JP4167194B2 - Manufacturing method of chip parts - Google Patents

Description

  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.

  FIG. 6 is a cross-sectional view of a chip resistor generally known from the prior art. A chip resistor 1 shown in FIG. 6 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.

Conventionally, the chip resistor 1 configured as described above is manufactured by a process described below (see, for example, Patent Document 1). 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 groove, 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.
JP-A-6-120013 (page 2-3, FIG. 1)

  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.

  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.

  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.

In order to achieve the above object, in the method of manufacturing a chip resistor according to the present invention, 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, and both ends on one surface of the large substrate Forming a plurality of resistors connected to the electrodes, a protective layer forming step of forming a protective layer so as to cover at least the electrodes on the front and back surfaces of the large substrate, and the protective layer forming step Substrate fixing step of fixing the subsequent large-size substrate on a support base made of a flexible sheet by the adhesive force of the protective layer, and a plurality of primary slits parallel to the large-size substrate fixed on the support base. Forming a primary slit that divides the electrode that connects the adjacent resistors, and connecting the electrodes on the front and back surfaces inside the primary slit by curving the support base; An end face electrode forming step for forming end face electrodes by sputtering, a secondary slit forming step for forming a number of secondary slits extending in a direction orthogonal to the primary slit on the large substrate after the end face electrode forming step, And a component separation step of separating the large substrate from the support base after the next slit forming step to obtain individual components.

  According to the manufacturing method of the chip resistor including each step as described above, after forming a large number of primary slits in a state where a large-sized substrate is fixed on a support base made of a flexible sheet, the support base is curved. Since the end face electrodes are formed by sputtering in a state where the interval between the primary slits is widened, the end face electrodes are formed even if the width dimension between the primary slits becomes very small due to the downsizing of the chip resistor. It can be formed easily and with high accuracy. In addition, since the electrodes on both the front and back surfaces of the large substrate are covered with the protective layer, the end surface electrodes do not wrap around to the electrodes on both the front and back surfaces of the large substrate, and the end surface electrodes can be formed with high accuracy also from this point. .

  In the above configuration, it is preferable that the support table is fixed to the outer peripheral surface of the cylindrical jig in the end face electrode forming step, and the end face electrode is formed by sputtering while rotating the jig. It is preferable to form the secondary slit after returning the support base to a flat shape.

  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.

  In the chip resistor manufacturing method according to the present invention, electrodes and resistors corresponding to individual chip resistors are collectively formed on a large substrate having a predetermined size, and then the large substrate is fixed on a support base. Since the end face electrodes are formed by sputtering in the state where the primary slits are formed and the interval between the primary slits is widened by utilizing the flexibility of the support base, each primary slit is formed along with the downsizing of the chip resistor. Even if the width dimension between them becomes very small, the end face electrodes can be formed easily and with high precision, and the electrodes on both the front and back sides of the large-sized substrate are covered with a protective layer when the end face electrodes are formed. Therefore, the end face electrode does not go around to the electrodes on the front and back sides of the large-sized substrate, and the end face electrode can be formed with high accuracy from this point.

  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. 4 is a plan view showing the manufacturing process of the chip resistor, FIG. 4 is an explanatory view showing an end face electrode forming process in the manufacturing process of the chip resistor, and FIG. 5 is an enlarged view of a main part of FIG.

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.

  Next, the manufacturing process of the chip resistor 11 configured as described above will be described with reference to FIGS.

  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.

  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.

  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.

  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).

  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 the front and back surfaces of the large-sized substrate 12A, and the large-sized substrate 12A is made of polyimide by the adhesive force of the lower protective layer 24 as shown in FIGS. 2 (f) and 3 (f). It fixes on the support stand 25 which consists of flexible sheets, such as (a board | substrate fixing process). 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.

  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 reach the peripheral edge of the large substrate 12A, but a strip-like portion 27 sandwiched between a pair of adjacent primary slits 26 is fixed on the support base 25 by the adhesive force of the lower protective layer 24. Therefore, the large-sized substrate 12 </ b> A having the primary slit 26 is not separated while being held by the support base 25.

  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). In this case, as shown in FIG. 4, the support base 25 is wound and fixed on the outer peripheral surface of the cylindrical jig 28 to widen the interval between the primary slits 26 outward, and the jig 28 is rotated in this state. However, the end face electrode 19 is formed by sputtering nickel chrome (target) in the direction of arrow A. As a result, as shown in FIG. 5, the sputtered film easily goes around the end face P1 of the large-sized substrate 12A (strip-shaped portion 27) inclined with respect to the direction of the arrow A. The film is not formed too thick, and the warping of the large substrate 12A due to the non-uniform film thickness can be prevented. Although omitted in FIGS. 4 and 5, 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. 19 does not reach the front surface electrode 14 and the back surface electrode 18 on both the front and back surfaces of the large substrate 12A.

  Next, after removing the support base 25 from the cylindrical jig 28 and returning it to a flat shape, as shown in FIG. 3 (h), the large substrate 12A is parallel to each other extending in a direction orthogonal to the primary slits 26 by dicing. A plurality of secondary slits 29 are formed, and the large substrate 12A is subdivided into a large number of single chips 30 surrounded by the primary slits 26 and the secondary slits 29 (secondary slit forming step).

  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.

  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 a large number of primary slits 26 are formed in a state in which the large-sized substrate 12A is fixed on the support base 25 made of a flexible sheet. Since the end face electrode 19 is formed by sputtering in a state where the space between the primary slits 26 is widened by winding and fixing them on the cylindrical jig 28, each primary slit 26 is reduced along with the downsizing of the chip resistor 11. Even if the width dimension between them becomes very small, the end face electrode 19 can be formed easily and with high accuracy. Moreover, since the surface electrode 14 and the back surface electrode 18 are covered with the upper protective layer 23 and the lower protective layer 24, respectively, when the end surface electrode 19 is formed, the end surface electrode 19 is formed on the front and back surfaces of the large substrate 12A. 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.

  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.

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 rear 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 .

  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.

It is sectional drawing of the chip resistor which concerns on the example of embodiment of this invention. It is sectional drawing which shows the manufacturing process of this chip resistor. It is a top view which shows the manufacturing process of this chip resistor. It is explanatory drawing which shows the end surface electrode formation process in the manufacturing process of this chip resistor. It is a principal part enlarged view of FIG. It is sectional drawing of the chip resistor which concerns on a prior art 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 stand 26 Primary slit 27 Strip-shaped portion 28 Cylindrical jig 28
29 Secondary slit 30 Single chip

Claims (4)

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 layer forming step of forming a protective layer so as to cover at least the electrodes on both the front and back surfaces of the large substrate;
A substrate fixing step of fixing the large-sized substrate after the protective layer forming step on a support base made of a flexible sheet by the adhesive force of the protective layer ;
A primary slit forming step of dividing the electrode that connects the adjacent resistors by forming a large number of primary slits parallel to each other on the large substrate fixed on the support;
An end face electrode forming step of forming an end face electrode by sputtering the end face electrode that connects the electrodes on both the front and back sides inside the primary slit by curving the support base;
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 separating the large substrate from the support base after the secondary slit forming step to obtain individual components;
A method of manufacturing a chip resistor comprising: 2. The chip resistor according to claim 1, wherein the support table is fixed to an outer peripheral surface of a cylindrical jig in the end face electrode forming step, and the end face electrode is formed by sputtering while rotating the jig. method of manufacturing a vessel. 3. The method of manufacturing a chip resistor according to claim 1, wherein the secondary slit is formed after the support base is returned to a flat shape in the secondary slit forming step. 4. 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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