JPH0126521B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for adjusting the resistance value of a membrane resistor.
More specifically, the present invention relates to a method of adjusting the resistance value of a microresistance network element formed by a metal vapor deposition film or the like on an insulating substrate such as glass or ceramic.

Metal film resistors have good resistance value stability against changes in ambient temperature, etc., and change over time is small.
It has traditionally been used as a resistance element in important circuits such as electronic equipment. Among these film resistors, those that require resistance value matching are trimmed using a laser processing machine or the like.

FIG. 1 shows a conventional example of a film resistor trimmed by a laser beam machine. Referring to the figure, the film resistor 1 includes a resistance element 3 made of a metal vapor deposited film formed on an insulating substrate 2, and a pair of resistive elements 3 having a low resistance value similarly formed of a metal vapor deposited film on both ends of the resistance element 3. It has electrodes 4, 4. The resistive element 3 has, for example, three notches 5, 6, 7 trimmed by a laser processing machine (not shown).
etc. are formed. Lead wires (not shown) are bonded to the electrodes 4, 4, and the resistance value of the resistance element 3 is read by an external device (not shown) connected to the lead wires. The above-mentioned cuts 5 to 7 are for increasing the resistance value of the resistance element 3, and are generally arranged in a direction perpendicular to the current path connecting the two electrodes 4, 4, as shown in the figure. It is applied to In this case, its position, width, length, etc. are accurately controlled by a laser processing machine, so that the resistance value of the resistance element 3 can be precisely adjusted to a predetermined value.

When forming such a film resistor 1 by photolithography technology or the like, for example, the width W of the resistance element 3 is kept constant, and its length L is set to the resistance value before making the notch, that is, the initial resistance. Conventionally, it has been common practice to set according to the magnitude of the value. In this case, there is no particular problem with a resistor element having a relatively high initial resistance value, but as the initial resistance value decreases, the length dimension L also decreases, so the number of cuts is limited even if they are made. For this reason,
It has been difficult to manufacture an adjustable low-resistance film resistor due to limitations in the adjustment range and adjustment accuracy of the low resistance value. Furthermore, when trimming with a laser beam or the like, thermally altered layers 5' to 7', called so-called heat affected zones, are simultaneously formed around the cuts 5 to 7, but these thermally altered layers Since 5' to 7' do not necessarily maintain an electrically stable state, it is desirable to have a film resistor with fewer thermally altered layers in the vicinity of the current path, such as the dotted line in the figure. Ta.

This invention was made in view of the above points, and its purpose is to easily perform coarse adjustment that changes the resistance value of a film resistor in steps and fine adjustment that changes it little by little, and to It is an object of the present invention to provide a method for adjusting the resistance value of a film resistor that can be trimmed so as to reduce the influence of a deteriorated layer.

Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the accompanying drawings.

First, with reference to FIG. 2, the structure of a membrane resistor to which the resistance value adjustment method according to the present invention is applied will be explained. As shown in FIG. It has a film-like electrode layer 13 formed so as to overlap with each other. In this embodiment, tantalum nitride (Ta ₂ N), for example, is used as the constituent material of the resistance layer 12 formed on the ceramic substrate 11, and its pattern is as shown in FIG. For example, two notches 14, 15 and 20
window holes 16 to 35. Of these, ten window holes 16 to 25 are cut out portions 14.
are arranged at equal intervals on an imaginary straight line A passing through the
Similarly, the ten window holes 26 to 35 are arranged at equal intervals on an imaginary straight line B passing through the notch 15.

For example, nichrome (NiCr)-gold (Au) is used as the constituent material of the electrode layer 13 formed so as to overlap this resistance layer 12, and its pattern is shown in FIG. As shown, the notches 14 and 15 of the resistance layer 12 and each window hole
For example, two notches 36 and 37 and 20 slits 38 to 57 are provided corresponding to positions 6 to 35, respectively. When the resistance layer 12 and the electrode layer 13 are integrally formed on the ceramic substrate 11 by photolithography or the like, a film resistor 10 as shown in FIGS. 1 and 2 is obtained. In this case, it is also possible to form an electrode layer 13 on a ceramic substrate 11 and form a resistance layer 12 in each slit of this electrode layer 13, as shown in FIG.

Next, a method for adjusting the resistance value of the film resistor 10 using a laser beam will be described with reference to FIGS. 3 and 4.

First, a film resistor 10 is placed in a laser processing machine (not shown).
is attached, and the starting position of the laser beam 58 is set within the notches 14 and 36. in this case,
Adjust the intensity and focus of the laser beam in advance. In the embodiment shown in FIGS. 3 and 4, for example, the laser beam 58 is moved from the start position C in the direction shown by the solid line arrow to the position D to cut into the window hole 16, and then the window hole 16 is cut. 17
This is a case where the slit 39 is cut by moving in the direction shown by the dotted line arrow. Since the resistance layer 12 and the electrode layer 13 are integrally formed vertically, the resistance layer 12 is cut along with the slit 39. In this case, the trimming pattern on the slit 39 by the laser beam 58 is circular with an overlapping portion. The resistance value of the resistance layer 12 in each of these slits is defined as r, and the space between the slits is regarded as one electrode portion having an extremely small resistance value, and is designated by reference numerals 61 to 8 as shown in FIG. 5A.
2, the equivalent circuit becomes as shown in FIG. Laser beam 5 in Figure 3 above
When points C and D of No. 8 are shown in FIG. 5, they become as shown. In this case, the resistance R between the electrode parts 61 and 71
1 is a series composite resistance of the resistance r in the slit 38 added in steps by trimming and the resistance r' formed by changing the resistance r in the slit 39 by fine trimming, R1=r+r' It is expressed by the following formula. In addition, in FIG. 6, for example, seven electrode parts are cut along the virtual straight line A from the electrode part 61 to the point E of the electrode part 68,
Next, from this point E, cut for fine adjustment is made in the same manner as above along the slit 45, and assuming that the resistance is r'', the total series combined resistance R1' is R1' = 7 x r + r''. . Furthermore, following the first trimming example, that is, R1=r+r', a cut is made along the imaginary straight line A to the point E, and the second trimming is performed.
As in the trimming example, if a cut for fine adjustment is made along the slit 45 and the resistance is r'', the overall series combined resistance R1'' is R1'' = r + r' + 5 x r + r''. This is easy to understand. Note that, for example, if a potential difference is applied between the electrode parts 61 and 71, the fourth
A current flows along an imaginary current path as shown by the dotted line in the figure and FIG. is completely unrelated. Therefore, according to the present invention, the influence of the thermally altered layer can be reduced.

The above example of adjusting the resistance value is a case where the right half of the film resistor 10, that is, the 10 resistors r in the 10 slits 38 to 47 are combined with the 11 electrode parts 61 to 71. It is clear that the adjustment can be made in the same way when each resistor r in the left half, that is, the ten slits 48 to 57 is combined with the eleven electrode parts 72 to 82.

Furthermore, in FIG. 5A above, this film resistor 1
A notch 84 as shown by the dotted line is made in the center bridging portion 83 of 0 to electrically separate the left and right sides, and if the series combined resistance of the right half is R1 and the series combined resistance of the left half is R2, the result shown in FIG. Two types of combinational circuits as shown in the equivalent circuit can be constructed.
The circuit shown in Figure A is a circuit in which the electrode parts 71 and 72 are connected in common, and the left and right combined resistances R1 and R2 viewed from both ends of the electrode parts 61 and 82 are connected in series. The electrode parts 61 and 82 and the electrode parts 71 and 72 are connected in common, respectively, and the left and right combined resistance R is
1 and R2 are connected in parallel.

As explained in detail above, the twisted film resistor 10
The resistive layer 12 and the electrode layer 13 having slits are layered vertically on the right half and the left half of an insulating substrate 11 made of ceramic or the like, or a photolithography is carried out so that the resistive layer 12 is interposed in the slit. These left and right electrode layers extend toward the center and are bridged. Each of the combined resistances R1 and R2 obtained by the left-side resistance layer and the electrode layer has its resistance value increased in steps by making cuts to break the bridge between the center part and each electrode part. Furthermore, by cutting along the slit, the resistance value can be changed minutely. These left and right combined resistances R1 and R2
can be used individually, but by appropriately connecting the electrode parts in common, the above-mentioned resistors R1,
It is also possible to configure R2 in a series-connected or parallel-connected circuit. Thereby, resistance values can be easily adjusted over a wide range from relatively high resistance to low resistance using the same film resistor.

In the above embodiment, the case where the window holes 16 to 35 etc. are formed in the resistance layer 12 is shown.
These window holes do not necessarily have to be provided. Incidentally, the size of this film resistor 10 is about 1.5 mm in length and width, and is cut out with a cutter or the like from a substrate formed in a matrix shape of several centimeters. It goes without saying that the dimensions of the film resistor 10 can be arbitrarily set depending on the resistance value, economic efficiency, etc.

[Brief explanation of drawings]

Figure 1 is a plan view showing an example of a conventional membrane resistor, Figures 2 to 6 all relate to embodiments of the present invention, Figure 2A is a plan view of the membrane resistor, and Figure 2B is the above-mentioned example. C is a plan view of the resistive layer pattern, D is a plan view of the electrode layer pattern, and E is a modified example of the above A in which the resistive layer is formed in the slit of the electrode layer. 3 is a partial perspective view of cutting into this membrane resistor using a laser beam, 4 is a partial plan view of the same, and 5 and 6 are views of this membrane resistor. An example of a combination for making a cut in a vessel is shown; FIG. 5A is a plan view thereof, and FIG. 5B and FIGS. 6A and 6B are equivalent circuits thereof. In the figure, 10 is a film resistor, 11 is an insulating substrate, 12
13 is a resistive layer, 13 is an electrode layer, 38 to 57 are slits, 58 is a laser beam, and 83 is a bridge portion.

Claims (1)

[Claims] 1. A resistive layer formed on an electrically insulating substrate, a plurality of electrode parts capable of dividing the resistive layer into small pieces having predetermined dividing resistance values, and a plurality of electrode parts formed between these electrode parts. When adjusting the resistance value of a film resistor provided with an electrode layer having a bridging portion by laser trimming, the bridging portion between the arbitrary electrode portions is cut with a laser beam to remove the resistance layer. a coarse adjustment step in which the electrodes are separated into small pieces having a predetermined divided resistance value, and a series current path is formed between the small pieces via the electrode portions to change the resistance value as a whole in a stepwise manner; A method for adjusting a resistance value including a fine adjustment step of finely adjusting the resistance value as a whole by irradiating the resistive layer exposed between portions with a laser beam to remove the resistive layer, During the process, the laser beam is irradiated from one of the electrode portions located on both sides of the resistive layer to the other electrode portion through the resistive layer, and further travels back and forth between the electrodes via the resistive layer. A method for adjusting the resistance value of a film resistor, characterized in that the laser beam is continuously irradiated to a predetermined region.