JP3804809B2 - Manufacturing method of multilayer printed wiring board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a multilayer printed wiring board having through holes.
[0002]
[Prior art]
As an interlayer connection method for a multilayer printed wiring board, a method of drilling holes and plating through holes is generally used. When drilling with a drill in the process of forming this through hole, the drill rotates at a high speed, so that frictional heat is generated, and the shavings and insulating resin are softened. This softened resin is reattached to the side surface of the hole, so that a so-called smear that the conductor circuit and the through-hole plating at the attached portion are not connected may occur, resulting in poor conduction.
Therefore, desmear treatment for removing such smear is necessary. However, as the desmear treatment liquid, it is possible to use concentrated sulfuric acid, chromic acid, alkaline permanganate, etc., as disclosed in JP-A-54-144968, This is known from Japanese Patent Application Laid-Open No. 62-104197. Further, a desmear method using plasma without using such a chemical is known from Japanese Patent Application Laid-Open No. 63-311797.
[0003]
[Problems to be solved by the invention]
In the conventional technology, when using concentrated sulfuric acid, chromic acid, or alkali permanganate as desmear treatment liquid, these liquids are chemicals that fall under the specified chemical substances of the Industrial Safety and Health Act, and are handled for safety. In addition, there is a problem that the management must be strictly controlled because a regular medical examination is required for the handler. Furthermore, since concentrated sulfuric acid has a strong water absorption, sufficient concentration control is required.
In addition, the method of using plasma for desmear processing has to perform input / depressurization / plasma treatment / decompression release / removal, and there is a problem that the working efficiency is extremely low.
[0004]
An object of this invention is to provide the manufacturing method of the multilayer printed wiring board excellent in safety | security and excellent in efficiency.
[0005]
[Means for Solving the Problems]
The method for producing a multilayer printed wiring board according to the present invention is a method for producing a multilayer printed wiring board in which a copper-clad glass epoxy laminated board having an inner layer circuit is drilled to perform desmear treatment, through-hole plating, and circuit formation. In the treatment, a solution comprising an amide solvent and an alcohol solvent solution of an alkali metal hydroxide is used.
[0006]
The desmear liquid used in the present invention is prepared by blending and mixing an amide solvent and an alcohol solvent solution of an alkali metal hydroxide.
Examples of the amide solvent used in the present invention include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N, N, N ′, N′-. Examples include tetramethylurea, 2-pyrrolidone, N-methyl-2-pyrrolidone, carbamic acid ester, and the like. Among these, N, N-dimethylformamide, N, N-dimethylacetamide, and N-methyl-2-pyrrolidone are particularly preferable because they have an effect of swelling the epoxy resin cured product and the solubility of the decomposition product is good. . These solvents can be used in combination.
[0007]
Moreover, you may use together with the other solvent represented by the ketone solvent, the ether solvent, etc.
Examples of ketone solvents that can be used together include acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, methyl isobutyl ketone, 2-heptanone, 4-heptanone, diisobutyl ketone, and cyclohexanone.
Examples of ether solvents that can be used in combination here include dipropyl ether, diisopropyl ether, dibutyl ether, anisole, phenetole, dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether.
[0008]
Examples of the alkali metal hydroxide used in the present invention include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide. Of these, sodium hydroxide and potassium hydroxide are particularly preferable because the decomposition rate of the cured epoxy resin is high.
[0009]
Examples of the alcohol solvent used in the present invention include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, iso-butanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, iso-pentyl alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-petanol, 4-methyl 2-petanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 4-methylcyclo Hexanol, Tylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol Ethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4 -Butanediol, 2,3-butanediol, 1 5 Bae Ntanjioru, glycerin, dipropylene glycol or the like. Among these, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (molecular weight 200 to 400), and 1,2-propanediol have high solubility of alkali metal hydroxide, and have a high boiling point and are easy to handle. Therefore, it is particularly preferable. Several kinds of these solvents can be used in combination.
[0010]
In the desmear treatment liquid used in the present invention, the composition of the alkali metal hydroxide alcohol solvent solution with respect to the amide solvent is preferably 50 to 99% by weight of the amide solvent with respect to the alcohol solvent of the alkali metal hydroxide. The range is 1 to 50% by weight of the solution.
If the concentration of the amide solvent is less than 50% by weight, the swellability of the epoxy cured product and the solubility of the decomposed product are not preferable, and if it exceeds 99% by weight, the concentration of the alkali metal hydroxide decreases as a result. Therefore, the decomposition rate of the cured epoxy resin is reduced, which is not preferable.
[0011]
The alkali metal hydroxide concentration of the alcohol solvent solution is preferably in the range of 0.5 wt% to 40 wt%. If it is less than 0.5% by weight, the decomposition rate of the cured epoxy resin decreases, which is not preferable. If it exceeds 40% by weight, the alkali metal hydroxide cannot be completely dissolved in the alcohol solvent.
[0012]
A surfactant or the like can be added to the desmear liquid thus obtained.
In addition, the desmear liquid can be heated to around 90 ° C. during the desmear treatment.
As the desmearing method, the object to be treated can be immersed in a desmear liquid to generate bubbles or to vibrate by ultrasonic waves. Moreover, spray etc. can also be used even if it does not immerse in a liquid.
[0013]
The mixed solution comprising the amide solvent used as the desmear liquid and the alcohol solvent solution of the alkali metal hydroxide of the present invention does not correspond to the specific chemical substance, and the processing conditions are a liquid temperature of 60 ° C. and an immersion time. It takes about 10 minutes, and continuous charging is possible.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0015]
【Example】
[0016]
Example 1
Circuit processing was performed on both sides of MCL-E-67 (Hitachi Chemical Industry Co., Ltd., trade name), a double-sided copper-clad glass epoxy laminate with a thickness of 0.2 mm, and a glass epoxy prepreg with a thickness of 0.1 mm. GEA-E-67N (Hitachi Kasei Kogyo Co., Ltd., trade name) and NDGK-18 (trade name, manufactured by Nippon Electrolytic Co., Ltd.), which is a copper foil with a thickness of 18 μm, are bonded by a press. Using a drill with a diameter of 0.8 mm, using a 0.1 mm aluminum plate on the upper plate and a 1.0 mm paper phenol laminate on the lower plate, a hole with a rotation speed of 70000 rpm and a feed rate of 3 m / min Dawned.
As a desmear liquid, a mixed solution having the following composition was prepared.
・ N, N-dimethylformamide ... 80wt%
・ Sodium hydroxide in ethylene glycol solution 20% by weight
(Sodium hydroxide concentration: 20% by weight)
The perforated glass epoxy laminate was immersed in a desmear solution at 60 ° C. and shaken lightly for 10 minutes. Thereafter, it was washed with running water for 10 minutes, plated, and a circuit was formed.
[0017]
Example 2
As a desmear liquid, a mixed solution having the following composition was prepared.
N, N-dimethylformamide 80% by weight,
-Potassium hydroxide in ethylene glycol solution 20% by weight
(Potassium hydroxide concentration: 20% by weight)
The perforated glass epoxy laminate produced in Example 1 was immersed in a desmear solution at 60 ° C. and shaken lightly for 10 minutes. Thereafter, it was washed with running water for 10 minutes, subjected to desmear treatment, plated, and a circuit was formed.
[0018]
Example 3
As a desmear liquid, a mixed solution having the following composition was prepared.
・ N, N-dimethylacetamide ... 80% by weight
・ Sodium hydroxide in ethylene glycol solution 20% by weight
(Sodium hydroxide concentration: 20% by weight)
The perforated glass epoxy laminate produced in Example 1 was immersed in a desmear solution at 60 ° C. and shaken lightly for 10 minutes. Thereafter, it was washed with running water for 10 minutes, subjected to desmear treatment, plated, and a circuit was formed.
[0019]
Example 4
As a desmear liquid, a mixed solution having the following composition was prepared.
・ N-methylpyrrolidone ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 80% by weight
・ Sodium hydroxide in ethylene glycol solution 20% by weight
(Sodium hydroxide concentration: 20% by weight)
The perforated glass epoxy laminate produced in Example 1 was immersed in a desmear solution at 60 ° C. and shaken lightly for 10 minutes. Thereafter, it was washed with running water for 10 minutes, subjected to desmear treatment, plated, and a circuit was formed.
[0020]
Example 5
As a desmear liquid, a mixed solution having the following composition was prepared.
・ N, N-dimethylformamide ... 80wt%
・ Diethylene glycol solution of sodium hydroxide ... 20% by weight
(Sodium hydroxide concentration: 20% by weight)
The perforated glass epoxy laminate produced in Example 1 was immersed in a desmear solution at 60 ° C. and shaken lightly for 10 minutes. Thereafter, it was washed with running water for 10 minutes, subjected to desmear treatment, plated, and a circuit was formed.
[0021]
Example 6
As a desmear liquid, a mixed solution having the following composition was prepared.
・ N, N-dimethylacetamide ... 80% by weight
・ Sodium hydroxide in triethylene glycol solution: 20% by weight
(Sodium hydroxide concentration: 15% by weight)
The perforated glass epoxy laminate produced in Example 1 was immersed in a desmear solution at 60 ° C. and shaken lightly for 10 minutes. Thereafter, it was washed with running water for 10 minutes, subjected to desmear treatment, plated, and a circuit was formed.
[0022]
Example 7
As a desmear liquid, a mixed solution having the following composition was prepared.
・ N, N-dimethylformamide ... 80wt%
・ Sodium hydroxide in tetraethylene glycol solution ... 20% by weight
(Sodium hydroxide concentration: 15% by weight)
The perforated glass epoxy laminate produced in Example 1 was immersed in a desmear solution at 60 ° C. and shaken lightly for 10 minutes. Thereafter, it was washed with running water for 10 minutes, subjected to desmear treatment, plated, and a circuit was formed.
[0023]
Example 8
As a desmear liquid, a mixed solution having the following composition was prepared.
・ N, N-dimethylformamide ... 80wt%
・ Sodium hydroxide in polyethylene glycol solution: 20% by weight
(Sodium hydroxide concentration: 10% by weight, polyethylene glycol content: 200)
The perforated glass epoxy laminate produced in Example 1 was immersed in a desmear solution at 60 ° C. and shaken lightly for 10 minutes. Thereafter, it was washed with running water for 10 minutes, subjected to desmear treatment, plated, and a circuit was formed.
[0024]
Example 9
As a desmear liquid, a mixed solution having the following composition was prepared.
・ N, N-dimethylacetamide ... 80% by weight
-1,2-propanediol solution of sodium hydroxide ... 20% by weight
(Sodium hydroxide concentration: 15% by weight)
The perforated glass epoxy laminate produced in Example 1 was immersed in a desmear solution at 60 ° C. and shaken lightly for 10 minutes. Thereafter, it was washed with running water for 10 minutes, subjected to desmear treatment, plated, and a circuit was formed.
[0025]
Example 10
Instead of the glass epoxy prepreg used in Example 1, AS-3000 (Hitachi Chemical Industry Co., Ltd., trade name), which is an epoxy adhesive film having a thickness of 0.05 mm, was used. .
The perforated glass epoxy laminate was immersed in the desmear solution used in Example 1 at 60 ° C. and shaken lightly for 10 minutes. Thereafter, it was washed with running water for 10 minutes, subjected to desmear treatment, plated, and a circuit was formed.
[0026]
Example 11
As the desmear liquid, a mixed solution having the following composition was used.
・ N, N-dimethylformamide ... 80wt%
・ Polyethylene glycol solution of potassium hydroxide ... 20% by weight
(Potassium hydroxide concentration: 20% by weight, molecular weight of polyethylene glycol: 200) The perforated glass epoxy laminate produced in Example 1 was immersed in a desmear solution at 60 ° C. and gently shaken for 10 minutes. Thereafter, it was washed with running water for 10 minutes, subjected to desmear treatment, plated, and a circuit was formed.
[0027]
Comparative Example 1
The glass epoxy laminated board perforated in Example 1 was immersed in dimethylformamide at 60 ° C. and shaken lightly for 10 minutes. Thereafter, it was washed with running water for 10 minutes and subjected to desmear treatment.
[0028]
(Cross section observation)
The cross-sectional observation inside the through-hole is made by casting the produced glass epoxy laminate with an epoxy-based resin, polishing a sample until the through-hole portion can be observed as a cross-section, and at a magnification of 200 times the microscope. Observed.
As a result, in all of the examples, plating voids, peeling, etc. were not confirmed in the through hole, and smear was not confirmed in the connection portion with the inner layer circuit, and in the comparative example, there was a void in the through hole. .
[0029]
(Hot oil test)
It was immersed in hot oil heated to 260 ° C. for 10 seconds and immersed in water at 25 ° C. for 20 seconds, and this was defined as one cycle. In all the examples, the connection resistance did not decrease even after the 30-cycle test, and the connection reliability was the same as that obtained after desmear treatment using an alkali permanganate.
In the comparative example, disconnection occurred after 10 cycles.
[0030]
【The invention's effect】
The mixed solution comprising the amide solvent used as the desmear liquid and the alcohol solvent solution of the alkali metal hydroxide of the present invention does not correspond to the specific chemical substance, and the processing conditions are a liquid temperature of 60 ° C. and an immersion time. It takes about 10 minutes, and can provide a method for producing a multilayer printed wiring board that is excellent in safety and efficiency.

Claims (5)

In a method of manufacturing a multilayer printed wiring board in which a copper-clad glass epoxy laminated board having an inner layer circuit is drilled, desmeared, through-hole plated, and circuit-formed, in the desmeared process, an amide solvent and an alkali metal hydroxide are used. A method for producing a multilayer printed wiring board, wherein a solution comprising an alcohol solvent solution is used. 2. The method for producing a multilayer printed wiring board according to claim 1, wherein the amide solvent is any one of N, N-dimethylformamide, N, N-dimethylacetamide, and N-methyl-2-pyrrolidone. 3. The method for producing a multilayer printed wiring board according to claim 1, wherein the alkali metal hydroxide is any one of sodium hydroxide and potassium hydroxide. The multilayer solvent according to any one of claims 1 to 3, wherein the alcohol solvent is one of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, and 1,2-propanediol. A method for manufacturing a printed wiring board. The amide solvent is 50 to 99% by weight, and the alcohol solvent solution of alkali metal hydroxide (alkali metal hydroxide concentration 0.5 to 40% by weight) is in the range of 1 to 50% by weight. The manufacturing method of the multilayer printed wiring board in any one of Claims 1-4.