JPH0748411B2 - Function trimming method for hybrid integrated circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention is directed to a hybrid integrated circuit formed by mounting various circuit components including a resistance element on a wiring board, and the function of a resistor for adjusting the circuit characteristics thereof. Regarding trimming method.

[Conventional technology]

In this type of hybrid integrated circuit, desired electrical characteristics may not be obtained due to variations in characteristics of individual elements. In this case, a function trimming method is generally carried out in which the hybrid integrated circuit is assembled and the electrical characteristics of the circuit are measured while adjusting the resistance value of the resistance element so that the circuit characteristic becomes a desired value. .

Such a function trimming method is carried out by directly trimming a resistance element by a trimming device such as a sand trimmer or a laser trimmer in a state where various electronic components are mounted on a wiring board and a hybrid integrated circuit is assembled.

Next, referring to FIGS. 3 and 4, a conventional function trimming method will be described with reference to FIGS. 3 and 4 using a hybrid integrated circuit in which an insulating metal substrate is used as a wiring substrate and a chip resistor is mounted on the substrate as a resistance element. explain. In the figure, 1 is an insulating metal substrate having a structure in which a resin insulating layer 3 is attached to a metal base 2,
Reference numeral 4 is a conductor pattern such as a copper foil formed on the surface of the substrate, and 5 is a chip resistor mounted at a predetermined position on the substrate and soldered to the conductor pattern 4. As is well known, the chip resistor 5 is a thick film resistor on the upper surface of the main body base 51 such as a ceramic material.
52 is attached and electrodes 53 are attached to both ends thereof. The thick film resistor 52 is mounted on the substrate 1 with the upper side facing upward, and in this state, the conductor pattern 4 and the electrode 53 are soldered. 6 is reflow soldered.

Functional trimming for the chip resistor 5 is performed as follows. That is, a trimming start point (chain line A in FIG. 4) is defined on the side edge of the chip resistor 5, the nozzle 71 of the trimming device 7 such as a sand trimmer is initialized by aligning with this point, and sand blasting is performed from here. The thick film resistor 52 is cut by moving and scanning the nozzle 71 in the direction of arrow P to form a notch 54 on the film surface. The trimming amount in this case is performed while monitoring the electrical characteristics of the circuit, and the resistance value is adjusted so that the circuit characteristics of the hybrid integrated circuit have desired values.

[Problems to be Solved by the Invention]

By the way, the above-described conventional function trimming method has the following problems. That is, a wiring board does not cause a problem in a single-sided ceramic board in which a conductor pattern is directly formed on a base plate made of a robust material such as a ceramic board, but an insulating metal board, a copper clad laminated board, or a resin on the ceramic board When a resistance element mounted on a wiring board having an insulating layer having a weak material strength, such as a multilayer wiring board in which a plurality of conductor patterns are formed through insulating layers, is functionally trimmed as described above, At the side portion of the chip resistor 5 which is the trimming start point, the insulating layer 3 on the substrate side is subjected to the trimming action and cut together, and an opening groove is formed at that portion as indicated by the symbol Q, resulting in the wiring substrate. The dielectric strength will be impaired. This problem applies not only to the insulating metal substrate shown in the figure but also to a copper clad laminated substrate such as a resin wiring substrate, which causes a loss in the strength of the substrate itself. On the board, the required dielectric strength cannot be ensured between the conductor patterns, resulting in fatal damage.

The present invention has been made in view of the above points, and its purpose is not to be restricted by the type of wiring board, and to enable functional trimming safely without damaging the wiring board. It is to provide a function trimming method for a hybrid integrated circuit.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, in the method of the present invention, a chip resistor array in which a plurality of chip resistors are arranged in a row in a row is mounted at a mounting location of a resistor element on a wiring board, and one of them is used as a circuit. Connected to the circuit, and the trimming start point of the trimming device is set on the area of the dummy chip resistors that are not connected and are arranged in parallel with the chip resistors connected to the circuit of the chip resistor array, and then connected to the circuit. The trimming is performed on the chip resistor.

[Action]

As in the above method, the trimming start point is set on the area of the chip resistor on the dummy side that is not connected to the circuit with respect to the chip resistor array mounted on the wiring board, and trimming is performed. The main body base of the chip resistor serves as a shield for the wiring substrate located behind it, and the insulating layer of the wiring substrate can be safely protected from the trimming action.

The chip resistor array is obtained by breaking, for example, two chip resistor bodies in series without cutting the chip resistor bodies manufactured by the multi-cavity manufacturing method into individual pieces. Therefore, a general-purpose chip resistor can be used as the chip resistor array, and since it is the same chip resistor, it does not matter which one is connected to the circuit and there is no problem if the orientation is reversed, so mounting is easy. Is.

〔Example〕

FIGS. 1 and 2 show working state diagrams of functional trimming according to an embodiment of the present invention, and the same members corresponding to FIGS. 3 and 4 are designated by the same reference numerals.

That is, according to the present invention, the chip resistor array 50 in which two chip resistors are horizontally arranged without being broken into individual pieces as chip resistors is mounted at a predetermined mounting location on the wiring board 1. The chip resistors lined up on the right side are left as dummy without being connected to the conductor pattern 4,
The chip resistor on the left side is soldered and bonded to the conductor pattern 4 and incorporated in the circuit.

In order to perform the function trimming of the resistance in the assembled state of the circuit, first, the trimming start point of the tip nozzle 71 of the trimming device 7 is set on the surface area of the dummy side chip resistors arranged on the right side as shown by the chain line A, From here, move the nozzle 71 to the arrow P
The thick film resistor 52 is cut from the left chip resistor connected to the circuit by scanning in the direction, and trimming is performed by a necessary amount. At the trimming start point, the chip resistors on the dummy side are simultaneously subjected to the trimming action, but this trimming has no effect on the circuit characteristics of the hybrid integrated circuit. In addition, since the main base 51 itself in the chip resistor area on the dummy side functions as a shield for the insulating layer 3 of the wiring board 1 located behind it, the insulating layer 3 on the wiring board side is not damaged and is safe. Functional trimming can be performed.

Although the illustrated embodiment shows an example in which an insulating metal substrate is adopted as the wiring substrate 1, the present invention is not limited to this, and the wiring substrate is made of resin or another insulating material. Needless to say, the same can be applied to a multi-layered copper-clad laminated board and further to a multi-layered ceramic board.

〔The invention's effect〕

As described above, according to the present invention, a chip resistor array in which a plurality of chip resistors are arranged in a row in a row is mounted on a mounting portion of a resistance element on a wiring board, and one of them is connected to a circuit, And for the chip resistors connected to the circuit after setting the trimming start point of the trimming device on the area of the dummy chip resistors that are not connected and are arranged in parallel to the chip resistors connected to the circuit in the chip resistor array. By performing trimming, the chip resistor on the dummy side in the chip resistor array acts as a shield for the wiring board located behind it, and the insulating layer of the wiring board is used in the function trimming process performed after circuit assembly of the hybrid integrated circuit. The function trimming is safe without damaging the cable and thus without compromising the strength and dielectric strength of the wiring board. Execution can effect can be obtained. Also,
As the chip resistor array, a general-purpose chip resistor can be used instead of a resistor dedicated to function trimming, and since the same chip resistor is used, whichever may be connected to the circuit, the orientation will be reversed. Since there is no problem, it is easy to implement. Since the chip resistor array may be reversed in direction, only the dummy chip resistor at the trimming start point and the chip resistor connected to the circuit are needed, so that no wasted space is required and the space factor is reduced. good.

[Brief description of drawings]

1 and 2 are side views of a main part of a hybrid integrated circuit showing working states of functional trimming according to the method of the present invention, and plan views thereof, FIGS. 3 and 4 are FIGS. 1 and 2, respectively. It is a conventional function trimming work state diagram corresponding to the drawing. In each figure, 1: wiring board, 4: conductor pattern, 50: chip resistor array, 5
1: body base, 52: thick film resistor, 53: electrode, 7: trimming device, 71: nozzle, A: trimming start position, P: trimming scanning direction.

Claims (1)

[Claims] 1. A function trimming method for a hybrid integrated circuit in which a circuit including a resistance element is formed on a wiring board.
A chip resistor array in which a plurality of chip resistors are arranged in a row in a row is mounted at a mounting location of the resistor element on a wiring board, and one of them is connected to a circuit and connected to a circuit of the chip resistor array. Hybrid chip integration, wherein a trimming start point of a trimming device is set on an area of a dummy chip resistor which is not connected and is arranged in parallel with the chip resistor connected to the circuit, and trimming is performed on the chip resistor connected to the circuit. Circuit function trimming method.