JP2022118826A - Etching device - Google Patents

Abstract

To provide an etching device capable of solving problems where a washing liquid becomes uneven when the washing liquid is circulated, due to deposits generated in a washing treatment, and diffusing and removing property becomes unstable in the etching device to be used when a resin composition containing an alkali insoluble resin and an inorganic filler is subjected to an etching treatment by an etching liquid.SOLUTION: An etching device includes: an etching unit for removing a part of a resin composition by an etching liquid; and a washing and removing unit for completely removing the remaining resin composition by a washing and removing liquid. The etching device is such that: the washing and removing unit has a washing dip tank in which a washing liquid is put, and a washing liquid storage tank for recovering a washing liquid overflowing from the washing dip tank; and a two-dimensional or three-dimensional inclination is provided on the bottoms of the washing dip tank and the washing liquid storage tank.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to an etching apparatus used when etching a resin composition containing an alkali-insoluble resin and an inorganic filler with an etchant.

2. Description of the Related Art In recent years, with the miniaturization and high performance of electronic devices, there is a strong demand for the formation of fine wiring and the reduction of the coefficient of thermal expansion of circuit boards. Among them, as a means for lowering the thermal expansion coefficient of the insulating material, a method of increasing the filling of the insulating material, that is, increasing the content of the inorganic filler in the insulating material is known. Furthermore, as an insulating material, the use of alkali-insoluble resins with excellent moisture resistance, including epoxy resins, phenolic novolac curing agents, phenoxy resins, cyanate resins, etc., has been proposed. Insulating resin compositions containing these inorganic fillers and alkali-insoluble resins have excellent physical properties such as heat resistance, dielectric properties, mechanical strength, and chemical resistance. It is widely used as an interlayer insulating material for resists and multi-layer build-up wiring boards.

FIG. 1 is a schematic cross-sectional structural view of a solder resist pattern in which a portion other than connection pads 3 to be soldered on a circuit board is covered with a resin composition layer 4. As shown in FIG. The structure shown in FIG. 1 is called an SMD (Solder Masked Defined) structure, and is characterized in that the openings of the resin composition layer 4 are smaller than the connection pads 3 . The structure shown in FIG. 2 is called an NSMD (Non Solder Masked Defined) structure, and 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 FIG. 1 or FIG. 2 is formed by removing part of the resin composition layer 4 . As an etching method for removing a resin composition layer containing a resin composition containing an inorganic filler and an alkali-insoluble resin, an etching method is disclosed in which an immersion treatment is performed using a hydrazine-based chemical solution at 40° C. as an etchant. (See Patent Document 1, for example).

However, hydrazine is a poisonous substance and is not preferable because it has a large impact on the human body and a large environmental load. Therefore, an etching method using an etching solution containing an alkali metal hydroxide and an ethanolamine compound has been disclosed (for example, , see Patent Documents 2 to 4).

International Publication No. 2018/088345 pamphlet International Publication No. 2018/186362 pamphlet Japanese Patent No. 6774589 Japanese Patent No. 6674075

When a resin composition containing an alkali-insoluble resin and an inorganic filler is etched using an etching solution, the resin component is swollen in the etching solution, and the inorganic filler contained in the resin composition is removed in the etching treatment. When a portion of the resin component is partially dissolved and the swelling resin component shrinks in the subsequent water washing treatment, a portion of the inorganic filler is dissolved, so the original shape cannot be maintained and the resin composition is disintegrated in the washing liquid. Disperse and remove. Therefore, the resin composition containing the dispersed and removed inorganic filler precipitates in the washing liquid, and when the washing liquid is circulated for use, the washing liquid becomes non-uniform and the dispersing and removing performance becomes unstable. there were.

An object of the present invention is to circulate a washing solution in an etching apparatus used for etching a resin composition containing an alkali-insoluble resin and an inorganic filler with an etching solution, due to deposits generated in the washing treatment. It is an object of the present invention to provide an etching apparatus capable of solving the problem that the washing liquid becomes non-uniform and the dispersive removal property becomes unstable when the etching is performed.

The above problems are solved by the following means.

<1> In an etching apparatus used when etching a resin composition containing an alkali-insoluble resin and an inorganic filler with an etchant,
An etching unit in which the etching apparatus removes a part of the resin composition with an etching solution;
Equipped with a washing removal unit that completely removes the remaining resin composition with a washing removal liquid,
The washing removal unit has a washing dip tank containing washing liquid and a washing liquid storage tank for collecting the washing liquid overflowing from the washing dip tank,
An etching apparatus, wherein bottom surfaces of the washing dip tank and the washing liquid storage tank are inclined two-dimensionally or three-dimensionally.
<2> The washing removal unit has a sediment recovery pipe for sending the sediment accumulated on the bottom surface of the washing dip tank to the washing liquid storage tank,
The etching apparatus according to <1> above, wherein the precipitate collection pipe is connected from the washing dip tank to the washing liquid storage tank.

According to the etching apparatus of the present invention, it is possible to solve the problem that the washing liquid becomes non-uniform when the washing liquid is circulated due to the deposits generated in the washing process, and the dispersion removal property becomes unstable. can.

It is a schematic cross-sectional structural diagram showing an example of a solder resist pattern. It is a schematic cross-sectional structural diagram showing an example of a solder resist pattern. 1A to 1D are cross-sectional process diagrams showing an example of a method of forming a resist pattern using the etching apparatus of the present invention; 1 is a schematic cross-sectional structural view showing an example of a washing removal unit in an etching apparatus of the present invention; FIG. FIG. 4A is a top view and a perspective view showing an example of the inclination of the bottom surface of the washing dip tank in the etching apparatus of the present invention. FIG. 4A is a top view and a perspective view showing an example of the inclination of the bottom surface of the washing liquid storage tank in the etching apparatus of the present invention. FIG. 4A is a top view and a perspective view showing an example of the inclination of the bottom surface of the washing liquid storage tank in the etching apparatus of the present invention. FIG. 4A is a top view and a perspective view showing an example of the inclination of the bottom surface of the washing liquid storage tank in the etching apparatus of the present invention.

The etching apparatus of the present invention will be described in detail below.

The etching apparatus of the present invention is used when etching a resin composition containing an alkali-insoluble resin and an inorganic filler with an etchant. As an example of the etching process, a method of forming a solder resist pattern will be described with reference to FIG. In this method of forming a solder resist pattern, a solder resist pattern in which part or all of the solder connection pads 3 on the circuit board are exposed from the resin composition layer 4 can be formed.

In step (I), the copper foil 3' on the surface of the copper-clad laminate having the insulating layer 2 and the copper foil 3' is patterned by etching to form a conductor pattern, and the circuit board 1 having the solder connection pads 3 is formed. to form

In step (II), a resin composition layer 4 with a copper foil 6 is formed on the surface of the circuit board 1 so as to cover the entire surface. The resin composition layer 4 contains an alkali-insoluble resin and an inorganic filler.

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

In step (IV), the resin composition layer 4 is etched through the metal mask 5 with an etchant for resin composition until a part or all of the solder connection pads 3 are exposed.

In step (V), the metal mask 5 is removed by an etching process using an etchant for copper to form a solder resist pattern in which part or all of the solder connection pads 3 are exposed from the resin composition layer 4 .

As a result, a resist pattern having an SMD or NSMD structure can be formed without a residue of the resin composition layer 4, as shown in FIG. 3(V).

In the present invention, the etching solution is an etching solution for etching a resin composition containing an alkali-insoluble resin and an inorganic filler, and an alkaline aqueous solution containing a high-concentration alkali metal hydroxide can be used. can. Hereinafter, "an alkaline aqueous solution containing a high-concentration alkali metal hydroxide" may be referred to as an "alkali metal hydroxide-based etchant". Since the alkali-insoluble resin has the property of not being dissolved in an alkaline aqueous solution, it cannot be removed by an alkaline aqueous solution. However, by using an alkali metal hydroxide-based etchant, the resin composition containing the alkali-insoluble resin can be removed. When an alkali metal hydroxide-based etching solution that can be suitably used in the present invention is used, a portion of the inorganic filler contained in the resin composition is dissolved by the alkali metal hydroxide-based etching solution. A resin composition containing an insoluble resin can be etched.

The content of the inorganic filler in the resin composition according to the present invention is preferably 30 to 85% by mass with respect to 100% by mass of non-volatile matter in the resin composition. More preferably, it is 50 to 85% by mass. If the content of the inorganic filler is less than 30% by mass, etching may not progress because the inorganic filler is too small relative to the entire resin composition. On the other hand, when the content of the inorganic filler exceeds 85% by mass, the fluidity of the resin composition tends to decrease, and the flexibility tends to decrease, which may lead to poor practicality.

In the present invention, an alkali metal hydroxide-based etchant is preferably used as the etchant. The content of the alkali metal hydroxide in the alkali metal hydroxide-based etching solution is preferably 5% by mass or more and 50% by mass or less. If the content of the alkali metal hydroxide is less than 5% by mass, the solubility of the inorganic filler may be poor, and if the content of the alkali metal hydroxide exceeds 50% by mass, the alkali metal hydroxide Since substances tend to precipitate, the liquid may have poor stability over time. The content of alkali metal hydroxide is more preferably 15 to 45% by mass, more preferably 20 to 40% by mass.

As the alkali metal hydroxide, at least one compound selected from the group consisting of potassium hydroxide, sodium hydroxide and lithium hydroxide is preferably used. As the alkali metal hydroxide, one of these may be used alone, or two or more thereof may be used in combination.

In the present invention, the alkali metal hydroxide-based etching solution preferably further contains 1% by mass or more and 50% by mass or less of an ethanolamine compound. When an alkali metal hydroxide-based etching solution containing an ethanolamine compound is used, the ethanolamine compound penetrates into the resin composition, thereby promoting swelling of the resin composition and accelerating the dissolution and removal of the inorganic filler. and the removal rate of the resin composition is increased.

In the alkali metal hydroxide-based etching solution preferably used in the present invention, when the content of the ethanolamine compound is less than 1% by mass, the swelling property of the alkali-insoluble resin is poor, and the content of the ethanolamine compound is 0% by mass. The removal rate of the resin composition does not change compared to the case of . When the content of the ethanolamine compound exceeds 50% by mass, the compatibility with water is lowered, and phase separation is likely to occur, which may result in poor stability over time of the etching solution. The content of the ethanolamine compound is more preferably 5 to 40% by mass, still more preferably 10 to 35% by mass.

The ethanolamine compound may be of any type such as primary amine, secondary amine, tertiary amine, etc., and may be used singly or in combination of two or more. good. Examples of typical amine compounds include 2-aminoethanol, which is a primary amine; a mixture of primary and secondary amines (i.e., a primary amino group and a secondary amino 2-(2-aminoethylamino)ethanol which is a compound having a group and 2-(methylamino)ethanol and 2-(ethylamino)ethanol which are secondary amines; 2,2 which is a tertiary amine '-methyliminodiethanol (alias: N-methyl-2,2'-iminodiethanol), 2-(dimethylamino)ethanol and the like.

Additives such as a coupling agent, a leveling agent, a coloring agent, a surfactant, an antifoaming agent, and an organic solvent may be added to the alkali metal hydroxide-based etching solution as necessary. Examples of organic solvents include ketones such as acetone, methyl ethyl ketone and cyclohexanone; acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; and amide solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone. Among these, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like are preferable organic solvents because they have a large swelling property for alkali-insoluble resins.

Tap water, industrial water, pure water, or the like can be used as the water used for the etching solution. Of these, it is preferable to use pure water.

In the etching process according to the present invention, the temperature of the etchant is preferably in the range of 60-90.degree. The optimum temperature varies depending on the type of resin composition, the thickness of the resin composition layer, the shape of the pattern obtained by performing an etching treatment for removing the resin composition, etc., but the temperature of the etchant is more preferably 60 to 60. 85°C, more preferably 70 to 85°C.

In the present invention, the inorganic filler includes, for example, silicates such as silica, glass, clay and mica; oxides such as alumina, magnesium oxide, titanium oxide and silica; carbonates such as magnesium carbonate and calcium carbonate; Hydroxides such as aluminum oxide, magnesium hydroxide and calcium hydroxide; sulfates such as barium sulfate and calcium sulfate; Examples of inorganic fillers further include aluminum borate, aluminum nitride, boron nitride, strontium titanate, barium titanate, and the like. Among these, at least one compound selected from the group consisting of silica, glass, clay and aluminum hydroxide is more preferably used because it dissolves in an aqueous solution containing an alkali metal hydroxide. Silica is more preferable because of its excellent low thermal expansion property, and spherical fused silica is particularly preferable. As the inorganic filler, one of these may be used alone, or two or more may be used in combination.

The alkali-insoluble resin related to the present invention will be explained. The alkali-insoluble resin is not particularly limited except for the property of not being dissolved or dispersed in an alkaline aqueous solution. Specifically, it is a resin that contains a very small amount of carboxyl group-containing resin or the like necessary for dissolving in an alkaline aqueous solution, and the acid value (JIS K2501 : 2003) is less than 40 mg KOH/g. More specifically, the alkali-insoluble resin is a resin containing an epoxy resin and a thermosetting agent that cures 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, monoethanolamine, Organic compounds such as diethanolamine, triethanolamine, methylamine, dimethylamine, ethylamine, diethylamine, triethylamine, cyclohexylamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, trimethyl-2-hydroxyethylammonium hydroxide (choline) Aqueous solutions containing alkaline compounds are mentioned.

Examples of epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin and bisphenol S type epoxy resin; novolak type epoxy resins such as phenol novolak type epoxy resin and cresol novolak type epoxy resin; mentioned. Further, examples of epoxy resins include biphenyl-type epoxy resins, naphthalene-type epoxy resins, anthracene-type epoxy resins, phenoxy-type epoxy resins, and fluorene-type epoxy resins. As the epoxy resin, one of these may be used alone, or two or more may be used in combination.

The thermosetting agent is not particularly limited as long as it has a function of curing the epoxy resin. cyanate ester resin and the like. As the thermosetting agent, one of these may be used alone, or two or more thereof may be used in combination.

In addition to the above curing agent, a curing accelerator may also be contained. Examples of curing accelerators include organic phosphine compounds, organic phosphonium salt compounds, imidazole compounds, amine adduct compounds, tertiary amine compounds and the like. As the curing accelerator, one of these may be used alone, or two or more thereof may be used in combination. When using a cyanate ester resin as a thermosetting agent, an organometallic compound used as a curing catalyst may be added for the purpose of shortening the curing time. Organic metal compounds include organic copper compounds, organic zinc compounds, organic cobalt compounds, and the like.

The etching apparatus of the present invention will be described in detail with reference to the drawings. The etching apparatus of the present invention comprises an etching unit (not shown) for partially removing the resin composition with an etchant, and a washing removal unit 21 for completely removing the remaining resin composition with a washing removal solution. . FIG. 4 is a schematic cross-sectional structural diagram showing an example of the washing removal unit 21 in the etching apparatus of the present invention. The washing removal unit 21 has a washing dip tank 11 containing washing liquid 10 and a washing liquid storage tank 15 for collecting the washing liquid 10 overflowing from the washing dip tank 11 .

The object to be processed having the resin composition coming out of the etching unit is conveyed into the water washing removal unit 21 from the inlet 14 by the conveying roll pair 13 . In the water washing removal unit 21, the object to be treated is immersed in the washing liquid 10 in the water washing dip bath 11 to remove the resin composition. A washing dip tank 11 containing a washing liquid 10, a washing liquid storage tank 15 for collecting the washing liquid 10 overflowing from the washing dip tank 11, and a sediment derived from a resin composition accumulated on the bottom surface of the washing dip tank 11 is washed with water. It has a sediment collection pipe 19 for feeding to the liquid storage tank 15 . A substrate 12 having a resin composition layer formed thereon is exemplified as an object to be processed having a resin composition. In addition, the bottom surfaces of the washing dip tank 11 and the washing liquid storage tank 15 are provided with two-dimensional or three-dimensional inclinations. A sediment recovery pipe 19 is connected from the washing dip tank 11 to the washing liquid storage tank 15 .

The washing liquid 10 is supplied from the washing liquid suction port 16 of the washing liquid storage tank 15 below the washing removal unit 21 to the washing dip tank 11 through the washing liquid supply pipe 17 by a washing liquid supply pump (not shown). , to overflow. The overflowed washing liquid 10 is collected in the washing liquid storage tank 15 through the washing liquid collection pipe 18 , so that the washing liquid 10 circulates between the washing dip tank 11 and the washing liquid storage tank 15 . Further, in the washing removal unit 21 shown in FIG. 4, the bottom surfaces of the washing dip tank 11 and the washing liquid storage tank 15 are inclined. The resin composition washed and removed in the water washing dip tank 11 moves along the slope of the bottom surface of the water washing dip tank 11, and the resin composition in the washing liquid 10 is suppressed from circulating in the washing liquid 10. be able to.

Furthermore, the resin composition-derived sediment that has moved to a lower position along the slope of the bottom surface of the washing dipping tank 11 is discharged from the sediment discharge port 20 to the washing liquid storage tank 15 via the sediment collection pipe 19. and sent. At this time, it is preferable to install an on-off valve 23 in the sediment collection pipe 19 so that the discharge amount of the sediment can be adjusted. In the washing liquid storage tank 15, sediments move along the slope of the bottom surface. As a result, it is possible to prevent sediment having a large specific gravity from accumulating on the bottom surface of the washing liquid storage tank 15 and circulating again to the washing liquid 10 in the washing dip tank 11 .

In the present invention, the preferred diameters of the sediment discharge port 20 and the sediment recovery pipe 19 vary depending on the size of the washing dip tank 11, but are usually in the range of 10-40 mm. Moreover, the position of the sediment discharge port 20 can be anywhere as long as the sediment moves along the slope of the bottom surface of the water washing dip tank 11, and can be discharged from one place or a plurality of places. may be discharged simultaneously or with a time lag. In addition, if the sediment discharge port 20 is installed on the side of the washing dip tank 11, the sediment discharge efficiency is deteriorated, which is not preferable.

In the present invention, the shape and material of the transport roll pair 13 are not restricted as long as they can transport the substrate 12, and for example, polypropylene, polyvinyl chloride, Teflon (registered trademark), etc. can be used. Moreover, the installation positions and the number of the transport roll pairs 13 are not particularly limited to the installation positions and the number shown in FIG. 4 as long as the substrate 12 can be transported.

In the present invention, the slopes provided on the bottom surfaces of the washing dip tank 11 and the washing liquid storage tank 15 will be described. The slope provided on the bottom surface has a two-dimensional or three-dimensional structure. An example of a two-dimensional structure will be described in detail with reference to FIG. FIG. 5(I) is a top view showing an example of inclination of the bottom surface of the washing dip tank 11, and FIG. 5(II) is a perspective view showing an example of the same inclination. As indicated by the dotted line in FIG. 5, the slope of the bottom surface is a valley fold, and the bottom surface of the washing dip tank 11 has a two-dimensional structure. The washing liquid 10 is supplied from the washing liquid supply port 22 through the washing liquid supply pipe 17 to the washing dip tank 11, and the resin composition removed by the washing process settles as sediment on the bottom surface of the washing dip tank 11, The sediment moves along the bottom slope. The sediment that has moved along the two-dimensional slope is sent from the sediment discharge port 20 to the washing liquid storage tank 15 through the sediment collection pipe 19 .

Next, the three-dimensional structure will be explained with reference to FIGS. 6 to 8. FIG. 6 to 8 (I) are all top views showing examples of inclination of the bottom surface of the washing liquid storage tank 15 of the present invention, and FIGS. 6 to 8 (II) are examples of the same inclination. It is a perspective view showing. 6 to 8, the slope of the bottom surface is a valley fold, and the bottom surface of the washing liquid storage tank 15 has a three-dimensional structure. The bottom surface of the washing liquid storage tank 15 is divided into two sides in FIG. 6, three sides in FIG. 7, and four sides in FIG. The slopes (tilt angles) of the divided slopes may be the same or different, and the position of the bottom after moving along the slopes can be freely determined. The greater the tilt angle, the greater the acceleration of movement, but the structure becomes more complicated and the maintainability may deteriorate.

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.

(Example 1)
60% by mass of spherical fused silica as an inorganic filler, 10% by mass of a biphenyl aralkyl type epoxy resin as an epoxy resin, 20% by mass of a phenol novolac type cyanate resin as a thermosetting agent, and 1% by mass of triphenylphosphine as a curing accelerator. In addition, a coupling agent and a leveling agent were added to make the total amount 100% by mass, and mixed with methyl ethyl ketone and cyclohexanone as media to obtain a liquid resin composition.

Next, after applying the liquid resin composition onto a polyethylene terephthalate film (thickness: 38 μm), the film was dried at 100° C. for 5 minutes to remove the medium. As a result, an A-stage resin composition layer made of a resin composition containing an alkali-insoluble resin and an inorganic filler was formed with a film thickness of 20 μm. The A stage is a state before the epoxy resin and the thermosetting agent initiate a curing reaction.

The polyethylene terephthalate film was peeled off, and both sides of an epoxy resin glass cloth base copper clad laminate (area 408 mm x 510 mm, copper foil thickness 12 µm, base thickness 0.1 mm) were laminated using a thermocompression laminator at a temperature of 100°C. After thermocompression bonding at a pressure of 0.4 MPa and transferring onto a copper foil, heating at 100° C. for 30 minutes to form a B-stage resin composition layer, a substrate 12 having a resin composition layer formed thereon was obtained. . The B stage is an intermediate stage of the curing reaction in which the curing reaction between the epoxy resin and the thermosetting agent has started and the curing reaction has not yet reached a completely cured state called the C stage.

Next, as an etchant, an aqueous solution of 30% by mass of potassium hydroxide, 30% by mass of N-methylethanolamine, and 40% by mass of water (liquid temperature 80° C.) was used as the etchant, and the etchant dip tank in the etching unit , the substrate 12 was immersed for 70 seconds. After that, the washing removal unit 21 has a washing dip tank 11 and a washing liquid storage tank 15 for collecting the washing liquid 10 overflowing from the washing dip tank 11 . It has a dimensional inclination and has a sediment recovery pipe 19 for sending the sediment accumulated on the bottom surface of the washing dip tank 11 to the washing liquid storage tank 15, and the sediment collection pipe 19 serves as a sediment outlet. The etching apparatus connected from 20 to the washing liquid storage tank 15 was used to wash and remove the resin composition while circulating the washing liquid 10 from the washing liquid storage tank 15 to the washing dip tank 11 . The time of immersion in the washing dip tank 11 was set to 40 seconds. After the water washing treatment, the washing liquid 10 remaining on the surface was washed off by spray treatment with pure water.

Precipitates that settled on the bottom surfaces of the washing dip tank 11 and the washing liquid storage tank 15 and moved along the slope of the bottom surfaces of the 1st, 25th, 50th, 75th, and 100th etching-treated sheets. As a result of checking for the presence or absence, no sediment or dissolved matter derived from the resin composition was found on the bottom surface of the water washing dip tank 11 even after the 100 wafers were etched. On the other hand, on the bottom of the washing liquid storage tank 15, precipitation of dissolved fused silica was confirmed after processing 75 wafers.

When the presence or absence of residues of the resin composition after the etching treatment was observed with an optical microscope, no residues were observed even on 100 substrates after the etching treatment.

(Example 2)
Etching was performed in the same manner as in Example 1, except that an etching apparatus in which the bottom surfaces of the washing dip tank 11 and the washing liquid storage tank 15 were provided with a three-dimensional inclination was used.

In the first, 25th, 50th, 75th, and 100th etching-treated sheets, the resin composition settled on the bottom surfaces of the washing dip tank 11 and the washing liquid storage tank 15 and moved along the slope of the bottom surface. As a result of confirming the presence or absence of the originating precipitates, no precipitates were found on the bottom surface of the water washing dip tank 11 even after etching 100 sheets. On the other hand, on the bottom surface of the washing liquid storage tank 15, sediment was confirmed after processing 75 wafers.

When the presence or absence of residues of the resin composition after the etching treatment was observed with an optical microscope, no residues were observed even on 100 substrates after the etching treatment.

(Comparative example 1)
Etching was carried out in the same manner as in Example 1, except that an etching apparatus having a flat structure with no slope on the bottom surface of the washing dip tank 11 and the washing liquid storage tank 15 was used.

In the first, 25th, 50th, 75th, and 100th etching-treated sheets, the presence or absence of precipitates derived from the resin composition that settled on the bottom surfaces of the washing dip tank 11 and the washing liquid storage tank 15 was confirmed. However, after processing 25 wafers, deposits were found on the bottom surfaces of the washing dip tank 11 and the washing liquid storage tank 15 .

Observation with an optical microscope for the presence or absence of a residue of the resin composition after the etching treatment revealed that the 25th etching-treated substrate had partially insufficient removal by washing with water.

INDUSTRIAL APPLICABILITY The etching apparatus of the present invention can be applied to etching an insulating resin composition layer containing an inorganic filler and having excellent heat resistance, dielectric properties, mechanical strength, chemical resistance, and the like. For example, it can be applied to fine processing of insulating resin in multilayer buildup wiring boards, component built-in module substrates, flip chip package substrates, motherboards for mounting package substrates, and the like.

Reference Signs List 1 Circuit board 2 Insulating layer 3′ Copper foil 3 Solder connection pad, connection pad 4 Resin composition layer 5 Metal mask 6 Copper foil 10 Washing liquid 11 Washing dip tank 12 Substrate 13 Transfer roll pair 14 Input port 15 Washing liquid storage tank 16 Washing liquid suction port 17 Washing liquid supply pipe 18 Washing liquid recovery pipe 19 Sediment collection pipe 20 Sediment discharge port 21 Washing liquid removal unit 22 Washing liquid supply port 23 Open/close valve

Claims (2)

In an etching apparatus used when etching a resin composition containing an alkali-insoluble resin and an inorganic filler with an etchant,
An etching unit in which the etching apparatus removes a part of the resin composition with an etching solution;
Equipped with a washing removal unit that completely removes the remaining resin composition with a washing removal liquid,
The washing removal unit has a washing dip tank containing washing liquid and a washing liquid storage tank for collecting the washing liquid overflowing from the washing dip tank,
An etching apparatus, wherein bottom surfaces of the washing dip tank and the washing liquid storage tank are inclined two-dimensionally or three-dimensionally. the washing removal unit having a sediment collection pipe for conveying the sediment accumulated on the bottom of the washing dip tank to the washing liquid storage tank;
2. An etching apparatus according to claim 1, wherein the sediment collection pipe is connected from the washing dip tank to the washing liquid storage tank.

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