JPS63126297A - Multilayer printed interconnection board and manufacture of the same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a multilayer printed wiring board and a method for manufacturing the same. The present invention relates to a multilayer printed wiring board in which insulating layers made of resin are alternately laminated, and a method for manufacturing the same.

(Prior Art) In recent years, with the progress of electronic technology, efforts have been made to increase the density and speed of arithmetic operations for electronic devices such as large-sized computers. As a result, even in printed wiring boards, a multilayer printed wiring board formed of wiring circuits or multilayers is used, with the aim of increasing density.

Conventionally, multilayer printed wiring boards have been produced by, for example, laminating and pressing a plurality of circuit boards on which inner layer circuits are formed using prepreg as an insulating layer, and then connecting each inner layer circuit with through holes to provide continuity. It was used.

However, in the multilayer printed wiring board as described above, through holes are formed in a plurality of inner layer circuits to connect the inner layer circuits.
Since it is electrically conductive, it is difficult to form a complicated wiring circuit to achieve higher density or higher speed.

A multilayer pudding that can overcome these difficulties
-Recently, as wiring boards, the development of multilayer printed wiring boards in which conductive circuits and organic insulating films are alternately built up has been actively progressed. Although this multilayer printed wiring board is suitable for ultra-high density and high speed, it is difficult to reliably form an electroless plating film on the organic insulating film 1-. The conductor circuit is
PVD method such as steam vaporization or sputter link or the above PV
The conductor circuit formation method using the PVD method, which is formed by a combination of the D method and electroless plating, has the disadvantage of poor productivity and high cost.

(Problem to be solved) As mentioned above,
Conventionally, a multilayer printed wiring board having a multilayer structure in which a conductor circuit made of an electroless plated film and an organic insulating film are built up in a mating manner has not been known.

Honffi I! I+ is the conventional multilayer pudding 1~
Our goal is to eliminate the drawbacks of wiring boards and easily and inexpensively provide multilayer printed wiring boards in which conductive circuits made of electroless plated films and organic insulating films are alternately pill-shielded. It is something.

(Means for Solving the Problems) As a result of various studies aimed at solving the above-mentioned problems, the present inventors found that a conductor circuit made of an electroless plating film and a resin layer with excellent heat resistance are alternately formed. A mixture of a laminated multilayer printed wiring board and an uncured photosensitive resin liquid that is hardly soluble in a specific chemical liquid due to its properties after curing, in which particulate matter soluble in the chemical liquid is dispersed. Applying the liquid to the conductor layer (coating 711 on the board to form a photosensitive resin layer,
After exposing a predetermined location on the surface of the photosensitive resin layer, a step of developing and etching is performed, using the specific chemical solution to dissolve and remove the particulate matter present on the surface portion of the resin layer, and remove the resin. The present invention was completed by discovering that the above-mentioned problems can be solved by a method for manufacturing a multilayer printed wiring board, which comprises at least the steps of roughening the surface of the layer and forming a conductor layer by electroless plating. This is what I did.

The present invention will be explained in detail below.

The multilayer printed wiring board of the present invention is a multilayer printed wiring board in which conductor circuits made of electroless plated films and insulating layers made of resin with excellent heat resistance are alternately laminated.

The reason why it is necessary to use the conductor circuit of the multilayer printed wiring board or the electroless plated film is that it is easy to use in production and is suitable for high-density wiring.

In addition, the reason why the insulating layer needs to be made of resin with excellent heat resistance is that the insulating layer formed of resin has a low dielectric constant and can be made thicker, which makes it possible to increase speed. This is because it is suitable.

It is extremely important that the insulating layer of the present invention has excellent adhesion to electroless plating. and the interface with the electroless plating film has a recess formed as a result of the soluble particulate matter being dissolved by a specific chemical solution, and an electroless plating anchor is formed in the recess. It is necessary to become

Hereinafter, the method for manufacturing a multilayer printed wiring board of the present invention will also be described in detail.

According to the present invention, a conductive layer is formed by dispersing a mixed liquid in which particulate matter soluble in the chemical liquid is dispersed in an uncured photosensitive resin liquid that is poorly soluble in a specific chemical liquid due to its properties after curing. It is necessary to form a photosensitive resin layer by coating the photosensitive resin layer on a substrate having a photosensitive resin. The reason for forming such a photosensitive resin layer is that the photosensitive resin layer forms an insulating layer in which particulate matter soluble in a specific chemical solution is dispersed, and is photosensitive. Since the resin is a matrix, it is possible to easily form via holes, etc., which are essential for multilayering, by exposing a predetermined area to light, developing, and etching. Since resins have different solubility in specific chemical solutions, by treating the photosensitive resin layer after curing with a specific chemical solution, particulate matter present on the surface of the resin layer can be dissolved and removed. This is because the surface of the resin layer can be roughened. As a result, an insulating layer with excellent adhesion to the electroless plating film can be formed.

The particulate matter soluble in the specific chemical solution is preferably at least one of heat-resistant resin fine powder or inorganic fine particles which have been cured in advance.

The reason why it is preferable to use heat-resistant resin fine powder that has been pre-cured as the particulate material is as follows. This is because when added to a liquid dissolved using a solvent, it dissolves in the resin liquid, so there is no difference in solubility for specific chemical solutions, and it is no longer possible to roughen the surface of the resin layer. . On the other hand, if the heat-resistant resin fine powder is cured in advance, it becomes poorly soluble in the photosensitive resin or the solvent that dissolves this resin, so the heat-resistant resin fine powder is uniformly dispersed in the photosensitive resin. This is because a photosensitive resin layer in a dispersed state can be formed.

The material of the heat-resistant resin fine powder has excellent heat resistance and electrical insulation properties, is stable against ordinary chemicals, and is resistant to photosensitive resin liquid or solvents that dissolve this resin by being hardened in advance. Resins that are soluble and can be dissolved by specific chemicals such as chromic acid may be used, especially epoxy resins, polyester resins, and bismaleimide-triazine resins. It is preferable to use at least one selected from the following, and among them, epoxy resin is the most preferable because it has excellent characteristics. As the method of curing, a method of curing by heating or a method of curing by adding a catalyst can be used, and in particular, a method of curing by heating is the most practical. Note that specific chemical solutions for dissolving and removing the heat-resistant resin fine powder include oxidizing agents such as chromic acid, chromates, permanganates, and ozone, and a mixed aqueous solution of chromic acid and sulfuric acid is particularly advantageous. You can use it.

The reason why it is preferable to use inorganic fine particles as the particulate material is because =a? j Fine particles are generally soluble in a strong acid solution such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, or a mixture thereof, or a strong alkaline solution such as sodium hydroxide, and the above-mentioned strong acid solution or strong alkaline solution is used between the photosensitive resin and the photosensitive resin. This is because there is a difference in solubility between the two. The inorganic fine particles are soluble in a strong acid solution such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, or a mixture thereof, or a strong alkaline solution such as sodium hydroxide, and have heat resistance, electrical insulation properties, and the above-mentioned strong acid. It is preferable to use materials that have stability against chemicals other than strong alkalis, such as silica, titanium oxide, zirconia, zinc oxide, glass, etc. In particular, for example, crystalline silica, Inorganic fine particles mainly containing SiO2, such as fused silica, mullite, sillimanite, and silica-based glass, are advantageous because they can be easily dissolved in an aqueous hydrofluoric acid solution and have excellent properties.

As for the particle size of the particulate matter, it is preferable that the average particle size is 0 gm or less, and particularly preferably 5 uLm or less. The reason for this is that if the average particle size is larger than 1 gm, the density of the anchor formed by dissolving and removing it will be low and likely to be non-uniform, resulting in a decrease in adhesion strength and reliability, and furthermore, insulating This is because the unevenness of the surface of the layer becomes severe, making it particularly undesirable for fine patterns of conductor circuits, and for mounting parts and the like. The heat-resistant resin fine powder that determines the particle size is, for example, heat-cured heat-resistant resin and then finely pulverized using a shet mill or freeze-pulverizer, or spray-dried heat-resistant resin solution after curing treatment. It can be obtained by various means such as directly turning it into a fine powder.

The photosensitive resin in which the particulate material used in the present invention is dispersed has excellent heat resistance, electrical insulation, chemical stability, and adhesive properties, and has properties after curing that make it poorly soluble in certain chemicals. If you have a photosensitive resin, you can use it.
In particular, at least one selected from epoxy resins, epoxy-modified polyimide resins, polyimide resins, and phenol resins is preferred.

As described above, since there is a large difference in solubility in specific chemical solutions between the particulate matter and the matrix photosensitive resin after curing treatment, it is necessary to remove the particulate matter dispersed on the surface of the resin layer. When dissolved and removed using a specific chemical solution,
The matrix photosensitive resin, which is sparingly soluble in the specific chemical solution, is hardly dissolved and remains as a base material, forming a clear anchor on the surface of the resin layer. In addition, when using a heat-resistant resin as the particulate material, even if it is a rotary type resin, for example, an epoxy resin that is easily soluble in an oxidizing agent is used as the heat-resistant resin fine powder, and on the other hand, an oxidizing agent is used as the matrix photosensitive resin. It is also possible to use a combination of epoxy resins, which are relatively difficult to dissolve.

As the photosensitive resin liquid in which the particulate matter used in the present invention is dispersed, a photosensitive resin liquid containing no solvent may be used as it is, or a photosensitive resin liquid prepared by dissolving the photosensitive resin in a solvent may be used. Since the resin liquid can have a low viscosity, it is easy to uniformly disperse particulate matter, and it is easy to apply, so it can be used advantageously. As the solvent used to dissolve the photosensitive resin, ordinary solvents can be used, such as methyl ethyl ketone,
Methyl cellosolve, ethyl cellosolve, butyl carpil
--l, butyl cellosolve, tetralin, dimethylformamide, N-methylpyrrolidone, and the like. In addition, in the photosensitive resin liquid serving as the matrix,
Improving the heat dissipation properties of the insulating layer is the first objective.
Fillers with excellent thermal conductivity and electrical insulation properties, such as alumina, beryllia,
Inorganic fillers such as silicon nitride and borosininitride can be added.

Addition of particulate matter to the matrix photosensitive vA fat! , + is preferably in the range of 5 to 350 parts by weight per 11 parts by weight of the matrix photosensitive resin solid content, particularly in the range of a part of the assembly 2() to 201), or in the range of 3 parts by weight or higher with respect to the electroless plating film. This is preferable because it can provide adhesion strength. The reason for this is that if the amount of particulate matter is less than 5 parts by weight, the density of the anchors formed by dissolution and removal will be low, making it impossible to obtain sufficient adhesion strength with the electroless plating film.
This is because if the amount exceeds 50 parts by weight, most of the resin layer will be dissolved, making it difficult to form a sufficient insulating layer.

Next, a method for manufacturing a multilayer printed wiring board according to the present invention will be specifically explained.

According to the present invention, a liquid mixture in which the particulate matter is dispersed in a photosensitive resin liquid serving as a matrix is applied to the rainbow plate on the side of the conductor layer. As this method, various methods such as a roller coating method, a dip coating method, a spray coating method, a spinner coating method, a curtain coating method, and a screen printing method can be applied.

The thickness of the resin layer coated with 1i is usually 20~l()Og
It can be applied to a thickness of about m or even thicker if particularly high insulation is required.

Next, by exposing a predetermined portion of the surface of the photosensitive resin layer coated with light, developing and etching,
Form an insulating layer. In this case, the portion where the resin layer has been removed by development and etching is generally provided with a via hole for connecting the conductor layers.

Substrates used for final IJf include, for example, plastic substrates, ceramic plates, metal substrates, film substrates,
(plates etc. can be used, specifically glass epoxy substrates, glass polyimide substrates, aluminum nano, (plates,
Low-temperature fired ceramic substrate, aluminum nitride laminated, (plate,
Aluminum substrate, iron substrate, polyimide film, (
You can also use a board etc.

Next, (111) the particulate matter present on the surface of the resin layer is dissolved and removed using a specific chemical solution. Alternatively, the surface of the resin layer can be roughened by dipping it in water or by spraying a chemical onto the surface of the resin layer. With the aim of making it effective,
It is advantageous beforehand to lightly remove the surface portions of the resin layer, for example by means of a polishing step using a finely powdered abrasive, such as by boring or liquid honing.

According to Shukan IJJ, after roughening the surface of the resin layer, a conductor layer is formed by electroless plating. Examples of the electroless plating include electroless copper plating, electroless nickel plating,
Examples include electroless tin plating, electroless gold plating, electroless silver plating, etc. In particular, electroless copper plating, electroless '+b
: Preferably, at least one of electrolytic gold plating and electroless gold plating is used.

Note that the electroless plated L can be further subjected to different types of electroless plating or electroplating, or can be coated with solder.

According to the present invention, conductor circuits can be formed using various methods conventionally used for printed wiring boards, such as a method of electroless plating the circuit board and then etching the circuit; It is possible to apply a method of directly forming a circuit when applying electrolytic plating.

Next, the present invention will be explained by examples.

Example 1 (1) Fine epoxy resin powder (manufactured by Toshi, trade name: Treval EP-B) was added to 100 parts by weight of photosensitive polyimide resin (manufactured by Roke Kasei Kogyo Co., Ltd., trade name: T-14) solid content. were blended at a ratio of 120 parts by weight, and while adding N-methylpyrrolidone solvent, the viscosity was mixed with a homodisper disperser.
Adjust to ff5000cpS, then knead with a Miki roll to form an insulating layer phase 11).

(2) Next, the insulating layer phase face is placed on the printed wiring board obtained by photoetching the surface of the copper clad laminate (glass cloth base material polyimide resin) using a conventional method.
1000rpm) and soaked in water for 6 minutes.
After being left at room temperature for 0 minutes, it was dried at 80° C. for 10 minutes to form an insulating layer with a thickness of 60 ILm.

(3) Next, a photomask in which a black circle of 100 mφ was formed was closely attached to this, and the film was exposed for 30 seconds using an ultra-high pressure mercury lamp. This was mixed with N-methylpyrrolidone-methanol (
3:1) A via hole of 10 gmφ was formed on the printed wiring board by developing with a mixed solvent for 1 minute. Next, this wiring board was exposed to light using an ultra-high pressure mercury lamp for 5 minutes, and then heat-treated at 200° C. for 30 minutes to completely cure the insulating layer.

(4) The surface of this insulating layer was lightly polished with a rotary brush polisher using #tono alumina fine powder polishing material.
After roughening the surface of the insulating layer by immersing it in an oxidizing agent consisting of 800 g/fL aqueous solution of chromic acid (CrO:l) at 60°C for 2 minutes, a neutralizing solution (manufactured by Sibley, trade name: PM950) was applied. Soaked in water and washed with water.

(5) Add a palladium catalyst (manufactured by Sibley, product name: Catabosite 4) to the printed wiring board with a roughened surface of the insulating layer.
4) to activate the surface of the insulating layer, and then immersed in an electroless nickel plating solution for additive method (World Metal, trade name: Niboron-5) for 3 hours until the thickness of the plated film was approximately 10 pm electroless Nilacel plating was applied.

(6) The adhesion strength between the insulating layer and the nickel plating film of the multilayer printed wiring board manufactured as described below is 111.
The pull strength was 1.5 kg/mrn', and a heat resistance test was conducted in which the surface of the multilayer printed wiring board was brought into close contact with a hot plate whose surface temperature was maintained at 300°C and heated for 0 minutes. No abnormalities were observed after the test.

Example 2 (1) Epoxy resin (manufactured by Mitsui Petrochemical Industries, product name: T
A-1800)? Harden by drying in an S-air dryer at 150°C for 1 hour, then at 180°C for 4 hours, coarsely crush the hardened epoxy resin, and then freeze it with liquid nitrogen. The mixture was pulverized using an f-speed jet pulverizer and further classified using an air classifier to produce epoxy resin fine powder with an average particle size of 1.6 Bm.

Photosensitive polyimide resin (manufactured by Hitachi Chemical, product name: T
-14) Blend the above-mentioned epoxy resin fine powder at a ratio of + [10 parts by weight to the solid content + 00 weight y11,8'8, and further add the N-methylpyrrolidone solution while measuring the viscosity using a homodisper disperser. The mixture was adjusted to 5000 cps, and then kneaded using a three-piece roll to obtain an insulating layer phase face.

(2) This insulating layer layer was coated on a printed wiring board in the same manner as in Example 1 to form an insulating layer with a thickness of 60 μm.

(3) After forming via holes in this insulating layer in the same manner as in Example 1, the insulating layer was completely cured, the surface was roughened, and electroless nickel plating was applied.

The adhesion strength between the insulating layer and the nickel plating film of the multilayer printed wiring board thus obtained was 1.7k in terms of pull strength.
g/mba.

(Effects of the Invention) As described above, according to the multilayer printed wiring board and the manufacturing method thereof of the present invention, the adhesion between the conductive circuit made of the electroless plated film and the insulating layer is extremely excellent, and the heat resistance is high. A multilayer printed wiring board can be obtained, which is extremely useful in industry.

Claims (1)

[Claims] 1) A structure in which a conductor circuit made of an electroless plating film and an insulating layer made of a resin with excellent heat resistance are alternately laminated, and the insulating layer is resistant to a specific chemical solution. The photosensitive resin, which is poorly soluble in water, contains particulate matter that is soluble in the chemical solution, and the interface with the electroless plating film is a result of the particulate matter being dissolved by the specific chemical solution. A multilayer printed wiring board having a recess formed therein, and an anchor of an electroless plating film formed in the recess. 2) The multilayer printed wiring board according to claim 1, wherein the photosensitive resin is at least one selected from epoxy resin, epoxy-modified polyimide resin, polyimide resin, and phenol resin. 3) The multilayer printed wiring board according to claim 1 or 2, wherein the particulate matter is at least one of heat-resistant resin fine powder and inorganic fine particles that have been cured in advance. 4) The multilayer printed wiring board according to any one of claims 1 to 3, wherein the particulate matter has an average particle size of 10 μm or less. 5) The multilayer printed wiring board according to any one of claims 1 to 4, wherein the particulate matter is blended in an amount of 5 to 350 parts by weight based on 100 parts by weight of the photosensitive resin solid content. 6) The specific chemical solution contains at least one selected from chromic acid, chromate, permanganate, and ozone.
The multilayer printed wiring board according to any one of claims 1 to 5, which contains seeds. 7) The multilayer printed wiring board according to any one of claims 1 to 6, wherein the electroless plating is at least one of electroless copper plating, electroless nickel plating, and electroless gold plating. 8) A method for manufacturing a multilayer printed wiring board, comprising at least the following steps (a) to (d). (a) A liquid mixture in which particulate matter soluble in the chemical liquid is dispersed in an uncured photosensitive resin whose properties after curing are poorly soluble in a specific chemical liquid is applied to a substrate having a conductor layer. (b) After exposing a predetermined location on the surface of the photosensitive resin, developing and etching it; (c) Using the specific chemical solution to form a photosensitive resin; A step of dissolving and removing the particulate matter existing on the surface portion and roughening the surface of the resin layer; (d) A step of forming a conductor layer by electroless plating.