JP4109645B2 - Manufacturing method of chip resistor - Google Patents

Description

  The present invention provides a chip resistor having a structure in which a pair of electrodes is provided at both ends of a rectangular insulating substrate, a resistor such as a thick film is disposed between the electrodes, and the resistor is covered with a protective film, and a method for manufacturing the chip resistor About.

Conventionally, the chip resistor having the above structure is mounted on various electronic devices and is widely used in various industrial fields. Such a chip resistor is provided with a pair of front and back electrodes on the front and back surfaces of a rectangular insulating substrate such as alumina, and a resistor is disposed on the surface side of the insulating substrate so as to be connected to the front surface electrode. It is configured by covering with a protective film and forming electrodes including plating layers on the front, side, and back surfaces of both ends of the insulating substrate (see, for example, Patent Document 1).
Utility Model Registration No. 2545546

  The size of the chip resistor is varied from a relatively large size of, for example, about 3.2 mm × 1.6 mm to a small size of about 0.4 mm × 0.2 mm, and the size of the chip resistor is gradually increased. It tends to be miniaturized.

  FIG. 8 shows a configuration example of a conventional chip resistor. Surface electrodes 12 and 13 are disposed at both end portions on the surface side of the rectangular insulating substrate 11, and a resistor 16 connected to the surface electrodes 12 and 13 is disposed between the surface electrodes 12 and 13. Then, protective films 17 and 18 for covering and protecting the resistor 16 are disposed.

  In the above chip resistor, a large-sized insulating substrate is prepared, and electrodes, resistance films, and protective films are collectively formed by screen printing for each chip section, and then a large-sized insulating substrate is supported for a large number of chip sections. Individual chip resistors are manufactured by dividing or cutting the insulating substrate. For this reason, the thickness of the insulating substrate 11 tends to become thinner as the size of the chip resistor becomes smaller. The surface of the protective film 18 also tends to be rounded as the chip size becomes smaller. For this reason, the top part A which is the highest part of the chip resistor is formed in the vicinity of the central part of the protective films 17 and 18.

  When the chip resistor is mounted on a printed board or the like, the chip resistor is vacuum-sucked by a suction nozzle, and the chip resistor is mounted on a predetermined land on the printed board. In this mounting, if the vacuum nozzle is pressed, the pressing force concentrates on the top portion A of the rounded protective film 16 on the chip resistor surface side, and the chip resistor may be cracked.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a chip resistor excellent in mounting stability and a method for manufacturing the chip resistor when the chip resistor is mounted on a printed circuit board or the like. .

In order to solve the above problems, a chip resistor of the present invention is formed on an insulating substrate, a surface electrode made of a pair of thick film electrode materials formed on the surface side of the insulating substrate, and a back surface side of the insulating substrate. A back electrode made of a pair of thick film electrode materials , a resistor made of a thick film resistor material formed on the surface side of the insulating substrate and connected to the surface electrode, and covering and protecting the resistor In a chip resistor comprising a protective film, an auxiliary film is formed at both ends of the protective film, the auxiliary film is formed at a position away from the end face of the insulating substrate, and the auxiliary film is within the range of the back electrode. The auxiliary film is formed so as to be at the same height as or higher than the central portion of the protective film .

  According to the chip resistor of the present invention, two rows of linear apexes are formed of the auxiliary film at both ends of the protective film in plan view. Thereby, it can adsorb | suck stably to an adsorption | suction nozzle with the linear top part of 2 rows of this invention with respect to the conventional one point of roundness. And when mounting on the predetermined land of a printed circuit board, the pressing force of a suction nozzle can be directly applied to the back surface electrode located under the said auxiliary | assistant film | membrane. Thereby, the problem of occurrence of cracks in the chip resistor can be prevented.

Further, the method of manufacturing a chip resistor according to the present invention includes a step of forming a surface electrode and a back electrode on the front and back surfaces of a large insulating substrate using a thick film electrode material, and the surface of the insulating substrate on the surface side. A step of forming a resistor using a thick film resistor material in connection with an electrode; a step of covering the resistor with a protective film; and both ends of the protective film, separated from an end surface of the insulating substrate A step of forming an auxiliary film having a straight line shape in plan view, the height of which is equal to or higher than that of the central portion of the protective film, above the back electrode at a position, and dividing the large insulating substrate into strips A step of stacking a plurality of insulating substrates divided into strips so that the auxiliary film and the lower electrode are in contact with each other, sputtering is performed from the end surface side of the stacked insulating substrate, and the end surface of the insulating substrate In the surface electrode and the back surface A step of dividing causes short-circuiting the poles, a step of film by sputtering from the gap of the insulating substrate to form an end face electrode wraps around on the surface electrode, the insulating substrate is divided into strips into chips, the surface And a step of plating the surfaces of the electrode, the back electrode, and the end electrode.

  According to the present invention, a chip resistor having excellent mounting stability is provided in which two rows of top portions are formed by the auxiliary films provided at both ends of the protective film of the chip resistor.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the member or element which has the same effect | action or function, and the overlapping description is abbreviate | omitted.

  FIG. 1 shows a configuration example of the chip resistor according to the first embodiment of the present invention. This chip resistor includes front surface electrodes 12 and 13 and back surface electrodes 14 and 15 on the front and back surfaces of a rectangular insulating substrate 11 such as alumina. These electrodes are formed by patterning a thick film electrode material such as silver palladium by screen printing and baking at a high temperature. A thick film resistor 16 is disposed between the electrodes 12 and 13 on the surface side of the insulating substrate 11 so as to be connected to these electrodes. The resistor 16 is also formed by patterning and baking a thick film resistor material such as ruthenium oxide by screen printing.

  A glass coat 17 and a resin coat (overcoat) 18 constituting a protective film are formed on the surface of the resistor 16 so as to cover the resistor 16. The glass coat 17 is formed by patterning and baking a glass material by screen printing. The resin coat 18 is also formed by patterning a resin material by screen printing and heating and curing. The glass coat 17 and the resin coat 18 serve to cover and protect the resistor 16.

  Side electrodes 21 and 22 are formed by sputtering on the end surfaces of both ends of the insulating substrate 11 to connect the surface electrodes 12 and 13 and the back electrodes 14 and 15. And the plating electrode 23 which coat | covers each electrode surface is formed in the surface of the surface electrode 12, the side electrode 21, and the back surface electrode 14 of one edge part. Similarly, on the surface of the surface electrode 13, the side electrode 22, and the back electrode 15 at the other end, a plating electrode 24 that covers each electrode surface is formed.

  In the chip resistor of the present invention, auxiliary films 19 and 20 are formed on both ends of the protective films 17 and 18. The auxiliary films 19 and 20 are raised layers, and are formed, for example, by forming a pattern by screen printing of an epoxy resin material and heating and curing. By forming the film thick, the raised portions are formed in two rows in plan view so as to be substantially the same height as the central portions of the rounded protective films 17 and 18, preferably higher than this. By providing the auxiliary films 19 and 20 as the raised portions, the two highest rows of apexes A and A on the surface side of the chip resistor are formed at both ends of the protective films 17 and 18. The auxiliary films 19 and 20 are disposed above the back electrodes 14 and 15, respectively. Specifically, the surfaces of the plating electrodes 23 and 24 covering the back electrodes 14 and 15 form the highest peak on the back side of the chip resistor. That is, the auxiliary films 19 and 20 are formed so as to be positioned within the range of the back electrodes 14 and 15 constituting the top part on the back side of the chip resistor, respectively.

  FIGS. 2A and 2B show a state when the chip resistor is sucked by the suction nozzle when mounted. When mounting the chip resistor on a printed circuit board or the like, the chip resistor is vacuum-sucked using the vacuum suction nozzle 30 and moved to a predetermined mounting site on the printed circuit board. FIG. 2A shows a state where the chip resistor 10 of the present invention is attracted. As shown in the figure, the chip resistor 10 of the present invention includes two rows of linear top portions A and A, and therefore can be stably adsorbed to the adsorption nozzle 30 by vacuum suction. In contrast, FIG. 2B shows a state in which the conventional chip resistor 1 is attracted. Since the conventional chip resistor 1 has one point A on the rounded protective film, the state adsorbed by the adsorption nozzle 30 becomes unstable as shown in the figure.

  FIGS. 3A and 3B show a state where the chip resistor is mounted on a printed circuit board. 3A shows the mounting state of the chip resistor of the present invention, and FIG. 3B shows the mounting state of the conventional chip resistor for comparison. For mounting on the printed board, cream solder or the like is applied in advance to the lands 32 and 33 which are mounting portions of the printed board 31 by screen printing or the like, and the back electrodes 14 and 15 of the chip resistor 10 are applied to the lands 32 and 33. The suction nozzle 30 that sucks the surface side of the chip resistor is lowered so that is positioned, and the chip resistor 10 is pressed with a predetermined pressure.

  At the time of this pressing, two rows of raising auxiliary films 19 and 20 are arranged at both ends of the protective films 17 and 18, and two rows of apexes A and A on the chip resistor surface side are formed at both ends of the protective film. Therefore, the pressing force of the suction nozzle 30 is applied to the top portions A and A of the two rows. For this reason, since the site | part to which the pressing force of the suction nozzle 30 applies is shifted and distributed to the both ends of a chip resistor, the crack of a chip resistor can be suppressed. Further, in the present embodiment, the two rows of auxiliary films 19 and 20 are positioned above the back electrodes 14 and 15, respectively, so that the pressing force of the suction nozzle 30 is directly applied to the back electrodes 14 and 15. Therefore, since the load due to the pressing force of the suction nozzle 30 is directly applied to the back electrodes 14 and 15, the chip resistor can be prevented from cracking.

  On the other hand, in the case of the chip resistor 1 of the conventional example, the top portion A of the chip resistor exists at one point in the central portion of the protective films 17 and 18 as shown in FIG. The pressing force of the suction nozzle 30 is applied, and this load is concentrated at the substantially central portion of the insulating substrate 11 between the back electrodes 14 and 15. For this reason, there was a problem that cracks are likely to occur during mounting. As described above, in the chip resistor 10 of the present invention, since the two rows of linear apexes A and A are positioned above the back electrode, the load of the suction nozzle is dispersed and the back electrodes 14 and 15 are directly used. Is applied directly on top of. Thereby, the back side electrode portion of the chip resistor can be stably and reliably mounted on the land pattern.

  Next, with reference to FIG. 4, the manufacturing method of the chip resistor of this invention is demonstrated. First, a large-sized insulating substrate such as alumina is prepared. This large-sized insulating substrate is a multi-piece substrate, and only one chip section 11 that will later become a chip resistor is shown in FIG. 4B, a thick film electrode paste such as silver palladium is formed on the back surface of the insulating substrate 11 by screen printing and baked to form the back electrodes 14 and 15. Next, as shown in FIG. 4C, a thick film electrode paste such as silver palladium is patterned on the surface side of the insulating substrate 11 by screen printing or the like, and baked to form the surface electrodes 12 and 13. In addition, a surface electrode and a back surface electrode may form a surface electrode previously, and you may make it form a back surface electrode after that.

  Next, as shown in FIG. 4D, the thick film resistor 14 is disposed so as to be partially connected to the surface electrodes 12 and 13 on the surface side of the insulating substrate 11. The resistor 14 is formed by patterning a thick film resistor paste such as ruthenium oxide by screen printing and baking at a high temperature. Next, as shown in FIG. 4E, a glass coat 17 that covers the resistor 16 is formed. The glass coat 17 constitutes a lower protective film, and is formed by patterning and baking a glass material paste by screen printing. Next, as shown in FIG. 4F, a resin coat (overcoat) 18 that further covers the glass coat 17 is disposed. The resin coat 18 is formed by patterning a resin material paste such as epoxy, for example, by screen printing and heating and curing. The resin coat 18 constitutes an upper protective film.

  Next, as shown in FIG. 4G, auxiliary films 19 and 20 that are two rows of raised portions are formed on both ends of the overcoat 18. The auxiliary films 19 and 20 are formed by patterning by screen printing using a resin material paste such as epoxy as described above, followed by heat curing. Here, the auxiliary films 19 and 20 are formed so as to be located above the back electrodes 14 and 15. And the auxiliary | assistant films | membranes 19 and 20 are the raising parts, and are formed thickly so that the highest top part may be formed in the surface side of a chip resistor. A highly viscous paste material may be used to stabilize the shape of the auxiliary film.

  Next, the large insulating substrate is divided or cut into strips. As shown in FIG. 4 (h), the end electrodes 21 and 22 for short-circuiting the front electrodes 12 and 13 and the back electrodes 14 and 15 on the end surface of the insulating substrate divided into strips are made of a metal material such as NiCr. It is formed by sputtering. Then, the insulating substrate divided or cut into strips is divided or cut into individual chips. Next, as shown in FIG. 4 (i), the surfaces of the surface electrodes 12, 13, the back electrodes 14, 15, and the end electrodes 21, 22 are subjected to nickel plating, solder plating, and the like to form plated electrodes 23, 24. To do.

  Thus, the electrodes 22 and 23 are provided at both ends of the rectangular insulating substrate 11, the resistor 16 is disposed between the surface electrodes 12 and 13, and the resistor is covered with the protective films 17 and 18 made of glass coat and resin coat. Further, the chip resistor 10 which is protected and has auxiliary films 19 and 20 which are raised portions at both ends of the protective films 17 and 18 is completed.

  When forming the end face electrode by sputtering, in the chip resistor of the present invention, it is possible to accurately form the wraparound of the sputtering film to the front and back electrode sides. That is, as shown in FIG. 5 (a), in the sputtering step, the chip resistor of the present invention has a jig so that the auxiliary films 19 and 20 are in contact with the lower surface electrodes 14 and 15 of the adjacent chip resistors. Is loaded. For this reason, the sputtering film formed on the front surface electrode around the gap S between the adjacent chip resistors is indicated by the symbol G due to the contact portion with the adjacent back surface electrode on the substantially linear top. It is formed in a substantially linear shape. For this reason, the plating electrodes 23 and 24 deposited on the sputtering film are formed in a good shape without causing variations.

  In contrast, in the conventional chip resistor, the surface of the protective film is rounded as described above. For this reason, the contact part between the edge part of the lower surface electrodes 14 and 15 and the protective film 18 is limited to a part, and a gap is generated on both sides of the protective film. For this reason, the sputtering film that wraps around the surface electrodes 12 and 13 does not become linear as indicated by the symbol G. Further, the distribution of the sputtering film also varies due to variations in the thickness of the protective film. For this reason, when the plating electrode is formed, the plating electrode has a curved shape on both sides of the protective film of the chip resistor, and there is a problem that the shape of the plating electrode becomes unstable.

  FIG. 6 shows a chip resistor according to a second embodiment of the present invention. In this chip resistor, auxiliary films 27 and 28 that are raised portions are formed at both ends of the resin coat 18. Here, the protective film is composed of a lower glass coat 17 covering the entire surface of the resistor 16 and a resin coat 18 partially covering the central portion of the glass coat 17, and auxiliary films 27 and 28 are adjacent thereto. Is formed. Also in this embodiment, the auxiliary films 27 and 28 are arranged substantially linearly in plan view at both ends of the protective films 17 and 18. Thus, when mounting the chip resistor on a predetermined portion of the printed circuit board by vacuum suction to the suction nozzle during mounting, it is common to the above embodiment that an equal load can be applied to the back electrodes 14 and 15. .

  In this embodiment, since the auxiliary films 27 and 28 are mainly formed on the glass coat 17 and the surface electrodes 12 and 13 having high flatness, the height of the auxiliary films 27 and 28 can be formed with high accuracy. Further, the auxiliary films 27 and 28 can perform the same protective function as the resin coat 18 by using the same material as the protective coat 18.

  FIG. 7 shows a chip resistor according to a third embodiment of the present invention. In this chip resistor, auxiliary films 27 and 28 which are raised portions are formed on both ends of the glass coat 17 and further covered with the resin coat 18. In this embodiment, the auxiliary films 27 and 28 are arranged substantially linearly in plan view so as to be sandwiched between both ends of the protective films 17 and 18. Therefore, the top portions A and A are formed as the highest portion of the resin coat 18. Thus, when mounting the chip resistor on a predetermined portion of the printed circuit board by vacuum suction to the suction nozzle during mounting, it is common to the above embodiment that an equal load can be applied to the back electrodes 14 and 15. .

  In these embodiments, the top portions A and A are both formed of a resin material film. For this reason, the film of the resin material comes into contact with the suction nozzle during mounting. Therefore, the problem that the electrode plating part does not contact the surface of the suction nozzle and the plating part adheres to the surface of the suction nozzle is prevented. In the conventional chip resistor, it is conceivable that this portion is formed higher than the top portion A of the protective film 18 by forming the electrode plating thick. However, according to the chip resistor of the present invention, such adsorption is performed. It is possible to suppress the occurrence of the problem of adhesion to the nozzle.

  In addition, although one Embodiment of this invention was described so far, it cannot be overemphasized that this invention is not limited to said Embodiment, In the range of the technical idea, it may be implemented with a different form.

It is sectional drawing which shows the structural example of the chip resistor of the 1st Embodiment of this invention. The state where the chip resistor is sucked to the suction nozzle is shown, (a) shows the case of the chip resistor of the present invention, and (b) shows the case of the chip resistor of the conventional example. It is a figure which shows the state at the time of mounting of a chip resistor, (a) shows the case where the chip resistor of this invention is mounted, (b) shows the case where the conventional chip resistor is mounted. It is a figure which shows the manufacturing method of the chip resistor of this invention, the left column shows a top view, and the right column shows sectional drawing. It is a figure explaining the wraparound of the sputtering film | membrane in the sputtering process for formation of an end surface electrode, (a) shows the case of the chip resistor of this invention, (b) shows the case of the chip resistor of a prior art example. . It is sectional drawing which shows the structural example of the chip resistor of the 2nd Embodiment of this invention. It is sectional drawing which shows the structural example of the chip resistor of the 3rd Embodiment of this invention. It is sectional drawing which shows the structural example of the chip resistor of a prior art example.

Explanation of symbols

1,10 Chip resistor 11 Insulating substrate (chip section)
12, 13 Front electrode 14, 15 Back electrode 16 Resistor 17 Glass coat (protective film)
18 Resin coat (protective film)
19, 20, 27, 28 Auxiliary films 21, 22 Side electrodes 23, 24 Plating electrode 30 Suction nozzle 31 Printed circuit board 32, 33 Land A Top G Sputtering film (plating electrode) boundary S Sap

Claims (1)

Forming a front electrode and a back electrode on the front and back surfaces of a large-sized insulating substrate using a thick film electrode material,
Forming a resistor on the surface side of the insulating substrate using a thick film resistor material connected to the surface electrode;
Coating the resistor with a protective film;
Both ends of the protective film, above the back electrode at a position away from the end face of the insulating substrate, the height of the protective film is the same as or higher than the central part of the protective film . Forming an auxiliary film;
Dividing the large insulating substrate into strips;
Stacking a plurality of insulating substrates divided into strips so that the auxiliary film and the bottom electrode are in contact with each other;
Sputtering is performed from the end surface side of the stacked insulating substrate, and the front surface electrode and the back surface electrode are short-circuited at the end surface of the insulating substrate, and the end surface electrode is formed so that the film formed by sputtering wraps around the front surface electrode from the gap between the insulating substrates. Forming a step;
Dividing the insulating substrate divided into strips into chips, and
Plating the surfaces of the front electrode, the back electrode and the end electrode; and
A method of manufacturing a chip resistor, comprising:

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