JPH06120638A - Thick film printed board - Google Patents

Abstract

PURPOSE:To realize a thick film printed board in which the deterioration of surface insulation between conductors, resist film effect, and pattern can be retarded while preventing short circuit of pattern. CONSTITUTION:A print pattern is formed having an acute outer edge part 5 on one edge part of a board 1. A plurality of patterns are laminated by a plurality of upper layer print patterns at different positions in the extending direction of the plurality of print patterns. This arrangement improves the printing of dielectric film and prevents the laminated part from being smeared with paste.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is a hybrid I
The present invention relates to a thick film printed circuit board used for C or the like, and particularly to the shape of its pattern.

[0002]

2. Description of the Related Art Conventionally, a thick film printed circuit board of this type has been constituted by a conductor pattern formed parallel and perpendicular to the edge of the board, as shown by the plane inductance in FIG.

The method of forming this thick film printed circuit board is as follows. First, an insulating substrate such as ceramic (1)
Conductor pattern (3) including soldering lands (2) on top
As a conductive paste such as copper or silver-palladium, a predetermined shape is applied by screen printing. Then, after the conductive paste is dried, the substrate (1) is baked in a baking furnace to burn the conductive paste. Next, an insulating material such as silicon is applied to the entire area of the substrate (1) excluding the soldering lands (2) by screen printing in the direction of the arrow in FIG. 3) is covered with an insulating film (4) as shown in FIG.

Thus, the insulating film (4) for covering the surface of the thick film printed board has a moisture-proof effect on the conductor pattern (3),
Insulation effect between conductor patterns (3) with narrow spacing,
And, when it is formed on the periphery of the soldering land (2) except for it, there is a resist film effect and the like, and it is necessary to maintain the electrical characteristics of a fine circuit in a thick film printed circuit board with a fine pattern. It cannot be done.

As another conventional example, as shown in FIG.
A thick film printed circuit board having an IC mounted on the circuit board will be described through a manufacturing method. This thick film printed circuit board is
A plurality of bonding pads (9) arranged in parallel are formed on the four sides surrounding the C mounting portion (8) by screen printing with a gold-based conductive paste. At this time, a resistor (not shown) is similarly formed from a ruthenium oxide-based conductive paste. Next, a conductor pattern (3) for wiring is formed by screen printing with a silver-palladium-based conductive paste so as to partially overlap the bonding pad (9). Such a thick film printed circuit board is also coated with an insulating film after forming all other patterns. The lead terminal of the IC and the bonding pad (9) are electrically connected by welding a bonding wire made of a gold-based material to each.

By the way, the above-mentioned screen printing is a method in which a screen in which holes are provided only in a portion to be printed is brought into close contact with the surface of a substrate and a coating material is gradually applied from one direction onto the surface of the substrate. Is printed in a direction parallel to one edge of the substrate.

[0007]

However, the thick film printed circuit board shown in the first conventional example described above has the conductive pattern (3) formed in the previous step in the step of printing the insulating film.
When the insulating coating is applied to the surface of the substrate (1) which is uneven due to the conductor pattern (parallel to or perpendicular to the edge (6) of the substrate (1) as shown by the wavy line portion in FIG. 3), that is, a part of the outer edge portion (5) of the conductor pattern (3) formed orthogonally to the screen printing direction and the concave portion between these patterns are difficult for the paint to enter, so that the paint is completely or sufficiently Sometimes it was not applied. And in the printed circuit board where the space between the conductor patterns (3) is narrow,
This drawback was more prominent.

In such a thick-film printed circuit board, the surface insulation between the conductors is apt to deteriorate, and the resist film effect is weakened on the substrate (1) around the soldering land (2), so that the conductor film is separated from other conductors. Therefore, a solder bridge is likely to occur. When the conductor pattern (3) was completely exposed, the conductor pattern (3) deteriorated due to moisture.

In addition, the thick film printed circuit board shown in the second conventional example described above has a pattern formed on the printed pattern of the bonding pad (9).
When the upper layer print pattern of the conductor pattern (3) is partially overlapped and screen-printed in the direction of the arrow in FIG. 6, the portion indicated by the wavy line in FIG.
Since the edges of the printing start direction side are lined up in a row, the running resistance of the printing squeegee to which the paste is applied increases at this portion, and stable follow-up is impeded, causing running unevenness. As a result, bleeding may occur in the laminated portion (10) of the bonding pad (9) and the conductor pattern (3) due to the paste forming the conductor pattern (3). Then, the laminated portion (10) in which such bleeding occurs
In this case, the insulation between the patterns was poor and a pattern short circuit sometimes occurred.

Therefore, according to the present invention, by improving the pattern shape of the thick film printed board, it is possible to prevent the generation of the portion where the insulating film is not formed, to deteriorate the surface insulation between the conductors, to reduce the resist film effect, and to improve the pattern. By reducing the deterioration of the pattern and improving the pattern shape in the same way, the bleeding of the paste printed later on the pattern is prevented,
An object of the present invention is to provide a thick film printed board that can prevent the occurrence of pattern short circuits.

[0011]

In order to achieve the above object, the invention according to claim 1 of the present application is a thick film printed circuit board comprising a substrate and a print pattern formed by printing on the substrate, At least an outer edge portion of the print pattern is formed in an acute angle with respect to one edge portion of the substrate.

[0012] Yes.

Further, in the invention according to claim 2, in a thick film printed board provided with a plurality of juxtaposed patterns and a plurality of upper layer print patterns laminated on each of the print patterns, the adjacent print patterns are provided. And a laminated portion of the upper print pattern and the upper print pattern are formed at different positions in the extending direction of the plurality of print patterns.

[0014]

[Function] Generally, the direction of screen printing on the substrate is
Since it is performed in parallel or orthogonal to at least one edge of the substrate, by forming a pattern line segment in the direction of an acute angle with respect to the edge of the substrate, as in the thick film printed substrate of the present invention, The insulating layer printed on the upper layer is printed from a direction oblique to the pattern edge of the pattern line segment. Therefore, the insulating film is satisfactorily applied at the pattern edge, and the uncoated part and the thin part of the layer do not occur. Therefore, deterioration of the surface insulation between conductors, weakening of the resist film effect, and deterioration of the pattern are prevented. be able to.

Further, by forming a laminated portion of a plurality of adjacent print patterns and a plurality of upper layer print patterns at different positions in the extending direction of the plurality of print patterns, the respective print patterns can be formed. Since the end portion does not hit the print squeegee at the same time, the running resistance of the print squeegee can be suppressed to a low level even at the end portion of the print pattern, and the stable running of the print squeegee can be obtained. By doing so, it is possible to prevent bleeding in the laminated portion of the paste formed as the upper layer print pattern and prevent the occurrence of pattern short circuits.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As an example of a thick film printed circuit board according to the present invention, a thick film printed circuit board having a plane reactance as shown in FIG. 1 will be described through its manufacturing method.

The method of forming this thick film printed circuit board is as follows. First, an insulating substrate such as ceramic (1)
Conductor pattern (3) including soldering lands (2) on top
For example, a copper-based or silver-palladium-based conductive paste is printed by screen printing in the direction of the arrow in the figure to form a hexagonal spiral shape as shown in FIG. Then, after the conductive paste is dried, the substrate (1) is heated in a baking furnace at about 600 to 700 ° C. to burn the conductive paste.

Next, an insulating material such as silicon is applied to the entire area of the board (1) excluding the soldering lands (2) in the direction of the arrow in FIG. 1, that is, perpendicular or parallel to the edge of the board. From different directions by screen printing, and
As shown in FIG. 2, which is a sectional view taken along line A ′, the conductor pattern (3)
Is covered with an insulating film (4).

Such a thick film printed circuit board, as shown in the region (a) of FIG. 1 at the time of printing the insulating film (4),
The outer edge part (5) of a part of the conductor pattern (3) is formed in an acute angle shape with respect to one edge part of the substrate (1), that is, the end side (6) shown in FIG. Conductor pattern (3) formed in a direction oblique to one edge of the substrate (1)
Is an insulating film printed on the upper surface of the pattern (3).
Since the printing is performed in an oblique direction with respect to the pattern (3), the insulating film is satisfactorily applied to the outer edge portion (5) of the pattern of the line segment (3), and there is no uncoated portion or thin portion of the insulating film. It is possible to prevent deterioration of surface insulation between conductors, weakening of resist film effect, and deterioration of pattern.

By the way, the conductor pattern (3) shown in the area of the wavy line in FIG. 1 in the above embodiment is formed by partially including the curved portion (7) as shown in the area (b) of FIG. However, the same effect as above can be obtained.

Next, another embodiment of the present invention will be described through a manufacturing method with reference to FIG. First, on an insulating substrate made of an alumina material or the like, a plurality of bonding pads (9) arranged in parallel on four sides surrounding the chip IC mounting portion (8) are formed by a gold-based conductive paste in the figure. Apply by screen printing in the direction of the arrow.
At this time, a resistor or the like (not shown) is similarly applied to the other wiring portions. Then, the substrate (1) on which the above conductive paste is printed is placed in a baking furnace at about 600 to 700 ° C. to burn the conductive paste.

Next, the conductor pattern (3) for wiring is formed of silver.
A palladium-based conductive paste is applied by screen printing in the direction of the arrow in FIG. At this time, the conductive paste is formed on the bonding pad 9 formed previously.
In order to surely make an electrical connection with, the coating is applied so as to slightly overlap the bonding pad (9). Then, the conductive paste is put into the firing furnace again to fire the conductive paste.

Such a thick film printed substrate is also coated by applying an insulating film screen printing of silicon or the like after forming all the patterns on the substrate.

Each electronic component is mounted by being fixed by soldering on a thick film printed circuit board on which all patterns are formed. For example, a chip IC (not shown) is adhesively mounted on the chip IC mounting portion (8) shown in FIG. T of this thick film printed board. Then, the lead terminal of the chip IC and the bonding pad (9) are electrically connected by welding a bonding wire made of a gold-based material to each.

As described above, a plurality of laminated portions (1) of the printing pattern of the bonding pad (9) and the upper layer printing pattern of the conductor pattern (3) which are formed so as to partially overlap each other.
0) are arranged at different positions with respect to the extending direction of the bonding pads (9), that is, the ends of the respective bonding pads (9) do not hit the printing squeegee at the same time. The running resistance of the printing squeegee at the end of the bonding pad (9) can be kept low, and stable running of the printing squeegee can be obtained. Therefore, it is possible to prevent the paste formed as the conductor pattern (3) from bleeding and prevent the occurrence of a pattern short circuit.

[0026]

As described in detail above, according to the present invention,
By forming a pattern line segment in the direction of an acute angle with respect to the edge of the substrate, the insulating film printed on the upper layer does not have a part where the insulating film is not applied or a thin layer does not occur, so the surface insulation between conductors deteriorates. The resist film effect is weakened, and deterioration of the pattern can be prevented, and a plurality of laminated portions of a print pattern and an upper layer print pattern formed so as to partially overlap each other are provided. By forming at different positions with respect to the extending direction, it is possible to provide a thick film printed board capable of preventing the bleeding of the upper layer printed pattern in the laminated portion and preventing the occurrence of a pattern short circuit.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a thick film printed board according to the present invention.

FIG. 2A of an embodiment of a thick film printed circuit board according to the present invention
It is an A'sectional view.

FIG. 3 is a plan view showing a modified example of the embodiment of the thick film printed circuit board according to the present invention.

FIG. 4 is a plan view showing another embodiment of the thick film printed circuit board according to the present invention.

FIG. 5 is a plan view showing a thick film printed circuit board in the prior art.

FIG. 6 is a plan view showing another thick film printed circuit board in the prior art.

[Explanation of symbols]

1 ... Board, 2 ... Soldering land, 3 ...
Conductor pattern, 4 ... Insulating film, 5 ... Outer edge,
6 ... edge, 7 ... curved portion, 8 ... chip IC
Mounting part, 9 ... Bonding pad, 10 ...
Laminated part

Claims (3)

[Claims] 1. A thick film printing substrate comprising a substrate and a printing pattern formed by printing on the substrate, wherein at least an outer edge portion of the printing pattern has an acute angle with respect to one edge portion of the substrate. A thick film printed circuit board characterized by being formed. 2. A thick film printing substrate comprising a plurality of adjacent patterns and a plurality of upper layer print patterns laminated on each of the print patterns, wherein the adjacent print patterns and the upper layer print patterns are laminated. The parts are formed at different positions in the extending direction of the plurality of print patterns, respectively. 3. A thick film printing comprising a substrate, a print pattern formed on the substrate by screen printing, and an insulating film formed on the substrate by screen printing so as to cover the surface of the pattern. In the substrate, at least an outer edge portion of the print pattern is formed in an acute angle shape with respect to one edge portion of the substrate, the thick film printed board.