JP2002374055A - Method of forming metal circuit pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of forming a metal circuit pattern, in which the adhesion strength of a polyimide substrate to a metal circuit part is high and in which the line-to-line insulation resistance of the metal circuit part is high. SOLUTION: The method of forming the metal circuit pattern comprises a substrate-metal layer formation process, where a polyimide resin precursor layer 2 containing a palladium compound is formed on the polyimide substrate 1, the precursor layer 2 is irradiated with ultraviolet rays 7 via a photomask 3 in a state where a hydrogen donator 4 exists only in a metal-circuit forming part, a plating-substrate nucleus is formed in the metal-circuit formation part and an electroless plating treatment is executed and a metal-circuit formation process where a plating treatment is executed to form the metal circuit part 9 on a substrate metal layer 8, an imidization process is executed to change the precursor layer 2 into a polyimide resin layer by a heating operation and a removal treatment is executed to remove the precursor layer 2 or the polyimide resin layer in a nonmetal-circuit forming part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a metal circuit pattern on a polyimide substrate used for a flexible printed circuit board, a CSP (Chip Scale Package), a board for a hard disk drive, a built-up multilayer board, and the like. .

[0002]

2. Description of the Related Art In general, when a metal circuit pattern such as copper wiring is formed on a polyimide base material, a photoresist is applied to a copper-clad polyimide base material in which a copper foil is stuck to a polyimide film base material using an adhesive. A method of etching a copper foil after exposure and development is used.

However, in this method, since the thickness of the copper foil is relatively large, it takes a long time to perform etching. Particularly, in the case of forming fine wiring, the leading end of the wiring is shaved and disconnection easily occurs. However, there is a problem that it is difficult to form a reliable fine wiring.

In order to solve the above-mentioned problems in the etching method, a method of forming a metal wiring circuit by an additive method on a thin-film copper-clad polyimide base material obtained by a sputtering method with a thin copper foil is also proposed. It has been devised.

Further, a method of forming a metal circuit pattern disclosed in Japanese Patent Application No. 2001-86876 and a method disclosed in Japanese Patent Application No. 2001-8687, in which the catalytic activity of a metal complex is deactivated by irradiating ultraviolet rays.
No. 7 metal circuit pattern forming method and the like have been proposed.

In a metal circuit pattern forming method disclosed in Japanese Patent Application No. 2001-86877, a polyimide resin precursor solution containing a palladium compound is applied on a polyimide substrate and dried to form a polyimide resin precursor layer, and a hydrogen donor is formed. The metal circuit forming portion is opened in the presence of, and the non-metal circuit forming portion is irradiated with ultraviolet light through a photomask having a light-shielded pattern to form a plating base nucleus (hereinafter, an ultraviolet irradiation step for forming a base nucleus). Next, the photomask and the hydrogen donor are removed, and the entire surface of the polyimide resin precursor layer is irradiated with ultraviolet rays in the air (hereinafter, referred to as an ultraviolet irradiation step 1 for utilizing the plating catalyst power). Thereby, the palladium ions in the palladium compound of the non-metallic circuit forming portion are converted to palladium oxide having no catalytic ability for electroless plating. Thereafter, a base metal layer forming step of forming a base metal layer by electroless plating, a plating process of forming a metal circuit portion on the base metal layer, and heating and imidizing the polyimide resin precursor layer to obtain a polyimide resin A metal circuit forming step including an imidization process for forming a layer and a removal process for removing the polyimide resin precursor layer or the polyimide resin layer in the non-metal circuit formation portion.

Further, a metal circuit pattern forming method disclosed in Japanese Patent Application No. 2001-86876 discloses a method of applying a polyimide resin precursor solution containing a palladium compound onto a polyimide substrate.
It is dried to form a polyimide resin precursor layer, and is irradiated with ultraviolet light in air through a photomask having a pattern in which a metal circuit forming portion is shielded from light and a non-metal circuit forming portion is opened (hereinafter referred to as a plating catalyst. The ultraviolet irradiation step 2), the palladium ions in the palladium compound in the non-metallic circuit forming part are converted into palladium oxides having no catalytic ability for electroless plating, and then the photomask is removed and the hydrogen donor is present. Under the polyimide resin precursor layer, the entire surface of the polyimide resin precursor layer is irradiated with ultraviolet rays (hereinafter referred to as an ultraviolet irradiation step 2 for forming an underlayer nucleus), and a plating underlayer nucleus is formed in a metal circuit forming portion. A base metal layer forming step of forming a plating base metal layer on a formation part, a plating process of forming a metal circuit part on the plating base metal layer, the polyimide resin A metal circuit forming step comprising an imidization treatment in which the precursor layer is heated and imidized into a polyimide resin layer, and a removal treatment for removing the polyimide resin precursor layer or the polyimide resin layer in the non-metal circuit formation portion. Is a method of forming a metal circuit pattern.

[0008]

SUMMARY OF THE INVENTION However, Japanese Patent Application No.
No. 001-86877 discloses a method for forming a metal circuit pattern.
First, in the presence of a hydrogen donor, an ultraviolet irradiation step 1 for forming a base nucleus is performed on a metal circuit forming portion of a photomask opening.
After that, the photomask and the hydrogen donor are removed, and the entire surface of the polyimide resin precursor layer is subjected to an ultraviolet irradiation step 1 in which air is applied to the entire surface of the polyimide resin precursor layer. The palladium nucleus serving as a plating base nucleus formed in the ultraviolet irradiation step 1 of the above is subjected to ultraviolet irradiation in air in the second ultraviolet irradiation step 1 utilizing the disabling of the plating catalyst, and the plating base of the metal circuit forming portion is exposed. In some cases, a palladium nucleus serving as a nucleus is partially oxidized to form palladium oxide, and there has been a problem that a boundary between a metal circuit portion and a non-metal circuit portion cannot be formed sharply.

In the metal circuit pattern forming method disclosed in Japanese Patent Application No. 2001-86876, first, in the ultraviolet irradiation step 2 in which the non-metal circuit forming portion is utilized by losing plating catalytic ability.
When the ultraviolet irradiation is not sufficient, the portion of the non-metallic circuit forming portion which has been subjected to the plating catalyst inactivation treatment in the next step, the ultraviolet irradiation step 2 for forming a base nucleus in the presence of a hydrogen donor, is a hydrogen donor. In some cases, the catalytic activity may be restored again by the photoreduction effect of ultraviolet irradiation in the presence, and as a result, a plating reaction also occurs in the non-metal circuit forming part, and the boundary between the metal circuit part and the non-metal circuit part is sharply formed. There was a problem that it was not possible.

The present invention relates to the above-mentioned Japanese Patent Application No. 2001-8687.
No. 7 or Japanese Patent Application No. 2001-86876 solves the problem of thinning and disconnection of a metal wiring portion which is observed in the formation of a metal wiring circuit by a conventional etching method. An object of the present invention is to provide a method for forming a metal circuit pattern having a higher adhesion between metal and polyimide.

In addition, since the present invention forms a circuit pattern by irradiating ultraviolet rays once and performing general electroless plating or electrolytic plating, it is excellent in both workability and economy.

[0012]

In order to achieve the above object, in the present invention, a polyimide resin precursor solution containing a palladium compound is applied on a polyimide substrate.
Dry to form a polyimide resin precursor layer, open the non-metal circuit formation portion, and form the metal circuit through an ultraviolet transmission type photomask where the metal circuit formation portion and the non-metal circuit formation portion are simultaneously exposed. After irradiating ultraviolet rays in a state where a hydrogen donor is present in a part and a hydrogen donor is not present in a non-metal circuit forming part, a plating base nucleus is formed in a metal circuit forming part and a photomask is removed, and then electroless. A base metal layer forming step of forming a base metal layer by plating;
Plating treatment for forming a metal circuit portion on the plating base metal layer, imidization treatment for heating and imidizing the polyimide resin precursor layer into a polyimide resin layer, polyimide resin precursor layer or polyimide resin for a non-metal circuit formation portion A metal circuit forming step including a removing process for removing the layer.

Therefore, a part of the plating base metal layer is embedded in the polyimide resin layer of the same quality as the polyimide base material in an anchor shape, and the metal circuit and the polyimide base material are formed by the anchor effect of the plating base metal layer. Since the adhesion strength of the metal circuit portion is increased and the boundary between the metal circuit portion and the non-metal circuit portion is clearly formed, a very fine metal circuit can be formed.

The polyimide resin precursor solution is prepared by dispersing a palladium compound in a polyimide resin precursor varnish comprising at least one of polyamic acid and a derivative of polyamic acid, and forming a complex between the palladium compound and the polyimide resin precursor. The solution forming is used.

As the palladium compound, a palladium acetylacetone complex is often used, and as the hydrogen donor, water, alcohol or an aqueous alcohol solution is used. In addition, the polyimide resin precursor layer and the polyimide resin layer containing the complex existing in portions other than the metal circuit portion are removed with an aqueous solution of an alkali metal hydroxide and an amine compound or an aqueous solution of an alkali metal permanganate. Thereby, a metal circuit pattern having excellent insulation resistance between lines can be formed.

[0016]

FIG. 1 shows an embodiment of a metal circuit pattern forming method according to the present invention.

A polyimide resin precursor solution containing a palladium compound is applied and dried on a polyimide substrate 1 to form a polyimide resin precursor layer 2, a non-metal circuit forming section 5 is opened, and a metal circuit forming section is formed. A hydrogen donor 6 is present in the metal circuit forming section 4 and hydrogen is supplied to the non-metal circuit forming section 5 via the ultraviolet-transmitting photomask 3 in which the non-metal circuit forming section 4 and the non-metal circuit forming section 5 are simultaneously exposed. Irradiation of ultraviolet rays 7 in the absence of the body 6 converts the palladium ions in the palladium compound of the non-metallic circuit forming part 5 into palladium oxide having no catalytic ability for electroless plating, After forming a plating base nucleus by reducing to palladium metal (FIG. 1 (a)), the photomask is removed (FIG. 1 (b)), and the plating base is formed by electroless plating. Forming the genus layer 8 (FIG. 1 (c)).

Next, a metal circuit portion 9 having a predetermined film thickness is formed on the plating base metal layer 8 by electrolytic plating.
(D)) The polyimide resin precursor layer 2 of the non-metallic circuit forming portion 5 is removed (FIG. 1 (e)), and the polyimide resin precursor layer 2 is heated at 400 ° C. in a vacuum or a nitrogen atmosphere. (FIG. 1 (f)) to form a metal circuit pattern.

If the removal of the polyimide resin precursor layer 2 of the non-metallic circuit formation portion 5 is performed before the formation of the metal circuit portion 9 by plating, the removal of the polyimide resin precursor layer 2 by the plating base metal Since the layer 8 may peel off,
The removal of the polyimide resin precursor layer 2 in the non-metallic circuit forming portion 5 is preferably performed after the plating process.

The polyimide substrate used in the present invention includes a non-thermoplastic polyimide resin and a thermoplastic polyimide resin. For example, pyromellitic anhydride (PMDA)
Polyimide comprising oxydianiline (ODA), polyimide comprising biphenyltetracarboxylic anhydride (BTDA) and p-phenylenediamine (PDA) and copolymers of these monomers, aromatic tetracarboxylic anhydride and Solvent-soluble heat, such as a thermoplastic polyimide comprising an aromatic diamine having a bending group such as -O-, -CO-, -Si-, and a copolymer with an alicyclic carboxylic anhydride. Examples thereof include plastic polyimides, and these polyimide substrates are mainly used as film substrates in the field of electronic component materials.

As the polyimide resin precursor solution, a polyamic acid varnish obtained from the same monomer component as the polyimide, or a polyamic acid varnish containing a photosensitive group in a molecule, or a solvent-soluble polyimide varnish may be used. It is important that the varnish has a structure in which the palladium compound is dispersed and a part thereof is exposed on the surface. As the varnish, for example, Toray Industries, Inc.
And "Photo Nice" varnish, "U-varnish" of Ube Industries, Ltd., and the like, and a mixture of a polyimide resin precursor varnish and a solvent-soluble polyimide varnish can also be used. Nippon Steel Chemical's thermoplastic polyimide varnish "SPI-2" is a solvent-soluble polyimide varnish.
00N ". When a solvent-soluble polyimide varnish is used, it is preferable to use it by mixing it with a polyimide resin precursor varnish.

The palladium compound includes an organic carbonyl complex of palladium. Examples of the organic carbonyl compound constituting the complex include β-diketones such as acetylacetone complex and dibenzoylmethane complex, and β-ketocarboxylic acid esters such as ethyl acetoacetate. , EDTA complex,
Oxalic acid complexes and the like. In particular, an acetylacetone complex is preferable in terms of easy availability, solubility in an organic solvent, thermal stability, and the like.

The organic carbonyl complex may be a solvent for a polyimide resin precursor such as n-methyl-2-pyrrolidinone (hereinafter abbreviated as NMP) or NN'-dimethylacetamide (DMM).
Ac), mixed and dissolved in a polyimide resin precursor varnish, and applied as a thin film layer on a polyimide substrate using, for example, a spin coater or a bar coater, or further by screen printing, etc. Is dried at a temperature equal to or lower than the thermal decomposition temperature, usually 150 ° C. or lower. The thickness of the polyimide resin precursor layer after drying is usually 0.1.
The complex concentration in the polyimide resin precursor layer is about 0.1 to 10% by weight. The screen printing method is preferable for forming wirings and connection bumps directly on a polyimide substrate without going through a process such as photolithography.

The ultraviolet rays used in the present invention include a wavelength of 4 emitted from an ultraviolet lamp or an ultraviolet laser generator.
Light of 50 nm or less (energy of 2.75 ev or more) is effective, and ultraviolet light of 370 nm or less is particularly effective, and ultraviolet light of 254 nm or less is particularly effective. A commercially available low-pressure mercury lamp can be used as the ultraviolet lamp, but a laser generator or the like may also be used.

The amount of UV irradiation is 500 to 150 when measured with an UV illuminometer UV-02 manufactured by Oak Manufacturing Co., Ltd.
Energy of about 00 mJ / cm <2> is required, and particularly preferably about 1500 to 9000 mJ / cm <2>.
If the amount of ultraviolet irradiation is less than 500 mJ / cm 2, palladium ions of the palladium compound may not be completely reduced to palladium metal, and if it exceeds 15000 mJ / cm 2, the polyimide resin precursor layer may be damaged. When the ultraviolet irradiation amount is 1500 to 9000 mJ / cm 2, palladium ions are stably reduced to palladium metal.

The irradiation time required to obtain the above-mentioned irradiation amount of ultraviolet rays varies depending on the irradiation intensity of ultraviolet rays, but the irradiation time of a normal ultraviolet lamp is about 1 minute to 20 minutes. Means that the irradiation time is within 60 seconds.

Examples of the hydrogen donor include water, alcohol, and an aqueous alcohol solution. In particular, an aqueous alcohol solution that has little ultraviolet absorption in the above-mentioned ultraviolet wavelength region and has an appropriate wettability with the surface of the polyimide resin precursor layer. Is preferably used. Note that the reaction of reducing metal ions to metal is inhibited by the presence of oxygen. Therefore, it is preferable to block oxygen (air) during irradiation.

It is possible to add a sensitizer in order to promote the photoreaction between the palladium compound and the ultraviolet ray, as long as there is no particular adverse effect on the adhesion between the metal and the polyimide.

The electroless plating bath for forming the base metal layer is not particularly limited, but is generally neutral to weak in view of the barrier properties against metal ions and the chemical resistance (alkali resistance) of the polyimide resin precursor. An acidic hypophosphite or dimethylaminoborane nickel plating bath is preferably used. As the electrolytic plating bath, a normal electrolytic copper plating or electrolytic nickel plating bath or the like can be used.

As a chemical solution for removing the polyimide resin precursor layer or the polyimide resin layer, a polyimide etching solution comprising an alkali metal hydroxide and an amine compound or an aqueous solution of an alkali metal permanganate can be used.

When an aqueous alkaline etching solution is used, a chemical solution having a low water content is preferable in order to reduce the damage to the remaining polyimide resin precursor layer. For example, the alkali metal hydroxide and the amine compound each contain at least 25%, especially It is preferable to perform the etching in a state where 30% or more of each is included. For example, an etchant "TPE3000" manufactured by Toray Engineering Co., Ltd. containing 25% or more of an alkali metal hydroxide and an amine compound can be used.

When an aqueous solution of an alkali metal permanganate is used, an aqueous solution having a concentration of about 0.05 to 0.2 mol and a weakly alkaline aqueous solution having a pH of 8 to 12 can be used.
Excess permanganate adhering to the polyimide substrate or the like is washed with water and then reduced and removed with hydroxylammonium hydrochloride.

The conditions for removing the polyimide resin precursor layer depend on the film thickness and the dimensions of the portion to be removed. However, when the above-mentioned solvent is used, the polyimide resin precursor layer is removed at 60 to 80 ° C. for about 1 to 6 minutes. Can be completely removed.

In the imidization treatment, the polyimide resin precursor layer is imidized by heating to around 400 ° C. to form a polyimide resin layer. Note that the heating is preferably performed in an atmosphere containing no oxygen, such as a vacuum or a nitrogen atmosphere.

An example based on the above embodiment is as follows.

Example 1 A solution prepared by dissolving a palladium acetylacetone complex (hereinafter abbreviated as a palladium complex) in n-methyl-2-pyrrolidinone (hereinafter abbreviated as NMP) was prepared by using a polyimide precursor varnish “Trenees” manufactured by Toray Industries, Inc. "#
3,000 and adjusted so that the content of the palladium complex per varnish solution is 1 wt / vol%. The solution contains about 5% by weight of a palladium complex per polyimide resin precursor.

Next, a 10 × 10 cm (thickness: 5 × 10 cm) sample of a polyimide substrate “UPILEX-S” manufactured by Ube Industries, Ltd.
0 μm) was roughened with a 1% aqueous NaOH solution and a 1% aqueous HCl solution, washed with pure water and dried, and then coated with the above-mentioned “pure complex” varnish containing a palladium complex with a bar coater. After drying at ℃, the thickness of the coating film was about 5 μm. The XPS analysis result of the surface of the polyimide resin precursor thin film is as shown by a dotted line in FIG. 2, and the presence of palladium ions is recognized on the surface.

Next, the surface of the polyimide substrate is wetted with water, and is sandwiched between quartz plate masks in which the non-metallic circuit forming portions are opened. A film is formed, and the water film of the non-metallic circuit forming portion is formed on the surface of the non-metallic circuit forming portion by removing the water film from the mask opening, for example, by blowing clean compressed air into the mask opening. And contacted. Thereafter, ultraviolet rays from a low-pressure mercury lamp were irradiated for 3 minutes. The irradiation amount of the ultraviolet ray was measured by an illuminometer UV-02 manufactured by Oak Manufacturing Co., Ltd., and the result was 4500 mJ.
/ Cm2. The XPS analysis result of the surface of the circuit portion of the polyimide base material is as shown by a solid line in FIG. 2, and it can be seen that palladium ions in the palladium metal complex are reduced to palladium metal. The XPS analysis result of the surface of the non-metallic circuit portion of the polyimide base material is observed as a spectrum of a palladium oxide in FIG.

Further, an electroless nickel bath "Emprate Ni-426" using sodium hypophosphite manufactured by Meltec Co., Ltd. heated to 65.degree.
(PH = 6-7) for 3 minutes, plating with a uniform metallic luster proceeds only in the metal circuit forming portion, and there is no plating reaction in the non-metal circuit forming portion, as shown in FIG. A desired circuit pattern having a sharp boundary between the circuit portion and the non-circuit portion was formed. As a result of measuring the Auger spectrum in the depth direction from the nickel-plated portion on the surface of the polyimide base material to the polyimide resin precursor thin film therebelow, as shown in FIG. 4, nickel was transferred from the plated portion to the polyimide resin precursor thin-film portion. It was detected to the deep part, and it was confirmed that nickel metal was present in the polymer layer.

Thereafter, the polyimide substrate was subjected to electrolytic copper plating at a current density of 3.3 A / dm 2 in an electrolytic copper plating bath to form a metal circuit pattern having a thickness of 5 μm.

After the polyimide substrate was dried at 150 ° C. in a nitrogen atmosphere, it was further heated to 400 ° C. and kept at 400 ° C. for 15 minutes to imidize the polyimide resin precursor. And cooled to room temperature to obtain an all-polyimide substrate having a metal circuit pattern.

Next, the polyimide substrate was coated with a polyimide etching solution “TPE” manufactured by Toray Engineering Co., Ltd.
Etching was performed at -3000 "for 2 minutes at 80 ° C. to remove the polyimide resin precursor thin film in the non-metallic circuit forming portion 5 to obtain a film having a metal circuit pattern of L / S = 100/100 (μm). The insulation resistance between wires of the film was 1.0 × 10 1 as a result of measurement according to JISC-5016.
The insulation resistance value was higher by 2Ω · cm.

The metal circuit pattern was excellent in adhesion to the polyimide substrate, and the metal circuit was not peeled off in the peeling test of the obtained film with the cellophane tape.

(Example 2) In Example 1, in order to remove the palladium-containing thin film layer on the film surface other than the metal circuit portion (space portion, etc.), instead of the polyimide etching solution "TPE-3000", 0 A metal wiring pattern was prepared by performing exactly the same operation except that the treatment was performed at 70 ° C. for 5 minutes using an aqueous solution of 0.1 mol of potassium permanganate. The line insulation resistance of the obtained metal wiring circuit is 1.1
X10 12 Ω · cm, the metal circuit pattern has excellent adhesion to the polyimide substrate, and the metal circuit is not peeled off in the peeling test of the obtained film metal circuit and the polyimide substrate with cellophane tape. Was.

(Comparative Example 1)
When a metal circuit pattern was formed by electroless plating using a method described in Japanese Patent Application Laid-Open No. 1-868877, a plating reaction also occurred in a non-metal circuit forming portion as shown in FIG. The boundary of the metal circuit forming portion blurred, and a sharp boundary could not be formed.

[0046]

According to the metal circuit pattern forming method of the present invention, a polyimide resin precursor solution containing a palladium compound is applied on a polyimide substrate and dried to form a polyimide resin precursor layer. In the presence of a hydrogen donor in the metal circuit forming part, through an ultraviolet transmission type photomask that is formed, the non-metal circuit forming part is opened, and the metal circuit forming part and the non-metal circuit forming part are simultaneously exposed. By irradiating ultraviolet rays in a state where no hydrogen donor is present in the non-metal circuit forming part, a plating base nucleus is formed in the metal circuit forming part, and at the same time, the surface of the non-metal circuit forming part is inactive. Therefore, after removing the photomask, the plating base metal layer can be formed only in the metal circuit forming portion by electroless plating. after that,
Plating treatment for forming a metal circuit portion on the plating base metal layer, imidization treatment for heating and imidizing the polyimide resin precursor layer into a polyimide resin layer, polyimide resin precursor layer or polyimide resin for a non-metal circuit formation portion Since it has a metal circuit formation process consisting of a removal process to remove the layer, the adhesion strength between the metal circuit and the resin can be achieved by a single irradiation of ultraviolet light at room temperature and normal pressure without performing a sputtering process in a high vacuum. It is possible to easily and reliably form a metal circuit pattern having a very high level of fineness and excellent fine line insulation.

As described in claim 2, when a thin film formed from a polyimide resin precursor varnish that is a derivative of at least one of polyamic acid and riamic acid is used as the polyimide resin precursor thin film, palladium is used as the thin film. Since the organic complex is uniformly distributed and the palladium complex is distributed on the surface as a component of the polymer molecules on the surface of the thin film, metal palladium is generated in the surface and in the thin film near the surface by ultraviolet irradiation, and electroless plating is performed. When,
For example, in the case of Ni electroless plating, Ni enters the thin film from the surface of the thin film, and Ni as a base metal is wrapped in polyimide resin of the same quality as the base material by imidization of the thin film in a later step. Since it is present in a state where the base metal portion has a sufficient anchor effect, it is possible to form a base metal portion having high adhesion to a polyimide base material.

As described in claim 3, a palladium acetylacetone complex is used as the palladium organic complex,
By using water, alcohol or an aqueous alcohol solution as a hydrogen donor, and irradiating ultraviolet light having a wavelength of 450 nm or less, it is possible to efficiently and stably reduce palladium ions of a palladium complex to palladium metal by ultraviolet irradiation. .

According to a fourth aspect of the present invention, an aqueous solution of an alkali metal hydroxide and an amine compound is used to remove the polyimide resin precursor thin film, or an aqueous solution of an alkali metal permanganate is used to remove the non-metallic metal. The polyimide precursor thin film in the circuit section can be selectively and easily removed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a method of forming a metal circuit pattern according to one embodiment of the present invention, wherein (a) is a polyimide substrate 1
A polyimide resin precursor solution containing a palladium compound is applied thereon and dried to form a polyimide resin precursor layer 2, a non-metal circuit forming section 5 is opened, and a metal circuit forming section 4 and a non-metal circuit forming section are formed. A metal circuit forming portion 4 is formed through an ultraviolet-transmitting photomask 3 which is simultaneously exposed.
Is irradiated with ultraviolet rays 7 in a state where the hydrogen donor 6 is present and the hydrogen donor 6 is not present in the non-metallic circuit forming portion 5, and the palladium ions in the palladium compound in the non-metallic circuit forming portion 5 are subjected to electroless plating. On the other hand, a cross-sectional view showing a state where a plating base nucleus is formed by converting palladium ions of the metal circuit forming part 4 into palladium metal having no catalytic ability and reducing palladium ions of the metal circuit forming part 4 to palladium metal, FIG. FIG. 3C is a cross-sectional view showing a state in which a base metal part is formed by electroless plating. FIG. 4D is a cross-sectional view showing a state in which a metal circuit part having a predetermined film thickness is formed on the base metal part by electroplating. FIG. 9E is a cross-sectional view showing a state where the polyimide resin precursor thin film in the non-metal circuit forming portion is removed.
(F) is a sectional view showing a state in which the polyimide substrate is heated to imidize the polyimide resin precursor thin film.

FIG. 2 shows XP showing changes in binding energy of palladium in a palladium complex-containing resin thin film layer before and after irradiation with ultraviolet light.
It is a figure showing an S analysis result.

FIG. 3 is a view showing an XPS analysis result showing a change in binding energy of a palladium complex-containing resin thin film layer after ultraviolet irradiation.

FIG. 4 is an Auger analysis chart of a nickel plated portion and a polyimide resin precursor thin film after electroless nickel plating.

FIG. 5 is a top view of a plating-underlying metal circuit pattern formed by an electroless plating process formed by the metal circuit pattern forming method of the present invention.

FIG. 6 is a top view of a metal circuit pattern under plating by electroless plating formed by a conventional metal circuit pattern forming method.

[Description of Signs] 1 polyimide substrate 2 polyimide resin precursor layer 3 photomask 6 hydrogen donor 7 ultraviolet ray

Continuing on the front page (72) Inventor Ito ▲ Mineral Tsukasa 1-1-45 Oe, Otsu City, Shiga Prefecture Toray Engineering Co., Ltd. ) Inventor Atsushi Suzuki 1-103-54 Yoshinodai, Kawagoe-shi, Saitama F-term in Ray-Tech Co., Ltd. CA15 CA18 CA53 CA62 5E343 AA02 AA12 AA18 AA33 BB24 BB71 CC62 CC73 DD33 DD43 ER01 ER05 ER11 ER57 GG01 GG08

Claims (4)

[Claims] 1. A polyimide resin precursor solution containing a palladium compound is applied and dried on a polyimide substrate to form a polyimide resin precursor layer, a non-metal circuit forming portion is opened, and a metal circuit forming portion and Irradiation of ultraviolet rays through a UV-transmitting photomask that simultaneously exposes the non-metallic circuit formation part in a state where the hydrogen donor is present in the metal circuit formation part and the hydrogen donor is not present in the non-metallic circuit formation part Forming a plating base nucleus in the metal circuit forming portion, removing the photomask, and then forming a plating base metal layer by electroless plating, and forming a metal circuit portion on the plating base metal layer. A plating process to form a polyimide resin precursor layer by heating and imidizing the polyimide resin precursor layer into a polyimide resin layer, a polyimide resin precursor layer in a non-metal circuit forming portion or A metal circuit forming step comprising a removing process for removing the polyimide resin layer. 2. A polyimide resin precursor solution, in which a palladium compound is dispersed in a polyimide resin precursor varnish comprising at least one of a polyamic acid and a polyamic acid derivative, and the palladium compound and the polyimide resin precursor are mixed with each other. The method for forming a metal circuit pattern according to claim 1, wherein a complex is formed. 3. The method for forming a metal circuit pattern according to claim 1, wherein a palladium acetylacetone complex is used as the palladium compound, and water, alcohol or an aqueous alcohol solution is used as the hydrogen donor. 4. An aqueous solution of an alkali metal hydroxide and an amine compound or an aqueous solution of an alkali metal permanganate is used for removing the polyimide resin precursor layer and the polyimide resin layer. Item 3. The method for forming a metal circuit pattern according to Item 1.