JPH088410B2 - Through-hole printing method for thick film substrate and printed substrate holder - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of printing in a through hole of a thick film substrate in a hybrid integrated circuit and an apparatus directly used for implementing the method.

(Prior Art) Among the hybrid integrated circuits, the one in which the main part of the circuit configuration is made by printing technology is called thick film. A thick film substrate is made by printing a circuit pattern on a ceramic or other insulating substrate using a paste-like thick film paste containing powders of noble metal and glass powder as ink, followed by drying and baking.

When a circuit pattern is printed with a thick film paste on a thick film substrate, the thick film paste is applied not only on the surface of the substrate but also inside the through-holes (small holes that penetrate the substrate) to give the same conduction effect as the circuit pattern. There are the following methods.

That is, the first method is to perform printing by supplying a thick film paste (hereinafter referred to as paste) by silk screen printing (hereinafter referred to as printing) a circuit pattern on a thick film substrate having a through hole (hereinafter referred to as substrate), The paste supplied onto the through holes is a method in which the paste naturally flows into the through holes and the paste is applied to the inside of the through holes to finish printing.

In the second method, the substrate is added to the first method, and the pressure on the lower side of the substrate is reduced during printing as compared with the printing surface to forcibly suck the paste on the substrate into the through holes. Is a method in which the inside of the through hole is coated with paste and printing is completed.

The third method is to manufacture a substrate holder having suction holes at the same positions as the through holes of the substrate, stack the substrate on the substrate holder and fix it, and perform surface printing as in the second method. Then, by depressurizing the lower side of the substrate holder, the paste is forced to flow into the through hole, the paste is applied to the inside of the through hole, and the printing is completed.

(Problems to be Solved by the Invention) However, the conventional printing method as described above has the following problems.

First, in the first method, the paste on the through hole needs to have a low viscosity in order to flow into the through hole. The circuit pattern needs to have a certain degree of viscosity, and it is very difficult to satisfy both. In addition, the paste that has flowed into the through hole rarely evenly flows inside the through hole, and coating leakage easily occurs. On the contrary, when the paste reaches the lower side of the substrate through the through hole, it becomes unnecessary paste and stains the lower side of the substrate.

In the second method, since the lower side of the substrate is depressurized, the paste on the through hole is sucked, flows through the through hole, and is applied with a substantially uniform thickness. However, since the paste flowing in the through hole is sucked from the lower side of the substrate, it flows out to the lower side of the substrate and stains the substrate.

In the third method, since the substrate holder has the suction hole at a position corresponding to the through hole of the substrate, the paste that is sucked and applied to the inside of the through hole is sucked into the suction hole, and the back surface of the substrate becomes dirty. Is less than the first method and the second method. However, this method still has the following problems.

That is, even if the hole position dimensions and the tolerances of the substrate holder and the substrate are the same, the substrate that is a product and the substrate holder for manufacturing are naturally manufactured separately, and the error due to the tolerance is also naturally caused between the substrate and the substrate holder. Then it will be different. Due to this difference, when the substrate and the substrate holder are superposed, the positions of the through hole and the suction hole do not precisely coincide with each other, and the paste can be slightly soiled on the lower side of the substrate. Further, even in the same type of substrate, the finished size varies depending on the lot, so that the lower side of the substrate can be soiled as described above. Further, according to this method, it is necessary to prepare a substrate holder for each different type of substrate, which causes a problem of high cost.

In view of the above-mentioned problems of the prior art, it is an object of the present invention to provide a through-hole printing method in which the paste stain on the back surface of the substrate is further reduced, and a substrate holder for carrying out this method.

(Means for Solving the Problems) In order to achieve the above object, the through-hole printing method and the printed board holder of the present invention have the following means configurations.

(1) The printing method of the present invention is a method of printing with a thick film paste in a through hole of a thick film substrate of a hybrid integrated circuit,
One of the thick film substrates for printing manufactured in the same lot is used as a substrate for thick film paste contamination prevention, and the positions of the through holes of the thick film substrate for printing are aligned on the contamination prevention substrate. Method for printing the through-holes with the thick-film paste by sucking the thick-film paste into the through-holes of the thick-film substrate to be printed by decompressing the atmospheric pressure on the side of the pollution-preventing substrate Is.

(2) In the printed circuit board holder of the present invention, a concave portion having the same shape as the outer periphery of the thick film substrate and having a depth approximately twice the thickness of the thick film substrate is formed on one surface of the plate-shaped structure, Further, a window is provided which is inside the circumference of the recess by a predetermined dimension and extends along the circumference and penetrates to the other surface, and is fitted into the recess on the outside of each of the two sides where the recess intersects. Of the two stacked substrates, an eccentric rotation fixing tool for pressing and fixing the lower layer substrate from the side surface and an eccentric rotation fixing tool for pressing and fixing the upper layer substrate from the side surface are provided for each side.

(Operation) Hereinafter, the operation of the present invention having the above configuration will be described.

First, in the printing method of the present invention, since one of the thick film substrates for printing produced in the same lot is used as the substrate for preventing thick film paste contamination, it is superposed on the thick film substrate for printing. In this case, the positions of the through holes can be almost completely matched. When the positions of the through holes are aligned in this way, the thick film paste is printed on the substrate to be printed, and the atmospheric pressure on the lower side of the substrate for preventing pollution is reduced to suck the thick film paste into the through holes. Almost all is sucked into the suction holes of the prevention substrate and does not remain around the through holes on the back surface of the substrate to be printed, so that there is almost no contamination.

Further, in the substrate holder of the present invention, the pollution prevention substrate and the substrate to be printed are just fitted in the recesses, and the two substrates are separately pressed from the side surfaces to the edges of the two sides where the recesses intersect with each other and fixed. Since an eccentric rotation fixing device is provided, the pollution prevention substrate is placed on the lower side and the thick film substrate for printing is placed on top of it, and the through hole and suction hole are aligned exactly Both boards are fixed by the eccentric rotation fixing tool and the eccentric rotation fixing tool for the upper substrate, the thick film substrate surface to be printed is printed with the thick film paste, and the contamination prevention substrate side is set through the window of the substrate holder. By reducing the pressure, the thick film paste is forcibly sucked into the through hole of the thick film substrate for printing, and the thick film paste that has passed through the through hole is sucked into the suction hole of the contamination prevention substrate. As a result, the thick film paste does not adhere to the back surface of the thick film substrate for printing, and contamination is prevented.

(Examples) Examples of the through-hole printing method of the present invention using the substrate holder of the present invention will be described below.

FIG. 1 is a perspective view of the substrate holder 1. First, the substrate holder 1 has a recess (frame) 3 having the same shape as the outer periphery of the thick film substrate (substantially square in this embodiment) and having a depth twice the thickness of the thick film substrate. A window 2 having a circumference along the circumference of the frame 3 inside the circumference of the frame 3 penetrates to the back surface.

Further, fixing tool mounting holes 4, 4 ', 5, 5'for fitting the eccentric rotation fixing tool and screw holes 10 for mounting the fixing tool are provided on the edges of the two sides of the frame 3 which intersect with each other.

2A is a plan view of the substrate holder, and FIG. 2B is a sectional view taken along the line AA ′ of FIG. The figure (c) shows that the pollution prevention substrate 7 and the thick film substrate 6 to be printed are superposed and fitted into the frame 3 of the diagram (b), the eccentric rotation fixing tool for the lower layer board is fitted in the fixing tool mounting hole 5, and the screw 12 is used. It shows a state in which the pollution prevention substrate 7 is pressed rightward and fixed by being clamped and fixed.

The eccentric rotation fixture 8 for the lower layer substrate is shown in FIG.
It has the structure shown in (b) and (c). FIG. 1A is a perspective view, FIG. 1B is a plan view, and FIG. 1C is a side view. The outer circumference is circular, but the screw hole is provided at an eccentric position instead of the center of the circle. With this, when the screw is fitted into the fixture mounting hole and tightened with the screw, the direction around the screw is selected, so that the contamination prevention substrate 7 is attached to the larger diameter circumferential portion.
The sides of can be pressed. As a result, the substrate 7 is fixed in the frame 3.

FIG. 6D is a cross-sectional view taken along the line BB ′ of FIG. 5A, in which the pollution prevention substrate 7 and the thick film substrate 6 to be printed are superposed and fitted, and the eccentric rotation fixing tool for the upper layer substrate is fitted in the fixing tool mounting hole 4. 9 and screw
Thick film substrate 6 for printing by tightening and fixing with 12 '
Shows the state in which is pressed to the right and fixed. The eccentric rotation fixture 9 for the upper layer substrate is shown in FIG.
It has the structure shown in (e) and (f). That is, the upper and lower portions of the cylindrical portion having a large diameter and the cylindrical portion having a small diameter have a structure opposite to that of the eccentric rotation fixing tool 8 for the lower layer substrate.

FIG. 6D is a perspective view, FIG. 6E is a plan view, and FIG. When the eccentric rotation fixing tool 9 for the upper layer substrate is fitted into the fixing tool mounting hole 4 and tightened with the screw 12 ', the direction around the screw is selected to print on the circumference of the cylindrical portion having the larger diameter. The side surface of the thick film substrate 6 can be pressed. As a result, the substrate 6
Fixed inside. The same thing is done by the eccentric rotation fixing tool 8 for the lower layer substrate and the eccentric rotation fixing tool 9 for the upper layer substrate which are respectively fitted in the fixing tool mounting holes 4'and 5 ', and as a result, the contamination prevention substrate 7 is also applied. Thick film substrate for printing 6
Is firmly fixed by being pressed from two directions orthogonal to each other. Of course, when fixing, the through hole 11 of the thick film substrate 6 to be printed and the suction hole of the substrate 7 for pollution prevention are accurately aligned. Since the contamination prevention substrate 7 uses one of the thick film substrates for printing produced in the same lot, the through hole and the suction hole can be accurately aligned. After fixing both substrates to the substrate holder 1 in this way, the circuit pattern on the surface of the substrate 6 to be printed is printed with a paste, and the air pressure on the window 2 side is reduced to move the paste in the through hole 11 into the through hole. As the inner wall of the through hole is sucked and the excess paste is sucked into the suction hole of the contamination prevention substrate 7, the back surface of the thick film substrate 6 to be printed is not contaminated with the paste. When the printing is completed, the upper layer eccentric rotation fixing tools 9, 9 are loosened and the thick film substrate 6 to be printed is taken out.

 Hereinafter, the same work is repeated to perform printing.

(Effects of the Invention) As described above, in the through-hole printing method of the present invention, one of the thick film substrates for printing, which are produced in the same lot, is used as the substrate for preventing paste contamination. When the thick film substrate for printing and the paste contamination prevention substrate are superposed, the through holes can be almost completely aligned with each other. By depressurizing the contamination prevention substrate side, the surface through hole portion of the thick film substrate for printing Even if the paste applied to the substrate is sucked into the through-hole and printed, the excess paste can almost be sucked toward the suction hole of the contamination prevention substrate, and the back surface of the thick film substrate to be printed can be prevented from being contaminated. The advantage is that

Further, the printed board holder of the present invention has a simple structure and can easily carry out the method of the present invention. Furthermore, as long as the external dimensions and thickness of the substrate to be printed are the same, one substrate holder can print a plurality of types of boards. This makes it possible to shorten the manufacturing period and reduce the cost compared to the conventional case where a substrate holder has to be prepared every time the type of printed substrate changes. There are advantages.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the substrate holder of the present invention, and FIG.
1A is a plan view of the substrate holder of FIG. 1, FIG. 2B is a sectional view taken along the line AA ′ of FIG. 2A, and FIGS. 2C and 2D are fixing of the substrate. FIG. 3 is a structural diagram of the eccentric rotation fixing tool. 1 ... Board holder, 2 ... Window, 3 ... Frame (recess), 4,
4 ', 5,5' ... Fixing device mounting hole, 6 ... Thick film substrate for printing, 7 ... Contamination prevention substrate, 8 ... Eccentric rotation fixing device for lower layer substrate, 9 ... Eccentricity for upper layer substrate Rotating fixture, 10 …… Screw hole, 11 …… Through hole, 12,12 ′ …… Screw.

Claims (2)

[Claims] 1. A method of printing a thick film paste in a through hole of a thick film substrate of a hybrid integrated circuit, wherein one of the thick film substrates for printing manufactured in the same lot is used to prevent thick film paste contamination. It is used as a substrate for printing, and the thick film substrate for printing is stacked and fixed on the substrate for pollution prevention so that the positions of the through holes are aligned with each other. A through-hole printing method for a thick film substrate, wherein the through hole is printed with the thick film paste by sucking the thick film paste into the through hole of the thick film substrate. 2. A plate-shaped structure is provided on one surface thereof with a recess having the same shape as the outer periphery of the thick-film substrate and having a depth approximately twice the thickness of the thick-film substrate. A window is provided that has a circumference along the circumference inside by a predetermined dimension and penetrates to the other surface, and a stack of two sheets fitted in the recess is provided outside each side of the two sides where the recess intersects. A printed circuit board holder having, for each side, an eccentric rotation fixing tool for pressing and fixing the lower layer substrate from the side surface and an eccentric rotation fixing tool for pressing and fixing the upper layer substrate from the side surface.