JP2009231358A - Thick-film resistor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thick-film resistor that dispenses with trimming in a manufacturing process of the thick-film resistor, secures precision in a final resistance value, and has a small amount of current noise in actual use. <P>SOLUTION: On an insulating substrate 101, a resistance wire 301 made of a thick-film resistor and a plurality of conductors 201, 202 selectable as an electrode of the resistance wire 301 are formed. The plurality of conductors 201, 202 are connected to different parts on the resistance wire 301 to allow the resistance value of the resistance wire 301 to be adjusted by conductor selection. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resistance wire made of a thick film resistor and a thick film resistor having an electrode thereof.

  A thick film resistor is generally used as a high voltage dividing resistor in a high voltage power source / constant current power source of a charged particle beam apparatus such as an electron microscope. The resistance paste, which is the main material of the resistor, is basically composed of particles having a particle size of several microns and a bonding material for bonding them. It is considered that the electrical conduction through the contact points of these granular materials is the basis of the characteristic that a resistor using a thick film resistor produces a high resistance value. Resistors using thick film resistors are more accurate than winding resistors and metal film resistors, such as variations in the final resistance value due to the resistance paste material and firing conditions, and the amount of noise under actual use conditions. On the other hand, it is possible to realize a small-sized resistor having a high resistance value that cannot be realized in principle by the above two types of resistors.

  Thick film resistors are roughly classified into two types: round bar type and flat plate type. In general, round bar type is on the surface of the cylinder of the insulating rod, and flat plate type is on one side of the insulating substrate. The resistive paste material forms a wiring pattern. Regardless of the shape of the resistor, the resistivity (material) of the paste material to be used, the material and quantity of the additive, the firing conditions, and the geometric size of the wire material thickness, width and length after firing the paste material are examined. However, it is designed to obtain a predetermined resistance value.

  However, since it is affected by various conditions as described above, it is difficult to obtain a final resistance value as designed only by firing the wiring pattern. For this reason, a process is required in which the wiring pattern is directly processed after firing to match the final resistance value. This process is collectively called trimming. In the round bar type, the final resistance value is obtained while scoring the paste material fired on the side of the cylinder with a file like a spiral. The final resistance value is controlled by cutting or deleting the portion. For this, a method of cutting by laser or sand blasting is generally used.

  Since the above-described trimming process is performed after the resistance pattern is baked, it is directly related to variations in the final resistance value, an increase in current noise during actual use, and the like. For this reason, various studies have been made on trimming from the viewpoint of ensuring the accuracy of the final resistance value and improving current noise during actual use. For example, L-shaped and U-shaped trimming processes (Patent Documents 1 and 2), a method of performing trimming process termination outside the resistance pattern (Patent Document 3), and an annealing and auxiliary re-trimming method after trimming process (Patent Document 4).

  As described above, for thick film resistors, the final resistance value and its accuracy, the current noise level during actual use, etc. are comprehensively examined, and the wiring pattern design and resistance paste agent selection (additives) Selection of resistivity including mixing), baking, and trimming.

Japanese Patent Laid-Open No. 06-37252 JP 09-97707 A JP 2002-8902 A Japanese Patent Laid-Open No. 11-150011

  Resistors made of resistive paste are stable with the least amount of current noise when the state immediately after firing is maintained. However, as described above, trimming after firing is an indispensable process for obtaining a predetermined final resistance value. The outline and problems of the trimming method of the flat plate resistor to which the present invention is applied will be described below.

  The laser trimming method irradiates a trimming area designed in advance while measuring the resistance value between both electrodes of the resistor, evaporates the resistor by local heating, and the wiring pattern until a predetermined resistance value is reached. This is a method of performing cutting / deleting. Laser irradiation can be performed with high accuracy and non-contact on the resistor body, and is a relatively simple method. However, the local heating of the irradiated portion and the rapid temperature drop at the end of the irradiation cause the generation of microcracks in the resistor, thermal distortion of the insulating substrate, and the like. And the increase of the internal stress accompanying this causes a secular change of resistance value, an increase of current noise during actual use, and the like.

  On the other hand, the sandblast trimming method is a method of physically cutting the thick film resistor by spraying abrasive grains such as alumina from a nozzle. Compared with the laser trimming method, there is an advantage that there is no generation of microcracks due to local overheating or thermal distortion on the insulating substrate, and an increase in current noise is suppressed. However, since processing accuracy is limited by the nozzle diameter, accurate trimming becomes difficult as the cutting portion in the resistance pattern becomes thinner.

  As described above, the existence of the trimming process in the manufacture of the thick film resistor is a constraint in achieving the accuracy of the final resistance value of the thick film resistor and improving / decreasing the current noise during actual use. .

  An object of the present invention is to provide a thick film resistor that does not require trimming in the manufacturing process of the thick film resistor, can ensure the accuracy of the final resistance value, and has less current noise during actual use.

  The thick film resistor according to the present invention basically has the following characteristics. That is, a resistance line made of a thick film resistor and a plurality of conductors that can be selected as electrodes of the resistance line are formed on the insulating substrate. The plurality of conductors are connected to different portions on the resistance wire so that the resistance value of the resistance wire can be adjusted by selection of these conductors.

  According to the present invention, it is possible to provide a thick film resistor that can accurately obtain a predetermined final resistance value without performing trimming processing that adversely affects current noise during actual use and that has excellent noise characteristics. it can.

  A thick film resistor using a resistance paste material is stable with the least amount of current noise immediately after firing. However, thick film resistors are affected by various conditions such as paste material mixing conditions, additive material and quantity, and firing conditions. Is difficult to get. For this reason, the conventional thick film resistor always requires a trimming process.

  There are two main trimming methods: laser trimming and sandblast trimming. As described above, processing after firing the wiring pattern ensures accuracy of the final resistance value of the thick film resistor and improves current noise during actual use. It is a constraint in achieving. Therefore, in the present invention, a plurality of conductors that can be selected as electrodes of resistance wires are disposed on an insulating substrate on which resistance wires (thick film resistors) are formed. Further, the plurality of conductors are connected to different portions on the resistance line so that the resistance value of the resistance line can be adjusted by selection of these conductors. The necessary resistance value is ensured by selecting a pair of any one of the plurality of conductors. As a result, a thick film resistor with little current noise during actual use can be obtained without performing trimming.

  FIG. 1 is a schematic diagram of a thick film resistor for explaining the most basic idea of the present invention. On an insulating substrate (for example, ceramics such as alumina) 101, a pair of termination conductors 201 that can be selected as electrodes, a resistance wire 301 made of a thick film resistor that connects the termination conductors 201, and a plurality of electrodes that can be selected as electrodes An intermediate conductor 202 is disposed, and different portions of the resistance wire 301 are connected to each intermediate conductor 202 via a wiring 302. The resistance value R401 can be changed by changing the combination of a set of electrodes selected from all the electrodes.

  FIG. 2 is a schematic diagram for explaining a method for increasing the selection range of the resistance value R and its degree of freedom in the thick film resistor. The thick film resistor shown in FIG. 2 has the same configuration as that of the thick film resistor of FIG. 1, but the connection position of the resistance wire 301 and each wiring 302 is geometrical in the length of the resistance wire 301. It is designed to be different. Furthermore, each wiring 302 has not only a geometrical size such as a length and a width, but also a resistance value R having a large selection range and a freedom by making the material constituting the wiring different from the resistance wire 301. Can give a degree. Further, a part of the wiring 302 is a different kind of wiring 303 whose geometric size or material is different from that of the wiring 302, so that a larger selection range and degree of freedom can be secured by the resistance value R401.

  FIG. 3 is a schematic diagram for explaining a method of increasing the accuracy of the resistance value R to be selected in the thick film resistor. The thick film resistor shown in FIG. 3 is provided with a lead wire electrode 203 as an electrode for connecting the lead wire 102 for connecting the thick film resistor and an external element in the thick film resistor of FIG. Is. The lead wire electrode 203 is connected to the terminal conductor 201 and the intermediate conductor 202 by the first bonding wire 305 by means such as wire bonding. At the time of connection by the first bonding line 305, parallel wiring can be realized by selecting a plurality of intermediate conductors 202 (upper part in FIG. 3), and the selection accuracy of the resistance value R can be improved.

  FIG. 4 is a schematic diagram showing a method of further increasing the selection accuracy of the resistance value R in the thick film resistor. The thick film resistor shown in FIG. 4 is a thick film resistor having the lead wire electrode 203 as shown in FIG. 3, and is connected between the terminal conductor 201 and the intermediate conductor 202 and the lead wire electrode 203. An electrode 204 is provided. In this thick film resistor, the termination conductor 201 and the single or plural intermediate conductors 202 and the relay electrode 204 are connected by the first bonding wire 305, and the relay electrode 204 and the lead wire electrode 203 are also single. Alternatively, they are connected by a plurality of second bonding lines 306. At this time, if the resistance value of the second bonding line 306 cannot be ignored due to the geometric shape of the second bonding line 306 or the type of the wire, the number of the second bonding lines 306 and the wiring length can be adjusted to adjust the final value. It is possible to increase the accuracy of the resistance value R.

  FIG. 5 shows that in the thick film resistor, the resistance wire 301 forms a ninety-nine fold pattern to ensure a sufficient wire length, and the intermediate conductor 202 is connected to each bent portion 105. This is an example in which a wiring 302 is connected. Although not shown in the figure, the wiring 302 is changed to a different type wiring 303 having a different material, line width, thickness, etc. from the resistance wire 301 as shown in FIG. 2 or FIG. It is possible to increase the adjustment range of the resistance value R between the electrodes obtained after selection.

  FIG. 6 shows the thick film resistor shown in FIG. 5, in which the length from the bent portion 105 to the next bent portion 105 of the resistance wire 301 forming the ninety-nine fold changes stepwise from the terminal conductor 201 side. This is an example of the case. The intermediate conductor 202 is connected to the bent portion 105 as in FIG. 5, but the degree of change in the resistance value obtained after selecting a set of electrodes is changed by changing the length between the bent portions 105. it can. The degree of change also depends on how the ninety-nine folded portions 105 are arranged as shown separately on the left and right in FIG. 6, and is not limited to the illustration. Further, although not shown in the figure, as in the example of FIG. 5, the wiring 302 connecting the bent portion 105 and the intermediate conductor 202 is different from the resistance wire 301 in material, line width, thickness, and the like. By changing to 303, it is possible to further increase the adjustment range of the resistance value R between the electrodes obtained after selecting a set of electrodes.

  As described above, the combination of the resistance value selection method shown in FIGS. 5 and 6 and the resistance value adjustment method shown in FIGS. 3 and 4 requires a predetermined final resistance value R without trimming. It is possible to ensure with accuracy.

  FIG. 7 schematically shows a basic form when the thick film resistor of the present invention is realized in an actual resistor. The left side of the resistance wire (thick film resistor) 301 shown in FIG. 7 is a fine-tuning pattern in which wiring 302 is arranged from each bent portion 105 to each intermediate conductor 202, and one is placed on the right side. This is a coarse adjustment type pattern that is wired from the bent portion 105 to the intermediate conductor 202 by another kind of wiring 303. By providing both patterns on the left and right of one resistor, a device is devised to simultaneously increase both the width and accuracy of adjustment of the final resistance value R. In addition, in order to connect to an external element, a lead wire 102 is provided for each of the selected set of electrodes.

  The width and accuracy of the resistance value that can be adjusted differ depending on whether a resistance line or a conductive line is used as a connection line (wiring 302, another type wiring 303) from the bent portion 105 to each intermediate conductor 202. This will be described below for each of the fine adjustment pattern and the coarse adjustment pattern.

(1) Fine-tuning pattern FIG. 8 shows the fine-tuning pattern of this thick film resistor and the geometric size of the wiring, and enlarges the vicinity of one terminal conductor 201 and intermediate conductor 202. FIG.

The resistance wire 301 has a resistivity ρ, a cross-sectional area S, and a resistance value (the maximum resistance value of the thick film resistor, that is, the resistance value between the pair of terminal conductors 201) R ₀ . The bent portion 105 of the resistance wire 301 is counted in order from the terminal conductor 201, the distance from the terminal conductor 201 to the first bent portion is d ₀ , and the distance from the first bent portion to the second bent portion is l. ₀ , and the interval between the ninety-nine folds of the resistance wire 301 is d. Further, the intermediate conductor 202 connected from the nth bent portion 105 is referred to as an nth intermediate conductor, and is illustrated by a number in the drawing.

  First, the case where the wiring 302 is made of a conductor having a negligible resistance value (for example, the same material as the conductor serving as an electrode) will be described. At this time, as one set of electrodes, the resistance value Rn obtained when one is the termination conductor 201 and the nth intermediate conductor is selected for the other is given by equation (1).

  Next, the case where the wiring 302 is a resistance line having the same resistivity ρ as the resistance line 301 will be described. In this case, since there is resistance corresponding to the line length of the wiring 302 (linear distance to the intermediate conductor 202), a change in resistance value due to the change of the selected intermediate conductor 202 becomes small, and the resistance value Rn is expressed as in Formula (2). Therefore, the resistance value Rn can be adjusted with a fine value.

(2) Coarse / Fine Adjustment Pattern FIG. 9 is a schematic diagram showing the coarse adjustment pattern of the thick film resistor and the geometric size of the wiring. The vicinity of one terminal conductor 201 and intermediate conductor 202 is shown in FIG. FIG. The geometric size, the physical property value of the resistance wire 301, and the like are the same as those described above for the fine-tuning pattern. In FIG. 9, one of the ninety-nine bent portions 105 is gathered on one side (the upper side in FIG. 9) of the insulating substrate 101, so that another type of wiring 303 to the intermediate conductor 202 becomes one of the bent portions 105. It is arranged in parallel (every 99 cycles).

  First, the case where the connection wiring is a conductor and the electrical resistance is negligibly small will be described. At this time, as one set of electrodes, the resistance value Rn obtained when one is the termination conductor 201 and the nth intermediate conductor is selected for the other is given by Equation (3).

  Next, when the different type wiring 303 is a resistance line of the same type as the resistance line 301, the change in resistance value due to the change of the intermediate conductor 202 to be selected is reduced as in the fine adjustment type pattern. The resistance value Rn is expressed as in equation (4).

  As described above, when the fine adjustment type pattern and the coarse fine adjustment type pattern are configured as one resistor as shown in FIG. 7, the resistance value is determined using the conductive wire in the coarse adjustment type pattern as the wiring 302 or the different type wiring 303. It is reasonable to secure a large adjustment width and to improve the adjustment accuracy of the resistance value using a resistance wire in the fine adjustment type pattern.

  In addition, this thick film resistor is not restricted to this form. Either one of the adjustment patterns may be produced as necessary. Further, as the wiring 302 and the different type wiring 303, only a conductive wire or a resistance wire may be used, or a separate resistance paste material having a resistivity different from that of the resistance wire 301 may be used.

  FIG. 10 is a schematic diagram in the case where the lead wire electrode 203 for the lead wire 102 for connection to an external element is provided in the thick film resistor. The lead wire electrode 203 is connected to the terminal conductor 201 and the intermediate conductor 202 selected as a pair of electrodes by the first bonding wire 305 by means such as wire bonding. Although illustrated on the right side of the figure, parallel wiring is formed by bonding a plurality of intermediate conductors 202 (here, two as an example, but more than this) to the lead wire electrode 203 respectively. It becomes possible. As a result, it is possible to improve the adjustment accuracy of the final resistance value R.

  In FIG. 10, the parallel wiring is shown only for the right coarse adjustment pattern, but the parallel wiring is not limited to this example and can be implemented in the fine adjustment pattern (left side in FIG. 10). The number of parallel wirings (number of terminal conductors 201 and intermediate conductors 202 to be selected) is not limited to two, and may be more than two.

  Further, in the case of the thick film resistor of the form shown in FIG. 7, the position of the lead wire 102 differs for each resistor depending on the position of the selected intermediate conductor 202. The thick film resistor of the form shown in FIG. 10 is also effective when this inconsistency becomes a problem in design. That is, the shape of the entire resistor including the lead wire is unified. Furthermore, if the lead wire electrode 203 is made large, the lead wire 102 can be connected to an arbitrary position of the resistor as desired, and it is possible to give a structural space to the design of the device using the resistor. Become.

  FIG. 11 shows an example in which the relay electrode 204 is arranged between the terminal conductor 201 and the intermediate conductor 202 and the lead wire electrode 203 in the thick film resistor shown in FIG. The terminal conductor 201 or intermediate conductor 202 and the relay electrode 204 are connected by a first bonding line 305, and the relay electrode 204 and the lead wire electrode 203 are connected by a second bonding line 306.

  Compared with the thick film resistor of the second embodiment, the present thick film resistor can further finely adjust the final resistance value R by bonding due to the presence of the relay electrode 204. That is, when a wire made of a material having a significant resistance value is used as the second bonding wire 306, or when a wire rod thin enough to obtain a significant resistance value can be used, the number of the second bonding wires 306 Can be used for fine adjustment of the final resistance value R by controlling the value (illustrated on the left side of FIG. 11) or by changing the length of the second bonding line 306 (illustrated on the right side of FIG. 11). In addition, the effectiveness regarding the attachment position of the lead wire 102 is exactly the same as in the second embodiment.

The schematic diagram of the thick film resistor provided with the some electrode. The schematic diagram of the wiring pattern for enlarging the selection range of resistance value R, and a freedom degree. The schematic diagram explaining the method to raise the precision of resistance value R to select. The schematic diagram which shows the method of raising the selection accuracy of resistance value R with a relay electrode. The schematic diagram in case a resistance wire comprises a 99-fold pattern. The schematic diagram in case the length between the bending parts of a resistance wire is changing in steps. The schematic diagram of the basic form in the case of implement | achieving the thick film resistor of this invention in an actual resistor. The schematic diagram which shows the geometric size of a fine adjustment type | mold pattern and its wiring. The schematic diagram which shows the coarse adjustment type | mold pattern and the geometric size of the wiring. The schematic diagram which shows the Example at the time of providing a lead wire electrode. The schematic diagram which shows the Example at the time of providing a lead wire electrode and a relay electrode.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Insulating substrate, 102 ... Lead wire, 105 ... Bending part, 201 ... Termination conductor, 202 ... Intermediate conductor, 203 ... Lead wire electrode, 204 ... Relay electrode, 301 ... Resistance wire, 302 ... Wiring, 303 ... Different kind Wiring, 305 ... first bonding line, 306 ... second bonding line.

Claims (11)

On the insulating substrate, a resistance line made of a thick film resistor and a plurality of conductors that can be selected as electrodes of the resistance line are formed,
The plurality of conductors are connected to different portions on the resistance wire so that the resistance value of the resistance wire can be adjusted by selection of these conductors.   The plurality of conductors that can be selected as electrodes of the resistance line are a termination conductor connected to both ends of the resistance line, and a plurality of conductors connected to different portions between the both ends of the resistance line via wiring, respectively. The thick film resistor according to claim 1, comprising the intermediate conductor.   3. The thick film resistor according to claim 2, wherein each wiring that connects different portions of the resistance wire and the plurality of intermediate conductors that can be selected as electrodes is formed of a wire having a different resistance value.   4. The thick film resistor according to claim 2, wherein the resistance wire forms a 99-fold bent pattern, and each intermediate conductor is connected to each bent portion of the resistance wire via the wiring. vessel.   The thick film resistor according to claim 4, wherein a wire length between bent portions of the resistance wire forming the 99-fold is changed stepwise.   The thick film resistor according to claim 4 or 5, wherein a material of the wiring connected to the resistance wire forming the 99-fold is the same type as the resistance wire or the same type of the conductor that can be selected as an electrode. . The resistance wire forming the 99-fold has the longest length of the wire between the bent portions in the central region, and the length of the wire between the bent portions in the regions on both sides thereof is shifted to both ends of the insulating substrate. Gradually shortened as
The termination conductor and the intermediate conductor that can be selected as electrodes of the resistance wire are disposed along each side of the both ends of the insulating substrate. The thick film resistor described in the item.   The resistance wire forming the ninety-nine fold has a fine adjustment pattern in which a resistance value can be fine-adjusted by a conductor selected as an electrode and a coarse adjustment pattern in which coarse adjustment can be made. A thick film resistor according to claim 1.   The thick film resistor according to any one of claims 1 to 8, wherein a lead wire for electrical connection with the outside is connected to a pair of electrodes selected from the plurality of conductors.   A pair of lead wire electrodes for connecting lead wires is provided on the insulating substrate, and each lead wire electrode and one or more conductors selected from the plurality of conductors are connected by bonding wires. The thick film resistor according to any one of claims 1 to 9.   A pair of lead wire electrodes for connecting lead wires on the insulating substrate, and a relay electrode for connecting the lead wire electrodes and one or more conductors selected from the plurality of conductors. 11. The formed relay electrodes and the lead wire electrodes, and the relay electrodes and the conductors selected as the electrodes are connected to each other through bonding wires having various resistance forms. The thick film resistor according to any one of the above.

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