TW202028428A - Etching solution for resin composition and etching method - Google Patents

Abstract

The present invention is an etching solution for a resin composition containing an alkali-insoluble resin and 50 to 80% by mass of an inorganic filler, wherein the etching solution contains 15 to 45% by mass of an alkali metal hydroxide as a first component, 1 to 40% by weight of an ethanolamine compound as a second component, and 3 to 60% by weight of a polyol compound, 2 to 20% by weight of a polycarboxylic acid or 2 to 20% by weight of hydroxy acid as a third component.

Description

Etching solution and etching method of resin composition

The present invention relates to an etching solution and an etching method for a resin composition, the resin composition containing an alkali-insoluble resin and 50 to 80% by mass of an inorganic filler.

In recent years, with the miniaturization and high performance of electronic equipment, there is a strong demand for the formation of micro wiring and the reduction of the thermal expansion coefficient for the circuit board system. Among them, a method for lowering the coefficient of thermal expansion of an insulating material is known to be a method of highly filling the insulating material, that is, increasing the content of the inorganic filler of the insulating material. Furthermore, there is a proposal to use an alkali-insoluble resin that contains epoxy resin, phenol novolak-based hardener, phenoxy resin, cyanate resin, etc. as an insulating material and has excellent moisture resistance. These insulating resin compositions containing inorganic fillers and alkali-insoluble resins have excellent physical properties such as heat resistance, dielectric properties, mechanical strength, and chemical resistance, and are widely used as the outer surface of circuit boards The solder resist and interlayer insulating material that can be used in multilayer build-up wiring boards.

FIG. 1 is a schematic cross-sectional structure diagram of the solder resist pattern after covering the circuit board with the resin composition layer 4 except for the connection pad 3 to be soldered. The structure shown in FIG. 1 is called an SMD (Solder Masked Defined) structure, and is characterized in that the opening of the resin composition layer 4 is smaller than the connection pad 3. The structure shown in Figure 2 is called NSMD (Non Solder The MaskedDefined (no solder mask limitation) structure is characterized in that the opening of the resin composition layer 4 is larger than the connection pad 3.

The opening of the resin composition layer 4 in Figure 1 is formed by removing part of the resin composition layer. Regarding the processing method for removing the resin composition layer containing the resin composition containing inorganic filler and alkali-insoluble resin, drilling processing, laser processing, plasma processing, sandblasting, etc. can be used Well-known method. Moreover, these methods can also be combined as needed. Among them, the most common is the processing by carbon dioxide lasers, excimer lasers, UV lasers, YAG lasers and other lasers. By irradiating laser light, a part of the resin composition layer 4 can be removed to form through holes for forming through holes, openings for forming via holes, openings for forming connection pads 3, etc. Holes and non-through holes (for example, refer to Patent Documents 1 and 2).

However, in the processing by irradiating laser light, for example, in the case of using a carbon dioxide laser, more irradiation times are required, and post-processing must be performed with an oxidizing agent in an aqueous solution containing chromic acid, permanganate, etc. Desmear treatment. In addition, in the case of using an excimer laser, the time required for processing becomes very long. Moreover, in the case of UV-YAG lasers, compared to other lasers, it has advantages in terms of microfabrication, but it not only removes the resin composition layer, but also removes the nearby metal layer. The problem.

Moreover, if the laser light is irradiated on the resin composition layer, the light at the irradiated part can be absorbed by the object, and the object will excessively generate heat due to specific heat, and this heat will cause the resin to dissolve, deform, change, and change color. And other shortcomings. Furthermore, for such heat generation, although it has been proposed to use a thermosetting resin in the resin composition layer, if a thermosetting resin is used, cracks may easily occur in the resin composition layer.

As a method other than irradiating laser light, a method of removing the resin composition layer by a wet blast method can be cited. After forming a resin composition layer on a circuit board with connection pads on an insulating substrate, curing is performed, and a resin layer for forming a wet sandblasting mask is placed on the resin composition layer, and then exposed and developed , Thereby forming a patterned wet sandblasting mask. Next, the resin composition layer is removed by performing wet blasting to form an opening, and then the wet blasting mask is removed (for example, refer to Patent Document 3).

However, in the processing performed by wet sandblasting, the thickness that can be polished by one sandblasting treatment is small, and the sandblasting treatment must be repeated several times. Therefore, not only does the polishing time take very long, but also the part that adheres to the resin composition layer is on the connection pad or on the insulating substrate. The material may not be uniformly polished or appear It is extremely difficult to perform high-precision processing.

Regarding the processing method of removing the resin composition layer containing the resin composition containing the inorganic filler and the alkali-insoluble resin, it is disclosed that the hydrazine-based chemical solution at 40°C is used as the etching solution, and the dipping treatment A method of etching (for example, refer to Patent Document 4). However, hydrazine is a toxic substance and has a large impact on the human body and environmental load, so it is not good.

In addition, an etching method using an etching solution containing 15 to 45% by mass of alkali metal hydroxide has been disclosed (for example, refer to Patent Document 5). Patent Document 5 also discloses that a more preferable aspect is an etching solution containing an ethanolamine compound.

Although the etchant of Patent Document 5 has a small impact on the human body and environmental load, there are cases where residues appear on the surface after etching. Moreover, undercuts may be found in the resin composition layer after etching. In addition, in the etching process with high productivity, it is important to arrange several patterns in the surface and process each pattern uniformly. However, in recent years, the density of substrates has increased. It is expected to be better than the previous microfabrication, and at the same time, its uniformity will be required, so it is not enough to meet the requirements.

Furthermore, when the resin composition layer is etched in accordance with the etching method disclosed in Patent Document 5, since the affinity between the etching solution and the resin composition layer is insufficient, the opening of the resin composition layer is to be opened In the small-diameter opening treatment with a diameter of less than Φ100μm, there may be unetched areas. Therefore, an etching method that does not produce unetched areas is required.

[Prior Technical Literature]

[Patent Literature]

[Patent Document 1] JP 2003-101244 A

[Patent Document 2] International Publication No. 2017/38713 Pamphlet

[Patent Document 3] JP 2008-300691 A

[Patent Document 4] International Publication No. 2018/88345 Pamphlet

[Patent Document 5] International Publication No. 2018/186362 Pamphlet

The subject of the present invention is to provide an etching solution and an etching method for a resin composition. The etching solution is stable and free of residues during the process of removing the resin composition containing alkali-insoluble resin and inorganic filler using the etching solution. The resin composition layer containing the resin composition is removed, and the resin composition layer after etching is not prone to welding corrosion and has high in-plane uniformity. Furthermore, this hair Another issue of the Ming is to provide an etching method that can suppress the occurrence of unetched areas even in small-diameter opening treatments where the opening diameter is to be Φ100 μm or less.

The inventors of the present invention found that the above-mentioned problems can be solved by the following means.

<1> An etching solution of a resin composition, the resin composition comprising an alkali-insoluble resin and 50 to 80% by mass of an inorganic filler, wherein the etching solution contains 15 to 45% by mass of an alkali metal as the first component Hydroxide, and 1 to 40% by mass of ethanolamine compound as the second component, and containing 3 to 60% by mass of polyol compound, 2 to 20% by mass of polycarboxylic acid or 2 to 20% by mass of the third component % Hydroxy acid.

<2> The etching solution of the resin composition according to <1>, wherein the third component is 3 to 60% by mass of a polyol compound.

<3> The resin composition etching solution according to <1> or <2>, wherein the molecular weight of the polyol compound is 80 or more and 200 or less.

<4> The etching liquid of the resin composition according to any one of <1> to <3>, wherein the polyol compound has 3 or more hydroxyl groups.

<5> The resin composition etching liquid according to any one of <1> to <4>, wherein the polyol compound is glycerin.

<6> The etching solution of the resin composition according to <1>, wherein the third component is 2 to 20% by mass of polycarboxylic acid.

<7> The etching solution of the resin composition according to <1>, wherein the third component is 2 to 20% by mass of hydroxy acid.

<8> An etching method of a resin composition, which has the following steps: using the etching solution of the resin composition described in any one of <1> to <7>, for the etching solution containing alkali-insoluble resin and 50 to 80% by mass The resin composition of the inorganic filler is etched.

<9> The etching method of the resin composition as described in <8>, after the etching treatment step, further has an ultrasonic irradiation step.

<10> The etching method of the resin composition as described in item <8> or <9>, before the etching treatment step, further has a pretreatment step with a pretreatment liquid, the pretreatment liquid containing 2.5 An acidic aqueous solution of an anionic surfactant to 7.5% by mass.

<11> The etching method of the resin composition according to any one of <8> to <10>, wherein an etching resist is used in the etching treatment step, and the etching resist is a metal mask or a dry film photoresist (Dry-Film Resist).

According to the present invention, it is possible to provide an etching solution and an etching method for a resin composition. In the process of removing the resin composition containing alkali-insoluble resin and inorganic filler using the etching solution, the resin containing the resin can be removed stably without residue The resin composition layer formed by the composition, and the resin composition layer after etching is one that is not prone to welding corrosion and has high in-plane uniformity. Furthermore, it is possible to provide an etching method that can suppress the occurrence of unetched areas even in small-diameter opening treatments where the opening diameter is to be Φ100 μm or less.

1: Circuit board

1’: Copper clad laminate

2: insulation layer

3: Welding pad, connecting pad

3’: Copper foil

4: Resin composition layer

5: Etching resist (metal mask, dry film photoresist pattern)

6: Copper foil, dry film photoresist

7: Evaluation section

A: Conductor pattern

a: The opening length of the etching resist 5

b: Film thickness of resin composition layer 4

c: the bottom length of the resin composition layer 4

d: opening

Figure 1 is a schematic cross-sectional structure diagram of a solder resist pattern.

Figure 2 is a schematic cross-sectional structure diagram of the solder resist pattern.

FIG. 3 is a cross-sectional step diagram showing an example of the step of etching the resin composition layer 4 by the etching method of the present invention.

The embodiments of the present invention will be described below. In addition, in this specification, the "etching liquid of the resin composition" may be abbreviated as the "etching liquid", and the "etching method of the resin composition" may be abbreviated as the "etching method".

The etching method of the present invention has the following steps: using the etching solution of the present invention, a resin composition containing an alkali-insoluble resin and 50 to 80% by mass of an inorganic filler is subjected to etching treatment.

The etching solution of the present invention contains 15 to 45% by mass of alkali metal hydroxide as the first component. Since alkali-insoluble resin has the property of not being dissolved in alkaline aqueous solution, it cannot be removed by alkaline aqueous solution. However, by using the etching solution of the present invention, the resin composition containing alkali-insoluble resin can be removed. This is because the highly filled inorganic filler in the resin composition (that is, the inorganic filler filled in the resin composition with a content as high as 50 to 80% by mass) will be contained in a high concentration of alkali metal hydroxide. The aqueous solution of the substance is dissolved and dispersed and removed.

When the content of alkali metal hydroxide is 15% by mass or more, the solubility of the inorganic filler is excellent; when the content of alkali metal hydroxide is 45% by mass or less, it is difficult to cause precipitation of alkali metal hydroxide , So the solution has excellent stability over time. The content of alkali metal hydroxide is more preferably 20 to 45% by mass.

The alkali metal hydroxide can suitably use at least one compound selected from the group of potassium hydroxide, sodium hydroxide, and lithium hydroxide. The alkali metal hydroxide may be used alone or in combination of two or more.

The etching solution of the present invention contains 1 to 40% by mass of ethanolamine compound as the second component. When the etching solution contains the ethanolamine compound, the ethanolamine compound penetrates into the resin composition, swells the resin composition, and dissolves the inorganic filler uniformly. When the content of the ethanolamine compound is 1% by mass or more, the alkali-insoluble resin has excellent swelling properties; when the content is less than 40% by mass, the compatibility with water becomes higher, and phase separation becomes less likely to occur. Excellent stability. The content of the ethanolamine compound is more preferably 3 to 35% by mass.

The above-mentioned ethanolamine compound may be any one of primary amine, secondary amine, tertiary amine, etc., and may be used alone or in combination of two or more. An example of a representative amine compound can include: 2-aminoethanol which is a primary amine; a mixture of a primary amine and a secondary amine (that is, a compound having a primary amine group and a secondary amine group in one molecule) 2-(2-aminoethylamino)ethanol; 2-(methylamino)ethanol and 2-(ethylamino)ethanol which are secondary amines; 2,2'- which are tertiary amines Methyliminodiethanol or N,N-dimethylaminoethanol, etc. Among them, 2-(methylamino)ethanol and 2-(2-aminoethylamino)ethanol are more preferable.

The etching solution of the present invention contains 3 to 60% by mass of polyol compound, 2 to 20% by mass of polycarboxylic acid, or 2 to 20% by mass of hydroxy acid as the third component. By making the etching solution of the present invention contain a polyol compound and a polycarboxylic acid or a hydroxy acid, the alkali-insoluble resin and the dissolved inorganic filler can be dispersed and removed simultaneously.

Although the mechanism of this effect is still speculative, it is believed to be related to the dissolution, dispersion and removal mechanism of the etching solution in this case. In order to remove the resin composition stably by etching, it is necessary to dissolve part or all of the highly filled inorganic filler in the resin composition in an etching solution containing a high concentration of alkali metal hydroxide, and it cannot be used in the resin composition. The alkali-insoluble resin and the dissolved inorganic filler are removed at the same time while maintaining the shape of the film. When only one component is removed, the other The branch will become a residue and remain on the surface after etching. It is believed that by making the etching solution contain a polyhydric alcohol compound and a polycarboxylic acid or a hydroxy acid, it has the function of integrating the components that cannot maintain the shape of the film, thereby improving the performance of simultaneous removal. It is believed that with this effect, no residue remains and the processing time margin is increased, and the resin composition containing alkali-insoluble resin and a large amount of inorganic filler can be stably removed.

If the content of the polyol compound used in the etching solution of the present invention is less than 3% by mass, the integration and dispersion performance will become insufficient, and if it exceeds 60% by mass, the integration will be excessive and the removability will become insufficient. The content of the polyol compound is more preferably 10 to 40% by mass.

The polyol compound used in the etching solution of the present invention has a preferable molecular weight range, and more than 80 and less than 200 are preferable. Moreover, the polyol compound is preferably a compound having 3 or more hydroxyl groups. Specific examples include glycerin, neopentylerythritol, sorbitol, xylitol, volemitol, diethylene glycol, and ethylene glycol. Among them, glycerin is particularly preferred. Moreover, a polyol compound may be used individually by 1 type, and may be used in combination of 2 or more types.

When the content of the polycarboxylic acid used in the etching solution of the present invention is less than 2% by mass, the integration and dispersion performance will become insufficient, and when it exceeds 20% by mass, the integration will be excessive and the removability will become insufficient. The content of the polycarboxylic acid is more preferably 3 to 15% by mass. The polycarboxylic acids that can be used in the etching solution of the present invention also include salts of polycarboxylic acids.

The polycarboxylic acids used in the etching solution of the present invention can be exemplified: oxalic acid, malonic acid, succinic acid, glutaric acid, maleic acid, nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid ( EDTA), L-aspartic acid-N,N-diacetic acid (ADSA), diethylenetriaminepentaacetic acid (DTPA) and these salts. In the process of removing the resin composition containing the alkali-insoluble resin and the inorganic filler, in order to remove the resin composition layer containing the resin composition without residue and stably remove, among these polycarboxylic acids, propylene is particularly preferred. Diacid, maleic acid, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA) And these salts are more preferable, malonic acid and ethylenediaminetetraacetic acid (EDTA) and these salts are even more preferable, and ethylenediaminetetraacetic acid (EDTA) and its salts are particularly preferable. Moreover, a polycarboxylic acid may be used individually by 1 type, and may be used in combination of 2 or more types.

When the content of the hydroxy acid used in the etching solution of the present invention is less than 2% by mass, the integration and dispersion performance will become insufficient, and when it exceeds 20% by mass, the integration will be excessive and the removability will become insufficient. The content of hydroxy acid is more preferably 3 to 15% by mass. The hydroxy acid used in the etching solution of the present invention also includes a salt of hydroxy acid. Furthermore, the salt of hydroxy acid may be a hydrate.

The hydroxy acids used in the etching solution of the present invention can be exemplified: glycolic acid, lactic acid, hydroxymalonic acid, glyceric acid, leucic acid, malic acid, tartaric acid, gluconic acid, citric acid, isocitric acid, methyl Mevalonic acid (mevalonic acid), pantoic acid (pantoic acid), hydroxyethyl imino diacetic acid, hydroxy imino disuccinic acid, quinic acid (quinic acid), salicylic acid, 4-hydroxy ortho Phthalic acid, 4-hydroxyisophthalic acid, lignooleic acid (salicylic acid, hydroxy(methyl)benzoic acid), vanillic acid, syringic acid, hydroxyvaleric acid, hydroxycaproic acid, lanosol Resorcylic acid, protocatechoic acid, gentisic acid, orsellinic acid, gallic acid, mandelic acid, 2-phenyllactic acid (atrolactinic acid), grass Melilotic acid, phloretic acid, Coumaric acid, umbellic acid, caffeic acid, etc., and their salts. In the process of removing the resin composition containing the alkali-insoluble resin and the inorganic filler, in order to remove the resin composition layer containing the resin composition without residue and stably remove, among these hydroxy acids, apples are particularly preferred. Acid, tartaric acid, gallic acid, 4-hydroxyisophthalic acid and these salts are more preferred, tartaric acid and 4-hydroxyphthalic acid and these salts are even more preferred, and tartaric acid and its salts are preferred Especially good. Furthermore, hydroxy acids may be used singly or in combination of two or more.

In the etching solution of the present invention, coupling agents, leveling agents, coloring agents, surfactants, defoamers, organic solvents, etc. can also be appropriately added as needed. Examples of organic solvents include: ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetic acid such as ethyl acetate, butyl acetate, cellulose acetate, propylene glycol monomethyl ether acetate, carbitol acetate, etc. Esters; carbitols such as celluloid and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc. Amide solvents, etc.

The etching solution of the present invention is preferably an alkaline aqueous solution. As for the water used in the etching solution of the present invention, tap water, industrial water, pure water, etc. can be used. Among them, it is preferable to use pure water, and in general, pure water for industrial use can be used.

The etching solution of the present invention is an etching solution of a resin composition containing an alkali-insoluble resin and an inorganic filler. The content of the inorganic filler in the resin composition is 50 to 80% by mass relative to 100% by mass of the nonvolatile content in the resin composition. In the case where the content of the inorganic filler is less than 50% by mass, the amount of the inorganic filler that can be dissolved by the etching solution is too small with respect to the entire resin composition, so etching will not proceed. If the content of the inorganic filler exceeds 80% by mass, since the fluidity of the resin composition is reduced, flexibility tends to be reduced, and practicality is poor.

In the present invention, examples of inorganic fillers include silicates such as silica, glass, clay, and mica; oxides such as aluminum oxide, magnesium oxide, titanium oxide, and silicon oxide; carbonates such as magnesium carbonate and calcium carbonate; and hydroxides. Hydroxides such as aluminum, magnesium hydroxide and calcium hydroxide; sulfates such as barium sulfate and calcium sulfate. Furthermore, the inorganic filler may further include aluminum borate, aluminum nitride, boron nitride, strontium titanate, barium titanate, and the like. Among these, since at least one compound selected from the group consisting of silica, glass, clay, and aluminum hydroxide is dissolved in an aqueous solution containing alkali metal hydroxide, it can be used more preferably. Silica is better due to its excellent low thermal expansion, especially spherical molten silica. The inorganic filler may be used alone or in combination of two or more.

The alkali-insoluble resin of the present invention will be described. The alkali-insoluble resin is not particularly limited except for the property of being insoluble in an alkaline aqueous solution. Specifically, it refers to a resin with a very small content of carboxyl group-containing resin required to dissolve in an alkaline aqueous solution. The acid value (JIS K2501: 2003) as an indicator of the content of free carboxyl groups in the resin is less than 40 mgKOH /g is better. More specifically, the alkali-insoluble resin is, for example, a resin containing an epoxy resin and a thermosetting agent that hardens the epoxy resin. Examples of alkaline aqueous solutions include: aqueous solutions containing inorganic alkaline compounds such as alkali metal silicates, alkali metal hydroxides, alkali metal phosphates, alkali metal carbonates, ammonium phosphates, and ammonium carbonates, as well as aqueous solutions containing monoethanolamine, diethanolamine, and triethanolamine. Ethanolamine, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, cyclohexylamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, 2 -Hydroxyethyl trimethylammonium hydroxide (choline) and other organic alkaline compounds in water.

Examples of the epoxy resin include bisphenol-type epoxy resins such as bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, and bisphenol S-type epoxy resin; phenol novolak-type epoxy resin, and cresol novolak. Novolac type epoxy resins such as type epoxy resins. In addition, the epoxy resin may further include biphenyl type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, phenoxy type epoxy resin, and sulphur type epoxy resin. The epoxy resin may be used alone or in combination of two or more.

系硬化劑、氰酸酯酯樹脂等。熱硬化劑可單獨使用此等當中的一種，亦可將兩種以上組合使用。 The thermosetting agent is not particularly limited as long as it has the function of hardening epoxy resin, but preferred ones include: phenolic hardener, naphthol hardener, active ester hardener, benzo

Series hardener, cyanate ester resin, etc. One of these thermosetting agents may be used alone, or two or more of them may be used in combination.

In addition to containing the above-mentioned hardener, it may further contain a hardening accelerator. Examples of the hardening accelerator include organic phosphine compounds, organic sulfonate compounds, imidazole compounds, amine addition compounds, and tertiary amine compounds. One of these hardening accelerators can be used alone, or two or more of them can be used in combination use. In addition, when a cyanate ester resin is used as the thermosetting agent, in order to shorten the curing time, an organometallic compound used as a curing catalyst may be added. Examples of the organic metal compound include organic copper compounds, organic zinc compounds, and organic cobalt compounds.

The resin composition containing alkali-insoluble resin and inorganic filler can be cured by heat to form an insulating resin composition layer. However, the etching in the etching method of the present invention is in the A stage (before the hardening reaction starts) or the B stage (the hardening reaction). In the middle stage). In the A stage or the B stage, the alkali-insoluble resin will not dissolve in the etching solution of the present invention, but a part or all of the inorganic filler is dissolved by the etching solution of the present invention, thereby dispersing and removing the resin composition. At stage C, when the resin is completely cured, the etching solution of the present invention is difficult to swell and penetrate the resin composition layer, and it becomes difficult to uniformly etch.

Regarding the thermal hardening conditions from the A stage to the B stage, it is preferably 100 to 160°C for 10 to 60 minutes, more preferably 100 to 130°C for 10 to 60 minutes, but it is not limited to this. If it is heated at a high temperature exceeding 160°C, thermal hardening proceeds further, and it becomes difficult to perform an etching treatment using the etching solution of the present invention.

The etching method of the present invention will be described below. FIG. 3 is a cross-sectional step diagram showing an example of the step of etching the resin composition layer 4 by the etching method of the present invention. In this etching method, a solder resist pattern can be formed by exposing part or all of the solder pad 3 on the circuit board from the resin composition layer 4.

In step (I), the copper foil 3'on the surface of the copper-clad laminate 1'composed of the insulating layer 2 and the copper foil 3'is patterned by etching, thereby forming a conductor pattern A, and the formation Circuit board 1 with solder pads 3.

In step (II), the resin composition layer 4 with copper foil 6 is formed on the surface of the circuit board 1 so as to cover the entire surface.

In step (III), the copper foil 6 on the resin composition layer 4 is patterned by etching to form a metal mask as the etching resist 5.

In step (IV), the resin composition layer 4 is etched with the etching solution for the resin composition layer through the etching resist 5 (metal mask) until a part or all of the bonding pad 3 is exposed.

In the step (V), the etching resist 5 (metal mask) is removed by etching to form a solder resist pattern in which part or all of the solder pad 3 is exposed from the resin composition layer 4.

In the etching method of the present invention, the temperature of the etching solution is preferably 60 to 90°C. Although the most suitable temperature varies depending on the type of resin composition, the thickness of the resin composition layer containing the resin composition, and the pattern shape obtained by the process of removing the resin composition, the etching solution The temperature is more preferably 60 to 85°C, and still more preferably 70 to 85°C.

In the etching treatment of the resin composition using the etching solution of the present invention, part or all of the highly filled inorganic filler is slowly dissolved from the surface layer of the resin composition and dispersed together with the alkali-insoluble resin. The resin composition is removed.

In the etching method of the present invention, in the treatment of etching the resin composition, methods such as immersion treatment, puddle treatment, spray treatment, brushing, and scrapping can be used. Among them, immersion treatment is particularly preferred.

In the etching method of the present invention, after the resin composition is removed by etching treatment, the etching solution remaining on the surface of the resin composition is washed by water washing treatment. In terms of the diffusion rate and the uniformity of solution supply, the method of water washing treatment is preferably a spray method. The washing water can be tap water, industrial water, pure water, etc. Among them, it is preferable to use pure water. Generally speaking, pure water Can be used for industrial purposes. Furthermore, the temperature of the washing water is equal to or lower than the temperature of the etching solution, and it is preferable that the temperature difference between the washing water and the etching solution is 40 to 50°C.

In the etching method of the present invention, it is preferable to have an ultrasonic irradiation step after the above-mentioned etching treatment step using an etching solution. The ultrasonic irradiation step may be performed in the water washing step subsequent to the etching treatment step, or may be performed in the water washing step after the etching treatment step and in the step of removing the etching resist 5 performed after the drying step. Moreover, ultrasonic irradiation can also effectively function in the water washing step after the etching resist 5 is removed. However, even if ultrasonic irradiation is performed during the etching process, the desired effect cannot be obtained. In the above steps (I) to (V), the etching method of the present invention refers to the next step from (III) to (V). In addition, the ultrasonic irradiation step of the present invention refers to the step of performing ultrasonic irradiation in a wet manner after the etching treatment by the etching solution in (IV) is completed until the next step is started until the end of (V).

Regarding the reason why the desired effect cannot be obtained even if ultrasonic irradiation is performed during the etching process, it is believed that it is related to the dissolution, dispersion and removal mechanism of the etching method of the present invention. The etching mechanism of the present invention is to dissolve part or all of the highly filled inorganic filler in the resin composition insoluble in the etching solution in the etching solution containing a high concentration of alkali metal hydroxide, so that the resin composition cannot be formed. An etching method that maintains the shape of the film and removes the part where the film cannot be formed in the subsequent steps. Therefore, the ultrasonic irradiation performed in the etching solution will cause the shape after the etching to be disordered, and the in-plane uniformity cannot be maintained, and the desired effect cannot be obtained.

Regarding the conditions of ultrasonic irradiation, although the composition and curing state of the resin composition containing the alkali-insoluble resin and 50 to 80% by mass of inorganic fillers, the composition of the etching solution, etc. are different, the frequency is preferred. It is 15 kHz or more, more preferably 50 kHz or more. The liquid temperature during ultrasonic irradiation is preferably 70°C or lower, more preferably 60°C or lower.

In the etching method of the present invention, it is preferable to perform the etching treatment using the etching solution of the present invention after the pretreatment is performed with the acidic aqueous solution containing 2.5 to 7.5% by mass of an anionic surfactant. That is, the etching method of the present invention preferably has the following step before the etching treatment step: the resin composition is pretreated with an acidic aqueous solution containing 2.5 to 7.5% by mass of an anionic surfactant.

The treatment liquid before the present invention is an acid aqueous solution containing 2.5 to 7.5% by mass of anionic surfactant. The anionic surfactant contained in the pretreatment liquid of the present invention may include: lauryl sulfate, polyethylene glycol lauryl ether sulfate, polyethylene glycol alkyl ether sulfate, polyalkylene glycol alkenyl ether sulfate, Alkylbenzene sulfonate, dodecylbenzene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, alkyl diphenyl ether disulfonate, alkane sulfonate, alkenyl succinic acid Salt etc. Among these anionic surfactants, especially because polyethylene glycol lauryl ether sulfate, polyethylene glycol alkyl ether sulfate, and alkyl naphthalene sulfonate are open in the resin composition layer In the small-diameter opening treatment in which the opening diameter of the portion becomes Φ100 μm or less, the occurrence of unetched areas is also suppressed, and therefore, it is preferable, and alkylnaphthalene sulfonate is particularly preferable. The relative ion is preferably alkali metal ions and alkanolamine salt ions. Moreover, these anionic surfactants may be used alone or in combination of two or more.

In the small-diameter opening treatment where the opening diameter of the opening in the resin composition layer is to be Φ100μm or less, in order to suppress the occurrence of unetched areas, the content of the anionic surfactant contained in the pretreatment liquid is preferably 2.5 mass % Or more is preferable, and 3 mass% or more is more preferable. Moreover, from the viewpoints that the obtained effect is not increased, the economic efficiency is poor, the water washing after the pretreatment takes time, and when the water washing is insufficient, there may be unetched areas due to the aggregation of the anionic surfactant. It is preferably 7.5 mass% or less, and more preferably 6 mass% or less.

The pretreatment solution of the present invention is acidic. Even in the small-diameter opening treatment where the opening diameter of the opening in the resin composition layer is to be reduced to Φ100μm or less, from the viewpoint of suppressing the occurrence of unetched areas, the pH is set to 6 or less Better. In addition, from the viewpoints that the obtained effect is not increased, the economic efficiency is poor, and the mixing of the pH adjuster takes time, the pH is preferably 1 or more. As the pH adjuster, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, hydroxide salt, carbonate, etc. can be used. Furthermore, the pretreatment liquid of the present invention may also contain well-known additives such as defoamers, foam inhibitors, thickeners, and preservatives.

Tap water, industrial water, pure water, etc. can be used as the water system used for the treatment liquid before the present invention. Among them, it is preferable to use pure water. In the present invention, pure water generally used for industrial purposes can be used.

In the present invention, the pretreatment time is not particularly limited. However, in the small-diameter opening treatment where the opening diameter of the opening in the resin composition layer is to be less than Φ100μm, in order to suppress the occurrence of unetched areas, the pretreatment time is 1 minute or more is preferable, and 3 minutes or more is more preferable. The pretreatment time is preferably 10 minutes or less. The temperature of the treatment solution prior to the present invention is not particularly limited, but in the small-diameter opening treatment where the opening diameter of the opening in the resin composition layer is to be Φ100μm or less, in order to suppress the occurrence of unetched areas, the temperature is 10°C or more It is preferred, and more preferably 30°C or higher. The temperature of the pretreatment liquid is preferably 70°C or lower.

After step (III), in step (IV), the pretreatment liquid is brought into contact with the resin composition layer 4 and the etching resist 5 to increase the affinity between the etching liquid and the resin composition layer 4, and then the etching For the resist 5, the resin composition layer 4 is etched by the etching solution of the present invention until a part or all of the bonding pad 3 is exposed.

After the pretreatment liquid is brought into contact with the resin composition layer 4 and the etching resist 5, the pretreatment liquid adhering to the surface of the resin composition layer 4 is preferably washed by a water washing treatment. In terms of the diffusion rate and the uniformity of solution supply, the method of water washing treatment is preferably spray. Washing water can make Use tap water, industrial water, pure water, etc. Among them, it is preferable to use pure water. The pure water system can be used generally for industrial purposes. Moreover, the temperature of the washing water is preferably 10 to 30°C.

In the etching process step, when the etching resist 5 is used, in addition to the above-mentioned metal mask, the etching resist 5 can also use a dry film photoresist pattern.

The dry film photoresist of the present invention contains at least a photocrosslinkable resin composition, which is formed by coating a photocrosslinkable resin on a carrier film such as polyester to form a photocrosslinkable resin layer, and optionally poly A protective film such as ethylene is coated on the photo-crosslinkable resin layer. The photocrosslinkable resin layer contains, for example, a carboxyl group-containing binder polymer, a photopolymerizable compound having at least one polymerizable ethylenic unsaturated group in the molecule, a photopolymerization initiator, a solvent, and other additives. These blending ratios are determined by the balance of required properties such as sensitivity, resolution, and degree of crosslinking. Examples of photocrosslinkable resin compositions are described in "Photopolymer Handbook" (Edited by Photopolymer Forum, published in 1989, Journal of Industrial Research Co., Ltd.) and "Photopolymer/Technology" (Yao Yamamoto, Edited by Motota Nagamatsu, published in 1988, Nikkan Kogyo Shimbun, etc., desired photocrosslinkable resin compositions can be used. The thickness of the photo-crosslinkable resin layer is preferably 15 to 100 μm, more preferably 20 to 50 μm.

The exposure method of the dry film photoresist of the present invention can include: reflection image exposure using xenon lamp, high pressure mercury lamp, low pressure mercury lamp, ultra high pressure mercury lamp, UV fluorescent lamp as the light source; single-side contact exposure and double-side contact using photomask Type exposure; and proximity exposure, projection exposure and laser scanning exposure. For scanning exposure, He-Ne laser, He-Cd laser, argon laser, krypton ion laser, ruby laser, YAG laser, nitrogen laser, pigment laser, excimer can be used Laser light sources such as lasers convert the SHG (second harmonic generation) wavelength to perform scanning exposure according to the emission wavelength, or can be achieved by scanning exposure by using liquid-crystal shutter or micromirror array shutter Make an exposure.

The dry film photoresist development method of the present invention uses a developer suitable for the photo-crosslinkable resin layer to be used, and sprays from the vertical direction of the substrate to the surface of the substrate to remove unnecessary dry film photoresist (unexposed part) , And an etching resist 5 composed of a dry film photoresist pattern is formed. In general, the developer uses 1 to 3% by mass of sodium carbonate aqueous solution, and more preferably uses 1% by mass of sodium carbonate aqueous solution.

As for the peeling method of the dry film photoresist pattern used as the etching resist 5, a peeling solution suitable for the photo-crosslinkable resin layer used is used, and sprayed from the vertical direction of the substrate to the surface of the substrate to remove the dry film Photoresist pattern. Generally speaking, a 2 to 4% by mass aqueous sodium hydroxide solution is used for the peeling liquid, and a 3% by mass aqueous sodium hydroxide solution is more preferable.

(Example)

Hereinafter, the present invention will be further described in detail with examples, but the present invention is not limited to these examples.

(Examples 1-1 to 1-15, 1-17, Comparative Examples 1-2 to 1-7)

Add 78% by mass of spherical molten silica as an inorganic filler, 10% by mass of biphenyl aralkyl type epoxy resin as epoxy resin, and 10% by mass of phenol novolak type cyanate resin as a thermosetting agent, 1% by mass of triphenylphosphine as a hardening accelerator, a coupling agent and a leveling agent so that the total amount becomes 100% by mass, and then the resultant is mixed with methyl ethyl ketone and cyclohexanone as a medium. A liquid resin composition was obtained.

Then, after coating the liquid resin composition on a polyethylene terephthalate film (thickness 38 μm), it was dried at 100° C. for 5 minutes to remove the medium. Thereby, an A-stage resin composition layer composed of a resin composition containing an alkali-insoluble resin and an inorganic filler with a film thickness of 20 μm was formed.

Next, a copper foil 6 having a thickness of 3 μm, a peeling layer, and a metal foil capable of being peeled from the carrier foil are prepared in this order, and the copper foil 6 and the above-mentioned resin composition layer 4 are thermally pressed together so that the copper foil 6 is in contact with the resin composition layer 4 , The peeling layer and carrier foil were peeled, and the resin composition layer 4 with copper foil 6 was obtained.

The copper foil 3'on one surface of the epoxy resin glass cloth substrate copper-clad laminate 1'(area 170mm×255mm, copper foil thickness 12μm, substrate thickness 0.1mm) is patterned by etching to obtain the The epoxy resin glass cloth substrate of the conductor pattern A (circuit board 1). Then, the polyethylene terephthalate film was peeled off from the resin composition layer 4 with the copper foil 6, and a vacuum heating and pressing laminator was used to vacuum heat and press at a temperature of 100°C and a pressure of 1.0 MPa to form After the epoxy resin glass cloth substrate with the conductive pattern A is formed, it is heated at 130° C. for 45 minutes to form the B-stage resin composition layer 4.

Then, the copper foil 6 on the resin composition layer 4 is patterned by etching, openings are formed in a predetermined area of the copper foil, and the resin composition layer 4 with an etching resist 5 (metal mask) is prepared.

Then, the resin composition layer 4 was immersed in the etching solution described in Table 1 or Table 2 at 80° C. via the etching resist 5 to perform the etching treatment. After the etching treatment, the etching solution remaining on the surface of the resin composition layer 4 is cleaned by spraying treatment with pure water.

In terms of the etching solution treatment time, the opening length a of the etching resist 5, the film thickness b of the resin composition layer 4, and the resin composition described in Figure 3 (III) and (V) The processing time when the bottom length c of the opening of the layer 4 becomes a+2b=c is referred to as the "standard processing time". Specifically, since the opening length a of the etching resist 5 is 270 μm, and the film thickness b of the resin composition layer 4 is 20 μm, the bottom length c of the opening of the resin composition layer 4 will be 310 μm ± 5 μm. The time is set as "standard processing time" and is shown in Table 1 and Table 2.

In the opening of the etching resist 5, whether the resin composition layer 4 can be reliably removed is evaluated for "the presence or absence of residual resin". Moreover, as to whether the resin composition layer 4 can be stably removed, the third figure (V) The residue recorded in the evaluation part 7 is evaluated and used as the "processing margin". Furthermore, the "presence of solder erosion" was evaluated as the deformation evaluation of the opening shape of the resin composition layer 4. The results are shown in Table 1 and Table 2. The criteria for each evaluation are as follows.

(With or without residual resin)

○: No resin composition remains.

△: Although a very small amount of resin composition remains, it is to the extent that it can be easily removed by post-treatment such as plasma cleaning treatment.

×: A lot of resin composition remains, and it is to the extent that it cannot be removed by post-treatment.

(Processing margin)

○: Even if the etching treatment time is "standard treatment time ±30%", no resin composition remains on the surface after etching.

△: Even if the etching treatment time is "standard treatment time ±30%", a very small amount of resin composition remains on the surface after etching, but it is to the extent that it can be easily removed by post-treatment such as plasma cleaning treatment.

×: The etching treatment time is "standard treatment time ±30%", and a large amount of resin composition remains on the surface after etching, which cannot be removed by post-treatment.

(With or without welding corrosion)

○: No welding corrosion is observed in the resin composition layer.

△: Small welding corrosion is observed on the bottom surface of the resin composition layer.

×: Welding corrosion which is a practical problem is observed on the bottom surface of the resin composition layer.

(Example 1-16)

Except that the content of the spherical molten silica was set to 55% by mass and the content of the biphenyl aralkyl type epoxy resin was set to 33% by mass, the etching treatment was performed in the same manner as in Example 1-3. The results are shown in Table 2.

(Comparative Example 1-1)

Except that the content of the spherical molten silica was set to 45% by mass and the content of the biphenyl aralkyl type epoxy resin was set to 43% by mass, the etching treatment was performed in the same manner as in Example 1-3. Although the etching time was extended to 30 minutes, a large amount of resin remained on the surface of the conductor pattern and the epoxy resin glass cloth substrate, and the resin composition layer could not be etched. The results are shown in Table 2.

(Comparative example 1-8)

After the resin composition layer 4 with the etching resist 5 obtained by the same method as in Example 1-1 was subjected to an etching process by wet sandblasting, the etching resist 5 was removed. Observation of the resultant with an optical microscope revealed that the etching amount in the resin composition layer 4 was not uniform, and there were places where the resin composition remained on the epoxy resin glass cloth substrate. In addition, many scratches caused by sandblasting can be confirmed in the conductor pattern exposed on a part or all of the surface.

[Table 1]

[Table 2]

From the results of Table 1 and Table 2, it can be judged that compared with the comparative example, the etching solution of the present invention produces less welding corrosion, and the residue of the resin composition is less, and the resin containing alkali-insoluble resin and inorganic filler can be reduced The composition is removed stably.

(Examples 2-1 to 2-12, 2-14, Comparative Examples 2-2 to 2-8)

Except for using the etching solutions described in Table 3 or Table 4, the etching treatment was performed in the same manner as in Example 1-1. The results are shown in Table 3 and Table 4.

(Example 2-13)

Except that the content of the spherical molten silica was set to 55% by mass and the content of the biphenyl aralkyl type epoxy resin was set to 33% by mass, the etching treatment was performed in the same manner as in Example 2-3. The results are shown in Table 4.

(Comparative Example 2-1)

Except that the content of spherical molten silica is set to 45% by mass, the content of biphenyl aralkyl type epoxy resin is set to 43% by mass, and the etching time is extended to 30 minutes, the same as in Example 2-3 Method of etching treatment. Although the etching time was extended to 30 minutes, a large amount of resin remained on the surface of the conductor pattern and the epoxy resin glass cloth substrate, and the resin composition layer could not be etched. The results are shown in Table 4.

[table 3]

[Table 4]

From the results of Table 3 and Table 4, it can be judged that, compared with the comparative example, the etching solution of the present invention produces less welding corrosion, and the residue of the resin composition is less, and the resin containing alkali-insoluble resin and inorganic filler can be reduced The composition is removed stably.

(Examples 3-1 to 3-12, 3-14, Comparative Examples 3-2 to 3-8)

Except for using the etching solutions described in Table 5 or Table 6, the etching treatment was performed in the same manner as in Example 1-1. The results are shown in Table 5 and Table 6.

(Example 3-13)

Except that the content of spherical molten silica was set to 55% by mass and the content of biphenyl aralkyl type epoxy resin was set to 33% by mass, the etching treatment was performed in the same manner as in Example 3-3. The results are shown in Table 6.

(Comparative Example 3-1)

Except that the content of spherical molten silica is set to 45% by mass, the content of biphenyl aralkyl type epoxy resin is set to 43% by mass, and the etching time is extended to 30 minutes, the same as in Example 3- 3 same party Method for etching treatment. Although the etching time was extended to 30 minutes, a large amount of resin remained on the surface of the conductor pattern and the epoxy resin glass cloth substrate, and the resin composition layer could not be etched. The results are shown in Table 6.

[table 5]

[Table 6]

From the results of Table 5 and Table 6, it can be judged that, compared with the comparative example, the etching solution of the present invention produces less welding corrosion, and the residue of the resin composition is less, and the resin containing alkali-insoluble resin and inorganic filler can be reduced The composition is removed stably.

(Examples 4-1 to 4-7, Comparative Examples 4-2 to 4-3)

Add 78% by mass of spherical molten silica as an inorganic filler, 10% by mass of biphenyl aralkyl type epoxy resin as epoxy resin, and 10% by mass of phenol novolak type cyanate resin as a thermosetting agent, 1% by mass of triphenylphosphine as a hardening accelerator, a coupling agent and a leveling agent so that the total amount becomes 100% by mass, and then the resultant is mixed with methyl ethyl ketone and cyclohexanone as a medium. A liquid resin composition was obtained.

Then, after coating the liquid resin composition on a polyethylene terephthalate film (thickness 38 μm), it was dried at 100° C. for 5 minutes to remove the medium. Thereby, an A-stage resin composition layer composed of a resin composition containing an alkali-insoluble resin and an inorganic filler with a film thickness of 20 μm was formed.

Next, a copper foil 6 with a thickness of 3 μm, a peeling layer, and a metal foil peelable from the carrier foil are prepared in this order, and the two are thermally pressed so that the copper foil and the resin composition layer are in contact with each other. The peeling layer and carrier foil were peeled, and the resin composition layer 4 with copper foil 6 was obtained.

The copper foil 3'on one surface of the epoxy resin glass cloth substrate copper-clad laminate 1'(area width 400mm×500mm, copper foil thickness 12μm, substrate thickness 0.1mm) is patterned by etching to obtain The epoxy resin glass cloth substrate (circuit board 1) on which the conductor pattern A was formed was evenly arranged in the plane with 10 in the horizontal direction and 12 in the vertical direction. Then, the polyethylene terephthalate film was peeled off from the resin composition layer 4 with the copper foil 6, and a vacuum heating and pressing laminator was used to vacuum heat and press at a temperature of 100°C and a pressure of 1.0 MPa to form After the epoxy resin glass cloth substrate with the conductive pattern A is formed, it is heated at 130° C. for 45 minutes to form the B-stage resin composition layer 4.

Then, the copper foil 6 on the resin composition layer 4 is patterned by etching, openings are formed in a predetermined area of the copper foil, and the resin composition layer 4 with an etching resist 5 (metal mask) is prepared.

Then, the resin composition layer 4 was immersed at 80°C with the etching solution described in Table 7 through the etching resist 5, and then in order to remove the resin composition layer 4 in a tank filled with 25°C tap water Perform impregnation treatment. When performing the immersion treatment with the tap water, the presence or absence of ultrasonic irradiation is changed. After that, the surface is cleaned by spraying with pure water. Table 7 shows the composition of the etching solution and the presence or absence of ultrasonic irradiation.

In the opening of the etching resist 5, whether the resin composition layer 4 can be reliably removed is used to evaluate "the presence or absence of residual resin". Furthermore, "welding erosion" was evaluated as a deformation evaluation of the opening shape of the resin composition layer 4. In addition, the target opening diameter (target opening diameter) is the same. Observe the opening d at 120 locations in the plane, and set the opening diameter of the opening with the largest opening diameter as the "maximum" and the smallest opening diameter The diameter of the opening is set to the "minimum", and "(maximum-minimum) / Target value × 100" to obtain the variation value (%), and evaluate the "in-plane uniformity". The results are shown in Table 7. The criteria for each evaluation are as follows.

(With or without residual resin)

○: No resin composition remains.

○△: Although a very small amount of resin composition remains, it is to the extent that it does not cause problems.

△: Although a small amount of resin composition remains, it is to the extent that it can be easily removed by a plasma cleaning treatment.

×: A lot of resin composition remains, and it is to the extent that it cannot be removed by the plasma cleaning treatment.

(Welding corrosion)

○: No welding corrosion is observed in the resin composition layer.

○△: Very little welding corrosion is observed on the bottom surface of the resin composition layer.

△: Although small welding corrosion is observed on the bottom surface of the resin composition layer, it is to the extent that it does not cause a problem.

×: Welding corrosion which is a practical problem is observed on the bottom surface of the resin composition layer.

(In-plane uniformity)

○: The uniformity is very high, and the variation value is less than 3%.

○△: The uniformity is high, and the variation value is 3% or more and less than 5%.

△: Uniform, with a variation value of 5% or more and less than 6%.

×: It cannot be said to be uniform, and the variation value is 6% or more.

(Example 4-8)

The etching treatment was performed in the same manner as in Example 4-2 except that the content of the spherical molten silica was set to 55% by mass and the content of the biphenyl aralkyl type epoxy resin was set to 33% by mass. The results are shown in Table 7.

(Comparative Example 4-1)

Except that the content of the spherical molten silica was set to 45% by mass and the content of the biphenyl aralkyl type epoxy resin was set to 43% by mass, the etching treatment was performed in the same manner as in Example 4-2. Although the etching time was extended to 30 minutes, a large amount of resin remained on the surface of the conductor pattern and the epoxy resin glass cloth substrate, and the resin composition layer could not be etched. The results are shown in Table 7.

(Examples 4-9 to 4-13)

The etching was performed in the same manner as in Examples 4-1, 4-2, 4-4, 4-6, and 4-7, except that ultrasonic irradiation was not performed during the immersion treatment to remove the resin composition layer 4 deal with. The results are shown in Table 7.

(Example 4-14)

The etching resist 5 (metal mask) of (IV) after the etching treatment obtained by the same method as in Example 4-10 was removed using a ferric chloride solution, and ultrasonic waves were irradiated in the subsequent washing step. The results are shown in Table 7.

[Table 7]

From the results in Table 7, it can be judged that by having an ultrasonic irradiation step after the etching treatment step using the etching solution of the resin composition, the resin composition containing the alkali-insoluble resin and the inorganic filler can be less welded. And the resin composition can be removed stably without residue. Furthermore, it is judged that the uniformity within the surface is also high.

(Examples 5-1 to 5-7, Comparative Examples 5-2 to 5-3)

Except for using the etching solutions described in Table 8 or Table 9, the etching treatment was performed in the same manner as in Example 4-1. The results are shown in Table 8 and Table 9.

(Example 5-8)

Except that the content of spherical molten silica is set to 55% by mass, the content of biphenyl aralkyl type epoxy resin is set to 33% by mass, and the etching solution described in Table 9 is used, the same as in Example 4 -1 Perform the etching treatment in the same way. The results are shown in Table 9.

(Comparative Example 5-1)

Except that the content of the spherical molten silica was set to 45% by mass and the content of the biphenyl aralkyl type epoxy resin was set to 43% by mass, the etching treatment was performed in the same manner as in Example 5-8. Although the etching time was extended to 30 minutes, a large amount of resin remained on the surface of the conductor pattern and the epoxy resin glass cloth substrate, and the resin composition layer could not be etched. The results are shown in Table 9.

(Examples 5-9 to 5-13)

Except that ultrasonic irradiation was not carried out during the immersion treatment to remove the resin composition layer 4, it was carried out in the same manner as in Examples 5-1, 5-3, 5-4, 5-5, and 5-7. Etching treatment. The results are shown in Table 9.

(Example 5-14)

After the etching process was performed in the same manner as in Examples 5-12, the etching resist 5 (metal mask) was removed with a ferric chloride solution, and ultrasonic waves were irradiated in the subsequent washing step. The results are shown in Table 9.

[Table 8]

[Table 9]

From the results of Table 8 and Table 9, it can be judged that by having an ultrasonic irradiation step after the etching treatment step using the etching solution of the resin composition, the resin composition containing the alkali-insoluble resin and the inorganic filler can be less produced Welding corrosion, and the resin composition can be removed stably without residue. Furthermore, it is judged that the uniformity within the surface is also high.

(Examples 6-1 to 6-11, Comparative Examples 6-2 to 6-7)

Except for using the etching solutions described in Table 10 or Table 11, the etching treatment was performed in the same manner as in Example 4-1. The results are shown in Table 10 and Table 11.

(Example 6-12)

Except that the content of spherical molten silica was set to 55% by mass and the content of biphenyl aralkyl type epoxy resin was set to 33% by mass, the etching treatment was performed in the same manner as in Example 6-3. The results are shown in Table 11.

(Comparative Example 6-1)

Except that the content of spherical molten silica was set to 45% by mass and the content of biphenyl aralkyl type epoxy resin was set to 43% by mass, the etching treatment was performed in the same manner as in Example 6-3. Although the etching time was extended to 30 minutes, a large amount of resin remained on the surface of the conductor pattern and the epoxy resin glass cloth substrate, and the resin composition layer could not be etched. The results are shown in Table 11.

(Examples 6-13 to 6-20)

The etching treatment was performed in the same manner as in Examples 6-1 to 6-8, except that ultrasonic irradiation was not performed during the immersion treatment for removing the resin composition layer 4.

(Example 6-21)

After the etching process was performed in the same method as in Examples 6-15, the etching resist 5 (metal mask) was removed using a ferric chloride solution, and ultrasonic waves were irradiated in the subsequent washing step. The results are shown in Table 11.

[Table 10]

[Table 11]

From the results in Table 10 and Table 11, it can be judged that by having an ultrasonic irradiation step after the etching treatment step using the etching solution of the resin composition, the resin composition containing alkali-insoluble resin and inorganic filler can be less produced Welding corrosion, and the resin composition can be removed stably without residue. Furthermore, it is judged that the uniformity within the surface is also high.

(Etching method with pre-processing steps)

Added 78% by mass of spherical molten silica as an inorganic filler, 10% by mass of biphenyl aralkyl type epoxy resin as epoxy resin, and 10% by mass of phenol novolak type cyanate resin as a thermosetting agent %, 1% by mass of triphenylphosphine as a hardening accelerator, and a coupling agent and a leveling agent to make the total amount 100% by mass, and then combine the resultant with methyl ethyl ketone and cyclohexanone as a medium Mix to obtain a liquid resin composition.

Then, after coating the liquid resin composition on a polyethylene terephthalate film (thickness 38 μm), it was dried at 100° C. for 5 minutes to remove the medium. Thereby, an A-stage resin composition layer composed of a resin composition containing an alkali-insoluble resin and an inorganic filler with a film thickness of 20 μm was formed.

Next, a copper foil 6 with a thickness of 3 μm, a peeling layer, and a metal foil peelable from the carrier foil are prepared in this order, and the two are thermally pressed so that the copper foil and the resin composition layer are in contact with each other. The peeling layer and carrier foil were peeled, and the resin composition layer 4 with copper foil 6 was obtained.

The copper foil 3'on one surface of the epoxy resin glass cloth substrate copper-clad laminate 1'(area 170mm×255mm, copper foil thickness 12μm, substrate thickness 0.1mm) is patterned by etching to obtain the The epoxy resin glass cloth substrate of the conductor pattern A (circuit board 1). Then, the polyethylene terephthalate film was peeled off from the resin composition layer 4 with the copper foil 6, and a vacuum heating and pressing laminator was used to vacuum heat and press at a temperature of 100°C and a pressure of 1.0 MPa to form After the epoxy resin glass cloth substrate with the conductive pattern A is formed, it is heated at 130° C. for 45 minutes to form the B-stage resin composition layer 4.

Then, the copper foil 6 on the resin composition layer 4 is patterned by etching, and openings are formed in a predetermined area of the copper foil 6 to prepare a resin composition layer 4 with an etching resist 5 (metal mask).

After contacting the resin composition layer 4 and the etching resist 5 with the pretreatment liquid (30°C) described in Table 12 by immersion treatment for 5 minutes, a spray-washing treatment with pure water for 1 minute was carried out to raise the etching liquid After the affinity with the resin composition layer 4, the resin composition layer 4 was immersed in the etching solution described in Table 13 at 80° C. through the etching resist 5 to perform the etching treatment. In addition, the pH of each pretreatment liquid is such that Adjust with sulfuric acid or potassium hydroxide. After the etching treatment, the etching liquid remaining on the surface of the resin composition layer 4 is washed by spray treatment with pure water.

A process in which the opening length a of the etching resist 5 described in Figure 3, the film thickness b of the resin composition layer 4, and the bottom length c of the opening of the resin composition layer 4 become a+2b=c. Set the time as "standard processing time". Specifically, since the opening length a of the etching resist 5 is 160 μm and the film thickness b of the resin composition layer 4 is 20 μm, the bottom length c of the opening of the resin composition layer 4 will be 200 μm ± 5 μm. Set the time as "standard processing time".

[Table 12]

[Table 13]

Confirm that when the opening length a of the etching resist 5 is 50 μm and the film thickness b of the resin composition layer 4 is 20 μm, the opening 100 of the etching resist 5 is determined to be the length of the bottom of the opening of the resin composition layer 4 When c is 90μm±5μm, whether the small diameter opening treatment has been completed is used to evaluate the "small diameter opening". The results are shown in Table 14.

(Small diameter opening)

○: Under the standard processing time, there are 95 or more resin openings among the 100 small-diameter openings.

△: Under the standard processing time, the resin openings in the 100 small-diameter openings are 85 or more and less than 95.

×: Under the standard processing time, the number of resin openings among the 100 small-diameter openings is less than 85.

[Table 14]

From the results in Table 14, it can be judged that after the pretreatment is performed with the pretreatment solution composed of an acidic aqueous solution containing 2.5 to 7.5% by mass of an anionic surfactant, the etching solution of the resin composition is used for the etching treatment, thereby Even in the small-diameter opening treatment in which the opening diameter of the opening in the resin composition layer containing the alkali-insoluble resin and the inorganic filler is Φ100 μm or less, it is possible to suppress the unetched portion and perform the etching treatment.

(Examples 7-1 to 7-15, 7-17, Comparative Examples 7-2 to 7-7)

Added 78% by mass of spherical molten silica as an inorganic filler, 10% by mass of biphenyl aralkyl type epoxy resin as epoxy resin, and 10% by mass of phenol novolak type cyanate resin as a thermosetting agent , 1% by mass of triphenylphosphine as a hardening accelerator, and a coupling agent and a leveling agent to make the total amount 100% by mass, and then mix the obtained with methyl ethyl ketone and cyclohexanone as a medium , And a liquid resin composition is obtained.

Then, after coating the liquid resin composition on a polyethylene terephthalate film (thickness 38 μm), it was dried at 100° C. for 5 minutes to remove the medium. Thereby, an A-stage resin composition layer composed of a resin composition containing an alkali-insoluble resin and an inorganic filler with a film thickness of 20 μm was formed.

The copper foil 3'on one surface of the epoxy resin glass cloth substrate copper-clad laminate 1'(area 170mm×255mm, copper foil thickness 12μm, substrate thickness 0.1mm) is patterned by etching to obtain the The epoxy resin glass cloth substrate of the conductor pattern A (circuit board 1). Next, the resin composition layer 4 was vacuum thermocompressed on the epoxy resin glass cloth substrate on which the conductor pattern A was formed at a temperature of 100°C and a pressure of 1.0 MPa using a vacuum heating and compression laminator, and then heated at 130°C For 45 minutes, the B-stage resin composition layer 4 was formed.

Then, a dry film photoresist 6 (manufactured by Asahi Kasei Co., Ltd., trade name: ASG-302) was thermally pressed onto the resin composition layer 4, and then a contact exposure machine was used to apply an energy of 50 mJ/cm ² through a photomask. The dry film photoresist 6 is subjected to pattern exposure, and subsequently developed with a 1% by mass sodium carbonate aqueous solution at 25°C, whereby openings are formed in the predetermined area of the dry film photoresist 6 to prepare an etching resist 5 (dry film light Resistant pattern) of the resin composition layer 4.

Then, the resin composition layer 4 was immersed in the etching solution described in Table 15 at 80° C. via the etching resist 5 to perform the etching treatment. After the etching treatment, the etching solution remaining on the surface of the resin composition layer 4 is cleaned by spraying treatment with pure water. In terms of the etching solution treatment time, the opening length a of the etching resist 5, the film thickness b of the resin composition layer 4, and the resin composition layer described in Figure 3 (III) and (V) The processing time when the bottom length c of the opening of 4 becomes a+2b=c is referred to as the "standard processing time". Specifically, since the opening length a of the etching resist 5 is 270 μm, and the film thickness b of the resin composition layer 4 is 20 μm, the bottom length c of the opening of the resin composition layer 4 will be 310 μm ± 5 μm. The time is set as "standard processing time" and is shown in Table 15 and Table 16.

In the opening of the etching resist 5, the "resin remaining" is evaluated based on whether the resin composition layer 4 can be reliably removed. Moreover, whether the resin composition layer 4 can be stably removed is evaluated by the residue of the evaluation part 7 described in Fig. 3 (V), and this is regarded as the "processing margin". Furthermore, the "presence of solder erosion" was evaluated as the deformation evaluation of the opening shape of the resin composition layer 4. The results are shown in Table 15 and Table 16. The criteria for each evaluation are as follows.

(With or without residual resin)

○: No resin composition remains.

△: Although a very small amount of resin composition remains, it is to the extent that it can be easily removed by post-treatment such as plasma cleaning treatment.

×: A lot of resin composition remains, and it is to the extent that it cannot be removed by post-treatment.

(Processing margin)

○: Even if the etching treatment time is "standard treatment time ±30%", no resin composition remains on the surface after etching.

△: Even if the etching treatment time is "standard treatment time ±30%", a very small amount of resin composition remains on the surface after etching, but it is to the extent that it can be easily removed by post-treatment such as plasma cleaning treatment.

×: The etching treatment time is "standard treatment time ±30%", and a large amount of resin composition remains on the surface after etching, which cannot be removed by post-treatment.

(With or without welding corrosion)

○: No welding corrosion is observed in the resin composition layer.

△: Small welding corrosion is observed on the bottom surface of the resin composition layer.

×: Welding corrosion which is a practical problem is observed on the bottom surface of the resin composition layer.

(Example 7-16)

The etching treatment was performed in the same manner as in Example 7-3 except that the content of spherical molten silica was set to 55% by mass and the content of biphenyl aralkyl type epoxy resin was set to 33% by mass. The results are shown in Table 16.

(Comparative Example 7-1)

Except that the content of spherical molten silica is set to 45% by mass, the content of biphenyl aralkyl type epoxy resin is set to 43% by mass, and the etching time is extended to 30 minutes, the same as in Example 7- 3 Perform etching treatment in the same way. Although the etching time has been extended to 30 minutes, a large amount of resin remains on the surface of the conductor pattern and on the epoxy resin glass cloth substrate, and the resin composition layer cannot be etched. The results are shown in Table 16.

(Comparative Example 7-8)

The resin composition layer 4 with the etching resist 5 (dry film photoresist pattern) obtained by the same method as in Example 7-1 was etched by wet sandblasting, and then the etching resist 5 was removed. Observation of the resultant with an optical microscope revealed that the etching amount of the resin composition layer 4 was not uniform, and there were places where the resin composition remained on the epoxy resin glass cloth substrate. In addition, many scratches caused by sandblasting can be confirmed in the wet type of a part or all of the conductor pattern exposed on the surface.

[Table 15]

[Table 16]

From the results of Tables 15 and 16, it can be judged that compared to the comparative example, the resin composition of the present invention containing alkali-insoluble resin and inorganic filler produces less welding corrosion, and the resin composition can be free of residue and stable Remove.

(Examples 8-1 to 8-12, 8-14, Comparative Examples 8-2 to 8-8)

Except for using the etching solutions described in Table 17 or Table 18, the etching treatment was performed in the same manner as in Example 7-1. The results are shown in Table 17 and Table 18.

(Example 8-13)

Except that the content of spherical molten silica was set to 55% by mass and the content of biphenyl aralkyl type epoxy resin was set to 33% by mass, the etching treatment was performed in the same manner as in Example 8-3. The results are shown in Table 18.

(Comparative Example 8-1)

Except that the content of spherical molten silica is set to 45% by mass, the content of biphenyl aralkyl type epoxy resin is set to 43% by mass, and the etching time is extended to 30 minutes, the same as in Example 8- 3 The etching process was performed in the same way. Although the etching time was extended to 30 minutes, a large amount of resin remained on the surface of the conductor pattern and on the epoxy glass cloth substrate, and the resin composition layer could not be etched. The results are shown in Table 18.

[Table 17]

[Table 18]

From the results of Tables 17 and 18, it can be judged that, compared with the comparative example, the resin composition of the present invention containing alkali-insoluble resin and inorganic filler produces less welding corrosion, and the resin composition has less residue and can be stably To remove.

(Examples 9-1 to 9-12, 9-14, Comparative Examples 9-2 to 9-8)

Except for using the etching solutions described in Table 19 or Table 20, the etching treatment was performed in the same manner as in Example 7-1. The results are shown in Table 19 and Table 20.

(Example 9-13)

The etching treatment was performed in the same manner as in Example 9-3, except that the content of the spherical molten silica was 55% by mass and the content of the biphenyl aralkyl epoxy resin was 33% by mass. The results are shown in Table 20.

(Comparative Example 9-1)

Except that the content of spherical molten silica was set to 45% by mass, the content of biphenyl aralkyl type epoxy resin was set to 43% by mass, and the etching time was extended to 30 minutes, the same as in Example 9- 3 same Method of etching treatment. Although the etching time was extended to 30 minutes, a large amount of resin remained on the surface of the conductor pattern and the epoxy resin glass cloth substrate, and the resin composition layer could not be etched. The results are shown in Table 20.

[Table 19]

[Table 20]

From the results of Tables 19 and 20, it can be judged that compared to the comparative example, the resin composition of the present invention containing alkali-insoluble resin and inorganic filler produces less welding corrosion, and the resin composition can be free of residue and stable To remove.

(Industrial availability)

The etching solution and etching method of the present invention can be applied to an insulating resin composition layer filled with a high content of inorganic filler and excellent in heat resistance, dielectric properties, mechanical strength, chemical resistance, etc. Microfabrication of insulating resins such as multilayer build-up wiring boards, component built-in module substrates, flip-chip packaging substrates, and packaging substrate mounting mother boards.

Claims (11)

An etching solution for a resin composition, the resin composition containing an alkali-insoluble resin and 50 to 80% by mass of an inorganic filler, the etching solution contains 15 to 45% by mass of alkali metal hydroxide as the first component, and The second component is 1 to 40% by mass of ethanolamine compound, and contains 3 to 60% by mass of polyol compound, 2 to 20% by mass of polycarboxylic acid, or 2 to 20% by mass of hydroxy acid as the third component. The resin composition etching solution described in the first item of the scope of patent application, wherein the third component is 3 to 60% by mass of a polyol compound. The resin composition etching liquid described in the first or second patent application, wherein the molecular weight of the polyol compound is 80 or more and 200 or less. The etching solution of the resin composition according to any one of items 1 to 3 of the scope of patent application, wherein the polyol compound has 3 or more hydroxyl groups. The etching solution of the resin composition according to any one of items 1 to 4 of the scope of patent application, wherein the polyol compound is glycerin. The resin composition etching solution described in the first item of the scope of patent application, wherein the third component is 2 to 20% by mass of polycarboxylic acid. The etching solution of the resin composition described in the first item of the scope of the patent application, wherein the third component is 2 to 20% by mass of hydroxy acid. An etching method for a resin composition has the following steps: using the etching solution of the resin composition described in any one of items 1 to 7 of the scope of the patent application, for the etching solution containing alkali-insoluble resin and 50 to 80% by mass The resin composition of the inorganic filler is etched. The etching method of the resin composition as described in item 8 of the scope of patent application has an ultrasonic irradiation step after the etching treatment step. For example, the etching method of the resin composition described in item 8 or 9 of the scope of patent application, before the etching treatment step, further has a pretreatment step by a pretreatment liquid, the pretreatment liquid contains 2.5 to An acidic aqueous solution of 7.5 mass% anionic surfactant. The method for etching a resin composition according to any one of items 8 to 10 of the scope of patent application, wherein an etching resist is used in the etching treatment step, and the etching resist is a metal mask or a dry film light. Hinder.

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