JPS6150356A - Adjustment for impedance of impedance parts - Google Patents

Abstract

PURPOSE:To adjust the resistivity of a mounting resistance parts without flawing a pattern to pass under the resistance parts by a method wherein parts of the resistance film made of carbon and so forth are removed, parts of the ceramic part under the resistance film are made to expose, a trimming starting point is set at either of the exposed parts and a laser trimming is started from the point. CONSTITUTION:The carbon resistance film 12 of a chip parts 1 is removed both end parts thereof in the rectangular direction to a parts electrode 11 over almost the whole thereof and parts of a ceramic parts 13 are made to expose. A trimming starting point 6 is set at the prescribed position in the ceramic part 13 and a laser trimming is started from this point 6. By this constitution, the laser trimming can be performed without flawing a pattern 3 to pass under the chip parts or without cutting the pattern 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for adjusting the impedance value of an impedance component mounted on a printed circuit board and including a conductive film and an insulating plate.

[Conventional technology]

Conventionally, semi-fixed resistors have been used to adjust the resistance value of resistors mounted on printed circuit boards. However, lead-type semi-fixed resistors are not suitable for high-density mounting, and chip-type semi-fixed resistors are more expensive and less reliable than lead-type resistors because the flux during delag soldering causes contact failure. was. Therefore, instead of such conventional semi-fixed resistors, a method was devised in which a component in which a carbon resistive film is coated on an insulating plate is used, and the resistance value is adjusted by rimming or cutting it using a laser beam. .

[Problem that the invention seeks to solve]

FIG. 5 shows the results of laser trimming when a conventional chip resistor component is used. FIG. 5A is a plan view, and FIG. 5B is a cross-sectional view along x-xHve of FIG. In these figures, (11 indicates the chip component as a whole, (
11) is the electrode of the chip component, (12) is the Kergan resistive film, (13) is the insulating plate such as ceramic, (2) is the land and lean of the chip component, and (3) is the hole passing under the chip component. 9 turns, (4) is the trimming φ cut part, (5)
indicates a printed circuit board. Special K, (41) in Figure 1A is
Near the start of the trimming cut (4), the lower pattern (3) shows the section cut by the laser m-beam. In this way, in laser trimming after mounting, it is inevitable that the laser
There was a problem that the beam also cut the pattern (3) below. ``The first method that can be considered to prevent this is to partially increase the width of the lower mother turn (3).

This is shown by the dotted line in FIG. 5A. The next possibility is to lay the lower pattern (31 horizontally) as shown in Figure 6. Also, as shown in Figure 7, the lower pattern (31) or the turn (
A method of dividing 3) into two patterns (31) and (32) can also be considered. However, since all of these methods change the force of the ie-turn, the design of the ie-turn becomes complicated.

Therefore, the present invention provides a method for adjusting the resistance value of a resistor component mounted on a printed circuit board by leaving the 1,000 turns as they are and performing laser m-trimming so as not to damage the 1,000 turns. Main purpose.

However, the present invention can also be applied to other impedance components in addition to resistive components, as will be described later.

[Means for solving problems]

The present invention uses a resistor component in which a portion of the resistive film such as carbon, including the trimming start point, is removed to expose the ceramic portion underneath. Laser trimming is performed by setting a trimming start point in the exposed portion, and the trimming is completed when the circuit including the resistor component exhibits a predetermined characteristic (for example, current) value.

[Effect]

Laser trimming is started from the trimming start position of the exposed ceramic portion, and while the resistance value of the resistor is measured directly or indirectly, trimming is stopped when a predetermined value is reached. Therefore, the resistance value of the mounted resistor component can be adjusted without damaging the pattern passing under the resistor component.

〔Example〕

An embodiment of the method for adjusting the impedance of an impedance component according to the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing a chip component in which the resistance value of a resistor is adjusted according to the present invention. In this figure, the carbon resistance film (12) of the chip component (1) is connected to the component electrode (11).
) and both end portions in the direction perpendicular to it have been almost completely removed to expose the ceramic portion (13). A trimming start point (6) is set at a predetermined position within this ceramic portion (13), and a trimming cut portion from which laser trimming is started from this point is shown. As a device for performing such trimming, various devices can be considered.

FIG. 2 is a schematic diagram showing an example of an apparatus used in the method of the present invention. In this figure, 00) is a laser light source,
(111 is a movable table on which the printed circuit board (5) is placed, a'aVi is a moving means such as a motor, 131 is a measuring device that shows the characteristics of the circuit including the chip component (1), o4)
is a video camera, and (+51 is a movement control circuit).

Now, consider a case where the video camera I and the movement control circuit O9 are not provided. First, emit visible light from the auxiliary light source built into the laser light source (101) so that a spot is generated at the same point as the laser beam projection point on the printed circuit board.
Move D in the X and Y directions to align the above ceramic part (la) of the spora) K chip component (1) K set trimming star) A (61. To make it easier to see, mark the trimming start point ( 6) It is best to mark K appropriately.

After that, start trimming and perform trimming by moving the laser light source 0α or platform 0υ until the measuring device (131 shows a predetermined value), and then stop the laser light source 001 or gold metal when it shows the predetermined value and start trimming. finish. Since it is easier to move the table 01) in the X and Y directions using the moving means 0z as described above than in known techniques, a detailed explanation will be omitted. Although this method uses the human eye to align the laser projection point and the trimming start point, this can also be done with a video camera and a movement control circuit a9.

That is, for example, the camera 0 is fixed so that the projection point of the laser beam onto the printed circuit board is at the center of the camera imaging surface, and a video signal indicating a predetermined trimming start point stored in advance is sent to the movement control circuit +151. The moving means 07J is controlled by the difference signal in the X and Y directions with respect to the starting point obtained by comparing this signal with the video signal obtained from the camera 0.

FIG. 3 is a plan view showing another example of a chip component that can be used in the present invention. This example can be used for parts whose trimming direction or mounting direction is constant. FIG. 4 is a plan view showing still another example of a chip component that can be used in the present invention. In this example, the exposed area of the ceramic portion (13) is reduced to serve as a mark indicating the trimming start point. This allows the camera 041 to recognize this ceramic portion as a trimming start point. In addition, this example is similar to the example in Figure 1.
Similarly, it can be used regardless of the trimming or mounting orientation.

The above explanation has been given using a chip component having a carbon resistive film as an example, but the present invention can also be applied to impedance components such as capacitors and inductors as long as the component includes a conductive L, film and an insulating plate. be. In other words, in a capacitor that has a conductive film as a plate and an insulating plate as a dielectric, the capacitance can be adjusted by trimming at least one plate. It is sufficient to set a trimming start point on a part of the exposed insulation board. Furthermore, inductors can be considered in exactly the same way as resistors.

Therefore, in the present FJIJ, the conductive film refers to the resistive film in the case of a resistive component, and refers to the electrode plate in the case of a capacitor component.

〔Effect of the invention〕

According to the present invention, when adjusting the impedance value of an impedance component mounted on a printed circuit board, laser trimming can be performed without damaging or cutting a pattern passing under the component. Therefore, in the case of resistance components, it is easy to use K-chip components (in place of conventional semi-fixed resistance components), which enables high-density packaging and cost reduction, and improves reliability. The same applies to other impedance components.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a chip resistance component whose resistance value has been adjusted according to the present invention, FIG. 2 is a schematic diagram showing an example of a device used in the present invention, and FIG. FIG. 4 is a plan view showing another example of the chip component used in the present invention; FIG. 5 is a diagram showing the laser trimming result when conventional chip components are used;
FIG. 6 is a plan view showing an example of a method of not damaging the pattern below the chip component, and FIG. 7 is a plan view showing another example of a method of preventing damage to the bottom pattern. (])...Resistance (impedance) parts, (12)
...Resistive (conductive) film, (13)...Insulating plate, (6)...
...Trimming start point.

Claims (1)

[Claims] In an impedance adjustment method for an impedance component, in which the impedance value is adjusted by trimming a part of the conductive film of the impedance component including a conductive film and an insulating plate with a laser beam, a portion of the conductive film that includes a predetermined trimming start point. An impedance component characterized in that using a component in which a part of the insulating plate is exposed by removing the component, trimming is started from this trimming start point, and trimming is stopped when the impedance component shows a predetermined impedance value. impedance adjustment method.