JPH0618123B2 - Network resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention forms a plurality of resistance elements in a row on an insulating substrate and insulates the upper surface of each resistance element and an electrode terminal communicating with the resistance element. The present invention relates to the structure of a chip network resistor (hereinafter simply referred to as a network resistor) formed by glass coating on the upper surface of a substrate.

[Conventional technology]

For example, as shown in FIGS. 9 to 12, this type of network resistor is formed by applying a conductive paste such as silver or palladium on a mask on the left and right ends of the upper surface of an insulating substrate 1 usually made of ceramic or the like. After firing, a pair of electrode terminals 2a, 2
After forming b at appropriate intervals, similarly, a resistor paste is similarly applied to the pair of electrode terminals 2a and 2b by masking and coating and firing to form the resistance elements 3, respectively.

Therefore, the resistance elements 3 are formed on the upper surface of the insulating substrate 1 in a line at a predetermined interval.

After that, with or without applying a passivation film for preventing contamination of the resistance element 3 or stabilizing the resistance film,
While measuring the resistance value of the resistance element 3 by bringing a probe (probe) into contact with each of the pair of electrode terminals 2a and 2b, trimming with a laser or the like is performed on the resistance element 3 so that the resistance value becomes a predetermined resistance value. Is adjusted to.

After the trimming process is completed, as shown by the alternate long and short dash line in FIG. 9, a protective film 5 such as a glass coating is formed by applying a glass paste on the upper surface of the insulating substrate 1 so as to cover the resistive element 3 and then firing it. To form.

The reason why the protective film is applied at least after the trimming step and before the plating step is as follows.

That is, conventionally, as shown in FIG. 9, an L-shaped or P-shaped plan view that communicates with one side edge 3a of the resistance element 3 orthogonal to the electrode terminals 2a and 2b is provided at a midway portion in the longitudinal direction of each resistance element 3. It was usual to form the striped trimming portions 4 in the same direction in plan view.

In this case, the L-shaped trimming portion 4 in plan view has a widthwise lateral trimming line 4a communicating with the one side edge 3a of the resistance element 3 and a longitudinal direction from one end of the lateral trimming line 4a (one electrode terminal 2a). The vertical trimming line 4b in the direction toward the direction), and the starting end of the horizontal trimming line 4a, which is the starting end of the trimming portion 4, completely crosses the one side edge 3a of the resistance element 3, so that laser trimming is performed. The irradiation of the laser beam is formed so as to start on the insulating substrate 1 outside the one end 3a of the resistance element 3.

Therefore, the starting end of the lateral trimming line 4a of the trimming portion 4 in the resistor element 3 at the frontmost position of the row faces the outer peripheral edge of the upper surface of the insulating substrate 1 and is close to the outer peripheral edge.

Then, when laser trimming is performed, the resistor of the resistance element 3 is evaporated and vaporized with a predetermined narrow width by the thermal energy, and the upper surface of the insulating substrate 1 at the portion irradiated with the laser beam at this time is removed. Simultaneously with the heat energy, the insulating substrate 1 is scraped off along the lateral trimming line 4a to form the concave groove portion 7 as illustrated in FIGS. 11 and 12.

On the other hand, after the trimming step, the electrode terminals 2a, 2b
In order to improve the electric continuity performance of, the nickel plating layer 8 is formed on the surface by plating as shown in FIG.
Further, the solder layer 9 is formed on the surface of the nickel plating layer 8 by plating or other means.

The plating step for forming the nickel plating layer 8 is a so-called barrel plating method, in which a large number of network resistors are placed in a basket and immersed in a plating solution. The above-mentioned protective film 5 is applied in advance so as not to plate the exposed portions.

[Problems to be Solved by the Invention]

By the way, as shown in FIG. 11, the edge of the protective film 5 is
If the groove portion 7 is insufficient so as to intersect with the starting end portion, the following problem occurs.

That is, in the step of applying the glass paste that is the material of the protective film 5, the paste does not reach the bottom surface of the starting end portion of the concave groove portion 7 due to the viscosity of the glass paste, and the bottom surface of the concave groove portion 7 and the lower surface of the protective film 5 A gap may remain between them (see FIGS. 11 and 12).

Then, during the barrel plating process, when the plating liquid penetrates into the gap during the plating process and reaches the exposed portion (trimming portion 4) of the resistance element 3, the resistance element 3 is a kind of electric conductor. , Metal ions (nickel ions) in the plating solution are attracted to the resistance element 3, and the plating metal grows from the surface of the resistance element 3 due to chemical substitution and reduction action with the metal in the resistance element 3. , The trimming portion 4 is electrically connected with the plated metal.

Therefore, although the bending resistance film element 3 is partially cut off in the previous step and adjusted to a predetermined resistance value, the resistance value changes significantly, resulting in a so-called defective product.

Further, even if the trimming section 4 is not made conductive,
If the low-antibody chips removed during the trimming process remain at the bottom of the groove 7, the plated metal grows from the chip, and the plated metal passes through the groove 7 to form the edge of the protective film 5. It may project further outward, and in this case, in the solder plating step when mounting the later network resistor on the circuit board (printed wiring board), the solder plating is connected to the projecting plated metal, Various inconveniences may occur, which may lead to poor electrical characteristics and noise.

In order to avoid this inconvenience, the edge of the protective film 5 must also cover the starting end portion of the concave groove portion 7 which is the starting end of the lateral trimming line 4a, in other words, the outer edge of the insulating substrate 1 must be exactly coated. I won't.

However, since the glass paste applied as the protective film 5 is a fluid, it is difficult to apply the glass paste exactly so that the edge of the glass paste is exactly on the outer edge of the insulating substrate 1 as described above. If it is too large, the back surface of the insulating substrate 1 will hang down, and if it is insufficient, the above-mentioned inconvenience cannot be solved.

To avoid such inconvenience, a so-called passivation film 10 is applied before the trimming process of the resistance element 3 (see FIG. 14), and a manufacturing process is adopted in which the resistance element 3 and the passivation film 10 are simultaneously cut off during trimming. But the same happened.

When the edge of the passivation film 10 is located outside the one side edge 3a of the resistance element 3, the trimming portion 4 is formed.
The starting end of the lateral trimming line 4a must be as close as possible to the outer edge of the insulating substrate 1 so as to cut off the edge of the passivation film 10 (otherwise, chips of the resistance element are likely to collect in the groove of the trimming portion. It was extremely difficult to form the protective film 5 again thereon before the plating process.

Further, in order to avoid the above-mentioned inconvenience, for example, as shown in FIG. 15 and FIG. 16, two resistance elements 3 and 3 adjacent to each other among the plurality of resistance elements 3 arranged in a row at appropriate intervals. When trimming in a U-shape in a plan view so that the starting ends of the lateral trimming lines 4a, 4a of the trimming portions 4, 4 communicate with each other,
Since the starting ends of the lateral trimming lines 4a, 4a are located not on the outer peripheral edge of the insulating substrate 1 but on the inner peripheral side (position closer to the central portion), protection is performed so as to cover the resistance elements 3, 3 before the plating process described above. The film 5 can entirely cover above the starting ends of the both lateral trimming lines 4a, 4a.

Therefore, there is no inconvenience such as the growth of plated metal during the above-mentioned plating process, but the following inconvenience occurs instead.

That is, the concave groove portions 7, 7 formed along both lateral trimming lines 4a, 4a of the two trimming portions 4, 4 communicate with each other. When the glass paste for the protective film 5 is applied over the upper surface of the insulating substrate 1 and the upper surfaces of the resistance elements 3 and 3, the viscosity of the glass paste does not reach the bottom surface of the concave groove portion 7 and a gap is formed. Sometimes.

Further, even if this gap does not occur, impurities such as chips of the resistor cut off during the trimming process remain as described above at the gap or at the boundary surface between the bottom surface of the concave groove portion 7 and the protective film 5, and the concave groove portion is formed. Due to the communication of 7 and the short distance between the resistance elements 3 and 3, a leak may occur between the adjacent resistance elements 3 and 3.

Therefore, it is impossible to perform the trimming in which the starting ends of the trimming portions communicate with each other outside one side portion of the two resistance elements adjacent to each other.

The present invention aims to solve these problems.

[Means for Solving the Problems]

In order to achieve this object, the present invention provides a pair of electrode terminals formed on the insulating substrate such that a plurality of resistance elements are arranged in a row on the upper surface of the insulating substrate at appropriate intervals, and both ends of each resistance element are formed on the insulating substrate. In the network resistor formed by connecting to, the starting end of the trimming line in the trimming portion formed in the middle of each resistance element is provided so as to start from one side edge of the resistance element extending in the direction of the pair of electrode terminals, and ,
Of the resistance elements arranged in a row, the starting ends of the trimming lines of the trimming portions formed on the resistance elements at the frontmost end position and the rearmost end position of the row are opposite to those facing the outer peripheral edge of the insulating substrate. The trimming line of the trimming portion of the resistance element on the opposite side adjacent to the resistance element at the foremost end position and the rearmost end position of the row and the trimming line of the trimming portion of the other resistance element while being positioned near the circumference It is provided at a position that is staggered with respect to the start end of.

〔Example〕

Next, an embodiment of the present invention will be described. In FIG. 1, reference numeral 11 is an insulating substrate such as ceramic or glass similar to that in a conventional network resistor, and reference numerals 12a and 12b are longitudinal directions of the insulating substrate 11. A pair of electrode terminals formed by printing and firing a conductor paste on both left and right sides along the
a and 12b are provided.

Reference numeral 13 is a pair of the electrode terminals 12a and 12b.
A resistance element formed by printing and firing a paste for resistance on the upper surface of the insulating substrate 11 so that the ends overlap with each other is shown.

Reference numeral 14 is an L-shaped trimming portion in plan view formed by laser trimming in the middle of each of the resistance elements 13 in the longitudinal direction. The trimming portion 14 includes the pair of electrode terminals 12.
A lateral trimming line 14a extending from the upper surface of the insulating substrate 1 in the vicinity of one side edge 13a of the resistance element 13 extending in the a and 12b directions in a direction intersecting the one side edge 13a at a substantially right angle, and the end of the horizontal trimming line 14a. And a vertical trimming line 14b which communicates with the first electrode terminal 12a and extends in the direction of the one electrode terminal 12a.

As shown in FIG. 2, when the trimming portion 14 is formed by laser trimming or the like, the upper surface of the insulating substrate 11 is shaved by the heat energy or the like, and the lateral trimming line 14a is formed.
The concave groove portion 16 is formed along this.

When two resistance elements 13 and 13 are arranged in a line (two-line network resistor), one resistance element 13 is at the frontmost position of the row and the other resistance element 13 Is the last position. Both resistance elements 13 and 1
Horizontal trimming line 1 of trimming portions 14 and 14 in FIG.
The starting ends of 4a and 14a are located closer to the inner circumference (the position closer to the central portion of the upper surface of the insulating substrate 11) opposite to the position facing the outer peripheral edge of the insulating substrate 11, and the resistance element 13 located at the frontmost position of the row. The starting end of the lateral trimming line 14a of the trimming portion 14 in the line is eclipsed by a distance (H1) from the starting end of the lateral trimming line 14a of the trimming portion 14 in the resistance element 13 on the opposite side (the end position) adjacent thereto. It is provided at the position.

In the trimming work for accurately adjusting the resistance value of the resistance element 13, first, a probe (probe) is brought into contact with the pair of electrode terminals 12a and 12b connected to the resistance element 13 at the foremost end position and the resistance between them is set. While detecting the resistance value of the element, the trimming portion 14 is formed, and when the resistance value reaches a predetermined value, the trimming work is stopped.

Then, while the resistance value is being measured in the same manner as described above, the trimming portion 14 is similarly formed at the location of the adjacent resistance element 13.

With this configuration, the starting end of the horizontal trimming line 14a of the trimming portion 14 in each resistance element 13 is the insulating substrate 1.
Since it is located at the substantially central portion of the upper surface of the upper surface of FIG. 1, after the trimming process and before the plating process, a protective film 15 (shown by a dashed line in FIG. Trimming lines 14a, 14
It is possible to completely cover the starting end of a and, in turn, the upper surface of the groove 16 formed in the upper surface of the insulating substrate.

As a result, in the plating process, it is possible to completely eliminate the inconvenience such as the plating metal growing from the starting ends of the both lateral trimming lines 14a, 14a and the recessed groove portion 16.

Since the starting ends of the both lateral trimming lines 14a, 14a are offset by a distance (H1) in a plan view, the concave portions 16 (formed on the upper surface of the insulating substrate 11 along the lateral trimming line 14a during the trimming process). (Representatively shown in FIG. 1) does not communicate with each other, and even if chips of the resistance element remain in each of the concave groove portions 16, the protective film 15 adhered to the upper surface of the planar insulating substrate 11 It is possible to insulatively cut off both of the starting ends.

FIG. 3 shows an embodiment in which three resistance elements 13 are arranged in a row (triple network resistor), and the trimming portion 14 of the resistance element 13 at the foremost end position (left end position in FIG. 3) is shown. The starting end of the lateral trimming line 14a should be formed in the rearward direction of the column, and the starting end of the lateral trimming line 14a of the trimming section 14 in the resistance element 13 at the rearmost position (the rightmost position in FIG. 3) should be formed in the frontward direction of the column. Thus, the starting ends of the horizontal trimming lines 14a of the trimming portions 14 of both the resistance elements 13 can be located at the inner peripheral portion of the upper surface of the insulating substrate 11, and the two resistance elements 13,
The starting end of the lateral trimming line 14a of the trimming portion 14 in the resistance element 13 at the intermediate position located between the two faces the lateral trimming line 14a of the trimming portion 14 in the resistance element 13 at the end position, and the distance (in plan view) H
It is formed so that they are displaced by 1) and disagree with each other.

FIGS. 4 and 5 each show an embodiment in which four resistance elements 13 are arranged in a line (a four-series network resistor), and in each of these embodiments as well, the frontmost position (left end of each drawing) is shown. Position) of the trimming portion 14 of the resistance element 13 at the starting position of the trimming portion 14 in the rear end position (right end position of each figure) of the trimming portion 14 of the trimming portion 14 of the starting end of the row. By forming each of them so as to face forward, the starting end of the lateral trimming line 14a of the trimming portion 14 in both resistance elements 13 can be positioned on the inner peripheral portion of the upper surface of the insulating substrate 11.

In the embodiment of FIG. 4, the starting ends of the lateral trimming lines 14a and 14a of the trimmings 14 and 14 in the second and third resistance elements 13 and 13 from the left end are located on the same left side one edge 13a side. . The starting end of the lateral trimming line 14a of the trimming 14 in the second resistance element 13 from the left end in the embodiment of FIG. 5 is directed toward the resistance element 13 side at the front end position, and the trimming 14 in the third resistance element 13 is performed.
The starting end of the horizontal trimming line 14a is the resistance element 1 at the rear end position.
It is formed so as to face the 3 side.

The embodiment shown in FIGS. 6, 7, and 8 includes five resistance elements 13.
In a row (5-series network resistor), the starting end of the horizontal trimming line 14a of each trimming section 14 as shown in the figure is the most resistive element in the row among the resistance elements arranged in a row. The starting end of the trimming line of the trimming part formed on the resistance element at the front end position and the rear end position is
While being positioned on the inner peripheral side opposite to the location facing the outer peripheral edge of the insulating substrate, the leading end of the trimming line of the trimming portion in the resistor element at the foremost end position and the trailing end position in the row and other resistor elements, and It is provided at a position staggered with respect to the starting end of the trimming line of the trimming portion in the resistance element on the opposite side adjacent to each other, and various arrangement patterns are conceivable as shown in the figure.

The location of the protective film 15 is omitted in FIGS. 4 to 8. In addition, the resistance element 13 is formed on the upper surface of the insulating substrate 11 by 2
It is needless to say that the electrodes may be arranged in three rows, and in that case, a part of the electrode terminals are formed near the inner circumference of the upper surface of the insulating substrate 11.

[Operation and effect of invention]

As described above, at least of the resistance elements arranged in a row at appropriate intervals, the starting ends of the trimming lines of the trimming portions formed on the resistance elements at the frontmost end position and the rearmost end position are located near the inner circumference on the upper surface of the insulating substrate. Therefore, after the trimming step and before the plating step, the upper surface of the starting end of the lateral trimming line can be sufficiently and completely covered with the protective film formed by the glass coating so as to cover all the resistance elements.

As a result, in the plating process, it is possible to completely eliminate the inconvenience such as the plating metal growing from the starting end of the lateral trimming line and further from the groove formed in the upper surface of the insulating substrate.

Then, the starting ends of the trimming lines of the trimming portions of the resistance elements at the frontmost position and the rearmost position of the row and the other resistance elements are compared with the starting ends of the trimming lines of the trimming portions of the resistance elements on the opposite side adjacent to the resistance element. Since it is provided in a staggered position in a plan view, the recessed grooves formed on the upper surface of the insulating substrate along the horizontal trimming line do not communicate with each other during the trimming process, and even if each of the recessed grooves has a resistance element Even if chips remain, the both ends can be insulated insulatively by the protective film that is in close contact with the upper surface of the planar insulating substrate.

As described above, according to the present invention, the adjustment accuracy of the resistance value is remarkably improved, and the stability of the electrical characteristics of the network resistor is remarkably improved.

INDUSTRIAL APPLICABILITY The present invention is effective when the outer peripheral edge of the protective film cannot be precisely positioned on the outer peripheral edge of the insulating substrate, for example, in the case of a minute shape in which the length and width dimensions of the resistance element in the resistance network are short, and The formation of the protective film can also be omitted.

[Brief description of drawings]

1 to 8 show an embodiment of the present invention, FIG. 1 is a perspective view, FIG. 2 is a plan view of a double network resistor, and FIG. 3 is a plan view of a triple network resistor. , FIG. 4 and FIG. 5 are plan views of a 4-series network resistor, FIG. 6 and FIG. 7 and FIG. 8 are plan views of a 5-series network resistor, and FIG. 9 to FIG. Show a conventional example,
FIG. 9 is a plan view of a conventional dual network resistor, the first
0 is an enlarged sectional view taken along line XX of FIG. 9, FIG. 11 is an enlarged sectional view taken along line XI-XI of FIG. 9, and FIG. 12 is taken along line X- of FIG.
II-XII sectional view, FIG. 13 is a perspective view, FIG. 14 is a perspective view of a conventional example, FIG. 15 is a plan view showing still another example of the conventional example, and FIG. 16 is XVI- of FIG. FIG. 6 is an enlarged cross-sectional view taken along XVI. 1, 11 ... Insulating substrate, 2a, 2b, 12a, 12b ...
... Electrode terminals, 3, 13 ... Resistance elements, 4, 14 ... Trimming part, 4a, 14a ... Horizontal trimming line, 5, 15
...... Protective film, 7, 16 ...... concave groove part, 8 ...... nickel plating layer, 9 ...... solder layer, 10 ...... passivation film.

Claims (1)

[Claims] 1. A plurality of resistance elements are arranged in rows on an upper surface of an insulating substrate at appropriate intervals, and both ends of each resistance element are connected to a pair of electrode terminals formed on the insulating substrate. In the network resistor configured as described above, the starting end of the trimming line in the trimming portion formed in the middle of each resistance element is provided so as to start from one side edge of the resistance element extending in the direction of the pair of electrode terminals, and the row Position the starting ends of the trimming lines of the trimming portions formed on the resistance elements at the frontmost position and the rearmost position of the row of the resistance elements arranged in a line, on the inner surface side opposite to the location facing the outer peripheral edge of the insulating substrate. On the other hand, the starting ends of the trimming lines of the trimming portions of the resistance elements at the foremost end position and the rearmost end position in the row and the trimming portions of the other resistance elements are connected to the resistance of the other side adjacent thereto. Resistor networks, characterized in that provided on the discrepancy shaped position relative to the starting end of the trimming line of the trimming portion in the element.