JPS6137800B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing high density printed circuit boards using novel printed circuit board materials capable of high density.

(Prior Art and its Problems) The current method of manufacturing printed circuit boards using copper-clad laminates requires a large number of steps, and there is a limit to high density due to side etching. Recently, there has been a demand for higher density electronic components, and higher density printed circuit boards are desired.

In order to meet the above requirements, the present inventors have developed a method for manufacturing a printed circuit board that is simple and capable of increasing density.
This was proposed in Japanese Patent Application Laid-Open No. 52-23664. however,
This method has the disadvantage that, in particular, when the conductor thickness is increased, the conductor becomes thicker during plating, resulting in a decrease in resolution.

(Means for Solving the Problems) As a result of intensive research in order to solve the above-mentioned drawbacks, the inventors of the present invention have found that by using a photoresist in combination and making it act as a wall to prevent the thickening of the plating,
The inventors discovered that a high-density printed circuit board can be manufactured regardless of the conductor thickness, and completed the present invention.

(Structure of the Invention) That is, the present invention includes a substrate or a substrate on which a polymer layer is applied, and iron, cobalt, nickel, copper, etc. formed on the substrate or on the polymer layer applied on the substrate. silver, gold, bismuth, antimony, tin, aluminum, cadmium, zinc,
Film thickness 50-3000Å selected from lead, selenium, indium, tellurium, germanium, and their alloys
A method for manufacturing a printed circuit board using a material for a printed circuit board comprising a thin metal layer that can be dispersed and removed by applying energy, and a photoresist layer formed on the thin metal layer, the photoresist being In the case of a negative type, (a) the thin metal layer and the photoresist layer are applied with an amount of energy sufficient to produce a pattern, either simultaneously or sequentially, using a positive mask of the desired circuit pattern; producing a circuit pattern in the photoresist layer and a negative pattern of the circuit in the photoresist layer, and subsequently developing and dissolving the soluble portion of the photoresist layer to expose the circuit pattern consisting of a thin metal layer underlying the soluble portion; , (b) applying an amount of energy sufficient to pattern the photoresist layer using a positive tone mask of the desired circuit pattern to produce a negative pattern of the circuit in the photoresist layer; After developing and dissolving the soluble portion of to expose the thin metal layer below the soluble portion,
Again, using the positive type mask, a sufficient amount of energy is applied to produce a pattern in the thin metal layer to produce a circuit pattern in the thin metal layer. ’) Pattern the metal thin layer and the photoresist layer in order using a positive mask with the desired circuit pattern for patterning the metal thin layer and a negative mask with the desired circuit pattern for patterning the photoresist layer. A sufficient amount of energy is applied to produce a circuit pattern in the thin metal layer and a negative pattern of the circuit in the photoresist layer, followed by developing and dissolving the soluble portions of the photoresist layer. or (b') applying a sufficient amount of energy to create a pattern in the photoresist layer using a negative tone mask of the desired circuit pattern. A negative pattern of the circuit is produced in the photoresist layer, and then the soluble portion of the photoresist layer is developed and dissolved to expose the thin metal layer underlying the soluble portion, using a positive tone mask of the desired circuit pattern. a circuit pattern in the thin metal layer by applying an amount of energy sufficient to create a pattern in the thin metal layer; This is a method for manufacturing a printed circuit board characterized by applying metal plating.

In this way, by using photoresist as a wall to prevent plating from thickening, it became possible for the first time to manufacture high-density printed circuit boards regardless of conductor thickness.

The photoresist used in the present invention includes:
Although both negative and positive types can be used, negative type is preferred because the same positive mask can be used for patterning the thin metal layer and the photoresist. In the case of a negative type, it is also possible to pattern a thin metal layer and expose it from the substrate side using the patterned thin metal layer as a mask. Positive photoresists include diazo photoresists, azide photoresists, and epoxy photoresists, while negative photoresists include polyvinylcinnamic acid photoresists, tetrazonium salt photoresists, and bisazide photoresists. Examples include photoresists, vinyl monomer or divinyl monomer photoresists, and epoxy photoresists. These photoresists become solid after coating and drying, and have excellent chemical resistance and
Those with excellent heat resistance, adhesion, and electrical properties are preferred, and epoxy photoresists are particularly preferred. These can be applied by dissolving them in a suitable solvent to obtain a desired film thickness. A more preferable range of film thickness is 1 to 50μ.

Metal thin layers that can be used in the present invention include iron,
These include cobalt, nickel, copper, silver, gold, bismuth, antimony, tin, aluminum, cadmium, zinc, lead, selenium, indium, tellurium, germanium, and alloys thereof. These thin metal layers can be deposited by vacuum deposition, by any convenient equipment,
It can be formed by methods such as sputtering, cool sputtering, and ion plating, and may have a single layer, or may have a multilayer structure of two or more layers as necessary. The preferred film thickness is 50 to 3000 Å, particularly 100 to 1000 Å. The exposed portions of the thin layer made of the metal having such a thickness can be dispersed and removed by applying energy as described later.

The polymer layer used in the present invention is preferably one that is resistant to thermal decomposition. Further, those having excellent adhesion to the substrate such as a laminate plate and the thin metal layer used are particularly suitable. The above-mentioned polymers can be either thermoplastic or thermosetting, but thermosetting ones are particularly preferred. Polymers that can be suitably used in the present invention include epoxy resins, copolymers of methyl methacrylate and methyl acrylate, polyurethane, polyvinylidene chloride, polyvinyl acetate, polyvinyl butyral, and copolymers of vinylidene chloride and vinyl acetate or acrylonitrile. ,
Copolymers of vinyl chloride and vinyl acetate, polycarbonates, polyamides, polyimides, polyesters, cellulose triacetate,
Examples include a copolymer of styrene and acrylonitrile, a copolymer of acrylonitrile, butadiene, and styrene, and in the case of a thermosetting type, an appropriate initiator or curing agent may be added. These can be applied by dissolving them in a suitable solvent to obtain a desired film thickness. A more preferable range of film thickness is 1 to 100μ.

Substrates that can be used in the present invention can be found in a wide variety of ways. The substrate may be an inorganic material such as silicate glass, ceramic, or mica, or may be made of polyester, polyimide, polyamide, cellulose acetate,
Although organic materials such as polystyrene, polyethylene, and polypropylene may be used, a laminate of phenol resin or epoxy resin using a paper or glass cloth base material is particularly preferably used.

As a method for imparting a pattern to the printed circuit board material according to the present invention, the pattern may be formed on the metal thin layer and the photoresist at the same time, or it is also possible to form the pattern separately. Methods for forming a pattern on a thin metal layer include exposure using a mask or scanning with image-modulated energy. energy is applied. Types of energy include radiant energy and particle energy, and pulsed energy is more preferable. Examples include flash lamps, infrared lamps, lasers, and electron beams. Methods for forming patterns on photoresist include exposing using a mask, scanning energy modulated in an image, or exposing a pattern from the substrate side after forming a pattern on a thin metal layer. can be,
A sufficient amount of energy is applied to create a difference in solubility between the exposed and unexposed portions of the photoresist layer in a suitable solvent. Types of energy include radiant energy and particle energy, such as ultraviolet lamps, flash lamps, lasers, and electron beams. After exposure in this manner, in the case of a normal photoresist, it is immediately developed with a suitable solvent. In the case of a positive type epoxy photoresist, it is heat treated and then developed with a suitable solvent.

In the present invention, a method is particularly preferably used in which a sufficient amount of energy is applied to the metal thin layer and the photoresist layer to form a pattern, and then the soluble portion of the photoresist layer is developed and dissolved.

The conductive metal plating method used in the present invention includes electroplating and electroless plating, and these methods can be used alone or in combination. Examples of the conductive metal include copper, silver, and nickel, but copper is generally used, and plating is usually performed by a known method.

In addition, in order to further improve reliability, after metal plating as necessary, heat treatment or gold, tin,
Treatments include providing a protective layer of solder or polymer.

In order to further clarify the aspects of the present invention, as follows:
Although the present invention will be described with reference to examples, the present invention is not limited to the following examples and can be modified in various ways.

Example 1 An epoxy adhesive “XA-564” manufactured by Postik was applied on an epoxy resin laminate using a glass cloth base material.
-4" to a thickness of 25μ after drying.
After heating at 180° C. for 30 minutes, 100 Å of copper and then 100 Å of nickel were deposited. In addition, 20 parts by weight of epoxy resin AER-661 manufactured by Asahi Kasei Corporation (bisphenol A type, epoxy equivalent 45.0 to 500), 17.3 parts by weight of 4-aminomethyl-1,8-diaminooctane, and 10.6 parts by weight of acrylonitrile were reacted. 2.659 parts by weight of product, 6.32 parts by weight of carbon tetrabromide and 40 parts by weight of chloroform
A photosensitive epoxy resin composition consisting of parts by weight was coated to a thickness of 35 μm after drying. The thus obtained printed circuit board material was exposed to light through a positive circuit pattern mask using a 1300 W xenon flash lamp with a pulse width of 100 microseconds to obtain a metal thin film pattern. Next, an inversion mask (negative mask) of the above circuit pattern mask
After exposure for 2 minutes using a 2KW mercury lamp through the wafer, heating at 110℃ for 20 minutes and developing with acetone, the exposed areas of the photosensitive epoxy resin composition are washed out and the patterned metal thin layer is exposed. did. On the thin metal plate, 0.03 mol/liter of copper sulfate, 0.125 mol/liter of sodium hydroxide, 0.08 mol/liter of formaldehyde, 0.36 mol/liter of tetrasodium ethylenediamine tetraacetate, and sodium cyanide were added.
Copper was electrolessly plated to a thickness of 35 μm at 70° C. using an electroless copper plating solution containing 0.004 mol/liter and 1 liter of water to obtain a printed circuit board having a fine pattern of 10 lines/mm.

Example 2 An epoxy adhesive "XA-564-4" manufactured by Bostik Co., Ltd. was applied on a polyimide film to a thickness of 15 μm after drying, heated at 180° C. for 20 minutes, and then 50 μm of copper and 350 μm of tin were evaporated. did. On top of that, after drying, a photosensitive resin "Topron" manufactured by Tokyo Ohka Co., Ltd., which is mainly composed of polyamide and divinyl monomer, is applied.
It was applied to a thickness of 30μ. The printed circuit board material thus obtained was exposed to light in the same manner as in Example 1 to obtain a metal thin film pattern. Then,
After exposing the substrate side to light for 2 minutes using a 2KW mercury lamp, the film was developed using Topron developer, and the non-exposed areas of the photosensitive resin were washed out, exposing the metal thin film. After that, copper was electrolessly plated to a thickness of 2μ using Okuno Chemical Co., Ltd.'s electroless copper plating liquid "TMP-100", and then an electroplating liquid containing 200 g of copper sulfate and 45 g of sulfuric acid was used to plate the copper at a current density of
Copper was electroplated to a thickness of 28 μm at 4 A/dm ² and 25° C., and then heat treated at 180° C. for 60 minutes to obtain a printed circuit board having a fine pattern of 10 lines/mm.

Example 3 Polyurethane “Hamakoran VK-1080” manufactured by Yokohama Rubber Co., Ltd. was applied on a polyester film.
Using N'-dimethylformamide solvent, it was coated to a thickness of 30 μm after drying, heated at 100° C. for 10 minutes, and then nickel was deposited to a thickness of 200 μm. On top of that, a polyvinyl cinnamic acid photoresist "TPR" manufactured by Tokyo Ohka Co., Ltd. was applied to a thickness of 20 μm after drying. A positive circuit pattern mask is passed through the printed circuit board material obtained in this way.
After exposure for 2 minutes using a 2KW mercury lamp,
When developed using a TPR developer, the unexposed areas of the photoresist were washed out, exposing the metal thin film. Thereafter, the metal thin film was patterned by exposure in the same manner as in Example 1 through the same positive type circuit pattern mask. Next, copper sulfate 200g/, sulfuric acid 45
A printed circuit board having a fine pattern of 10 lines/mm was obtained by electroplating copper to a thickness of 20 μm using an electroplating solution of 10 g/mm.

Claims (1)

[Claims] 1. A substrate or a substrate on which a polymer layer is applied, and iron, cobalt, nickel, or the like formed on the substrate or on the polymer layer applied on the substrate.
Metal thin film selected from copper, silver, gold, bismuth, antimony, tin, aluminum, cadmium, zinc, lead, selenium, indium, tellurium, germanium, and alloys thereof that can be dispersed and removed by applying energy to a thickness of 50-3000 Å A method for manufacturing a printed circuit board using a printed circuit board material comprising a layer of metal and a photoresist layer formed on the thin metal layer, the method comprising: (a) a desired The circuit pattern is formed in the thin metal layer and the photoresist layer by applying an amount of energy sufficient to produce a pattern to the thin metal layer and the photoresist layer, either simultaneously or sequentially using a positive tone mask of the circuit pattern. (b) creating a negative pattern of the circuit and subsequently developing and dissolving the soluble portion of the photoresist layer to expose the circuit pattern consisting of a thin metal layer underlying the soluble portion; or (b) creating a positive pattern of the desired circuit pattern. A pattern mask is used to apply a sufficient amount of energy to pattern the photoresist layer to produce a negative pattern of circuitry in the photoresist layer, followed by developing and dissolving the soluble portions of the photoresist layer. After exposing the thin metal layer underneath the part,
Again using the positive mask, a sufficient amount of energy is applied to create a pattern in the thin metal layer to create a circuit pattern in the thin metal layer.However, if the photoresist is also positive, ( a)′ For patterning the metal thin layer, use a positive mask with the desired circuit pattern, and for patterning the photoresist layer, use a negative mask with the desired circuit pattern. A sufficient amount of energy is applied to create a pattern to create a circuit pattern in the thin metal layer and a negative pattern of the circuit in the photoresist layer, followed by developing and dissolving the soluble portions of the photoresist layer. (b) applying a sufficient amount of energy to create a pattern in the photoresist layer using a negative-tone mask of the desired circuit pattern; to produce a negative circuit pattern in the photoresist layer, and then develop and dissolve the soluble portion of the photoresist layer to expose the thin metal layer underlying the soluble portion, and then apply a positive tone mask of the desired circuit pattern. applying an amount of energy sufficient to produce a pattern in the thin metal layer using a circuit to produce a circuit pattern in the thin metal layer; A method for producing a printed circuit board, characterized by applying metal plating thereon.