JP4067923B2 - Manufacturing method of chip resistor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a chip resistor, and more particularly to a method of manufacturing a chip resistor suitable for use when the external dimensions are reduced.
[0002]
[Prior art]
FIG. 4 is a sectional view of a conventionally known chip resistor. A chip resistor 1 shown in FIG. 4 has an insulating substrate 2 made of alumina or the like, and a resistor is provided on the insulating substrate 2. A body 3 and a pair of surface electrodes 4 overlapping each other on both ends of the resistor 3 are formed. The resistor 3 is covered with a glass coat layer 5, and the glass coat layer 5 is further covered with an overcoat layer 6 made of an epoxy resin or the like. The glass coat layer 5 and the overcoat layer 6 function as a protective film for the resistor 3. A pair of back surface electrodes 7 are formed at both ends corresponding to the front surface electrode 4 on the back surface of the insulating substrate 2, and the front surface electrode 4 and the back surface electrode 7 are respectively bridged on both end surfaces of the insulating substrate 2. An end face electrode 8 is formed. The front electrode 4 and the back electrode 7 are formed by screen printing or the like using a paste mainly composed of silver (Ag), and the end electrode 8 is formed by sputtering nickel chrome (Ni / Cr), for example. . The front electrode 4, the back electrode 7 and the end electrode 8 constitute a base electrode layer of the chip resistor 1, and a nickel (Ni) plating layer 9 is formed by plating the base electrode layer at the final stage of the manufacturing process. The base electrode layer is covered with a two-layered plating layer of a solder (SN / Pb) plating layer 10. The plating layers 9 and 10 are for preventing electrode cracking and improving the reliability of soldering, and a tin (Sn) plating layer may be used instead of the solder plating layer.
[0003]
Conventionally, the chip resistor 1 configured as described above is manufactured by the steps described below. That is, first, a large-sized substrate in which dividing grooves extending vertically and horizontally are formed at positions that divide each chip region, and a large number of front surface electrodes 4 and back surface electrodes 7 corresponding to the individual chip resistors 1 are formed on the large-sized substrate. At the same time, after the resistor 3 is formed between the adjacent surface electrodes 4, the glass coat layer 5 and the overcoat layer 6 are sequentially formed on each resistor 3. Next, after dividing the large substrate along one dividing groove (primary division) to obtain a large number of strip-shaped divided pieces, the strip-shaped divided pieces are stacked on both end surfaces along the respective longitudinal directions. The end face electrode 8 is formed. Thereafter, each strip-shaped divided piece is divided into chip sizes (secondary division) along the other divided grooves, and finally, nickel (Ni) and solder (SN / Pb) plating layer 10 is applied, whereby FIG. A large number of chip resistors 1 as shown in FIG. As a conventional example related to this type of technology, for example, Patent Document 1 is cited.
[0004]
[Patent Document 1]
JP-A-6-120013 (page 2-3, FIG. 1)
[0005]
[Problems to be solved by the invention]
By the way, in recent years, chip resistors have been miniaturized along with miniaturization of various electronic devices. For example, an ultra-small chip resistor having a planar outer dimension of 0.6 mm × 0.3 mm has been realized. There is also a need for miniaturized chip resistors.
[0006]
However, in the above-described conventional manufacturing method, the end face electrode is formed on the end face of the strip-shaped divided piece obtained by first dividing the large-sized substrate, and the primary step of dividing the large-sized substrate into the strip shape as a pre-process for forming the end face electrode. Since division is required, if the width of the strip-shaped divided piece becomes very small as the chip resistor is miniaturized, it becomes difficult to primarily divide the large substrate into strip-shaped divided pieces. In addition, even if a large number of strip-shaped divided pieces can be obtained from a large-sized substrate, the mechanical strength of the strip-shaped divided pieces decreases as the width dimension becomes smaller. Thus, when the end face electrodes are formed on both end faces, there arises a problem that the strip-like divided pieces are carelessly cracked. Further, as chip resistors are miniaturized, slight positional misalignment of a plurality of strip-shaped divided pieces superimposed on each other becomes a cause of defective end face electrodes, making it difficult to form end face electrodes with high accuracy. The problem that becomes.
[0007]
The present invention has been made in view of the actual situation of the prior art, and an object of the present invention is to provide a chip resistor that can easily and highly accurately form an end face electrode even if the external dimensions are reduced. There is.
[0008]
[Means for Solving the Problems]
In order to achieve the above-described object, in the method of manufacturing a chip resistor according to the present invention, an electrode forming step for forming a large number of electrodes on both the front and back surfaces of a large substrate of a predetermined size, and both ends on one surface of the large substrate. Forming a resistor connected to the electrodes, a protective film forming step of forming a protective film so as to cover the resistor, and the front and back of the large substrate after the protective film forming step a protective layer forming step of forming respectively at least the upper protective layer to cover the electrode and the lower protective layer on both sides, fixing the large substrate after the protective layer forming step on the support base by the adhesive force of the lower protective layer a substrate fixing step of, said electrodes connecting the resistor adjacent to form a number of primary slits parallel to each other from the outside of the upper protective layer in the large-sized substrate, which is fixed on the support table A primary slit forming step for dividing, an end surface electrode forming step for forming end surface electrodes for connecting the electrodes on the front and back surfaces inside the primary slit by sputtering, and the primary slit in the large substrate after the end surface electrode forming step. A secondary slit forming step for forming a number of secondary slits extending in a direction orthogonal to the vertical slit, and removing the upper protective layer and the lower protective layer after the secondary slit forming step to remove the large substrate from the support base. And a component separation step for separating and obtaining individual components.
[0009]
According to the manufacturing method of the chip resistor including each step, a large number of primary slits are formed in a state where the large-sized substrate is fixed on the support base by the adhesive force of the lower protective layer , and spaces in these primary slits are formed. Since the end face electrode is formed by sputtering, the end face electrode is easily and accurately formed even if the width dimension between the primary slits becomes very small as the chip resistor becomes smaller. can do. In addition, since the electrodes on both the front and back sides of the large substrate are covered with the upper protective layer and the lower protective layer, the end surface electrode does not reach the electrodes on the front and back surfaces of the large substrate. Can be formed.
[0011]
In the above configuration, the electrode and resistor may be either thick film formation such as screen printing or thin film formation such as sputtering, but when forming the electrode and resistor thick film, use wax as a protective layer. In the primary slit forming step, the chipping of the electrode can be prevented, which is preferable. On the other hand, when the electrode and the resistor are formed into a thin film, the protective layer on the side covering the electrode to be connected to the resistor may be a resist or a wax, but the protective layer on the side for fixing the large substrate on the support base is bonded. It is preferable to use a tape.
[0012]
In the above configuration, both ends of the primary slit may reach the periphery of the large substrate in the primary slit forming step, but at least one end of the primary slit is connected to the periphery of the large substrate through the connecting portion. It is more preferable that the strips between the adjacent primary slits are fixed on the support base and connected to the peripheral edge of the large-sized substrate.
[0013]
In the above configuration, a laser or a water jet can be used as a processing means for forming the primary slit and the secondary slit, but it is preferable to form the primary slit and the secondary slit by dicing.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
1 is a cross-sectional view of a chip resistor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a manufacturing process of the chip resistor, and FIG. It is a top view which shows the manufacturing process of this chip resistor.
[0015]
A chip resistor 11 shown in FIG. 1 overlaps a resistor 13 made of ruthenium oxide or the like on both sides of the resistor 13 on the surface side of an insulating substrate 12 mainly composed of alumina (Al ₂ O ₃ ). A pair of surface electrodes 14 and a glass coat layer 15 and an overcoat layer 16 that cover the resistor 13 are formed. The overcoat layer 16 is made of an epoxy resin or the like, and the glass coat layer 15 and the overcoat layer 16 function as a protective film 17 for the resistor 13. Further, a pair of back surface electrodes 18 are formed on both end portions corresponding to the front surface electrode 14 on the back surface side of the insulating substrate 12, and the front surface electrode 14 and the back surface electrode 18 are respectively formed on both side end surfaces of the insulating substrate 12. Are formed. The front electrode 14 and the back electrode 18 are formed by using a screen printing or the like with a paste mainly composed of Ag or Ag-Pd, and the end electrode 19 is formed by sputtering nickel chrome (Ni / Cr). Is. The front electrode 14, the back electrode 18 and the end electrode 19 constitute a base electrode layer of the chip resistor 11, and nickel (Ni) plating is performed by plating the base electrode layer in the final stage of the manufacturing process described later. The underlying electrode layer is covered with a two-layered plating layer 22 of a layer 20 and a solder (SN / Pb) plating layer 21. The plating layer 22 (20, 21) is for preventing electrode cracking and improving the reliability of soldering, and a tin (Sn) plating layer can be used instead of the solder plating layer. It is.
[0016]
Next, the manufacturing process of the chip resistor 11 configured as described above will be described with reference to FIGS.
[0017]
First, as shown in FIGS. 2 (a) and 3 (a), a large-sized substrate 12A for preparing multiple pieces is prepared. The large substrate 12A serves as the insulating substrate 12 of the chip resistor 11. In FIGS. 2 and 3, only one or a plurality of chip regions are shown. A large number of chip resistors 11 can be obtained collectively.
[0018]
Next, as shown in FIG. 2 (b) and FIG. 3 (b), Ag or Ag-Pd paste is screen-printed on both the front and back surfaces of the large substrate 12A, and this is baked at a temperature of about 850 ° C. A large number of front surface electrodes 14 and back surface electrodes 18 corresponding to the individual chip resistors 11 are formed (electrode formation step). Either the front electrode 14 or the rear electrode 18 may be formed first, but the front electrode 14 is arranged in a matrix on the front side of the large substrate 12A, and the rear electrode 18 is also formed in a matrix on the rear side of the large substrate 12A. Arranged.
[0019]
Next, as shown in FIGS. 2 (c) and 3 (c), a resistor paste such as ruthenium oxide is screen-printed on the surface side of the large substrate 12A and baked, so that the X direction in FIG. 3 (b). Each of the resistors 13 is formed between a pair of surface electrodes 14 adjacent to each other (resistor forming step). It should be noted that either the resistor 13 or the surface electrode 14 may be formed first, and the surface electrode 14 adjacent to both ends of the resistor 13 may be connected.
[0020]
Next, as shown in FIGS. 2 (d) and 3 (d), a glass paste is screen-printed and fired so as to cover each resistor 13, thereby forming a strip shape along the Y direction in FIG. 3 (b). A glass coat layer 15 is formed extending in the direction. Thereafter, as shown in FIGS. 2 (e) and 3 (e), a resin paste such as epoxy is screen-printed on the glass coat layer 15 and heated and cured to cover the glass coat layer 15 and form a belt-like shape. An overcoat layer 16 extending in the direction of 2 is formed, and a protective film 17 having a two-layer structure for protecting each resistor 13 is formed (protective film forming step).
[0021]
Thus, after forming the front and back double-sided electrodes 14 and 18 corresponding to many chip resistors 11, the resistor 13, and the protective film 17 (the glass coat layer 15 and the overcoat layer 16) collectively on the large substrate 12A, An upper protective layer 23 and a lower protective layer 24 are formed on both the front and back sides of the large substrate 12A (protective layer forming step) . As shown in FIGS. 2 (f) and 3 (f), the adhesive strength of the lower protective layer 24 is as follows. Thus, the large substrate 12A is fixed on the support base 25 (substrate fixing step). Both the upper protective layer 23 and the lower protective layer 24 are made of wax, and are formed to have a uniform thickness on both the front and back surfaces of the large substrate 12A. The support base 25 is made of, for example, an alumina substrate, but a glass substrate or a resin substrate may be used instead of the alumina substrate.
[0022]
Next, as shown in FIGS. 2G and 3G, a plurality of primary slits 26 parallel to each other are formed on the large substrate 12A by dicing, and the front electrode 14 and the back electrode 18 are formed by these primary slits 26. Each pair is divided into two along the Y direction in FIG. 3B (primary slit forming step). Both ends of these primary slits 26 do not reach the peripheral edge portion of the large-sized substrate 12A, and a connecting portion 27 having no slit is secured between both ends of the primary slit 26 and the peripheral edge portion of the large-sized substrate 12A. The strip-shaped portion 28 sandwiched between the pair of primary slits 26 is held on the large-sized substrate 12 </ b> A via the connecting portion 27. However, since the strip-like portion 28 is fixed on the support base 25 by the adhesive force of the lower protective layer 24, one end or both ends of the primary slit 26 may be extended to the peripheral portion of the large substrate 12A.
[0023]
Next, as shown in FIG. 2 (h), nickel chromium (Ni / Cr) is sputtered on the inner surface of the primary slit 26, so that the end surfaces of the surface electrode 14 and the back electrode 18 exposed in the primary slit 26 are separated from each other. A bridging end face electrode 19 is formed (end face electrode forming step). When the end face electrode 19 is formed, the front face electrode 14 and the back face electrode 18 are covered with the upper protective layer 23 and the lower protective layer 24, respectively. The end surface electrode 19 can be formed with high accuracy while maintaining the dimensional accuracy of the front surface electrode 14 and the back surface electrode 18 in screen printing.
[0024]
Next, as shown in FIG. 3 (h), a plurality of parallel secondary slits 29 extending in a direction perpendicular to the primary slits 26 are formed on the large substrate 12A by dicing, and the large substrate 12A is formed with the primary slits 26. Subdivided into a large number of single chips 30 surrounded by the secondary slits 29 (secondary slit forming step).
[0025]
Thereafter, by cleaning the upper protective layer 23 and the lower protective layer 24, each chip unit 30 provided on the large substrate 12A is peeled off from the support base 25 (part separation step). By applying electrolytic plating to the base electrode layer to form a nickel (Ni) plating layer 20 and a solder (SN / Pb) plating layer 21, a large number of chip resistors 11 as shown in FIG. 1 are obtained.
[0026]
The chip resistor 11 manufactured in this way has the front and back double-sided electrodes 14 and 18 corresponding to the chip resistor 11 taken in large numbers on a large substrate 12A of a predetermined size, the resistor 13, and the protective film 17 (glass coating layer). 15 and the overcoat layer 16) are collectively formed, and then an upper protective layer 23 and a lower protective layer 24 are formed on both the front and back surfaces of the large substrate 12A , and then the large substrate 12A is formed by the adhesive force of the lower protective layer 24. A large number of primary slits 26 are formed in a state in which the chip resistor 11 is fixed on the support base 25, and the end face electrodes 19 are formed by sputtering using the spaces in the primary slits 26. Therefore, the chip resistor 11 can be reduced in size. Accordingly, even if the width dimension between the primary slits 26 becomes very small, the end face electrode 19 can be formed easily and with high accuracy. Since the surface electrode 14 and the back electrode 18 are covered with the upper protective layer 23 and the lower protective layer 24, respectively, when the electrode 19 is formed, the end face electrode 19 wraps around to the front electrode 14 and the back electrode 18 on both the front and back surfaces of the large substrate 12A. In other words, the end face electrode 19 can be formed with high accuracy while maintaining the dimensional accuracy in screen printing of the front electrode 14 and the back electrode 18.
[0027]
The chip resistor 11 is formed by forming a thick film of the resistor 13, the front electrode 14, and the back electrode 18. Since the upper protective layer 23 and the lower protective layer 24 are made of wax, a large substrate is formed by dicing. It is possible to prevent the front electrode 14 and the back electrode 18 from being chipped when the primary slit 26 is formed in 12A. Further, since both ends of the primary slit 26 do not reach the peripheral edge portion of the large substrate 12A, and a connecting portion 27 without a slit is secured between both ends of the primary slit 26 and the peripheral portion of the large substrate 12A, the primary slit 26 The strip-shaped portion 28 sandwiched between the slits 26 can be reliably held on the large-sized substrate 12A via the connecting portion 27, and the accuracy of the end face electrode 19 can be increased also from this point.
[0028]
In the above embodiment, the thick film type chip resistor 11 in which the resistor 13, the surface electrode 14, and the back electrode 18 are formed thick has been described. However, the resistor, the surface electrode, and the back electrode are formed by sputtering or the like. It can also be applied to a thin film type chip resistor formed into a thin film. In this case, since there is no possibility that the front electrode 14 and the back electrode 18 are lost due to dicing when the primary slit 26 is formed, a resist may be used instead of wax as the upper protective layer 23, and the large-sized substrate 12A is supported on the support base. It is preferable to use an adhesive tape instead of wax as the lower protective layer 24 fixed on the surface 25.
[0029]
In the above embodiment, dicing is exemplified as the processing means for forming the primary slit 26 and the secondary slit 29. However, a laser or a water jet can be used instead of dicing.
[0030]
【The invention's effect】
The present invention is implemented in the form as described above, and has the following effects.
[0031]
After forming electrodes and resistors corresponding to individual chip resistors on a large substrate of a predetermined size, an upper protective layer and a lower protective layer are formed on both the front and back surfaces of the large substrate , respectively. A large number of primary slits were formed with the large-size substrate fixed on the support base by the adhesive force of the end face, and the end face electrodes were formed by sputtering using the space in these primary slits. Even if the width dimension between the primary slits becomes very small as a result of this, the end face electrodes can be formed easily and with high accuracy, and the electrodes on both the front and back sides of the large substrate are formed at the time of forming the end face electrodes. are covered by the upper protective layer and the lower protective layer is not the end surface electrode from flowing to the both sides of the electrodes of the large-area substrate, to form an end face electrode from this point with high precision Kill.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a chip resistor according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a manufacturing process of the chip resistor.
FIG. 3 is a plan view showing a manufacturing process of the chip resistor.
FIG. 4 is a cross-sectional view of a chip resistor according to a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Chip resistor 12 Insulating board | substrate 12A Large format board 13 Resistor 14 Front surface electrode 15 Glass coat layer 16 Overcoat 17 Protective film 18 Back surface electrode 19 End surface electrode 22 Plating layer 23 Upper protective layer 24 Lower protective layer 25 Support base 26 Primary slit 27 Connecting portion 28 Strip portion 29 Secondary slit 30 Single chip

Claims (5)

An electrode forming step of forming a large number of electrodes in a matrix on both front and back surfaces of a large substrate of a predetermined size;
A resistor forming step of forming a large number of resistors whose both ends are connected to the electrodes on one surface of the large substrate,
A protective film forming step of forming a protective film so as to cover the resistor;
A protective layer forming step of forming an upper protective layer and a lower protective layer so as to cover at least the electrodes on both the front and back surfaces of the large substrate after the protective film forming step ;
A substrate fixing step of fixing the large-sized substrate after the protective layer forming step on a support base by an adhesive force of the lower protective layer ;
A primary slit forming step of dividing the electrode connecting the adjacent resistors into two by forming a large number of primary slits parallel to each other from the outside of the upper protective layer on the large substrate fixed on the support;
An end face electrode forming step of forming an end face electrode for connecting the electrodes on both the front and back surfaces by sputtering inside the primary slit;
A secondary slit forming step of forming a number of secondary slits extending in a direction orthogonal to the primary slit in the large substrate after the end face electrode forming step;
A component separation step of removing the upper protective layer and the lower protective layer after the secondary slit forming step to separate the large substrate from the support to obtain individual components,
A method of manufacturing a chip resistor comprising: 2. The method of manufacturing a chip resistor according to claim 1 , wherein the electrode and the resistor are formed in a thick film, and the protective layer is a wax. 2. The chip resistor according to claim 1 , wherein the electrode and the resistor are formed into a thin film, and the protective layer on the side for fixing the large substrate on the support base is an adhesive tape. Production method. 4. The method of manufacturing a chip resistor according to claim 1 , wherein at least one end of the primary slit is connected to a peripheral edge of the large substrate through a connecting portion. 5. 5. The method of manufacturing a chip resistor according to claim 1 , wherein the primary slit and the secondary slit are formed by dicing.

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