JPH07135101A - Chip component and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a chip component, in which the adhesion of an electrode layer to edges of a ceramic chip is improved by making the chip in such manner that it includes its edges having a random combination of fired areas and cut areas. CONSTITUTION:A ceramic green sheet 10 is provided both with longitudinal slits 10b, cut through from the front side to the reverse side, and with transverse grooves 10a. The green sheet is fired to form a ceramic substrate 11, which has transverse slits 11a corresponding to the slits 10a and longitudinal slits 11b corresponding to the slits 10b. A front electrode layer 13, a resistor layer 14 and a back electrode layer are formed on each unit area 12 defined by longitudinal and transverse slits. The resistor layer is trimmed to obtain a desired resistance value, and it is covered with a protective layer 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip-shaped electronic component and a method for manufacturing the same, and more specifically, it uses a ceramic substrate, and divides the ceramic substrate and forms an electrode layer on the divided surface. The present invention relates to a chip-shaped electronic component such as a chip resistor and a chip capacitor, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a chip resistor, which is one of chip-shaped electronic components, is manufactured by forming a plurality of vertical and horizontal slits on the surface of an unfired ceramic sheet at a depth of about half the thickness of the unfired ceramic sheet. After the grooves are embossed to form a grid pattern, the grooves are fired and then, as shown in FIGS. 4 and 5,
A ceramic substrate 1 having vertical and horizontal slit grooves 1a and 1b on its surface is obtained. As shown in FIG. 6, a surface electrode layer 2 and a ceramic substrate 1 are provided for each unit region defined by the vertical and horizontal slit grooves 1a and 1b on the surface of the ceramic substrate 1. After the resistor layer 3 is formed, the resistance value is adjusted by trimming, the protective layer 4 covering the resistor layer 3 is formed, and then the surface electrode layer 2 is formed as shown in FIG. The ceramic substrate 1 is divided into a plurality of rod-shaped pieces 1 ′ along the vertical slit groove 1a on one side, and as shown in FIG. 8, both longitudinal side surfaces 1′a, 1′b of the rod-shaped pieces 1 ′ are formed. Then, the side surface electrode layer 5 is formed on the substrate, and then the rod-shaped piece 1'is divided along the lateral slit groove 1b to obtain a chip shape.

Generally, as a method of forming the side surface electrode layers 5 on both side surfaces 1'a, 1'b in the longitudinal direction of the rod-shaped piece 1 ', for example, a conductor paste such as Ag paste or Ag-Pd paste is printed and fired. Then, a method of forming a metal layer is adopted. By the way, the above-mentioned protective layer 4 and side electrode layer 5
Is formed after the resistance value of the resistor layer 3 is adjusted, and therefore, when the protective layer 4 and the side surface electrode layer 5 are provided by high temperature firing, the oxidation state of the metal components in the resistor layer 5 is changed. There is a problem that the resistance value of the resistor layer 5 deviates slightly from the adjusted value. This problem has become one of the problems to be solved in the chip resistor as the precision of electronic parts has been required more and more recently. Therefore, in order to cope with the current situation, the side surface electrode layer 5 is formed as a resin-based electrode layer using a conductive resin paste, or a metal layer such as Ni—Cr or Ti is formed by a sputtering or vapor deposition method. Then, by forming at a relatively low temperature, the deviation of the resistance value is reduced as much as possible.

[0004]

However, according to the above conventional method, the ceramic substrate 1 on which the surface electrode layer 2, the resistor layer 3 and the protective layer 4 are formed is divided along the vertical slit groove 1a, When the side surface electrode layers 5 are formed on the longitudinal side surfaces 1'a, 1'b of the obtained rod-shaped piece 1 ', the longitudinal side surfaces 1'a, 1'b of the rod-shaped piece 1'shown in FIG.
As shown in FIG. 3, the vertical slit groove 1a includes a side wall portion X and a fractured portion Y that is actually divided. Since the side wall portion X is in contact with the outside air during firing of the unfired ceramic sheet, firing proceeds. On the other hand, the surface thereof is relatively rough, but on the other hand, the breaking portion Y is a smooth mirror surface due to the characteristics of the ceramic when it is broken, and both side surfaces 1'in the longitudinal direction of such a rod-shaped piece 1 '. When the side surface electrode layer 5 is formed on a and 1'b, there is a problem that the side surface electrode layer 5 is peeled off due to low adhesion of the side surface electrode layer 5 at the portion of the broken portion Y which is a mirror surface. This problem occurs in the case of a side electrode layer having a relatively thin thickness formed by the above-mentioned sputtering or vapor deposition method or in the case of a resin-based side electrode layer using a conductive resin paste containing a resin having poor adhesion to ceramics. , And it is remarkable especially when a conductive resin paste is used.

Therefore, in order to solve the above problem, Japanese Patent Publication No.
In JP-A-36921, as shown in FIG. 10, a long groove (slit-shaped hole) 6a penetrating from the front surface to the back surface of the unfired ceramic sheet 6 is formed as a vertical slit groove by punching, and the lateral slit groove 6b is formed by the above method. A method of forming by stamping has been proposed in the same manner as in. Thus, by forming the long groove 6a in which the slit groove on the side of the side electrode layer is completely punched out, substantially all of the side wall of the long groove 6a can be brought into contact with the outside air when firing the unfired ceramic sheet. The side wall of the vertical slit groove of the ceramic substrate becomes a rough surface, and the adhesion of the side surface electrode layer can be improved.

However, the method described in the above publication is
As shown in FIG. 11, in order to form a long punched through long groove 6a in the unfired ceramic sheet 6 and fire it to provide a vertical slit groove in the ceramic substrate 7, a through vertical hole in the obtained ceramic substrate 7 is formed. Slit groove 7
With respect to a, the shrinkage rate of the unfired ceramic sheet 6 due to the firing is partially different, so that distortion occurs in a drum shape or the like, and the ceramic substrate 7 warps. When the above-mentioned distortion, warpage, etc. occur, a deviation of the formation position occurs in the forming process of the surface electrode layer, the resistor layer, the protective layer, etc., leading to a decrease in workability, and the obtained chip resistor has a variation in size. As a result, there is a problem that the dimensional accuracy is lowered and the appearance is also deteriorated.

The present invention solves the above problems, and in a chip-shaped electronic component in which a ceramic substrate is used and an electrode layer is formed on the divided surface of the ceramic substrate, the electrode layer and the divided surface of the ceramic substrate are in close contact with each other. It is an object of the present invention to provide a highly reliable chip-shaped electronic component having improved reliability.

[0008]

In order to achieve the above object, the present invention is arranged such that at least a side surface of a ceramic substrate on which an electrode layer is formed has a rough surface portion and a mirror surface portion randomly mixed. Further, among the slit slits for division provided in the unfired ceramic sheet, at least the slit groove on the electrode layer (side electrode layer) formation side is formed by cutting. That is, the present invention relates to the following method. A chip-shaped electronic component having an electrode layer provided on a side face of a ceramic substrate, wherein the side face is formed of a fracture surface and a firing surface that are randomly mixed. The step of making a plurality of cuts in the unfired ceramic sheet from the front surface to the back surface of the unfired ceramic sheet, the step of firing the unfired ceramic sheet to form a ceramic substrate, and the ceramic substrate corresponding to the notch A method of manufacturing a chip-shaped electronic component, comprising: a step of dividing along a portion to be formed; and a step of providing an electrode layer on a division surface by the division. The method for manufacturing a chip-shaped electronic component as described above, wherein the notch is provided leaving a peripheral edge of the surface of the unfired ceramic sheet. The method for manufacturing a chip-shaped electronic component as described above or in which the electrode layer is provided using a conductive resin paste. The method for producing a chip-shaped electronic component as described above or in which the electrode layer is provided by sputtering or vapor deposition.

[0009]

Since the electrode layer is provided on the side surface of the ceramic substrate in which the fired surface and the fractured surface are mixed irregularly, the electrode layer is firmly adhered at the site of the fired surface. . Therefore, the electrode layer is substantially uniformly and firmly adhered to the side surface, and the obtained chip-shaped electronic component is excellent in the adhesiveness of the electrode layer and has high reliability.

On the other hand, when a plurality of incisions extending from the front surface to the back surface of the unsintered ceramic sheet are made in the unsintered ceramic sheet, the force that tends to narrow the gaps between the cut surfaces due to the incisions. Acts, and the cut surfaces are in partial contact with each other. When the unfired ceramic sheet is fired in this state to form a ceramic substrate, the non-contact portion between the cut surfaces due to the cuts becomes a rough surface because firing progresses while contacting the outside air, and thus the cut surface of the obtained ceramic substrate becomes The corresponding portion is in a partially continuous (fused) state (see FIG. 3). Further, in the case where bubbles are trapped due to partial contact between the cut surfaces of the unfired ceramic sheet, firing is performed in order to make the thermal expansion coefficient different between the bubbles and the ceramic substrate. When a ceramic substrate is used as the ceramic substrate, the stress generated by the expansion of the bubbles concentrates on the portion along the cut surface, so that the firing proceeds while the crack partially occurs. Therefore, along with the growth of the cracks, firing proceeds while air enters the cracks, the portion where the cracks occur becomes a rough surface, and the portion corresponding to the cut surface in the obtained ceramic substrate is partially continuous. It will be in the state of doing.

When the thus-formed ceramic substrate is divided along the portion corresponding to the cut surface where the above-mentioned cut is made, the fracture surface becomes a smooth mirror surface, and as a result, the divided surface becomes a rough surface portion (fired surface). The mirror surface portion (broken surface) is irregularly mixed. When the electrode layer is provided on this divided surface, the electrode layer can be formed with high adhesion to the ceramic substrate due to the unevenness of the rough surface portion.

Further, as described above, the unfired ceramic sheet is fired in a state where the cut surface where the notch is formed is partially continuous, so that the obtained ceramic substrate is almost free from warpage and distortion. It is.

[0013]

EXAMPLES The features of the present invention will be described in more detail below by showing examples with a chip resistor as an example, but the present invention is not limited thereto. The chip resistor is provided on both sides of the chip-shaped ceramic substrate, which has a fractured surface and a firing surface in which the opposite left and right side surfaces are randomly mixed and a front surface side of the chip-shaped ceramic substrate. A pair of front surface electrode layers,
A pair of back surface electrode layers provided on the back surface side of the ceramic substrate corresponding to the front surface electrode layers, a resistor layer provided so as to extend between the pair of front surface electrode layers, and the resistor layers are covered. Protective layers, side surface electrode layers provided on each of the left and right side surfaces of the chip-shaped ceramic substrate and electrically connecting the front surface electrode layer and the back surface electrode layer, and are provided so as to cover exposed portions of these electrode layers. And a plated layer.

The chip resistor can be manufactured, for example, as follows. First, as shown in FIG. 1, a plurality of substantially V-shaped slit grooves 10a extending in the lateral direction and having a depth of about half the thickness of the unfired ceramic sheet 10 are arranged in parallel on the surface of the unfired ceramic sheet 10. A plurality of notches 10b are formed by embossing and subsequently reach the back surface from the front surface of the unfired ceramic sheet 10 so as to be substantially orthogonal to the slit grooves 10a extending in the horizontal direction by using a cutting blade or the like in parallel in the vertical direction. Put in. The term "cut" as used herein means to make a cut so that the cut surface of the unfired ceramic sheet due to the cut has a portion that is substantially in contact and a portion that is not in contact. At this time, at least the notch 10b of the slit groove 10a and the notch 10b is formed in the peripheral edge 10 of the unfired ceramic sheet 10.
It is preferable to provide extra c, so that the minimum strength of the ceramic substrate obtained by subsequent firing can be more reliably maintained. In addition, the slit groove 10a and the notch 1
Either 0b may be provided first, or both may be provided at the same time. Furthermore, the slit groove 10a extending in the lateral direction is provided.
Alternatively, the cut may be made in the same manner as the cut 10b in the vertical direction.

Next, the slit groove 10a is formed as described above.
And the unfired ceramic sheet 10 provided with the notches 10b are fired to have a ceramic substrate 11 having lateral slit grooves 11a and vertical slit grooves 11b corresponding to the slit grooves 10a and notches 10b as shown in FIGS. 2 and 3. As shown in FIG. 9, the lateral slit groove 11 is obtained.
unit area 1 defined by a and the vertical slit groove 11b
The front electrode layer 13 and the resistor layer 14 and the back electrode layer are formed for each two, and the resistance value is adjusted by trimming as necessary, and the protective layer 15 is formed so as to cover the resistor layer 14.

Then, as shown in FIG. 10, the ceramic substrate 1 on which the layers 13, 14, and 15 are formed as described above.
1 is divided along the vertical slit groove 11b to obtain a rod-shaped piece 1
1'is obtained, and as shown in FIG. 11, side surface electrode layers 16 are provided on both longitudinal side surfaces 11'a, 11'b (divided surfaces) of this rod-shaped piece 11 '. The side surface electrode layer 16 is formed by printing a conductive paste such as Ag paste or Ag-Pd paste.
It may be provided by a firing method, for example, a sputtering or vapor deposition method using a metal such as Ni-Cr or Ti, or a method of applying and curing a conductive resin paste such as an Ag-resin system. Among these forming methods of the side surface electrode layer 16, when the method of forming by the sputtering and vapor deposition method and the method of using the conductive resin paste, which have a relatively weak adhesion with the ceramic substrate, are applied, the above-mentioned adhesion is improved. The effect is great, and it is extremely effective especially when a conductive resin paste is used.

Then, the rod-shaped piece 11 'is divided along the lateral slit groove 11a into a chip shape, and a plating layer, for example, Ni, is formed so as to cover the front surface electrode layer 13, the back surface electrode layer and the side surface electrode layer 16. A chip resistor is obtained by providing a plating layer and a solder plating layer.

[0018]

As described above, according to the present invention,
The adhesiveness of the electrode layer to the divided surface of the ceramic substrate can be extremely improved, and a highly reliable chip-shaped electronic component can be provided. Further, since it is possible to obtain a ceramic substrate with high dimensional accuracy that is almost free from deformation such as warpage and distortion, for example, in the case of a chip resistor, a surface electrode layer, a resistor layer, a protective layer, etc. It is possible to significantly reduce the occurrence of misalignment of the formation position when forming each layer and improve workability.

[Brief description of drawings]

FIG. 1 is a partial perspective view of an unfired ceramic sheet according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view illustrating a lateral slit groove of a ceramic substrate obtained by firing the unfired ceramic sheet of FIG.

FIG. 3 is an enlarged sectional view illustrating vertical slit grooves of a ceramic substrate obtained by firing the unfired ceramic sheet of FIG.

FIG. 4 is a partial top view of a conventional ceramic substrate for manufacturing a chip resistor.

5 is an enlarged sectional view taken along line I-I of FIG. 4. FIG.

FIG. 6 is a partial top view showing a state where a surface electrode layer, a resistor layer and a protective layer are provided on a ceramic substrate.

FIG. 7 is a schematic top view for explaining how the ceramic substrate is divided into rod-shaped pieces.

FIG. 8 is an enlarged top view showing a state in which side surface electrode layers are provided on both side surfaces along the longitudinal direction of the rod-shaped piece.

FIG. 9 is an explanatory view showing a surface state of a side surface of a rod-shaped piece obtained by a conventional method.

FIG. 10 is a partial top view of an unfired ceramic sheet according to another conventional method.

11 is an enlarged top view of a ceramic substrate obtained by firing the unfired ceramic sheet of FIG.

[Explanation of symbols]

 10 Unfired Ceramic Sheet 10a Slit Groove 10b Notch 11 Ceramic Substrate 11a Horizontal Slit Groove 11b Vertical Slit Groove 11 'Rod-shaped Piece 11'a, 11'b Dividing Surface 12 Unit Area 13 Surface Electrode Layer 14 Resistor Layer 15 Protective Layer 16 Side Surface Electrode layer

Claims (5)

[Claims] 1. A chip-shaped electronic component in which an electrode layer is provided on a side surface of a ceramic substrate, wherein the side surface is formed of a fracture surface and a firing surface which are randomly mixed. parts. 2. A step of making a plurality of cuts in a green ceramic sheet from the front surface to the back surface of the green ceramic sheet, a step of firing the green ceramic sheet to form a ceramic substrate, and the ceramic substrate A method for manufacturing a chip-shaped electronic component, comprising: a step of dividing along a portion corresponding to the cut, and a step of providing an electrode layer on a division surface by the division. 3. The method for manufacturing a chip-shaped electronic component according to claim 2, wherein the notch is provided while leaving a peripheral edge of the unfired ceramic sheet. 4. The method for manufacturing a chip-shaped electronic component according to claim 2, wherein the electrode layer is provided using a conductive resin paste. 5. The method for producing a chip-shaped electronic component according to claim 2, wherein the electrode layer is provided by sputtering or vapor deposition.