JPH02266594A - Manufacture of multilayer printed wiring board - Google Patents

Abstract

PURPOSE:To obtain favorable haloing resistance and enough adhesion and heat resistance and to see that faults and chips do not occur at the copper rough face by cathodically electrolyzing a both-side copper plated laminate in specific aqoueous solution, and forming a circuit with a specific photosensitive etching resist layer as a mask, and using it as a multilayer board without separating the mask. CONSTITUTION:With the both-side copper plated laminate as a cathode, electrolysis is done aqueous solution which includes diethylenetriamine pentaacetic acid and/or ethylenediaminetetraacetic acid and copper ions so as to form minute copper rough face at the copper surface. Next, a photosensitive etching resist layer consisting of polymers having epoxy radicals and photosensitive radicals is provided selectively so as to form an inner layer circuit 12, and then without removing a resist layer 13, an inner layer plate 1, wherein the inner layer circuit is formed, a bonding sheet 4, and an outer layer copper foil 5 are laminated integrally. The rough face, which is formed by this, becomes the copper rough face which is uniformly and minutely granular-ciliary, and wherein hydrochloric acid resistance is extremely strong, and adhesion and haloing resistance improve.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a multilayer printed wiring board that is excellent in rolling resistance, heat resistance, and adhesion.

(Conventional technology) Conventionally, when manufacturing multilayer printed wiring boards, blackening treatment is applied to the silver foil surface in order to maintain adhesion between the copper foil surface of the inner layer circuit and the bonding sheet, and to maintain heat resistance during solder reflow. is being carried out. The blackening treatment is to immerse the inner layer board on which the circuit has been formed in chlorite alkaline solution at 80 to 100°C to form a rough surface consisting of a black oxide film of copper on the copper foil surface.

However, the copper oxide film produced by blackening treatment has essentially very low acid resistance, especially hydrochloric acid resistance, and in recent years this has rapidly become a problem.High-density multi-layer coatings for surface mounting with small-diameter through-holes and landless through-holes When a board is immersed in an aqueous solution containing hydrochloric acid used for etchback after the through-hole drilling process or pre-activation treatment for the electroless copper plating process, the bonding interface between the resin and copper in the through-hole area is exposed. Do it! ;i The oxide film is eroded and so-called "lowing" occurs, resulting in problems of poor adhesion or delamination.

To improve such haloing, ■ remove the oxide film with an aqueous solution containing ammonium acetate, copper acetate, ammonium chloride, and aqueous ammonia, or an aqueous solution containing trisodium phosphate, sodium hydroxide, and sodium chlorite. There are two methods: (2) using double-sided treated copper foil that has been electrically roughened in advance.

However, although the former method (2) improves haloing resistance compared to the blackening treatment method, it essentially still has weak acid resistance, and the adhesion strength with copper and heat resistance are even lower than the blackening treatment method. It was inferior. Furthermore, the latter method (2) has the disadvantage of being extremely expensive.

Therefore, a method is proposed in which an inner layer board or a copper-clad laminate with an inner layer circuit formed thereon is subjected to cathodic electrolysis in an aqueous solution containing diethylenetriaminepentaacetic acid and/or ethylenediaminetetraacetic acid and copper ions to form a fine copper surface on the copper surface. was proposed. However, with this method, haloing resistance,
Although it improves adhesion, heat resistance, etc., it has the disadvantage that the rough copper surface is easily chipped. That is, when the copper foil pattern is etched after its surface has been roughened and the dry film of the mask is stripped off, the surface of the fine copper layer is exposed and scratches are likely to occur, and the roughened copper surface is easily chipped off due to handling. If the rough copper surface is missing, the adhesion with the resin will deteriorate,
Heat resistance also decreases.

Furthermore, these drawbacks result in lower yields and higher costs.

(Problems to be Solved by the Invention) The present invention has been made to eliminate the above-mentioned drawbacks, and has good haloing resistance, sufficient adhesion and heat resistance, and can be used to prevent scratches on copper surface. It is an object of the present invention to provide a method for manufacturing a multilayer printed wiring board and an inner layer board for multilayer printed wiring that is free from defects and defects. Another object of the present invention is to provide a method for manufacturing a multilayer printed wiring board and an inner layer board for multilayer printed wiring, which can omit the step of peeling off the etching resist.

[Structure of the Invention] (Means for Solving the Problem) As a result of intensive research to achieve the above object, the present inventors have developed a double-sided copper-clad laminate using diethylenetriaminepentaacetic acid and/or ethylenediaminetetraacetic acid. In addition, the above object can be achieved by cathodic electrolysis in an aqueous solution containing copper ions, then forming a circuit using a specific photosensitive etching resist layer as a mask, and incorporating the mask as it is into a multilayer board without peeling it off. This discovery has led to the completion of the present invention.

That is, the method for manufacturing a multilayer printed wiring board of the present invention includes:
Using a double-sided copper-clad laminate as a cathode, electrolysis is performed in an aqueous solution containing diethylenetriaminepentaacetic acid and/or ethylenediaminetetraacetic acid and copper ions to form a fine copper layer surface on the body surface, and then epoxy groups and photosensitive groups are formed. After forming an inner layer circuit by selectively providing a photosensitive etching resist layer made of a polymer having It is characterized by being integrally formed in a laminated manner.

Further, the inner layer board for multilayer printed wiring of the present invention includes a substrate,
An inner layer circuit provided on the substrate and having a fine to m copper surface formed by immersing it in an aqueous solution containing diethylenetriaminepentaacid and/or ethylenediaminetetraacetic acid and copper ions and performing cathodic electrolysis; It is characterized by comprising a photosensitive etching resist layer made of a polymer having an epoxy group and a photosensitive group, and covering the fine copper surfaces of the inner layer circuit.

The present invention will be explained in detail below.

The double-sided steel-clad M-layer board used in the present invention consists of a substrate and double-sided copper foil, and is made of an inorganic base material such as glass cloth or glass paper, or an organic base material such as aromatic polyamide fiber, and a resin such as epoxy resin or polyimide resin. It may be obtained by stacking the required number of prepregs impregnated and dried, placing copper foil on both sides of the board, inserting it between stainless steel plates, and forming it under heat and pressure in a molding press. It is not limited to materials, manufacturing methods, presence or absence of inner layer circuits, etc.

In performing surface roughening treatment on this double-sided copper-clad laminate, as a pretreatment, the copper surface is polished and degreased, and then immersed in a dilute sulfuric acid aqueous solution to clean the surface by washing with water. After washing with water, use this as a cathode.
It is immersed in an aqueous solution containing diethylenetriaminepentaacetic acid and/or ethylenediaminetetraacetic acid and copper ions, and electrolyzed to form a fine silver surface. Note that it is preferable to use copper for the anode.

The aqueous solution containing diethylenetriaminepentaacid and/or ethylenediaminetetraacetic acid and copper ions used here is:
For example, pentasodium diethylenetriaminepentaacetate (hereinafter referred to as DTPA・5Na) or tetrasodium ethylenediaminetetraacetate (hereinafter referred to as EDTA-4Na)
~3000/7 + particularly preferably 40~1ooa,
'1, sulfuric acid 1 (pentahydrate) 10-1 as a ion
00q/1, particularly preferably 30 to 50c+/7, and by adding sulfuric acid to pH 2.5 to 13.0,
Particularly preferably, it is adjusted to 3.5 to 7.0.

In addition, DTPA-5Na/copper sulfate (pentahydrate) EDTA
-4Na/sulfuric acid 5 liter (pentahydrate) weight ratio is 0.5~
This bath temperature is preferably in the range of 5.0.
-60°C, particularly preferably 40-50°C.

Current density is 2-10A/dn2, processing time is 1-120
10 to 500 A・SeC/d12 as the amount of electricity in seconds
Particularly preferably, it is 30 to 100 A-sec/di2.

When the amount of electricity is less than 1 OA-sec/dn', the formed rough particles are extremely small (approximately 0.02 to 0.03 μm or less) and it is difficult to obtain sufficient adhesion to the resin. Also, 5
If it exceeds 00 A-sec/dn', the target surface itself will stick, but the new surface particles will become new (approximately 1.5-1.
9μ or more) and is not preferable when forming a fine pattern using a liquid resist or the like.

After electrolytic treatment, the surface refinishing process is completed by washing with water and drying. However, if the material is to be stored for a long time until the next inner layer circuit pattern forming step, it is immersed in an aqueous solution containing benzotriazole and its derivatives to form an organic film. However, it may be provided with rust prevention properties, or it may be subjected to general chromate treatment such as immersion in an aqueous solution of dichromate.

As the photosensitive etching resist used in the present invention, a polymer having an epoxy group and a photosensitive group is suitable.

Examples of the photosensitive group include organic groups having an ethylenic double bond such as an acrylic group and a methacrylic group,
One or more types of these can be used. This photosensitive etching resist is first formed over the entire surface by coating with a roll coater or dipping method, and then exposed and developed to form a pattern as a mask, but it is not limited to these methods.

As the bonding sheet used in the present invention, in addition to semi-cured prepreg prepared by coating and impregnating glass cloth or glass paper with epoxy resin, polyimide resin, etc., plastic films and the like can also be used.

As the outer layer copper foil used in the present invention, any commonly used copper foil for copper-clad laminates can be used, and is not particularly limited.

Next, a method for manufacturing a multilayer printed wiring board will be explained.

The copper surface of the double-sided copper-clad laminate is polished, degreased, and further cleaned by immersion in a dilute sulfuric acid/K solution, and then washed with water. Next, it is immersed in an aqueous solution containing diethylenetriaminepentaacetic acid and/or ethylenediaminetetraacetic acid and copper ions, and electrolyzed using this as a cathode and copper as an anode to form a fine #111 surface on the copper surface. Then, the surface is coated with photosensitive etching resist to form a photosensitive etching resist layer, exposed and developed, and then the copper foil is etched to form an inner layer circuit pattern to form an inner layer board for multilayer printed wiring. obtain.

The inner layer plate still covered with the photosensitive etching resist layer and the bonding sheet are laminated, and the outer steel foil layer is further layered on the outermost layer, and then pressure molded together with a press to produce a multilayer printed wiring board.

(Function) The rough surface formed by the present invention is an electrolytic deposit of copper,
It is a uniform, fine granular to ciliated copper layer surface, which is completely different from the rough copper oxide surface obtained by blackening treatment. Therefore, it has extremely strong hydrochloric acid resistance, and has excellent adhesion and haloing resistance.

In addition, since etching resist has an epoxy group and a photosensitive group, it is possible to easily form a circuit resist pattern by irradiating it with light. The resist epoxy groups react with the curing agent, and the prepreg and resist are cured together. Furthermore, since the film thickness of the etching resist can be made thinner, etching of fine patterns becomes easier. In addition, there is no need to peel off the film after etching as in the case of using a conventional dry film, which shortens the manufacturing process and eliminates the need for special ilJM equipment.

(Example) Next, the present invention will be explained by examples.

Example 1 After polishing the copper surface of a glass-epoxy resin double-sided copper-clad laminate TLC-W-551M (trade name manufactured by Toshiba Chemical Co., Ltd., copper foil thickness 70 μn, PR-4 grade) with a thickness of 0.5 nm, It was immersed in a 3% H2So aqueous solution for 20 seconds at room temperature, and then washed with water for pretreatment.

Next, using this double-sided copper-clad laminate as a cathode, the following composition was prepared: DTPA-5Na 520/1 Copper sulfate (pentahydrate) 45a/1 pH (adjusted with sulfuric acid) 4.0 Bath temperature 48°C Current density 4A/da2 After cathodic electrolysis for 15 seconds, this was washed with water and then dried. Next, the double-sided copper-clad laminate subjected to cathodic electrolysis was immersed in a solution of PROB IMER48 (manufactured by Ciba Geigy, trade name) as a photosensitive etching resist, pulled up, and dried at 80"C for 30 minutes to a thickness of about 9 μl. A photosensitive etching resist layer was formed.

After drying, the inner layer circuit pattern was exposed on the photosensitive etching resist layer, developed with cyclohexane, and then the silver foil was etched with chromium sulfuric acid, washed with water, and dried at 120° C. for 40 minutes to obtain an inner layer plate. Without removing the photosensitive etching resist layer, three sheets of glass-epoxy 1 repreg (glass cloth thickness O, j
8i11), and further layer copper foil TL-18 on the outermost layer.
Superimpose μn (manufactured by Kashisu Metal Foil & Powder Industry Co., Ltd., trade name),
A four-layer printed wiring board was manufactured by molding at 110°C for 60 minutes and a pressure of 40 kQ/cI2.

A cross section of the obtained printed wiring board is conceptually shown in FIG. The inner layer plate has a pattern of inner layer steel foil 12 on both sides of the substrate 11. The surface of the inner layer copper foil 12 has a finely roughened surface formed by electrolysis in an aqueous solution containing diethylenetriaminepentaacetic acid and/or ethylenediaminetetraacetic acid and copper ions. A photosensitive etching resist layer 13 is formed on the inner layer copper foil 12.

Three Gripregs 4 are placed on the top and bottom surfaces of this inner layer plate, respectively.
Further, an outer layer copper foil 5 is laminated and molded as the outermost layer, and in particular, a photosensitive etching resist 413 is formed.
and the hardened layer of the prepreg 4 are integrated.

Example 2 After polishing the copper surface of a glass-polyimide resin double-sided copper-clad laminate TLC-W-583M (trade name manufactured by Toshiba Chemical Co., Ltd., copper foil thickness 70 μl, PR-4 grade) with a thickness of 0.5 nng, The sample was immersed in a 3% H2So aqueous solution at room temperature for 20 seconds, and then washed with water for pretreatment. Next, using this double-sided copper-clad laminate as a cathode, the following composition was prepared: DTPA-5Na 60 Q/1 Copper sulfate (pentahydrate) 40a/1 pH (adjusted with sulfuric acid) 4,
5 Bath temperature: 48°C, current density: 4A/d11', cathodic electrolysis was carried out for 30 seconds, washed with water, and then dried. Next, a photosensitive etching resist was applied, and the double-sided copper-clad laminate was immersed in a PROB IMER48 (mentioned above) solution, pulled up, and dried at 80°C for 30 minutes to form a photosensitive etching resist layer of about 9 μm. . After drying, the inner layer circuit pattern was exposed on the photosensitive etching resist layer, developed with cyclohexane, and then the copper foil was etched with chromium sulfuric acid, washed with water, and dried at 120°C for 40 minutes to obtain the inner layer plate. Ta. Without removing the photosensitive etching resist layer, three sheets of glass-polyimide prepreg (glass cloth thickness 0.18 In) were stacked on top and bottom of the inner layer board, and the outermost layer was coated with copper foil T L -18 μrg (n output). were superimposed and molded at 190° C. for 90 minutes at a pressure of 40 kG/CI2 to produce a four-layer multilayer printed wiring board.

Example 3 Glass-epoxy resin double-sided copper-clad laminate TCL-W-551M (trade name, manufactured by Toshiba Chemical Co., Ltd., with a thickness of 0.5111 mm)
After polishing the copper surface of the copper foil (70 μm thick, PR-4 grade), it was immersed in a 3% H2SO4 aqueous solution at room temperature for 20 seconds, and then washed with water to provide pretreatment. Next, using this double-sided steel-clad laminate as a cathode, the following composition was prepared: EDTA-4Na 60 Q/1 sulfuric acid @ (pentahydrate) 5 (Jg/l pH 4,5 Bath temperature 48°C Current density 4 A/dn '', cathodically electrolyzed for 15 seconds, washed with water, and dried.Next, the double-sided copper-clad laminate subjected to cathodic electrolysis was immersed in PROBIMER 48 (mentioned above) hot solution as a photosensitive etching resist, and pulled up. After that, it was dried at 80° C. for 30 minutes to form a photosensitive etching resist layer with a thickness of about 9 μm.
After exposing the inner layer circuit pattern to the photosensitive etching resist layer, it was developed with cyclohexane, and then the copper foil was etched with chromium sulfuric acid, washed with water, and dried at 120° C. for 40 minutes to obtain an inner layer plate. Without removing the photosensitive etching resist layer, three sheets of glass-epoxy prepreg (glass cloth thickness 0°18μ) were stacked on top and bottom of the inner layer board, and the outermost layer was coated with copper foil TL-18μm (manufactured by Kuzutsu Kinzoku Co., Ltd., (product name) and heated at 170℃ for 60 minutes at a pressure of 40℃.
Manufacture a 4-layer printed wiring board by molding at kg/c12.

Comparative Example 1 After polishing the copper surface of the glass-epoxy resin double-sided copper-clad laminate TLC-W-551M (described above) with a thickness of 0.5 nl, a dry film was laminated, and the inner layer circuit pattern was exposed and developed. Next, after etching the copper foil with chromium sulfuric acid, the dry film was peeled off. After that, 5
After washing for 30 seconds in %H2So and water, 50 g of Na Cl 02 was added in the following bath composition:
INa OH12g/I Na3P O4・12H2010Q/I bath temperature
Blackening treatment was performed by immersing at 95°C for 3 minutes. The blackened inner layer board was dried at 120°C for 40 minutes, and three sheets of glass-epoxy prepreg (glass cloth thickness 0.18μl) were layered on the top and bottom surfaces, and copper foil TL-18μ11 (front) was layered on the outermost layer. A four-layer multilayer printed wiring board was manufactured by stacking the two layers and molding them at 170'C and a pressure of 40 kg/cn2 for 60 minutes.

Comparative example 2 Thickness 0. ! After polishing the copper surface of OAN's glass-polyimide resin double-sided copper-clad laminate TLC-W-583M (above), a dry film was laminated, the inner layer circuit pattern was exposed and developed, and then the copper foil was coated with chromium sulfuric acid. After etching, the dry film was peeled off. After that, after washing with 5% H2So for 30 seconds and washing with water, the following bath composition was used:
Blackening treatment was performed by immersing at 95°C for 3 minutes. The blackened inner layer board was dried at 120°C for 40 minutes, and three sheets of glass-polyimide prepreg (glass cloth thickness 0.1
811n) and further layer copper foil TL-1 on the outermost layer.
Overlay 8 μl'I (described above) and heat at 190°C.

A four-layer multilayer printed wiring board was manufactured by molding for 90 minutes at a pressure of 40 kg/cn'.

The four-layer printed wiring boards manufactured in Examples 1 and 2 and Comparative Examples 1 and 2 were tested for haloing resistance, heat resistance, and peel strength. Haloing resistance was determined by processing a 4-layer printed wiring board under the following drilling conditions, immersing the board in 4N-HCI (23°C) for a specified period of time, and observing the resulting haloing under a 50x microscope. did.

Drill processing conditions Drill diameter 0.3in Drill rotation speed 72.000 rl) 1 Feed rate
The results of these tests are shown in Table 1. The multilayer printed wiring board of the present invention has excellent haloing resistance, heat resistance, and adhesion, and there is no problem in practical use. Also, there was no loss of the roughened surface of the copper, and the productivity was high.

Table (unit) *1: ○ means no haloing, X means haloing of 200 μ or more occurs Book 2: ○ means no abnormality, Δ means measling occurs [Effects of the invention] It is clear from the above explanation and Table 1 As described above, the production of the multilayer printed wiring board according to the present invention is very excellent. Namely: (1) Since the fine rough side surface of the present invention is soaked in acid resistance, no haloing that causes deterioration of adhesion or peeling between the eyebrows occurs.

■ Excellent heat resistance and sufficient adhesion.

■ Since it is protected with a photosensitive etching resist, there is no loss of copper on the roughened surface, there is no accompanying drop in heat resistance, and the yield is improved.

■ The process of removing the etching resist can be omitted;
Processes can be simplified and productivity improved.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a multilayer printed wiring board according to the present invention. DESCRIPTION OF SYMBOLS 1... Inner layer board, 11... Substrate, 12... Inner layer copper foil, 13... Photosensitive etching resist layer, 4.
...Prepreg, 5...Outer layer #l foil. Figure 1

Claims (1)

[Claims] 1. Using a double-sided copper-clad laminate as a cathode, electrolysis is performed in an aqueous solution containing diethylenetriaminepentaacetic acid and/or ethylenediaminetetraacetic acid and copper ions to form a fine copper rough surface on the copper surface, Next, a photosensitive etching resist layer made of a polymer having an epoxy group and a photosensitive group is selectively provided to form an inner layer circuit, and then bonding is performed with the inner layer board on which the inner layer circuit has been formed without removing the resist layer. A method for manufacturing a multilayer printed wiring board, comprising integrally forming a sheet and an outer copper foil layer. 2. A substrate, and an inner layer circuit provided on the substrate and having a fine copper rough surface formed by immersing it in an aqueous solution containing diethylenetriaminepentaacetic acid and/or ethylenediaminetetraacetic acid and copper ions and performing cathodic electrolysis. An inner layer board for multilayer printed wiring, comprising a polymer having an epoxy group and a photosensitive group, and a photosensitive etching resist layer covering the fine copper rough surface of the inner layer circuit.