JPH04217389A - Thick film multilayer circuit substrate and manufacture thereof - Google Patents

Abstract

PURPOSE:To make conductor patterns into a multilayer by preventing generation of unevenness in making circuit substrates having through holes multilayered while preventing residual air inside the through holes. CONSTITUTION:The through holes 4a, 4b formed in the circuit substrates (2) is filled with an insulator (resist 8) so as to level aforesaid circuit substrates followed by forming the insulating layers (resists 12a, 12b) are formed on the conductor patterns (first conductor patterns 6a, 6b, 6c, 6d) on aforesaid circuit substrates, and thereon conductor patterns (14a, 14b, 14c, 14d) are formed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thick film multilayer circuit board used for multilayering a circuit board having through holes formed therein, and a method for manufacturing the same.

0002

2. Description of the Related Art A circuit board made of an insulating material such as alumina has various circuit patterns formed on its front and back surfaces, and a plurality of electronic components are mounted thereon. In such circuit boards, conductor connection through through holes is performed as a technique for electrically connecting circuit patterns between the front and back surfaces.

[0003] Furthermore, multilayer circuit boards in which circuit boards on which independent circuit patterns are formed are laminated have also been put into practical use. Such multilayer circuit boards make it possible to make complex circuits more compact and to mount electronic components at high density, and there are great expectations for the realization of complex functional circuits.

0004

[Problems to be Solved by the Invention] By the way, when circuit boards with through holes formed in them are laminated, the through holes formed in the circuit boards cause unevenness in the laminated insulating layers and conductor patterns. prevent the development of Furthermore, if air remains in the through-holes confined by the insulating layer, the expansion and contraction of the air may cause separation from the conductor pattern, reducing the reliability of the circuit board.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a thick film multilayer circuit board and a method for manufacturing the same, which prevents the occurrence of unevenness in multilayering of a circuit board in which through holes are formed, and also prevents air from remaining in the through holes. With the goal.

[0006]

[Means for Solving the Problems] That is, in the thick film multilayer circuit board of the present invention, the first conductor patterns (6a, 6b, 6c, 6d) formed on the front and back surfaces are the through holes (4a, 4).
b) and the insulator (resist 8) filled in the through hole of this circuit board (2) connected via
), an insulating layer (resist 12a, 12b) formed covering the conductive pattern, and a second conductive pattern (14a, 14b, 14c, 14d) formed on this insulating layer.
).

The method for manufacturing a thick film multilayer circuit board of the present invention also provides a first conductor pattern (6a) formed on the front and back surfaces.
, 6b, 6c, 6d) are connected through the through-holes (4a, 4b) through the through-holes of the circuit board (2) are filled with an insulating material (resist 8), and then the insulating material covering the surface of the circuit board is filled. forming a layer (resist 12a, 12b);
A second conductor pattern (14a, 14b) is formed on this insulating layer.
, 14c, 14d).

[0008]

[Function] In addition, in the thick film multilayer circuit board of the present invention, the through holes are filled with an insulator, so that no recesses are formed due to the through holes, and the surface of the circuit board is flattened.
Multi-layering of conductor patterns and insulating layers is possible, and circuit patterns on the front and back sides of the circuit board can be electrically connected through through holes, realizing multi-layering on both sides.

Further, in the method of manufacturing a thick film multilayer circuit board of the present invention, the through holes formed in the circuit board are filled with an insulating material, and the through holes are hidden by the insulating material. An insulating layer is formed on the insulating layer, and a second insulating layer is formed on the insulating layer.
Since the conductor patterns are stacked, the conductor patterns are flattened, and the air in the through holes is removed by the insulator, resulting in a flat thick film multilayer circuit board.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the thick film multilayer circuit board of the present invention, and FIGS. 2 and 3 show an embodiment of the method of manufacturing the thick film multilayer circuit board of the present invention. As shown in FIG. 2(A), this thick film multilayer circuit board uses a circuit board 2 made of an insulating material such as alumina or ceramic. Through holes 4a and 4b are formed to provide electrical continuity between the circuits to be connected.

The front and back surfaces of this circuit board 2 are as shown in FIG.
) and as shown in FIG. 4, first conductor patterns 6a, 6b, 6c, and 6d are formed by printing conductor paste, etc., and each conductor pattern 6a to 6d has a through hole 4a, 4b.
connected through the inner wall of the In the case of this embodiment, electrical connection between two circuits is made using each through hole 4a, 4b.

[0012] In each through hole 4a, 4b,
As shown in FIG. 2C, a resist 8 is filled as an insulating material by printing or using a dispenser.
The through holes 4a and 4b are filled with the conductor patterns 6a to 6d so that they are flush with each other.

After filling each of the through holes 4a and 4b with the resist 8, the portions exposed from the conductor patterns 6a to 6d on the front and back sides of the circuit board 2 are filled with the resist 8 shown in FIG. 2(D).
As shown in FIG. 1, resists 10a and 10b are installed by printing, and the resists 10a and 10b are set to have the same thickness as the conductor patterns 6a to 6d. Therefore, each through hole 4a, 4b is filled with resist 8, and the parts other than the conductive patterns 6a to 6d are covered with resist 10a, 10b, so that the circuit board 2
The front and back surfaces form flat surfaces that are ideal for multilayering.

The front and back surfaces of this circuit board 2 are shown in (E) in FIG.
), resists 12a, 12 as insulating layers
b are formed uniformly, and insulation of each conductor pattern 6a to 6d is achieved.

[0015] On the surfaces of these resists 12a and 12b,
As shown in FIG. 3(F), second conductor patterns 14a, 14b, 14c, 14d for forming a specific circuit
are selectively formed, and as shown in FIG. 3(G), resists 16a and 16b as insulating layers are formed with the same thickness as the conductor patterns 14a to 14d, as shown in FIG. 3(G). formed, conductor patterns 14a to 14
As a result of compensating for the unevenness between d and the resists 12a and 12b, the circuit board 2 can be planarized. Although not shown, the conductor patterns 14a to 14d and the conductor patterns 6a to 6d formed directly on the circuit board 2 are electrically connected as necessary, and the connection is made by a conductor pattern penetrating through the resists 12a and 12b. be exposed.

As shown in FIG. 1, a resist 18 is formed on the surface of the multilayered circuit board 2 as an insulating layer.
a and 18b are formed by printing, and the outer surface of the circuit board 2 is electrically insulated.

As described above, the through holes 4a and 4b are filled with an insulator to flatten the circuit board 2, and the air inside the through holes 4a and 4b is removed by the insulator. Resist 12a, 12b, conductor patterns 14a to 14d, etc. are laminated to form a multilayered circuit.

Moreover, the unevenness caused by the through holes 4a and 4b is compensated by the resist 8, and the circuit board 2 is flattened, so that each of the conductor patterns 14a to 14d has a flat plate shape, and the precision of pattern printing is improved, making it reliable. A circuit pattern with high quality can be obtained.

In the embodiment, a case was explained in which two layers each, that is, four layers of circuit patterns were formed on the front and back sides of the circuit board, but since the circuit board is flattened, a multilayer pattern of five or more layers is explained. The thick film multilayer circuit board of the present invention is not limited to the four-layer circuit board of the embodiment.

[0020]

[Effects of the Invention] According to the thick film multilayer circuit board of the present invention,
Since the circuit board is flattened by filling the through holes with an insulator, the thickness of the circuit board does not change partially due to the through holes, and the number of stacked layers can be increased by flattening. Since circuit patterns on the front and back sides of the circuit board can be connected through through holes in addition to multilayering, it is possible to provide a thick film multilayer circuit board in which the front and back sides are multilayered.

Further, according to the method for manufacturing a thick film multilayer circuit board of the present invention, after filling the circuit board in which through holes are formed with an insulating material, an insulating layer is formed, and a conductive pattern is formed on the insulating layer. As a result, unevenness caused by through holes can be prevented and flattened, the number of laminated layers of insulating layers and conductor patterns can be increased, and air in through holes can be eliminated by filling with insulating material, resulting in higher density and reliability. You can increase your sexuality.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a thick film multilayer circuit board of the present invention.

FIG. 2 is a sectional view showing an embodiment of the method for manufacturing a thick film multilayer circuit board of the present invention.

FIG. 3 is a sectional view showing an embodiment of the method for manufacturing a thick film multilayer circuit board of the present invention.

4 is a partial perspective view showing a circuit board in one embodiment of the method for manufacturing the thick film multilayer circuit board shown in FIG. 2; FIG.

[Explanation of symbols]

Claims (2)

[Claims] 1. A circuit board to which a first conductive pattern formed on the front and back surfaces is connected via a through hole, an insulating material filled in the through hole of this circuit board, and a first conductive pattern covering the conductive pattern. A thick film multilayer circuit board comprising: an insulating layer; and a second conductor pattern formed on the insulating layer. 2. After filling the through holes of the circuit board to which the first conductor patterns formed on the front and back surfaces are connected through the through holes with an insulator, forming an insulating layer covering the front surface of the circuit board, A method for manufacturing a thick film multilayer circuit board, comprising forming a second conductor pattern on the insulating layer.