JPS5823495A - Thin film printing screen - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a thick film printing screen for printing a predetermined circuit pattern on the surface of a substrate in a thick film integrated circuit.

Generally, integrated circuits are broadly divided into monolithic integrated circuits and hybrid integrated circuits. This hybrid integrated circuit allows for combinations of elements with various optimal electrical characteristics compared to monolithic integrated circuits, and also enables circuit configurations that have both digital and analog functions (for example, filters). It has many advantages. Such a hybrid integrated circuit is usually a thick film integrated circuit formed by thick film integration technology, and this thick film integrated circuit (hereinafter simply referred to as an integrated circuit) has a resistor on a ceramic substrate. This is an electronic circuit in which individual components such as capacitors are formed as printed films using a screen printing method.

In this screen printing method, first, as shown in FIG. 1, a screen 12 made of metal such as stainless steel is usually placed parallel to the substrate 11 with a slight gap from the surface of the substrate 11. This screen 12 has a printed pattern corresponding to the circuit pattern of the integrated circuit! 3
That is, the screen 12 is provided with openings, and the surface of the screen 12 is provided with a mesh (hereinafter referred to as mesh) 14 made of thin metal wires such as stainless steel.
is formed. Then, as shown in FIG. 2, the paste 15 applied on the screen 12, that is, the printed film material (for example, made of metal oxide and organic solvent) forming elements such as resistors and capacitors, is applied with a squeegee 16. , and stretch it onto the screen 12. This squeegee 1
The tip of 6 is made of square rubber 17, such as polyurethane rubber, and is usually angled at 45 degrees. Paste 14 stretched by this squeegee 16
is printed on the substrate 1 according to the printed pattern 13 on the screen 12.
1 as a printed film. At this time, paste 1
4 are not attached to the substrate 11 all at once by the mesh 14, but are attached to the mesh 1 according to the pressure of the squeegee 16.
4 to form a uniform thick film.

Further, the screen 12 comes into contact with the surface of the substrate 11 by the pressure of the squeegee 16, and returns to its original position by the elasticity of the mesh 14 after printing.

In this way, a thick film integrated circuit can be constructed by forming a printed film having a desired circuit pattern on the surface of the substrate 11. However, with this conventional screen printing method,
Stretch the paste 14 with the squeegee 16 and paste it onto the board J7-
Air is often trapped in portions 18 of the printed pattern 13 of the screen 12 when forming a printed film thereon.

By the way, since the thickness of the printed film formed on the substrate 11 corresponds to the thickness of the screen 12, when the printed film thickness is relatively thin, the volume of the trapped air is small. In this case, air can escape from the gap between the screen 12 and the substrate 11, but the printed film thickness is, for example, 100 μm.
In the case of a thick film such as that shown in FIG.
If there is only a gap, the air will not be able to escape and will remain. Therefore, there are drawbacks such as a printed film not being formed at necessary locations on the surface of the substrate 11.

This invention was made in view of the above circumstances, and is a thick film printing method that can form a stable thick printed film on the surface of a substrate by removing air trapped in the printed pattern part of the screen in the screen printing method. I can provide a screen for use.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 3(A) is an actual image of the screen 12 according to one embodiment, which shows the configuration of the surface corresponding to the substrate surface during thick film printing - 113 is a printed pattern corresponding to the circuit pattern of the thick film integrated circuit. It is. This printed pattern 13 is usually provided in plural numbers and is formed on the plate-shaped screen 12 body made of stainless steel or the like by an etching method or the like.

Then, it is connected to this printing pattern 13, and the screen 1
For example, on the back side of 2, there is an arrow JJ indicating the printing direction (Fig. 3 C).
) are provided with a plurality of grooves 32 in parallel. This groove 32 is
Like the printed pattern 13, it is formed by an etching method or the like, and is usually formed at the same time as the printed pattern 13. Further, as shown in FIG. 3(B) (cross-sectional view), if the width a of the printed pattern 13 is, for example, about 3 mm, the groove 32
The width of the groove 32 is approximately 0.1111 to 0.2 mm, and if the thickness d of the screen 12 body is, for example, approximately 0.211B, the depth e of the groove 32 is approximately 0.05111 mm. It is. Note that, similarly to the above, when forming a printed film according to the circuit pattern of an integrated circuit on a substrate using such a screen 12, which is provided with a mesh 14, the explanation of which will be omitted, first the mesh 14 is provided on the screen 12. A paste is applied onto the surface of the screen 12 in the same manner as shown in FIG. 2, and when this paste is stretched by the pressure of a squeegee, the paste adheres to the substrate through the printed pattern 13 of the screen 12.

At this time, a part of the print pattern 13 on the screen 12,
In other words, air is trapped in the front part in the printing direction, which is the direction in which the squeegee moves, surrounded by the substrate, screen 12, and paste;
It escapes from inside the printed pattern 13 through the groove 32 provided in the groove 32 and is removed. Therefore, the paste stretched by the squeegee is
The printed film is deposited on the substrate surface as a printed film having a sufficient film thickness according to No. 3. At this time, the paste adheres to the surface of the substrate corresponding to the portion of the multi-receiving groove 32, but this can be completely ignored in view of the accuracy of a normal circuit pattern of a thick film integrated circuit.

In addition, in the above embodiment, the grooves 32 provided on the back surface of the screen 12 are not limited to being parallel to the printing direction, but are connected to the printed pattern 13, and the grooves 32 provided on the back surface of the screen 12 are connected to the front part in the printing direction inside this printed pattern 13. The width and depth of the grooves 32 are not limited to this example, and may vary depending on the thickness of the screen 12 and the printed pattern. It may be set according to the size of 13, etc.

As described in detail above, according to the present invention, in the screen printing method, when the paste is stretched by the pressure of the squeegee, grooves are provided to remove air trapped in the printed pattern portion of the screen, so that the desired surface is formed on the substrate surface. It is possible to provide a thick film printing screen that can form a printed film having a sufficient film thickness depending on the circuit pattern, thereby forming a stable thick film integrated circuit.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional thick film printing screen, Fig. 2 is a diagram explaining a method of forming a thick film integrated circuit by the conventional screen printing method, and Fig. 3 (Al, A configuration diagram of a thick film printing screen according to an embodiment,
(Figure A1 is a plan view, and Figure (B) is a cross-sectional view. 11... Substrate, 12... Screen, 14... Mesh, 15... Paste, 16... Squeegee, 3
2... Groove.

Claims (1)

[Claims] In a printing screen for forming a thick film integrated circuit on the surface of a substrate, a printed pattern formed according to the configuration of the integrated circuit, and a screen formed in contact with this printed pattern and provided on a surface corresponding to the surface of the substrate. A screen for thick film printing, characterized in that it is equipped with an exhaust groove.