JP2715911B2 - Multilayer wiring ceramic substrate and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring ceramic substrate and a method of manufacturing the same, and more particularly to wiring printing on a green sheet constituting the multilayer wiring ceramic substrate.

[0002]

2. Description of the Related Art Conventionally, the production of a multilayer wiring ceramic substrate by a green sheet method is performed by a process as shown in FIG. First, an organic solvent c such as a dispersant and a plasticizer is added to a mixed powder of alumina a powder and a binder b for solidification.
And mixing, and sufficiently stirred to form a slurry.

Here, as the binder b, cellulose type (methyl cellulose and ethyl cellulose), polyvinyl alcohol, acrylic type, polyvinyl butyral and the like are mainly used. As a dispersant, a nonionic surfactant is used, and as a plasticizer, dibutyl phthalate, dioctyl phthalate, glycerin, or the like is used.

[0004] There are several methods for producing ceramic green sheets. Here, the doctor blade method suitable for forming thin sheets is used. The doctor blade method is a method in which the slurry is cast by a gap between a knife called a doctor blade and a continuous film and dried to form a green sheet on the film.

In this method, the thickness of the green sheet can be set to about 0.03 to 1 mm. In this example, the width is about 0.2 mm and the casting width is about 160 mm.
mm. This continuous sheet is cut into a size of about 150 mm square to obtain a square green sheet (step S11 in FIG. 6).

Next, through holes are formed in the sheet at predetermined positions determined by a combination of pins and dies (step S12 in FIG. 6). The diameter of the through hole is about 250 μm, and the pitch of the holes is about 2 mm.
Nu

After the formation of the through holes, the conductive paste is embedded in all the through holes from the surface of the green sheet by the thick film printing method (step S13 in FIG. 6). Thereafter, a wiring pattern is formed on the surface of the green sheet to connect predetermined through holes (step S1 in FIG. 6).
4).

In consideration of the firing temperature of ceramics, tungsten (W) or molybdenum (M) having a high melting point is used as a printing paste material for embedding through holes and forming wiring.
o) is used. In this case, the wiring width and the film thickness of the signal wiring are designed to be 200 μm and 10 μm after firing, respectively.

As described above, the ceramic green sheets on which the wiring patterns are printed are laminated in a laminating step in a predetermined order so as not to be displaced (step S15 in FIG. 6). Formation (Step S16 in FIG. 6) to form a green laminate.

The green laminate is subjected to binder removal firing at about 1500 ° C. (step S17 in FIG. 6), and is further shaped by grinding (step S18 in FIG. 6) to form a multilayer wiring ceramic substrate (FIG. 6). Step S19).

When a multilayer wiring ceramic substrate is manufactured by the above process, the embedding of the conductive paste into the through holes of the green sheet is usually performed by thick film printing using one type of screen.

[0012]

In the above-described conventional method for manufacturing a multilayer wiring ceramic substrate, the embedding of the conductive paste into the through-hole is performed by thick film printing using one type of screen. It is necessary to fill a sufficient amount of the conductive paste to ensure conduction reliability when the conductive paste is embedded in the conductive paste.

In the above thick film printing method, when the ratio of the thickness of the sheet to the diameter of the through-hole, that is, the aspect ratio is generally increased due to the high density of the wiring, it becomes difficult to fill the through-hole with a sufficient amount of conductive paste. .

In recent years, the diameter of a through-hole has become finer as the wiring density has increased, and the aspect ratio tends to increase.

In the above-described manufacturing process of the multilayer wiring ceramic substrate, when the conductive paste is filled into the through holes by thick film printing, as shown in FIG. Even when a sufficient amount of the conductive paste 10b is not filled and the green laminate 8 is laminated on another green sheet 8 to form the green laminate 11, conduction between the through hole 10a and the wiring pattern 8a may not be obtained.

For this reason, disconnection is prevented by repeating printing twice or more. However, in this repetitive printing, the conductor paste adheres to the periphery of the through-hole, causing blurring and bleeding, and a short circuit with an adjacent conductor pattern is likely to occur.

Therefore, an object of the present invention is to solve the above-mentioned problems, and to embed a sufficient amount of conductive paste in a through-hole without repeating printing from the same surface, thereby improving the conduction reliability of the through-hole. It is an object of the present invention to provide a multilayer wiring ceramic substrate and a method for manufacturing the same, which can improve the performance.

[0018]

A multilayer wiring ceramic substrate according to the present invention is a multilayer wiring ceramic substrate comprising a green sheet having through holes, wherein a first wiring pattern is formed on the surface of the green sheet by the pattern of the through holes. And a second screen formed with the pattern of the through holes on the back surface of the green sheet, the conductive paste is filled from both sides of the green sheet , and the second screen is
The first screen is centered on any axis on the plane
It is formed by rotating by 180 ° .

The method for manufacturing a multilayer wiring ceramic substrate according to the present invention includes the step of filling a conductive paste by a thick film printing method using a screen in a through hole of a green sheet of the multilayer wiring ceramic substrate. A first step of filling a conductive pattern from the surface of the green sheet to the through hole using a first screen formed with the pattern of the through hole on the surface of the green sheet; And a second step of filling the through hole with a conductor pattern from the back surface of the green sheet using a second screen formed with the pattern of the through hole in the second step .
The step is to move the first screen to any one of its
The second disk formed by being rotated by 180 ° about the opposite axis.
Using lean, rotate around the arbitrary direction axis
From the back surface of the obtained green sheet to the through hole
The conductor pattern is filled .

[0020]

In the step of embedding the conductor paste in the through holes of the green sheet, the conductor paste is embedded in all the through holes from the surface of the green sheet using a screen having a normal pattern.

Next, a conductor paste is embedded in all the through holes from the back surface of the green sheet using a reversing screen formed by rotating the normal pattern by 180 ° about an arbitrary direction axis on the plane.

Thus, even when the aspect ratio is large, it is possible to embed a sufficient amount of conductive paste in the through-hole without repeatedly printing from the same surface, thereby improving the conduction reliability of the through-hole. .

[0023]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a view showing a manufacturing process of a multilayer wiring ceramic substrate according to one embodiment of the present invention. Referring to the drawing, in one embodiment of the present invention, a multilayer wiring ceramic substrate is manufactured in the same process as the conventional example shown in FIG. 6 except that a process of embedding a conductive paste into a through hole is different.

Here, in FIG. 1 and FIG.
1 to step S11, step S2 to step S12, step S5
Corresponds to step S14, step S6 corresponds to step S15, step S7 corresponds to step S16, step S8 corresponds to step S17, step S9 corresponds to step S18, and step S10 corresponds to step S19.

After the through holes are formed in the green sheet, a conductive paste is embedded in all of the through holes by a thick film printing method. In this step, if the ratio between the thickness of the sheet and the diameter of the through hole, that is, the aspect ratio is increased, it becomes difficult to embed a sufficient amount of the conductive paste. A normal thick film printing method varies depending on various conditions, but when the aspect ratio is 2 or more, it is particularly difficult to embed a sufficient amount of paste.

In one embodiment of the present invention, in the step of embedding the conductor paste into the through holes, first, a conductor paste is embedded from the surface of the green sheet into all the through holes using a screen having a normal pattern ( Step S3 in FIG. 1).

Next, all the through-holes are formed from the back surface of the green sheet using a reversing screen in which the normal pattern is reversed left and right, that is, a screen formed by rotating the normal pattern by 180 ° about an arbitrary axis on the plane. The conductive paste is embedded therein (step S4 in FIG. 1). As a result, a sufficient amount of paste can be embedded in through holes having an aspect ratio of 4 to 5.

FIG. 2 is a view showing an example of embedding a conductive paste into a through hole from the surface of a green sheet according to one embodiment of the present invention, and FIGS. 3 and 4 are green sheets according to one embodiment of the present invention. FIG. 6 is a diagram showing an example of embedding a conductor paste into a through hole from the back surface of FIG.

FIG. 3 shows a conductive paste (not shown) from the back surface of the green sheet (not shown) to all the through holes by using a reversing screen 5 formed by rotating the screen 1 of FIG. 2 by 180 ° about the Y axis. Zu) is shown.

FIG. 4 shows a state in which the conductive paste is embedded in all the through holes from the back surface of the green sheet using the reversing screen 6 formed by rotating the screen 1 of FIG. 2 by 180 ° about the X axis. I have.

When the conductor paste is embedded from the back of the green sheet using the reversing screens 5 and 6, when holding the green sheet in the metal frame 4 with the back of the green sheet facing upward, the green sheet is held. By rotating the screen 1 by 180 ° about the rotation axis (for example, X axis or Y axis) of the screen 1 at the time of formation, the positions of the through holes on the back surface of the green sheet and the reversing screens 5, 6
And the hole for embedding the through hole. Also, 3 on the screen 1 and the reversing screens 5 and 6 indicate orientation marks indicating a reference at the time of printing.

FIG. 5 is a view showing the filling of the conductive paste into the through holes of the green sheet according to one embodiment of the present invention. In the figure, a through hole 7 of a green sheet 7 is shown.
For a, the conductor paste 7b is filled from the front surface and the conductor paste 7c is filled from the back surface.

Therefore, since a sufficient amount of the conductive paste 7b, 7c is filled in the through hole 7a of the green sheet 7, the through hole 7a is formed when the green laminate 9 is laminated on another green sheet 8. Conduction between the wiring pattern 7a and the wiring pattern 8a can be established.

As described above, the conductive paste 7b is filled from the front surface of the green sheet 7 having the through holes 7a using the screen 1 and the conductive paste 7c is used from the back surface of the green sheet 7 using the reversing screens 5 and 6.
By filling the through hole, a sufficient amount of conductive paste can be embedded in the through hole without repeating printing from the same surface on the green sheet with the through hole with a large aspect ratio, improving the conduction reliability of the through hole. Can be improved.

[0036]

As described above, according to the present invention, in a multilayer wiring ceramic substrate including a green sheet having through-holes, a first screen formed in a pattern of through-holes on the surface of the green sheet and a back surface of the green sheet. By filling the conductive paste from both sides of the green sheet with the second screen formed in the pattern of the through hole in the above, a sufficient amount of the conductive paste is embedded in the through hole without performing repetitive printing from the same surface. Thus, there is an effect that conduction reliability of the through hole can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a manufacturing process of a multilayer wiring ceramic substrate according to one embodiment of the present invention.

FIG. 2 is a view showing an example of embedding a conductive paste into a through hole from the surface of a green sheet according to one embodiment of the present invention.

FIG. 3 is a diagram showing an example of embedding a conductive paste into a through hole from the back surface of a green sheet according to one embodiment of the present invention.

FIG. 4 is a diagram showing an example of embedding a conductive paste into a through hole from the back surface of a green sheet according to one embodiment of the present invention.

FIG. 5 is a view showing filling of a conductive paste into through holes of a green sheet according to one embodiment of the present invention.

FIG. 6 is a view showing a manufacturing process of a conventional multilayer wiring ceramic substrate.

FIG. 7 is a diagram showing filling of a through-hole of a green sheet with a conductive paste according to a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 screen 2 through hole embedding hole 4 metal frame 5, 6 reversing screen 7, 8 green sheet 7 a through hole 7 a, 7 c conductive paste 8 a wiring pattern

Claims (2)

(57) [Claims] 1. A multilayer wiring ceramic substrate comprising a green sheet having a through hole, wherein a first screen formed by the pattern of the through hole on the surface of the green sheet and the pattern of the through hole on the back surface of the green sheet. The green paste is filled with conductive paste from both sides of the green sheet by the second screen formed by the second screen .
One screen is centered on an arbitrary axis on the plane.
A multilayer wiring ceramic substrate formed by being rotated by 80 ° . 2. A green sheet of a multilayer wiring ceramic substrate.
Using a thick film printing method with a screen in the through hole of
Multilayer wiring ceramic including filling process to fill body paste
A method of manufacturing a substrate, comprising:
The first formed by the pattern of the through hole in the first
Using a screen from the green sheet surface,
A first step of filling the through hole with a conductor pattern;
The pattern of the through hole on the back of the green sheet
Using a second screen formed of green
Fill the through hole with a conductor pattern from the back of the
Forming the filling step from the second step of filling;
In the second step, the first screen is optionally moved on its plane.
The second axis formed by rotating by 180 ° about the directional axis of
Using a screen, rotate about the arbitrary direction axis.
From the back of the green sheet
Is filled with a conductor pattern.
Manufacturing method of a multilayer wiring ceramic substrate.