JP3146496B2 - Method of forming through-hole electrode on insulating substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a through-hole electrode on an insulating substrate which is generally used for forming terminal electrodes and wiring conductors of multi-element electronic components and thick film hybrid ICs in recent years.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for electronic components to be lighter, thinner and shorter with the miniaturization of electronic devices. To increase the mounting density and mounting efficiency on circuit boards, very small electronic devices have been required. There has been an increasing demand for chip electronic components composed of.

A conventional method of forming a through-hole electrode will be described below. FIG. 3 is a schematic view showing a conventional insulating substrate, in which 11 is a print effective area, 12 is a through hole, and 13 is a print unnecessary area. FIG. 4 is a schematic diagram of a through-hole printing method.
First, an insulating substrate 14 as shown in FIG. 3 is placed on a stage 15 of a printing machine, and a conductive paste 17 is printed by using a screen printing method. After printing the conductor paste on the inner wall of No. 18, it is dried and fired. Next, the same operation was performed on the surface opposite to the previous surface by inverting the insulating substrate, and the conductive paste was overlapped with the conductive paste on both surfaces to conduct the electric current, and then dried and fired to form a through-hole electrode.

[0004]

However, due to recent miniaturization of electronic components, the external dimensions of products have become smaller, and accordingly, the diameter of through holes for forming through-hole electrodes has to be reduced. Therefore, in the conventional method of forming a through-hole electrode using an insulating substrate, FIG.
When a through-hole electrode is formed by screen printing as shown in the figure, when the conductive paste is gradually printed on the through-hole from the printing start side, the diameter of the printed through-hole is smaller than the diameter of the unprinted through-hole. In order to achieve this, the suction pressure is concentrated on the large-diameter through-hole on which the conductive paste is not printed. Therefore, since the suction pressure in the through hole on the printing start side and the suction pressure in the through hole on the printing end side are not equal, the through-hole electrode cannot be formed uniformly in the printing effective area of the insulating substrate. There has been a problem that it becomes remarkable as the diameter of the through hole becomes smaller.

[0005] The present invention is intended to solve such a problem, an insulating base for uniformly forming a through hole electrode in the effective printing region of the insulating substrate having a small hole diameters
An object of the present invention is to provide a method for forming a through-hole electrode on a plate .

[0006]

In order to achieve this object, a method of forming a through-hole electrode on an insulating substrate according to the present invention comprises providing a plurality of through-holes penetrating from a front surface to a back surface for forming a through-hole electrode. An insulating substrate having a print-effective area and a print-unnecessary area formed as a frame surrounding the print-effective area, and having at least one or more through-holes penetrating from the front surface to the back surface in the print-unnecessary area. At the same time, the conductor pattern is printed on the inner wall of the through-hole in the printing effective area of the insulating substrate by simultaneously performing the screen printing of the electrode pattern using the conductor paste on both sides of the printing effective area while suctioning from the opposite side to the printing surface. A hole electrode is formed.

[0007]

According to the above method for forming a through-hole electrode on an insulating substrate, at least one or more through-holes penetrating from the front surface to the back surface are provided in the non-printing area of the insulating substrate, and conductors are provided on both sides of the printing effective area on the insulating substrate. At the same time as forming the electrode pattern by screen printing using the paste, the conductive paste is printed on the inner wall of the through-hole in the printing effective area of the insulating substrate while sucking from the side opposite to the printing surface so as to form a through-hole electrode. Therefore, even if the conductive paste is gradually printed from the printing start side to the through-hole in the printing effective area and the diameter of the printed through-hole becomes smaller than the diameter of the unprinted through-hole, the conductive paste is provided in the printing unnecessary area. Due to the presence of the through-holes, the suction pressure is provided in the print-unnecessary area without concentrating on the through-holes where the conductor paste is not printed in the print effective area. Since the suction pressure does not become extremely high in the through hole on the printing end side in the effective printing region, the through-hole electrode is uniformly distributed in the effective printing region of the insulating substrate. It can be formed in.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for forming a through-hole electrode on an insulating substrate according to an embodiment of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is used in a method of forming a through-hole electrode according to the present invention .
FIG. 2 is a schematic diagram illustrating an insulating substrate according to the first embodiment . 1 is a printable area, 2 is a plurality of through holes provided in the printable area 1 so as to penetrate from the front surface to the back surface, 3 is a print unnecessary region, and 4 is provided in the print unnecessary region 3 so as to penetrate from the front surface to the back surface. A plurality of through holes. First, 50mm in length, 60mm in width,
An insulating substrate made of alumina as shown in FIG. 1 and having a thickness of 0.4 mm was prepared. At that time, the number of holes in the print effective area 1 is 1280.
Pieces, the hole diameter is 0.2 mm, and the number of holes in the print unnecessary area 3 is 32.
The individual and the hole diameter are 0.3 mm. A commercially available thick film silver paste is used as the conductor paste. For plate making for printing, a stainless screen mask having a rectangular pattern having the same center point with respect to a hole diameter of 0.2 mm is prepared. FIG. 4 shows a schematic diagram of the printing method.

First, the above-mentioned insulating substrate 14 is placed on a stage 15 of a printing machine as shown in FIG. 4, and the conductive paste 17 is screen-printed by using the above-mentioned mask 19 while being sucked by a suction blower 16 from below. While changing the suction pressure, the suction pressure is determined by observing the state of the paste inserted into the inner wall of the through hole 18 provided in the print effective area.

Next, after drying in a dryer at 120 ° C. for 10 minutes, baking is performed with a profile having a peak temperature of 850 ° C.

After that, the insulating substrate 14 is turned over, the conductive paste 17 is printed in the same manner as described above, an overlapped portion is formed on the inner wall of the through hole, and the conductive paste 17 is dried.
Baking is performed at a profile of 50 ° C. to form a through-hole electrode.

After that, as a result of observing the through-hole electrode with a stereoscopic microscope, it was found that bleeding caused by an increase in suction pressure near the through-hole in the conventional through-hole electrode forming method and through-hole failure due to clogging of the conductive paste with the through-hole were observed. Compared to the occurrence rate of about 30%, the defective rate in the method for forming a through-hole electrode on an insulating substrate according to the present embodiment could be improved to several percent or less.

Embodiment 2 FIG. 2 is used in a method of forming a through-hole electrode according to the present invention .
FIG. 9 is a schematic diagram illustrating an insulating substrate according to a second embodiment . 5 is a first print effective area, 6 is a plurality of through holes provided in the first print effective area 5 so as to penetrate from the front surface to the back surface, 7 is a second print effective area, and 8 is a second print effective area. A plurality of through holes are provided in the region 7 so as to penetrate from the front surface to the back surface, 9 is a print unnecessary region, and 10 is a plurality of through holes provided in the print unnecessary region 9 so as to penetrate from the front surface to the back surface. When a through-hole electrode was formed in the same manner as in the first embodiment of the present invention, similar results were confirmed.

In the first and second embodiments, in forming the through-hole electrodes, the electrode formation by the through-hole printing on the front surface and the electrode formation by the through-hole printing on the back surface are performed at 850 ° C. in separate steps. After firing,
After printing the surface through-hole and drying at 120 ℃,
After printing the back side through-hole and drying at 120 ° C, 8
Co-firing may be performed at 50 ° C.

[0016]

As is apparent from the above description, the method for forming a through-hole electrode on an insulating substrate according to the present invention provides at least one or more through-holes penetrating from the front surface to the back surface in the non-printable area of the insulating substrate. An electrode pattern is screen-printed using conductive paste on both sides of the printable area of the insulating substrate, and simultaneously the conductive paste is printed on the inner wall of the through hole in the printable area of the insulating substrate while sucking from the opposite side to the printing surface. Since the through-hole electrode is formed, the diameter of the printed hole is gradually increased from the printing start side by printing the conductive paste in the through-hole in the printing effective area, and the diameter of the printed hole is smaller than the diameter of the unprinted hole. Even if it becomes smaller, due to the presence of the through hole provided in the print unnecessary area,
The suction pressure is not concentrated on the through holes where the conductive paste is not printed in the print effective area, but is also distributed to the through holes provided in the print unnecessary area, thereby, the print end side in the print effective area on the printing end side. Since the suction pressure does not become extremely high in the through-hole, the through-hole electrode has an excellent effect that the through-hole electrode can be uniformly formed in the printing effective area of the insulating substrate.

[Brief description of the drawings]

FIG. 1 is used in a method of forming a through-hole electrode according to the present invention .
FIG. 1 is a schematic diagram illustrating an insulating substrate according to a first embodiment .

FIG. 2 is used in the method of forming a through-hole electrode of the present invention .
FIG. 2 is a schematic diagram illustrating an insulating substrate according to a second embodiment .

FIG. 3 is a schematic view showing a conventional insulating substrate.

FIG. 4 is a schematic diagram of a through-hole printing method.

[Explanation of symbols]

 1 print effective area 2 through hole provided in print effective area 3 print unnecessary area 4 through hole provided in print unnecessary area

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho-59-78646 (JP, U) Japanese Utility Model Sho 63-110062 (JP, U) Japanese Patent Publication No. 2-50637 (JP, B2) (58) Field (Int.Cl. ⁷ , DB name) H05K 3/40 H05K 1/11

Claims (1)

(57) [Claims] 1. A printing effective area provided with a plurality of through holes penetrating from a front surface to a back surface for forming a through-hole electrode, and a printing unnecessary area formed as a frame surrounding the printing effective area, In an insulating substrate having at least one or more through-holes penetrating from a front surface to a back surface in a printing unnecessary area, an electrode pattern is screen-printed using a conductive paste on both sides of a printing effective area on the insulating substrate, and a surface on which printing is performed at the same time. A method for forming a through-hole electrode in an insulating substrate, wherein a conductive paste is printed on the inner wall of the through hole in the printing effective area of the insulating substrate while sucking from the opposite side.