JPH029192A - Manufacture of ceramic circuit board with resistor - Google Patents

Abstract

PURPOSE:To make an etching process of a conductor metal layer of a thick film needless for reducing cost by forming the conductor metal layer of the thick film only on the necessary part as a circuit pattern according to a formation pattern of a plate resist layer formed on a thin film metal. CONSTITUTION:A resistor layer 3 is formed on a ceramic substrate 1 and a protective layer 4 is formed on the resistor layer 3. A thin film metal layer 20 is formed allover the surface of the substrate 1 and the exposed part of the resistor layer 3. A plated resist layer corresponding to a prescribed circuit pattern is formed on the metal layer 20 and a conductor metal layer 2 is formed on the metal layer 20 of the part having no plated resist layer by electrolytic plating. After peeling the plated resist layer, the metal layer 20 of the part having no metal layer 2 is removed by etching. Thereby, an etching process of the conductor metal layer of the thick film becomes needless.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of manufacturing a ceramic circuit board with a resistor, and more particularly, to a method of manufacturing a ceramic circuit board on which a resistor is formed along with a conductor circuit for normal wiring. It is something.

[Conventional technology]

Conventionally, a method for manufacturing a ceramic circuit board including a resistor is to print a noble metal paste mainly composed of Ag/Pd etc., which will become a conductor circuit, on a sintered ceramic substrate by screen printing or the like. Onboard the ship was a method in which a conductor circuit and a resistor were simultaneously formed by printing a resistor paste containing a frit containing RuO2 as a main component by screen printing or the like and firing it in an oxidizing atmosphere.

However, in the above method, migration is likely to occur, and the wiring resistance is as high as 10 to 30 mΩ/hole. Therefore,
Recently, the above method has been improved to prevent migration, reduce wiring resistance, and reduce the cost of paste materials. A method of forming a conductive circuit and a resistor at the same time by combining resistor pastes containing frit as components and firing both in a nitrogen atmosphere is becoming popular.

However, even with the above method, since the conductive metal paste is screen printed, it is difficult to form fine wiring of 100 μm or less, and the paste contains glass, which results in poor solder adhesion and the production of defective products. There is a problem in that it is easy to break down during use. In addition, the resistor paste needs to be fired in a nitrogen atmosphere, and the paste material is less complete, so it is fully comparable in performance to conventional air-fired resistor pastes in all aspects. I can't say that I will.

On the other hand, as a method for forming fine wiring circuits, a method has been proposed in which a metallizing method is used to form a conductive metal layer that does not contain glass on the surface of a ceramic substrate, and a circuit is formed using photolithography technology. . However, this method has a limitation in that the resistor paste must be fired in an inert or reducing atmosphere in order to prevent the conductive metal layer from being oxidized at the high temperature at which it is fired.

Further, in the subtractive method, when a photosensitive liquid resist is used, there is also a problem that the reliability of the through-hole portion provided in the double-sided circuit board is poor.

Therefore, after forming a resistor layer by printing and firing an air-firing resistor paste containing RuOz as a main component, a protective layer was formed on the resistor layer, and the surface of the ceramic substrate and the resistor layer were coated. The entire exposed area is simultaneously roughened with strong acid, then subjected to catalyst/activation treatment, followed by chemical plating or chemical plating and electroplating to form a conductive metal layer, and this conductive gold aR is pattern etched to form a conductor. A method of forming a circuit has been proposed, published in Japanese Patent Application Laid-open No. 1859-1983.
It is disclosed in Publication No. 95.

In addition, each of the above-mentioned conventional techniques is
This method is disclosed in Japanese Patent Application Laid-open No. 0885, Japanese Patent Application Laid-open No. 194794/1983, and the like. In addition, the applicant of the present application has disclosed Japanese Patent Application No. 61-35767 and Japanese Patent Application No. 63-62 regarding similar technology.
A patent application has been filed under No. 347.

[Problem to be solved by the invention]

However, in the prior art disclosed in JP-A-61-185995 mentioned above, after forming a thick conductive metal layer necessary for a conductive circuit on the entire surface of the ceramic substrate and the exposed portion of the resistor layer, the pattern is Since unnecessary parts of the conductive metal layer are removed by etching, a cumbersome etching process is required for the thick conductive metal layer.In addition, unnecessary conductive metal other than the circuit part is removed, which eliminates the waste of conductive metal. There is a problem that there are many problems and the cost is high. Furthermore, when through-holes are formed in a ceramic circuit board, a part of the through-hole is etched during the etching process, which tends to cause defects such as disconnection of the through-hole. In order to increase the adhesion between the ceramic substrate and the conductor circuit or between the resistor layer and the conductor circuit, the exposed parts of the ceramic substrate and the resistor layer are roughened with strong acid. There is also the problem that the resistor layer is eroded and the quality performance of the resistor layer is adversely affected. In order to prevent such problems from occurring, the roughening treatment should be suppressed to the extent that it does not affect the quality and performance of the resistor layer, but doing so will reduce the adhesion between the conductor circuit, the ceramic substrate, and the resistor layer. It becomes inferior.

Therefore, an object of the present invention is to eliminate the need for the etching process of a thick conductive metal layer in the above-mentioned prior art, provide high through-hole reliability in double-sided circuit boards, enable fine wiring, and have low wiring resistance. It is an object of the present invention to provide a method for manufacturing a ceramic circuit board with a resistor having a highly accurate and highly reliable resistor layer.

[Means to solve the problem]

Among the present inventions that solve the above problems, the invention according to claim 1 includes the following steps (11 to (4)) in the manufacturing process.

(1) A process of forming a resistor layer on a ceramic substrate and forming a protective layer on the resistor layer.

(2) A step of forming a thin metal layer over the entire surface of the ceramic substrate and the exposed portion of the resistor layer.

(3) A step of forming a plating resist layer corresponding to a predetermined circuit pattern on the thin film metal layer, and forming a conductive metal layer by electrolytic plating on the part of the thin film metal layer where there is no plating resist layer.

(4) After peeling off the plating resist layer, a step of etching away the thin film metal layer where there is no conductive metal layer.

According to a second aspect of the invention, when implementing the first aspect of the invention, a ceramic substrate whose surface has been roughened in advance is used.

According to the third aspect of the present invention, in carrying out the first aspect of the present invention, either copper nickel or gold is used as the gold slurry constituting the conductor circuit.

[For production]

According to the first aspect of the invention, a thin metal layer is formed on the entire exposed portion of the substrate surface and the resistor layer, and the metal layer is formed on the thin metal layer according to the formation pattern of the plating resist layer formed on the thin metal layer. Since the thick conductive metal layer is formed by electrolytic plating only in the areas necessary for the circuit pattern, there is no need to remove the thick conductive metal layer by etching as in the prior art.

According to the second aspect of the invention, since the ceramic substrate is roughened in advance, the adhesion to the conductive metal layer formed on the surface is increased.

According to the third aspect of the invention, the conductor circuit is made of copper.

By using nickel and gold, the performance of the conductor circuit can be improved.

(Embodiment) Fig. 1 shows an example of the method for manufacturing a ceramic circuit board with a resistor according to the present invention using a process flowchart, and explanations will be added sequentially according to the process flowchart.
The cross-sectional structure of the manufactured ceramic circuit board with a resistor is shown.

[Process ■]

A sintered ceramic substrate 1 is prepared. The materials of the ceramic substrate 1 are alumina, forsterite steatite, zirconia, mullite, cordierite zircon,
Oxide-based ceramic materials such as titania are mainly used, but
Any ceramic material can be used, such as carbide or nitride.

[Step (2)] If necessary, the surface of the ceramic substrate 1 is roughened. Through this roughening treatment, the thin metal layer 2 formed in a later process is
0 and the adhesion between the thick film conductive metal layer 2 and the substrate surface (so-called anchor effect) can be improved. If the thin metal layer 20 is formed by a vapor phase method, this roughening treatment may not be performed, but if the thin metal layer 20 is formed by a chemical plating method, this roughening treatment may not be performed. preferable. Methods for roughening treatment include, for example, immersing the ceramic substrate l in a solution such as hot phosphoric acid, molten alkali, or HF, or physically roughening it by polishing, sandblasting, etc.; A roughening treatment method can also be adopted.

[Process ■]

A resistor paste is applied to a predetermined position on the ceramic substrate 1 by means such as screen printing so as to form a predetermined pattern and dried. Thereafter, the resistor paste is fired together with the ceramic substrate 1 to form the resistor layer 3.

The resistor paste is PdO/Pd/Ag or Ru.
A usual material for forming a resistor is used, such as a paste obtained by mixing a resistance component such as an O2 type with a glass containing an oxide such as Si, Ca, or AI, or an organic vehicle. When using a resistor paste, it is preferable to select one that is compatible with the material of the ceramic substrate.
Generally, R u Om type materials are preferred as they have the most stable properties.

The method of drying and firing the resistor paste is carried out in the same manner as the usual method of forming a resistor, and for example, the following conditions are generally used. That is, after drying the resistor paste printed on the ceramic substrate 1 by screen printing or the like at a temperature of 50 to 200°C, the temperature at which the glass frit in the components is melted and bonded, preferably 500 to 200°C.
Firing is performed at a temperature of 600 to 950°C, more preferably 600 to 950°C.

[Process ■]

A protective layer 4 is formed covering a portion of the resistor layer 3. This protective layer 4 is formed to improve the heat resistance, moisture resistance, chemical resistance, etc. of the resistor layer 3, and to reduce drift in resistance value. The protective layer 4 is formed by forming a resistor layer 3 and a thin gold B layer 20 in a subsequent process.
and the part for connecting with the conductive metal layer 2,
The entire resistor layer 3 is covered. As the protective layer 4, normal overcoat glass that is also used in conventional manufacturing methods can be used, but instead of this overcoat glass, photosensitive polyimide, polyimide,
Protection M4 made of an organic or inorganic substance made from epoxy resin, triazine-based materials, etc. that is resistant to acids, etc. used in roughening treatment in the subsequent process.
You can also use

The protective layer 4 can be formed by a conventional method, but the following conditions are generally used, for example. That is, by printing and forming the glass base 1- for overcoat to cover the entire resistor layer 3 except for a part using a screen printing method, and then baking the glass paste at 300 to 800°C. , forming the protective layer 4.

[Process ■]

If necessary, exposed portions of the resistor layer 3 that are not covered with the protective layer 4 are roughened. If the thin film metal layer 20 and the conductor metal layer 2 are formed on the exposed portion of the resistor layer 3 which has been roughened in this way, the connection portion between the resistor layer 3 and the thin film metal layer 20 etc. will be improved due to the so-called anchor effect. Adhesion is improved. As for the roughening treatment method, it is not necessary to use a treatment method having a strong roughening effect such as the hot phosphoric acid described in the roughening treatment of the ceramic substrate 1 described above, and even if it is a relatively weak roughening method, The resistor layer 3 can be roughened. As a specific treatment method, for example, a method using an acid such as phosphoric acid, hydrofluoric acid, chromic acid, or sulfuric acid, or an alkaline solution such as NaOH can be used. By this roughening treatment, the exposed portion of the resistor layer 3 and the protective layer 4 are
Although it is okay for the surface of the ceramic substrate 1 to be roughened to some extent, it is necessary to apply a roughening treatment method that does not adversely affect the protective effect of the resistor layer 3 by the protective layer 4 or the performance of the resistor layer 3. is preferred.

[Process ■]

A thin metal layer 20 is formed on the surface of the ceramic substrate 1 and the entire exposed portion of the resistor layer 3. The thin film metal layer 20 is made of various metal materials that are used as materials for ordinary conductor circuits, and is selected from ordinary thin film forming methods such as chemical plating, vapor deposition, sputtering, and ion blating. formed by any method.

In the case of chemical plating, metal palladium is deposited on the surface of the ceramic substrate 1 to activate the surface using a normal sensitizing-activation method. after that,
The activated ceramic substrate 1 is immersed in a chemical copper plating bath or a chemical nickel plating bath to form a thin metal layer 20 of copper, nickel, or the like.

The thin film metal ri 20 can also be formed using a vapor phase method such as evaporation, sputtering, or ion blasting, or a CVD method. When using the gas phase method, in the first step C
A method of forming gold Ha of r or Ti and forming a metal layer of copper or nickel thereon as a second step,
The ceramic substrate 1 and The adhesion with the thin gold mud layer 20 increases.

[Process ■]

A resist having plating resistance is applied onto the thin film metal layer 20 and dried to form a plating resist layer in a pattern opposite to the circuit pattern of the required conductor circuit. As a method for forming a patterned plating resist layer, a method for forming a resist layer in ordinary circuit formation, such as a screen printing method, a method using a photosensitive liquid resist, or a method using a dry film, can be applied.

According to the formation pattern of the plating resist layer, a thick conductive metal layer 2 is formed by electrolytic plating on the portion of the thin gold a layer 20 that is not covered with the plating resist layer. Since the chemical plating method, vapor phase method, etc. used to form the thin film metal layer 20 described above can only form a thin metal layer of about 1 to several μm, the conductive metal layer 2 must have a sufficient thickness necessary for a conductive circuit. This electrolytic plating method is required to form. Since the electrolytic plating is performed on the conductive thin film metal layer 20, the electrolytic plating is performed well and efficiently.

[Process ■]

Peel and remove the plating resist layer. As a stripping liquid, N
Examples include alkalicarinols such as aOH and Nag CO3, but organic solvents can also be used, and other usual stripping solutions can be used. The stripping method is carried out by immersing the ceramic substrate 1 in a stripping solution or by spraying the stripping solution onto the surface of the ceramic substrate 1.

[Process ■]

Next, by etching, the portions of the thin film metal layer 20 that are not covered with the thick conductor metal layer 2, that is, the portions that are unnecessary as a conductor circuit, are removed. As an etching solution,
Examples include sodium persulfate, cupric chloride solution, and hydrogen peroxide based etching solutions, but other common etching solutions can also be used. In this etching, the metal layer is
It is preferable to remove the thin metal layer 20 to the extent that it can be removed with a thickness of about 3 to 3 μl. At this time, even if the thick conductive metal layer 2, which will become the conductive circuit, is etched at the same time, there will be no problem since the conductive metal layer 2 has a sufficient thickness. Conversely, by this etching, the conductive metal layer 2
Since the oxide on the surface of the etching layer is removed and the circuit is further miniaturized, it is more preferable to perform etching to the extent that this effect can be fully exhibited.

[Process [phase]]

Next, if necessary, the ceramic substrate 1 on which the conductive metal layer 2 is formed is heat-treated in a nitrogen atmosphere. The treatment temperature is preferably 200 to 800°C, more preferably 400 to 700°C.

Although this heat treatment has the effect of improving the adhesion between the thin film metal layer 20 and the conductor metal N2 and the ceramic substrate 1, it may not be performed if unnecessary. Although the processing time is set appropriately, it is performed for about 1 to 100 minutes, for example. The heating atmosphere is a vacuum or a nitrogen atmosphere. In addition, if necessary, 2 to 200 p.
It may contain a trace amount of oxygen on the order of pm.

[Step (2)] If necessary, the resistor layer 3 is trimmed to adjust the resistance to a desired value. The trimming method is the same as that used for ordinary circuit boards with resistors, and examples thereof include abrasive trimming, laser trimming, and the like. Among these, laser trimming, which can perform high-speed processing and has high performance, is the most preferable for implementing the present invention.

Through each of the above steps, a ceramic circuit board with a resistor as shown in Figure 2 is manufactured, and as a conductor circuit,
It has a structure in which a thin gold B layer 20 and a thick conductive metal layer 2 are laminated.

In the above embodiment, by using base metal conductors such as copper and nickel, which have low wiring resistance and are inexpensive, as the metal constituting the conductor circuit consisting of the thin film metal layer 20 and the conductive metal layer 2, the line width and line spacing can be reduced to 30 μm. A conductor circuit with a fine pattern can be formed at low cost. Furthermore, if gold is used, there is no worry of migration and the soldering properties are good.

If an air-fired resistor paste such as RuO□ is used, it is possible to form a resistor layer 3 with a higher lamination density and higher reliability than a nitrogen-fired resistor paste. It is possible to manufacture a ceramic circuit board having an extremely high precision resistor layer 3 whose resistance characteristics are within ±2%.

Next, a specific example in which the method for manufacturing a ceramic circuit board with a resistor according to the present invention is actually applied will be described.

Example 1 A 96% alumina substrate (4
A through hole with a diameter of 200 μm was drilled in this ceramic substrate 1 using a laser. This substrate 1 was immersed in hot phosphoric acid to uniformly roughen the substrate surface and the inner wall surfaces of the through holes.

As a result of roughening, the surface roughness increased to a maximum roughness of 2 to 3 microns. After the roughening treatment, it was thoroughly washed and dried. After drying,
A Rub-based resistor paste was screen printed on the ceramic substrate 1, and after drying, it was fired in air at 850° C. to form the resistor layer 3. After this, of the resistor M3,
A glass paste for overcoat was screen printed so as to cover the entire surface except for a part that would be connected to the conductor circuit, and after drying, the protective layer 4 was formed by baking in air at 600°C. .

Next, the exposed portion of the resistor layer 3 was roughened using a 5% hydrofluoric acid solution, and then thoroughly washed with water and dried. The ceramic substrate 1 is sequentially immersed in a treatment solution for sensitizing and activation, and the entire surface of the ceramic substrate 1 and the exposed portion of the resistor layer 3 are coated.
Nucleation of palladium was carried out. The ceramic substrate 1 was immersed in a commercially available chemical copper plating solution to form a thin metal layer 20 consisting of a copper layer having a thickness of about lμ.

A photosensitive liquid resist having plating resistance is applied onto the thin film metal layer 20 formed on both sides of the ceramic substrate l, and a pattern opposite to the required circuit pattern is plated using photolithography technology. A resist layer was formed. Thereafter, electrolytic copper sulfate plating was performed to form a thick conductive metal layer 2 consisting of a 10 μm thick copper layer.

The plating resist layer was peeled off by immersing the ceramic substrate 1 in a 5% Na0Hi solution. The thin film metal layer 20 and the thick film conductor metal layer 2 exposed on the surface of the ceramic substrate 1 are coated with cupric chloride at 1 to 2 am.
The unnecessary thin film metal layer 20 was removed by quick etching.

As a result, a conductor circuit with a line width and line spacing of 50 μm was obtained, and no defects such as disconnection at the through-hole portion were observed.

Next, 50pp for the manufactured ceramic circuit board.
A heat treatment was performed at 600° C. in a nitrogen atmosphere containing 5 m of oxygen.

In the ceramic circuit board with a resistor manufactured as described above, the thin film metal layer 20 made of a copper layer and the conductor metal layer 2 are firmly adhered to the resistor layer 3, and the thin film metal layer 20 and the conductor metal layer 2 are firmly bonded to the resistor layer 3. The adhesion of layer 2 to the ceramic substrate 1 was 2.0 to 3.0 kg/mm, which was an extremely high value.Also, when the resistance characteristics of the resistor layer 3 with respect to the circuit constant were measured, it was ±2%. After that, by trimming and adjusting the resistor layer 3 with a laser trimmer so that the resistance value of the resistor layer 3 becomes the desired value, a through hole 5 as shown in FIG. 2 is formed. A ceramic double-sided circuit board with a resistor was manufactured.

The double-sided circuit board manufactured in this way has higher through-hole reliability than through-holes made using the conventional paste method, and can form fine circuits without using the etching process of a thick conductive metal layer. Wiring resistance has also been reduced. Furthermore, the resistor layer also had high precision and good reliability.

Example 2 A 92% alumina substrate was used as the sintered ceramic substrate 1, and the surface was roughened to a maximum roughness of about 2 μm by immersing it in hot phosphoric acid, and then thoroughly washed and dried. After drying, a Ru 2 O based resistor paste was screen printed on the ceramic substrate 1, and after drying, it was fired in air at 900° C. to form a resistor layer 3.

Thereafter, a glass paste for overcoat was screen printed so as to cover a predetermined portion of the resistor layer 3, dried, and then fired in air at 600° C. to form a protective layer A. Furthermore, the exposed portion of the resistor layer 3 was roughened using a 10% chromic acid solution, thoroughly washed with water, and dried.

A thin metal layer 20 made of a copper layer having a thickness of 0.8 to 1.2 μm was formed on the surface of the ceramic substrate 1 and the entire exposed portion of the resistor layer 3 by chemical plating. A plating-resistant dry film was laminated on this thin metal layer 20, and a plating resist M having a predetermined pattern was formed using photolithography. Thereafter, a thick conductive metal layer 2 made of a copper layer with a thickness of 13 μm was formed by electrolytic plating on a portion where there was no plating resist layer. The plating resist layer consisting of a dry film was peeled off by a spray method using a 4% KOH solution. The surfaces of the thin film metal layer 20 and the conductive metal layer 2 are coated with 2-
As a result of quick etching of about 3 μl, the line width,
A conductor circuit with a line spacing of 50 μm was formed.

As a result, the obtained ceramic circuit board with a resistor had a highly accurate resistance characteristic with respect to the circuit constant of the resistor layer 3 within ±2%. Thereafter, the resistor layer 3 was trimmed with a laser trimmer to adjust the resistance to a predetermined value, thereby completing the production of the resistor-equipped ceramic circuit board.

Example 3 A 99% alumina substrate is used as the sintered ceramic substrate 1, and the surface of this substrate is coated with hydrofluoric acid to a maximum roughness of 1 to 2.
After roughening to μl, it was thoroughly washed and dried. A Rub-based resistor paste was screen printed on the dried ceramic substrate 1, and after drying, it was exposed to 850°C in air.
C. to form a resistor layer 3. A glass paste for overcoat was screen printed so as to cover a predetermined portion of the resistor layer 3, dried, and then fired in air at 600° C. to form a protective layer 4.

Next, the exposed portion of the resistor layer 3 was roughened using a 10% sulfuric acid solution, thoroughly washed with water and dried, and then a thin gold mud layer 20 made of a copper layer was formed by a sputtering method.

A photosensitive liquid resist having plating resistance was applied onto the thin metal layer 20, and a plating resist layer with a predetermined pattern was formed using photolithography. A thick conductive metal layer 2 having a thickness of 12 μm was formed by electrolytic plating according to the pattern of the plating resist layer. Thereafter, the ceramic substrate 1 was immersed in a 20% NaCO solution to remove the plating resist layer.

The thin film metal layer 20 and the conductive metal layer 2 on the ceramic substrate 1 are subjected to quick etching using ferric chloride to a thickness of about 1.5 to 2.5μ, and the line width and line spacing are 50us.
A conductor circuit was obtained. Thereafter, heat treatment was performed at 600°C in a nitrogen atmosphere containing 70 ppm of oxygen.

As a result, in the obtained ceramic circuit board with a resistor, the thin film metal layer 20 made of the copper layer and the connecting portions between the conductive metal layer 2 and the resistor layer 3 are firmly bonded, and the copper layer and the substrate are tightly bonded. The adhesion strength was 2.0 to 3.0 kg/mm, which is a very high value.Also, when we measured the resistance characteristics of the resistor layer 3 against the circuit constant, it was found to be within ±2% with high accuracy. Thereafter, trimming adjustment was performed using a laser trimmer so that the resistance value of the resistor layer 3 became a desired value.

Example 4 A ceramic circuit board with a resistor was produced in the same process as in Example 1, except that a sintered aluminum nitride substrate (2" x 2" Xo, 635 mm) was used and methylene chloride was used as the plating resist stripping liquid. was manufactured. As a result, the variation in the resistance value of the resistor layer 3 of the obtained ceramic circuit board had the same excellent characteristics as in Example I.

Example 5 - A 99% alumina substrate was used as the sintered ceramic substrate, and the resistor was attached using the same process as in Example 2, except that the resistor paste was directly drawn on the ceramic substrate to form a predetermined shape. A ceramic circuit board was manufactured. As a result, the variation in the resistance value of the resistor layer 3 of the obtained ceramic circuit board had the same excellent characteristics as in Example 2.

〔Effect of the invention〕

According to the invention described in claim 1 of the method for manufacturing a ceramic circuit board with a resistor according to the present invention described above,
After forming a thin metal layer on the surface of the ceramic substrate on which the resistor layer and protective layer are formed and on the entire exposed portion of the resistor layer, a plating resist layer corresponding to a predetermined circuit pattern is formed, and the plating resist layer is A thick conductive metal layer is formed using electrolytic plating according to the pattern.
Unlike conventional manufacturing methods, the troublesome process of etching a thick conductive metal layer is no longer necessary. Thick film conductive metal is formed only where necessary for circuit formation, so there is no waste and material costs are reduced. In this invention, the thin metal layer is also etched according to the circuit pattern, but since the thin metal layer is much thinner than the thick conductive metal layer, the etching process does not require much effort. Therefore, there is very little waste of metal material removed.

In addition, since the thick film of conductive metal is not etched, there is no need to worry that when a through hole is formed, a part of the through hole will be etched, resulting in defects such as disconnection.
Through-hole reliability is high.

Moreover, compared to methods such as manufacturing conductor circuits by firing conductor metal paste, it is possible to form fine circuits and use low-resistance conductor metals, resulting in lower wiring resistance.
Since a high performance material can be used as the resistor layer, it is possible to provide a ceramic circuit board having a resistor layer with high precision and high reliability.

According to the invention described in claim 2, in addition to the above effects described in claim 1, by using a ceramic substrate whose surface has been roughened in advance, it is possible to improve the adhesion between the ceramic substrate and the conductor circuit. can.

According to the invention set forth in claim 3, in addition to the above-mentioned effects set forth in claim 1, by using a base metal such as copper or nickel as the conductor metal forming the circuit pattern, it is possible to reduce material cost and reduce wiring resistance. Furthermore, by using gold, there is no need to worry about migration, and the soldering properties are improved.

[Brief explanation of the drawing]

FIG. 1 is a process flow chart showing an embodiment of the present invention, and FIG. 2 is a sectional view of a manufactured ceramic circuit board with a resistor. ■...Ceramic base Fj, 2...Conductor metal layer 20
...Thin film metal layer 3...Resistor layer 4...Protective layer Figure 1 Agent: Takehiko Matsumoto, patent attorney

Claims (1)

[Scope of Claims] 1. A method for manufacturing a ceramic circuit board in which a resistor is formed together with a conductor circuit on a ceramic substrate, which method includes the following steps (1) to (4). Method of manufacturing ceramic circuit boards. (1) Step of forming a resistor layer on a ceramic substrate and forming a protective layer on the resistor layer. (2) A step of forming a thin metal layer over the entire surface of the ceramic substrate and the exposed portion of the resistor layer. (3) A step of forming a plating resist layer corresponding to a predetermined circuit pattern on the thin film metal layer, and forming a conductive metal layer by electrolytic plating on the part of the thin film metal layer where there is no plating resist layer. (4) After peeling off the plating resist layer, a step of etching away the thin film metal layer where there is no conductive metal layer. 2. The method of manufacturing a ceramic circuit board with a resistor according to claim 1, wherein the ceramic substrate has a roughened surface in advance. 3. The method of manufacturing a ceramic circuit board with a resistor according to claim 1, wherein the metal constituting the conductor circuit is one of copper, nickel, and gold.