JP2022032447A - Etching device - Google Patents

Abstract

To provide an etching device used when a resin composition layer including an alkali-insoluble resin and an inorganic filler is immersed in an etching solution, capable of removing quickly the resin composition layer having become unable to maintain its film shape and of supplying quickly a new etching solution.SOLUTION: An etching device used when a resin composition layer including an alkali-insoluble resin and an inorganic filler is etched with an etching solution, includes an etching unit for the etching device to remove the resin composition layer. The etching unit includes: a dip tank in which an object to be treated having the resin composition layer is immersed in the etching solution; an etching liquid supply pump; and etching liquid supply slit nozzles.SELECTED DRAWING: Figure 4

Description

The present invention relates to an etching apparatus used for etching a resin composition layer containing an alkali-insoluble resin and an inorganic filler with an etching solution.

In recent years, with the miniaturization and higher performance of electronic devices, there is a strong demand for the formation of fine wiring and the reduction of the coefficient of thermal expansion in circuit boards. Among them, as a means for reducing 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. Further, it has been proposed to use an alkali-insoluble resin which contains an epoxy resin, a phenol novolac-based curing agent, a phenoxy resin, a cyanate resin and the like as an insulating material and has excellent moisture resistance. The insulating resin composition containing these inorganic fillers and alkali-insoluble resins has excellent physical properties such as heat resistance, dielectric properties, mechanical strength, and chemical resistance, and is a solder used for the outer layer surface of a circuit board. It is widely used as an interlayer insulating material used for resists and multilayer build-up wiring boards.

FIG. 1 is a schematic cross-sectional structural diagram of a solder resist pattern in which a portion other than the connection pad 3 to be soldered on the circuit board is covered with the resin composition layer 4. 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 that of the connection pad 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 that of the connection pad 3.

The opening of the resin composition layer 4 in FIG. 1 or FIG. 2 is formed by removing a part of the resin composition layer 4. As an etching method for removing the resin composition layer 4 containing an inorganic filler and an alkali-insoluble resin, an etching method performed by an immersion treatment using a hydrazine-based chemical solution at 40 ° C. as an etching solution is disclosed (for example, Patent Document 1). reference). Further, in Patent Document 1, the preferable content of the inorganic filler is 30 to 90% by mass, and the more preferable content is 50 to 50 to 90% by mass, based on the total solid content of the resin composition constituting the resin composition layer 4. It is stated that it is 85% by mass.

In the etching method of removing the resin composition layer 4 containing the inorganic filler and the alkali-insoluble resin by a dipping treatment, the resin composition layer 4 is removed by dissolving a part of the inorganic filler and making it impossible to maintain the film shape. can do. For uniform etching, it is important to promptly remove the resin composition layer 4 whose film shape cannot be maintained from the etching surface and supply a new etching solution to the etching surface. When the removal of the resin composition layer 4 whose film shape cannot be maintained and the supply of the etching solution become non-uniform in the etching surface, the etching becomes non-uniform, and the etching process is not performed as designed or partially. There is a portion where a residue of the resin composition layer 4 is generated in the resin composition layer 4, which may cause a contact failure of the three connection pads when forming the solder resist pattern, which may lead to a decrease in the yield in production. (See, for example, Patent Document 2).

International Publication No. 2018/08834 Pamphlet Japanese Unexamined Patent Publication No. 2020-41099

An object of the present invention is to quickly remove a resin composition layer whose film shape cannot be maintained in an etching apparatus used for dipping a resin composition layer containing an alkali-insoluble resin and an inorganic filler with an etching solution. The present invention is to provide an etching apparatus capable of promptly supplying a new etching solution.

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

(1) In an etching apparatus used for etching a resin composition layer containing an alkali-insoluble resin and an inorganic filler with an etching solution.
The etching apparatus has an etching unit for removing the resin composition layer.
An etching apparatus characterized in that the etching unit has a dip tank in which an object to be processed having a resin composition layer is immersed in an etching solution, an etching solution supply pump, and an etching solution supply slit nozzle.
(2) The etching apparatus according to (1) above, wherein the content of the inorganic filler in the resin composition constituting the resin composition layer is 30 to 85% by mass.
(3) The etching apparatus according to (1) or (2) above, wherein the etching solution contains 5 to 50% by mass of an alkali metal hydroxide.

In the etching apparatus used for etching the resin composition layer containing the alkali-insoluble resin and the inorganic filler with the etching solution, the etching solution is jet-circulated in the dip tank by having the etching solution supply slit nozzle. The resin composition layer whose film shape cannot be maintained can be quickly removed, and a new etching solution can be quickly supplied.

It is a schematic cross-sectional structure diagram which shows an example of a solder resist pattern. It is a schematic cross-sectional structure diagram which shows an example of a solder resist pattern. It is sectional drawing which shows an example of the forming method of the resist pattern performed using the etching apparatus of this invention. It is a schematic cross-sectional structure diagram which shows an example of the etching apparatus of this invention.

Hereinafter, the etching apparatus of the present invention will be described in detail.

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

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

In the step (II), the resin composition layer 4 with the copper foil 9 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 the step (III), the copper foil 9 on the resin composition layer 4 is patterned by an etching process with an etching solution for copper to form a metal mask 8 for etching the resin composition layer.

In step (IV), the resin composition layer 4 is etched with the etching solution through the metal mask 8 until a part or all of the solder connection pad 3 is exposed.

In the step (V), the metal mask 8 is removed by an etching process with an etching solution for copper to form a solder resist pattern in which a part or all of the solder connection pad 3 is exposed from the resin composition layer 4.

This makes it possible to form a resist pattern having an SMD structure or an NSMD structure without the 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 layer containing an alkali-insoluble resin and an inorganic filler, and is a hydrazine-based etching solution and an alkaline aqueous solution containing a high-concentration alkali metal hydroxide. Etc. can be used, but an alkaline aqueous solution containing a high concentration of alkali metal hydroxide (hereinafter, "an alkaline aqueous solution containing a high concentration of alkali metal hydroxide" is referred to as an "alkali metal hydroxide-based etching solution". In some cases). Since the alkali-insoluble resin has the property of not being dissolved in the alkaline aqueous solution, it cannot be originally removed by the alkaline aqueous solution. However, by using the etching solution according to the present invention, the resin composition layer containing the alkali-insoluble resin can be removed. When an alkaline aqueous solution containing a high-concentration alkali metal hydroxide that can be suitably used in the present invention is used, a part of the inorganic filler in the resin composition layer is provided by the aqueous solution containing the alkali metal hydroxide having a high concentration. Can be etched by dissolving the film and making it impossible to maintain the shape of the film.

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 hydroxylation may be poor. Since the precipitation of substances is likely to occur, the stability of the liquid over time may be inferior. The content of the alkali metal hydroxide is more preferably 15 to 45% by mass, still more preferably 20 to 40% by mass.

A coupling agent, a leveling agent, a colorant, a surfactant, a defoaming agent, an organic solvent and the like can be appropriately added to the alkali metal hydroxide-based etching solution, if necessary. Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone and cyclohexanone; acetates 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; amide-based solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone can be mentioned. Among them, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like have a large swelling property of the alkali-insoluble resin and are preferable.

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 of them may be used in combination.

Further, the alkali metal hydroxide-based etching solution according to the present invention preferably contains 1% by mass or more and 50% by mass or less of an ethanolamine compound in addition to the alkali metal hydroxide. When an alkali metal hydroxide-based etching solution containing an ethanolamine compound is used, the ethanolamine compound permeates into the resin composition layer, thereby promoting the swelling of the resin composition layer and dissolving and removing the inorganic filler. Is accelerated, and the removal speed of the resin composition layer is increased.

In the alkali metal hydroxide-based etching solution according to 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. In comparison, the removal rate of the resin composition layer does not change. When the content of the ethanolamine compound exceeds 50% by mass, the compatibility with water becomes low and phase separation is likely to occur, so that the stability of the etching solution with time may be inferior. 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 kind such as a primary amine, a secondary amine, or a tertiary amine, and may be used alone or in combination of two or more. good. An example of a typical amine compound is 2-aminoethanol, which is a primary amine; a mixture of a primary amine and a secondary amine (that is, a primary amino group and a secondary amino in one molecule). 2- (2-Aminoethylamino) ethanol which is a compound having a group); 2- (methylamino) ethanol which is a secondary amine, 2- (ethylamino) ethanol; 2,2 which is a tertiary amine ′ -Methyliminodiethanol (also known as N-methyl-2,2′-iminodiethanol), 2,2′-ethyliminodiethanol (also known as N-ethyl-2,2′-iminodiethanol), 2- (dimethylamino) ) Ethanol, triethanolamine and the like can be mentioned. Of these, 2-aminoethanol and 2- (2-aminoethylamino) ethanol are more preferable.

Examples of the hydrazine-based etching solution include an etching solution using hydrazine monohydrate. In addition, ethylenediamine can be used in combination with hydrazine monohydrate. Hydrazine monohydrate has a strong reducing property and can decompose and remove the resin composition layer according to the present invention. However, since it falls under the category of deleterious substances under the Poisonous and Deleterious Substances Control Law, is harmful to human health, and has a large burden on the environment, it is preferable to use an alkali metal hydroxide-based etching solution.

The etching solution according to the present invention is an alkaline aqueous solution. As the water used for the etching solution, tap water, industrial water, pure water or the like can be used. Of these, it is preferable to use pure water.

In the etching process according to the present invention, the temperature of the etching solution is preferably in the range of 60 to 90 ° C. The optimum temperature varies depending on the type of resin composition constituting the resin composition layer, the thickness of the resin composition layer, the shape of the pattern obtained by performing the etching treatment for removing the resin composition layer, and the like. The temperature is more preferably 60 to 85 ° C, still more preferably 70 to 85 ° C.

The content of the inorganic filler in the resin composition constituting the resin composition layer is preferably 30 to 85% by mass with respect to 100% by mass of the non-volatile content in the resin composition. When the content of the inorganic filler is less than 30% by mass, the etching does not proceed because the amount of the inorganic filler as a site dissolved by the alkali metal hydroxide-based etching solution is too small with respect to the entire resin composition. In some cases. When the content of the inorganic filler exceeds 85% by mass, the flexibility tends to decrease due to the decrease in the fluidity of the resin composition, which is inferior in practicality.

In the present invention, examples of the inorganic filler include 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; water. Hydroxides such as aluminum oxide, magnesium hydroxide and calcium hydroxide; sulfates such as barium sulfate and calcium sulfate can be mentioned. Further, examples of the inorganic filler 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 has high solubility in an etching solution. Silica is more preferable because it has 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 of them may be used in combination.

In the present invention, the resin composition may contain an organic filler in addition to the inorganic filler. When the organic filler is contained, the content of the organic filler is preferably about 5 to 30% by mass with respect to 100% by mass of the non-volatile content in the resin composition. Examples of the organic filler include polytetrafluoroethylene (PTFE), fluoroethylene-propylene copolymer (FEP), perfluoroalkoxy polymer (PFA), polychlorotrifluoroethylene (PCTFE), and tetrafluoroethylene-. Examples thereof include at least one fluororesin selected from the group consisting of chlorotrifluoroethylene copolymer (TFE / CTFE) and ethylene-chlorotrifluoroethylene copolymer (ECTFE). One of these resins may be used alone, or two or more of these resins may be used in combination.

The alkali-insoluble resin according to the present invention will be described. The alkali-insoluble resin is not particularly limited except that it is not dissolved or dispersed in an aqueous alkaline solution. Specifically, it is a resin having a very small content of a carboxyl group-containing resin or the like required for dissolving in an alkaline aqueous solution, and has an acid value (JIS K2501) which is an index of the content of free carboxyl groups in the resin. : 2003) is less than 40 mgKOH / 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 the alkaline aqueous solution include an aqueous solution containing an inorganic alkaline compound such as an alkali metal silicate, an alkali metal hydroxide, an alkali metal phosphate, an alkali metal carbonate, an ammonium phosphate, and an ammonium carbonate, and a monoethanolamine. Organics such as diethanolamine, triethanolamine, methylamine, dimethylamine, ethylamine, diethylamine, triethylamine, cyclohexylamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, trimethyl-2-hydroxyethylammonium hydroxide (choline). Examples thereof include an aqueous solution containing an alkaline compound.

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; novolak type epoxy resins such as phenol novolac type epoxy resin and cresol novolak type epoxy resin. Can be mentioned. Further, examples of the epoxy resin include biphenyl type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, phenoxy type epoxy resin, fluorene type epoxy resin and the like. As the epoxy resin, one of these may be used alone, or two or more of them may be used in combination.

The heat-curing agent is not particularly limited as long as it has a function of curing the epoxy resin, but preferred ones are a phenol-based curing agent, a naphthol-based curing agent, an active ester-based curing agent, a benzoxazine-based curing agent, and the like. Examples thereof include cyanate ester resin. 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 can be further contained. Examples of the curing accelerator include an organic phosphine compound, an organic phosphonium salt compound, an imidazole compound, an amine adduct compound, a tertiary amine compound 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 a cyanate ester resin is used as a thermosetting agent, an organic metal compound used as a curing catalyst may be added for the purpose of shortening the curing time. Examples of the organometallic compound include an organocopper compound, an organozinc compound, an organocobalt compound and the like.

As described above, in the present invention, when the resin composition layer containing the alkali-insoluble resin and 30 to 85% by mass of the inorganic filler is etched using the etching solution, the inorganic filler in the resin composition layer becomes high. The removal of the resin composition layer proceeds by being dissolved and removed by an aqueous solution containing an alkali metal hydroxide having a concentration. Further, when the etching solution according to the present invention contains an ethanolamine compound, the ethanolamine compound permeates into the resin composition layer, thereby promoting the swelling of the resin composition layer and dissolving and removing the inorganic filler. It will be accelerated.

The etching apparatus of the present invention will be described in detail with reference to the drawings. FIG. 4 is a schematic cross-sectional structural view showing an example of the etching apparatus of the present invention, in which the object to be treated having the resin composition layer is conveyed in a state of being immersed in the etching solution 10 in the dip tank 11 by the conveying roll pair 13. This is an etching apparatus for etching the resin composition layer.

The etching apparatus of the present invention has an etching unit 20 for removing the resin composition layer with an etching solution. The etching unit 20 has a dip tank 11 containing an etching solution 10 in which an object to be treated having a resin composition layer is immersed, an etching solution supply pump (not shown), and an etching solution supply slit nozzle 21. The etching solution supply pump is a pump for supplying the etching solution 10 to the dip tank 11. The storage tank 15 for collecting the etching liquid 10 overflowing from the dip tank 11 also serves as a tank for supplying the etching liquid to the dip tank 11. That is, the etching unit 20 is a unit that circulates and uses the etching solution 10. As the object to be treated having the resin composition, the substrate 12 on which the resin composition layer was formed was exemplified.

The etching liquid 10 is sent from the etching liquid suction port 16 of the storage tank 15 at the bottom of the apparatus to the etching liquid supply pipe 17 by an etching liquid supply pump (not shown), and is connected to the outlet of the etching liquid supply pipe 17. It is supplied to the dip tank 11 via the etching solution supply slit nozzle 21. Etching liquid supply By supplying the etching liquid through the slit nozzle 21, the new etching liquid 10 is uniformly and continuously supplied to the etching surface on the surface of the substrate 12, and the etching liquid 10 in the dip tank 11 is made to flow. , The etching solution 10 is jet-circulated, and the resin composition layer whose film shape cannot be maintained by etching can be quickly removed. The etching solution 10 overflowing from the dip tank 11 returns to the storage tank 15 from the etching solution recovery port 18 via the etching solution recovery tubes 19 and 19'.

In order to uniformly supply the etching solution 10, the etching solution supply slit nozzle 21 is installed in the gap between the transport roll pairs 13 so that the slit is substantially parallel to the width direction (direction perpendicular to the transport direction). Is preferable. When there are three or more pairs of transport rolls 13, there are two or more gaps, but the etching solution supply slit nozzle 21 may be installed in all the gaps, or the etching solution supply slit nozzle 21 is not installed. There may be a gap. Further, two etching solution supply slit nozzles 21 of the upper portion and the lower portion of the dip tank 11 may be installed in one gap, or the etching solution supply slit nozzle 21 of only the upper portion or only the lower portion may be installed. You may install it. In one gap, the etching solution supply slit nozzle 21 may be installed in the upper portion of the dip tank 11, and in another gap, the etching solution supply slit nozzle 21 may be installed in the lower portion of the dip tank 11. In the gap, the etching solution supply slit nozzle 21 may be installed in both the upper portion and the lower portion of the dip tank 11.

Further, in the etching solution supply slit nozzle 21, the length of the slit in the width direction is preferably 1 times or more the length in the width direction of the substrate 12. Then, a plurality of etching liquid supply slit nozzles 21 may be installed in the width direction of one gap, or one etching liquid supply slit nozzle 21 may be installed in the width direction.

Further, the lip portion of the etching solution supply slit nozzle 21 is installed at a position lower than the liquid level of the etching solution 10 so that the etching solution 10 is uniformly supplied without generating bubbles, and the dip tank 11 is installed. It is preferable that the etching solution 10 is discharged from the etching solution supply slit nozzle 21 into the etching solution 10 inside. The orientation of the etching solution supply slit nozzle 21 is not particularly limited, but in order for the etching solution 10 to be uniformly supplied and circulated by jet flow, the etching solution 10 supplied from the etching solution supply slit nozzle 21 in the upper portion is directed downward. The etching solution 10 is discharged in the downstream direction in the transport direction, and the etching solution 10 supplied from the etching solution supply slit nozzle 21 in the lower portion is discharged in the downstream direction in the transport direction rather than directly above. In addition, it is preferable to incline the etching solution supply slit nozzle 21 in the downstream direction in the transport direction.

If the etching liquid 10 discharged from the etching liquid supply slit nozzle 21 vigorously hits the substrate 12, the etching process may become non-uniform. Therefore, the supply capacity of the etching liquid supply slit nozzle and the etching liquid supply slit nozzle 21 It is preferable to adjust the orientation as appropriate.

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, PTFE and the like can be used. Further, the installation position and number of the transport roll pairs 13 are not particularly limited to the installation positions and numbers shown in FIG. 4 as long as the substrate 12 can be transported.

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

(Example)
Spherical molten silica 60% by mass as an inorganic filler, biphenyl aralkyl type epoxy resin 10% by mass as an epoxy resin, phenol novolac type cyanate resin 10% by mass as a heat curing agent, and triphenylphosphine 1% by mass as a curing accelerator. In addition, a coupling agent and a leveling agent were added, and the total amount was 100% by mass, and the mixture was mixed with methyl ethyl ketone and cyclohexanone as a medium to obtain a liquid resin composition.

Next, the liquid resin composition was applied onto a polyethylene terephthalate film (thickness 38 μm) and then dried at 100 ° C. for 5 minutes to remove the medium. As a result, an A-stage resin composition layer composed of a resin composition containing an alkali-insoluble resin and an inorganic filler was formed with a film thickness of 15 μm. The A stage is a state before the epoxy resin and the thermosetting agent start the curing reaction.

Subsequently, a peelable metal foil in which a copper foil having a thickness of 3 μm, a peeling layer, and a carrier foil are laminated in this order is prepared, and the copper foil and the resin composition layer are thermocompression bonded so as to be in contact with each other. , The peeling layer and the carrier foil were peeled off to obtain a resin composition layer 4 with a copper foil 9.

The conductor pattern is formed by peeling off the polyethylene terephthalate film and patterning the copper foil 3'of an epoxy resin glass cloth base copper-clad laminate (area 400 mm x 510 mm, copper foil thickness 12 μm, base material thickness 0.1 mm) by etching. After forming and forming the circuit board 1, hot-pressing it at a temperature of 100 ° C. and a pressure of 0.4 MPa using a heat-bonding type laminator, transferring it onto the circuit board 1, and then heating it at 100 ° C. for 30 minutes. The resin composition layer 4 of the B stage was formed. The B stage is an intermediate stage of the curing reaction in which the curing reaction between the epoxy resin and the thermosetting agent is started and has not reached the completely cured state called the C stage.

Subsequently, the copper foil 9 on the resin composition layer 4 is patterned by an etching process with an etching solution for copper so as to have the SMD structure or NSMD structure shown in the step (III) of FIG. A copper etching process for forming the metal mask 8 for etching the composition layer was carried out, and the resin composition layer 4 with the metal mask 8 was prepared as the substrate 12. As for the SMD structure or NSMD structure, one set was arranged at 32 locations at equal intervals on a 400 mm × 510 mm substrate.

Next, an aqueous solution of potassium hydroxide 30% by mass, 2- (methylamino) ethanol 30% by mass, and water 40% by mass (liquid temperature 80 ° C.) was used as the etching solution, and the etching solution was used by an etching solution supply pump. In the etching apparatus (FIG. 4) supplied to the dip tank 11 via the supply pipe 17 and the etching liquid supply slit nozzle 21, the etching liquid 10 is ejected by using both the etching liquid supply pipe 17 and the etching liquid supply slit nozzle 21. While circulating, the resin composition layer 4 was subjected to an etching treatment under the condition of being immersed for 90 seconds. After the etching treatment, the etching solution 10 remaining and adhering to the surface of the resin composition layer 4 was washed by a spray treatment with pure water.

In order to evaluate the stability of the etching process, 10 sheets were continuously etched, the metal mask 8 was removed on the 1st, 5th, and 10th sheets, and 32 points on the substrate 1 were shown in FIG. 3 ( The length a (mask diameter 100 μm) of the SMD structure portion of V) was measured, and it was judged that the portion where the length a was opened at 130 μm ± 5 μm could be opened, and the opening was evaluated according to the following criteria. Table 1 shows the results of stability and the results of confirming the residue of the NSMD structure portion (NSMD residue) with an optical microscope.

(Aperture stability)
◯: All 32 locations have been opened.
Δ: The number of places where the opening process is performed is less than 30 places and 32 places.
X: The number of places where the opening process is performed is less than 30 places.

(Comparative example)
As a comparative example, Table 1 also shows the results of evaluation based on the same criteria as in the examples, except that the etching solution 10 is circulated using only the etching solution supply tube 17 without using the etching solution supply slit nozzle. Described in.

As is clear from the results in Table 1, the dip tank 11 has an etching unit for removing the resin composition layer, and the etching unit is used to immerse the object to be treated having the resin composition layer in the etching solution 10. The etching solution 10 is jet-circulated by the etching apparatus having the etching solution supply pump 17 and the etching solution supply slit nozzle 21, so that the etching solution supply slit nozzle 21 is not used and only the etching solution supply tube 17 is used. It can be seen that the etching process can be uniformly performed as designed without generating a residue of the resin composition layer 4 rather than circulating.

The etching apparatus of the present invention can be applied to an application for etching an insulating resin composition layer having an inorganic filler filled with a high content 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 a multi-layer build-up wiring board, a module board with built-in components, a flip chip package board, a motherboard for mounting a package board, and the like.

1 Circuit board 2 Insulation layer 3'Copper foil 3 Solder connection pad, connection pad 4 Resin composition layer 8 Metal mask 9 Copper foil 10 Etching liquid 11 Dip tank 12 Board 13 Transport roll pair 14 Input port 15 Storage tank 16 Etching liquid suction Port 17 Etching liquid supply tube 18 Etching liquid recovery port 19 Etching liquid recovery tube 19 ′ Etching liquid recovery tube 20 Etching unit 21 Etching liquid supply slit nozzle

Claims (3)

In an etching apparatus used for etching a resin composition layer containing an alkali-insoluble resin and an inorganic filler with an etching solution.
The etching apparatus has an etching unit for removing the resin composition layer.
An alkaline etching apparatus, wherein the etching unit has a dip tank in which an object to be processed having a resin composition layer is immersed in an etching solution, an etching solution supply pump, and an etching solution supply slit nozzle. The etching apparatus according to claim 1, wherein the content of the inorganic filler in the resin composition constituting the resin composition layer is 30 to 85% by mass. The etching apparatus according to claim 1 or 2, wherein the etching solution contains 5 to 50% by mass of an alkali metal hydroxide.

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