JPH01302793A - Circuit board - Google Patents

Abstract

PURPOSE:To effectively utilize a through hole, and realize a small-sized circuit board by arranging a resistor with an inclination on the wall surface of an inverted-cone type through hole formed in an insulative board. CONSTITUTION:An inverted-cone type through hole 12 is formed at a specified position of a ceramic board 11, and a resistor 13 is formed on the wall surface of the hole 12, the surface and the rear of the board 11 of the edge portion of the hole 12. The inclined surface of the cone type hole 12 is effectively utilized. As to the plane view of the resistor 13 part, the projection area becomes smaller as compared with the usual ones. Thereby, a small-sized board 11 can be realized.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention is directed to a circuit board having a resistor, and is particularly applicable to a hybrid integrated circuit.

(Prior Art) Conventionally, as a circuit board used for a hybrid integrated circuit (hybrid IC), one having a structure shown in FIG. 5, for example, is known.

1 in the figure is a ceramic substrate. This board 1 has
A through hole 2 having lands 2a and 2b is formed on the front and back surfaces of the substrate 1. Conductors 3 and 4 are electrically connected to the through holes 2 on the front and back sides of the substrate 1, respectively.
is formed.

Further, on the front side of the substrate 1, a resistor 5 whose resistance value is adjusted by a laser trimmer or a sand trimmer is formed by printing.

Incidentally, recently there has been a demand for high-density packaging of hybrid ICs, but in the case of conventional circuit boards, the resistance value of the resistor 5 is determined by the length and width of the resistor 5, so generally the resistor 5 is occupies a large area (and the circuit board could not be made sufficiently small).

(Problems to be Solved by the Invention) It is an object of the present invention to provide a circuit board that can reduce the area occupied by a resistor in plan view compared to the conventional one by forming it on a wall surface, thereby achieving miniaturization.

[Structure of the Invention] (Means for Solving the Problems) The present invention includes an insulating substrate, an inverted conical through hole formed in the insulating substrate, a resistor formed on the wall of the through hole, The gist is that a conductor connected to the resistor is provided on at least one of the front surface and the back surface of the insulating substrate.

(Function) According to the present invention, by providing the resistor at an angle on the wall surface of the inverted conical through hole provided in the insulating substrate, the through hole can be effectively utilized, and the resistor portion can be formed in a planar manner. When viewed from above, the projected area is smaller than that of the conventional circuit board, and the size of the circuit board can be reduced.

Furthermore, by trimming the inclined resistor portion when adjusting the resistance value, the trimming speed can be increased.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2. Here, FIG. 1 is a sectional view of the circuit board, and FIG. 2 is a plan view thereof.

11 in the figure is a ceramic substrate as an insulating substrate.

An inverted conical through hole 12 is formed in a predetermined position of this substrate 11, and a resistor 13 is formed on the wall surface of this through hole 12 and on the front and back surfaces of the substrate at the edge of this through hole 12. . Note that the through hole 12 can be formed using a mold, a laser beam, or the like. This resistor 13 includes a first resistor portion 14 that extends from the wall surface of the through hole 12 to a land portion on the front surface of the board, and a first resistor portion 14 that extends from the wall surface of the through hole 12 to a land portion on the back surface of the board. It is composed of a resistor portion 15. Here, for the first resistor 13, after placing a resistor material on the land portion on the surface side of the substrate 11,
It is formed by sucking the material through the through hole 12 from the back side of the substrate. Further, the second resistor portion 14
After turning the board 11 upside down and placing the resistor material on the lands on the back side of the board 11, the through holes 12 are inserted from the front side of the board.
by suctioning the material through. Conductors 15 and 16 are connected to the land portions of the first resistor portion 14.

According to the above embodiment, an inverted conical through hole 12 is formed at a predetermined position of the ceramic substrate 11, and the wall surface of the through hole 12 and the edge of the through hole 12 are formed on the substrate surface and back surface. Since it has a structure in which a resistor 13 is formed,
The inclined surface of the conical through hole 12 can be effectively utilized, and the projected area of the resistor 13 can be made smaller compared to the conventional case when viewed in plan, making it possible to downsize the circuit board. In addition, when trimming the resistor 13 to adjust the resistance value, start trimming from a starting position P as shown in FIG. By irradiating the resistor 13 with the laser beam, more of the resistor 13 can be trimmed than in the case where the resistor 13 is irradiated with a laser beam, which is formed entirely in a planar shape, so that the trimming speed can be increased. In FIG. 3, if the actual moving distance of the laser beam is X and the inclination angle of the through hole 12 is θ, then the laser beam has moved by a distance gix/si (90'-θ).

Note that the circuit board according to the present invention is not limited to the structure shown in FIG. For example, as shown in FIG. 4, a conductor 17 connected to the resistor 13 is provided on the front side of the substrate 11, and a conductor 18 connected to the resistor 13 is provided on the back side of the substrate 11. A structure may be adopted in which the front and back conductors 17 and 18 are electrically connected. By adopting this structure, not only can the circuit board be made smaller and the trimming speed improved, but also because the resistor 13 acts as a bridge between the conductors 17 and 18 on the front and back sides of the board 11, The degree of freedom in wiring can be expanded.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to reduce the area occupied by the resistor in plan view compared to the conventional one, thereby achieving miniaturization, improving the trimming speed, and increasing the degree of freedom in wiring. It is possible to provide a circuit board that can perform

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a circuit board according to an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, FIG. 3 is an explanatory diagram of the trimming state of the circuit board, and FIG. FIG. 3 is a cross-sectional view of a circuit board according to another embodiment, FIG. 3 is an explanatory diagram of a trimming state of the same circuit board, and FIG. 5 is a cross-sectional view of a conventional circuit board. 11... Ceramic substrate (insulating substrate), 12... Through hole, 13... Resistor, 15, 16, 17° 18...
·conductor. Applicant's agent Patent attorney Takehiko Suzue Figure 4 Figure 5

Claims (1)

[Claims] an insulating substrate, an inverted conical through hole formed in the insulating substrate, a resistor formed on the wall of the through hole, and a connection to the resistor on at least one of the front and back surfaces of the insulating substrate. A circuit board comprising: a conductor formed as a conductor;