method of the present invention is characterized by comprising an etching step of etching a liquid crystal polymer using the etching solution of the present invention.
< etching solution >
The etching solution of the present invention is an etching solution for liquid crystal polymers (an etching solution for liquid crystal polymers, a liquid for etching liquid crystal polymers).
The etching solution of the present invention generally contains an alkali metal hydroxide (particularly, 5 to 45 mass% of an alkali metal hydroxide) as the component 1. When the content of the alkali metal hydroxide (the ratio to the entire etching solution, hereinafter, the same in the same expression) is 5% by mass or more, the solubility of the liquid crystal polymer is excellent, and when the content of the alkali metal hydroxide is 45% by mass or less, the precipitation of the alkali metal hydroxide is less likely to occur, so that the etching becomes uniform, and the stability of the etching solution with time is excellent. The content of the alkali metal hydroxide is more preferably 10 to 30% by mass.
As the above-mentioned alkali metal hydroxide, at least 1 compound selected from potassium hydroxide, sodium hydroxide and lithium hydroxide is suitably used. As the alkali metal hydroxide, 1 kind of them may be used alone, or 2 or more kinds may be used in combination.
The etching solution of the present invention generally contains an alkanolamine compound (generally, an ethanolamine compound, particularly, 5 to 80 mass% of an ethanolamine compound having a molecular weight of 70 or more) as the component 2. The etching solution contains an alkanolamine compound or the like, and the alkanolamine compound or the like can permeate into the liquid crystal polymer to dissolve and swell the liquid crystal polymer in this order, thereby uniformly dissolving the liquid crystal polymer. When the content of the alkanolamine compound (for example, ethanolamine compound) is 5% by mass or more, the liquid crystal polymer is excellent in swellability, and when the content of the alkanolamine compound is 80% by mass or less, the compatibility with water becomes high, phase separation is difficult to occur, and the stability with time is excellent. The content of the alkanolamine compound (e.g., ethanolamine compound) is more preferably 25 to 75 mass%.
In the etching solution of the present invention, when an alkanolamine compound having a molecular weight of less than 70 (for example, 2-aminoethanol or the like) is used, it is preferable to use an alkanolamine compound having a molecular weight of 70 or more in combination. In the case where the etching solution does not contain an alkanolamine compound having a molecular weight of less than 70, the etching uniformity is further improved.
The alkanolamine compound (e.g., ethanolamine compound) may be any of primary amine, secondary amine, tertiary amine, and the like, and 1 species may be used alone or 2 or more species may be used in combination. As an example of a typical alkanolamine compound (alkanolamine compound having a molecular weight of 70 or more), there can be mentioned: 2- (2-aminoethylamino) ethanol as a mixture of primary and secondary amines (i.e., a compound having a primary amino group and a secondary amino group in one molecule); 2- (methylamino) ethanol or 2- (ethylamino) ethanol as a secondary amine; examples of the tertiary amine include 2, 2' -methyliminodiethanol and 2- (dimethylamino) ethanol. Among these, 2- (methylamino) ethanol and 2- (2-aminoethylamino) ethanol are more preferable.
The etching solution of the present invention preferably contains at least 1 type of component 3 (third component) selected from an alcohol compound and a carboxylic acid compound.
The content of the 3 rd component (the total content thereof in the case of 2 or more kinds in combination) also depends on the components constituting the 3 rd component, but in the etching solution, for example: 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, 1.5% by mass or more, 2% by mass or more, 3% by mass or more, 5% by mass or more, 8% by mass or more, 10% by mass or more, and the like.
Further, although the content of the 3 rd component also depends on the component constituting the 3 rd component, in the etching solution, for example: 80% by mass or less, 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, and the like.
In particular, the etching solution of the present invention preferably contains the 3 rd component in an amount of 1 to 60% by mass. The third component may contain a polyol compound, a polycarboxylic acid compound and/or a hydroxy acid compound. The etching solution of the present invention can dissolve the liquid crystal polymer more uniformly by containing the component 3 (for example, a polyol compound, a polycarboxylic acid compound, and/or a hydroxy acid compound).
The mechanism of this effect is not beyond the range estimated, but the third component is considered to have an effect of rapidly removing the dissolved liquid crystal polymer from the dissolution surface to advance the dissolution of the liquid crystal polymer, thereby eliminating the unevenness of etching caused by the influence of the dissolved liquid crystal polymer. In addition, as another effect, when the liquid crystal polymer is continuously subjected to the etching treatment, carbon dioxide gas in the air is absorbed, and insoluble precipitates are generated in the liquid crystal polymer etching solution. The precipitates adhere to the liquid crystal polymer during the etching treatment, and thus a problem arises that the uniform treatment is hindered. However, it is considered that the third component has an effect of dissolving the insoluble precipitate without adversely affecting the etching performance, and thus, a more uniform etching treatment can be performed, and the workability is improved. If the content of the third component is small (for example, less than 1 mass%), the uniformity improving effect may not be improved with respect to the etching solution containing no third component, and if the content of the third component is large (for example, more than 60 mass%), the dissolution performance of the etching solution may be insufficient. The content of the third component is more preferably 10 to 40% by mass.
[ alcohol Compound ]
The alcohol compound [ the alcohol compound other than the alkanolamine compound (ethanolamine compound) ] includes a monohydric alcohol compound [ for example, an alkanol (for example, ethanol, propanol, butanol, pentanol, hexanol, etc.), a non-aromatic monohydric alcohol compound (aliphatic monohydric alcohol) such as an alicyclic monohydric alcohol (for example, cyclohexanol), etc. ], a polyhydric alcohol compound, and the like.
The alcohol compound may be used alone in 1 kind, or 2 or more kinds may be used in combination.
The alcohol compound may preferably comprise a polyol compound.
The alcohol compound may be an aromatic alcohol compound [ an aromatic alcohol compound (e.g., benzyl alcohol, phenoxyethanol, etc.) described later ], a non-aromatic alcohol compound (a non-aromatic monohydric alcohol compound, a non-aromatic polyhydric alcohol compound), or both of them.
The non-aromatic alcohol compound may be either a saturated compound or an unsaturated compound.
Typically, the alcohol compound contains at least a non-aromatic alcohol compound (particularly a non-aromatic polyol compound) in many cases. On the other hand, as described later, the aromatic alcohol compound may be appropriately combined with the 3 rd component (and with the 1 st and 2 nd components).
The polyhydric alcohol compound used in the etching solution of the present invention has a preferable molecular weight range, preferably 80 to 200. Further, as the polyol compound, a compound having 3 or more hydroxyl groups is preferable.
Further, as a preferable polyol compound, a compound in which hydroxyl groups are relatively densely present is exemplified. In such polyol compounds, the average molecular weight to 1 hydroxyl group may be, for example: 100 or less, 80 or less, 60 or less, 50 or less, 40 or less, 35 or less, and the like.
The polyol compound may be any of an aliphatic polyol compound and an aromatic polyol compound, but it is particularly preferable to use at least an aliphatic polyol compound (e.g., an alkane polyol). The polyol compound may be a sugar and/or a sugar alcohol.
Specific examples include: polyhydric alcohol having 3 or more hydroxyl groups [ e.g., alkanetriol (e.g., C such as glycerin, trimethylolpropane, etc.)3-10Alkanetriol), alkanetetraol (e.g. erythritol, pentaerythritol, etc. C)4-12Alkanetetraols), alkane polyols having 5 or more hydroxyl groups (e.g., sorbitol, xylitol, heptanol (Volemitol), etc.), polymers of polyols having 3 or more hydroxyl groups (e.g., diglycerol, dipentaerythritol), etc]And a glycol [ e.g., a poly (alkylene glycol) [ e.g., a poly (C) such as diethylene glycol or dipropylene glycol ]2-6Alkanediol]And alkanediol (e.g. C. such as ethylene glycol, propylene glycol, butylene glycol, etc.)2-10Alkanediol), etc]. Among them, glycerin, pentaerythritol, sorbitol, xylitol and the like are preferable, and glycerin is particularly preferable. Further, as the polyol compound, 1 kind may be used alone, orMore than 2 kinds are used in combination.
When the liquid crystal polymer etching solution contains a polyol compound, the liquid crystal polymer etching solution of the present invention may preferably contain at least 1 or more of the polyol compound in the above-mentioned proportion (for example, 1 to 60 mass%). The content of the polyol compound is more preferably 10 to 40% by mass.
[ carboxylic acid Compound ]
As the carboxylic acid compound (sometimes simply referred to as "carboxylic acid"), carboxylic acids, carboxylic acid derivatives (for example, carboxylate salts), and the like are included. The carboxylic acid compound (carboxylic acid, carboxylate salt, etc.) may be a hydrate or the like.
Examples of the carboxylic acid include: monocarboxylic acids (monocarboxylic acids), polycarboxylic acids (polycarboxylic acids described later, etc.), hydroxy acids (hydroxy acids described later, etc.), and the like.
Examples of the monocarboxylic acid include fatty acids [ for example: alkanoic acids (e.g. C) such as formic acid, acetic acid, propionic acid1-10Alkanoic acid)]And the like.
The carboxylic acid may be an amino acid (aminocarboxylic acid).
The salt is not particularly limited, and examples thereof include metal salts [ e.g., alkali metal salts (e.g., lithium salt, sodium salt, potassium salt, etc.), alkaline earth metal salts (e.g., magnesium salt, calcium salt, etc.), zinc salt, etc. ], amine salts, ammonium salts, and the like.
The carboxylic acid compounds can be used alone in 1, can also be used in combination with more than 2.
Preferred carboxylic acid compounds include polycarboxylic acid compounds and hydroxy acid compounds. Accordingly, the carboxylic acid compound may comprise at least 1 selected from the group consisting of a polycarboxylic acid compound and a hydroxy acid compound.
(polycarboxylic acid Compound)
As described above, the polycarboxylic acid (polycarboxylic acid compound) used in the etching solution of the present invention also includes a derivative (for example, a salt or the like) and/or a hydrate of the polycarboxylic acid. The polycarboxylic acid may be any of aliphatic polycarboxylic acids and aromatic polycarboxylic acids, and typically, aliphatic polycarboxylic acids may be suitably used. Such an aliphatic polycarboxylic acid may be any of a saturated fatty acid and an unsaturated fatty acid.
In the polycarboxylic acid, the number of carboxyl groups may be 2 or more, and for example, may be 2 to 10 (for example, 2 to 6).
Preferred polycarboxylic acids include those in which carboxyl groups are present relatively densely. In such polycarboxylic acids, the average molecular weight per 1 carboxyl group may be, for example: 100 or less, 80 or less, 60 or less, 50 or less, 40 or less, 35 or less, and the like.
Examples of the polycarboxylic acid (polycarboxylic acid compound) used in the etching solution of the present invention include: alkane polycarboxylic acids (e.g. C, such as oxalic acid, malonic acid, succinic acid, glutaric acid, etc.)2-12Alkanedioic acids), olefinic polycarboxylic acids (e.g. C such as maleic acid, fumaric acid, etc.)4-12Alkene dicarboxylic acids), carboxyalkylamines [ e.g. nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), L-aspartic acid-N, N-diacetic acid (ADSA), diethylenetriaminepentaacetic acid (DTPA)]And their derivatives (salts, etc.). Among these polycarboxylic acids (polycarboxylic acid compounds), malonic acid, maleic acid, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), and salts thereof are more preferable because the liquid crystal polymer is stably removed without residue in the process of removing the liquid crystal polymer, malonic acid, ethylenediaminetetraacetic acid (EDTA), and salts thereof are further preferable, and ethylenediaminetetraacetic acid (EDTA), and salts thereof are particularly preferable. Further, as the polycarboxylic acid (polycarboxylic acid compound), 1 kind may be used alone, or 2 or more kinds may be used in combination.
When the etching liquid contains a polycarboxylic acid, the etching liquid for liquid crystal polymers of the present invention may preferably contain at least 1 or more of the polycarboxylic acid in the above-mentioned proportion (for example, 1 to 60% by mass). The content of the polycarboxylic acid is more preferably 10 to 40% by mass.
(hydroxy acid compound)
The hydroxy acid (hydroxy acid compound) used in the etching solution of the present invention further contains a derivative (e.g., a salt) of the hydroxy acid as described above. As described above, the hydroxy acid and/or the salt thereof may be a hydrate.
The hydroxy acid may be any one of aliphatic hydroxy acid and aromatic hydroxy acid, and the aliphatic hydroxy acid may be any one of saturated fatty acid and unsaturated fatty acid.
In the hydroxy acid, the number of hydroxyl groups may be 1 or more, and for example, may be 1 to 10 (for example, 1 to 5).
In the hydroxy acid, the number of carboxyl groups may be 1 or more, and for example, may be 1 to 10 (for example, 1 to 5).
As the preferred hydroxy acid, compounds in which hydroxyl groups and carboxyl groups are relatively densely present are exemplified. In such hydroxy acids, the average molecular weight to each 1 group in the total amount of hydroxy and carboxy groups may be, for example: 100 or less, 80 or less, 60 or less, 50 or less, 40 or less, 35 or less, and the like.
Examples of the hydroxy acid (hydroxy acid compound) used in the etching solution of the present invention include: aliphatic hydroxy acids [ e.g., hydroxyalkanecarboxylic acids (e.g., glycolic acid, lactic acid, tartronic acid, glyceric acid, leucine, malic acid, tartaric acid, gluconic acid, citric acid, isocitric acid, mevalonic acid (mevalonic acid), Pantoic acid (Pantoic acid), hydroxypentanoic acid, hydroxycaproic acid, etc.), hydroxyalkyl-carboxyalkylamines (e.g., hydroxyethyliminodiacetic acid, hydroxyiminodisuccinic acid, etc.), alicyclic hydroxy acids (e.g., quinic acid), etc. ], aromatic hydroxy acids [ e.g., salicylic acid, 4-hydroxyphthalic acid, 4-hydroxyisophthalic acid, Creosote acid (cresoic acid) (homosalicylic acid, hydroxy (methyl) benzoic acid), vanillic acid, syringic acid, dihydroxybenzoic acid (resorcylic acid), protocatechuic acid, gentisic acid, chromolic acid (orlinic acid), gallic acid, tartronic acid, gluconic acid, glycolic acid, mandelic acid, atrolactic acid, melissic acid, phlorizoic acid (phrenic acid), coumaric acid, umbellic acid, caffeic acid, and the like ], and derivatives (e.g., salts and the like) thereof. Among these hydroxy acids (hydroxy acid compounds), malic acid, tartaric acid, gallic acid, 4-hydroxyisophthalic acid, and salts thereof are more preferable because the liquid crystal polymer is stably removed without leaving a residue in the process of removing the liquid crystal polymer, tartaric acid, 4-hydroxyphthalic acid, and salts thereof are more preferable, and tartaric acid and salts thereof are particularly preferable. As the hydroxy acid, 1 kind may be used alone, or 2 or more kinds may be used in combination.
When the etching liquid contains a hydroxy acid, the etching liquid for liquid crystal polymers of the present invention may preferably contain at least 1 or more of the hydroxy acid in the above-mentioned proportion (for example, 1 to 60 mass%). The content of the hydroxy acid is more preferably 10 to 40 mass%.
In the etching solution of the present invention, a coupling agent, a leveling agent, a coloring agent, a surfactant, an antifoaming agent, an organic solvent, and the like may be added as needed. As the organic solvent, there may be mentioned: ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetates such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, carbitol acetate, etc.; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; amide solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone.
The etching solution of the present invention is preferably an aqueous alkali solution. As water used in the etching solution of the present invention, tap water, industrial water, pure water, or the like can be used. Among them, pure water is preferably used. In the present invention, pure water generally used for industrial use can be used.
< liquid Crystal Polymer >
As the liquid crystal polymer used in the present invention, various liquid crystal polymers such as thermotropic liquid crystal polymers can be used. Examples of such a liquid crystal polymer include liquid crystal polyesters.
Examples of the liquid crystal polyester include: and polyesters containing at least 1 aromatic component selected from aromatic diols, aromatic dicarboxylic acids, aromatic hydroxycarboxylic acids, aromatic diamines [ e.g., diaminobenzene (e.g., 1, 4-diaminobenzene), etc. ], aromatic hydroxyamines [ e.g., aminophenol (e.g., 4-aminophenol), etc. ] and aromatic aminocarboxylic acids [ e.g., aminobenzoic acid (e.g., 4-aminobenzoic acid, etc.) ].
Examples of the aromatic diol include: aromatic diols [ e.g., benzene diol (e.g., 1, 4-hydroxybenzene, 1, 3-dihydroxybenzene, etc.), naphthalene diol (e.g., 2, 6-dihydroxynaphthalene), dihydroxy anthraquinone, etc. ]C6-20Aromatic diols]Biphenol (4, 4-dihydroxybiphenyl, etc.), bisphenolClass [ e.g. bis (hydroxyphenylalkanes) (e.g. bis (hydroxyphenyl C) such as bisphenol F1-10Alkane), etc.), bis (4-hydroxyphenyl) ether, bisphenol S, etc]And the like.
Examples of the aromatic dicarboxylic acid include: c such as an aromatic dicarboxylic acid [ e.g., benzenedicarboxylic acid (e.g., 1, 4-benzenedicarboxylic acid, 1, 3-benzenedicarboxylic acid, etc.), naphthalenedicarboxylic acid (e.g., 2, 6-naphthalenedicarboxylic acid), etc. ]6-20Aromatic dicarboxylic acid]Dicarboxybiphenyl (4, 4-dicarboxybiphenyl, etc.), bis (carboxyphenyl) ether of mono-or polyalkylene glycol, etc]And the like.
Examples of the aromatic hydroxycarboxylic acid include: hydroxy C such as hydroxyaromatic carboxylic acid [ e.g., hydroxybenzoic acid (e.g., p-hydroxybenzoic acid, m-hydroxybenzoic acid), hydroxynaphthoic acid (e.g., 6-hydroxy-2-naphthoic acid) ]6-20Aromatic carboxylic acids]And a hydroxy-carboxybisaryl group (e.g., 4- (4-hydroxyphenyl) benzoic acid, etc.).
The aromatic component may have a substituent { e.g., a halogen atom, an aliphatic group [ e.g., an alkyl group (e.g., C)1-4Alkyl) and the like aliphatic hydrocarbon groups]Aromatic group [ e.g. aromatic hydrocarbon group such as aryl (e.g. phenyl) ]]Etc.. in a similar manner.
In general, a liquid crystal polymer (liquid crystal polyester) often contains at least 1 kind selected from an aromatic diol, an aromatic dicarboxylic acid, and an aromatic hydroxycarboxylic acid as a polymerization component.
The liquid crystal polymer (liquid crystal polyester) may contain, as a polymerization component, a non-aromatic component [ for example, an aliphatic diol (for example, ethylene glycol, polyethylene glycol, or the like), an aliphatic hydroxycarboxylic acid, an aliphatic dicarboxylic acid, or the like ], in addition to the aromatic component.
Typical liquid crystal polymers (liquid crystal polyesters) include, for example, aromatic polyesters synthesized from monomers such as aromatic diols, aromatic carboxylic acids, and hydroxycarboxylic acids, which exhibit liquid crystallinity in the melt, and typical examples thereof include a type 1 liquid crystal polymer (formula 1) composed of p-hydroxybenzoic acid (PHB), terephthalic acid, and biphenol, a type 2 liquid crystal polymer (formula 2) composed of PHB and 6-hydroxy-2-naphthoic acid, and a type 3 liquid crystal polymer (formula 3) composed of PHB, terephthalic acid, and ethylene glycol. m and n represent integers.
[ chemical formula 1]
[ chemical formula 2]
[ chemical formula 3]
To the liquid crystal polymer, thermoplastic polymers such as polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, polyarylate, polyamide, polyphenylene sulfide, polyether ether ketone, and fluorine resin, various additives, fillers, and the like may be added in a range not to impair the effects.
The liquid crystal polymer may contain substantially no filler (organic filler and/or inorganic filler, particularly at least inorganic filler).
In the present invention, the liquid crystal polymer may be bonded to the metal layer. The liquid crystal polymer bonded to the metal layer is obtained by integrating the metal layer and the liquid crystal polymer film by a known or conventional method. For example, a metal foil or the like may be heat-pressed to a liquid crystal polymer film to form a single-sided metal-clad laminate or a double-sided metal-clad laminate, and the metal layer may be further etched as necessary to form a necessary shape of the metal layer.
As the metal forming the metal layer, for example, gold, silver, copper, iron, nickel, aluminum, or an alloy metal thereof, or the like can be used. The thickness of the metal layer can be set as appropriate according to need, and is preferably 5 to 50 μm, and more preferably 8 to 35 μm.
< etching method >
The etching method of the present invention has a step of etching a liquid crystal polymer using the etching solution of the present invention.
In the etching step, the liquid crystal polymer may be etched through the etching resist. As the etching resist, a metal mask may be used. For example, when the metal mask is a copper mask, the copper mask can be manufactured by patterning a copper foil by a copper etching process using, for example, an iron chloride solution, a copper chloride solution, or the like.
In addition, as the etching resist, a dry film resist pattern may be used.
The dry film resist contains at least a photo-crosslinkable resin composition, and is formed by coating a photo-crosslinkable resin on a support film such as polyester to form a photo-crosslinkable resin layer, and optionally covering the photo-crosslinkable resin layer with a protective film such as polyethylene. The photo-crosslinkable resin layer contains, for example, a binder polymer containing a carboxyl group, a photopolymerizable compound having at least 1 ethylenically unsaturated group capable of polymerization in the molecule, a photopolymerization initiator, a solvent, and other additives. The blending ratio of these components is determined by the balance of required properties such as sensitivity, resolution, and degree of crosslinking. Examples of the photo-crosslinkable resin composition are described in "handbook of photopolymer" (edited by the society for photopolymer journal, published by the society for Industrial research, published in 1989), "photopolymer & science & technology" (edited by Shanben Aff, Yongsong Yuan Tailang, published by the society for Industrial journal of Japan), and the like, and a desired photo-crosslinkable resin composition can be used. The thickness of the photo-crosslinkable resin layer is preferably 15 to 100 μm, and more preferably 20 to 50 μm.
As an exposure method of the dry film resist, there are listed: exposure of reflected images using a xenon lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, an ultra-high-pressure mercury lamp, or a UV fluorescent lamp as a light source, close-contact exposure on one side or both sides using a photomask, proximity exposure, projection exposure, and laser scanning exposure. In the case of performing the scanning exposure, the scanning exposure may be performed by performing SHG wavelength conversion on a laser light source such as 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, or by performing the scanning exposure using a liquid crystal shutter or a micromirror array shutter.
As a method for developing the dry film resist, an etching resist formed of a dry film resist pattern is formed by spraying a developer solution corresponding to the used photo-crosslinkable resin layer from the top-bottom direction of the substrate toward the substrate surface to remove unnecessary dry film resist (unexposed portion). As the developer, a 1 to 3 mass% aqueous solution of sodium carbonate is generally used, and a 1 mass% aqueous solution of sodium carbonate is more preferably used.
As a method for removing a dry film resist pattern used as an etching resist, a dry film resist pattern is removed by spraying a stripping liquid matched with a used photo-crosslinkable resin layer from the top-bottom direction of a substrate toward the surface of the substrate. As the stripping liquid, a 2 to 4 mass% aqueous solution of sodium hydroxide is generally used, and a 3 mass% aqueous solution of sodium hydroxide is more preferably used.
As the etching step, there may be used a dipping treatment, a paddle treatment (Japanese text: パドル), a spraying treatment, a brush coating, a scraping treatment, and the like. Among them, the immersion treatment is preferable in view of uniformity of the etching treatment.
In the etching method of the present invention, the temperature of the etching solution is preferably 40 to 100 ℃. The optimum temperature varies depending on the type of liquid crystal polymer, the thickness of a film containing the liquid crystal polymer, the shape of a pattern obtained by the method for etching the liquid crystal polymer, and the like, but the temperature of the etching solution is more preferably 50 to 95 ℃, still more preferably 60 to 90 ℃, and particularly preferably 70 ℃ or higher.
The etching method of the present invention preferably further comprises a pretreatment step of bringing a pretreatment liquid containing 50 to 100 mass% of an alkanolamine compound (usually an ethanolamine compound, particularly an ethanolamine compound having a molecular weight of 70 or more) into contact with the liquid crystal polymer before the etching step. The temperature of the pretreatment solution is preferably 50 ℃ or higher.
The pretreatment step may be carried out by dipping, paddle treatment, spraying, brushing, scraping, or the like. Among them, the dipping treatment is preferable in view of uniformity of the pretreatment.
In the pretreatment, when the treatment time is less than 1 minute, the removability of the surface deposit of the liquid crystal polymer may be insufficient. In addition, if the treatment time exceeds 10 minutes, the dry film resist pattern as an etching resist swells and may not be uniformly treated. The pretreatment time is preferably 1 to 10 minutes, and more preferably 3 to 5 minutes.
The pretreatment liquid preferably contains 50 to 100 mass% of an alkanolamine compound. By adding an alkanolamine compound to the pretreatment liquid, the surface deposits of the liquid crystal polymer can be removed. When the content of the alkanolamine compound is less than 50 mass%, the removability of the surface deposit of the liquid crystal polymer is insufficient, and the effect of swelling the dry film resist becomes large, which causes a problem that uniform treatment is not performed. The content of the alkanolamine compound is more preferably 60 to 100 mass%.
When the content of the alkanolamine compound in the pretreatment is less than 100 mass%, the remaining portion is preferably water. As water used for the pretreatment, tap water, industrial water, pure water, or the like can be used. Among them, pure water is preferably used. In the present invention, pure water generally used for industrial use can be used.
The alkanolamine compound (e.g., ethanolamine compound) may be any of primary amine, secondary amine, tertiary amine, and the like, and 1 species may be used alone or 2 or more species may be used in combination. As examples of typical alkanolamine compounds, there can be mentioned: 2-aminoethanol as a primary amine; 2- (2-aminoethylamino) ethanol as a mixture of primary and secondary amines (i.e., a compound having a primary amino group and a secondary amino group in one molecule); 2- (methylamino) ethanol or 2- (ethylamino) ethanol as a secondary amine; examples of the tertiary amine include 2, 2' -methyliminodiethanol and 2- (dimethylamino) ethanol. Among these, 2- (methylamino) ethanol and 2- (2-aminoethylamino) ethanol are more preferable.
The pretreatment solution of the present invention is preferably used at 50 ℃ or higher. When the temperature of the pretreatment liquid is less than 50 ℃, the removability of the surface attachment of the liquid crystal polymer is insufficient. The temperature of the pretreatment solution is more preferably 60 ℃ or higher. In the case where the etching resist is a dry film resist pattern, swelling of the dry film resist pattern becomes large, and an adverse effect on the etching treatment may be observed, and therefore, the temperature of the pretreatment liquid is preferably 90 ℃ or lower.
In the etching method of the present invention, after the etching step, a water washing step using water washing water (water washing liquid) is preferably performed in order to remove the etching liquid for the liquid crystal polymer remaining adhered to the surface of the liquid crystal polymer. As a method of the water washing treatment, a spraying method is preferable in view of a diffusion rate and uniformity of liquid supply.
As the washing water, tap water, industrial water, pure water, or the like can be used. Among them, pure water is preferably used. As the pure water, pure water generally used for industrial use can be used. The temperature of the washing water is preferably not higher than the temperature of the liquid crystal polymer etching solution.
In the etching method of the present invention, it is more preferable that the washing step includes a first washing step using a first washing liquid and a second washing step using a second washing liquid in this order, and the temperature of the etching liquid-the temperature of the first washing liquid is less than 25 ℃, and the temperature of the first washing liquid-the temperature of the second washing liquid is less than 25 ℃.
By setting the temperature of the etching solution, the temperature of the first water washing solution to be less than 25 ℃ and the temperature of the first water washing solution to be less than 25 ℃, the liquid crystal polymer can be etched without peeling the bonding surface between the metal layer and the liquid crystal polymer when the liquid crystal polymer bonded to the metal layer is etched. When the temperature of the etching solution, i.e., the temperature of the first rinsing solution, is 25 ℃ or higher, peeling of the bonding surface between the metal layer and the liquid crystal polymer may occur at that time. Even if the temperature of the etching solution-the temperature of the first rinsing liquid is less than 25 ℃, peeling of the bonding surface between the metal layer and the liquid crystal polymer may occur when the temperature of the first rinsing liquid-the temperature of the second rinsing liquid is 25 ℃ or higher.
The temperature of each liquid is the temperature of each liquid when it is in contact with the liquid crystal polymer.
In the etching method of the present invention, it is preferable to add an aqueous washing liquid (aqueous washing water) to the etching liquid. In the cleaning step, the liquid crystal polymer remaining on the surface of the liquid crystal polymer is cleaned with an etching solution by a cleaning treatment. When the etching step is continuously performed, the etching process with high in-plane uniformity can be easily maintained by adding cleaning water to the etching solution. The mechanism of this effect is not clear, but it is presumed that the balance of the etching solution broken can be effectively restored by supplementing the etching solution with the washing water containing the etching solution brought out from the etching step to the washing step. Compared with the case where the components (for example, an alkali metal hydroxide, an alkanolamine compound, etc.) in the etching solution are separately supplemented, the liquid crystal polymer after etching has a shape close to the designed shape and has high in-plane uniformity. When the rinsing step includes the first rinsing step and the second rinsing step in this order, it is preferable to add the rinsing liquid (rinsing water) of the first rinsing step to the etching liquid.
Examples
The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.
[ examples 1-1 to 3-16]
[ etching ]
A releasable metal foil was prepared by laminating a thermoplastic liquid crystal polymer film (area: 500 mm. times.500 mm in the transverse direction, thickness: 20 μm) which was a copolymer (molar ratio: 73/27) of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid and had a melting point of 280 ℃ and a thickness of 20 μm, and a copper foil having a thickness of 3 μm, a release layer and a carrier foil in this order, and the copper foil and the liquid crystal polymer film (liquid crystal polymer) were thermocompression bonded to each other so that the copper foil and the liquid crystal polymer film were in contact with each other, and then the release layer and the carrier foil were peeled off to obtain a liquid crystal polymer with copper foil. A liquid crystal polymer film surface of a liquid crystal polymer substrate with a copper foil was roughened, and a dry film resist (DFR, thickness: 30 μm, manufactured by Asahi Kasei Co., Ltd., AQ3058) was laminated thereon as a mask by using a roll laminator under conditions of a temperature of 100 ℃, a speed of 0.5m/min, and a pressure of 0.5 MPa. Then, patterning was performed by exposure, and development was performed with an aqueous sodium carbonate solution to form an opening pattern in a mask. After the formation of the opening pattern, the mask was subjected to exposure processing of 1000 mJ.
Next, the dry film resist having the opening pattern formed thereon was used as a mask, and the liquid crystal polymer film was subjected to immersion treatment at a liquid temperature of 80 ℃ using an etching solution described in tables 1 to 6, thereby forming an opening. After the opening is formed, the dry film resist is peeled off.
[ examples 1-1 to 3-16]
Whether or not the liquid crystal polymer (liquid crystal polymer film) was reliably removed at the opening was evaluated by the "resin residue". In addition, the "undercut (Japanese text: アンダ - カット)" was used to evaluate the deformation in the shape of the opening of the liquid crystal polymer. As an evaluation of "in-plane uniformity", 60 openings located in the plane were observed with the same target opening diameter (target opening diameter), the opening diameter of the opening with the largest opening diameter was set to the "maximum value", the opening diameter of the opening with the smallest opening diameter was set to the "minimum value", and the variation value (%) was obtained by "(maximum value-minimum value)/target opening value × 100", thereby evaluating "in-plane uniformity". In order to evaluate the running property of the etching solution, the same test was performed after using 50 wafers/1 day for a total period of 30 days (about 1.5 months). The results are shown in tables 1 to 6. The criteria for each evaluation are as follows.
Resin residue "
O (excellent): no liquid crystal polymer remained.
Δ (good): a very small amount of liquid crystal polymer remained, but this did not become a problem.
Δ (general): a small amount of liquid crystal polymer remains, but can be easily removed by plasma cleaning treatment.
X (poor): a large amount of liquid crystal polymer remains and cannot be easily removed by plasma cleaning treatment.
[ undercut ]
O (excellent): no undercut was found.
Δ (good): minimal undercutting was found.
Δ (general): small undercuts were found but were not problematic.
X (poor): large undercuts are found to be problematic.
(in-plane uniformity/runnability: evaluation with etching solution before and after running)
O (excellent): the uniformity is very high. The variation is less than 3%.
Δ (good): the uniformity is high. The variation is 3% or more and less than 5%.
Δ (general): and (4) uniformity. The variation is 5% or more and less than 6%.
X (poor): is not uniform. The variation value is 6% or more.
[ Table 1]
[ Table 2]
[ Table 3]
[ Table 4]
[ Table 5]
[ Table 6]
From the results in tables 1 to 6, it is understood that when the etching solution of the present invention is used, the undercut is small, and the shape of the liquid crystal polymer after etching is close to the design shape. Further, it was found that etching can be performed with high in-plane uniformity. Further, it is found that the etching solution of the present invention containing 1 to 60 mass% of the 3 rd component is excellent in running property.
Examples 4-1 to 4-19
A releasable metal foil was prepared by laminating a thermoplastic liquid crystal polymer film (area: 500 mm. times.500 mm in the transverse direction, thickness: 20 μm) having a melting point of 280 ℃ and a thickness of 20 μm as a copolymer (molar ratio: 73/27) of PHB (p-hydroxybenzoic acid) and 6-hydroxy-2-naphthoic acid, and a copper foil having a thickness of 3 μm, a release layer and a carrier foil in this order, and the copper foil and the liquid crystal polymer were thermocompression bonded to each other so as to be in contact with each other, and then the release layer and the carrier foil were peeled off to obtain a liquid crystal polymer with a copper foil. A liquid crystal polymer surface of a liquid crystal polymer substrate with a copper foil was roughened, and a dry film resist (DFR, thickness: 30 μm, manufactured by Asahi Kasei Co., Ltd., AQ3058) was laminated thereon as a mask by using a roll laminator under conditions of a temperature of 100 ℃, a speed of 0.5m/min, and a pressure of 0.5 MPa. Then, patterning was performed by exposure, and development was performed with a 1 mass% aqueous solution of sodium carbonate to form a dry film resist pattern having an opening pattern. After the opening pattern was formed, an exposure process of 1000mJ was performed on the dry film resist pattern.
Next, the pretreatment liquids described in tables 1 and 2 were brought into contact with each other through a dry film resist pattern for 3 minutes, and immersion treatment was performed using the etching liquid described in table 1 (temperature 80 ℃) to form an opening in the liquid crystal polymer. After the opening portion is formed, the dry film resist pattern is peeled off.
The time required for etching to the bottom surface of the opening (the bottom surface of the liquid crystal polymer in the opening) was evaluated as "etching time". In this example, if productivity is taken into consideration, the etching time is preferably 50 minutes or less, more preferably 40 minutes or less, and still more preferably 30 minutes or less. In addition, reproducibility of the shape of the opening of the liquid crystal polymer after etching with respect to the shape of the opening of the dry film resist pattern was evaluated as an "opening shape". The results are shown in Table 7.
Evaluation criteria of the opening shape are shown below.
O (excellent): the shape is not deformed.
Δ (good): there is a slight deformation in the shape.
Δ (general): the shape is deformed but not problematic.
X (poor): the shape is deformed, which becomes a problem.
[ Table 7]
From the results in table 7, it is understood that the etching method further comprising a pretreatment step of bringing a pretreatment liquid containing 50 to 100 mass% of an alkanolamine compound into contact with the liquid crystal polymer before the etching step shortens the time required for etching. In addition, it is found that the reproducibility of the opening shape is also improved.
Examples 5-1 to 5-36
[ etching ]
A thermoplastic liquid crystal polymer film (area: 500 mm. times.500 mm in the transverse direction, thickness: 20 μm) having a melting point of 280 ℃ and a thickness of 20 μm, which was a copolymer of PHB and 6-hydroxy-2-naphthoic acid (molar ratio: 73/27), and a copper foil having a thickness of 18 μm were prepared, and the two were thermocompression bonded so that the copper foil was in contact with the liquid crystal polymer to obtain a liquid crystal polymer substrate with a copper foil.
The liquid crystal polymer surface of the liquid crystal polymer substrate with copper foil was roughened, and a dry film resist (DFR, thickness: 30 μm, manufactured by Asahi chemical Co., Ltd., ASG-302) was laminated thereon using a roll laminator under conditions of a temperature of 100 ℃, a speed of 0.5m/min, and a pressure of 0.5 MPa. Then, patterning was performed by exposure, and development was performed with a 1 mass% aqueous solution of sodium carbonate to form a dry film resist pattern having an opening pattern. After forming the opening pattern, a dry film resist pattern was subjected to 1000mJ/cm2And (4) exposure processing.
Next, using the dry film resist pattern having the opening pattern as a mask, an etching step by immersion treatment was performed at an etching temperature shown in table 9 using an etching solution shown in table 8, and a first rinsing step and a second rinsing step by spraying treatment were performed at temperatures shown in table 2 using a first rinsing solution and a second rinsing solution, thereby forming openings in the liquid crystal polymer film. After the opening was formed, the dry film resist pattern was peeled off to obtain a test material.
(presence or absence of peeling at the interface between the liquid crystal polymer and the metal layer)
The test materials obtained in the respective examples were embedded in an acrylic resin, and then cut and polished to prepare test pieces for cross-section observation. The cross section of the liquid crystal polymer bonded to the metal layer was observed by an optical microscope to confirm whether or not peeling occurred at the bonding surface between the liquid crystal polymer and the metal layer. The results are shown in Table 9.
[ Table 8]
[ Table 9]
As is clear from the results in table 9, in the etching method of the present invention in which the etching step is further followed by a washing step using a washing liquid, the washing step includes a first washing step using a first washing liquid and a second washing step using a second washing liquid in this order, and the temperature of the etching liquid-the temperature of the first washing liquid is less than 25 ℃, and the temperature of the first washing liquid-the temperature of the second washing liquid is less than 25 ℃, peeling of the bonding surface between the metal layer and the liquid crystal polymer is less likely to occur.
Examples 6-1 to 6-28
[ etching ]
A metal foil was prepared by laminating a thermoplastic liquid crystal polymer (area: 500 mm. times.500 mm in the transverse direction, thickness: 20 μm) having a melting point of 280 ℃ and a thickness of 20 μm, which was a copolymer of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid (molar ratio: 73/27), and a copper foil having a thickness of 3 μm, a release layer and a carrier foil in this order. After a thermoplastic liquid crystal polymer and a metal foil were thermally pressure-bonded so that a copper foil was brought into contact with the liquid crystal polymer, the release layer and the carrier foil were peeled off to obtain a liquid crystal polymer substrate with a copper foil (liquid crystal polymer to which a metal layer was bonded).
The liquid crystal polymer surface of the liquid crystal polymer substrate with copper foil was roughened, and a dry film resist (DFR, thickness: 30 μm, manufactured by Asahi chemical Co., Ltd., ASG-302) was laminated thereon using a roll laminator under conditions of a temperature of 100 ℃, a speed of 0.5m/min, and a pressure of 0.5 MPa. Then, a dry film resist pattern (etching resist) having an opening portion was formed by exposure and development with a 1 mass% sodium carbonate aqueous solution. The dry film resist pattern was subjected to a re-exposure process of 1000 mJ.
Next, an etching solution described in table 10 was used, and immersion treatment was performed at a liquid temperature of 80 ℃ through the etching resist to form an opening in the liquid crystal polymer, and then the dry film resist pattern was peeled off using a 3 mass% aqueous solution of sodium hydroxide.
In order to evaluate the running performance of the etching solution, only the etching solution from which the liquid crystal polymer was surely removed from the opening was treated randomly for 1 to 50 sheets/1 day, and the total amount was used for 60 days (about 3 months), and the change in the shape of the opening was observed every 30 days.
[ method for replenishing etching solution: operating conditions ]
(I) Examples 6-1, 5, 9, 13, 17, 21 and 25, 100ml/m was supplemented in proportion to the treated area2The etching solution of (3). The liquid level is not replenished so that the liquid level is constant.
(II) examples 6-2, 6, 10, 14, 18, 22 and 26 supplemented with 100ml/m in proportion to the treated area2The etching solution of (3). The rinsing liquid immediately after the etching step is replenished as a liquid surface replenishment.
(III) examples 6-3, 7, 11, 15, 19, 23 and 27, 100ml/m was supplemented in proportion to the treated area2The etching solution of (3). Then, water (pure water) is added as a liquid surface supplement.
(IV) examples 6-4, 8, 12, 16, 20, 24 and 28 supplemented with 100ml/m in proportion to the treated area2The etching solution of (3). Furthermore, it is possible to provide a liquid crystal display device,the etching solution is replenished as a liquid surface replenishment.
As for the aperture shape of the liquid crystal polymer, "aperture diameter" and "in-plane uniformity" were evaluated. The opening diameters were measured at 60 openings on the plane, and the average value was calculated. Then, the amount of change in the opening diameter every 30 days was determined by comparison with that before the start of the operation, and the evaluation was performed according to the following evaluation criteria. In addition, regarding the in-plane uniformity, the aperture diameter to be the target (target aperture diameter) was the same, the aperture at 60 positions in the plane was observed, the aperture diameter of the aperture having the largest aperture diameter was set to the "maximum value", the aperture diameter of the aperture having the smallest aperture diameter was set to the "minimum value", the variation value (%) was obtained by "(maximum value-minimum value)/aperture target value × 100", the variation value (%) was obtained by comparison with the variation value before the start of operation every 30 days, and the evaluation was performed according to the following evaluation criteria.
(evaluation of operability: opening diameter)
O (good): the variation is less than 4%
Δ (general): the variation is more than 4 percent and less than 7 percent
X (poor): the variation is more than 7%
(evaluation of running Property: in-plane uniformity)
O (good): the uniformity is very high. The variation is less than 5%.
Δ (general): and (4) uniformity. The variation is more than 5 percent and less than 6 percent
X (poor): it cannot be said that it is uniform. The variation is more than 6%.
[ Table 10]
As is clear from the results in table 10, in the etching method of the present invention in which the etching step is further followed by a water washing step using a water washing liquid and the water washing liquid is replenished into the etching liquid, the shape of the liquid crystal polymer after etching is close to the design shape even when etching is continuously performed. Further, it was found that etching can be performed with high in-plane uniformity.
Availability in industry
The etching solution for liquid crystal polymer of the present invention can be used for roughening a liquid crystal polymer film, and can be used for etching a resin composition layer containing a liquid crystal polymer and having excellent heat resistance, dielectric properties, mechanical strength, chemical resistance, and the like. For example, the resin composition can be applied to microfabrication of insulating resins in multilayer build-up wiring boards, component-embedded module substrates, flip chip package substrates, package substrate mounting motherboards, and the like.
Claims (15)
1. An etching solution for liquid crystal polymers, characterized in that the etching solution contains 5-45 mass% of alkali metal hydroxide as a component 1 and 5-80 mass% of alkanolamine compound with molecular weight of 70 or more as a component 2.
2. The etching solution for liquid crystal polymers according to claim 1, further comprising 1 to 60 mass% of a 3 rd component, wherein the 3 rd component contains at least 1 selected from an alcohol compound and a carboxylic acid compound.
3. The etching solution for liquid crystal polymers according to claim 2, wherein the 3 rd component contains at least 1 selected from the group consisting of a polyol compound, a polycarboxylic acid compound and a hydroxy acid compound.
4. The etching solution according to claim 2 or 3, wherein the 3 rd component contains a polyol compound.
5. The etching solution according to claim 3 or 4, wherein the molecular weight of the polyol compound is 80 or more and 200 or less.
6. The etching solution according to any one of claims 3 to 5, wherein the polyol compound has 3 or more hydroxyl groups.
7. The etching solution according to any one of claims 3 to 6, wherein the polyol compound contains glycerol.
8. The etching solution according to any one of claims 2 to 7, wherein the 3 rd component contains a polycarboxylic acid compound.
9. The etching solution according to any one of claims 2 to 8, wherein the 3 rd component contains a hydroxy acid compound.
10. A method for etching a liquid crystal polymer, comprising an etching step of etching the liquid crystal polymer using the etching solution according to any one of claims 1 to 9.
11. The method for etching a liquid crystal polymer according to claim 10, further comprising a pretreatment step of bringing a pretreatment liquid containing 50 to 100 mass% of the alkanolamine compound into contact with the liquid crystal polymer before the etching step.
12. The method for etching a liquid crystal polymer according to claim 11, wherein the temperature of the pretreatment liquid is 50 ℃ or higher.
13. The method for etching a liquid crystal polymer according to any one of claims 10 to 12, wherein the etching method further comprises a water washing step using a water washing liquid after the etching step.
14. The method for etching a liquid crystal polymer according to claim 13, wherein the water washing step includes a first water washing step using a first water washing liquid and a second water washing step using a second water washing liquid in this order, and the temperature of the etching liquid-the temperature of the first water washing liquid is less than 25 ℃, and the temperature of the first water washing liquid-the temperature of the second water washing liquid is less than 25 ℃.
15. The method for etching a liquid crystal polymer according to claim 13 or 14, wherein a water washing liquid is supplemented to the etching liquid.
Applications Claiming Priority (11)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2019-071038 | 2019-04-03 | ||
| JP2019071038 | 2019-04-03 | ||
| JP2019116919 | 2019-06-25 | ||
| JP2019-116918 | 2019-06-25 | ||
| JP2019116918 | 2019-06-25 | ||
| JP2019-116919 | 2019-06-25 | ||
| JP2019-211152 | 2019-11-22 | ||
| JP2019211152 | 2019-11-22 | ||
| JP2019-226662 | 2019-12-16 | ||
| JP2019226662 | 2019-12-16 | ||
| PCT/JP2020/013370 WO2020203563A1 (en) | 2019-04-03 | 2020-03-25 | Etching liquid for liquid crystal polymer and method for etching liquid crystal polymer |
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| CN113614204A true CN113614204A (en) | 2021-11-05 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202080022278.2A Pending CN113614204A (en) | 2019-04-03 | 2020-03-25 | Etching solution for liquid crystal polymer and etching method for liquid crystal polymer |
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| Country | Link |
|---|---|
| JP (1) | JP6805397B1 (en) |
| KR (1) | KR102364004B1 (en) |
| CN (1) | CN113614204A (en) |
| TW (1) | TW202104552A (en) |
| WO (1) | WO2020203563A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113348226A (en) * | 2019-01-28 | 2021-09-03 | 三菱制纸株式会社 | Etching solution and etching method for resin composition |
| CN115011348A (en) * | 2022-06-30 | 2022-09-06 | 湖北兴福电子材料有限公司 | Aluminum nitride etching solution and application thereof |
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| TW200724650A (en) * | 2005-11-28 | 2007-07-01 | 3M Innovative Properties Co | Polymer etchant and method of using same |
| JPWO2018186362A1 (en) * | 2017-04-06 | 2020-01-16 | 三菱製紙株式会社 | Etching solution for resin composition and etching method |
| CN112912466A (en) * | 2018-10-24 | 2021-06-04 | 三菱制纸株式会社 | Etching solution and etching method for resin composition |
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| JP2001310959A (en) * | 2000-02-23 | 2001-11-06 | Toray Ind Inc | Liquid etchant for wet-etching resin membrane and etching process using the same |
| JP3438023B2 (en) * | 2000-03-14 | 2003-08-18 | 独立行政法人産業技術総合研究所 | Rotaxane spherical aggregate and method for producing the same, and rotaxane spherical polymer and method for producing the same |
| JP2001358428A (en) * | 2000-06-14 | 2001-12-26 | Toray Ind Inc | Etching method |
| JP2002020513A (en) | 2000-07-06 | 2002-01-23 | Toray Ind Inc | Method for etching |
| US6403211B1 (en) | 2000-07-18 | 2002-06-11 | 3M Innovative Properties Company | Liquid crystal polymer for flexible circuits |
| US6696163B2 (en) * | 2000-07-18 | 2004-02-24 | 3M Innovative Properties Company | Liquid crystal polymers for flexible circuits |
| JP2002184816A (en) * | 2000-12-11 | 2002-06-28 | Toray Ind Inc | Method of etching resin film |
| JP2003261699A (en) * | 2002-03-08 | 2003-09-19 | Toray Eng Co Ltd | Etching solution for liquid crystal polymer and etching method using the same |
| JP4104154B2 (en) * | 2005-03-31 | 2008-06-18 | 東レエンジニアリング株式会社 | Liquid crystal polymer etching solution and liquid crystal polymer etching method. |
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2020
- 2020-03-25 JP JP2020541607A patent/JP6805397B1/en active Active
- 2020-03-25 CN CN202080022278.2A patent/CN113614204A/en active Pending
- 2020-03-25 KR KR1020217030734A patent/KR102364004B1/en active IP Right Grant
- 2020-03-25 WO PCT/JP2020/013370 patent/WO2020203563A1/en active Application Filing
- 2020-03-31 TW TW109111011A patent/TW202104552A/en unknown
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| US3481877A (en) * | 1967-02-27 | 1969-12-02 | Amchem Prod | Cleaning solution concentrate and method of preparing same |
| TW200724650A (en) * | 2005-11-28 | 2007-07-01 | 3M Innovative Properties Co | Polymer etchant and method of using same |
| JPWO2018186362A1 (en) * | 2017-04-06 | 2020-01-16 | 三菱製紙株式会社 | Etching solution for resin composition and etching method |
| CN112912466A (en) * | 2018-10-24 | 2021-06-04 | 三菱制纸株式会社 | Etching solution and etching method for resin composition |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113348226A (en) * | 2019-01-28 | 2021-09-03 | 三菱制纸株式会社 | Etching solution and etching method for resin composition |
| CN115011348A (en) * | 2022-06-30 | 2022-09-06 | 湖北兴福电子材料有限公司 | Aluminum nitride etching solution and application thereof |
| CN115011348B (en) * | 2022-06-30 | 2023-12-29 | 湖北兴福电子材料股份有限公司 | Aluminum nitride etching solution and application thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20210121292A (en) | 2021-10-07 |
| WO2020203563A1 (en) | 2020-10-08 |
| JPWO2020203563A1 (en) | 2021-04-30 |
| TW202104552A (en) | 2021-02-01 |
| KR102364004B1 (en) | 2022-02-16 |
| JP6805397B1 (en) | 2020-12-23 |
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