Chip parts

Abstract

To provide a chip component appropriate for downsizing.SOLUTION: A chip resistor comprises: an insulation substrate 1 in a rectangular parallelepiped shape; a belt-like resistive element 2 formed in a length direction on a front face of the insulation substrate 1; a pair of front electrodes 3 formed in both ends in the length direction on the front face of the resistive element 2; an insulating protective layer 4 covering the entire front face of the insulation substrate 1 including the resistive element 2 and the front electrode 3; a pair of end face electrodes 5 formed in both ends in the length direction of the insulation substrate 1 so as to connect end faces of the resistive element 2, the front electrode 3 and the protective layer 4; and a pair of outer electrodes 6 mounted on front faces of the end face electrodes 5. A cross-sectional shape of the front electrode 3 is substantially triangular shape in which an end face side has a maximum height, and an end face shape of the end face electrode 5 is a substantially square shape.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a surface-mount type chip component such as a chip resistor. [Background technology]

[0002] A chip resistor, which is an example of a chip component, is composed of a rectangular insulating substrate, a pair of front electrodes arranged opposite each other at a predetermined distance on the surface of the insulating substrate, a resistor bridging the pair of front electrodes, an insulating protective film covering the resistor, a pair of back electrodes arranged opposite each other at a predetermined distance on the back surface of the insulating substrate, and a pair of end electrodes formed on both ends of the insulating substrate so as to bridge the front and back electrodes, and the outer surfaces of the end electrodes are covered with external electrodes formed by plating.

[0003] A chip resistor configured in this manner is surface-mounted on a circuit board by applying solder paste to a land on the circuit board, placing the external electrode on the land with the back electrode facing downwards, and then melting and solidifying the solder paste in this state.

[0004] Here, the external electrodes and internal end surface electrodes soldered to the lands are usually formed in a U-shape so that they are exposed on three surfaces (top, end, and bottom) of the chip resistor, excluding both side surfaces. Meanwhile, as disclosed in Patent Document 1, a chip resistor is also known in which the end surface electrodes are formed in a cap shape on both ends of the insulating substrate, so that it can be mounted on a circuit board with any of the four surfaces (top, bottom, and both side surfaces) facing in that direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-45861 Summary of the Invention [Problem to be solved by the invention]

[0006] The chip resistor described in Patent Document 1 has front electrodes connected to both ends of the resistor exposed from each of the short and long edge faces of the insulating substrate, and cap-shaped edge electrodes connected to the edge faces of the front electrodes exposed from these three faces, thereby improving the connection reliability between the front electrodes and the edge electrodes. However, the miniaturization of chip components such as chip resistors has been progressing rapidly in recent years, and for example, when the external dimensions of chip resistors are reduced to 0201 size (long side 0.250 mm, short side 0.125 mm), the contact area between the front electrodes and the edge electrodes is significantly reduced, causing a problem of reduced connection reliability between the resistor and the front electrodes.

[0007] The present invention has been made in view of the current state of the prior art, and an object of the present invention is to provide a chip component that is suitable for miniaturization. [Means for solving the problem]

[0008] In order to achieve the above object, the chip part of the present invention comprises a rectangular parallelepiped insulating substrate, a strip-shaped conductive film formed on a main surface of the insulating substrate from end to end along the longitudinal direction, a pair of electrodes formed on both longitudinal ends of the surface of the conductive film, an insulating protective layer formed from end to end of the insulating substrate and covering the entire main surface of the insulating substrate including the conductive film and both electrodes, and a pair of cap-shaped end surface electrodes provided on both longitudinal ends of the insulating substrate and connected to the conductive film, the electrodes, and each end surface of the protective layer, the conductive film is a resistor, and the protective layer is composed of a glass coating layer covering the resistor and a resin coating layer covering the glass coating layer, The cross-sectional shape of the electrode is a substantially triangular shape with the end face side being the maximum height, and the end face shape of the end face electrode is a substantially square, and the electrode is connected to the end face electrode on a total of three faces, namely, the end face in the longitudinal direction of the insulating substrate and both side faces adjacent to the end face. and the length is shorter than the length of the end electrode when viewed from above. It is characterized by the following.

[0009] In the chip component configured in this way, the conductive film which is the functional element Resistor as are formed in a strip shape on an insulating substrate, ResistorThe cross-sectional shape of the electrode formed on the insulating substrate is a substantially triangle with the end face side being the maximum height, and the electrode is connected to the end face electrode on three faces in total: the end face in the longitudinal direction of the insulating substrate and both sides adjacent to the end face. Therefore, even if the external dimensions of the chip component are reduced, the cap-shaped end face electrode can be used. Resistor The insulating substrate can be made to cover the entire main surface of the insulating substrate. The formed protective layer is composed of a glass coating layer covering the resistor and a resin coating layer covering the glass coating layer, and the resin coating layer The end surface of the end electrode covering the end of the At the same time, the length of the electrode is shorter than the length of the end electrode when viewed from above. Therefore, The resin coating layer exposed between the pair of end electrodes is not affected by the thickness of the resistor and the electrode stack. As a result, the surface of the resin coating layer located on the outermost layer is made smoother. It is possible to realize an ultra-small chip component having a substantially square prism shape with excellent planarity.

[0010] In chip components having the above configuration, the conductive film may be a conductor with a resistance value of approximately zero ohms, such as a jumper chip, but in the case of a chip resistor in which the conductive film is a resistor, it is preferable that the protective layer be composed of a glass coating layer that covers the resistor and a resin coating layer that covers this glass coating layer.

[0011] In this case, the glass coating layer is formed to cover the surface of the resistor sandwiched between both electrodes and to have a thickness thinner than the maximum height of the electrodes, and the resin coating layer covers the glass coating layer and both electrodes and is formed from one end of the insulating substrate to the other. Since a pair of electrodes is exposed from both ends of the glass coating layer, when forming a trimming groove in the resistor to adjust the resistance value during the manufacture of a chip resistor, a probe can be placed on the pair of electrodes to measure the resistance value of the resistor, and a laser beam can be irradiated from above the glass coating layer to form a trimming groove in the resistor. Furthermore, since the resin coating layer, which is the outermost layer of the protective layer, is formed from one end of the insulating substrate to the other, it is easy to form cap-shaped end surface electrodes that connect to the resistor, the electrodes, and each end surface of the resin coating layer. [Effects of the Invention]

[0013] According to the present invention, the external dimensions of the chip component can be reduced while ensuring the connection reliability between the conductive film of the end face electrode and the electrode. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view of a chip resistor according to an embodiment of the present invention; [Figure 2] FIG. 2 is a plan view of the chip resistor of FIG. 1 as seen from above. [Figure 3]FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 4 is a detailed view of part A in FIG. 3. [Figure 5] FIG. 3 is a cross-sectional view taken along line VV in FIG. [Figure 6] 3A to 3C are plan views showing the manufacturing process of the chip resistor. [Figure 7] 3A to 3C are cross-sectional views showing a manufacturing process of the chip resistor. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0016] FIG. 1 is an oblique view of a chip resistor according to an embodiment, FIG. 2 is a plan view of the chip resistor of FIG. 1 seen from above, FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2, FIG. 4 is a detailed view of part A of FIG. 3, and FIG. 5 is a cross-sectional view taken along line VV of FIG. 2.

[0017] 1 to 5, the chip resistor according to this embodiment is mainly composed of a rectangular parallelepiped insulating substrate 1, a resistor 2 formed in a strip shape along the longitudinal direction on the surface of the insulating substrate 1, a pair of front electrodes 3 formed on both longitudinal ends of the surface of the resistor 2, an insulating protective layer 4 covering the entire surface of the insulating substrate 1 including the resistor 2 and the front electrode 3, a pair of end electrodes 5 formed on both longitudinal ends of the insulating substrate 1 so as to connect to the end faces of the resistor 2, the front electrode 3, and the protective layer 4, and a pair of external electrodes 6 attached to the surfaces of these end electrodes 5. In the following description, the longitudinal direction of the insulating substrate 1 is referred to as the X direction, and the lateral direction of the insulating substrate 1 perpendicular to the X direction is referred to as the Y direction.

[0018] The insulating substrate 1 is a ceramic substrate whose main component is alumina, and is obtained by dicing a large-sized substrate (described later) along the primary division predicted lines and secondary division predicted lines that extend in a grid pattern to produce a large number of insulating substrates 1.

[0019] The resistor 2 is formed by screen-printing a resistive paste such as ruthenium oxide on the surface of the insulating substrate 1, followed by drying and baking, and both longitudinal ends of the resistor 2 are exposed from both X-direction end faces of the insulating substrate 1. Although not shown, the resistor 2 has a trimming groove formed therein for adjusting the resistance value.

[0020] The pair of front electrodes 3 are formed by screen-printing an Ag-based paste onto the resistor 2, followed by drying and firing, and are positioned so as to overlap both longitudinal ends of the resistor 2. As is clear from Figures 3 and 4, the cross section of the front electrodes 3 is a substantially triangular shape with its maximum height at the end face in the X direction of the insulating substrate 1. Note that the front electrodes 3 are exposed not only from the end face in the X direction of the insulating substrate 1, but also from both end faces in the Y direction of the insulating substrate 1.

[0021] The protective layer 4 has a two-layer structure consisting of a glass coating layer 7 that covers the resistor element 2 and a resin coating layer 8 that covers the glass coating layer 7. The glass coating layer 7 is formed by screen-printing a glass paste onto the resistor element 2 and then drying and baking it, and this glass coating layer 7 covers the resistor element 2 and is exposed from both end faces in the Y direction of the insulating substrate 1. The thickness of the glass coating layer 7 is set thinner than the maximum height dimension of the front electrode 3, so that the glass coating layer 7 is not exposed from both end faces in the X direction of the insulating substrate 1, and the inclined faces of the front electrode 3 are exposed from both end faces of the glass coating layer 7 in the X direction.

[0022] Resin coating layer 8 is formed by screen-printing an epoxy resin paste onto glass coating layer 7 and then heat-curing it, and is made of a transparent or translucent resin material. Resin coating layer 8 is formed so as to cover the entire surface of insulating substrate 1, including front electrodes 3 and glass coating layer 7. Therefore, as shown in FIG. 1 , both ends of resin coating layer 8 in the Y direction, together with glass coating layer 7, are exposed from both side surfaces of insulating substrate 1.

[0023] The pair of end electrodes 5 are formed by dip-coating and heat-curing Ag paste or Cu paste. These end electrodes 5 are formed in a cap shape, covering both end faces of the insulating substrate 1 in the X direction, the upper surface of the resin coating layer 8, and the lower and both side surfaces of the insulating substrate 1. As a result, the end electrodes 5 are connected to the end faces of the resistor 2 in the X direction and to the surface electrodes 3 exposed from the three end faces of the insulating substrate 1. Note that before the end electrodes 5 are formed, the chip element has an external shape that is approximately a square prism, and the cap-shaped end electrodes 5 are formed on both longitudinal ends of this chip element. That is, the insulating substrate 1 has a rectangular parallelepiped shape whose thickness (height in FIG. 1 ) is shorter than its width (length in the Y direction). However, by laminating a protective layer 4 (glass coating layer 7 and resin coating layer 8) of a predetermined thickness so as to cover the entire surface of the insulating substrate 1, a square prism-shaped chip element is formed with equal width and thickness.

[0024] Although not shown, the pair of end electrodes 5 are covered with external electrodes, which are formed by electroplating the surfaces of the end electrodes 5 with Ni, Sn, or the like.

[0025] Next, a method for manufacturing the chip resistor configured as described above will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a plan view showing the manufacturing process of the chip resistor, and Fig. 7 is a cross-sectional view showing the manufacturing process of the chip resistor.

[0026] First, a large-sized ceramic substrate 10A from which a large number of insulating substrates 1 are to be formed is prepared. While no primary or secondary division grooves are formed in this large-sized substrate 10A, predicted primary division lines L1 and predicted secondary division lines L2 are set on the large-sized substrate 10A as dicing positions when the large-sized substrate 10A is diced into a large number of chip elements in a later process. In other words, in FIG. 6, if the left-right direction of the large-sized substrate 10A is the X direction and the up-down direction is the Y direction, predicted primary division lines L1 extending in the Y direction and predicted secondary division lines L2 extending in the X direction are set in a grid pattern on the large-sized substrate 10A, and each of the squares separated by these predicted division lines L1 and L2 corresponds to a chip formation area.

[0027] Then, by screen-printing a resistor paste such as ruthenium oxide on the surface of the large-sized substrate 10A and drying and baking it, a plurality of resistors 2 are formed in a strip-like shape extending in the X direction across the primary division predicted lines L1 in the region sandwiched between the secondary division predicted lines L2 (resistor formation process) as shown in Figures 6(a) and 7(a). Note that Figure 6 shows the large-sized substrate 10A as seen in plan, and Figure 7 shows a cross section of one chip formation region in Figure 6 taken along the longitudinal direction of the resistor 2.

[0028] Next, an Ag-based paste is printed on the surface of the large-sized substrate 10A, dried, and baked to form a plurality of front electrodes 3 facing each other at a predetermined interval in the X direction at positions that overlap the predicted primary division line L1 on each resistor 2, as shown in Figures 6(b) and 7(b) (front electrode formation process). These front electrodes 3 are printed in a rectangular shape with a relatively thick film (4 μm or more), and the film thickness gradually decreases from the center to both ends in the X direction due to the viscosity of the paste.

[0029] Next, a glass paste is screen-printed, dried, and baked to form a transparent glass coating layer 7 that covers the resistor element 2 exposed between the pair of front electrodes 3 (glass coating layer formation process), as shown in Figures 6(c) and 7(c). This glass coating layer 7 is formed so as to extend in a strip shape in the Y direction that intersects with the longitudinal direction of the resistor element 2, straddling the predicted secondary division line L2.

[0030] Next, a measurement probe (not shown) is brought into contact with a pair of surface electrodes 3 exposed from both ends of the glass coating layer 7, and while measuring the resistance value of the resistor 2 between the two surface electrodes 3 in this state, laser light is irradiated from above the glass coating layer 7 to form trimming grooves (not shown) in the resistor 2 and adjust the resistance value (resistance value adjustment process).

[0031] Next, an epoxy resin paste containing a white pigment is screen-printed onto the front electrode 3 and the glass coating layer 7 and then heat-cured to form a translucent resin coating layer 8 that covers the entire chip formation area of ​​the large-format substrate 10A, including the front electrode 3 and the glass coating layer 7, as shown in Figures 6(d) and 7(d) (resin coating layer formation process). The glass coating layer 7 and the resin coating layer 8 form a two-layer protective layer 4, and because this protective layer 4 is a laminate of the transparent glass coating layer 7 and the translucent resin coating layer 8, the positions of the internal front electrode 3 and resistor 2 can be visually observed through the protective layer 4.

[0032] Next, the large-format substrate 10A is fixed to a base 11 made of a hard material such as ceramics via an adhesive 12. The large-format substrate 10A is then cut with a dicing blade 13 along the primary division lines L1 and the secondary division lines L2 to form through-slits 14, which are lattice-shaped in plan view and extend partway through the base 11, as shown in FIGS. 6(e) and 7(e) (dicing process). The front electrode 3, which is formed so as to straddle the primary division lines L1, is cut by dicing along the primary division lines L1. Therefore, the cross-section of the short printed front electrode 3 is approximately triangular, with the cut surface along the primary division lines L1 as its maximum height. Furthermore, both ends of the front electrode 3 extending from the resistor 2 in the Y direction are cut by dicing along the secondary division lines L2, exposing the cut surfaces of the front electrode 3 on three sides of the through-slits 14.

[0033] In this dicing process, the positions of the internal surface electrodes 3 and resistors 2 can be visually observed through the protective layer 4 that covers the entire surface of the large-format substrate 10A, so the dicing positions (the predicted primary division lines L1 and the predicted secondary division lines L2) can be accurately determined. Note that the predicted primary division lines L1 and the predicted secondary division lines L2 are imaginary lines set on the large-format substrate 10A, and as mentioned above, no primary division grooves or secondary division grooves corresponding to the predicted division lines are formed on the large-format substrate 10A.

[0034] Next, the adhesive 12 is washed away and the fixing base material 11 is peeled off from the large-sized substrate 10A, thereby obtaining a large number of chip elements 10B having approximately the same external shape as the chip resistors, as shown in Figures 6(f) and 7(f).

[0035] Subsequent steps are not shown, but next, a conductive paste such as Ag paste or Cu paste is dip-applied to the end faces of chip element 10B and heated to harden, thereby forming cap-shaped end electrodes that wrap around from both longitudinal end faces of chip element 10B to predetermined positions on both lateral end faces (end electrode formation step).At this time, because the external shape of chip element 10B is a roughly regular square prism, the end electrodes that wrap around to the four sides of chip element 10B form rectangular shapes of the same size on the surface of protective layer 4 and the remaining three ceramic faces.

[0036] Finally, each chip element 10B is electroplated with Ni, Sn, or the like to form external electrodes that cover the end surface electrodes (external electrode forming step), completing a chip resistor as shown in FIGS.

[0037] As described above, in the chip resistor according to this embodiment, the resistor 2, which is the functional element, is formed in a strip shape on the insulating substrate 1, and the cross-sectional shape of the front electrodes 3 formed on both ends of the resistor 2 is a substantially triangular shape with the end face side being the maximum height. This allows the cap-shaped end electrodes 5 to be reliably connected to the end faces of the resistor 2 and the front electrodes 3 even when the external dimensions of the chip resistor are reduced. Furthermore, the protective layer 4 is formed so as to cover the entire surface of the insulating substrate 1, including the resistor 2 and the front electrodes 3, and the end faces of the end electrodes 5 covering the ends of this protective layer 4 have a substantially square shape. This allows for an ultra-compact, approximately flat resistor. Positive A square pillar-shaped chip component can be realized.

[0038] Furthermore, in the chip resistor of this embodiment, the protective layer 4 is made up of a two-layer structure of a glass coating layer 7 and a resin coating layer 8, and the thickness of the glass coating layer 7 is set thinner than the maximum height dimension of the surface electrodes 3, so that the pair of surface electrodes 3 are exposed from both ends of the glass coating layer 7.Therefore, in the resistance value adjustment process for adjusting the resistance value of the resistor 2, a probe is placed on the pair of surface electrodes 3 to measure the resistance value of the resistor 2, and laser light is irradiated from above the glass coating layer 7 to form a trimming groove in the resistor 2.

[0039] Furthermore, in the chip resistor of this embodiment, the surface electrode 3 is exposed not only from the longitudinal end faces of the insulating substrate 1, but also from both short end faces of the insulating substrate 1, and the end face electrodes 5 are connected to the surface electrode 3 on these three faces, thereby improving the connection reliability between the surface electrode 3 and the end face electrodes 5.

[0040] In the above embodiment, the present invention has been described as being applied to a chip resistor in which the conductive film serving as the functional element is a resistor. However, the conductive film may be something other than a resistor, such as a conductor with a resistance value of approximately zero ohms, such as a jumper chip. In this case, since there is no need to adjust the resistance value of the conductive film, the protective layer may have a single-layer structure consisting of only a resin coating layer. [Explanation of symbols]

[0041] 1. Insulating substrate 2 resistors 3. Surface electrode 4 protective layer 5 End electrode 6 External electrode 7 Glass coating layer 8 Resin coating layer 10A large board 10B Chip element 11 Fixed base material 12 Adhesive 13 Dicing Blade 14 Through slit

Claims

1. a rectangular parallelepiped insulating substrate; a strip-shaped conductive film formed on a main surface of the insulating substrate from end to end along a longitudinal direction; a pair of electrodes formed on both longitudinal ends of the surface of the conductive film; an insulating protective layer formed from one end of the insulating substrate to the other end of the insulating substrate, covering the entire main surface of the insulating substrate including the conductive film and both electrodes; a pair of cap-shaped end electrodes provided at both longitudinal ends of the insulating substrate and connected to the conductive film, the electrode, and the protective layer; Equipped with the conductive film is a resistor, and the protective layer is composed of a glass coating layer covering the resistor and a resin coating layer covering the glass coating layer, The cross-sectional shape of the electrode is a substantially triangular shape with the end face side being the maximum height, and the end face shape of the end face electrode is a substantially square shape, the electrodes are connected to the end surface electrodes on three surfaces in total, namely, the end surface in the longitudinal direction of the insulating substrate and both side surfaces adjacent to the end surface, and are shorter than the end surface electrodes in top view; A chip component characterized by:

2. The glass coating layer covers the surface of the resistor sandwiched between the electrodes and is formed to a thickness thinner than the maximum height of the electrodes, the resin coating layer covers the glass coating layer and both electrodes and is formed from one end to the other of the insulating substrate; 2. The chip part according to claim 1.

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