JPH0653653A - Manufacture of ceramic multilayer wiring board - Google Patents

Abstract

PURPOSE:To eliminate defective filling of conductor paste in through hole and short-circuit of through hole with conductor paste during the printing of wirings by using a solvent of conductor paste mixing particular raw materials. CONSTITUTION:A solvent of conductor paste mixing alpha-terpineol of 31 to 100w.%, diethylenegrycol of 0 to 69wt.% and monobuthyl ether acetate (nBCA) is used. A green sheet 1 in the thickness of 0.1 to 0.2mm is cut and through holes 2 (diameter of 0.05 to 0.1mm) are formed at the lattice points. It is difficult to form a through hole 2 when diameter is less than phi0.05 mm and cavity is generated when the diameter is larger than phi0.1mm. Filling of conductor paste to the through holes 2 and conductor wiring 3 in the direction of flat surface between the through holes 2 are conducted simultaneously on the same screen plate. Thereby, filling of conductor of the through holes 2 can be conducted easily and disconnection or short-circuit failure of wiring conductor 3 can be reduced. Moreover, the screen plate can be reduced and manufacturing steps can also be saved.

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 multilayer wiring board by a sheet laminating method using a water-soluble binder.

[0002]

2. Description of the Related Art Conventional ceramic multi-layer wiring boards are made by dissolving butyral resin or acrylic resin in an organic solvent such as trichloroethylene or methyl ethyl ketone, and mixing and dispersing ceramic powder into the slip to slip from a knife edge called doctor blade method. Is poured onto a carrier film to form a sheet having a thickness of 0.2 to 0.3 mm. This unsintered green sheet is called a green sheet, and this green sheet has a diameter of 0.13-0.2 with a grid spacing of about 0.5 mm.
mm through hole is formed by NC punch or drilling machine.
After the conductor paste is filled in the through holes, wiring is printed. The required number (6 to 50) of green sheets with conductor wiring are aligned and laminated, and then thermocompression bonded by hot pressing and sintering is performed. In this method, defective filling of the conductive paste into the through holes and poor electrical continuity due to volume contraction during sintering occur. As a method for solving this problem, JP-B-63-40325, JP-A-63-133597, JP-A-63-204792 and JP-A-64
-61990, and further, JP-A-1-281795. For example, in JP-A-64-61990,
As shown in FIG. 2, the vacuum suction force of the table (printing stage) on which the green sheet is placed is controlled to uniformly print the conductor paste (3) on the wall surface (2) of the through hole. Japanese Patent Laid-Open No. 1-281795
In the publication, as shown in FIG. 3, the surface of the green sheet is masked with a metal foil (4), and then a through hole (2) is formed and then filled with a conductor paste. The mask (4) is peeled off at the time of stacking to prevent blurring during printing. Further, in Japanese Patent Laid-Open No. 63-133597, as shown in FIG. 4, the conductor filled in the through hole (2) of the sintered substrate has a cavity shown in (a) due to dry sintering shrinkage after printing. 2 (2) at the center of the through hole after filling the conductor paste.
Make a hole with the same shape as. JP-B-63-40325 describes that a gelling agent is added to a through-hole filling paste to prevent conductor shrinkage during drying and sintering. However, in the case of these methods, interlayer peeling is likely to occur during thermocompression bonding due to the solvent filled in the cavities of the through holes. When forming a through hole after masking with metal foil, the diameter used for forming the through hole is about 0.1 mm
Drills and pins are easily broken, and scraps of metal foil are easily clogged in the through holes. When the paste containing the gelling agent is used, the filling is good, but as shown in FIG. 5 (b), the paste filled in the through holes (2) protrudes from the sheet surface, so that the next wiring is printed. As shown in FIG. 5 (c), the screen plate surface and the green sheet surface are not in close contact with each other, and the wiring conductor (3) is liable to be bleeding. is there.

[0003]

The above-mentioned prior art does not consider the manufacturing process or mass productivity. The present invention is suitable for mass production of a ceramic multilayer wiring board, in consideration of mass productivity, in order to prevent defective filling of the conductive paste into the through holes and short circuit with the conductive paste in the through holes during wiring printing. It is to provide a substrate manufacturing method.

[0004]

In order to achieve the above object, a conductive paste that is easy to fill and a through-hole shape, and a printing method that does not misalign with a paste that is difficult to blur in wiring printing are required. First, the relationship between the filling property of the conductor paste and the shape of the through hole was examined. As a result, when the through hole diameter is φ0, 13 mm or more, the paste containing the gelling agent is suitable. However, at φ0.1-0.05mm,
In the case of the paste to which the gelling agent is added, the flow of the paste is stopped in the middle of the through hole without filling the entire through hole. On the other hand, in the case of the conductor paste without the addition of the gelling agent, the conductor contracts in the through hole of φ0, 13 mm to 0.2 mm, and the filling state is good in the through hole diameter of φ0.05 to 0.1 mm, The paste adheres to the surface of the printing stage, and when the green sheet is taken out of the printing stage, the paste in the through holes on the side of the printing stage is taken to the side of the printing stage, causing a depression of 20 to 30 μm.
Therefore, even if the paste on the printing stage surface was wiped off, it was found that the paste powder adhered to the next printed green sheet surface, and the use of a release film was examined. In the case of a green sheet using a water-soluble binder, the permeability, swelling or solubility in the sheet differs depending on the solvent, so it is necessary to select a solvent suitable for the green sheet using a water-soluble binder as the solvent for the conductor paste. Is.

From the above results, the size of through-holes in which the conductor paste can be easily filled, the raw material composition of the conductor paste that allows the filling and wiring printing to be performed simultaneously, the selection of a solvent having a small dimensional change or sheet strength change after printing, and the adhesion of the paste are prevented. The release film was selected and the substrate manufacturing method was determined.

[0006]

By reducing the diameter of the through hole, the amount of the conductive paste to be filled can be reduced, and the volume contraction during drying and sintering is small, so that no electrical conduction failure occurs. In addition, by selecting the solvent for the conductor paste and optimizing the mixture of paste raw materials, simultaneous filling and wiring printing can be realized, and since printing misalignment and printing blurring are small, the conductor paste filled in the through holes and the conductor printed with wiring can be realized. Short circuit can be prevented. Further, by using the release film, since the conductor paste layer does not adhere to the green sheet, it is possible to prevent a short circuit between the through hole and the wiring filled in the opposing sheet caused by the adhesion of dust.

[0007]

EXAMPLES Examples of the present invention will be described in detail below.

Example 1 A raw material powder for producing a mullite ceramic substrate composed of mullite, silica, magnesia, and alumina was mixed with an acrylic water-soluble binder, a dispersant or a defoaming agent, and water to prepare a slurry, and then a doctor blade. Thickness by law
A green sheet of 0.1 to 0.2 mm was produced. This green sheet is cut into 200 to 450 mm square, flattened by hot press if necessary, fixed to a jig used in the subsequent process, and then through holes required for electrical connection between layers with NC punch etc. (Hole diameter 0.05 to 0.1 mm) was formed at grid points of 0.3 mm pitch. If the diameter of the through hole is φ0.05 mm or less, it is difficult to make a hole, and if it is φ0.1 mm or more, a cavity occurs. The filling of the conductor paste in the through holes and the conductor wiring in the plane direction between the through holes were simultaneously performed on the same screen plate. In this printing method, first, regenerated cellulose or a film coated with regenerated cellulose or acetyl cellulose on a stage on which a printed material is placed, smooth paper containing ceramic powder or synthetic resin, or a filter film with synthetic resin holes is used. Place the green sheet with through holes formed on this film, accurately align the screen plate and the through hole with an automatic positioning device, and then perform squeezing. The film (film placed on the printing stage) is peeled off, and the cross-sectional shape shown in FIG. 1 is obtained. The paste used for this printing has the following raw material composition.

W powder 80-94 wt% Vehicle 6-20 wt% Vehicle is a binder such as ethyl cellulose, oil-soluble acrylic resin, butyral resin in the following solvent 6-14 wt%
% Dissolved and used.

Α-Terpineol 31 to 100 wt% nBCA 0 to 69 wt% W powder has a low paste viscosity at 80 wt% or less, resulting in poor filling into through holes. At 94 wt% or higher, the paste viscosity is high and poor filling occurs. Breakage of conductor wiring occurs. As shown in FIG. 6, the proportion of solvent used in the vehicle is α.
When the proportion of terpineol is 30 wt% or less, the breaking load of the green sheet is rapidly reduced to 80 to 120 g / cm ^2, and the green sheet is torn when the screen plate separates from the green sheet (plate separation) after squeezing in the printing process. , Easy to tear while handling the green sheet after printing. If the proportion of α / terpineol is close to 100 wt%, the paste may scatter when the plate is released, depending on the proportion of W powder and the binder, so 0.2-10 wt% of plasticizer (dibutyl phthalate, dioctyl phthalate, etc.) % May be added. In addition, if the paste fluidity changes seasonally with temperature and humidity, such as with a natural material such as ethyl cellulose, use a surfactant with an amine added to a fatty acid.
You may add 0.1-0.5 wt%. In addition, when wiring is added to the substrate surface by the thin film method, the substrate surface is ground. Therefore, a sintering aid (for example, a ceramic powder for producing a green sheet) is added to the W powder in order to improve the bonding of the conductors. 1 to 3 wt% may be added. Accurately align the number of green sheets (6 to 50) required for board fabrication with the conductor wiring by the method explained so far, and perform the hot pressing method (1
After thermocompression bonding at 20 to 150 ° C. and 100 to 200 kg / cm ² ), sintering was performed at 1550 to 1650 ° C. for 1 to 2 hours in a reducing atmosphere. The substrate manufactured in this manner had good yield and mass productivity as compared with the conventional method.

Example 2 According to the method of Example 1, a mullite ceramic raw material was used as a glass ceramic raw material, and a commercially available Cu paste was used in place of the W paste to produce a glass ceramic multilayer wiring board. Good results have been obtained.

[0012]

According to the present invention, it is easy to fill the through-holes with a conductor, and it is possible to reduce the disconnection or short-circuit failure of the wiring conductor by about 75% as compared with the conventional method. Moreover, since the conductors can be filled in the through holes and the wiring can be printed at the same time, the screen plate used in the past was 78 plates, but it can be reduced to 39 plates and the manufacturing process can be reduced by 3 processes. Furthermore, compared to the conventional method, the yield can be increased from 75% to 89%, and the manufacturing cost can be reduced by 32%. Also, since the through hole diameter is small, the wiring width can be 40 to
If it is formed with μm, it is possible to manufacture a ceramic multilayer wiring board in which through holes and wiring conductors are formed in a 0.3 mm grid pattern that could not be manufactured conventionally.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a green sheet in which a through hole is filled with a conductor and a wiring conductor is formed for explaining the present invention.

FIG. 2 is a schematic cross-sectional view of a green sheet for explaining a conventional technique.

FIG. 3 is a schematic sectional view of the same green sheet.

FIG. 4 is a schematic sectional view of the same green sheet.

FIG. 5 is a schematic sectional view of the same green sheet.

FIG. 6 is a characteristic diagram illustrating the relationship between the blending ratio of the solvent (nBCA and α-terpineol) used in the paste and the breaking load of the green sheet on which the paste is printed, for explaining the present invention.

[Explanation of symbols]

1, 1 '... Green sheet, 2 ... Through hole (filled conductor paste), 3 ... Wiring conductor, 4 ... Mask (metal foil), a ... Cavity, b ... Recessed amount of paste, c ... Filling through hole Short-circuited part between the conductor and the wiring conductor.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hiroki Tozaki 1 Horiyamashita, Hadano City, Kanagawa Hitachi Ltd. Kanagawa Plant (72) Inventor Masasaku Ishihara 292 Yoshida-cho, Totsuka-ku, Yokohama, Japan Hitachi, Ltd. Production Engineering Laboratory (72) Inventor Norihiro Ami 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Stock Engineering Laboratory, Hitachi, Ltd.

Claims (1)

[Claims] 1. A step of forming a through hole having a diameter of 0.05 to 0.1 mm in a green sheet having a thickness of 0.1 to 0.2 mm using a water-soluble binder, and a release film between the green sheet and the printing stage. A method for manufacturing a ceramic multilayer wiring board, comprising the steps of inserting and filling a through hole with a conductor paste and printing a wiring at the same time, wherein a solvent containing the following raw materials is used as a solvent for the conductor paste.・ Α-Terpineol −−−−− 31
~ 100wt% ・ Diethylene glycol −−−−− 0
~ 69wt% Monobutyl ether acetate (nBCA)