JPH09255459A - Copper metallizing of ceramic substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for copper metallizing of a ceramic substrate by which a copper metallized layer firmly kept in close contact with the smooth surface of a ceramic substrate can be formed without requiring a special atmosphere such as a reducing atmosphere and the excellent adhesion strength of the metallized layer is obtained even in the case of a material in which the ceramic substrate contains a large amount of a silica component. SOLUTION: This method for copper metallizing of a ceramic substrate comprises forming a primary coat layer containing respective element of copper, vanadium and aluminum on the surface of a ceramic substrate having >=1.0wt.% silica component content, then heat-treating the formed primary coat layer at 450-1100 deg.C in an oxidizing atmosphere, subsequently dipping the heat-treaded layer in a reducing solution, carrying out the reducing treatment and then performing the copper metallizing. The primary coat layer contains even magnesium element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper metallizing method for a ceramic substrate, which is used in manufacturing electronic parts and the like.

[0002]

2. Description of the Related Art A printed wiring board using a ceramic substrate is required to have a strong adhesion between a ceramic substrate and a metallized layer (conductor layer) formed on the surface of the ceramic substrate and a low sheet resistance. In the case of the metallizing method using a metal paste, in order to increase the adhesion of the conductor layer, glass which is melted at the firing temperature and fused to the ceramic substrate is included in the metal paste. Therefore, compared to pure metal,
There is a drawback that the sheet resistance of the conductor layer is increased due to the inclusion of glass.

On the other hand, a conductor layer obtained by a vapor phase method such as a plating method, a vapor deposition method or a sputtering method does not contain impurities, and therefore has a sheet resistance at the same level as that of pure metal. However, in these methods, since the conductor layer is physically bonded to the substrate, the adhesion force of the conductor layer is generally low.
Therefore, before applying metallization, the ceramic substrate is immersed in a high temperature solution of hydrofluoric acid, phosphoric acid, sodium hydroxide, etc., and the surface of the substrate is roughened by a chemical etching method. Conventionally, a method for improving the adhesion is known.

However, since roughening the surface of the ceramic substrate impairs the high frequency characteristics when it is used as a printed wiring board, a conductor layer firmly adhered to the surface of the ceramic substrate that is as smooth as possible. It is desired to develop a metallizing method for a ceramic substrate that can be formed. As a method of forming a conductor layer having excellent adhesion without roughening the surface, various studies have been conducted on pretreatment of electroless copper plating, formation of an underlayer, and the following proposals have been made. ing.

Japanese Patent Publication No. 63-4336 describes Cu, Z.
A paste containing at least one component of a compound of n, Cd, Pb or Bi is applied to a ceramic substrate, and then,
Cu, Zn, Cd, Pb and Bi are heat-treated at a temperature in the range of 350 to 900 ° C. in a non-oxidizing atmosphere.
Of at least one kind of metal or alloy, and then a substitution treatment of substituting at least one of Pd and Pt on the surface of the metal of the above metal or alloy in a solution containing ions of at least one of Pd and Pt. A method of manufacturing a ceramic electronic component is described in which a nickel, cobalt or copper metal electrode is formed by electroless plating. However, in this case, since heat treatment in a non-oxidizing atmosphere is required, there is a problem in that the manufacturing apparatus and manufacturing process are complicated, and further, by the substitution treatment of substituting at least one of Pd and Pt, It is presumed that the adhesion between the underlayer and the ceramic substrate is impaired,
As seen in the example of Japanese Examined Patent Publication No. 63-4336, the maximum tensile strength is 2.75 kg / 5φ area (0.53
It is about kg / 4 mm ² ) and in recent years, further improvement in adhesion has been demanded.

In Japanese Examined Patent Publication No. 3-69191, electroless copper plating is applied to an alumina substrate, and then 300 to 900.
A method is described in which heat treatment is carried out at 0 ° C. in an oxidizing atmosphere, further treatment is carried out at 200 to 900 ° C. in a reducing atmosphere, then electroless copper plating is carried out, and then electrolytic copper plating is carried out. However, in the case of this method, since the treatment is performed in a reducing atmosphere, the manufacturing apparatus and the manufacturing process are complicated, and the reduction treatment is performed at a high temperature of 200 to 900 ° C., and thus the obtained metal film is obtained. Although it is presumed that the wettability of the surface of No. 3 is low, there was a problem that the adhesion between the underlayer after the reduction treatment and the electroless copper plating film formed thereon was insufficient.

In view of these problems, the present inventors have proposed, in Japanese Patent Application Laid-Open No. 7-254769, a new method for metallizing a ceramic substrate capable of forming a conductor layer firmly adhered to a smooth ceramic substrate surface. are doing. This method forms an underlayer containing vanadium and copper on the surface of a ceramic substrate and then 450 to 6 in an oxidizing atmosphere.
This is a method of heat treatment at 20 ° C., then dipping in a reducing solution for reduction treatment, and then copper metallization. But,
In this method, when the ceramic substrate is made of a material containing a certain amount of silica component (specifically, 1.0% by weight or more), the adhesion of the conductor layer (metallized layer) becomes insufficient. It has been found. Generally, when a ceramic substrate is manufactured by firing a green sheet, the silica component tends to be localized in the outermost layer, so in a ceramic substrate of a material containing a certain amount or more of the silica component,
It is estimated that the phenomenon in which the adhesion is insufficient as described above remarkably occurs.

[0008]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a smooth ceramic substrate surface without requiring a special atmosphere such as a reducing atmosphere. A copper metallization method for a ceramic substrate capable of forming a copper metallization layer that is firmly adhered to
It is an object of the present invention to provide a copper metallizing method for a ceramic substrate, which can obtain excellent adhesion of the metallized layer even if the ceramic substrate is a material containing a large amount of silica component.

[0009]

According to a copper metallizing method for a ceramic substrate of an invention according to claim 1, each element of copper, vanadium and aluminum is provided on the surface of the ceramic substrate having a silica component content of 1.0% by weight or more. It is characterized in that a base layer to be contained is formed, then heat treated at 450 to 1100 ° C. in an oxidizing atmosphere, then immersed in a reducing solution for reduction treatment, and then copper metallization is conducted.

A copper metallizing method for a ceramic substrate according to a second aspect of the present invention is the copper metallizing method according to the first aspect, characterized in that the underlayer also contains a magnesium element.

A copper metallization method for a ceramic substrate according to a third aspect of the present invention is the copper metallization method according to the first or second aspect, wherein the ceramic substrate is 20 to 80% by weight of glass powder containing borosilicate glass. Alumina powder 80
~ 11% by weight of the raw material powder,
It is characterized by being a glass ceramic substrate fired at 00 ° C.

A copper metallizing method for a ceramic substrate according to a fourth aspect of the present invention is the copper metallizing method according to any one of the first to third aspects, in which the method for forming the underlayer is that the surface of the ceramic substrate is first formed. The method is characterized by forming a first underlayer containing an aluminum element and then forming a second underlayer containing a copper element and a vanadium element.

A copper metallizing method for a ceramic substrate according to a fifth aspect of the present invention is characterized in that, in the copper metallizing method according to the fourth aspect, the second underlayer also contains a magnesium element.

A copper metallizing method for a ceramic substrate according to a sixth aspect of the present invention is the copper metallizing method according to any one of the first to fifth aspects, wherein the copper metallizing method is an electroless plating method or an electrolytic plating method. The method is characterized by a method of performing electroless plating after performing electroless plating or a sputtering method.

In the present invention, a base layer containing each element of copper, vanadium and aluminum is formed as a base before copper metallization. The copper element in the underlayer becomes copper oxide in the subsequent heat treatment at 450 to 1100 ° C. in an oxidizing atmosphere, but since it is converted into metallic copper by the reduction treatment of dipping in a reducing solution in the next step, Metals in copper metallization
It becomes the metal joint surface. Further, the vanadium element in the underlayer becomes vanadium oxide by the subsequent heat treatment at 450 to 1100 ° C. in an oxidizing atmosphere, and vanadium oxide has good wettability with the ceramic substrate and diffuses to cause an adhesion improver to the ceramic substrate. Acts as. In addition, the aluminum element in the underlayer is 450 to 1100 in a later oxidizing atmosphere.
The heat treatment at 0 ° C. turns it into aluminum oxide, which has good wettability with the silica component existing in the outermost layer of the ceramic substrate, and acts as an effective adhesion improver for the ceramic substrate containing the silica component. Further, in the present invention, when a magnesium element is also contained in the underlayer, the magnesium element is contained in the later oxidizing atmosphere in an amount of 450 to
It is considered that the heat treatment at 1100 ° C. produces magnesium oxide, and this magnesium oxide strengthens the strength of the underlayer, but it functions to further increase the adhesion strength of the finally obtained copper metallized layer. Further, since the diffusion rate of vanadium oxide, aluminum oxide and magnesium oxide to the side of the ceramic substrate is higher than that of copper oxide, an underlayer containing each element of copper, vanadium and aluminum,
Alternatively, no matter what structure the underlayer containing each element of copper, vanadium, aluminum and magnesium is formed, copper oxide appears on the outermost surface of the underlayer after heat treatment in an oxidizing atmosphere. In addition, the structure of the underlayer, first, after forming a first underlayer containing aluminum element, a second underlayer containing copper element and vanadium element, or containing each element of copper, vanadium and magnesium If the second underlayer is formed, each metal element component can be diffused efficiently, so that a copper metallized layer having higher adhesion strength can be obtained. Incidentally, copper used in forming the underlayer in the present invention,
There is no particular limitation on the raw material for supplying each element of vanadium and aluminum and the raw material for supplying the magnesium element to be used as necessary, and a metal, alloy or compound (including oxide) containing each element is included. Can be used. This is because, after forming the underlayer in the present invention, heat treatment at 450 to 1100 ° C. in an oxidizing atmosphere not only has an effect of generating an oxide, but also the oxide of the metal element of the underlayer and the ceramic substrate. This is because it has an action of generating some reaction product between the ceramic component and the oxide of a metal element different in the underlayer and improving the adhesion strength of the finally obtained copper metallized layer. Then, in the present invention, after the heat treatment, the copper oxide in the underlayer is changed to metallic copper by immersing it in a reducing solution and performing a reduction treatment. Since this reduction treatment is performed using a reducing solution, the obtained metallic copper has a property of being capable of firmly joining to copper formed by the later copper metallization.

[0016]

Embodiments of the present invention will be described below.

As the ceramic substrate used in the present invention, oxide-based ones such as alumina, zirconia and barium titanate, nitride-based ones such as aluminum nitride and silicon nitride, and carbide-based ones such as silicon carbide, Alternatively, glass-based materials can be exemplified. The copper metallizing method of the present invention works particularly effectively when the silica component content of the ceramic substrate is 1.0% by weight or more. As an example of the above-mentioned glass-based ceramic substrate, a raw material powder containing 20 to 80% by weight of glass powder containing borosilicate glass and 80 to 20% by weight of alumina powder is 800
A glass ceramic substrate fired at ˜1100 ° C. can be exemplified.

In the copper metallizing method of the present invention, an underlayer containing each element of copper, vanadium and aluminum is formed on the surface of a ceramic substrate. The method of forming the underlayer is not particularly limited, and it can be formed by, for example, an electroless plating method, a sputtering method, a metal paste method, an organic metal resinate (or a paste thereof) method, or the like. Further, as described above, the underlayer may also contain a magnesium element, and in the case of containing a magnesium element, the adhesion strength of the finally obtained copper metallized layer is higher, which is desirable. The thickness of the underlayer is not particularly limited, but is preferably about 0.05 to 3 μm in order to obtain a copper metallized layer having high adhesion. As a method of forming an underlayer, first a first underlayer containing an aluminum element is formed on the surface of a ceramic substrate, and then a second underlayer containing a copper element and a vanadium element, or copper, vanadium and magnesium. When a second underlayer containing each element is formed,
As described above, since each metal element component can be efficiently diffused, a copper metallized layer having higher adhesion strength can be obtained, which is desirable.

In the present invention, an oxidizing atmosphere is used so that some reaction product is generated between the ceramic component of the ceramic substrate and the oxide of the metal element of the underlayer and between the oxides of the metal elements of different underlayers. At 450 to 1100 ° C. If the temperature is lower than 450 ° C, the formation of such a reaction product is insufficient, and the adhesion strength of the finally obtained copper metallized layer becomes insufficient, and if the temperature exceeds 1100 ° C, an oxide of a metal element (especially oxidation) during heat treatment is used. Since the amount of metal components contributing to the improvement of the adhesiveness of the copper metallized layer cannot be secured due to the remarkable scattering of vanadium), the adhesiveness of the copper metallized layer becomes insufficient.

After the ceramic substrate is heat-treated in an oxidizing atmosphere as described above, the ceramic substrate is dipped in a reducing solution to subject the underlayer to a reduction treatment. By this reduction treatment, the copper oxide present in the underlayer is reduced to metallic copper. Any reducing solution may be used as long as it can reduce copper oxide, and for example, a borohydride solution, a hypophosphite solution, a dimethylamine borane solution, or the like can be used.

In the present invention, the reduction treatment is carried out as described above, and the copper metallized layer is formed on the underlayer having the metallic copper on the surface. Since the reduction treatment of the underlayer is performed using the reducing solution, the adhesion between the underlayer and the copper metallized layer is stronger than that in the case where the reduction treatment is performed at a high temperature using a reducing gas. The method for forming the copper metallized layer is not particularly limited, but the content of impurities such as electroless plating, electrolytic plating, electroless plating followed by electrolytic plating, or sputtering. It is preferable to use a method in which the desired thickness is small and the desired thickness is easily obtained.

When manufacturing a ceramic wiring board, nickel,
A metal layer other than copper such as gold may be formed.

[0023]

The present invention will be described below based on examples and comparative examples.

Examples 1 to 4 and Reference Example 1 As shown in Table 1, various ceramic substrates having different silica component contents were prepared. In Example 1, a 96% alumina substrate having a silica component content of 2.0% by weight was used. In Examples 2 to 4, the mixed powder (raw material powder) having the mixing ratio of the MgO—CaO—Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ based glass powder and the alumina powder as shown in Table 1 was used. Glass-based ceramic substrates (low temperature fired glass ceramic substrates) having different silica component contents obtained by firing at 900 ° C. were used. Also,
In Reference Example 1, a 96% alumina substrate having a silica component content of 0.5% by weight was used.

An underlayer containing each element of copper, vanadium and aluminum was formed on the surface of each ceramic substrate. This underlayer is formed by using a copper powder 39 having an average particle size of 1 μm.
100 parts by weight of vanadium resinate paste (manufactured by NE Chemcat, product number: H95K-3, vanadium content 3.0% by weight) and aluminum resinate paste (manufactured by NE Chemcat, product number: H9
5K-4, aluminum content 1% by weight) and 15 parts by weight of copper-vanadium-aluminum mixed paste,
A ceramic substrate was coated on the entire surface by a screen printing method, and then dried at 125 ° C. for 10 minutes to be formed. Next, 5 is applied to the ceramic substrate on which the underlayer is formed.
Heat treatment was performed in the atmosphere at 80 ° C. for 30 minutes. Then, an aqueous sodium borohydride solution having a pH of 12.5 was heated to about 80 ° C., the ceramic substrate which had been subjected to the above heat treatment was immersed therein, and the copper oxide layer on the surface was reduced to form metallic copper. Then, a copper metallized layer having a total film thickness of about 10 μm was formed on the underlayer of the ceramic substrate after the reduction treatment by the electroless copper plating method.

In the substrate on which the copper metallized layer is formed,
The adhesion between the ceramic substrate and the copper metallized layer was measured by the following method. The results are shown in Table 1, and the adhesive strengths in the obtained Examples 1 to 4 and Reference Example 1 were all excellent values.

(Measurement Method of Adhesion) Measurement is performed by the method shown in FIG. First, the ceramic substrate 1 on which the copper metallized layer is formed is etched to form the 2 mm square adhesive force measurement pad 2. Then, as shown in FIG. 1, a 0.7 mmφ tin-plated copper wire 4 is fixed to the adhesive force measurement pad 2 with the solder 3, and then the tin-plated copper wire 4 is pulled using a tensile tester to obtain a ceramic. The adhesive force between the substrate 1 and the adhesive force measurement pad 2 is measured. In addition, the arrow in FIG. 1 shows the pulling direction of a tensile test.

[0028]

[Table 1]

(Comparative Examples 1 to 4, Reference Example 2) As shown in Table 2, various ceramic substrates having different silica component contents were used. That is, in Comparative Examples 1 to 4, the same ceramic substrate used in Examples 1 to 4 was used, and in Reference Example 2, the same ceramic substrate used in Reference Example 1 was used. did.

An underlayer containing a copper element and a vanadium element was formed on the surface of each ceramic substrate. The base layer of these comparative examples did not contain aluminum element. This underlayer is formed by copper powder 41 having an average particle size of 1 μm.
A copper-vanadium mixed paste prepared by mixing 100 parts by weight of vanadium resinate paste (manufactured by NE Chemcat, product number: H95K-3, vanadium content of 3.0% by weight) with 100 parts by weight of the paste is screened on the entire surface of the ceramic substrate. It was applied by a printing method, and then dried at 125 ° C. for 10 minutes to be formed.

Then, the subsequent steps were performed in the same manner as in Example 1, and a copper metallized layer having a total film thickness of about 10 μm was formed on the base layer of the ceramic substrate by electroless copper plating. The adhesion between the ceramic substrate and the copper metallized layer on the substrate on which the copper metallized layer was formed was measured by the same method as in Example 1. The results are shown in Table 2, and the adhesion in Comparative Examples 1 to 4 in which the underlayer does not contain aluminum element is the same as in Examples 1 to 4 using the same ceramic substrate. It was lower than strength. The adhesive force in Reference Example 2 using a substrate having a silica component content of 0.5% by weight is almost the same as the adhesive force in Reference Example 1, and when the silica component content is extremely low, the base layer It was confirmed that the effect of including aluminum element in Al was not remarkable.

[0032]

[Table 2]

Examples 5 to 8 As shown in Table 3, various ceramic substrates having different silica component contents were used. That is, in Examples 5 to 8, the same ceramic substrates as those used in Examples 1 to 4 were used.

Copper, vanadium,
An underlayer containing aluminum and magnesium was formed. This underlayer is formed using aluminum MOD (Meta
l Organic Decomposition) 5 parts by weight of coating type material (manufactured by Kojundo Chemical Laboratory Co., Ltd., product number AL-03, aluminum oxide concentration 3% by weight), 39 parts by weight of copper powder having an average particle diameter of 1 μm, vanadium resinate paste (N -E-Chem Cat, product number: H95K-3, vanadium content rate 3.0
% By weight) and 100 parts by weight of magnesium resinate paste (manufactured by NE Chemcat, product number: Z95C-3,
A copper-vanadium-magnesium-aluminum mixed paste in which 20 parts by weight of magnesium content (1.3% by weight) was mixed was applied on the entire surface of the substrate by a screen printing method, and then dried at 125 ° C. for 10 minutes to be formed. . Then, heat treatment in the air, reduction treatment and copper metallization are performed in the same manner as in Example 1 to obtain a total film thickness of about 1
A 0 μm copper metallization layer was formed. The adhesion between the ceramic substrate and the copper metallized layer on the substrate on which the copper metallized layer was formed was measured by the same method as in Example 1. The results are shown in Table 3, and the adhesive strength in Examples 5 to 8 in which the underlayer also contains magnesium element is the same as that in the above Examples 1 to 4 using the same ceramic substrate. It was confirmed to be stronger than that.

[0035]

[Table 3]

(Examples 9 to 11) As shown in Table 4, various glass-based ceramic substrates having different silica component contents were used. That is, in Examples 9 to 11, the same ceramic substrates as those used in Examples 2 to 4 were used.

Aluminum resinate paste (manufactured by NE Chemcat,
Part number: H95K-4, aluminum content 1.0% by weight) is applied by screen printing method, then 10 at 125 ° C.
It was dried for a minute to form a first underlayer containing aluminum element. Then, the ceramic substrate on which the first underlayer was formed was subjected to heat treatment in the atmosphere at 860 ° C. for 1 hour. Then, a second underlayer containing a copper element and a vanadium element was formed on the entire surface of the first underlayer of the ceramic substrate. This second underlayer is formed by 41 parts by weight of copper powder having an average particle size of 1 μm and vanadium resinate paste (manufactured by NE Chemcat, product number: H95K-
3, vanadium content of 3.0% by weight) 100 parts by weight of a mixed copper-vanadium paste is applied to the entire surface of the first underlayer by a screen printing method, and then 12
It was formed by drying treatment at 5 ° C. for 10 minutes. In the subsequent steps, heat treatment in the atmosphere, reduction treatment and copper metallization were performed in the same manner as in Example 1 to obtain a total film thickness of about 10 μm.
Of copper metallization layer was formed. The adhesion between the ceramic substrate and the copper metallized layer on the substrate on which the copper metallized layer was formed was measured by the same method as in Example 1. The results are shown in Table 4. Examples 9 to 11 in which after forming the first underlayer containing the aluminum element, the second underlayer containing the copper element and the vanadium element was formed.
It was confirmed that the adhesion force in Example 2 was stronger than the adhesion force in Examples 2 to 4 using the same ceramic substrate.

[0038]

[Table 4]

Examples 12 to 14 As shown in Table 5, various glass-based ceramic substrates having different silica component contents were used. That is, Example 12 to Example 1
In Example 4, the same ceramic substrate as that used in each of Examples 6 to 8 was used.

Aluminum resinate paste (manufactured by NE Chemcat,
Part number: H95K-4, aluminum content 1.0% by weight) is applied by screen printing method, then 10 at 125 ° C.
It was dried for a minute to form a first underlayer containing aluminum element. Then, the ceramic substrate on which the first underlayer was formed was subjected to heat treatment in the atmosphere at 860 ° C. for 1 hour. Then, a second underlayer containing each element of copper, vanadium, and magnesium was formed on the entire surface of the first underlayer of the ceramic substrate. This second underlayer is formed by using 39 parts by weight of copper powder having an average particle size of 1 μm and vanadium resinate paste (manufactured by NE Chemcat, product number: H95K-3, vanadium content 3.0% by weight).
The first is a copper-vanadium-magnesium mixed paste in which 00 parts by weight and 20 parts by weight of magnesium resinate paste (manufactured by NE Chemcat, product number: Z95C-3, magnesium content 1.3% by weight) are mixed. The entire surface of the underlayer is coated by a screen printing method, then 12
It was formed by drying treatment at 5 ° C. for 10 minutes. In the subsequent steps, heat treatment in the atmosphere, reduction treatment and copper metallization were performed in the same manner as in Example 1 to obtain a total film thickness of about 10 μm.
Of copper metallization layer was formed. The adhesion between the ceramic substrate and the copper metallized layer on the substrate on which the copper metallized layer was formed was measured by the same method as in Example 1. The results are shown in Table 5. Examples 12 to Example in which after forming the first underlayer containing the aluminum element, the second underlayer containing each element of copper, vanadium and magnesium was formed. It was confirmed that the adhesive force in Example 14 was stronger than the adhesive force in Examples 6 to 8 using the same ceramic substrate.

[0041]

[Table 5]

(Examples 15 to 17, Comparative Examples 5 and 6) The same ceramic substrate as that used in Example 1 was used except that the heat treatment temperature in the atmosphere was changed as shown in Table 6. A copper metallized layer having a total film thickness of about 10 μm was formed by using the same process as in Example 1. The adhesion between the ceramic substrate and the copper metallized layer on the substrate on which the copper metallized layer was formed was measured by the same method as in Example 1. The results are shown in Table 6 including the results of Example 1. From the results of Table 6, the heat treatment temperature in the atmosphere is 450 to
It was confirmed that when the temperature was within the range of 1100 ° C, good adhesion was obtained.

[0043]

[Table 6]

(Examples 18 to 20) The same ceramic substrate as that used in Example 1 was used, except that the copper metallizing method for the substrate after the reduction treatment was changed as shown in Table 7. A copper metallized layer having a total film thickness of about 10 μm was formed by the same process as in Example 1.
The adhesion between the ceramic substrate and the copper metallized layer on the substrate on which the copper metallized layer was formed was measured by the same method as in Example 1. The results including the results of Example 1 are shown in Table 7.
Shown in The adhesive strengths in Examples 18 to 20 were all good.

[0045]

[Table 7]

[0046]

According to the copper metallizing method for a ceramic substrate according to claims 1 to 6, an underlayer containing each element of copper, vanadium and aluminum is formed, and then 450 to 1100 ° C in an oxidizing atmosphere. Since the heat treatment is performed in accordance with the method for copper metallizing a ceramic substrate according to any one of claims 1 to 6, the ceramic substrate is immersed in a reducing solution for reduction treatment, and then copper metallization is performed. Form a copper metallized layer firmly adhered to a smooth ceramic substrate surface without the need for a special atmosphere such as a reducing atmosphere, even if is a material containing 1.0% by weight or more of silica component It becomes possible to do.

In the copper metallizing method for a ceramic substrate according to a second aspect of the present invention, an underlayer containing each element of copper, vanadium, aluminum and magnesium is formed, and then heat treatment is performed at 450 to 1100 ° C. in an oxidizing atmosphere. In addition to the above effects, according to the copper metallizing method for a ceramic substrate according to claim 2, in addition to the above effects, the method is followed by dipping in a reducing solution for reduction treatment and then copper metallization.
It becomes possible to form a copper metallized layer having a better adhesion of the ceramic substrate.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a method for measuring an adhesion force between a ceramic substrate and a copper metallized layer.

[Explanation of symbols]

 1 Ceramic substrate 2 Adhesive force measurement pad 3 Solder 4 Tin-plated copper wire

Claims (6)

[Claims] 1. A base layer containing each element of copper, vanadium and aluminum is formed on the surface of a ceramic substrate having a silica component content of 1.0% by weight or more, and then 450 to 1100 ° C. in an oxidizing atmosphere. A method for copper metallization of a ceramic substrate, which comprises heat-treating, then immersing in a reducing solution to perform reduction treatment, and then performing copper metallization. 2. The method of copper metallizing a ceramic substrate according to claim 1, wherein the underlayer also contains a magnesium element. 3. The ceramic substrate comprises 20 to 80% by weight of glass powder containing borosilicate glass and 80 to 80% of alumina powder.
The raw material powder containing 20% by weight of 800-110
3. The copper metallizing method for a ceramic substrate according to claim 1 or 2, which is a glass ceramic substrate fired at 0 ° C. 4. A method of forming an underlayer, which comprises first forming a first underlayer containing an aluminum element on a surface of a ceramic substrate and then forming a second underlayer containing a copper element and a vanadium element. The copper metallization method for a ceramic substrate according to any one of claims 1 to 3, wherein 5. The copper metallizing method for a ceramic substrate according to claim 4, wherein the second underlayer also contains magnesium element. 6. The method of copper metallization is an electroless plating method,
The copper metallizing method for a ceramic substrate according to any one of claims 1 to 5, which is an electrolytic plating method, a method of performing electrolytic plating after performing electroless plating, or a sputtering method.