JPH0697711B2 - Method for manufacturing ceramic circuit board - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a ceramic circuit board used in various kinds of OA equipment and the like. The present invention provides a method of efficiently and easily obtaining a reliable ceramic circuit board having good dimensional accuracy.

[Conventional technology]

A so-called ceramic circuit board in which a circuit pattern layer such as a resistor portion, a dielectric portion, and a conductor portion is formed on the surface of the ceramic substrate is widely used as a circuit board having excellent heat resistance. It is generally obtained by a method for manufacturing a ceramic circuit board, which comprises forming a circuit pattern layer on the surface of the substrate by a screen printing method.

[Problems to be solved by the invention]

By the way, in the method for manufacturing a ceramic circuit board in which a circuit pattern layer is formed on the surface of the ceramic board by a screen printing method, a drying step is not repeated every time a resistor part, a dielectric part, a conductor part, etc. are printed. However, it has a drawback that the workability is extremely poor because the number of manufacturing steps increases.

On the other hand, in the method for manufacturing a ceramic circuit board of the present invention, the step of transferring the circuit pattern layer in the transfer sheet to the surface of the ceramic board and the firing step for making the transferred circuit pattern layer ceramic are performed. In order to obtain a ceramic circuit board, by forming the adhesive layer in the transfer sheet with a heat-sensitive adhesive layer made of a cellulosic resin, the circuit pattern layer may be distorted or crimped during the firing step. In addition, there is no problem of adhesion failure between the ceramic circuit board and the surface of the ceramic circuit board, and a highly reliable ceramic circuit board with good dimensional accuracy can be obtained.

[Means for solving problems]

The method for manufacturing a ceramic circuit board of the present invention comprises a transfer substrate sheet, a release agent layer formed of a non-migrating thermosetting resin on one surface of the substrate sheet, and a glass frit on the release agent layer surface. From a circuit pattern layer formed of a printing ink containing a, and a heat-sensitive adhesive layer of a cellulosic resin formed on the entire surface of the release agent layer so as to cover the circuit pattern layer. The transfer sheet is placed on the surface of the ceramic substrate so that the heat-sensitive adhesive layer in the transfer sheet comes into contact with the ceramic substrate, and the transfer sheet is pressed, heated and cooled. The transfer pattern sheet in the transfer sheet is transferred to the surface of the ceramic substrate by peeling off the transfer base material sheet and the release agent layer, and thereafter the circuit pattern layer is formed. Firing the ceramic substrate at a temperature above the softening point of the glass frit contained in the, thereby obtaining a ceramic circuit board having a circuit pattern layers which are ceramics of.

The structure of the transfer sheet used in the method for manufacturing a ceramic circuit board of the present invention having the above structure will be described below.

The transfer base material sheet on which a release agent layer made of a non-migrating thermosetting resin is formed on one surface is, for example, polyester, vinyl chloride resin, nylon, or polycarbonate, like the transfer base material sheet in a general transfer sheet. It is generally composed of a synthetic resin film such as.

The release agent layer needs to be formed of a non-migrating thermosetting resin so that the release agent layer does not remain on the surface of the ceramic substrate in the transfer step using the transfer sheet,
For example, a polyurethane resin, a melamine resin, a silicone resin or the like is used, and is formed on one surface of the transfer substrate sheet by means of gravure printing, screen printing, roll coating, or the like.

The circuit pattern layer formed on the surface of the release agent layer serves as a circuit pattern layer in the ceramic circuit board, and the circuit pattern layer made of one or more of a resistor portion, a dielectric portion, and a conductor portion, It is formed by a printing means such as screen printing or gravure printing using a printing ink containing glass frit. For example, the resistor portion is a printing ink made of a paste for forming a resistor portion containing powder of a metal oxide such as ruthenium oxide or molybdenum oxide, glass frit and an organic binder, and the dielectric portion is a glass frit. A printing ink comprising a paste for forming a dielectric part containing an organic binder, and further, the conductor part is a paste for forming a conductor part containing a metal powder such as Au, Ag, Cu, a glass frit and an organic binder. It is appropriately formed with a printing ink consisting of. Since the circuit pattern layer formed on the surface of the release agent layer is transferred to the surface of the ceramic substrate and then fired to become a circuit pattern layer formed into a ceramic, the resistor portion, the dielectric portion, The printing ink for forming the conductor portion or the like must be such that the glass frit contained in the printing ink must be one that melts at the above-mentioned firing temperature.
Low melting glass consisting of O78%, SiO ₂ 10%, B ₂ O ₃ 12%, P
bO-B ₂ O ₃ system, PbO-B ₂ O ₃ -Sio _{system, PbO-ZnO-B 2 O} 3 system, PbO
B ₂ O ₃ —Al ₂ O ₃ system, PbO—SiO ₂ —Al ₂ O ₃ —ZnO system glass having a particle size of about _{2 to 30} μm is used.

The heat-sensitive adhesive layer made of a cellulosic resin is completely ashed in the firing step in the method for manufacturing a ceramic circuit board of the present invention, and the amount of oxygen required for ashing is relatively small. It is easily formed by applying and drying the paste by a printing means such as screen printing or gravure printing.

The transfer process, which comprises pressurizing, heating and cooling the superposed body of the transfer sheet and the ceramic substrate having the above-mentioned constitution, is carried out at about 170 to 240 ° C. by a normal pressure or circular pressure method. .

Further, the firing of the ceramic substrate performed after the transferring step is performed by firing the glass frit in the circuit pattern layer such as the resistor portion, the dielectric portion, and the conductor portion transferred to the surface of the ceramic substrate to make the circuit pattern layer ceramic. And firmly adheres to the surface of the ceramic substrate.
It is carried out at about 1000 ° C.

Incidentally, in the method for manufacturing a ceramic circuit board of the present invention having the above-mentioned structure, when transferring the circuit pattern layer in the transfer sheet to the ceramic board, for example, a cellulose resin is previously formed on the surface of the ceramic board onto which the circuit pattern layer is transferred. To form a heat-sensitive adhesive layer, or to preheat the ceramic substrate in advance, or to use both of these means together to make the transfer surface of the ceramic substrate easy to adhere. As a result, a sufficient adhesive ability required between the transfer sheet and the surface of the ceramic substrate that is the surface to be transferred during the transfer step can be easily achieved by the heat-sensitive adhesive layer of the cellulose resin in the transfer sheet. Therefore, it is preferable that the transfer surface of the ceramic substrate is easily adhered by any one of the above means. But is not necessarily required in the ceramic circuit substrate manufacturing method of this easy-adhesion treatment is the invention to poke substrate.

〔Example〕

Hereinafter, a specific configuration of the method for manufacturing a ceramic circuit board of the present invention will be described based on examples.

Example 1 A polyurethane resin was applied to one side of a transfer substrate sheet made of a polyester film having a thickness of 38 μm, heated and cured to form a release agent layer, and then the release agent layer surface was coated with Ag having the following composition. Form a circuit pattern layer corresponding to the conductor portion having a thickness of 15μ by screen-printing with a conductive paste of the system, and further, to cover the circuit pattern layer, an elchicellulose solution on the entire surface of the release agent layer. Apply,
A transfer sheet, which is one example of a transfer sheet used in the method for manufacturing a ceramic circuit board of the present invention, by drying and forming a heat-sensitive adhesive layer having a thickness of about 3 μm with a cellulose resin [A] Got

Ag conductive paste (1) Ag powder ...... 70 parts by weight (2) Lead borosilicate glass frit ...... 10 parts by weight (3) Organic binder consisting of cellulose resin and cellosolve acetate ...... 20 parts by weight Approximately 1μ thick with ethyl cellulose on the transfer surface
After preheating a ceramic substrate consisting of a 96% alumina plate (thickness of about 0.6 mm) on which the heat-sensitive adhesive layer is formed to about 150 ° C, transfer the above-mentioned transfer to the heat-sensitive adhesive layer surface of this ceramic substrate. Transfer sheet [A], the transfer sheet [A]
The heat-sensitive adhesive layer surface is pressed against the surface of the ceramic substrate so that it is heated and pressed for 5 seconds by a flat pressure method at a pressure of 5 kg / cm ² and a temperature of 230 ° C., and after cooling, it is transferred. The transfer substrate sheet and the release agent layer of the sheet were peeled off to obtain a ceramic substrate having the circuit pattern layer of the transfer sheet transferred to the surface thereof.

Further, the ceramic substrate having the circuit pattern layer transferred to the surface was baked at 850 ° C. for 10 minutes to obtain a ceramic circuit substrate [i] as a target product of the method of the present invention.

Example 2 A 96% alumina plate (thickness: about 0.6 m) having a 1 μm-thick heat-sensitive adhesive layer made of ethyl cellulose formed on the transfer surface.
A transfer sheet [A] having the same structure as that used in Example 1 is provided on the surface of the thermosensitive adhesive layer of the ceramic substrate consisting of m), and the thermosensitive adhesive layer surface of the transfer sheet [A] is the ceramic sheet. It is pressed against the surface of the substrate, heated and pressed for 15 seconds by a flat pressure method at a pressure of 4 kg / cm ² and a temperature of 240 ° C., and the same process as the process after the transfer process in Example 1 is performed. As a result, a ceramic circuit board [ii], which was the target product of the method of the present invention, was obtained.

Example 3 A transfer sheet [A] having the same structure as that used in Example 1 was provided on the surface of a ceramic substrate having a thickness of 0.6 mm and made of a 96% alumina plate. The pressure-sensitive adhesive layer surface is pressed against the surface of the ceramic substrate, and is heated and pressed for 30 seconds by a flat pressure method at a pressure of 5 kg / cm ² and a temperature of 240 ° C. The same process as the process was carried out to obtain a ceramic circuit board [iii] as a target product of the method of the present invention.

Example 4 A transfer sheet [A] having the same structure as that used in Example 1 was formed on the embossed surface of a ceramic substrate made of a 96% alumina embossed plate having a thickness of 0.6 mm and having a recessed portion of 0.3 mm. The heat-sensitive adhesive layer surface of the transfer sheet [A] is pressed so that the surface of the ceramic substrate comes into contact with the surface of the ceramic substrate, and heated and pressed for 15 seconds by a flat pressure method at a pressure of 4 kg / cm ² and a temperature of 240 ° C. After that, the same steps as the steps after the transfer step in Example 1 were carried out to obtain a ceramic circuit board [iv] as a target product of the method of the present invention.

[Operation and effect of the present invention]

A method for manufacturing a ceramic circuit board according to the present invention comprises transferring a circuit pattern layer in a transfer sheet having a circuit pattern layer formed by a printing ink containing a glass frit onto a surface of the ceramic board, and then transferring the ceramic board. By firing the substrate at a temperature equal to or higher than the melting point of the glass frit contained in the circuit pattern layer, a ceramic circuit substrate having a ceramic circuit pattern layer on the surface of the ceramic substrate is obtained.

Therefore, in the method of the present invention, the adhesion between the ceramic substrate and the circuit pattern layer is strong, and moreover, the circuit pattern layer is not deformed, such as distorted or twisted, and has good dimensional accuracy and reliability. This has the action and effect of obtaining a high ceramic circuit board. In particular, in the method of the present invention, since the adhesive layer in the transfer sheet is composed of a cellulosic resin, since the adhesive layer is completely ashed during the firing step of the ceramic substrate after the transfer step, distortion is caused. It is a circuit pattern layer which is formed into a ceramics without any cracks and which is excellent in adhesion to the ceramic substrate.

Further, in the method of the present invention, even when a ceramic circuit board having a circuit pattern layer consisting of two or more of a resistor portion, a dielectric portion and a conductor portion is obtained, the circuit pattern layer transferred onto the surface of the ceramic substrate is Since only one firing step is required for forming a ceramic, even when compared with a method for producing a ceramic circuit board, which comprises directly forming a circuit pattern layer on the surface of a ceramic substrate with a firing ink and firing this, Since there is no need to repeat the firing step, the number of steps can be reduced, and thus the operation efficiency is extremely good.

Furthermore, in the method of the present invention, since the mechanism for transferring the circuit pattern layer formed on the transfer sheet to the surface of the ceramic substrate by transfer is used, the surface of the ceramic substrate on which the circuit pattern layer is formed is, for example, It can be applied to shapes other than a flat plate surface such as a convex arc surface, and also for a ceramic circuit board in which a circuit pattern layer is formed across the upper surface and side surfaces of the ceramic board, one transfer step and one transfer step are performed. Since it is only necessary to perform the firing process, there is an effect that the working process is extremely simple.

Claims (4)

[Claims] 1. A transfer base sheet, a release agent layer made of a non-migrating thermosetting resin formed on one side of the base sheet, and a printing ink containing a glass frit on the release agent layer side. A transfer sheet comprising a circuit pattern layer formed by the above, and a heat-sensitive adhesive layer of a cellulose resin formed on the entire surface of the release agent layer so as to cover the circuit pattern layer, On another ceramic board,
The heat-sensitive adhesive layer surface of the transfer sheet is pressed against the ceramic substrate so that it faces the ceramic substrate, and after heating and cooling, the transfer substrate sheet and the release agent layer of the transfer sheet are peeled off to transfer the transfer sheet. Transfer the circuit pattern layer on the sheet to the surface of the ceramic substrate, and after that,
A method of manufacturing a ceramic circuit board, comprising: firing the ceramic board at a temperature equal to or higher than a softening point of a glass frit contained in the circuit pattern layer. 2. The method for manufacturing a ceramic circuit board according to claim 1, wherein the surface of the ceramic substrate to which the transfer sheet is pressed is covered with a heat-sensitive adhesive layer made of a cellulose resin. 3. The method for manufacturing a ceramic circuit board according to claim 1, wherein the ceramic board to which the transfer sheet is pressed is subjected to preheat treatment. 4. The surface of the ceramic substrate, to which the transfer sheet is pressed, has a three-dimensional shape.
Item 4. A method for manufacturing a ceramic circuit board according to Item 2, Item 2 or Item 3.