JP2017220589A - Manufacturing method of chip resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a chip resistor, capable of easily and surely forming an end surface electrode.SOLUTION: After a pair of first and second front electrodes 3 and 4 or a resistor 5 or the like is formed to a large scale substrate 11 to which a first dividing groove 12 and a second dividing groove 13 extended in a lattice state are formed, a double strip-like substrate 11A having two strip-like parts is obtained by alternately primary dividing the large scale substrate 11 along the first division groove 12. Sequentially, after an end surface electrode 8 is formed on both division surfaces of the double strip-like substrate 11A, the double strip-like substrate 11A is secondary divided into two strip-like substrates 11B along the first division groove 12 of a center, and the two strip-like substrates 11B are thirdly divided into a chip unit 11C along the second division groove 13.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for manufacturing a chip resistor in which a plurality of sets of electrodes, resistors, etc. are formed on a large substrate, and then the large substrate is divided into a lattice and divided into individual pieces. The present invention relates to a method of manufacturing a chip resistor in which any of electrodes, resistors, end electrodes, etc., which are constituent elements of the device, is non-axisymmetric with respect to a center line that bisects the surface of the insulating substrate in the left-right direction.

  Conventionally, as described in Patent Document 1, the area of two surface electrodes connected to a resistor is made different, and the surface electrode with the larger area is used as the wire bonding electrode, and the area with the smaller area is used. There has been proposed a chip resistor in which an end face electrode that conducts to a surface electrode is used as a terminal electrode for soldering.

  Usually, when manufacturing such a chip resistor, a large substrate having a primary dividing groove and a secondary dividing groove extending in a lattice shape is prepared, and a large number of electrodes and resistors are formed on the large substrate. After forming the body and the protective film in a lump, the large-sized substrate is primarily divided (breaked) along the primary dividing groove to obtain a strip-shaped substrate, and then only on one divided surface of the strip-shaped substrate. The end face electrodes are formed by sputtering or coating, and then the strip-shaped substrate is secondarily divided along the second divided grooves, so that a large number of individual chips are obtained. Yes.

Japanese Patent Laid-Open No. 9-162002

  However, when the end face electrode is formed only on one end face of the insulating substrate, such as the chip resistor described in Patent Document 1, when the end face electrode is formed on one divided face of the strip-shaped substrate. In addition, if the end face electrode is formed on the other divided surface by mistake, it becomes a defective product. That is, since the directionality is generated in the strip-shaped substrate in the step of forming the end face electrodes, there is a possibility that a manufacturing error may occur unless the directionality is strictly managed.

  In addition, when the end face electrodes are formed by sputtering on the dividing surface of the strip-shaped substrate, it is common to form the end face electrodes at once for a plurality of strip-shaped substrates stacked in the vertical direction. In the case of a chip resistor in which the layer is formed at a position deviated from the center of the insulating substrate, the cross-sectional shape along the width direction of the strip substrate becomes asymmetrical, so multiple strip substrates are placed in a horizontal position. There is also a problem that it becomes impossible to form the end face electrodes and it becomes extremely difficult to form the end face electrodes.

  The present invention has been made in view of such a state of the art, and an object of the present invention is to provide a method of manufacturing a chip resistor capable of easily and reliably forming an end face electrode.

  In order to achieve the above object, a method for manufacturing a chip resistor according to the present invention prepares a large substrate having a large number of first division lines and second division lines extending in a lattice shape, and the surface of the large substrate. Forming a pair of electrodes spaced apart from each other at a predetermined interval in each chip formation region partitioned by the first division line and the second division line, and a resistor straddling the electrodes. A double substrate in which two strip-shaped portions are connected via the first division lines by primary division of the large substrate on which the electrodes and the resistors are formed along every other first division line. A step of obtaining a strip-shaped substrate; a step of forming end face electrodes that are electrically connected to the electrodes on both opposing surfaces of the double strip-shaped substrate; and the double strip-shaped substrate having the end face electrodes formed thereon Split line A step of obtaining a strip-shaped substrate by dividing the strip-shaped substrate along the second dividing line, and a step of dividing the strip-shaped substrate into a plurality of single chips. It is said.

  After forming the end face electrodes on both split surfaces of the double strip substrate where the two strip portions are connected via the first split line in this way, the double strip substrate is formed into two strip shapes along the first split line. When the substrate is divided into two, the direction of the double strip substrate is lost when the end surface electrode is formed, so that a manufacturing error that the end surface electrode is formed on the wrong end surface of the strip substrate can be eliminated. In addition, even when the electrodes and resistors are formed at a biased position to form an asymmetric strip-shaped substrate, symmetry is maintained in the double strip-shaped substrate before secondary division into the strip-shaped substrate. Double strip substrates can be stacked in a horizontal orientation, and end electrodes can be collectively formed by sputtering on the divided surfaces of the plurality of double strip substrates.

  In the above manufacturing method, the primary division and the secondary division along the first division line may be performed by dicing or laser scribing, but the first division line is a division groove formed on a large substrate, and 2 When the groove depth of the divided groove to be primarily divided is set larger than the groove depth of the divided groove to be divided next, a double strip substrate in which two strip portions are connected from a large substrate can be easily obtained. Can be obtained.

  Alternatively, the first dividing line is a dividing groove formed on the large substrate, the dividing groove to be primarily divided is formed on the surface of the large substrate, and the dividing groove to be divided second is on the back surface of the large substrate. When formed, a double strip substrate in which two strip portions are connected to a large substrate can be easily obtained.

  In the above manufacturing method, one of the pair of electrodes formed in the chip formation region of the large-sized substrate is formed so as to straddle the first division line that is primarily divided, and the other electrode is 2 If it is formed at a position away from the first division line to be divided next, when manufacturing a chip resistor that can be mounted by using both soldering and wire bonding, the end face electrode is reliably conducted to the soldering electrode. The short circuit of the wire bonding electrode can be eliminated.

  In this case, the two sets of electrodes formed on the double strip-shaped substrate have a line-symmetric shape with respect to the first dividing line, and among these electrodes, the electrode closer to the first dividing line is the farther one. If formed larger than the electrode, the wire can be easily connected to the wire bonding electrode having a large area.

  In the manufacturing method of the chip resistor according to the present invention, after the end face electrodes are formed on both split surfaces of the double strip substrate in which the two strip portions are connected via the first split line, the double strip substrate is first split. The secondary electrode is divided into two strip-shaped substrates along the line, and then the strip-shaped substrate is divided into three pieces along the second dividing line so as to be separated into a large number of single chips. Can be formed easily and reliably.

It is sectional drawing of the chip resistor which concerns on the example embodiment of this invention. It is explanatory drawing which shows the state which mounted this chip resistor in the circuit board. It is explanatory drawing which shows the manufacturing process of this chip resistor. It is explanatory drawing which shows the manufacturing process of this chip resistor. It is explanatory drawing which shows the manufacturing process of this chip resistor. It is explanatory drawing which shows the manufacturing process of this chip resistor. It is sectional drawing which shows the modification of the large format board | substrate used by the manufacturing process of this chip resistor. It is sectional drawing which shows the modification of the large format board | substrate used by the manufacturing process of this chip resistor.

  DESCRIPTION OF EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a chip resistor 1 according to an embodiment of the present invention has a rectangular parallelepiped insulating substrate 2 and a predetermined surface on the surface of the insulating substrate 2. A first surface electrode 3 and a second surface electrode 4 formed at intervals, a resistor 5 formed so as to bridge the first and second table electrodes 3 and 4, and a resistor 5 A protective film 6 to be covered, a back electrode 7 formed on the back surface of the insulating substrate 2, an end face electrode 8 conducting the back electrode 7 and the first front electrode 3, a first front electrode 3, the back electrode 7 and the end face electrode 8. The first external electrode 9 that covers the exposed portion of the second outer electrode 10 and the second external electrode 10 that covers the exposed portion of the second front electrode 4.

  The insulating substrate 2 is an alumina substrate made of ceramics, and the insulating substrate 2 is divided into a plurality of large substrates, which will be described later, by dividing (breaking) along a first dividing groove and a second dividing groove extending vertically and horizontally in a lattice shape. It is a thing.

  The first table electrode 3 and the second table electrode 4 are obtained by screen-printing Ag-Pd paste on the surface of the insulating substrate 2, drying and firing the first table electrode 3, and the second table electrode 4 with respect to the first table electrode 3. The size is considerably larger. Further, the first surface electrode 3 is formed in the vicinity of the left end surface of the insulating substrate 2 in the drawing, but the second surface electrode 4 is formed in an inward position at a predetermined distance from the right end surface of the insulating substrate 2 in the drawing. Has been.

  The resistor 5 is obtained by screen-printing a resistance paste such as ruthenium oxide on the surface of the insulating substrate 2 and then drying and baking. Both ends of the resistor 5 in the longitudinal direction overlap the first surface electrode 3 and the second surface electrode 4 and are not shown in the figure, but the resistor 5 is formed with a trimming groove for adjusting the resistance value. Has been.

  The protective film 6 has a two-layer structure of an undercoat layer and an overcoat layer, of which the undercoat layer is a screen paste of glass paste dried and fired, and the overcoat layer is a screen print of an epoxy resin paste. And heat-cured.

  The back electrode 7 is obtained by screen-printing Ag—Pd paste on the entire back surface of the insulating substrate 2, drying and firing.

  The end surface electrode 8 is formed by sputtering Ni—Cr or the like on the end surface of the insulating substrate 2, and this end surface electrode 8 is formed on the left end surface of the insulating substrate 2 in the figure to conduct the first front electrode 3 and the back electrode 7. ing.

  The first and second external electrodes 9 and 10 have a two-layer structure of a barrier layer and an external connection layer, of which the barrier layer is a Ni plating layer formed by electrolytic plating, and the external connection layer is formed by electrolytic plating. It is an Au plating layer. Here, the second external electrode 10 covers the surface and end surface of the second front electrode 4 exposed from the protective film 6, and the second external electrode 10 is also spaced a predetermined distance from the right end surface of the insulating substrate 2 in the drawing. It is formed in the inward position.

  The chip resistor 1 configured as described above is mounted on the circuit board 20 by using both soldering and wire bonding as shown in FIG. That is, the circuit board 20 is provided with a wiring pattern 21 and a wiring pattern (not shown) separated from each other, and the chip resistor 1 is mounted on one wiring pattern 21 and the first surface electrode 3 is mounted. The first external electrode 9 covering the back electrode 7 and the end face electrode 8 is fixed by the solder 22, and the second external electrode 10 covering the second front electrode 4 is connected to the other wiring pattern via the wire 23. ing. The wire 23 is made of gold, aluminum, or the like, and is fixed to the second external electrode 10 and the wiring pattern using ultrasonic welding.

  Next, a manufacturing method of the chip resistor 1 configured as described above will be described with reference to FIGS. 3A to 3D are plan views of a large-sized substrate, FIGS. 4A to 4D are cross-sectional views taken along line X1-X1 in FIGS. 3A to 3D, and FIG. FIGS. 6A to 6D are plan views of a double strip substrate, a strip substrate, and a single chip, and FIGS. 6A to 6D are cross-sectional views taken along lines X2-X2 in FIGS. Respectively.

  First, as shown in FIGS. 3A and 4A, a large-sized substrate 11 from which a large number of insulating substrates 2 are taken is prepared. A first divided groove 12 and a second divided groove 13 having a V-shaped cross section are provided in a lattice shape on the surface of the large-sized substrate 11, and each of the squares divided by the divided grooves 12 and 13 is provided. This is a chip formation region for one piece. FIG. 3 representatively shows a plurality of chip formation regions. Actually, however, each process described below is performed collectively on the large substrate 11 corresponding to a large number of chip formation regions. Is called.

  That is, Ag-Pd paste is screen-printed on the front and back surfaces of the large substrate 11 and dried and fired, whereby the first substrate is formed on the back surface of the large substrate 11 as shown in FIGS. 3B and 4B. A plurality of strip-like back electrodes 7 are formed so as to cross the dividing grooves 12, and a first surface electrode 3 and a second surface electrode 4 that form a pair in each chip formation region on the surface of the large-sized substrate 11 are formed (electrode formation). Process).

  Here, the first front electrode 3 is formed so as to straddle the arbitrary first divided groove 12, and the second front electrode 4 is formed at a separation position across the adjacent first divided groove 12. That is, when each chip formation region shown in FIG. 3B is viewed in order from the left side to the right side, the first table electrode 3, the second table electrode 4, the second table electrode 4, the first table electrode 3, The first table electrode 3, the second table electrode 4, the second table electrode 4,..., The first table electrode 3 and the second table electrode 4 that make a pair are alternately reversed in the continuous chip formation region. It is formed in the form. Therefore, in two chip formation regions that are continuous across an arbitrary first division groove 12, the pair of the first table electrode 3 and the second table electrode 4 has a line-symmetric shape with respect to a straight line along the first division groove 12. It has become.

  Next, a resistor paste such as ruthenium oxide is screen-printed on the surface of the large-sized substrate 11, and then dried and baked to form a pair as shown in FIGS. 3 (c) and 4 (c). A plurality of resistors 5 connected to the first table electrode 3 and the second table electrode 4 are formed (resistor forming step).

  Next, a glass paste is screen-printed on the surface of the large substrate 11, dried and fired to form an undercoat layer covering the resistor 5, and then a trimming groove (not shown) is formed on the undercoat layer. The resistance value is adjusted by forming. Thereafter, an epoxy resin paste is screen-printed so as to cover the undercoat layer and heat-cured, so that the undercoat layer and overcoat layer 2 are formed as shown in FIGS. 3 (d) and 4 (d). A protective film 6 having a layer structure is formed (protective film forming step).

  The process up to this point is a batch process for the large-sized substrate 11. Next, the large-sized substrate 11 is primarily divided along every other first dividing groove 12 to obtain FIGS. As shown in a), a plurality of double strip substrates 11A are obtained from the large substrate 11 (primary division step). At this time, the first dividing groove 12 extending longitudinally through the first surface electrode 3 is primarily divided, and the first dividing groove 12 passing between the pair of second surface electrodes 4 is not broken. Is in a state where the two strip-shaped portions are connected via the first dividing groove 12 remaining without being broken. A pair of front electrodes 3 and 4, a resistor 5 and a protective film 6 are formed on each of these two strip-shaped portions. As described above, two continuous chips are formed with the first dividing groove 12 interposed therebetween. In the region, the surface electrodes 3, 4 and the resistor 5 are symmetric with respect to the straight line along the first dividing groove 12, so that the two strip-shaped portions of the double strip substrate 11A have a symmetric shape. The surface electrodes 3 and 4 and the resistor 5 are formed.

  Next, both left and right ends of the double strip substrate 11A are sputtered by sputtering Ni—Cr or the like on both opposing surfaces of the double strip substrate 11A as shown in FIGS. 5B and 6B. The end face electrodes 8 are formed on the surface, and the end face electrodes 8 conduct the corresponding first front electrode 3 and back electrode 7 on the front and back surfaces of the double strip substrate 11A (end face electrode forming step). In such an end face electrode forming step, the end face electrodes 8 are formed by sputtering on a plurality of double strip-shaped substrates 11A stacked in the vertical direction. At that time, the double strip-shaped substrate 11A has left-right symmetry. Since it is maintained, each double strip substrate 11A can be aligned in a horizontal posture without tilting, and the end face electrodes 8 can be collectively formed on the split surface of the double strip substrate 11A by sputtering.

  Thereafter, the double strip-shaped substrate 11A is secondarily divided along the central first dividing groove 12, so that one double strip-shaped substrate 11A is formed as shown in FIGS. 5 (c) and 6 (c). Two strip-shaped substrates 11B are obtained (secondary division step). This strip-shaped substrate 11B has an end surface electrode 8 formed on one end surface in the end surface electrode forming step, but the end surface electrode is formed on the other end surface of the strip-shaped substrate 11B broken in the secondary division step. In addition, a predetermined interval is secured between the end surface (second divided surface) and the second surface electrode 4.

  Next, the strip-shaped substrate 11B is tertiary-divided along the second dividing groove 13, so that the strip-shaped substrate 11B is equivalent to a chip resistor as shown in FIGS. 5 (d) and 6 (d). A large number of single chips 11C having a size are taken (tertiary division step).

  Next, by applying electrolytic plating such as Ni to the singulated chip single body 11C, a base plating layer covering the exposed portions of the first front electrode 3, the back electrode 7 and the end face electrode 8, and a second front surface After forming an underlying plating layer that covers the exposed portion of the electrode 4, an external connection layer is formed by applying electrolytic plating of Au, Sn, Cu, or the like so as to cover these underlying plating layers. A first external electrode and a second external electrode (both not shown) having a two-layer structure consisting of connection layers are formed, and the chip resistor 1 as shown in FIG. 1 is completed.

  As described above, in the method of manufacturing the chip resistor 1 according to this embodiment, the double substrate 11A having two strip portions is obtained by first dividing the large substrate 11 and then the double substrate 11A is obtained. The end face electrodes 8 are formed on both divided surfaces of the strip-shaped substrate 11A, and then the double strip-shaped substrate 11A is secondarily divided into two strip-shaped substrates 11B along the first divided groove 12 at the center. Since the substrate 11B is tertiary-divided into individual chips 11C along the second dividing grooves 13, no directionality occurs in the double strip substrate 11A when the end surface electrode 8 is formed. It is possible to eliminate a manufacturing error that the strip-shaped substrate 11B after the secondary division is formed on the wrong end face. In addition, since the end face electrodes 8 can be formed from both the left and right sides of the double strip substrate 11A, the production efficiency can be increased.

  Further, when looking at the strip-shaped substrate 11B after the secondary division, both the surface electrodes 3, 4 and the resistor 5 are formed at positions deviated from the center, but in the double strip-shaped substrate 11A before the secondary division, Since the symmetry of the two strip-shaped portions connected via the central first dividing groove 12 is maintained, the plurality of double strip-shaped substrates 11A are not inclined when the end face electrode 8 is formed by sputtering. It can be aligned in a horizontal posture, and the end face electrodes 8 can be collectively formed by sputtering on the dividing surface of the double strip substrate 11A.

  Of the first and second surface electrodes 3 and 4 forming a pair formed in each chip formation region of the large substrate 11, the first surface electrode 3 straddles the first divided groove 12 that is primarily divided. Since the second surface electrode 4 is formed at a position separated from the first divided groove 12 remaining on the double strip substrate 11A without being divided primarily, it can be mounted by using both soldering and wire bonding. When manufacturing a simple chip resistor 1, the end surface electrode 8 is reliably conducted to the first surface electrode 3 serving as a soldering electrode, and the short circuit of the second surface electrode 4 serving as a wire bonding electrode is reliably eliminated. be able to.

  Further, the set of the surface electrodes 3 and 4 and the resistor 5 formed on the two strip portions of the double strip substrate 11A has a shape symmetrical with respect to the central first divided groove 12, and the first of them is the first. Since the inner second surface electrode 4 facing the dividing groove 12 is formed larger than the outer first surface electrode 3, a wire having a large area is mounted when the chip resistor 1 is mounted on the circuit board 20. The wire 23 can be easily connected to the second surface electrode 4 for bonding.

  In the above embodiment, the groove depths of the first divided grooves 12 formed on the surface of the large-sized substrate 11 are all set to be the same. However, as shown in FIG. The groove depth of the first divided groove 12a may be set larger (deeper) than the groove depth of the first divided groove 12b that is secondarily divided. When such a large substrate 11 is used, when the first divided groove 12a having a larger groove depth is primarily divided to obtain a double strip-shaped substrate 11A from the large substrate 11, the first groove having the smaller groove depth is used. It is possible to prevent the one-divided groove 12b from being accidentally broken.

  Alternatively, as shown in FIG. 8, the first divided grooves 12 a that are primarily divided are formed on the surface of the large substrate 11, and the first divided grooves 12 b that are secondarily divided are formed on the back surface of the large substrate 11. When such a large-sized substrate 11 is used, when the primary division is performed in the opening direction of the front-side first division groove 12a, a force in the closing direction acts on the first division groove 12b on the back surface side. Therefore, it is possible to prevent the first divided groove 12b that is secondarily divided during the first division from being broken.

  In the above embodiment, the manufacturing method of the chip resistor 1 that can be mounted by using both soldering and wire bonding has been described. However, the present invention provides a surface mounting in which end face electrodes are formed on both end faces of an insulating substrate. It is also applicable to type chip resistors. In this case, after forming end face electrodes that are electrically connected to the first surface electrode on both divided surfaces of the double strip substrate, the second surface electrode is formed on the divided surface of the strip substrate obtained by secondary division of the double strip substrate. A conductive end face electrode may be formed.

  In the above embodiment, the primary division to the tertiary division are performed along the grid-like first division grooves 12 and the second division grooves 13 formed on the large substrate 11. It is also possible to perform part or all of the division to tertiary division by dicing or laser scribing. In that case, instead of forming a dividing groove on a large-sized substrate, an expected division line may be set, and division may be performed along the expected division line using dicing or laser scribing.

DESCRIPTION OF SYMBOLS 1 Chip resistor 2 Insulating substrate 3 1st front electrode 4 2nd front electrode 5 Resistor 6 Protective film 7 Back electrode 8 End surface electrode 9 1st external electrode 10 2nd external electrode 11 Large format board 11A Double strip board 11B Strip shape Substrate 11C Single chip 12, 12a, 12b First dividing groove (first dividing line)
13 Second division groove (second division line)
20 Circuit board 21 Wiring pattern 22 Solder 23 Wire

Claims (5)

A large-sized substrate having a large number of first dividing lines and second dividing lines extending in a lattice shape is prepared, and each chip forming region partitioned by the first dividing line and the second dividing line on the surface of the large-sized substrate is prepared. And a step of forming a pair of electrodes spaced apart with a predetermined interval, and a resistor straddling between the two electrodes,
A double substrate in which two strip-shaped portions are connected via the first division lines by primary division of the large substrate on which the electrodes and the resistors are formed along every other first division line. Obtaining a strip substrate;
Forming an end face electrode that is electrically connected to the electrode on both opposing facets of the double strip substrate; and
A step of obtaining a strip-shaped substrate by secondarily dividing the double strip-shaped substrate on which the end face electrodes are formed along the first dividing line;
A step of dividing the strip substrate into a plurality of single chips by performing a third division along the second division line;
A method for manufacturing a chip resistor, comprising:   2. The dividing groove according to claim 1, wherein the first dividing line is a dividing groove formed in the large-sized substrate, and the dividing groove is primarily divided with respect to a groove depth of the dividing groove to be secondarily divided. A method for manufacturing a chip resistor, characterized in that the depth is set large.   2. The division line according to claim 1, wherein the first dividing line is a dividing groove formed in the large-sized substrate, and the dividing groove to be primarily divided is formed on the surface of the large-sized substrate and is secondarily divided. The chip resistor manufacturing method according to claim 1, wherein the dividing groove is formed on a back surface of the large substrate.   4. The electrode according to claim 1, wherein one of the pair of electrodes formed in the chip formation region is formed so as to straddle the first division line that is primarily divided. 5. And the other electrode is formed at a position away from the first division line that is secondarily divided.   5. The two sets of electrodes formed on the double strip substrate according to claim 4, each having a line-symmetric shape with respect to the first dividing line, and of these electrodes, being close to the first dividing line. A method of manufacturing a chip resistor, wherein one electrode is formed larger than a far electrode.