JPS60214591A - Screen printing machine - 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 INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to a screen printing machine for producing thick film circuits that can be used in radios, televisions, video tape recorders, etc.

Conventional structure and problems thereof FIG. 1 shows an example of a thick film circuit. The thick film paste printed on the alumina substrate 1 is dried and fired to form a thick film conductor layer 2. A thick film resistor 3 is formed. Thick film paste I for conductors is generally composed of silver-palladium alloy powder, glass frit, resin binder, organic solvent, etc. Ruthenium oxide is used in place of the silver-palladium thick film paste for the resistors, and the rest is made up of approximately the same paste as the conductor paste. A chip capacitor 4 is mounted on a thick film conductor layer 2 with solder 6 on an alumina substrate 1.
is connected to. With the recent demand for smaller electronic devices, there is an increasing need for circuit boards used there to be smaller and more highly integrated. Therefore, as shown in Fig. 1, from the conventional general board that uses only one side to the one shown in Fig. 2, a thick film conductor layer 23 formed in the through hole 6 in the alumina substrate 1 is used to cover both sides of the board. Effective use of double-sided thick film circuits has come into use.

The screen printing machine used in the conventional manufacturing process of double-sided thick film circuits has a board thickness of 0.5++++, as shown in Figure 3.
+1 to 0.6 alumina substrates 1 are set on the substrate fixing stage 10, and the silver-palladium paste 2 is spread on the screen 8 using an ink spatula 7, and the suction port 11 is spread with one squeegee 9. A method generally used is to apply the conductive paste 2 to the conductor circuit portion 13 and through holes 6 on the substrate while drawing a vacuum. However, in this method, the paste is spread over the entire surface of the screen, and when the squeegee starts suctioning while descending, the entire surface of the screen is attracted to the substrate and the paste is sucked from the patterned part of the screen, and the paste adheres to the emulsion 12, causing bleeding. There are cases where In particular, when the squeegee is printed, the suction time is longer for the pattern portion at the end of printing compared to the initial position, so the amount of paste that smudges out is large and causes smearing. Furthermore, if the suction force is reduced in order to reduce the amount of paste smearing out, the smearing in the pattern area tends to decrease, but there is a problem in that the paste is not sufficiently applied within the through-holes. As shown in Figure 4, in conventional screen printing, at the beginning and end of printing, the suction force is maximum at the former and decreases as it approaches the latter.
The above-mentioned problem occurs because the suction force is not constant during printing.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a screen printing machine which solves all of the drawbacks mentioned in (-) and simultaneously prints a conductor pattern on a substrate and coats a conductor inside the through-hole, thereby eliminating smearing on the conductor pattern and increasing the reliability of the through-hole. The purpose is to

Structure of the Invention The present invention provides a stage for fixing a board, which is provided to fix a board and to be able to draw vacuum from one side of the board, and a stage which can come into contact with the other side of the board, and on which a conductor paste is placed. and a squeegee capable of applying conductor paste on the screen to the substrate by vacuum suction of the substrate fixing stage, The squeegee is configured to be able to move back and forth and to have the conductive paste on the moving direction side, and the suction pressure is constant from the start of printing to the completion of printing, so that a substrate with high printing accuracy can be obtained.

DESCRIPTION OF EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. An alumina substrate 1 with a substrate size of 100Tn100Tn'' x 0.8t7 and a through hole 6 with a diameter of 0.6- is set on the substrate fixing stage 1°, and while suctioning with a vacuum pump from the suction port 11 is applied to one side 9a of the squeegee. Apply silver-palladium paste with a squeegee down stop 0.5 m over the 360 mesh stainless steel screen 8 attached to the mounting frame 14 holding the screen,
Screen printing is performed at a speed of 7 seconds, and after printing is completed, the squeegee 9 is raised 2" and the other side 9b of the squeegee is moved over the paste 2 to a position where it can be printed for 6 pages, and the printed substrate is ejected. As shown in the figure, a new alumina substrate 1' is set on the substrate fixing stage 10 in the same way as in the outward printing, and the silver-palladium paste 2 used in the outward printing is applied to the other side 9b of the squeegee 9 in the same way as in the outward printing. Perform screen printing on the screen, and raise the squeegee 9 in the same way as after completing the outward printing, and remove the paste 2" from the squeegee 9.
As a result, as shown in Figure 4, in screen printing according to the present invention, the suction pressure is constant because the paste is not spread on the screen in advance. Therefore, the printing conditions were exactly the same on the outward and return passes, and a good product with no bleeding and a through-hole yield of 100% was obtained.

Next, a second embodiment of the present invention will be explained with reference to FIG. An alumina substrate 1 having a through hole 6 with a diameter of 0.6 mm and the same substrate size as in the first embodiment is mounted on a stage 1o for fixing the substrate.
Set the silver-palladium paste 2 to 36 degrees by setting the angle of the squeegee 9 to 7 degrees from the 7 pen board while suctioning from the vacuum pump through the suction port 11.
Screen printing is performed on the conductor circuit section 13 on the board and the inside of the through hole 6 using a 0-mesh stainless steel screen 8, and in the latter half, the squeegee 9 is raised and printing on the paste 2 is possible with the other side 9b of the flat squeegee 9. The angle of the flat squeegee 9b is changed so that the surface of the flat squeegee 9b is 70 degrees from the substrate, the printed substrate is ejected, and a new alumina substrate 1' is placed on a new alumina substrate 1' as shown in FIG. Similarly, the silver-palladium paste 2, which was set on the substrate fixing stage 10 and used in the forward printing, was screen printed on the 9b side of the squeegee 9 in the same manner as the forward printing. As a result, the same printing result as in the first example was obtained. It was done.

Note that the squeegee angle is not a key point of the present invention, and is variable from 30 degrees to 90 degrees from the substrate surface, and is not limited to 70 degrees.

Effects of the Invention As described above, according to the present invention, unlike conventional screen printing machines, the paste is not spread on the screen by ink return in advance, and the suction pressure remains constant from the start of printing to the completion of printing, resulting in extremely high printing accuracy. A good substrate can be obtained. Furthermore, whereas in the past, printing was performed once in one reciprocation of the squeegee, in the present invention, printing can be performed twice in the forward and backward passes, thereby improving productivity.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing an example of a thick film circuit, Fig. 2 is a cross-sectional view showing a thick film circuit using both sides of a substrate, Fig. 3 is a cross-sectional view of a conventional screen printing machine, and Fig. 4 is a conventional screen printing machine. Figure 5 is a diagram showing the relationship between the squeegee position and the vacuum suction force in the screen printing machine of the present invention and the screen printing machine of the present invention.
FIG. 6 is a sectional view of the apparatus for carrying out the embodiment during forward printing; FIG. 7 is a sectional view of the apparatus for carrying out the second embodiment of the present invention during outward printing; FIG. FIG. 8 is a cross-sectional view of the same during backward printing. 1...Alumina substrate 1/, old...new alumina substrate, 2...Silver-palladium paste, 7
・River...Ink return, 8...Screen, 9.
River: squeegee, 1o: board fixing stage, 11: river: suction port, 9 () 13: conductor circuit section, 14: mark: mounting frame. Name of agent: Patent attorney Toshio Nakao (1 person)
- Figure 4 swipe → 581 Figure 6

Claims (1)

[Claims] (1) A board fixing stage that fixes the board and is capable of vacuum suction from one side of the board, and a screen that can come into contact with the other side of the board and on which conductive paste can be placed. , a screen printing machine comprising a squeegee capable of applying conductive paste on the screen to the substrate by vacuum suction of the substrate fixing stage through the screen, the squeegee being capable of reciprocating movement and facing the direction of movement; A screen printing machine configured to include the conductor paste. (≧ The screen printing machine according to claim 1, wherein the squeegee is provided so that after moving in one direction, the squeegee is moved up, further moved in the same direction by a predetermined amount, and then lowered and moved in the opposite direction.