JPH07122839A - Manufacture of ceramic wiring board - Google Patents

Abstract

PURPOSE:To form a wiring pattern so that a surface is flattened by transferring a wiring pattern-shaped conductor paste dried body formed by using the groove section of a resist onto a ceramic green sheet under pressure. CONSTITUTION:Conductor paste dried bodies 16' are left on a film substrate 11 by using a positive type photo-resist layer 12. The film-shaped base material 11 with the wiring pattern-shaped conductor paste dried bodies 16' is placed so that the conductor paste dried bodies 16' are brought into contact with the surface of the ceramic green sheet 18. The film substrate 11 and the ceramic green sheet 18 are pressed in the thickness direction of the ceramic green sheet 18 by using a normal press molding equipment, etc. The conductor paste dried bodies 16' are buried in the surface of the ceramic green sheet 18, and the surface of the ceramic green sheet 18 is flattened approximately. The film- shaped base material 11 is peeled. Accordingly, wiring patterns can be buried in the surface of a ceramic wiring board so that the surface is flattened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ceramic wiring board, and more particularly to a method for manufacturing a ceramic wiring board used for mounting semiconductor LSIs, chip parts and the like.

[0002]

2. Description of the Related Art In recent years, electronic devices have become smaller and higher in density, and electronic components mounted on these electronic devices have been rapidly made to have a narrower pitch and a larger number of pins, and have a multi-chip structure. Therefore, as a bonding method for LSIs and IC chips, a TAB (Tape Automated Bonding) method or a flip chip method suitable for multi-chip and high-density mounting has been adopted from the conventional wire bonding method. With the increase in the density of such electronic devices, there has been a demand for a technique for forming fine wiring having a line width of 100 μm or less on a ceramic wiring substrate. Hereinafter, a method of forming the conductor wiring on the ceramic substrate will be described as an example.

Conventional methods for forming conductor wiring on a ceramic substrate are roughly classified into a thin film method, a plating method, a thick film method and the like.

In the thin film method, vapor deposition on a ceramic substrate,
This is a method of forming a conductor metal layer having a thickness of several μm by sputtering or ion plating. This method has an advantage that a highly accurate conductor wiring can be formed because a photolithography method using a photoresist can be used. On the other hand, this method has a large number of steps as compared with other methods, the thin film forming apparatus is expensive, etc., resulting in high manufacturing cost,
Further, since the formed wiring layer is thin, it is difficult to pass a large current.

The plating method is a method of forming a conductor wiring on a ceramic substrate by an electrochemical method in a solution, but it has the same problems as the above-mentioned thin film method.

In the thick film method, a conductor paste in which conductor particles are dispersed in an organic vehicle containing a liquid component such as a solvent is used. The conductor paste is screen-printed on a ceramic substrate through a mesh screen and then fired. Is a method of forming a conductor wiring on a ceramic substrate. When the conductor wiring is formed using the thick film method, the substrate does not necessarily have to be a sintered body, and after forming the pattern of the conductor paste on the ceramic green sheet, firing the ceramic green sheet and baking the conductor paste. May be performed at the same time.

Although the thick film method has a great advantage that a conductor wiring having sufficient adhesion strength with a ceramic substrate can be formed at a low cost, this method is a method of forming a conductor wiring on a sintered body. When applied to, since the liquid component is not absorbed inside the sintered body, the liquid component in the printed conductor paste spreads laterally, so-called "bleeding" or "drip" phenomenon occurs, It is impossible to form a thick film conductor wiring having a width or a space between wirings of 150 μm or less as designed.

On the other hand, when this method is applied to the above-mentioned method for forming conductor wiring on the ceramic green sheet, the liquid component in the printed conductor paste is well absorbed inside the ceramic green sheet in a short time,
No "bleeding" or "who" phenomenon occurs. Further, the ceramic green sheet shrinks by about 82% by normal firing, and the width of the wiring also shrinks at the same time. Because of these advantages, in the method of forming the conductor wiring on the ceramic green sheet, the width of the wiring and the distance between the wirings are 150 μm.
The following fine conductor wiring can be formed.

However, when the conductor paste is printed by screen printing, the flatness of the applied conductor paste is reduced because the cross section of the conductor paste has a chevron shape. Therefore, when the TAB bonding is performed using the ceramics substrate on which the conductor wiring pattern is formed by the above method, there is a problem that a bonding area becomes small and a bonding failure easily occurs.

Further, as the number of times of printing increases, the conductive paste wraps around the back surface of the screen, and the excess conductive paste adheres to the surface of the ceramic green sheet, causing a short circuit between the wirings of the obtained sintered body. there were.

[0011]

Therefore, in recent years, photolithography using a photoresist, which is a feature of the thin film method, is introduced to form a conductor wiring pattern, and the conductor wiring itself is a feature of the thick film method. Attempts have been made for a method of forming using paste.

In Japanese Unexamined Patent Publication No. 4-283946, after forming a photoresist layer on the surface of a ceramic green sheet, a groove portion is formed in a conductor wiring pattern on the photoresist layer by photolithography, and a conductor paste is applied to the groove portion. There is described a method in which a conductive wiring pattern is formed on a ceramics substrate by rubbing it in to fill it, then developing the photoresist layer to remove it, and firing it.

However, according to this method, the photoresist is dissolved in the ceramic green sheet, and when the photoresist is dissolved and removed by the developing solution, the ceramic green sheet is also dissolved and the binder contained in the ceramic green sheet is easily eluted. There were challenges.

Further, in the method described in the above-mentioned Japanese Patent Laid-Open No. 4-283946, since the formed conductor wiring pattern rises up high on the ceramic green sheet,
When the layers are laminated, distortion is caused between the laminated ceramic green sheets, and when the laminated body is fired, defects such as delamination and warp are likely to occur in the manufactured ceramic substrate.

Further, if the conductor wiring is formed in a convex shape on the surface of the ceramic substrate, it is difficult to fix the wiring when connecting with other electronic parts, and it is easy to be damaged. .

The present invention has been made in view of the above problems, and by increasing the flatness of the surface of the ceramic green sheet including the pattern of the conductor paste to be formed, the wiring pattern has a flat surface. It is an object of the present invention to provide a method for manufacturing an inexpensive ceramic wiring substrate that is embedded in a substrate, has a highly precise and fine wiring pattern, is free from defects such as short circuit, delamination, and warp, and is less likely to cause disconnection.

[0017]

In order to achieve the above object, a method for manufacturing a ceramic wiring board according to the present invention comprises a photoresist layer forming step of forming a positive photoresist layer on the surface of a film-shaped substrate, A groove portion forming step of forming a wiring pattern groove portion in the positive photoresist layer by subjecting the positive photoresist layer to an exposure treatment and a development treatment, and an entire surface exposure treatment to the photoresist layer in which the groove portion is formed. Performing a whole surface exposure treatment step, a conductor paste filling step of filling the groove portion with a conductor paste, a drying step of drying the conductor paste filled in the groove portion, and a developing treatment of the positive photoresist layer. A photoresist layer disappearing step of disappearing the positive photoresist layer, and a step of forming on the film-shaped substrate by the above step. A pattern transfer step of transferring the wiring pattern-shaped conductor paste dried body to a ceramic green sheet by pressure and peeling off the film-shaped substrate, and a firing step of firing the ceramic paste green sheet to which the conductor paste dried body is transferred. It is characterized by including (1).

The method for manufacturing a ceramic wiring board according to the present invention comprises a photoresist layer forming step of forming a positive photoresist layer on the surface of a film-shaped substrate, and an exposure treatment and a development treatment on the positive photoresist layer. By applying a groove portion forming step of forming a wiring pattern groove in the positive photoresist layer, a conductor paste filling step of filling the groove portion with a conductor paste, and drying the conductor paste filled in the groove portion. A drying step to
A whole surface exposure treatment step of subjecting the positive photoresist layer to a whole surface exposure treatment, and a photoresist layer disappearance in which the positive photoresist layer is subjected to a development treatment to disappear the positive photoresist layer A step, a pattern transfer step of pressure-transferring a wiring pattern-shaped conductor paste dried body formed on the film-shaped substrate by the step to a ceramic green sheet, and peeling the film-shaped substrate; A firing step of firing the ceramic green sheet to which the paste dried body is transferred is included (2).

The method of manufacturing the ceramic wiring board described in (1) above will be described below with reference to FIGS.

First, as a photoresist layer forming step, the positive type photoresist layer 12 is formed on the surface of the film-shaped substrate 11.
Are formed (FIG. 1A).

As the film-shaped substrate 11, a flexible material such as polyester or polyethylene is used to facilitate the peeling of the film-shaped substrate 11 from the ceramic green sheet 18 in the transfer step (FIG. 1 (h)) described later. The resin film having is preferable. Further, for the above reason, a resin film-shaped substrate 11 coated with a release agent such as silicone oil may be used.

The method of forming the positive photoresist layer 12 is not particularly limited, and a method of forming the positive photoresist layer 12 by adhering a positive photoresist film to the film substrate 11 may be used. However, using a liquid positive photoresist, for example, after coating the liquid photoresist on the ceramic substrate 11 by a roll coater method, a bar coater method, a spin coater method, a dip method, etc., it is put in an oven and the temperature is 85 to 90. The method of forming the solid positive photoresist layer 12 by drying by heat treatment at 30 ° C. for about 30 to 40 minutes is more preferable from the viewpoint that the horizontal positive photoresist layer 12 can be formed. Among the above-mentioned coating methods, the roll coater method or the bar coater method is preferable because it can form a film having a uniform thickness. Examples of the liquid photoresist include AZ490 manufactured by Hoechst Japan Co., Ltd.
3, AZ4620A, OP resist made by Tokyo Ohka Kogyo Co., Ltd., Accutrace made by Tokyo Electron, Probimer made by Ciba-Geigy Japan, and the like.

The thickness of the positive photoresist layer 12 formed is preferably 25 to 50 μm. When the thickness of the positive photoresist layer 12 is less than 25 μm, it becomes difficult to fill the conductive paste 16 in the groove portion 15 formed in the positive photoresist layer 12 in the subsequent step, while the thickness of the positive photoresist layer 12 is decreased. When the thickness exceeds 50 μm, the conductor layer forming pattern-shaped groove portion 15 is formed in the case where development processing is performed in a later step.
Is difficult to form completely. In the case where a negative photoresist is used, it is difficult to eliminate the photoresist due to development in the later-described photoresist layer disappearance step, which is not preferable.

Next, as a groove forming step, the positive type photoresist layer 12 is exposed to ultraviolet rays 13 through a photomask 14 (FIG. 1B), and then developed to obtain a positive type photoresist. A wiring pattern groove 15 is formed in the layer 12 (FIG. 1C).

The conditions of the exposure process and the development process are not particularly limited, and are generally the same as the conditions under which the positive photoresist layer 12 is exposed to the ultraviolet ray 13 through the photomask 14 in the process of a substrate or the like. The exposure process can be performed under the conditions, and the subsequent development process can also be performed under the normal conditions.

In this groove forming step, the width is 30 to 50.
It is possible to form the groove portion 15 in the positive photoresist layer 12 with the distance between the groove portions approaching each other by about 25 μm to about 50 μm by about μm.

Next, as a whole surface exposure processing step, the whole surface exposure processing is performed on the positive type photoresist layer 12 in which the groove portion 15 is formed (FIG. 1D).

The purpose of performing the whole surface exposure treatment is to dissolve and eliminate the positive photoresist layer 12 by performing a development treatment in a later step.

The conditions of the exposure process with the ultraviolet rays 13 are not particularly limited, and the conditions can be the same as the conditions when the exposure process is usually performed on the positive photoresist layer 12.

Next, in the conductor paste filling step, the conductor paste 16 is filled in the groove portion 15 formed in the positive photoresist layer 12 (FIG. 1E).

As the conductor for forming the wiring pattern, a known conductor material usually used for wiring such as a ceramic substrate can be used, and specific examples thereof include W, Mo-Mn, Au, Ag-. Examples thereof include Pd and Cu. In the present invention, the positive photoresist layer 1 is formed in a later step.
Since there is no step of decomposing and eliminating 2 by firing, an inexpensive conductor material such as Cu described above can be used, and a wiring pattern can be formed at low cost.

As the solvent of the conductor paste 16, it is necessary to use a solvent that does not dissolve the positive photoresist layer 12. This is because when the conductor paste 16 is prepared using a solvent that dissolves the positive photoresist layer 12, when the groove 15 of the positive photoresist layer 12 is filled with the conductor paste 16, the positive photoresist layer 12 becomes the solvent. The shape of the groove 15 is dissolved and the shape of the groove 15 collapses. Examples of the solvent that does not dissolve the positive photoresist layer 12 include hydrocarbon solvents such as toluene, xylene, camphor oil, turpentine oil, and pine oil.

Further, the resin (binder) used for the conductor paste 16 needs to be one that does not dissolve in the developer used in the subsequent step. This is because the solvent remaining in the step of filling the groove portion 15 formed in the positive photoresist layer 12 with the conductor paste 16 and drying it, and then dissolving and eliminating the positive photoresist layer 12 by contacting it with a developing solution. This is to prevent the conductor paste 16 from being dissolved in the developing solution. Since the developing solution is usually an aqueous solution, the resin used for the conductor paste 16 needs to be a water-insoluble resin. Specific examples of the resin include ethyl cellulose, acrylic resin, methacrylic resin and the like.

For the above reasons, the conductor paste 16 used in the present invention contains, for example, 80 to 92 of the above conductor powder.
It is preferable that the composition has a composition including wt%, 2 to 6 wt% of the resin such as the acrylic resin, and 2 to 18 wt% of a solvent such as toluene. In addition, materials such as glass and ceramics for improving the adhesion to the substrate. May be added in a small amount.

As a method for filling the groove portion 15 of the photoresist layer 12 with the conductor paste 16 having the above-described composition, a spatula 17 made of fluororesin or rubber is used as shown in FIG. The spatula 17 holding 16 may be moved while being in contact with the surface of the positive photoresist layer 12, and the conductor paste 16 may be rubbed directly into the groove 15. When the conductor paste 16 remains on the surface of the positive photoresist layer 12 other than the groove portion 15, it can be almost removed by scraping it with a spatula 17 to which the conductor paste 16 is not attached. Furthermore, when there is an extremely thin layer of the conductor paste 16 that cannot be removed by the above operation, it can be removed by drying the conductor paste 16 and then polishing it with a wrapping film. This prevents the conductor paste 16 from adhering to other parts than the wiring part of the ceramic green sheet 18 in the pattern transfer step described later, and thus causing a short circuit in the sintered body.

Next, as a drying step, the conductor paste 16 filled in the groove portion 15 is heat-treated and dried.

In this step, the solvent component in the conductor paste 16 is evaporated so that the dried conductor paste is not dissolved in the developing solution in the next photoresist layer disappearing step.

After that, as a photoresist layer disappearing step,
By subjecting the positive photoresist layer 12 to development processing, the positive photoresist layer 12 disappears, and the conductor paste dried body 16 ′ is left on the film substrate 11 (FIG. 1).
(F)).

In the above-mentioned exposure process, the positive photoresist layer 12 has been subjected to the exposure process. Therefore, the positive photoresist layer 12 is dissolved in the developer by performing the development process with the developer. Then disappears. No special condition is required as the condition for the developing treatment, and a normal condition may be used. In addition, since the water-insoluble resin is used as the binder of the conductor paste 16, the shape of the conductor paste dried body 16 'formed in the wiring pattern does not collapse.

The conventional method of removing the positive type photoresist layer 12 by burning it in an oxidizing atmosphere cannot be adopted in the present invention because the film-shaped substrate 11 decomposes and disappears. However, the method of the present invention in which the positive photoresist layer 12 is dissolved and eliminated by a wet method does not cause the conductor to be oxidized as compared with the conventional combustion method, and an inexpensive metal can be used as the conductor. Has the advantage.

Next, as a pattern transfer step, the film-shaped substrate 1 is obtained by passing through the photoresist disappearance step.
The conductor-patterned dried body 16 'of the wiring pattern formed on 1 is pressure-transferred onto the ceramic green sheet 18 (Fig. 1 (g)), and then the film-shaped substrate 11 is peeled off (Fig. 1 (h). )).

The pressure transfer can be actually performed by the following method. First, the film-shaped substrate 11 having the wiring pattern-shaped conductor paste dried body 16 ′ is placed so that the conductor paste dried body 16 ′ contacts the surface of the ceramic green sheet 18. Next, the ceramic green sheet 18 is pressed in the thickness direction using, for example, an ordinary press molding device. As for the pressurizing condition at this time, the pressure is preferably about 10 to 100 kg / cm ² , and the time for maintaining the pressure is preferably about 1 to 2 minutes. At this time, in order to increase the plasticity of the ceramic green sheet 18, it may be heated to about 100 ° C.

The ceramic green sheet 18 used in the present invention includes, for example, a ceramic powder such as alumina, mullite, glass ceramics, aluminum nitride, etc., a sintering aid, polyvinyl butyral (PVB), and a binder such as acrylic resin. Solvents such as toluene, xylene, isobutyl alcohol, dibutyl phthalate (DB
P) and other plasticizers are added and mixed to form a slurry,
It is formed by molding by a doctor blade method or the like and then drying. As described above, the ceramic green sheet 18 is relatively flexible because the plasticizer is added thereto. On the other hand, a wiring pattern-shaped conductor paste dried body 16 ′ formed on the film-shaped substrate 11
Since it does not contain a plasticizer, it is harder than the ceramic green sheet 18, and the conductor paste dried body 16 ′ is embedded in the surface of the ceramic green sheet 18 in the pressure transfer step as shown in FIG. The surface of the ceramic green sheet 18 becomes almost flat. Therefore, by peeling the film-shaped substrate 11 after this,
As shown in FIG. 1 (h), it is possible to obtain the ceramic green sheet 18 in which the conductor paste dried body 16 ′ is embedded and the surface is flat.

Next, in the firing step, the ceramic green sheet 18 to which the dried conductor paste 16 'is transferred.
To bake. It should be noted that, before the firing step, the ceramic green sheet 18 to which the dried conductor paste 16 ′ was transferred
You may form the ceramic green sheet laminated body (henceforth a laminated body) containing at least 1 layer.

The type of ceramic green sheet constituting this laminated body is not particularly limited, and other ceramic green sheets or the like may be used according to the purpose in addition to the ceramic green sheet 18 obtained by the above method. As a method of forming the laminated body, a method of hot pressing after stacking the ceramic green sheets 18 and the like can be mentioned. Examples of the structure of the laminated body include, for example, a stack of several ceramic green sheets 18 having the same wiring pattern or different wiring patterns obtained by the above method, or a ceramic green sheet 18 obtained by the above method and another wiring pattern. Examples thereof include a laminate of a ceramic green sheet or the like on which the above are not formed. The ceramic green sheet 18 and the like may be provided with various through holes such as via holes if necessary.

In the firing step, the ceramic green sheet 18 or the laminate (hereinafter referred to as the ceramic green sheet 18) is fired to decompose and eliminate the organic components contained in the ceramic green sheet 18 and the ceramic powder. Then, the conductor is sintered to complete the production of the ceramic wiring board having a wiring pattern on the surface or inside thereof.

The firing conditions differ depending on the types of ceramics and conductors in the ceramic wiring board to be manufactured, the types of organic components contained in the green sheet 18 etc. before firing, but the organic components contained in the green sheet 18 etc. are sufficient. It is necessary that the conductor material is not decomposed and disappears, the conductor material is not oxidized, and the conductor and the ceramic powder are sufficiently sintered. Usually, firing is performed in a neutral atmosphere containing an inert gas such as nitrogen or in a reducing gas atmosphere containing the inert gas, hydrogen, steam and the like.

In the firing step, the dried conductor paste 1
6'is embedded in the surface of the ceramic green sheet 18 or the like, and the surface of the ceramic green sheet 18 is flat.
Since the wiring is embedded without protruding from the surface, it is possible to manufacture a ceramics wiring board having a flat surface.

Further, using a laminated body of green sheets,
When manufacturing a ceramic wiring board, distortion does not occur between each ceramic green sheet in the stacking process, and uneven shrinkage due to strain does not occur in the baking process as well. There is no such defect.

Next, a method of manufacturing the ceramic wiring board described in (2) above will be described. In the method for manufacturing a ceramic wiring board described in (2) above, except that the entire surface exposure treatment step is changed after the drying step, there is no difference from the method for manufacturing a ceramic wiring board described in (1) above, and The method and conditions are the same as the method described in (1) above.

[0051]

According to the method of manufacturing a ceramic wiring board described in (1) above, the positive type photo resist is formed by the photoresist layer forming step, the groove forming step, the whole surface exposure processing step and the conductor paste filling step. The groove 15 formed in the resist layer 11 is filled with the conductor paste 16, and the conductor paste 16 filled in the groove 15 does not cause bleeding or the like.

In the photoresist layer disappearing step, the positive type photoresist layer 12 can be disappeared by a wet method at low cost.

In the conductor paste filling step, the conductor paste 16 is filled only in the groove portions 15 formed in the positive photoresist layer 12, so that in the pattern transfer step, except the wiring pattern on the surface of the ceramic green sheet 18. The conductor paste 16 does not adhere to the portion, and a short circuit does not occur in the ceramic wiring board after firing.

In the pattern transfer step, since the film-shaped substrate 11 having the conductor paste dried body 16 'is placed on the surface of the ceramic green sheet 18 and pressed, the conductor paste dried body 16' becomes the surface of the ceramic green sheet 18. Embedded in the ceramic green sheet 1
The flatness of the surface of No. 8 is extremely high, and no distortion occurs between the ceramic green sheets even in the laminating step.

Then, by going through the firing step,
A wiring pattern is embedded in the surface so that the surface becomes flat, and has a highly precise and fine wiring pattern on the surface and inside, and is free from defects such as short circuit, delamination, warpage, etc. The substrate is cheaply manufactured.

Also in the method for manufacturing a ceramics wiring substrate described in (2) above, the same operation is performed in each step except that the order of the entire surface exposure processing steps is different, and the wiring pattern has a flat surface. Buried in the surface,
A ceramic wiring board having a highly precise and fine wiring pattern on the surface or inside thereof, having no defects such as short circuit, delamination, warp, and less likely to cause disconnection can be manufactured at low cost.

[0057]

EXAMPLES AND COMPARATIVE EXAMPLES Examples and comparative examples of the ceramic wiring board according to the present invention will be described below.

[Example 1] A liquid positive photoresist (AZ4903 manufactured by Hoechst Japan Co., Ltd.) was coated on the surface of a film-shaped substrate (made by Toyo Metallizing Co., Ltd.) made of polyester with a roll coater, and the temperature was 90 ° C.
It was dried by putting it in the oven kept at. The thickness of the positive photoresist layer after drying is 25 μm
Met. Next, the line width is 50 μm and the pitch between the wirings is 1
The positive photoresist layer was irradiated with ultraviolet rays through a photomask having a predetermined wiring pattern of 00 μm under an exposure amount of 3000 mJ / cm ² .

Next, the film-like substrate having the positive photoresist layer which has been exposed to light is immersed in a developing solution (AZ400K manufactured by Hoechst Japan Ltd.) and shaken to develop the film-like substrate. Grooves were formed in a wiring pattern on the positive photoresist layer formed on the material.

Next, the exposed film-like substrate was placed on a hot plate kept at 120 ° C. for about 30 minutes.
After heating for 2 seconds, the exposure amount of ultraviolet rays is 3000 mJ / cm ²
The entire surface was irradiated under the conditions of.

Next, using a spatula made of fluororesin, W powder having an average particle diameter of 2 μm: 92 wt%, acrylic resin: 3
wt% and turpentine oil: 5 wt% While holding the conductor paste, the spatula is moved horizontally so as to contact the surface of the positive photoresist layer,
The conductor paste was rubbed into the groove formed in the positive photoresist layer.

In the step of filling the conductive paste, since the conductive paste remained on the surface of the positive photoresist layer other than the groove, it was scraped off using a spatula made of fluororesin to which the conductive paste was not attached.

Next, the conductor paste filled in the groove was heated to 90 ° C. to dry the conductor paste.

An extremely thin conductor paste of about one particle layer, which could not be removed even by scraping off the excess conductor paste with the spatula, was dry-deposited on the surface of the positive photoresist layer other than the groove. Therefore, it was removed by polishing with an alumina wrapping film (manufactured by Sumitomo 3M Co., Ltd.) coated with abrasive grains having an average particle diameter of 1 μm for about 10 seconds.

Next, the film-shaped substrate after the above treatment is dipped in a developer (AZ400K manufactured by Hoechst Japan) and shaken to dissolve and remove the positive photoresist layer, and the dried conductor paste is obtained. Only left on the film substrate.

Apart from the above steps, a mixture of alumina powder and a sintering aid (94 wt% as alumina content) 1
To 100 parts by weight, 13 parts by weight of methacrylic acid ester resin as an organic binder, 5 parts by weight of dioctyl phthalate as a plasticizer, and 27 parts by weight of toluene and isopropyl alcohol as a solvent were added and mixed, and the doctor blade method was used. To form a tape, and the tape was dried to produce an alumina ceramic green sheet. Subsequently, a via hole was formed in this alumina ceramic green sheet using a punching die.

Next, the dried conductor paste formed on the film substrate is placed on the film substrate so as to be in contact with the surface of the alumina ceramic green sheet, and this is heated by a press molding machine. Was added while pressing, and the dried body of the conductor paste was pressure-transferred onto the alumina ceramic green sheet. The pressure transfer conditions are a pressure of 20 kg / cm ² and a temperature of 90 ° C.
This pressurized state was maintained for 30 seconds. Then, the film substrate was peeled off, and only the dried conductor paste was left on the alumina ceramic green sheet.

Then, the via holes in the alumina ceramic green sheet were filled with a conductive paste by a usual screen printing method.

The alumina ceramic green sheet on which the conductor pattern was formed by the above-mentioned method was replaced with 100 to 1
Nitrogen: 50v by thermocompression-bonding multiple sheets with a 20 ° C hot press
ol%, hydrogen: in an atmosphere gas of 50 vol%, 1500
The alumina ceramic wiring board was formed by firing at 1600C to 1600C.

The line width of the wiring formed on the alumina ceramic wiring substrate after firing was 40 μm, and the minimum value of the distance between the wiring was 25 μm. The cross-sectional shape of the wiring was rectangular when observed by a scanning electron microscope (SEM). Met. Moreover, it was found from the SEM and visual observation that there were no defects such as short circuit, delamination, and warpage.

Example 2 As a conductive paste, Ag powder having an average particle size of 2 μm: 85 wt%, acrylic resin: 4
wt% and turpentine oil: 11 wt% Ag conductor paste was used, and alumina powder (60 wt%) and glass powder (CaO-Al ₂ O) were used as the ceramic green sheets.
_3- B ₂ O ₃ —SiO ₂ system 40 wt%) as a raw material, 100 parts by weight of the ceramic powder mixture, 13 parts by weight of a methacrylic acid ester resin as an organic binder, 5 parts by weight of dioctyl phthalate as a plasticizer,
A ceramic wiring board was prepared in the same manner as in Example 1 except that a ceramic green sheet prepared by adding toluene and isopropyl alcohol as a solvent in a total amount of 27 parts by weight was used and baked at 890 ° C. in the atmosphere. Was manufactured.

The line width of the wiring formed on the ceramic wiring board after firing is 40 μm, and the minimum value of the distance between the wirings is 25.
μm, and the cross-sectional shape of the wiring is determined by a scanning electron microscope (SE
It was rectangular when observed under M). Also, the S
By EM and visual observation, it was found that there were no defects such as short circuit, delamination, and warpage.

As described above, in the method for manufacturing a ceramic wiring board according to the embodiment, the wiring pattern is embedded in the surface so that the surface is flat, and the wiring pattern is highly precise and fine on the surface or inside. It is possible to inexpensively manufacture a ceramics wiring board which has no defects such as short circuit, delamination, and warp and is less likely to cause disconnection.

[Comparative Example 1] In the photoresist layer forming step, silicon oil was applied to the surface of the film-shaped substrate, and then liquid photoresist was applied in the same manner as in Example 1 to perform the pattern transfer step of the dried conductor paste. At
An alumina ceramic wiring board was manufactured by the same method and conditions as in Example 1 except that the conductor paste was transferred by lightly pressing at a temperature of 90 ° C. with almost no pressure applied.

The line width of the wiring formed on the alumina ceramic wiring substrate after firing was 40 μm, and the minimum value of the distance between the wirings was 25 μm, and the cross-sectional shape of the wiring was observed by a scanning electron microscope (SEM). It was a rectangle.
However, it was found from the above SEM and visual observation that voids were formed at the wiring ends and that delamination was partly generated.

[0076]

As described above in detail, in the method for manufacturing a ceramic wiring board according to the above (1) to (2) of the present invention, the wiring pattern is buried in the surface so that the surface becomes flat. Thus, it is possible to inexpensively manufacture a ceramic wiring board having a highly precise and fine wiring pattern on the surface or inside and having no defects such as short circuit, delamination, and warp. Thus, the ceramic wiring board obtained by the method for manufacturing a ceramic wiring board according to the present invention,
Since the wiring does not project to the surface, the wiring can be easily fixed and connected when connecting with electronic parts, disconnection is unlikely to occur, and the number of internal defects is extremely low, so high A ceramic wiring board can be manufactured with a high yield.

[Brief description of drawings]

1A to 1H are cross-sectional views schematically showing each step in a method for manufacturing a ceramic wiring board according to the present invention.

[Explanation of symbols]

 11 film-like base material 12 positive type photoresist layer 15 groove part 16 conductor paste 16 'conductor paste dried body 18 ceramics green sheet

Front Page Continuation (72) Inventor Koichi Uno 2701-1 Iwakura, Omine-cho, Mine City, Yamaguchi Prefecture Sumitomo Metal Ceramics Co., Ltd. (72) Inventor Yoshikazu Nakata 4-53-3 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Sumitomo Metal Industries, Ltd.

Claims (2)

[Claims] 1. A photoresist layer forming step of forming a positive photoresist layer on the surface of a film-like substrate; and an exposure treatment and a development treatment of the positive photoresist layer to obtain the positive photoresist layer. A groove forming step of forming a wiring pattern-like groove on the substrate, a whole surface exposure processing step of performing a whole surface exposure processing on the positive photoresist layer in which the groove portion is formed, and a conductor paste filling step of filling the groove portion with a conductor paste. A drying step of drying the conductor paste filled in the groove, a photoresist layer disappearing step of developing the positive photoresist layer to remove the positive photoresist layer, and the step of The dried conductor paste in the form of wiring pattern formed on the film substrate is pressed onto the ceramic green sheet. A method of manufacturing a ceramic wiring board, comprising: a pattern transfer step of transferring and peeling the film-shaped base material; and a baking step of baking the ceramic green sheet on which the dried conductor paste is transferred. 2. A photoresist layer forming step of forming a positive photoresist layer on the surface of a film-shaped substrate; and an exposure treatment and a development treatment of the positive photoresist layer, whereby the positive photoresist layer is formed. A groove portion forming step of forming a wiring pattern-shaped groove portion on the conductor pattern; a conductor paste filling step of filling the groove portion with a conductor paste; a drying step of drying the conductor paste filled in the groove portion; and the positive photoresist layer. A whole surface exposure treatment step of subjecting the whole surface to an exposure treatment, a photoresist layer disappearance step of developing the positive photoresist layer subjected to the whole surface exposure surface to eliminate the positive photoresist layer, and The dried conductor paste of the wiring pattern formed on the film-shaped substrate was added to the ceramic green sheet. A method of manufacturing a ceramic wiring board, comprising: a pattern transfer step of transferring by pressure and peeling off the film-shaped substrate; and a firing step of firing the ceramic green sheet to which the dried conductor paste is transferred.