JPH07312481A - Manufacture of metal-coated glass epoxy resin board - Google Patents

Abstract

PURPOSE:To provide a method of manufacturing a glass epoxy resin board, which is necessary for forming a very microscopic circuit with good accuracy in the case where the board is used as an electronic component material, such as a printed-wiring board, and is formed with a metal-coated layer which is very thin and has a fully high-reliability adhesion. CONSTITUTION:In a process of manufacturing a metal-coated glass epoxy resin board of a constitution, wherein a plated film consisting of nickel, cobalt or each metal alloy of their metal alloys is formed on the surface of a glass epoxy resin board by an electroless plating, after the plated film consisting of the nickel, the cobalt or each metal alloy of their metal alloys is formed on the surface of the glass epoxy resin board by the electroless plating or after a copper plated film is further formed on the plated film, a heat treatment is performed on the board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a metal-coated glass epoxy resin substrate suitable as a material for a printed wiring board having a fine circuit.

[0002]

2. Description of the Related Art A copper-clad glass epoxy resin substrate used as a material for a printed wiring board is a so-called glass epoxy resin plate in which glass cloth is impregnated with an epoxy resin, and a copper foil in which an adhesive is previously applied to a bonding surface. Or a method of thermocompression bonding a prepreg and a copper foil to a glass epoxy resin.

Conventionally, the copper foil used as the copper coating layer formed on the surface of this type of copper-clad glass epoxy resin laminate is a so-called electrolytic copper foil, and the thickness thereof is usually about 35 μm and about 18 μm. It was. The circuit on the printed wiring board is obtained by etching a portion of the copper foil on the copper-clad glass epoxy resin substrate other than the circuit portion and dissolving and removing the portion. The side wall portion of the circuit portion that is also melted at the same time causes so-called side etching, and the side wall portion melted by this side etching becomes more remarkable as the thickness of the copper foil to be coated increases, and it also depends on the circuit shape and the circuit formation position. Because it doesn't look like
It was extremely difficult to form a circuit having a good dimensional accuracy and a good shape.

On the other hand, with the recent development of electronic equipment, printed wiring boards have come to be widely used for consumer equipment such as televisions and cameras, industrial equipment such as computers, and the like. High-density wiring has been required. In order to meet such requirements, it is required to manufacture a copper clad laminate using thinner copper foil with high dimensional accuracy, and recently, an extremely thin electrolytic copper foil such as a 9 μm thick foil has been used. Copper clad laminates have come into use.

As described above, the use of the electrolytic copper foil having a thickness of 9 μm has made it possible to obtain a printed wiring board having a circuit with a considerably high density.
Since the electrolytic copper foil of μm has insufficient mechanical strength and is difficult to handle by itself, it is necessary to use the aluminum foil together with the copper foil as a reinforcing carrier. For this reason, the copper-clad glass epoxy resin substrate is used. Since the step of removing the aluminum foil by etching is required to form the circuit pattern on the above, the process becomes complicated and it is economically disadvantageous.

Furthermore, in order to accurately form a fine circuit on a wiring board, the use of the above-mentioned thin electrolytic copper foil is still insufficient, and the thickness of the copper coating layer is further reduced. Is required.

In order to meet such a demand, a method of forming a thin copper coating on the surface of a glass epoxy resin by electroless plating has been studied. Generally, in order to form electroless plating on the surface of resin, it is difficult to form a plating film having sufficient adhesion even if the resin is subjected to plating treatment as it is. Chemically etching the surface to form hydrophilic groups on the resin surface or forming fine irregularities by physical means to improve the adhesion between the resin and the plating film. There is.

[0008]

However, even if the above-mentioned conventional electroless plating treatment is applied to the glass epoxy resin, a sufficient improvement in the adhesion is not recognized, and as a means for further improving the adhesion strength. , N, N-dimethylformamide and the like, it is not only difficult to obtain a plated film with good adhesion even when it is subjected to an etching treatment, and glass such as N, N-dimethylformamide and the like There are many problems such as an organic solvent that is effective in etching an epoxy resin is extremely harmful to the human body.

In order to solve the above-mentioned problems, the inventors of the present invention first formed a plating film of nickel or cobalt or an alloy of these metals on the surface of the glass epoxy resin by electroless plating, thereby improving the adhesion. We have proposed a method for manufacturing glass epoxy resin substrates with excellent metal coating. Then, by adopting the manufacturing method, it becomes possible to realize high-density wiring of the printed wiring board as compared with the case of using the conventional copper clad glass epoxy resin substrate. However, with the recent demand for higher density in electronic device parts, it is required to further reduce the circuit wiring width, and the adhesion between the substrate and the metal coating is obtained by the above-mentioned manufacturing method. There has been a demand for further improvement.

The present invention has been made in order to meet such a demand, and is a metal coating layer having an extremely thin and sufficiently reliable adhesion necessary for forming an extremely fine circuit with high accuracy. It is an object of the present invention to provide a method for producing a glass epoxy resin substrate on which is formed.

[0011]

DISCLOSURE OF THE INVENTION The present inventor has proposed, in the above-mentioned previous proposal by the inventor, plating with a glass epoxy resin substrate and nickel or cobalt or an alloy thereof formed by electroless plating on the surface thereof. Adhesion with the substrate in the case of forming a coating is obtained by a physical bonding force by these plating coatings biting into the recesses in the irregularities on the glass epoxy resin surface and depositing, that is, the anchor effect,
The quality of the adhesion is greatly influenced by the quality of the anchor effect, and the effect of improving the adhesion by the anchor effect is further improved by improving the mechanical strength of the plating film itself by applying heat treatment to the plating film. The inventors have found that they can be increased and have completed the present invention.

That is, according to the present invention, in the process of producing a metal-coated glass epoxy resin substrate in which a plating film of nickel or cobalt or an alloy of these metals is formed on the glass epoxy resin surface by electroless plating, A metal-coated glass, characterized in that the substrate is heat-treated after forming a plating film of nickel, cobalt, or an alloy of the respective metals by electroless plating, or after further forming a copper plating film thereon. It is a manufacturing method of an epoxy resin substrate.

In the present invention, the thickness of the plating film made of nickel or cobalt or an alloy of each metal formed by electroless plating is preferably 0.01 μm or more, and the temperature at which heat treatment is applied to the substrate is It is preferably in the range of 70 to 300 ° C.

[0014]

[Function] Generally, the adhesion between the resin and the plating film formed on the surface of the resin is physically determined by the chemical bonding force generated between atoms and molecules and the anchor effect due to the geometrical interlocking of the bonding surfaces of both. It is categorized as one that is based on the specific binding force. And, when the inventors first formed a plating film on the glass epoxy resin surface by electroless plating with nickel, cobalt, or an alloy thereof, these metals are recognized as copper. Unlike the growth of columnar crystals, the nucleus generation is prioritized, so that the deposition is sequentially performed from the concave portions in the uneven portion present on the resin surface, so that it is possible to exert a good anchoring effect and to improve the adhesion of the plating film. It turns out that it can be increased. However, although the adhesion is improved by such an anchor effect, peeling of the coating sometimes occurs. According to an experiment conducted by the present inventors for the pursuit of this cause, when the plating coating is forcibly peeled from the glass epoxy resin, peeling does not occur from the interface between the resin surface and the metal plating coating. It was found that the plating film itself is destroyed, that is, the peeling of the film can occur from the plating film layer itself when the adhesion strength of the plating film is high but the mechanical strength of the plating film itself is low. Therefore, it was found that it is necessary to further improve the mechanical strength of the plating film layer itself in order to form a plating film that is completely free from peeling.

The present inventor has conducted research on the above-mentioned problems, and as a result, after forming a plating coating of nickel, cobalt, or an alloy of these metals on the surface of a glass epoxy resin by electroless plating, or on it. We have succeeded in improving the mechanical strength of these plated coatings themselves and improving their adhesion by further subjecting the substrate to an appropriate heat treatment after copper plating.

In the present invention, a known method may be applied to the electroless plating with nickel or cobalt or an alloy of these metals applied to the surface of the glass epoxy resin. In this case, nickel and cobalt are respectively added. The effect is the same whether it is deposited as a simple substance or as an alloy. The thickness of the plating film deposited on the glass epoxy resin is preferably 0.01 μm or more. When the thickness is less than 0.01 μm, a sufficient anchoring effect cannot be obtained and the adhesion cannot be effectively improved. Also, even if this thickness is made too thick, there is a certain limit to the improvement of the anchor effect, and since nickel and cobalt have lower electrical conductivity than copper, a conductor circuit is formed on the substrate by subsequent processing. Since the conductivity will be reduced when this occurs, it is preferable to keep the thickness to the necessary minimum. For example, when the final conductor thickness is 5 μm, it is preferably about 0.5 μm or less.

In the present invention, a conductor is formed by further copper plating on the glass epoxy resin substrate on which the plating film of nickel, cobalt or their alloy is formed. In this case, the copper plating may be performed by electroless plating or electroplating. The copper plating may be carried out by the usual method. The conductor thickness formed on the glass epoxy resin substrate thus obtained is not particularly limited. For example, when the substrate is used as a semi-additive substrate, the thickness is about 1 to 5 μm. Is appropriate. Of course, it goes without saying that a substrate having a conductor thickness of 18 μm to 35 μm can be obtained on the substrate obtained by the present invention similarly to the conventional copper clad glass epoxy resin substrate.

In the present invention, the temperature of the heat treatment applied to the substrate is preferably in the range of 70 to 300 ° C.
When the heat treatment temperature is lower than 70 ° C., the effect of improving the mechanical strength of the plated coating by nickel, cobalt, or an alloy of these metals is poor even if the heat treatment time is extended. On the other hand, the heat treatment temperature is 300
If the temperature exceeds ℃, there is a risk that the epoxy resin will deteriorate and adversely affect the mechanical properties. The heat treatment time varies depending on the heat treatment time, the composition and thickness of the plating film, the surface condition of the epoxy resin, etc., and therefore cannot be unconditionally limited, and it is necessary to determine an appropriate range in advance. And, even when these heat treatments are performed after applying a plating film of nickel, cobalt, or an alloy of these metals to the glass epoxy resin surface by electroless plating, it is performed after further copper plating Even in some cases, the effect is almost unchanged.

[0019]

EXAMPLES Next, examples of the present invention will be described. Example 1 Ra. 0.3 μm, Rma
x. After forming fine irregularities of 1 μm, washing with ethyl alcohol, and washing with water, using “OPC-80 Catalyst M” manufactured by Okuno Seiyaku Co., Ltd., a catalyst application treatment was performed on the exposed epoxy resin surface at 25 ° C. for 5 minutes. After washing with water, use Okuno Seiyaku's "OPC-555 Accelerator" to remove 25
After accelerating treatment for 7 minutes at ℃, it was washed with water.

After the above treatment, electroless plating containing nickel sulfate hexahydrate 0.1 mol / liter, glycine 0.3 mol / liter, and sodium phosphinate monohydrate 0.3 mol / liter. Solution, the pH of the plating solution is set to 7, and electroless plating is performed at 50 ° C. for 1 minute to form a uniform 0.05 μm thick nickel-phosphorus alloy plating film (nickel composition 95 on the surface of the glass epoxy resin). %) Was formed.

Next, the obtained substrate was heat-treated by holding it in a heating furnace set at 150 ° C. for 30 minutes. By the above treatment, the thickness of the glass epoxy resin surface is 0.0
A metal-coated glass epoxy resin substrate having a nickel / phosphorus plating film of 5 μm was obtained.

The adhesion strength of the metal coating on the obtained metal-coated glass epoxy resin substrate was measured according to JIS C-648.
1 ", the value is 1.6 kgf /
cm, and the adhesiveness was sufficiently satisfactory. Example 2 Instead of performing electroless nickel plating on the surface of the glass epoxy resin in Example 1, cobalt chloride hexahydrate 0.
1 mol / liter, trisodium citrate dihydrate 0.
Using an electroless plating solution containing 3 mol / liter and 0.3 mol / liter of sodium phosphinate monohydrate, the pH of the plating solution is set to 9, and electroless plating is performed at 90 ° C. for 1 minute to obtain a glass epoxy. 0.01μ thick on the surface of resin
m cobalt-phosphorus alloy plating film (cobalt composition 93
%) Was formed and the heat treatment for the substrate was performed by holding the substrate in a heating furnace set at 70 ° C. for 3 hours to obtain a metal-coated glass epoxy resin substrate in the same procedure as in Example 1.

The adhesion of the coating on the obtained metal-coated glass epoxy resin substrate was measured according to "JIS C-6481", and the value was 1.4 kgf / cm, and the adhesion was sufficiently satisfactory. there were. Example 3 In Example 1, instead of performing electroless nickel plating on the glass epoxy resin surface, nickel sulfate hexahydrate 0.
Electroless containing 1 mol / l, copper sulfate pentahydrate 0.1 mol / l, trisodium citrate dihydrate 0.3 mol / l, sodium phosphinate monohydrate 0.3 mol / l Use a plating solution and adjust the pH of the plating solution to 9
And electroless plating for 10 minutes at 60 ° C., and a copper / nickel alloy plating film (copper: nickel: phosphorus composition ratio 50:45:
Example 5 except that 5) was formed and the heat treatment for the substrate was carried out by holding it in a heating furnace set at 300 ° C. for 2 minutes.
A metal-coated glass epoxy resin substrate was obtained by the same procedure as described above.

The adhesion strength of the metal coating on the obtained metal-coated glass epoxy resin substrate was measured according to "JIS C-648".
The value was 1.4 kgf /
cm, and the adhesiveness was sufficiently satisfactory. Example 4 On the electroless nickel-phosphorus alloy plating film obtained in Example 1, an electroplating solution further containing 80 g / l and 180 g / l of copper sulfate pentahydrate was used, and phosphorus-containing copper was anodized. Then, while performing air stirring and cathode locker, electrolytic copper plating was performed for 10 minutes at a cathode current density of 3 A / dm ² and a temperature of 23 ° C. to obtain nickel.
A metal-coated glass epoxy substrate having a copper coating of 5 μm formed on the phosphorus coating was obtained.

The adhesion strength of the metal coating on the obtained metal-coated glass epoxy resin substrate was measured according to JIS C-648.
1 ", the value is 1.6 kgf /
cm, and the adhesiveness was sufficiently satisfactory. Comparative Example 1 Metal-coated glass was prepared in the same procedure as in Example 1 except that the heat treatment of the substrate after the electroless nickel plating film formation was carried out by holding it in a heating furnace set at 60 ° C. for 24 hours. An epoxy resin substrate was obtained.

The adhesion strength of the metal coating on the obtained metal-coated glass epoxy resin substrate was measured according to JIS C-648.
1 ”, the value is 1.2 kgf /
Since it is cm, it cannot be said that the adhesive strength is sufficiently reliable at a value of this level. Comparative Example 2 Metal-coated glass was prepared in the same procedure as in Example 1 except that the heat treatment of the substrate after the formation of the electroless nickel plating film was carried out by holding the substrate in a heating furnace set at 310 ° C. for 1 minute. An epoxy resin substrate was obtained.

The adhesion strength of the metal coating on the obtained metal-coated glass epoxy resin substrate was measured according to "JIS C-648".
The value of 1.6 kgf / cm was obtained when measured according to "1", but the epoxy resin was discolored and this substrate cannot be used as a material for electronic parts. Comparative Example 3 An example except that a nickel-phosphorus alloy coating (nickel composition 95%) having a thickness of 0.005 μm was formed on the glass epoxy resin surface by setting the electroless nickel plating time to 45 seconds in Comparative Example 3. A metal-coated glass epoxy resin substrate was obtained by the same procedure as in 1.

The adhesion strength of the metal coating on the obtained metal-coated glass epoxy resin substrate was measured according to "JIS C-648".
1 ”, the value is 1.2 kgf /
cm, and a metal-coated glass epoxy resin substrate having sufficiently reliable adhesion strength could not be obtained.

[0029]

As described above, according to the method of the present invention, a metal-coated glass epoxy having a metal coating on the surface of the glass epoxy resin, which has been extremely difficult in the past and has an extremely thin and sufficiently reliable adhesion, is obtained. Since a substrate can be obtained, an electronic component such as a high-density printed wiring board having a very fine circuit can be advantageously obtained by using this substrate, and the effect is great.

Claims (4)

[Claims] 1. A process for producing a metal-coated glass epoxy resin substrate in which a plating film made of nickel, cobalt, or an alloy of these metals is formed by electroless plating on the surface of the glass epoxy resin. A method for producing a metal-coated glass epoxy resin substrate, which comprises subjecting a substrate to heat treatment after forming a plating film of nickel, cobalt, or an alloy of respective metals by electroless plating. 2. The method for producing a metal-coated glass epoxy resin substrate according to claim 1, wherein a copper plating film is further formed on the plating film formed by the electroless plating. 3. The thickness of the plating film made of nickel, cobalt, or an alloy of these metals formed by electroless plating is 0.01 μm or more.
Alternatively, the method for producing a metal-coated glass epoxy resin substrate according to the above item 2. 4. The method for producing a metal-coated glass epoxy resin substrate according to claim 1, wherein the heat treatment applied to the substrate is performed in a temperature range of 70 to 300 ° C.