JPH1154918A - Thick-film multilayered circuit board and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an alignment mark from becoming blurred by reducing the level difference between the printed surface of a thick layer and the printed surface of the alignment mark by forming the alignment mark on a raised layer which is raised from one surface of a substrate in the thickness direction of the substrate. SOLUTION: A raised layer 20 is formed on the part of one surface of a ceramic substrate 12 where no multilayered thick-film circuit is formed and an alignment mark 22 is formed on the layer 20. The layer 20 is simultaneously formed with an insulating layer 16 by using the same material as that of the layer 16 and the mark 22 is simultaneously formed with a second conductor 18 by using the same material as that of the conductor 18 by screen printing. Consequently, the level difference between the printed surface of a thick layer on which screen printing is performed simultaneously with the mark 22 and the printed surface of the mark 22 becomes smaller and the mark 22 is prevented from becoming blurred. Therefore, the yield of a thick-film multilayered circuit board 10 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for preventing a thin film circuit having a multilayer structure and an alignment mark on a substrate from being blurred when the alignment mark is printed.

[0002]

2. Description of the Related Art A thick film multilayer circuit board having a multilayer structure in which a plurality of types of thick film patterns are sequentially laminated by performing screen printing a plurality of times on one surface of a substrate is used for an automatic component mounting machine. It is required that an alignment mark for recognizing a reference position of a substrate is provided on a portion of one surface of the substrate where the thick film circuit is not formed. While the alignment mark serves as a reference point for mounting electronic circuit components such as a chip-shaped semiconductor component, a chip-shaped capacitor, a chip-shaped resistor, and a chip-shaped coil on a substrate, the alignment mark is Since the component mounting pad for mounting and connecting is generally provided on a part of the uppermost layer conductor of the multilayer film thick film circuit, the component mounting pad and the alignment mark are provided. In order to improve the positional accuracy during the alignment, it is preferable that the alignment mark is patterned on the same mask or a part of the plate making as the pattern of the uppermost conductor, and is simultaneously formed by screen printing for printing the uppermost conductor. It is.

[0003]

By the way, conventionally,
By screen printing for printing the uppermost layer conductor, the conductor thick film material of the alignment mark pattern was directly applied to a portion of the one surface of the substrate where the thick film circuit was not formed. However, while the uppermost conductor is laminated on the lower conductor or insulating layer that has already been printed, the alignment mark is printed directly on the substrate. Since the height difference from the printing surface occurs, there is an inconvenience that the contact of the plate making surface with the printing surface becomes insufficient near the alignment mark, and the alignment mark is blurred.
Such blurring of the alignment mark makes the recognition of the component mounting reference position of the automatic component mounting machine unstable, and thus has been one of the causes of reducing the yield of the substrate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thick-film multilayer printed board free from blurring of alignment marks and a method of manufacturing the same.

[0005]

A first aspect of the present invention for achieving the above object is to provide a substrate, comprising:
A thick film circuit having a multilayer structure in which a plurality of types of thick film patterns are sequentially laminated by performing screen printing a plurality of times on one surface of the substrate, and a portion of the one surface of the substrate where the thick film circuit is not formed. A thick film multi-layer circuit board, comprising: an alignment mark that is simultaneously thick-film printed by any one of a plurality of screen printings, wherein the alignment mark is raised in a thickness direction from one surface of the substrate. It is formed on a layer.

[0006]

According to the first aspect of the present invention, since the alignment mark of the thick-film multilayer circuit board is formed on the raised layer which is raised in the thickness direction from one surface of the substrate, the alignment mark and the alignment mark are formed. At the same time, the difference in height between the printing surface of the thick film layer to be screen-printed and the printing surface of the alignment mark is reduced, and the occurrence of blurring of the alignment mark is suitably prevented.

[0007]

The gist of the method for suitably manufacturing the thick film multilayer circuit board according to the first aspect of the present invention is that a board and screen printing are performed on one surface of the board. A thick film circuit having a multilayer structure in which a plurality of types of thick film patterns are sequentially stacked by performing a plurality of times, and any one of the plurality of times in a portion of the surface of the substrate where the thick film circuit is not formed. A method for manufacturing a thick-film multilayer circuit board including an alignment mark that is simultaneously printed with a thick film by screen printing, comprising a step of forming a raised layer located below the alignment mark.

[0008]

According to the second aspect of the present invention, the step of forming the raised layer located below the alignment mark allows
Since the height of the printing surface of the alignment mark is raised above the substrate surface, the difference in height between the printing surface of the thick film layer to be screen-printed simultaneously with the alignment mark and the printing surface of the alignment mark is reduced, The occurrence of blurring of the alignment mark is suitably prevented.

[0009]

Another aspect of the present invention is preferably such that in the first invention, the raised layer is formed simultaneously with at least one of the thick film layers constituting the thick film circuit having the multilayer structure. is there. In this case, there is no need to additionally provide an operation only for forming the raised layer, and it is constituted by an operation for forming at least one of the thick film layers constituting the thick film circuit having the multilayer structure up to that time. Therefore, there is an advantage that the process is not complicated.

Preferably, the first invention and the second invention
In the invention, the alignment mark is formed of a plurality of thick film layers by performing screen printing for forming the thick film circuit having the multilayer structure a plurality of times, and at least one of the plurality of thick film layers is used. An uppermost layer is formed in a pattern showing the alignment mark. In this case, since the alignment marks are formed by screen printing for forming the thick film multilayer circuit board, there is an advantage that the process is not complicated.

Preferably, in the second invention,
The step of forming the raised layer located below the alignment mark is a step of simultaneously forming at least one of the thick film layers forming the thick film circuit having the multilayer structure. In this case, it is not necessary to further provide a step only for forming the raised layer, and the alignment mark is formed simultaneously with at least one of the thick film layers forming the thick film circuit having the multilayer structure up to that time. Therefore, there is an advantage that the process is not complicated.

Preferably, the first invention and the second invention
In the invention, the thick film circuit having the multilayer structure includes an uppermost layer conductor, a lower layer conductor formed below the uppermost layer conductor, and a lower layer conductor interposed between the uppermost layer conductor and the lower layer conductor. The semiconductor device has an insulating layer that insulates the upper conductor and the lower conductor in the thickness direction, and the alignment mark is formed on the insulating layer. With this configuration, the insulating layer of the lower-layer conductor, the insulating layer, and the uppermost-layer conductor constituting the multi-layer thick film circuit has a sufficiently large thickness as compared with the lower-layer conductor and the uppermost-layer conductor to withstand the withstand voltage. Since the alignment marks are formed so as to maintain the performance, the alignment marks are formed on the raised layer having the same thickness as the insulating layer, so that the alignment marks are screen-printed simultaneously with the uppermost layer conductor, for example. Since the difference between the height of the printing surface of the alignment mark and the height of the printing surface of the uppermost conductor at that time is suitably reduced, there is an advantage that the blurring of the alignment mark is further prevented.

[0013]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

In FIG. 1, a thick-film multilayer circuit board 10 comprises:
A plurality of types of thick film materials are sequentially printed in multiple layers by screen printing a plurality of times and fired on a ceramic substrate 12 made of alumina, forsterite, steatite, glass, or the like. . In practice, many thick-film circuits are often formed simultaneously on a common ceramic substrate on which break grooves are formed so as to be dividable, but FIG. 1 shows a cross section of one thick-film circuit. Is schematically shown.

On one surface of the ceramic substrate 12, a first conductor 14, which is made of a conductive thick film material and has a predetermined circuit pattern, is made of an insulating thick film material and has a sufficient withstand voltage performance. 4 of the first conductor 14
An insulating layer 16 having a thickness of about 6 to 6 times and a second conductor 18 made of a conductive thick film material and having a predetermined circuit pattern are sequentially laminated to form a multi-layer thick film circuit. A raised layer 20 is formed on a portion of one surface of the ceramic substrate 12 where the multilayer thick film circuit is not formed, for example, a blank portion, and an alignment mark 22 is formed on the raised layer 20. . The raised layer 20 is formed by screen printing at the same time as the insulating layer 16 using the same material as the insulating layer 16, and the alignment mark 22 is formed by screen printing at the same time as the second conductor 18 using the same material as the second conductor 18. Have been.

The alignment mark 22 is formed by attaching an electronic circuit component 24 such as a chip-like semiconductor component such as a chip-like IC, a chip-like transistor or a chip-like diode, a chip-like capacitor, a chip-like resistor or a chip-like coil to a
It serves as a reference point for a position for automatic mounting at a predetermined mounting position provided on a part of the upper second conductor 18, and is optically recognized by an automatic component mounting machine (not shown). is there. In addition, the alignment mark 22
Are represented, for example, by a small circle pattern, a square pattern, a cross pattern, or the like, and are provided at least at two corners of the ceramic substrate 12 which are substantially diagonally located.

The thick-film multilayer circuit board 10 configured as described above is manufactured, for example, by performing the steps shown in FIG. In FIG. 2, in the lower conductor printing step 30, a metal powder that functions as a conductor such as silver, silver-palladium, silver-platinum, or copper, a glass frit that functions as a binder, and a resin for forming a paste having a predetermined viscosity. The ceramic substrate 1 is screen-printed using a paste-like conductive thick film material in which
The first conductor 14 having a predetermined circuit pattern is formed on one surface of the second conductor 2, and in a lower conductor firing step 32, the first conductor 14 is fired at a temperature at which the metal powder is sintered. Thereby, the first conductor 14 of, for example, about 10 μm is fixed to the ceramic substrate 12.

Next, in an insulating layer printing step 34, a ceramic powder functioning as a filler such as alumina, zircon, and Celsian, a glass frit functioning as a binder,
Screen printing is performed using a paste-like insulating thick film material in which a resin and a solvent for mixing into a paste having a predetermined viscosity are mixed, so that an insulating layer 16 is formed on the first conductor 14. In an insulating layer firing step 36, the insulating layer 16 is fired at a temperature at which the glass frit is melted. Thus, the insulating layer 16 having a thickness of, for example, about 50 μm is fixed on the ceramic substrate 12. If the thickness of the insulating layer 16 cannot be obtained by one screen printing, the insulating layer printing step 34 and the insulating layer baking step 36 are repeatedly performed a plurality of times. At this time, in the plate making for printing the insulating layer 16, not only the pattern of the insulating layer 16 but also the pattern for printing the raised layer 20 located below the alignment mark 22 are formed. The raised layer 20 is printed at the same time as the insulating layer 16 in the insulating layer printing step 34, and is fired at the same time as the insulating layer 16 in the insulating layer firing step 36. Therefore, the insulating layer printing step 34 or the additional insulating layer firing step 3
6 also functions as a step of forming the raised layer 20 located below the alignment mark 22.

In the uppermost conductor printing step 38,
Silver, silver-palladium, silver-platinum, metal powder functioning as a conductor such as copper, glass frit functioning as a binder,
A second conductor having a predetermined circuit pattern on the insulating layer 16 by performing screen printing using a paste-like conductive thick film material in which a resin and a solvent for mixing into a paste having a predetermined viscosity are mixed. The second conductor 18 is fired at a temperature at which the metal powder is sintered in the uppermost conductor firing step 40. Thereby, the second conductor 18 of, for example, about 10 μm is fixed on the insulating layer 16. At this time, in the plate making for printing the second conductor 18, not only the pattern of the insulating layer 16 but also the pattern representing the alignment mark 22 is formed. In the step 38, printing is performed simultaneously with the second conductor 18, and in the above-described uppermost layer conductor firing step 40, the printing is performed simultaneously with the second conductor 18.

As described above, according to the thick film multilayer circuit board 10 of the present embodiment, the alignment mark 22 is formed by the raised layer formed simultaneously with at least one of the thick film layers constituting the thick film circuit having the multilayer structure. 20, the difference between the height of the printing surface of the thick film layer to be screen-printed simultaneously with the alignment mark 22 and the height of the printing surface of the alignment mark 22 is reduced. Is suitably prevented. Therefore,
The yield of the thick film multilayer circuit board 10 is improved.

According to the manufacturing process of this embodiment, the raised layer 20 located below the alignment mark 22 is
The step of simultaneously forming at least one of the thick film layers constituting the thick film circuit having the multilayer structure (the insulating layer printing step 34 and the insulating layer printing baking step 36) reduces the height of the printing surface of the alignment mark 22 to the substrate surface. The printing surface of the thick film layer to be screen-printed simultaneously with the alignment mark 22 and the alignment mark 22
And the difference in height from the printing surface is reduced, and the occurrence of blurring of the alignment mark 22 is suitably prevented.

In this embodiment, the thick film multilayer circuit board 1
0, the thick film circuit having a multi-layer structure has a top conductor (second conductor 1).
8), a lower conductor (first conductor 14) formed below the uppermost conductor, and the uppermost conductor and the lower conductor interposed between the uppermost conductor and the lower conductor. It has an insulating layer 16 that insulates in the thickness direction,
The alignment mark 22 is formed on the insulating layer 16. In particular, in the thick-film multilayer circuit board 10 of the present embodiment, the first conductors 1 forming the thick-film circuit having the multilayer structure are formed.
4, the insulating layer 16 of the insulating layer 16 and the second conductor 18
Since the alignment mark 22 is formed to be sufficiently thicker than the first conductor 14 and the second conductor 18 and to maintain a pressure resistance of about several thousands volts,
By forming the alignment mark 22 on the raised layer 20 having the same thickness as the conductor 18, the alignment mark 22 is formed on the second conductor 18.
At the same time, the difference between the height of the printing surface of the alignment mark 22 and the height of the printing surface of the second conductor 18 during screen printing is preferably reduced, so that the blurring of the alignment mark 22 is further prevented. There are advantages.

Incidentally, the second conductor 18 is screen-printed on the insulating layer 16 by using the same plate making because the raised layer 20 is not provided below the alignment mark 22, and at the same time, the alignment mark 22 is formed on the ceramic substrate. 12 is screen printed directly on its second conductor 18.
The height difference between the printing surface of the alignment mark 22 and the printing surface of the alignment mark 22 becomes large, and the contact of the plate making near the alignment mark 22 with the ceramic substrate 12 becomes insufficient. For example, as shown in FIG.
2 has been printed in a blurred state.

Although the embodiment of the present invention has been described with reference to the drawings, the present invention can be applied to other embodiments.

For example, in the thick-film multilayer circuit board 10 of the above-described embodiment, the raised layer 20 for raising the printing surface of the alignment mark 22 is printed at the same time as the screen printing for printing the insulating layer 16 so as to be insulated. Layer 1
6, but may be formed by laminating a layer formed simultaneously with the screen printing for printing the first conductor 14 and a layer printed simultaneously with the screen printing for printing the insulating layer 16. No problem. By doing so, the difference in height between the printing surface of the alignment mark 22 and the printing surface of the second conductor 18 when the alignment mark 22 is screen-printed simultaneously with the second conductor 18 is further reduced. There are advantages.

In the above-described embodiment, the thick-film circuit having a multilayer structure of the thick-film multilayer circuit board 10 includes two layers of the first conductor 14 and the second conductor 18 insulated in the thickness direction by the insulating layer 16. However, it may be composed of three or more conductor layers.

Further, the thick-film multilayer circuit board 1 of the above-described embodiment
In FIG. 0, the thick film circuit having a multilayer structure includes the first conductor 14, the insulating layer 16, and the second conductor 18. On the second conductor 18, for example, a protective layer or a solder resist layer is formed. No problem.

In the step of FIG. 2 of the above-described embodiment, a baking step is provided every time printing is performed. However, the baking step is not always required. Depending on the characteristics of the thick film material, etc., a plurality of printing layers may be fired simultaneously.

The above is merely an embodiment of the present invention, and the present invention can be variously modified without departing from the spirit thereof.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cross section of a main part of a configuration of a thick film multilayer circuit board according to an embodiment of the present invention.

FIG. 2 is a main part process diagram for explaining a main part of a manufacturing process of the thick-film multilayer circuit board of FIG. 1;

FIG. 3 is a cross-sectional view illustrating a configuration of a conventional thick film multilayer circuit board that does not use a raised layer.

[Explanation of symbols]

 10: Thick film multilayer circuit board 12: Ceramic substrate (substrate) 14: First conductor (lower layer conductor) 16: Insulator 18: Second conductor (top layer conductor) 20: Raised layer 22: Alignment mark

Claims (2)

[Claims] 1. A thick film circuit having a multilayer structure in which a substrate, a plurality of types of thick film patterns are sequentially laminated by performing screen printing on one surface of the substrate a plurality of times, and the thick film circuit on one surface of the substrate A thick film multi-layer circuit board, comprising: a thick film multilayer circuit board having a thick film printed at the same time by screen printing of any one of the plurality of times in a portion where no is formed; A thick-film multilayer circuit board formed on a raised layer raised in the thickness direction from the above. 2. A thick film circuit having a multilayer structure in which a substrate, a plurality of types of thick film patterns are sequentially laminated by performing screen printing on one surface of the substrate a plurality of times, and the thick film circuit on one surface of the substrate. A thick film multi-layer circuit board provided with a thick film printed at the same time by any one of the plurality of times of screen printing in a part where the alignment mark is not formed. Raising layer located on the side,
A method for manufacturing a thick-film multilayer circuit board, comprising a step of forming simultaneously with at least one of the thick-film layers constituting the multilayer-film thick-film circuit.