JPH0918148A - Production of low temperature fired multilayer ceramic circuit board - Google Patents

Abstract

PURPOSE: To obtain a low temperature fired multilayer ceramic circuit board onto which a mark clearly distinct from the surface color of a board can be put easily. CONSTITUTION: The low temperature fired multilayer ceramic circuit board comprises inner wiring conductors 3,... and via hole conductors 4,... arranged in a laminate comprising a plurality of glass-ceramic layers and wiring conductors 2,... arranged on the surface. Marks 5 made of a material, being discolored through oxidation when the laminate 1 is fired in oxidizing atmosphere, are formed on the surface of the laminate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention integrally sinters a conductor film serving as a surface wiring conductor on a single-layered or multi-layered substrate having a conductor film serving as an inner wiring conductor sandwiched and laminated and made of a glass-ceramic material. The present invention relates to a method for manufacturing a low-temperature fired ceramic multilayer circuit board, and more particularly to formation of a positioning mark and a mark indicating a model number.

[0002]

2. Description of the Related Art For example, a low temperature fired ceramic multilayer circuit board comprises a laminated body, surface wiring conductors, mounting electronic components and the like.

A glass-ceramic consisting of glass that can be fired at a low temperature and an inorganic filler such as alumina is used as the insulating layer that constitutes this laminated body.
A via-hole conductor and an internal wiring conductor containing Ag as a main component were arranged.

Further, a surface wiring conductor containing, for example, Cu as a main component is printed and baked on the surface of the laminated body, and further various electronic components are mounted via solder or the like.

In particular, a mark for positioning recognition (hereinafter referred to as a positioning mark) is formed in a region other than the portion of the laminated body where the surface wiring conductor is formed, and when the surface wiring conductor is printed, When mounting an electronic component on a predetermined surface wiring conductor, the positioning mark is read by an image recognition device, and the surface wiring conductor is printed / baked at a predetermined position to mount the electronic component.

Such a positioning mark needs to be formed at the same time in the step of forming a laminated body. In particular,
A via-hole conductor for connecting a normal internal wiring conductor and a surface wiring conductor is formed on the outermost sheet constituting the laminate, and at the same time, a via-hole conductor exposed on the surface and acting as a positioning mark is formed in the same step. Had formed. That is, a through hole for positioning is formed in a sheet of glass-ceramic material, the through hole is filled with Ag paste containing Ag powder and glass frit, and baked at the same time as the baking process of the laminated body. .

[0007] Further, the laminated body is composed of the outermost sheet,
After forming a connection via-hole conductor for connecting a normal internal wiring and a surface wiring conductor, a pattern acting as a positioning mark exposed on the surface is formed with reference to the via-hole conductor.

[0008]

However, the positioning via-hole conductor and pattern formed as described above are
In terms of material, an Ag-based material has been used to match with the via-hole conductor for connection and the internal wiring conductor.

Since the positioning via-hole conductors and patterns of the Ag-based material become grayish white when fired in an oxidizing atmosphere, they have a low contrast with the yellow-white material which is the surface of the substrate.

In order to improve the accuracy of image recognition,
It is preferable to form the positioning mark with the via-hole conductor rather than the pattern (which causes bleeding during printing), but the glass frit oozes out on the surface of the via-hole conductor during the firing process. Is not sufficiently advanced, and the exposed surface becomes cloudy, and as a result, the color contrast between the glass-ceramic material of the laminate and the positioning mark is reduced.

Therefore, even if the image recognition device tries to recognize the positioning mark, it becomes difficult to recognize it with high reliability, and even if it is attempted to print the surface wiring conductor based on the recognition result, it is substantially impossible. This, moreover,
The same applies to the case of forming or mounting a thick film resistor film or various electronic component elements (for example, a chip resistor, a chip capacitor, an IC chip) on the surface wiring conductor.

The present invention has been devised in view of the above problems, and an object thereof is to easily form a positioning mark having a high contrast with a substrate when forming a laminated body. A method for manufacturing a low temperature fired ceramic multilayer circuit board is provided.

[0013]

SUMMARY OF THE INVENTION The present invention provides an A
A glass having a via hole conductor containing g as a main component and a conductor serving as an internal wiring conductor containing Ag as a main component formed on the surface thereof.
A low temperature in which a plurality of sheets made of a ceramic material are laminated to obtain a laminated body, and the laminated body is fired in the air or an oxidizing atmosphere, and then a surface wiring conductor film is printed / baked on the fired laminated body. In the method for manufacturing a fired ceramic multilayer circuit board, a positioning mark made of a material that is oxidized in the atmosphere for firing the laminate is provided in a region where the surface wiring conductor is not formed on the surface of the uppermost or lowermost sheet of the laminate. It is a method for manufacturing a low temperature fired ceramic multilayer circuit board, which is characterized in that it is formed.

Here, as the material to be oxidized in the firing atmosphere of the laminate, in the air or in the oxidizing atmosphere, a Cu-based material usually used for a conductor material, a tantalum silicide-based material usually used for a resistor film, and hexaboride are used. Examples include lanthanum-based materials.

[0015]

According to the present invention, in order to connect the internal wiring conductor containing Ag as a main component and the surface wiring conductor to at least the sheet located on the outermost surface among the sheets of glass-ceramic material constituting the laminate. At the same time that the via-hole conductor is formed, a mark made of a material, such as Cu, which is oxidized by firing the laminate is formed in a region where the surface wiring conductor is not formed. The sign is a pattern formed on the surface of the unbaked laminate, or a via-hole conductor (although it does not act as a conductor) exposed on the surface of the unbaked laminate.

For this reason, when a laminated body in which a plurality of sheets are laminated is fired in an oxidizing atmosphere, the conductor exposed as a marker on the surface of the unfired laminated body is oxidized and the surface thereof is It turns black.

Therefore, it is possible to form a black marker having a high contrast with white or yellowish white which is the color of the substrate material of the laminate, in a region where the surface wiring conductor is not formed.

As described above, when the high-contrast marker is used as the positioning mark, when the surface wiring conductor is printed on the surface or when various electronic parts are mounted on the surface wiring conductor formed by printing / baking. To
It can be performed easily and surely by using the image recognition device.

As a result, it is possible to easily form a sign having a high contrast with the substrate that can be recognized by the image recognition device. Accordingly, the low temperature fired ceramic multilayer circuit board can be manufactured with high reliability.

Further, by using the high-contrast sign as a display showing the model number of the component, it is possible to prevent the low-temperature fired ceramic multilayer circuit board from being misused.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a low temperature fired ceramic multilayer circuit board according to the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a low temperature fired ceramic multilayer circuit board according to the present invention, and FIG. 2 is a sectional view thereof.

In the figure, 10 is a low temperature fired ceramic multilayer circuit board, and a low temperature fired ceramic multilayer circuit board 1
0 is the laminated body 1 and the surface wiring conductor 2 formed on the surface ...
And a positioning mark (hereinafter referred to as a positioning mark) that is exposed and formed on the surface of the laminated body 1.
····, and a thick film resistor film, an insulating protective film are formed on the surface wiring conductor 2, ... And various electronic parts 6 are mounted.

The laminate 1 is composed of, for example, four glass-ceramic layers 1a to 1d, and between the layers 1a to 1d,
Internal wiring conductors 3 ... Are formed. Further, in each of the glass-ceramic layers 1a to 1d, in order to connect the internal wiring conductors 3 ... In the thickness direction, the internal wiring conductors 3 ... And the surface wiring conductors 2 are connected. Via hole conductors 4 are formed.

Further, as shown in FIG. 2, on the surface of the laminated body 1, in the region where the surface wiring conductors 2 ... Are not formed, for example, at the end of the laminated body 1, the positioning mark 5 is formed on the surface. ... are formed.

The positioning marks 5 ...
Although it is formed on both front and back main surfaces, it may be formed on only one main surface.

Further, in the drawing, at least the exposed portion of the via-hole conductor which penetrates at least the glass-ceramic layers 1a and 1d in the thickness direction is used as the positioning mark 5, but the pattern may have a predetermined shape. .

In the following, the following manufacturing method will be described by taking an example in which the positioning mark 5 is formed on the exposed portion of the via-hole conductor.

First, the glass-ceramic layer 1 of the laminated body 1
A glass-ceramic green sheet to be a to 1d is formed. For example, the green sheet is, for example, SiO ₂ −.
Glass powder such as Al ₂ O ₃ —B ₂ O ₃ —CaO—PbO, inorganic filler such as alumina ceramic powder, organic binder such as alkyl methacrylate, plasticizer such as DBP, and organic solvent such as toluene. And are mixed and kneaded with a ball mill to form a slurry. Here, the mixing ratio of the ceramic powder and the glass powder that becomes the crystallized glass is 30 wt% of the ceramic powder.
% And 70% by weight of glass powder. This slurry is tape-molded by a doctor blade method or the like and cut into a predetermined size to form a green sheet.

Next, through holes are punched or the like at the positions of the via-hole conductors 4 ... Which connect the internal wiring conductors 3 to the green sheets to be the glass-ceramic layers 1b to 1c. Then, the through holes are printed and filled with Ag-based conductive paste containing Ag as a main component,
Further, a conductor film to be the internal wiring conductors 3 ... Is printed on the surface using Ag-based conductive paste and dried to form.

Next, through holes are formed at the positions of the via-hole conductors 4 ... Which connect the internal wiring conductors 3 ... And the surface wiring conductors 2 ... to the green sheets to be the glass-ceramic layers 1a, 1d. In addition, the surface wiring conductor 2 of the laminated body 1 ...
In the region where the mark is not formed, a through hole which serves as a positioning via hole conductor which is the positioning mark 5 is formed by punching or the like. And the via-hole conductor 4 for connection
The Ag-based conductive paste is printed and filled in the through-holes to be ... And the oxidation reaction occurs when the through-holes to be the positioning marks 5 are fired in the air or an oxidizing atmosphere. Printing and filling are performed using a material that changes color, for example, a Cu-based conductive paste whose main component is Cu,
Dry it. The internal wiring conductors 3 ... And a conductor film are formed on the green sheet which becomes the glass-ceramic layer 1d.

Here, the Ag-based conductive paste is, for example, a predetermined amount of low-resistance metal powder such as Ag powder or Ag alloy (Ag-Pd) powder, and if necessary, for example, a predetermined amount of borosilicate-based low melting point powder. Glass, and optionally SiO, for example
₂ , a metal oxide such as Bi ₂ O ₃ , an organic binder such as ethyl cellulose, and an organic solvent such as 2.4-trimethyl-1.3-pentadiol monoisobutyrate are mixed and homogeneously mixed. Things are used.

The Cu-based conductive paste is a predetermined amount of Cu-based metal powder, a predetermined amount of, for example, a borosilicate low-melting glass, and, if necessary, Si, for example.
A metal oxide such as O ₂ or Bi ₂ O ₃ , an organic binder such as ethyl cellulose, and an organic solvent such as 2.4-trimethyl-1.3-pentadiol monoisobutyrate are mixed to obtain a homogeneous mixture. What is done is used.

The green sheets thus obtained are aligned based on the conductors to be the via-hole conductors 4, ..., Laminated according to the laminating order, thermocompression-bonded, and laminated in an unfired state. Form the body.

Next, the unfired laminate 1 is integrally fired in the air or an oxidizing atmosphere. Specifically, in an oxygen atmosphere or an air atmosphere, a peak temperature of 900
The temperature is raised to about ℃ and fired, but it is 500 ℃ during the heating process.
The organic components contained in the laminate are removed before and after the sintering reaction is performed up to 900 ° C.

As a result, the glass-ceramic layer 1a,
Positioning mark 5 formed on the 1d green sheet
The via-hole conductor that becomes ... Is also fired.
Since the material of the via-hole conductor for positioning is a Cu-based material, the exposed portion of the via-hole conductor exposed on the surface of the laminated body 1 is oxidized by firing in the air or an oxidizing atmosphere, and is changed to black. I will end up. That is, by this, the black positioning marks 5 ... Of the exposed shape of the via-hole conductor are formed.

Next, a conductive paste made of Cu-based material or Ag-based material is printed and baked on the surface of the laminated body 1 so as to be connected to the connecting via-hole conductors 4 ... The wiring conductors 2 are formed.

In the printing of this conductive paste, a printing device capable of position correction by automatic image recognition is used, and positioning marks 5, ...
・ Recognize and print based on this. Therefore,
Even when firing shrinkage, which is difficult to control, occurs in firing the laminate 1, the surface wiring conductors 2 ... Which are completely connected to the via hole conductors 4 ... For connection can be formed.

Here, the materials of the surface wiring conductors 2 ... Will be described in detail. Particularly, as the material, Ag, Cu, etc. can be enumerated. However, if the surface wiring conductors 2 ... Cu based materials are preferred. At this time, the firing temperature for firing the Cu-based conductive paste is 8 in order to suppress the eutectic reaction with Ag (via-hole conductor for connection).
It is important to fire at 70 ° C. or lower, and moreover, it is important to carry out in a reducing atmosphere such as a nitrogen atmosphere or a neutral atmosphere in order to prevent oxidation of the surface wiring conductors 2 ...

When an Ag-based material is used as the surface wiring conductors 2, ..., Especially, the surface wiring conductors 2 ...
• Even if Ag migration occurs between the lines, it is necessary to control the distance between the lines so that sufficient insulation characteristics can be maintained. When this Ag-based material is used, the firing atmosphere can be baked in an oxidizing atmosphere or an air atmosphere. After that, when forming a thick-film resistor film, a ruthenium oxide-based material that is more reliable than a conventional thick-film resistor film is used. It will be possible to use materials.

After forming such surface wiring conductors 2, ..., If necessary, a thick film resistor film and various protective films are formed, and further various electronic components 6, such as chip resistors and chip capacitors. , IC chips, etc. are mounted. Also during this mounting, various electronic components 5 can be mounted at predetermined positions while reading the above-described black positioning marks 5 ... Using the automatic mounting device and the image recognition device.

In the above manufacturing method, the laminate 1 is formed by firing in the air or an oxidizing atmosphere. By this firing, the conductor or pattern serving as a positioning mark exposed on the surface of the laminate 1 is exposed to the atmosphere or Since it is made of a material that is oxidized by firing in an oxidizing atmosphere, its surface is oxidized and the quality thereof changes to black. Therefore, the contrast ratio is improved between the surface color of the laminate 1 and the yellowish white color or the white color, and the reading reliability by the image recognition device is greatly improved.

From this, as described above, the surface wiring conductor 2
When printing / baking ..., printing / baking other members, and mounting various electronic parts 6, the printing position is read while recognizing and recognizing the positioning marks 5 ... Can be very easily corrected to a proper position, and a low temperature fired ceramic multilayer circuit board having high connection reliability can be manufactured.

In the above embodiment, the positioning marks 5 ...
Is formed by the via-hole conductor formed in the glass-ceramic layers 1a and 1d located on the outermost surface of the laminated body 1 at least. This positioning mark 5 ...
May be simply a film having a pattern of a predetermined shape on the green sheet to be the glass-ceramic layers 1a and 1d. In the case of the positioning mark 5 by the via-hole conductor and the positioning mark 5 by the pattern film, for example, in the case of a pattern film, printing sag or the like occurs when a paste made of a material that can be fired in a reducing atmosphere is printed. Therefore, it is preferable to form the via hole conductor because the positioning mark 5 with high accuracy may not be obtained.

In the above embodiment, the positioning marks 5 ...
・ As a material that can be fired in a reducing atmosphere,
Although Cu-based materials are used, tantalum silicide-based materials and lanthanum hexaboride-based materials may be used instead. This tantalum silicide material and lanthanum hexaboride material are usually
It is a resistor material compatible with a reducing atmosphere when forming a thick film resistor film formed on a Cu-based surface wiring conductor.

The positioning mark 5 may be formed only on one main surface of the laminated body 1.

Further, as the mark, the positioning mark 5 which is read mainly for correcting the position by the image recognition device has been described, but the model number of the multilayer circuit board (numerals, alphabet, etc.)
It may be a sign for displaying. in this case,
Since the model number of the multilayer circuit board can be specified, it is possible to completely prevent misuse of the multilayer circuit board.

It should be noted that in the above-mentioned embodiment, there is no description about extracting a plurality of multilayer circuit boards on the green sheet, but for example, a plurality of regions can be extracted so that the green sheet can be extracted by a plurality of circuit boards. , A conductor film to be the via-hole conductors 4 ..., Internal wiring conductors 3 ... Is formed in each region, and dividing grooves are formed in the unfired laminated body, and the final step of the manufacturing process is performed. It does not matter if it is divided by. In this case, the positioning mark may be formed in each area, or may be formed in a portion to be discarded by division.

[0048]

As described above, according to the present invention, it is formed when the laminate is fired in the air or an oxidizing atmosphere.
At the same time, a mark made of a material that is oxidized in this firing atmosphere is formed. Therefore, the surface of the positioning mark is oxidized and discolored, and the contrast with the color of the surface of the substrate becomes clear.

Therefore, the reading reliability in the image recognition is improved, and it is possible to print or mount the surface wiring conductors or the electronic parts at predetermined positions respectively, and the connection reliability is improved. It becomes a low temperature fired ceramic multilayer circuit board.

[Brief description of the drawings]

FIG. 1 is a plan view of a low temperature fired ceramic multilayer circuit board according to the present invention.

FIG. 2 is a cross-sectional view of a low temperature fired ceramic multilayer circuit board according to the present invention.

[Explanation of symbols]

 10 ... Low temperature fired ceramic multilayer circuit board 1 ... Laminated body 1a to 1d ... Glass-ceramic layer 2 ... Surface wiring conductor 3 ... Internal wiring conductor 4 ... Via hole conductor 5 ... Signs 6 ... Electronic components

Claims (1)

[Claims] 1. A plurality of sheets made of a glass-ceramic material having a via-hole conductor containing Ag as a main component and a conductor serving as an internal wiring conductor containing Ag as a main component formed on a surface of the through-hole, are laminated. In the method for producing a low-temperature fired ceramic multilayer circuit board, the body is obtained, the laminate is fired in the atmosphere or an oxidizing atmosphere, and then a surface wiring conductor film is printed / baked on the fired laminate. A low-temperature fired ceramic, characterized in that a sign made of a material that is oxidized in the atmosphere for firing the laminate is formed in a region where the surface wiring conductor is not formed on the surface of the uppermost or lowermost sheet of the laminate. Manufacturing method of multilayer circuit board.