JPS6055691A - Conductive pattern forming unit of circuit board - 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 The present invention relates to a method for forming a conductive pattern on a circuit board, and its purpose is to provide a circuit board having a conductive part and an insulating part on the same plane and a smooth mirror-like surface. There is a particular thing.

Conventionally, many proposals have been made regarding methods of forming conductive patterns on circuit boards. For example, as shown in FIG. 1(a), an organic adhesive 2 is applied onto an electrically insulating substrate 3 made of paper-phenol resin or glass fiber-epoxy resin, and a metal i1 such as copper is applied. Glue or
Alternatively, as shown in FIG. 1(b), glass rjAH-
There is a method of hot-pressing forming a metal foil 1 of copper or the like onto an electrically insulating substrate 3 made of diallyl phthalate resin prepreg, and curing the prepreg and adhering the metal foil at the same time. After manufacturing the metal foil, there is a method of removing unnecessary parts of the metal foil by etching or the like. Also,
On the other hand, there is also a method in which, instead of removing unnecessary parts of the metal foil, a metal such as copper is deposited by plating only on the necessary parts to form a conductive pattern.

However, as shown in FIG. 2, the circuit boards obtained by these methods all have a conductive pattern 4 protruding from an electrically insulating substrate 3, and the conductive portion and the insulating portion are the same. It is impossible to do 1- as shown in G.

In order to reduce the size to about 11L, a conductive pattern is formed on a release plate by a printing method, and then it is inverted and pasted onto an electrically insulating plate 1, and various other methods are used. The draft is ii [but can be used in the printing law) #city (II +A ll
There is a limit to the resistance value, and it is extremely difficult to build a circuit with low resistance (3L), and from the viewpoint of printed films II and I,
In general, to flow a current, it takes 14 ((There is no immediate difference,
1) It was difficult to create 10 fine patterns.

Book phone! II f'+ etc. consider the point 181 [,
In order to obtain a circuit board that takes advantage of the excellent features of the number of copper-clad laminated layers and has a conductive part and an absolutely H part h < li ■ 1- on the back side, and a smooth mirror-like surface, 81 tests were carried out. , Completed a new conductive pattern formation method [1], and succeeded in manufacturing a circuit board with wide-area applications.

Leenawa 15, Akira Kitsuo, is a process of removing unnecessary parts of a copper layer electrodeposited on an aluminum base material to form a conductive pattern, and depositing the conductive pattern on an electrically insulating substrate so that the pattern surface is A conductive part and an insulating part, characterized in that the conductive part and the insulating part are laminated so as to be in contact with an insulating substrate and a laminate is obtained by thermoforming, and the process of dissolving and removing the aluminum base material in the laminate by an alkali treatment. This is a method for forming conductive patterns on circuit boards that are on the same plane.

The present invention will be explained below with reference to the drawings. Figure 3<a)~
FIG. 4 shows one embodiment of the invention. FIG. 3(a) shows a copper layer 6 electrodeposited on an aluminum base material 5 (hereinafter referred to as aluminum-coated copper foil). Since copper and aluminum are strongly bonded and the copper layer is formed by electrodeposition, the interface has good smoothness.

The surface of the copper layer 6 may be subjected to an appropriate treatment in order to increase the adhesive strength with the electrically insulating substrate. Figure 3(b) shows
On the aluminum base material 5 by various well-known methods,
A conductive pattern 4 is formed by removing an unnecessary part 3 of the copper layer with a tweezing solution that does not attack aluminum. Figure 3 (C
) is an electrically insulating thermosetting 111 resin J:/ζ1,1.
14 electrically insulating plates made of thermoplastic resin;
)) The conductive patterns 4 formed on the aluminum base material 5 are shown laminated and hot-pressed.
(It is embedded in an electrically insulating substrate. The aluminum base material 5 in FIG. 3 (0) is removed from an alkali.) The conductive pattern 4 is removed with a Norminum cutting solution as shown in FIG. ．． is embedded in the board 3, the conductive part and the insulating part lie on the same plane (li'+l), and the circuit board has a smooth mirror-like surface.

Furthermore, according to the present invention, a mere conductive path using a copper layer is used instead of G and L, and as shown in FIG. After assembling the resistor element 7 by printing or other methods, it is laminated with an electrically insulating substrate as described above, hot-press molded, and the aluminum base material is removed, as shown in Fig. 6. In this way, it is possible to manufacture a circuit board in which a conductive part, an element part such as a resistor, and an insulating part are all on the same plane.

The thickness of the aluminum base material of the aluminum-coated i-foil may be selected in consideration of ease of handling and removal of aluminum after forming the conductive pattern, but a thickness of about 30 to 100 μm is most convenient for use in the present invention. The thickness of the copper layer depends on the intended use of the circuit board. 3 between the pins of a 2.54 W IC
In order to form a fine pattern that allows the lines of a book to pass through,
For example, while using a thinner copper layer, such as 5μ, has advantages such as less undercut due to etching, a thicker copper layer is advantageous for purposes such as passing large currents.

Various known methods can be applied to form a conductive pattern on aluminum-coated copper foil. ! For example, in order not to attack the aluminum base material, a solvent-soluble resist agent is uniformly applied on the copper layer, and after provisional core-1, ultraviolet rays are irradiated through a pattern mask to remove the weak The resist agent is removed during the development process. Then, after dipping in an etching solution consisting of, for example, persulfate antamine 11 solution 817 to dissolve the copper layer in the non-nozzle portion, the resist agent is removed by 1 liter.
Form an Il[)-C1 conductive pattern.

In order to embed the conductive pattern obtained above, it is advantageous to use thermosetting 111 resin or thermoplastic resin of electrical insulation 11I. As these resins, all of the alkali-resistant resins listed in item (1), which have been conventionally used as insulating materials for rigid and flexible printed wiring boards and circuit supports, can be used. When used as a laminate, fluorocarbon resin-paper, epoxy resin-glass film 1
] Su, Epoxy resin-Paper, L-Bo 1-C Resin-Glass paper, ■Poxy resin-Synthetic fiber 1I11 Ri, Unsaturated polyester-Glass mat, Unsaturated polyester-Synthetic!l fiber non-woven fabric, diallyl phthalate Resin-glass cloth, diallyl isophthalate resin-glass cloth.

Examples include diallyl terephthalate resin - Ten Thousand Las Cross. The resin content in the laminate is suitably in the range of 40 to 70 parts by weight. In addition, when a terephthalic acid diallyl ester copolymer resin newly developed by the applicant is used as the resin for the electrically insulating substrate, the resin itself has electrical properties, heat resistance,
It is advantageous because it has excellent properties such as high temperature and humidity resistance, bending strength, and impact resistance.

The above-mentioned terephthalic acid diallyl ester copolymer resin refers to a copolymer obtained by polymerizing terephthalic acid diallyl ester and an aromatic hydrocarbon in the presence of an organic peroxide and an azo compound. A terephthalic acid diallyl ester copolymer as described in 1 is preferable as the resin used for the electrically insulating substrate. That is, the following formula (I) 7- However, in the above formula (I), R1 and R2 are respectively a hydrogen atom and a lower alkyl group J: I represents a group selected from the following group, and 1-1 to 3. is an integer.

A copolymer resin of an aromatic hydrocarbon having at least one hydrogen atom at the benzyl position represented by the following formula (II) and a terephthalic acid diallyl ester represented by the following formula (II), wherein (a) 8 formula (I) It has a structure in which a monomer unit of formula (I) and a carbon-carbon bond are formed at the end of the 1li position of the heptadmer. Furthermore, (b), the carbon-carbon bond formed by the allyl group of the formula (I) monomer unit of the copolymer resin; is a copolymer resin having a structural feature of 3 to 10 pieces. Furthermore, copolymer resins having the following properties are desirable.

(C) Iodine value 40~ by Rice (Wijs) method measurement
85° (d) True specific gravity at 30°C is 1.20 to 1.25° (
e) Softening range: about 50 to about 120°C.

(r)so wt% methyl ethyl ketone solution viscosity 80~3
00cps (30℃).

(0) Polystyrene equivalent number average molecular weight (llln > 4000 ~ 4000) measured by GPC (gel permeation chromatography) method
10,000, weight average molecular weight (FIW) is 70,000
~200000, ratio of 1 pn to 8w FIW /R
The molecular weight distribution expressed in n is 10 to 40 degrees (h).Measured using a Brabender plastograph.
I? Twisting time is 5-6!1 minutes.

Nailj, 1. fi+:Details of the manufacturing method of the anti-dialyl ester copolymer resin are described in Japanese Patent Application No. flit Fi 7 180981 filed earlier by the present applicant.

In the present invention, 1- terephthalic acid diallyl ester J-prepared resin is applied to paper, glass cloth, glass pine 1,
Glass non-woven fabric, synthetic IIN cloth, synthetic fiber eaves 1 non-woven fabric 1
In combination with No. 1, it can be used as an electrically insulating substrate with impact resistance superior to the other 111 materials. (c) Of course, the polymer resin may be used after being modified with other trees 1111, such as Tadoepo diallyl phthalate resin or unsaturated polynispur tree 1114. In addition, polybismaleimide, 13''l' resin, triazine resin, resin M/]-V:1-C resin, etc. can be used similarly.

. 1-Flexible circuit board is required for B+.
Case number, 1, polyester, vinyl chloride resin, epoxy resin, glass laminate, fluorine-based copolymer, polysulfone, terephthalic acid diallyl ester copolymer resin-glass fiber or synthetic mH laminate, etc. plastic sheet 1
- Alternatively, a film can be used. Alternatively, it is also possible to use not only a laminate but also a molding material to form an electrically insulating substrate.

If the patterned surface of the conductive pattern formed on the aluminum-coated copper foil and the material selected from the various electrical insulating substrates mentioned above are laminated so that they are in contact with each other, and then hot-press molded, an aluminum product as shown in Figure 3 (C) can be obtained. A circuit board with a base material is obtained. The molding conditions may be selected appropriately depending on the resin used for the electrically insulating substrate, but usually the temperature is 100 to 190°C and the pressure is 5 to 100°C.
It is in the range of 1000 yen/d.

To remove the aluminum base material, alkaline solution,
For example, etching may be performed using an etching solution such as sodium hydroxide 5 (1 (1/!), sodium gluconate 1 g/β, etc. After removing the aluminum layer, washing with water,
0% persulfur 11- If the surface dirt is removed by soaking the steel in a weak steel weighting agent such as ammonium acid, it will look like 1 shown in Figure 4 or Figure 6.
A 1j1-way U plate can be obtained. What is circuit surface protection? In order to maintain the adhesion properties, electrical patterns may be plated with gold, tin/nickel, tin/lead, tin, etc.

By utilizing the present invention for right-hand movement, in addition to circuit boards with conductive patterns on one side and both sides, multi-layer blanks can be manufactured.
l! It is also possible to do so.

According to the method of the present invention, the aluminum-coated copper foil can be sprayed in advance! Cloth, JJI! Since each process such as imaging and etching can be performed, electrically insulating substrates containing various organic substances can be treated with etching solutions and other chemicals, moisture, etc.
It has the advantage of being less exposed to heat, etc. and less susceptible to damage, and one of its important features is that it is a highly accurate circuit board with excellent single-method stability.

The circuit board prepared in this way has a conductive part and an insulating part on the same plane, and has a smooth mirror-like surface, so it is suitable for applications such as sliding on the circuit board. It is especially suitable for It would be even more beneficial if an anti-wear agent or the like was added to the electrically insulating substrate to improve its wear resistance.

The circuit board obtained by the method of the present invention can of course be used as an excellent high-performance printed wiring board, but other examples include multi-polar connectors, resistors, etc. There are many fields where the sliding properties of the smooth surface can be utilized, such as by incorporating the small motor Funmiko Cheetah and carbon electrodes into various composite elements, potentiometers, encoders, sensors, etc., to create power supply circuits.

As explained above, the features of the present invention are sufficiently clear including the embodiments, but an example is shown in which a thermosetting resin containing the above terephthalic acid diallyl ester copolymer resin is used as an electrically insulating substrate, and furthermore, fir I, < i, IJ clear. However, it is clear from the above description that the present invention is not limited to this.

Production of terephthalic acid diallyl ester copolymer resin Turbine type variable stirrer, double pipe type supply nozzle for monomer and catalyst supply, nitrogen purge [1, leak valve, limp ring port, temperature gauge and pressure dew 1] ¥160 out of what I prepared
n+, internal volume 1201 di-17 (4' S IJ
Using a polymerization tank made of S 304 1. The double pipe supply nozzle for supplying dinomer and catalyst is installed below the liquid level in the body of the polymerization layer, and the inner diameter of the outer pipe is 1.5n from the moe entering the polymerization tank.
The opening time during hit distillation in the supply piping was made as short as possible. Three such nozzles were installed in preparation for nozzle blockage. A 1j sampler was also installed in the body of the polymerization tank, so that samples of the liquid phase could be collected using the internal pressure during the reaction. An oil rotary vacuum pump and a nitrogen cylinder were connected to the nitrogen persilo, allowing them to be switched as needed.

In the above polymerization layer, xylene 60I was added as shown in Table 1 below.
C11 was charged, the pressure was reduced with a vacuum pump at room temperature, and the pressure was returned to normal pressure with nitrogen gas. After the air in the tank was replaced with nitrogen by repeating the operation three times, the pressure was reduced again and the polymerization tank was sealed. Start the stirrer and stir at 240PPM,
Steam was passed through the jacket and the temperature was raised to 140°C.

The stirring speed was increased to 720 PPM, and terephthalic acid diallyl ester was added from the outer tube of the double tube nozzle at a predetermined rate, and di-tert-butyl peroxide (DTBP) was added at the same time.
O) and xylene were mixed in advance at a molar ratio of 0.5:1, and the mixture was discharged at a predetermined speed at a discharge pressure of 70 kg/a.
I? was supplied to the polymerization tank using a pump. During this time, the steam was adjusted so that the temperature of the polymerization tank was maintained at 140°C. Furthermore, the formula (I) terephthalic acid diallyl ester (DA
T) was cooled to 15°C, and the mixture of di-tert-butyl peroxide and xylene was cooled to 515°C, and the piping leading to the polymerization tank was kept cool. The combined tank pressure is 0.3~2-/cjQ.

When the supply of terephthalic acid diallyl ester, xylene, and di-tert-butyl peroxide has been completed at the specified temperature, stop the steam, reduce the stirring speed, and cool the mixture by passing cooling water through the 24OR+-) M and 1 housing jackets. M L 1ko. Room temperature 1
After cooling to a temperature close to 1711 LJ, the leak valve was returned to normal pressure to block the polymerization reaction.
1. Track the reaction using refractive index and GPC.

The feed rates and usage of cyfuryl]-ster, xylene, and di-t e +' t-butyl peroxide are shown in Table 1 below.

The volatile content of the polymerization reaction solution obtained in Step 1 and 1 is distilled off using a thin film evaporator, and the amount of unreacted xylene in the evaporation residue is calculated based on the total of the copolymer resin and unreacted diallyl terephthalate. The ratio 16- was set to 0.3:1 by weight, and then the evaporated residue was dropped into a stirring tank containing methanol in an amount 5 times the weight of the supplied diallyl terephthalate while stirring, and the copolymer resin was stirred. It was precipitated. The precipitated copolymer resin was thoroughly washed with the same amount of methanol, filtered, dried, and pulverized to obtain a powdered copolymer resin.

Table 1 shows the yield and physical properties of the copolymer resin.

Table 1 In Table 1 above, (1) is the measured value of polystyrene exchanged camphor by gel permeation chromatography method 7.
A 50CGPC,I apparatus was used.

For (2), a light transmission automatic melting point measuring device manufactured by Metsy Co., Ltd. 1PF61J was used.

(3) is a value measured using a Brabender Plastograph manufactured by Brabender (Germany).

Mixing chamber volume 50cc, rotor type W 50 +-1, sample 50g + zinc stearate 0.5g, kneading chamber temperature 1
Kneading resistance is 5000 at 30℃ and rotor rotation speed 22PPM.
Continue until +a-g is reached, and from the torque curve of the recording paper,
The lowest torque value was defined as the Brabender melt viscosity, and the time from the end of sample loading to 5000 mg was defined as the processing time.

Example: Conductive pattern formation on aluminum-coated copper foil〉Mitsui Metal Mining Co., Ltd.
Co., Ltd. rUTc foil 40E 9J19- was uniformly coated with 1'l of solvent, and after drying, ultraviolet rays were irradiated through a pattern mask.
The unnecessary Nozist agent was removed with a solvent. Next, the copper layer in the non-resist area was dissolved by immersing it in an etching solution consisting of ammonium persulfate solution, and then the nosist agent was removed.

<Preparation of 4 sheets of electrical insulation L> Diallyl terephthalic acid ester produced above was mixed and impregnated with 80 infi parts of L polymer resin, 20 parts of unsaturated polyester, 2 parts by weight of dicumyl peroxide, and 100 parts of methyl ethyl ketone. A varnish was made and a plain weave glass cloth treated with methacrylic silane (202 o/t)
), dried at room temperature and further dried at 80°C for 30 minutes to form a prepreg of 1! It was. The resin content in the prepreg is 4! i,! i% by weight. Here, the unsaturated polynisdel used was anhydrous phthalate @ 0.5 mol, anhydrous 7
1121% 11005 mol and propylene glycine 1-
Acid value 28.0 obtained by dehydration condensation of 1 mole of
It is a polyester with a softening temperature of 80°C.

20- Molding of circuit board> The patterned surface of the conductive pattern on the aluminum-coated copper foil was laminated so that it was in contact with the electrically insulating substrate prepreg. Six prepregs were used. Heat plate temperature 165℃, pressure 5
Molding was carried out for 30 minutes at 0 kq/cot to obtain a laminate.

<Removal of aluminum base material> The above laminate was immersed in an etching solution consisting of 50 (1/(11) sodium gluconate 1 g/! at a temperature of 10°C to remove the aluminum layer, and after thorough washing with water,
Clean by soaking in 0% ammonium persulfate solution for 10 seconds,
I got a circuit board. The obtained circuit board had a conductive part and an insulating part on the same plane, and had a smooth mirror-like surface.

[Brief explanation of the drawing]

Figures 1(a) and 1(b) are cross-sectional views of a conventional metal foil-clad laminate, Figure 2 is a cross-sectional view of a conventional circuit board, and Figure 3 (
Figures 3(a) to 3(0) and 4 show one embodiment of the present invention. Figures 3(a) to 3(C) are sectional views of each process, and Figure 4 is a tri-section diagram. A sectional view of the U plate, FIGS. 5 and 6 show other embodiments of the present invention, FIG. 5 is a sectional view of the process, and FIG. 6 is a sectional view of the circuit board. 1: Metal foil 2: Adhesive 3: Electrical insulating base 1k 4: Conductive pattern 5 Nialuminum base material 6: Copper layer 7: Low resistance Applicant Osaka Soda Co., Ltd. Agent Patent attorney Toru Mayo 23- 3 T'! l (1:l) Koi 3 11 (t
) Ne 41 Power Note Da 7m Name Otsu 1ko

Claims (1)

[Claims] Step of forming a conductive pattern by removing unnecessary portions of the copper layer electrodeposited on the aluminum substrate, laminating the conductive pattern on an electrically insulating substrate so that the pattern surface is in contact with the insulating substrate, and forming the conductive pattern under hot pressure. Formation of a conductive pattern on a circuit board in which conductive parts and insulating parts are on the same plane, characterized by the following steps: a step of preparing a laminate by dissolving and removing the aluminum base material in the laminate by an alkali treatment. Law.