JPH06338405A - Method for trimming resistor - Google Patents

Abstract

PURPOSE:To provide a trimming method that does not cause current concentration and improves the trimming speed of a resistor. CONSTITUTION:After measuring an initial resistance value of a resistor, the seat resistance of that resistor is calculated, 12-position is determined where the trimming is performed in the direction of the current on the basis of the target resistance value, and the position of the resistor is corrected by using a recognition pattern formed on a substrate. Then, 11-trimming is started that intersects at approx. right angle in the direction of the current from a certain starting point provided on a position which is outside of the corner of the resistor, the trimming is turned to the direction of the current at the point where it reaches the 12-position with continuous state, and the 12-trimming is performed up to the position near other electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistor trimming method.

[0002]

2. Description of the Related Art Conventionally, when a resistor is formed between conductors formed on a substrate such as a hybrid integrated circuit substrate, generally, trimming adjustment is performed to adjust the resistance value of the resistor to a predetermined target value. Is done. In a conventional general trimming method, laser trimming called L cut for forming an L-shaped slit in a resistor is performed.

[0003]

The initial resistance value of the resistor before trimming may be different from the preset resistance value due to variations in film thickness, pattern formation, and the like, which causes the following problems. That is, in the L-cut trimming method, since the L-cut bending point resistance is set to about 80 to 95% of the target resistance value in the trimming program, for example, the initial resistance value is close to the target resistance value. In some bodies, the resistance value reaches the target value before the direction change (turn) of the L-cut trimming is performed, and the resistance value becomes a simple straight cut to cause current concentration. Further, in the case of a resistor whose initial resistance value is considerably lower than the target resistance value, it may reach the electrode before reaching the target resistance value and trimming may not be completed.

Further, in the conventional general trimming method, the above-mentioned problem occurs because the resistor is trimmed while controlling the resistance value of the resistor so as to reach the pre-programmed target resistance value. .
Further, in the conventional trimming method, since the trimming is performed while controlling the resistance value as described above, the trimming speed is slow, and when there are a plurality of resistors on one substrate, or there is a large variation in the resistance value. In such a case, there is a problem that it takes time to trim the resistor and workability is deteriorated.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is a method of trimming a resistor which does not cause current concentration after trimming of the resistor and can improve the trimming speed. Is to provide.

[0006]

[Means for Solving the Problems]
In order to achieve the object, the method of trimming a resistor according to the present invention measures the initial resistance value of the resistor, calculates the sheet resistance of the resistor, and trims in the current direction based on the target resistance value. ₂ positions are defined, l ₁ trimming, which is substantially orthogonal to the current direction, is started from a start point provided near one of the electrodes and outside the edge of the resistor, and the continuous state is maintained at the point where the l ₂ position is reached. It is characterized in that it is turned in the current direction and l ₂ trimming is performed up to the vicinity of the other electrode.

[0007]

In the above-described resistor trimming method, since trimming is performed without controlling the target resistance value, even if there is a variation in the resistance value of the resistor, l ₂ for trimming in the current direction is always between the electrodes. Since it is formed (exists) to the full, current concentration hardly occurs.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of trimming a resistor according to the present invention will be described below with reference to the embodiments shown in FIGS. FIG. 1 is a plan view showing a resistor, and FIG. 2 is a plan view when the resistor is trimmed.

The resistor (1) is an insulating substrate (not shown).
It is formed of a conductive material having a predetermined resistance value between the conductive paths formed above. As the insulating substrate, for example, an insulating-treated aluminum substrate, a ceramics substrate,
A glass epoxy substrate is used, and in this embodiment, the resistor (1) is formed on an aluminum substrate. An insulating metal oxide film is formed on the surface of the aluminum substrate by anodic oxidation, and an insulating layer such as an epoxy resin is provided on the metal oxide film. The insulating layer is for insulating and adhering the aluminum substrate and the copper foil,
By etching the bonded copper foil into a predetermined pattern, a conductive path (2) having a desired shape is formed on the insulating layer. Although not disclosed in the figure, chip capacitors, transistors, LSI elements and circuit elements such as resistors (1) are connected on the conductive paths (2).

As the resistor (1), a carbon resistor or a nickel plating resistor is used, and in this embodiment, a carbon resistor is used. The carbon resistance is, for example, epoxy resin 100, carbon 8, inorganic filler 3
A carbon resin paste having a composition of 0 to 100 and an organic solvent 100 is screen-printed between the conductive paths (2) and baked to form the carbon resin paste. An Ag paste layer (not shown) is formed on the conductive path (2) connected to the resistor (1).

The trimming method of the present invention is performed based on the flowchart shown in FIG. First, a probe or the like is brought into contact with both electrodes of the conductive path (2) to measure the initial resistance value of the resistor (1). Next, after measuring the initial resistance value, the sheet resistance R _S of the resistor (1) is calculated. Resistor (1)
The sheet resistance R _S of No. 1 is originally determined by the material used, but an error in film thickness and bleeding occurs due to the printing accuracy of screen printing. Actually, the sheet resistance R _S is different before and after screen printing. There is. Since the present invention the sheet resistance R _S is a very important value, dare, sheet resistance R _S of the resistor after the screen printing (1)
Is calculated.

The sheet resistance R _S is obtained by the following equation.

[0013]

[Equation 1]

After the sheet resistance R _S is calculated, the l ₂ position W _x for trimming in the current direction of the L-shaped cut is calculated. W
_x is _calculated by the following formula.

[0015]

[Equation 2]

When the l ₂ position W _x for trimming in the current direction is calculated, the trimming distance l _{1 which} is orthogonal to the current direction starting from the start point is obtained. l ₁ is W−W _x +
Inevitably determined by A. The start point is the position where the laser trimming is started, and this point is separated from the edge of the resistor (1) by a certain distance A and is set at a position near one conductive path (2).

After calculating W _x and l ₁ , laser trimming is performed by substituting the data into coordinates. In the present invention, the position of the resistor (1) is corrected immediately before laser trimming, and then trimming is performed. To do. The printing resistor (1)
As described above, because it is performed by screen printing, due to the position shift of the stencil for screen printing,
It is difficult to print accurately between pre-designed conductive paths, and the resistor (1) may be slightly displaced during the manufacturing process, for example, as shown in FIG. Therefore, in the present invention, when the resistor (1) is formed by screen printing, the recognition pattern (3) is formed at a predetermined position on the substrate. Then, by using this pattern (3), the resistor (1)
After the position correction is performed, the resistor (1) is trimmed to the target resistance value. That is, since the resistor (1) and the recognition pattern (3) are formed on the substrate with the same stencil, if the resistors (1) are misaligned and printed, it is The recognition pattern (3) is also displaced at the same time.

When trimming the resistance value of the resistor (1) to the target resistance value, in the present invention, since the trimming position and length of l ₁ and l ₂ are already determined, l ₁ trimming is performed from the start point. And when the position reaches the l ₂ position W _x , the current is turned in the continuous direction and l ₂
Trimming is done automatically. What is important here is that even if the resistor (1) is displaced,
As described above, since the position correction is performed using the recognition pattern (3) immediately before the trimming, the start point for starting the trimming is always separated from the edge of the resistor (1) by the constant distance A regardless of the positional deviation. The trimming distance l ₁ from the start point does not change due to the displacement of the resistor (1).

Further, in the present invention, since the position and distance to be trimmed are already calculated, the trimming of l ₁ and l ₂ is automatically performed without controlling the target resistance value during trimming. Therefore, the end point of l ₂ trimming is set to always end near the other conductive path irrespective of variations in the resistance value of the resistor, so that current concentration does not occur. More specifically, in the trimming method of the present invention, the distances and positions of the trimmings l ₁ and l ₂ are preset based on the initial resistance value and the sheet resistance R _S , and the resistor (1 ) Can be trimmed to a predetermined target resistance value.

After performing the L-shaped cut trimming,
The resistance value of the resistor (1) is measured, and if it is within the allowable range of the target resistance value, the trimming ends. In the present embodiment, the position correction of the resistor (1) is performed by forming the recognition pattern (3) when the resistor (1) is formed and using the recognition pattern (3), but as another method, an optical sensor is used. May be used by using the luminous intensity of the resistor (1) and its surroundings.

[0021]

As described in detail above, according to the present invention,
Sheet resistance R is measured from the initial resistance value by measuring the initial resistance value.
Even if there is a variation in the resistance value of the resistor, trimming is performed by calculating _S , determining the turn position of L ₁ of L cut, correcting the position of the resistor, and then performing trimming.
_Since the end point of ₂ always ends near the electrode, no current concentration occurs.

Further, according to the present invention, by trimming after the position of the resistor is corrected, it is possible to surely perform trimming to the target resistance value even when the resistor is printed with a deviation. Further, according to the present invention, the resistance value of the resistor can be trimmed to the target resistance value by one trimming without controlling the target resistance value, and the trimming speed can be remarkably increased.

[Brief description of drawings]

FIG. 1 is a plan view showing a resistor.

FIG. 2 is a plan view showing a trimmed resistor.

FIG. 3 is a flowchart showing a trimming method of the present invention.

[Explanation of symbols]

 (1) Resistor (2) Conductive path (3) Recognition pattern

Claims (2)

[Claims] 1. A method of trimming a resistor in which a resistor is formed between electrodes formed on an insulating substrate and the resistor is trimmed to a predetermined resistance value after measuring an initial resistance value of the resistor. , The sheet resistance of the resistor is calculated, the l ₂ position to be trimmed in the current direction is determined based on the target resistance value, and the position of the resistor is corrected, and then, in the vicinity of one electrode and in the vicinity of the resistor. L _{1 which} is substantially orthogonal to the current direction from the start point provided at
A method of trimming a resistor, characterized by starting trimming and turning in the direction of current at the point of reaching the l ₂ position to perform l ₂ trimming to the vicinity of the other electrode. 2. A resistor trimming method in which a resistor is formed between electrodes formed on an insulating substrate, and the resistor is L-shaped cut trimmed to a predetermined resistance value, wherein an initial resistance value of the resistor is After the measurement, the sheet resistance of the resistor is calculated, the l ₂ position for trimming in the current direction is determined based on the target resistance value, and the position of the resistor is corrected using the recognition pattern formed on the substrate. Then, l ₁ trimming, which is substantially orthogonal to the current direction, is started from a constant start point provided near one of the electrodes and outside the edge of the resistor, and a continuous state is reached at the point where the l ₂ position is reached. Turn to the current direction as it is and
_2. A trimming method for a resistor, which is characterized by performing trimming.