JPH07235743A - Fluororesin formation for abrasion working and manufacture of worked fluororesin board - Google Patents

Abstract

PURPOSE:To facilitate abrasion working and to raise mechanical strength by adding a specific amount of resin having an absorption wavelength in an ultraviolet range to fluororesin. CONSTITUTION:The fluororesin formation is composed of resin having an absorption wavelength in an ultraviolet range and fluorine resin. 1-125 pts.wt. of resin having an absorption wavelength in the ultraviolet range is added to 100 pts.wt. of fluororesin. Besides, it contains fluororesin dispersing solution and resin solution or dispersing solution having an absorption wavelength in the ultraviolet range. The resin having an absorption wavelength in the ultraviolet range is used as an abrasion accelerator, and can be used without any particular restriction whether it is thermoplastic or thermosetting, if it has an absorption wavelength in the ultraviolet range. The use of this fluororesin formation for abrasion working makes easy and efficient fine working by abrasion possible, and it also becomes possible for an excellent mechanical strength characteristic to be fully exhibited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluororesin composition suitable for ablation processing and a method for producing a processed fluororesin substrate.

[0002]

2. Description of the Related Art With the development of electronic devices in recent years, the demand for miniaturization and high density of circuit boards has led to multilayer wiring boards and wiring pitches becoming finer and finer. Therefore, it is necessary to form a high density of fine through-holes (through holes) having a diameter of 100 μm or less for establishing electrical continuity between layers, and further to provide pit holes and grooves that do not completely penetrate the substrate. It is also required to form a conductive path to the intermediate layer and to have additional functions such as device holes and alignment. Such fine and complicated shapes cannot be dealt with by machining.Therefore, there is a perforation method by ablation, which irradiates a high energy beam such as an ultraviolet laser beam with energy control and irradiates it, and decomposes it by absorbing the ultraviolet rays of the insulating material. It is being used.

Further, the circuit board is also required to have a high speed response of an electric signal, and the impedance characteristic of the circuit board is controlled by the wiring design and the constitution of the conductive material and the insulating material to avoid crosstalk of the electric signal. Is needed. In particular, in circuit boards in the high-speed field, fluorocarbon resin with a low relative dielectric constant has been used as an insulating material, and it is formed as a multilayer circuit board by stacking multiple layers of sheet fluorocarbon resin and conductive wiring. . Further, for conduction between the layers, a through hole for forming a conduction path is formed in the fluororesin by machining such as punching, as used in the conventional method for forming a circuit board, and an inner wall of the through hole is formed. By attaching a conductive material to the, or filling the through hole with a conductive material,
A method of electrically connecting the wirings at both ends of the opening of the through hole is adopted.

[0004]

There is a strong demand for miniaturization, high density, and high functionality in the above-mentioned circuit boards in the high-speed field, and in order to meet these demands, lasers that enable complex and fine processing Although the application of the processing method has been desired, the fluororesin substrate from which the low-dielectric circuit board is obtained does not absorb ultraviolet rays, and the perforation method by ablation cannot be used.

On the other hand, Japanese Patent Laid-Open No. 4-120173 proposes a method of promoting ablation by mixing a dye that absorbs ultraviolet rays with a fluororesin. However, the dye contained in the above-mentioned known fluororesin composition is decomposed at the firing temperature at the time of molding the fluororesin, and the function thereof cannot be sufficiently exhibited. In addition, the mechanical strength, heat resistance, dimensional stability and the like of the substrate used are impaired.

Further, Japanese Patent Publication No. 3-502075 proposes a method of laser-perforating a fluoropolymer material, and the fluoropolymer is provided with fine glass, silica, titanium dioxide, carbon fibers, fine balloons, and Kevlar. (Kevlar)
And the like are disclosed. This fluoropolymer composition may interfere with the low dielectric properties of the substrate.

[0007]

An object of the present invention is to provide a fluororesin composition suitable for ablation processing. Another object of the present invention is to provide a method for producing a processed fluororesin substrate which can be subjected to complicated fine processing and is excellent in mechanical strength.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to solve the above-mentioned problems in the prior art, and as a result, fluororesins and resins having an absorption wavelength in the ultraviolet region, particularly resins having excellent heat resistance. It has been found that a fluorine-based resin film formed from a composition containing a is easily ablated and has excellent mechanical strength. Further, they have found that the efficiency of the ablation process can be significantly improved by controlling the crystallinity of the fluororesin.

The present invention has been completed based on the above findings and has the following gist. (1) A fluororesin composition for ablation processing, which comprises a resin having an absorption wavelength in the ultraviolet region and a fluororesin. (2) The fluororesin composition for ablation processing according to (1), wherein the resin having an absorption wavelength in the ultraviolet region is contained in an amount of 1 to 125 parts by weight with respect to 100 parts by weight of the fluororesin. (3) The fluororesin composition for ablation processing according to (1), which comprises a fluororesin dispersion and a resin solution or dispersion having an absorption wavelength in the ultraviolet region. (4) The fluororesin composition for ablation processing according to (1), which comprises a fluororesin powder and a resin powder having an absorption wavelength in the ultraviolet region. (5) The fluororesin composition for ablation processing according to (1), which comprises a film-shaped fluororesin containing a resin having an absorption wavelength in the ultraviolet region. (6) The fluororesin composition for ablation processing according to any one of (1) to (5), wherein the resin having an absorption wavelength in the ultraviolet region is a polyimide resin. (7) The step of forming a fluororesin-containing film with the fluororesin composition according to the above (1) or (2), a step of irradiating the fluororesin-containing film with an ultraviolet laser, and the ultraviolet ray if necessary. A method of manufacturing an ablation-processed fluororesin substrate, which comprises a step of curing a fluororesin-containing film irradiated with a laser. (8) The fluororesin-containing film is formed by coating the support with the fluororesin composition according to (3) and then volatilizing the solvent or the dispersion medium (7) of the processed fluororesin substrate. Production method. (9) The method for producing a fluororesin substrate according to (7), wherein the fluororesin-containing film is formed by heating and pressing the fluororesin composition according to (4). (10) The method for producing a fluororesin substrate according to (7), wherein the fluororesin-containing film is formed from the fluororesin composition according to (5). (11) The crystallinity of the fluororesin in the fluororesin-containing film is 70% or more as measured by a wide-angle X-ray diffraction method, according to any one of (7) to (10). Manufacturing method of fluororesin substrate.

The present invention will be described in more detail below. The fluororesin composition of the present invention is characterized in that the fluororesin contains a resin having an absorption wavelength in the ultraviolet region.
Examples of the fluororesin include polytetrafluoroethylene, trichlorofluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polyvinylidene fluorolide, polyvinyl fluorolide, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene. -Ethylene copolymers, chlorotrifluoroethylene-ethylene copolymers and the like can be mentioned, and they can be used as one kind or a mixture of two or more kinds. The fluororesin is used in the form of powder or dispersion.

The dispersion medium used in the above-mentioned fluororesin dispersion liquid is not particularly limited as long as it can disperse the fluororesin, and examples thereof include water, alcohols, glycols, ethers, ketones, and amides. A system, an organic solvent such as an aromatic hydrocarbon system is used, and preferably, one capable of dissolving the resin is selected in order to uniformly mix the resin having an absorption wavelength in the ultraviolet region used as an ablation accelerator. .

The resin having an absorption wavelength in the ultraviolet region is used as an ablation accelerator, and is not particularly limited as long as it has an absorption wavelength in the ultraviolet region and can be used regardless of thermoplasticity or thermosetting property. . For example, polyamide-based resin, polyacrylic-based resin, polyurethane-based resin, polyester-based resin, polyimide-based resin and the like having an aromatic ring can be mentioned, and one kind or a mixture of two or more kinds thereof can be used. Among them, it is preferable to use a polyamide resin, a polyimide resin, or the like, which has excellent heat resistance, and a polyimide resin is particularly preferable because it does not impair mechanical properties and the like even after being mixed with a fluororesin to form a film and baking and curing at a high temperature. As the polyimide resin, thermoplastic polyimide such as polyetherimide, polyamideimide, polyesterimide, polyimide synthesized from maleic anhydride and aromatic diamine such as diaminodiphenylmethane, thermosetting of polyaminobismaleimide, etc. Examples include polyimide. In addition, tetracarboxylic dianhydrides such as pyromellitic dianhydride, butanetetracarboxylic acid, and biphenyltetracarboxylic dianhydride, and diamines such as 4,4′-diaminodiphenyl ether, diaminodiphenylmethane, and paraphenylenediamine. A polyimide precursor such as a polyamic acid obtained by the reaction and other oligomers can also be preferably used.

In the present invention, it is preferable to use a polyimide precursor which is soluble in an organic solvent and is easy to form a film. This polyimide precursor is dehydrated and condensed by heat treatment at a high temperature of 300 ° C. or higher to be ring-closed and converted into polyimide.

The resin having an absorption wavelength in the ultraviolet region is used in the form of powder, solution or dispersion. When used as a solution or dispersion, as the solvent or dispersion medium,
It is not particularly limited as long as it can dissolve or disperse the resin, and for example, water or alcohol-based, glycol-based, ether-based, ketone-based, amide-based, aromatic hydrocarbon-based organic solvents can be used, Above all, it is preferable to use, for example, a water-based or alcohol-based dispersion medium that is compatible with the dispersion medium of the fluororesin dispersion liquid that does not hinder uniform mixing when mixed with the fluororesin.

The fluororesin composition of the present invention is prepared, for example, by the following method. A method of mixing and dispersing an aqueous dispersion of a fluororesin, a resin solution having an absorption wavelength in the ultraviolet region, a resin solution modified to be water-soluble by chlorination or the like, or a dispersion in which the resin is dispersed in water. A method of mixing and dispersing an alcohol-based or amide-based organic solvent-based fluororesin dispersion and a resin solution or dispersion having an absorption wavelength in the ultraviolet region. At that time, as the medium for the resin having an absorption wavelength in the ultraviolet region, it is preferable to use an organic solvent compatible with the medium for the fluororesin dispersion liquid. A method of dry blending a fluororesin powder and a resin powder having an absorption wavelength in the ultraviolet region. A method of incorporating a resin solution having an absorption wavelength in the ultraviolet region into a fluororesin formed in advance. This method is performed, for example, by making the fluororesin porous, impregnating it with a resin solution having an absorption wavelength in the ultraviolet region, and filling the pores of the fluororesin with the resin.

In the above-mentioned preparation method, in order to uniformly disperse and dissolve the fluororesin and the resin having an absorption wavelength in the ultraviolet region in the medium, a surfactant having a long-chain alkyl group or the like may be added. Good.

In the above-mentioned fluororesin composition, the mixing ratio of the fluororesin and the resin having an absorption wavelength in the ultraviolet region is 100 wt. The amount is 1 to 125 parts by weight, preferably 3 to 60 parts by weight, and particularly preferably 5 to 30 parts by weight. The higher the mixing ratio of the resin having the absorption wavelength in the ultraviolet region, the better the ablation processability. Therefore, if the mixing ratio is less than 1 part by weight, the processing speed is slow and the practicality is poor, while it exceeds 125 parts by weight. On the contrary, there is a possibility that the low dielectric property of the fluororesin may not be sufficiently exhibited, or the mechanical strength may be adversely affected.

The above-mentioned fluororesin composition and therefore the fluororesin film do not impair ablation processability, do not impair the low dielectric constant of the fluororesin film, and do not reduce the mechanical strength. Fillers such as glass, silica, ceramics, carbon fibers, Kevlar, etc. may be mixed in amounts within the range. The mixing ratio of this filler is 20 parts by weight or less, preferably 5 parts by weight or less, relative to 100 parts by weight of the fluororesin.

The method for producing a fluororesin substrate of the present invention is
A step of forming a fluororesin film from the fluororesin composition, a step of irradiating the fluororesin film with an ultraviolet laser, and a step of curing the fluororesin film irradiated with the ultraviolet laser. Characterize.

The above-mentioned fluorine-based resin film can be formed by using the above-mentioned fluorine-based resin composition, for example, by the following method. A method of casting a liquid fluororesin composition on a support such as a metal plate (SUS plate, copper plate, etc.), a ceramic plate, a silicone wafer, etc. and drying it. A method in which a fluororesin composition composed of a mixed powder is heat-compression-molded and then thinly cut by a known method. A porous fluororesin film produced according to the above method is formed into a film, and a solution or dispersion of a resin having an absorption wavelength in the ultraviolet region is impregnated into the pores, followed by heating and drying the solvent or dispersion. This is done by removing the medium.

In the present invention, the thickness of the fluororesin film is usually 1 to 1000 μm, preferably 10 to 100 μm. When this fluororesin film is less than 1 μm,
The above-mentioned fluorine-based resin film cannot function mechanically as an insulating layer and has a practically sufficient function. On the other hand, if it exceeds 1000 μm, it takes a long time for ablation processing, and the obtained pore shape is 100 μm or less. Hard to get.

The support used for forming the fluororesin film is used as it is when mechanical strength or conductivity is required in the ablation process described later. .

The degree of crystallinity of the fluororesin in the fluororesin film by the wide-angle X-ray diffraction method is 70% or more, especially 80.
% Or more is preferable. When the crystallinity is 70% or more, the processing efficiency in ablation processing is good.

When measuring the crystallinity of a fluororesin by the above wide-angle X-ray diffraction method for a fluororesin composition using a crystalline heat-resistant resin as an ablation accelerator, the crystalline heat-resistant resin is used. It is necessary to evaluate the crystallinity of the fluororesin alone as a parameter by subtracting the influence of.

The fluororesin film is ablated by irradiating it with an ultraviolet laser in order to form through holes, pit holes or grooves at desired positions. The irradiation conditions of this ultraviolet laser are not particularly limited, but are usually ArF (193 nm), KrF (248 n).
m), XeCl (308 nm), XeCl (351n
Excimer laser light such as m) is used. For example,
The excimer laser light having an energy density of 0.005 to 10 J / cm ² is applied directly or directly to a patterning mask having a desired shape at a repetitive pulse rate of 1 to 3000 Hz through an optical system having a reduction ratio of 0.1 to 20 times. By irradiating the above-mentioned fluorocarbon resin substrate for a predetermined time, a fine through hole (through hole) having a diameter of 100 μm or less
Is formed at a high density of, for example, 400 holes / cm ² , and by further controlling the irradiation energy amount of the above-mentioned ultraviolet laser, fine processing such as providing pit holes or grooves that do not completely penetrate the substrate is performed. You can

[0026] In the irradiation of the ultraviolet laser, the energy density, for example, 0.1 J / cm ² or more, preferably as high as 0.5 J / cm ² or more, the reduction magnification of the optical system, e.g. 3 times or more, preferably 5 times or more, and the number of repetitive pulses is, for example, 50H.
When it is set to be equal to or higher than z, preferably equal to or higher than 200 Hz, the ablation processing efficiency is improved, which is preferable.

The fluororesin film finely processed by the above-mentioned ablation process is heated at a temperature not lower than the melting point of the fluororesin to melt the fluororesin by using a pressure if necessary, and then predetermined. The fluororesin film is cured by cooling at the cooling rate. This curing treatment improves the mechanical strength of the fluororesin film.

For the through holes formed by the ablation process, electrolytic plating, electroless plating, metal vapor deposition or the like is used, or a conductive resin paste or molten metal is used to form a metal on the inner wall of the through holes. Can be attached or the whole hole can be filled with metal to form an electrical conduction path in the thickness direction of the circuit board. Further, the metal portion may be raised further outward than the opening of the hole to form a bump shape having a mushroom shape, a rivet shape, or the like, and used as an electrical connection terminal with external wiring. By forming the bump-shaped electrodes (terminals), electrical connection can be surely made, which is preferable.

In addition, the pit holes and grooves which do not penetrate are formed with a conductive path to the intermediate layer by using the same method as described above, or are used as device holes for loading external parts, and are used as external wiring terminals. It is used for positioning such as for electrical connection and loading of external parts.

Since the fluororesin substrate of the present invention has a wiring pitch in which electric conduction paths are formed with high density, the circuit board can be downsized and the density can be increased, and high-speed response of electric signals can be achieved. It will be possible.

[0031]

[Functions / Effects] According to the fluororesin composition for ablation processing of the present invention, since the fluororesin contains a resin having an absorption wavelength in the ultraviolet region, it is possible to perform microfabrication easily and efficiently by ablation processing. In addition, the mechanical strength characteristics of the fluorinated resin after firing and curing can be sufficiently exhibited. Further, according to the method for producing a processed fluororesin substrate of the present invention, since the fluororesin film is formed from the above fluororesin composition, the ablation is performed by irradiating the fluororesin film with an ultraviolet laser. Processing becomes possible. Further, when the crystallinity of the fluororesin in the fluororesin film is set to 70% or more, the crystal part of the fluororesin is easily broken by the irradiation of the ultraviolet laser. In addition, since the electric conduction paths can be formed at a high density on the fluororesin substrate by processing by the method of the present invention, the circuit board can be downsized, the density can be increased, and a high-speed response of electric signals can be achieved. .

[0032]

EXAMPLES Examples will be shown below to more specifically describe the present invention. However, the present invention is not limited to these examples. In the examples, the crystallinity of the fluororesin is a value measured by the wide-angle X-ray diffraction method. Example 1 A polyimide precursor solution obtained by polymerizing pyromellitic dianhydride and 4,4′-diaminodiphenyl ether in N-methyl-2-pyrrolidone at an equimolar ratio (solid content 2
0%) 100 g and polytetrafluoroethylene powder [KTL-8N manufactured by Kitamura Co., Ltd.] dispersed in N-methyl-2-pyrrolidone (solid content 25
% By weight), and the mixed solution is coated on a copper plate, and the mixture is applied at 70 ° C. for 1 hour, 100 ° C. for 1 hour, and 160 ° C. for 1 hour.
And the coating is dried at 300 ° C for 1 hour,
This was baked and cured by treating at 400 ° C. for 30 minutes to obtain a 20 μm thick fluororesin coating film. The crystallinity of polytetrafluoroethylene in this resin coating film was 70%. 0.25 J / cm ^{2 on} this coating
A KrF (248 nm) excimer laser beam having an energy density of 100 μm diameter that reaches a copper plate by irradiating it with a mask at a repetition pulse rate of 250 Hz for 1 second through an optical system with a reduction ratio of 5 times. Through-holes were formed at a pitch of 300 μm to obtain a substrate including a fluororesin layer and a copper layer in which fine through-holes were formed.

Example 2 100 g of a polyimide precursor solution (solid content 30%) obtained by polymerizing butanetetracarboxylic acid and diaminodiphenylmethane in triethylene glycol at an equimolar ratio was treated at 150 ° C. and then treated with ammonia water. 10 ml was added, and this was mixed with 500 g of a dispersion (solid content 40% by weight) in which a tetrafluoroethylene-hexafluoropropylene copolymer dispersion (Neotron ND-1 manufactured by Daikin Co., Ltd.) was dispersed in water, and this mixed liquid Is applied on a SUS plate for 30 minutes at 70 ° C and 1 at 100 ° C.
It was dried for an hour to obtain a fluororesin coating film having a thickness of 35 μm. The crystallinity of the tetrafluoroethylene-hexafluoropropylene copolymer in this resin coating film was 85%. A KrF (248 nm) excimer laser beam having an energy density of 0.15 J / cm ² was applied to this coating film through an optical system with a reduction ratio of 3 times, and a repetition pulse number of 100 Hz.
By irradiating with a mask for 0.1 second,
Pit holes with a diameter of 1 mm and a depth of 10 μm were formed at a pitch of 5 mm. Then, this coating film at 300 ° C. for 30 minutes,
This was baked and cured by treatment at 400 ° C. for 30 minutes to obtain a substrate composed of a fluorine-based resin layer having a concave shape and a SUS layer.

Example 3 Polyimide precursor solution (solid content 20%) 5 obtained by polymerizing biphenyltetracarboxylic dianhydride and paraphenylenediamine in equimolar ratio in dimethylacetamide 5
To 0 g, 30 g of triethylamine is added and mixed well, and 70 g of water is added to make an aqueous solution. This aqueous solution was mixed with 500 g of dispersion (solid content 40% by weight) in which polytetrafluoroethylene dispersion (XAD-934-AIF manufactured by DuPont) was dispersed in water, and this mixed solution was applied onto a copper plate. 1 hour at 70 ℃, 1
Dry at 50 ℃ for 30 minutes and 130 ℃ for 30 minutes
A m-thick fluorine resin coating film was obtained. The crystallinity of polytetrafluoroethylene in this resin coating film was 80%. This coating film was irradiated with XeCl (308 nm) excimer laser light having an energy density of 1.5 J / cm ² through an optical system having a reduction ratio of 5 times and a repetition pulse number of 200 Hz.
By irradiating with a mask for 0.2 seconds,
In addition, 100 through holes with a diameter of 50 μm that reach the copper plate
It was formed with a μm pitch. Then, this coating film was treated at 300 ° C. for 1 hour and at 400 ° C. for 30 minutes to be baked and cured to obtain a substrate including a fluororesin layer having fine through holes and a copper layer.

Example 4 100 g of polyimide powder obtained by polymerizing pyromellitic dianhydride and 4,4'-diaminodiphenyl ether at an equimolar ratio, polytetrafluoroethylene powder (trade name: Polyflon M-31, manufactured by Daikin Co., Ltd.) ) 100 g and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer powder (MP-10 manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) 100 g were mixed by a ball mill, and the mixed powder was formed into a cylindrical mold having an inner shape of 30 mmφ × 50 mmL. After filling, the mixture was heated and pressurized at 380 ° C. and 300 kg / cm ² for 5 hours to be fired and molded. Cut this block body to 1
A fluororesin film having a thickness of 50 μm was obtained. The crystallinity of polytetrafluoroethylene in this resin film was 65%, and the crystallinity of the tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer was 65%.
This coating has a Kr of energy density of 0.25 J / cm ^2.
By irradiating the F (248 nm) excimer laser light through the optical system with the reduction magnification of 5 times at the repetitive pulse number of 250 Hz for 2 seconds using the mask, the fine through holes of 200 μm diameter penetrating this are 400 μm pitch. Formed by.

Example 5 A porous membrane (20 μm thick, open area ratio 15%) obtained by cutting and stretching a block of polytetrafluoroethylene (Polyflon F-104 manufactured by Daikin Co., Ltd.) was used as a bismaleimide.
Methyl ethyl ketone solution of triazine resin (solid content 10
%) For 1 hour and treated at 100 ° C. for 1 hour, 200 ° C. for 30 minutes, and 250 ° C. for 30 minutes to obtain a fluororesin film. The crystallinity of polytetrafluoroethylene in this resin film was 70%. 0.20 on this coating
KrF (248 nm) excimer laser light with an energy density of J / cm ² is passed through an optical system with a reduction ratio of 5 times.
Irradiation was performed at a repetition pulse rate of 250 Hz for 1 second using a mask to form fine through holes having a diameter of 100 μm and a pitch of 400 μm.

Comparative Example Dispersion (solid content 40%) in which polytetrafluoroethylene was dispersed in water was applied on a copper plate to 70 ° C.
It was dried for 1 hour at 100 ° C. for 30 minutes and at 130 ° C. for 30 minutes to obtain a fluororesin coating film having a thickness of 20 μm. KrF (248 nm) with an energy density of 1 J / cm ² was applied to this coating film.
Excimer laser light is passed through an optical system with a reduction ratio of 3 times with a repetitive pulse rate of 250 Hz and a mask 1
Irradiate for 0 seconds. Although the surface of the coating film was blackened and burnt, it was not possible to form through holes reaching the copper plate.

[0038]

EFFECTS OF THE INVENTION According to the fluororesin composition for ablation processing of the present invention, the resin that absorbs ultraviolet rays is not decomposed even by the high temperature at which the fluororesin is baked, and the filler is not contained. Therefore, the fluororesin film formed from this composition is excellent in mechanical strength. Further, since a resin having an absorption wavelength in the ultraviolet region is uniformly mixed in the fluorine-based resin film formed from the fluorine-based resin composition, it is possible to perform fine ablation by irradiating the fluorine-based resin film with ultraviolet rays. Processing becomes possible.

Further, according to the method for producing a fluororesin substrate of the present invention, by irradiating the fluororesin film with an ultraviolet laser, fine through holes can be formed at a high density, or the fluororesin film can be formed. Pit holes and grooves that have not completely penetrated and conductive paths to the intermediate layer can be easily ablated. Moreover, since the crystallinity of the fluororesin in the fluororesin film is set to 70% or more, the ablation process can be efficiently performed.

Further, since the fluororesin substrate of the present invention is excellent in low dielectric properties and mechanical properties and has a high-density wiring pitch, it is miniaturized and highly functionalized, and the electrical signal response is improved. A high-speed low-dielectric circuit board can be provided.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09D 127/12 PFJ 179/08 PLZ H05K 1/02 Z // H01L 23/14 (72) Inventor Shoji Morita Osaka 1-2 1-2 Shimohozumi, Ibaraki City, Ibaraki Prefecture Nitto Denko Corporation (72) Inventor Atsushi Hino 1-2 1-2 Shimohozumi Shimohozumi, Ibaraki City, Osaka Prefecture

Claims (11)

[Claims] 1. A fluororesin composition for ablation processing, which comprises a resin having an absorption wavelength in the ultraviolet region and a fluororesin. 2. The fluororesin composition for ablation processing according to claim 1, wherein the resin having an absorption wavelength in the ultraviolet region is contained in an amount of 1 to 125 parts by weight with respect to 100 parts by weight of the fluororesin. 3. The fluororesin composition for ablation processing according to claim 1, which comprises a fluororesin dispersion and a resin solution or dispersion having an absorption wavelength in the ultraviolet region. 4. The fluororesin composition for ablation processing according to claim 1, comprising a fluororesin powder and a resin powder having an absorption wavelength in the ultraviolet range. 5. The fluororesin composition for ablation processing according to claim 1, wherein the film-shaped fluororesin contains a resin having an absorption wavelength in the ultraviolet region. 6. The fluororesin composition for ablation processing according to claim 1, wherein the resin having an absorption wavelength in the ultraviolet region is a polyimide resin. 7. A step of forming a fluororesin-containing film with the fluororesin composition according to claim 1, a step of irradiating the fluororesin-containing film with an ultraviolet laser, and the ultraviolet laser if necessary. And a step of curing the fluororesin-containing film irradiated with. 8. The fluororesin-containing film is formed by coating the support with the fluororesin composition according to claim 3 and then volatilizing a solvent or a dispersion medium.
A method for producing the processed fluororesin substrate described. 9. The method for producing a fluororesin substrate according to claim 7, wherein the fluororesin-containing film is formed by heating and pressing the fluororesin composition according to claim 4. 10. The method for producing a fluororesin substrate according to claim 7, wherein the fluororesin-containing film is formed from the fluororesin composition according to claim 5. 11. The crystallinity of the fluororesin in the fluororesin-containing film is 70% or more as measured by the wide-angle X-ray diffraction method, according to any one of claims 7 to 10. Manufacturing method of fluororesin substrate.