JP2002053684A - Etching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for etching a film in a short time anisotropically in the direction of its thickness and also affording an etching design uniformly in order. SOLUTION: This method for etching a resin film is characterized by involving irradiating the resin film with infrared rays prior to and/or during the etching operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for etching a resin film used for a wiring board.

[0002]

2. Description of the Related Art Conventionally, as a method of etching a resin such as polyimide, a method of wet etching using a solution containing hydrazine as a main component has been disclosed (JP-A-5-202206). An etching method using potassium oxide has been disclosed (Japanese Patent Laid-Open Publication No.
-301981).

However, in the usual wet etching method, there are materials that require a very long time for etching, and in some cases, materials that cannot be wet-etched. For example, it takes a very long time to wet etch a conventional polyimide, polyamide, or liquid crystal polymer manufactured by Polyplastics Co., Ltd., which is not practical. Even in a material that can be easily wet-etched, unevenness often occurs in the etching, and it has been particularly difficult to etch the entire surface in a uniform shape when etching a large area or performing continuous etching. In addition, generally, the finer the pattern, the longer the etching time and the problem that the variation in the etching increases. Furthermore, since the lateral direction and the thickness direction of the film to be etched are usually etched only to the same extent, it is difficult to etch a fine pattern as the film to be etched becomes thicker.

[0004]

SUMMARY OF THE INVENTION In view of the background of the prior art, the present invention enables anisotropic etching in a thickness direction of a film to be etched in a short time, and enables uniform etching. It is intended to provide an etching method capable of obtaining an etched shape.

[0005]

That is, the etching method of the present invention is characterized in that, when etching a resin film, infrared rays are irradiated before and / or during the etching. .

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Irradiation with infrared rays in the present invention
It can be performed before etching, during etching, or both. Irradiation before etching is effective mainly for modifying the surface of the film to be etched. By modifying the surface, the resin film can be etched anisotropically in the thickness direction, and the etching time can be reduced. It also leads to shortening. When the irradiation is performed during the etching, it is mainly effective in improving the etching efficiency, the etching can be performed in a short time, and the etching can be completed before the unnecessary etching of the resin film occurs in the lateral direction.
As a result, anisotropic etching can be performed in the thickness direction of the resin film. Furthermore, by using both irradiation methods together, both effects described above can be obtained.

The infrared ray used in the present invention is 0.8
Infrared rays such as near infrared (0.8 μm to 2 μm) and mid infrared (2 μm
5.6 μm) and far infrared (5.6 μm to 1 mm). Of these, the near infrared region of 0.8 μm
1.1 μm is preferred. As a light source for irradiating infrared rays, a halogen lamp in which an inert gas and a trace amount of a halogen substance are added to a sealing gas, a xenon lamp in which a pair of electrodes are provided opposite to each other in a quartz glass arc tube and xenon gas is sealed, and the like are used. Include, but are not limited to,
Anything can be used as long as it can emit infrared rays.

In the present invention, the time for irradiating infrared rays during etching is not particularly limited, but when irradiating before etching, a surface modification time suitable for each resin film is selected. When the irradiation is performed during the etching, it is preferable that the irradiation be performed intermittently, that is, it is preferable that the time of the infrared irradiation and the time of the non-infrared irradiation are alternately provided at the time of the etching. By performing infrared irradiation intermittently, etching can be performed more uniformly than by simply irradiating infrared light. In other words, although it is necessary to control the etching rate to improve the etching efficiency when irradiating infrared rays, intermittent irradiation can provide time for not irradiating infrared rays, so that the overall variation can be suppressed and as a result uniformity can be reduced. Can be improved. The method of irradiating the infrared ray or the case of not irradiating the infrared ray is optional, and it is optional depending on the type of the film to be etched. When such etching is performed a plurality of times, the type of infrared rays may be the same or may be changed each time. Further, it is optional to add another step such as washing in the middle.

As a specific example of intermittent etching,
For example, there is a method in which etching is performed for 1 to 10 minutes while irradiating infrared rays, then irradiation is stopped for 1 to 10 minutes, and etching is performed again for 1 to 10 minutes while irradiating infrared rays. In this case, the type of infrared rays may be constant, but may be different from each other.

The method of irradiating infrared rays may be such that the sample is directly irradiated with infrared rays or reflected by a mirror or the like.

According to the present invention, since the resin film can be etched in a short time, the working efficiency is remarkably improved, and it is very effective especially when the belt-shaped resin film is continuously etched. In addition, since etching can be performed uniformly without variation, a large-area resin film can be etched at a time, etching can be performed with uniform quality, and work efficiency can be improved. Furthermore, because it can be etched in a beautiful shape,
Not only is it advantageous in forming a fine pattern, but it also facilitates steps such as plating after etching. Being able to perform anisotropic etching is advantageous for forming fine patterns.

As the resin film etched by the present invention, for example, polyimide (for example, "Kapton" manufactured by Du Pont-Toray Co., Ltd., "Upilex" manufactured by Ube Industries, Ltd.) Co., Ltd., "Apical", polyamide (for example, "Mictron", manufactured by Toray Industries, Inc.), PPS (polyphenylene sulfide), PET (polyethylene terephthalate, such as "Lumirror", manufactured by Toray Industries, Inc.), liquid crystal polymer (for example, "Siveras" manufactured by Toray Industries, Inc., Polyplastics Co., Ltd.
"Vectra" manufactured by Nippon Petrochemical Co., Ltd., etc.) are used, but are not limited thereto. The above resins may be used alone, or two or more kinds may be blended or bonded. Further, various additives may be added to the resin film. Examples of such additives include, but are not limited to, fillers such as flame retardants, glass cloth, and the like. Among these, a resin film made of polyimide, polyamide or liquid crystal polymer is particularly preferably used.

[0013] The resin film may be cut into a suitable size or a strip. Further, the support may be attached to another material or may be adhered. In this case, as a support, metal, resin, glass, wood,
Paper, silicon wafers and the like can be used.

[0014] The thickness of the resin film is not particularly limited, and a thickness suitable for the use can be selected, but is preferably 500 µm or less, more preferably 100 µm or less.

As the etching of the present invention, a wet etching method mainly using an etching solution is preferably used. As such an etchant, an etchant suitable for the resin film to be etched is selected.

That is, a polyimide film or a polyamide film,
When etching a resin film such as a liquid crystal polymer,
Hydrazine-based solutions, such as ethylenediamine, ethanolamine, diethanolamine, aliphatic amine-based solutions such as hexamethylenediamine, such as benzylamine,
p-phenylenediamine, m-phenylenediamine, 3
-Acrylylenediamine, aromatic amine-based solutions such as 4-xylylenediamine, solutions containing alkali metal compounds such as potassium hydroxide and sodium hydroxide, and alkaline solutions in which these are used, and the like. Not limited. The above-mentioned etching solution may be either non-aqueous or aqueous, and an alcohol-based compound may be added to improve the uniformity of the solution. In some cases, a non-uniform combination may be used.

Specific examples of the combination of the etching liquids are preferably, but not limited to, the following examples.

(1) Combination of potassium hydroxide / water / amine / alcohol (for example, potassium hydroxide / water / ethylenediamine / ethylene glycol, potassium hydroxide /
Water / ethanolamine / ethylene glycol, potassium hydroxide / water / ethylenediamine / ethanol, potassium hydroxide / water / ethanolamine / ethanol, potassium hydroxide / water / ethylenediamine / glycerin, potassium hydroxide / water / ethanolamine / glycerin, Potassium hydroxide / water / benzylamine / ethylene glycol),
(2) Combinations of sodium hydroxide / water / amine / alcohol (for example, sodium hydroxide / water / ethylenediamine / ethylene glycol, sodium hydroxide / water / ethanolamine / ethylene glycol, sodium hydroxide / water / ethylenediamine / ethanol, water Sodium oxide / water / aeranolamine / ethanol, sodium hydroxide / water / ethylenediamine / glycerin, sodium hydroxide / water / ethanolamine / glycerin, sodium hydroxide / water / p-phenylenediamine / ethanol), (3) water Combinations of potassium oxide / water / amine (eg, potassium hydroxide / water / ethanolamine, potassium hydroxide / water / diethanolamine); (4) Combinations of sodium hydroxide / water / amine (eg, sodium hydroxide / water / ethanol) Ruamin, sodium hydroxide /
(5) combinations of potassium hydroxide / amine / alcohol (eg, potassium hydroxide / ethylenediamine / ethanol, potassium hydroxide / ethanolamine / ethanol, potassium hydroxide / ethylenediamine / ethylene glycol, potassium hydroxide / ethanol) Amine / ethylene glycol), (6) combinations of sodium hydroxide / amine / alcohol (eg, sodium hydroxide / ethylenediamine / ethanol, sodium hydroxide / ethanolamine / ethanol, sodium hydroxide / ethylenediamine / ethylene glycol, sodium hydroxide / (Ethanolamine / ethylene glycol).

The temperature of the etching solution largely depends on the properties of the film to be etched, and in particular, in the case of wet etching, it depends on the etching solution. Is 40
９０90 ° C. If the temperature is too high, the composition of the etching solution changes during the etching. Conversely, if the temperature is too low, the efficiency of the etching decreases, so that the above range is preferable.

The etching method of the present invention includes a method of immersing a film to be etched in an etchant, a method of spraying the etchant on the film to be etched, and the like. When immersing in an etching solution, a method of irradiating an ultrasonic wave in addition to the infrared irradiation of the present invention can be combined. A well-known vibrator is generally used for generating the ultrasonic waves. The frequency of these vibrators is not particularly limited, but is preferably 10 to 1000 kHz, more preferably 20 to 600 kHz. These vibrators may be used alone or in combination.

The ultrasonic wave may be irradiated in the thickness direction of the film to be etched, in the lateral direction of the etching film, or in an oblique direction, but more preferably in the thickness direction of the film to be etched. Better.

In the case of spraying an etching solution, a method is generally used in which a spray nozzle is attached to the tip of a blowout port and blown out by pressure. The shape of the spray nozzle is not particularly limited. For example, a mini mist, a round mist, an air injection nozzle, a descaling nozzle, a QC nozzle, a flat spray nozzle, a wide flat nozzle, an oblong nozzle, an oblique nozzle manufactured by Kyoritsu Gosei Co., Ltd. Flat nozzle, side spray nozzle, side spray nozzle, full cone nozzle, square nozzle, elliptical nozzle,
Spiral nozzles, hollow cone nozzles, cleaning nozzles, needle jet nozzles, and the like are used, but are not limited thereto. A single nozzle or a plurality of nozzles may be used, or different types of nozzles may be used in combination.

The pressure to be blown out also varies greatly depending on the type and thickness of the film to be etched.
Preferably, means for jetting at a pressure of 9000 to 10000000 Pa is employed. The jetting direction may be jetted from the thickness direction of the film to be etched, or from the lateral direction or oblique direction of the etching film, but more preferably the thickness direction of the film to be etched.

Next, a series of procedures of the etching method according to the present invention will be described, but the present invention is not limited to this method.

First, an etching mask (a copper mask, a stainless steel mask, a resist mask, etc.) is formed on the resin film. Examples of the mask forming method include a method of bonding the resin film to the resin film via an adhesive, a method of directly forming the mask on the resin film by sputtering or plating, and a method of adhering to the resin film. The mask may have a pattern formed in advance, or may be patterned after being formed on the resin film. Examples of the pattern formation of the mask include a method using a resist, a laser processing method, and the like.

After a patterned mask is formed on the resin film, etching is performed by supplying an appropriate etching solution from the mask side while irradiating infrared rays. Alternatively, first, an infrared ray is irradiated in advance, and then an etching solution is supplied from the mask side to perform etching. Examples of the method for supplying the etchant include a method in which the resin film is immersed in the etchant, a method using a spray, and the like.
Since etching is usually performed only from one side, it is preferable to protect the side of the resin film where the mask is not formed with an appropriate material. Examples of the protective material include copper, stainless steel, and resist.

The resin film processed by the etching method according to the present invention has through holes according to the etching pattern. By embedding a metal (such as copper or aluminum) for conduction in the through-hole, conduction on both sides of the resin film can be achieved. Further, by providing wiring on both surfaces of the resin film, a wiring board of two-layer wiring in which both surfaces are electrically connected can be obtained.

According to the present invention, since the hole for conducting can be finely formed in a good shape, the area which can be used for wiring increases accordingly, and as a result, a high-density wiring board can be formed. High-density wiring boards can be used in a wide range of applications from large substrates such as motherboards for personal computers to small substrates such as interposers for CSP (chip scale package).

[0029]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 and Comparative Example 1 A polyimide film "Kapton EN", "Upilex S", "Apical NPI", a polyamide film "Mictron", and a liquid crystal polymer film "Vectra CX" were cut into a size of 50 mm × 50 mm. . These resins were subjected to chromium sputtering, copper sputtering, and copper plating to form copper foils having a thickness of 8 μm on both surfaces. On both sides of this copper foil, a positive type photoresist “AZ P40” manufactured by Hoechst Co., Ltd.
"00" was applied by a spin coater and dried on a hot plate at 100 ° C. for 3 minutes. The dry film thickness was 10 μm.

Next, holes of 300 μmφ are formed every 2 mm.
One side was exposed at 300 mJ / cm ² with a g-line stepper using masks arranged in a grid of 4 × 24 pieces.
The Z400K developer was developed for 3 minutes using a developer diluted 5 times with water to form a 300 μmφ pattern suitable for the mask in a grid pattern.

Using the patterned photoresist as a copper etching mask and an aqueous solution of iron chloride at 40 ° C. as an etchant, a pressure of 196 was applied from a full cone nozzle (model number 1/4 KSFHS0665) manufactured by Kyoritsu Alloys Co., Ltd.
An aqueous solution of iron chloride was sprayed at 133 Pa to perform etching for 5 minutes.

After the etching of the copper, the photoresist is removed.
g, ethylene glycol 44 g, ethylene diamine 22
g and 68 g of water at 70 ° C., immersion, etching using a halogen lamp manufactured by Ushio Inc. as a light source while irradiating with infrared rays at 500 W until the holes penetrate. Time was observed.

For comparison, the same etching was performed without irradiating infrared rays.

The results are as shown in Table 1. Irradiation of infrared rays allowed any material from a thick resin to a thin resin to be etched in a short time. Without irradiation with infrared rays, "Upilex S", "Mictron", and "Vectra CX" could not be etched, and "Kapton EN" and "Apical NPI" also required a long time for etching.

[0036]

[Table 1]

Example 2 and Comparative Example 2 A roll-shaped sample having a width of 504 mm of polyimide film "Kapton EN", "Upilex S", "Apical NPI", polyamide film "Mictron", liquid crystal polymer film "Vectra CX" was used. First, a copper mask was formed in the same manner as in Example 1.

After forming the copper mask, 33 g of potassium hydroxide,
22 g of ethylene glycol, 11 g of ethylene diamine,
Using an etching solution composed of 66 g of water at 70 ° C., immersing while irradiating ultrasonic waves at 38 kHz from the copper mask side, a near-infrared irradiation device LA-100I manufactured by Hayashi Watch Industry Co., Ltd.
Using R, etching is performed while irradiating infrared rays at 200 W, the time until the hole penetrates and the etching shape,
The variation in etching was observed.

For comparison, the same etching was performed without irradiating infrared rays.

The etching time in Example 2 and Comparative Example 2 was 504 mm × 504 m, which is the size of the mask.
Assuming that m is one unit, the etching of one unit is completed and the etching of the next unit is continued, and the etching is continuously performed for 20 hours. The average of the etching time required for one unit is defined as the etching time.

The results are as shown in Table 2. By irradiating infrared rays, any material from a thick resin to a thin resin could be uniformly etched in a short time in a good shape.

However, when infrared rays are not radiated, etching cannot be performed with "Upilex S", "Mictron" or "Vectra CX", and "Kapton EN" or "Apical N" cannot be used.
"PI" also had a bad shape, and there were many variations depending on the location.

[0043]

[Table 2]

Example 3 A metal royal film manufactured by Toyo Metallizing Co., Ltd. (a material in which a 25 μm thick polyimide film “Kapton EN” and an 8 μm thick copper film formed on both sides) was cut into a size of 5 cm square. . Copper etching was performed in the same manner as in Example 1 except that a mask constituted of a circular pattern of 40 to 150 μmφ was used.

After the completion of the copper etching, the photoresist is removed.
g, ethylene glycol 22 g, ethylene diamine 11
g and 34 g of water at 60 ° C. using a hollow cone nozzle (model number KSC005) manufactured by Kyoritsu Gosei Seisakusho Co., Ltd. at a pressure of 490332.5 Pa.
Then, an etching solution was sprayed in the thickness direction of the film, and etching was performed while changing the time while irradiating infrared rays at 200 W using INFRASTEIN manufactured by NGK Insulators, Ltd.

After completion of the polyimide etching, copper was removed using an aqueous solution of iron chloride, and the shape of the etched polyimide was observed. The results are as shown in Table 3, and good etching was performed in a short time. In addition, “anisotropy in the thickness direction with respect to the horizontal direction” indicates a ratio of how much the film is etched in the horizontal direction as compared with the thickness of the etched film.

In Table 3, for example, the mask setting pattern diameter is 15
In the case of 0 μm, the difference between the polyimide pattern diameter on the resist side and the polyimide pattern diameter on the bottom side is 30 μm. In the case of the horizontal direction, the etching is performed not in one direction but in two directions, so that the etching is 15 μm in the horizontal direction. Since the thickness of the etched polyimide film is 25 μm, in this case, 25 ÷ 15 = 1.7 (times) becomes anisotropic.

Comparative Example 3 Example 3 was carried out in the same manner as in Example 3 except that the polyimide was not irradiated with infrared rays during etching. Example 1
It took a longer time for etching than that of, and the etching was distorted and had many variations.

[0049]

[Table 3]

Example 4 A metal royal film manufactured by Toyo Metallizing Co., Ltd. (a material in which a 50 μm-thick polyimide film “Kapton EN” and an 8 μm-thick copper film formed on both surfaces) was used as a copper etching solution and chloride was used. Example 3 except that an aqueous copper solution was used.
, And copper was etched.

After the completion of the copper etching, the photoresist is removed. This time, using copper as a mask, potassium hydroxide 33 is removed.
g, monoethanolamine 22 g, ethylenediamine 1
Using an etching solution for polyimide composed of 1 g and 34 g of water at 50 ° C., immersing in an etching solution while irradiating ultrasonic waves at 950 kHz from the copper mask side, and using a xenon lamp manufactured by Ushio Inc. at 300 W Etching was performed while changing the time while irradiating infrared rays.

After the completion of the polyimide etching, copper was removed using an aqueous copper chloride solution, and the shape of the etched polyimide was observed. The results are as shown in Table 4, and good etching was performed in a short time.

Comparative Example 4 Example 4 was carried out in the same manner as in Example 4 except that no infrared rays were irradiated during the etching of the polyimide. Example 2
It took a longer time for etching than that of, and the etching was distorted and had many variations.

[0054]

[Table 4]

Example 5 Chromium and copper were sputtered on one side of a 25 μm thick polyamide film “MICRON” in this order, and then 8 μm thick copper films were formed on both sides by electrolytic plating. Using this material, copper was etched in the same manner as in Example 3.

After the etching of the copper, the photoresist is removed. This time, using copper as a mask, potassium hydroxide 10
g, 43 g of monoethanolamine, 1 ethylenediamine
Using an etching solution for polyamide consisting of 1 g and 36 g of water at 80 ° C., immersing in an etching solution while irradiating ultrasonic waves at 100 kHz from the copper mask side, and using a xenon lamp manufactured by Ushio Inc. at 220 W Etching was performed while changing the time while irradiating infrared rays.

After the completion of the polyamide etching, copper was removed using an aqueous iron chloride solution, and the shape of the etched polyamide was observed. The results are as shown in Table 5, and good etching was performed in a short time.

Comparative Example 5 The procedure of Example 5 was repeated, except that no infrared rays were irradiated during the etching of the polyamide. Example 3
A longer time was required for etching than in the case of and etching could not be performed.

[0059]

[Table 5]

Example 6 Liquid crystal polymer film "VECTRA CX" having a thickness of 50 μm
Was sputtered with chromium and copper in this order, and then a copper film having a thickness of 8 μm was formed on both surfaces by electrolytic plating. Using this material, copper was etched in the same manner as in Example 3.

After the completion of the copper etching, the photoresist is removed. This time, using copper as a mask, potassium hydroxide 20 is removed.
g, 43 g of monoethanolamine, 1 ethylenediamine
Using an etchant for liquid crystal polymer composed of 1 g and 26 g of water at 80 ° C., immersing in an etchant while irradiating ultrasonic waves at 200 kHz from the copper mask side, using a xenon lamp manufactured by Ushio Inc. Etching was performed while changing the time while irradiating infrared rays.

After the completion of the liquid crystal polymer etching, copper was removed using an aqueous iron chloride solution, and the shape of the etched liquid crystal polymer was observed. The results are as shown in Table 6, and good etching was performed in a short time.

Comparative Example 6 The procedure of Example 6 was repeated, except that no infrared rays were irradiated during the etching of the liquid crystal polymer. A longer time was required for etching than in Example 4, and the etching could not be performed.

[0064]

[Table 6]

Example 7 The sample obtained by etching copper in Example 3 was used.
After the copper etching was completed, the photoresist was removed. Then, using the light source used in Example 1, infrared rays were irradiated from the patterned copper side for 2 minutes. After irradiating the infrared rays, this time, using copper as a mask, the polyimide etching solution used in Example 1 was used at 60 ° C., and ultrasonic waves were irradiated from the copper mask side at 200 kHz to be immersed in the etching solution.
Using the light source used in the above, etching was performed while changing the time while irradiating infrared rays.

After completion of the polyimide etching, copper was removed using an aqueous solution of iron chloride, and the shape of the etched polyimide was observed. The results are as shown in Table 7, and good etching was performed in a short time.

Example 8 The sample obtained by etching copper in Example 5 was used.
After the copper etching was completed, the photoresist was removed. Then, using the light source used in Example 1, infrared irradiation was performed for 2 minutes from the patterned copper side. After irradiating the infrared rays, this time, using copper as a mask, the etching solution for polyamide used in Example 5 was used at 80 ° C., and ultrasonic waves were irradiated from the copper mask side at 38 kHz to be immersed in the etching solution. Etching was performed using an incompatible light source while changing the time while irradiating infrared rays.

After the polyamide etching was completed, copper was removed using an aqueous solution of iron chloride, and the shape of the etched polyamide was observed. The results are as shown in Table 7, and good etching was performed in a short time.

[0069]

[Table 7]

Example 9 The sample obtained by etching copper in Example 3 was used.
After the etching of copper, the photoresist is removed, and this time using copper as a mask, an etching solution for polyimide composed of 33 g of potassium hydroxide, 22 g of ethylene glycol, 11 g of ethylenediamine, and 34 g of water is used at 70 ° C.
Hollow cone nozzle (KSC)
From 005), an etching solution was sprayed in the thickness direction of the film at a pressure of 490332.5 Pa, and etching was performed for 120 seconds while irradiating infrared light in the thickness direction using the light source used in Example 1.

Next, the same etching was performed for 120 seconds by stopping the irradiation of the infrared rays.

After completion of the polyimide etching, copper was removed using an aqueous solution of iron chloride, and the etched polyimide was observed. The results are as shown in Table 8, and good etching was performed in a short time.

Example 10 In Example 9, the polyimide was etched in the same manner as in Example 9 except that the polyimide was etched for 120 seconds without irradiating infrared rays, and then etched for 120 seconds while irradiating infrared rays. To etch the polyimide.

After completion of the polyimide etching, copper was removed using an aqueous solution of iron chloride, and the shape of the etched polyimide was observed. The results are as shown in Table 8, and good etching was performed in a short time.

[0075]

[Table 8]

Example 11 The sample obtained by etching copper in Example 5 was used.
After the etching of copper, the photoresist is removed, and this time using copper as a mask, 33 g of potassium hydroxide, 22 g of monoethanolamine, 11 g of ethylenediamine, and 34 g of water.
Using an etching solution for polyamide composed of at 70 ° C., immersing in an etching solution while irradiating ultrasonic waves from the copper mask side at 100 kHz, and irradiating infrared rays in the thickness direction using the light source used in Example 2. While etching for 80 seconds.

Next, the same etching was performed for 80 seconds by stopping the irradiation of the infrared rays. After that, the same etching was performed for 80 seconds while performing infrared irradiation again. After the completion of the polyamide etching, copper was removed using an aqueous solution of copper chloride, and the shape of the etched polyamide was observed. Table 9 shows the results.
And good etching was achieved in a short time.

Example 12 In Example 11, when the polyamide was etched, etching was first performed for 80 seconds without irradiating infrared rays, followed by etching for 80 seconds while irradiating infrared rays, and then again for 80 seconds without irradiating infrared rays. The polyamide was etched in the same manner as in Example 11 except that etching was performed. After the end of the polyamide etching, copper was removed using an aqueous solution of iron chloride, and the shape of the etched polyamide was observed. The results are as shown in Table 9, and good etching was performed in a short time.

[0079]

[Table 9]

[0080]

According to the present invention, the resin film used for the wiring board can be anisotropically etched in the thickness direction in a short time.

Claims (4)

[Claims] 1. An etching method, comprising: irradiating an infrared ray at least one of before and during etching when etching a resin film. 2. The etching method according to claim 1, wherein the resin film is at least one selected from the group consisting of polyimide, polyamide, polyphenylene sulfide, polyethylene terephthalate, and liquid crystal polymer. 3. The etching method according to claim 1, wherein the wavelength of the infrared ray is 0.8 μm to 1 mm. 4. The etching method according to claim 1, wherein the method of irradiating infrared rays during the etching is a method of performing irradiation intermittently.