JPH10189305A - Angular plate type chip resistor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angular plate type chip resistor which does not require front/rear discrimination, can cope with high-density packing, and can be manufactured at a low cost. SOLUTION: Paired internal electrodes 2 are provided in a ceramic coating body 10 at nearly the intermediate position of the body 10 in the thickness direction and, at the same time, a film- or thin film-like resistor 3 which connects the electrodes 2 to each other is provided between the electrodes 2. Therefore, the front and rear surfaces of the electrodes 2 and resistor 3 are coated with the coating body 10. The coating body 10 is composed of a laminated ceramic body formed by piling up two green ceramic sheets upon another and baking the laminated green sheets and provided with terminal electrodes 4 connected to the internal electrodes 2 on both the front and rear surfaces of the body 10 at both end sections of the body 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a square plate type chip resistor having a structure that does not require front and back selection, capable of supporting high-density mounting, and capable of being produced at low cost, and a method of manufacturing the same.

[0002]

2. Description of the Related Art At present, a square plate type chip resistor manufactured by using a fired alumina substrate as a base substrate,
An Ag electrode, a resistor, a protective glass and the like are patterned thereon by a screen printing technique, and after baking, the resistance value is adjusted, and then the base substrate is divided into a bar shape in which a plurality of resistors are arranged in a row. (Break) apply the terminal electrode,
Furthermore, it is commercialized by dividing (breaking) it into chip shapes to be individual resistors and plating the terminal electrodes.

[0003]

However, the above-described prior art has the following problems.

(1) Dozens of types of screen masks (pastes that become electrodes, resistors, etc., with dimensions in the X-axis direction and Y-axis direction changed according to the finished dimensions after firing of an alumina substrate used as a base substrate) It is necessary to prepare a mask for screen printing in advance, which increases the cost. The reason for this is that the alumina substrate has snap grooves in the X and Y-axis directions on the assumption that the chip is finally broken into chips. Because it changes.

(2) There is still a problem in the control technology with reproducibility of the material of the alumina substrate and the firing process, and it is necessary to secure the shape and dimensions of the alumina substrate after firing (for example, distortion in the X and Y directions, substrate warpage, etc.). There is a limit to the maximum substrate area (suppressed within a predetermined range). For example, the current length is 1mm and width is 0.5m
In the case of a chip-shaped product (1005 shape) having a thickness of 0.5 mm and a thickness of 0.5 mm, the processing substrate size is about 50 mm square to 80 mm square at the maximum.

(3) Since there are many firing processes, the manufacturing process becomes complicated and productivity is poor. For example, Ag electrode firing,
Resistor firing, trimming glass firing, protective coat firing,
Terminal electrode baking and the like are required.

(4) Due to the essential problem of the screen printing technique, a resistance adjusting step is inevitably required because the resistor thickness variation is ± 10% to 20%.

(5) The shape of the final product is not stable due to the step of breaking the snapped alumina substrate from a bar to a chip. As a result, the board assembly process (the process of mounting various devices on the printed circuit board)
This causes the product mounting accuracy and mounting reliability to deteriorate. In addition, the necessity of a chip resistor front-and-back selection mechanism in a mounting machine for mounting the chip resistor on the substrate is also a factor that leads to an increase in cost (prior art products have a resistor and a protective coat facing upward. To be mounted on the board). Furthermore, since the processing size of the product to be processed changes as the process progresses, the position is determined and alignment is required, which lowers the production efficiency.

(6) The conventional method for forming terminal electrodes is AgP
Because d-type electrode paste is applied by rubber transfer method,
With the product shape of the alumina substrate after the break, there is a limit in stabilizing the electrode coating thickness and its variation.
As a result, with respect to various product designs using the chip resistor, the pattern design of the printed circuit board in consideration of the terminal electrode coating thickness is inevitable, so that the allowable design range is reduced.

(7) In a product having a conventional structure, a solder fillet generated in a terminal electrode portion after mounting on a substrate of various devices becomes large. As a result, there is a limit in minimizing the dimension between lands on the mounting board side (compatible with high-density mounting).

[0011] A first object of the present invention is to solve the above problems,
It is an object of the present invention to provide a square-plate type chip resistor that does not require front and back selection, can be used for high-density mounting, and can be produced at low cost.

A second object of the present invention is to reduce the number of manufacturing steps,
An object of the present invention is to provide a method of manufacturing a square chip resistor capable of manufacturing a square chip resistor at a low cost while improving production efficiency.

Other objects and novel features of the present invention will be clarified in embodiments described later.

[0014]

In order to achieve the above object, a square chip resistor according to the present invention is provided with a film or a thin plate-like resistor between internal electrodes, and a table of the internal electrodes and the resistor is provided. A ceramic covering body is provided to cover the back surface, and terminal electrodes connected to the internal electrodes are provided at both ends of the covering body.

In the above-mentioned square-plate type chip resistor,
It is also possible to form a concave groove penetrating in the front and back directions on both end surfaces of the cover, and to connect the exposed portion of the internal electrode and the terminal electrode on the inner surface of the concave groove.

According to the method of manufacturing a square plate type chip resistor of the present invention, a first conductive paste serving as an internal electrode is provided on a first unfired ceramic sheet serving as a cover, and a first conductive paste is provided between the first conductive pastes. Providing a film or a thin plate-shaped resistor, laminating a second unfired ceramic sheet to be a coating on the first unfired ceramic sheet, and interposing the first unfired ceramic sheet between the first and second unfired ceramic sheets. A step of forming an unfired ceramic sheet laminate sandwiching a first conductor paste and the resistor; and forming a through hole or a groove through the laminate at a position penetrating the first conductor paste. Providing a second conductive paste to be a terminal electrode on the front and back surfaces of the laminate and the inner surface of the through hole or groove; and at least one of the resistors and the at least one
Cutting the laminate so as to include the first conductive paste on both sides of each of the plurality of resistors, separating the laminate into chips, and then firing the laminate chip.

In the method for manufacturing a square plate type chip resistor, the resistive ink serving as the resistor may be attached between the first conductive paste on the first unfired ceramic sheet by an ink jet method. Good.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing a square chip resistor according to the present invention;

Referring to FIG. 1, the structure of a completed square plate type chip resistor will be described first. The square-plate type chip resistor 1 is provided with a pair of internal electrodes 2 at a substantially intermediate position in a thickness direction of a ceramic coating 10 and a film or thin plate resistor 3 connecting the internal electrodes to each other. The front and back surfaces of the internal electrode 2 and the resistor 3 are covered with a ceramic covering 10. As is apparent from a manufacturing method described later, the ceramic coating 10 is a ceramic laminate obtained by laminating and laminating two unfired ceramic sheets. Then, terminal electrodes 4 connected to the internal electrodes 2 are provided on the front and back surfaces of both ends of the cover 10.

The internal electrodes 2 are formed by simultaneously firing a conductor paste of Ag or the like and a laminate of unfired ceramic sheets to be the cover 10, and are located at both ends inside the cover 10.

The film or thin plate-shaped resistor 3 is formed by depositing, for example, a resistive ink of a ruthenium oxide-based material on the inner surface of one of the unfired ceramic sheets, and is simultaneously fired with the unfired ceramic sheet laminate serving as the coating 10. It was done.

On both end surfaces of the cover 10, concave grooves 5 (shape obtained by dividing a through hole into two) penetrating in the front and back directions are formed, and the terminal electrodes 4 extending on the inner surface of the concave grooves 5 are formed. Is connected to the exposed portion 2a of the internal electrode 2 from the cover. The lower layer of the terminal electrode 4 is formed by applying a conductor paste such as an Ag-based material to a laminate of unfired ceramic sheets serving as the cover 10 and firing the same simultaneously with the unfired ceramic sheet. It is formed by plating of Sn, Pb-Sn, Ni or the like for ensuring.

Next, the manufacturing process shown in FIG. 2 and FIGS.
A method for manufacturing a square plate type chip resistor will be described with reference to FIGS.

First, in a sheet forming step # 1 shown in FIG. 2, a ceramic material such as an alumina-based material which can be fired at a low temperature (850 ° C. to 890 ° C.) is formed into a green sheet (unfired ceramic sheet) with a thickness of several hundred μm. Base material. In the electrode printing and drying step # 2, an Ag-based conductor paste 21 to be the internal electrode 2 (for example, an Ag electrode) of FIG. 1 is patterned on the base material 20 by screen printing as shown in FIG. , Coated) and dried. Here, in order to simultaneously form a large number of square plate type chip resistors in the vertical and horizontal directions of the base material, the conductive paste 21 is formed in a rectangular shape at regular intervals. Thereafter, in a resistor formation step # 3, a resistor layer 22 that becomes the film or thin plate-shaped resistor 3 of FIG. 1 is formed so as to bridge (crossover) between the conductor pastes 21 that become the internal electrodes. Both ends of the resistor layer 22 partially overlap the conductor pastes 21 located on both sides of the resistor layer 22.

Conventionally, the resistor layer has also been patterned by screen printing, but it has been difficult to control the variation in thickness due to large thickness variations. Therefore, in this manufacturing method, an ink jet direct drawing method in which ink is transferred using a piezoelectric actuator element is employed. As the resistive ink,
A ruthenium oxide-based material is mixed with a binder, a solvent, a dispersant, and the like, and the viscosity is adjusted to 10 cp (centi-poise) before use. With this method, the thickness variation of the resistor layer can be controlled by ±
This makes it possible to reduce the resistance value to about 1%, so that the resistance value adjusting step can be omitted depending on the product type.

The area S defined by the imaginary line in FIG. 3 indicates an area corresponding to one of the square plate type chip resistors.
2 is applied.

After the resistor layer 22 is provided on the base material 20 in a predetermined pattern, an upper sheet material laminating step # 4 is executed, and the base material 2 is placed on the base material 20 as shown in FIG.
The same material (low-temperature sintering alumina-based material) as in Example 0 is overcoated with the same thickness (several 100 μm). In other words,
A ceramic green sheet having the same material and the same thickness is laminated as the upper sheet material 23. As a result, a laminate 30 of ceramic green sheets in which the front and back surfaces of the conductor paste 21 and the resistor layer 22 serving as the internal electrodes are covered with the base member 20 and the upper sheet member 23 serving as the ceramic covering member.

Thereafter, in the gold stamping step # 5, the laminate 30
Is cut and punched by a metal mold so that a predetermined size suitable for processing in a subsequent step is obtained. The laminated body 30 after this punching process has a dimension about several tens times that of a square plate type chip resistor both vertically and horizontally.

Then, a terminal electrode drilling step # 6 is performed with the block-shaped laminated body 30 still. That is, electrical connection (contact) with the conductive paste 21 serving as an internal electrode
Is formed as shown in FIG. The terminal electrode hole 31 is a through hole penetrating the laminate 30 at a position penetrating the conductor paste 21 serving as an internal electrode. The method of forming the terminal electrode hole 31 is punching using a die or laser (YA).
G, excimer laser, etc.).
Efficient through-hole formation is possible by processing with a YAG laser (pulse oscillation). Note that the terminal electrode hole 31 is divided into two in a later step to form the concave groove 5 in FIG.

Then, the front terminal electrode printing and drying process # 7,
The back terminal electrode printing, drying step # 8, and terminal electrode paste injecting step # 9 are sequentially performed. That is, front terminal electrode printing,
In the drying step # 7, an Ag-based conductor paste 32 serving as an upper surface of the terminal electrode is patterned by screen printing (printing and applying in a predetermined pattern) on the laminate 30 after the formation of the terminal electrode holes 31 as shown in FIG. ) And dry. Next, in the back terminal electrode printing and drying step # 8, similarly, a conductive paste 32 of Ag or the like to be the lower surface portion of the terminal electrode is patterned (printed and applied in a predetermined pattern) by screen printing and dried. Then, in the terminal electrode paste injecting step # 9, an electrode material (for example, an Ag-based conductor paste 32) that can be co-fired with the conductor paste 21 serving as the internal electrode.
Is injected into the terminal electrode hole 31 through a mask so as to make contact with the internal electrode. However, if the paste injection into the terminal electrode holes 31 is performed simultaneously in the front terminal electrode printing and drying step # 7 or the back terminal electrode printing and drying step # 8, the terminal electrode paste injection step # 9 is performed independently. It is not necessary to execute as

Thereafter, a cutting step # 10 is applied to the laminated body 30 after the application of the conductive paste 32 to be the terminal electrode 4 in FIG.
And a cutting line C that divides the terminal electrode hole 31 into two and a cutting line D that is orthogonal to the cutting line C, each including one resistor layer 22 and a conductor serving as an internal electrode on both sides of the one resistor layer 22 It is cut so as to include the paste 21 and separated into individual pieces of the laminated chip (the state before firing of the finished product in FIG. 1).

Then, an electrode, resistor, and base material co-firing step # 11 is performed, and a conductor paste serving as internal electrodes and terminal electrodes, a resistor layer 22, a base material 20 which is an alumina-based ceramic green sheet as a base material, and Upper sheet material 23
At the same time. As a result, as shown in FIG. 1, a film or thin plate resistor 3 is provided between the pair of internal electrodes 2, and a ceramic coating 10 covering the front and back surfaces of the internal electrode 2 and the resistor 3 is provided. A square chip resistor having the lower portion of the terminal electrode 4 connected to the internal electrode 2 at both ends of the body 10 is obtained. Since the terminal electrode hole 31 is divided into two in the cutting step # 10, it appears as a concave groove 5 in which the end face extension 4a of the terminal electrode 4 is formed in each square plate type chip resistor.

Lastly, in order to ensure electrical connection at the time of mounting, a plating step # 12 is performed, and Ni, Sn, Pb
-Plating such as Sn is applied on the lower layer portion of the terminal electrode 4 to produce a product.

The materials such as ceramic green sheets made of an alumina-based material, Ag-based internal electrodes, resistor layers, and Ag-based terminal electrodes, etc., must be fired or shrunk in order to perform simultaneous firing at a time. It is desirable to optimize the expansion coefficient and firing profile.

According to this embodiment, the following effects can be obtained.

(1) In the square chip resistor 1, the front and back surfaces of the internal electrode 2 and the resistor 3 are covered with the ceramic covering 10 with the same thickness. There is no need to distinguish between front and back when mounting. For this reason, the structure of the mounting machine for mounting the chip resistance value on the substrate is simplified.

(2) Terminal electrode 4 of square plate type chip resistor 1
Is provided on the inner surface of the concave groove 5 on the front and back surfaces and both end surfaces of the cover 10, but can be provided on the inner surface of the side surface portion, and therefore, the variation in the dimension in the width direction can be reduced. . In this case, since the outer dimension accuracy of the product is determined by the cutting accuracy, the dimensional accuracy of the product is improved. The terminal electrode width is determined by the screen printing accuracy. For example, length 2
mm, 1.25mm width chip shape product (2012 shape), the product outer dimension variation is 2.0mm in the length direction
± 0.05mm, and the terminal electrode width is 0.4mm ±
The thickness can be 0.05 mm, and the variation in the electrode coating thickness does not cause a problem in the product structure.

(3) Since the solder fillet generated at the terminal electrode portion after soldering to various printed circuit boards is almost contained within the external dimensions of the product, the land size and the land-to-land size on the mounting board side of various devices are further minimized. (Compatible with high-density mounting). Also, regarding various device designs,
0.08m on both sides as terminal electrode width of square plate type chip resistor
Since there is no pattern design in consideration of m (terminal electrodes are also attached to side surfaces in the conventional product), the degree of freedom in device design can be improved by several percent from the current state.

(4) Since a conductive paste and a resistor layer to be used as an electrode of Ag type or the like are formed on a ceramic green sheet of alumina type or the like, if a screen mask for screen printing is one type for forming an electrode, By baking after cutting into individual products, variations in firing shrinkage can be minimized.

(5) Instead of using a conventional calcined alumina substrate, the maximum processing substrate size must be within the acceptable range (± 20 μm) of the screen printing accuracy in order to manufacture the substrate in a green sheet state. Thus, it is possible to process up to about 150 mm square to 200 mm square. Therefore, the number of products can be increased.

(6) Simultaneous firing of a low-temperature fired ceramic material such as an alumina-based material, an internal electrode such as an Ag-based material, a resistor layer, and a terminal electrode at one time can simplify the manufacturing process and reduce costs. it can.

(7) The thickness variation of the resistor layer 22 is reduced by adopting an ink jet direct drawing method in which resistive ink is transferred using a piezoelectric actuator element.
The resistance value can be suppressed to about 1%, and the resistance value adjustment step is not required depending on the product type.

(8) Since the green sheet is cut into individual products and then fired, the final product shape is stabilized, and as a result, product mounting reliability in the board assembly process can be improved.
In addition, since the processing of the terminal electrodes is performed in the state of a multi-piece wafer, the production efficiency can be further improved.

FIGS. 6 and 7 show another embodiment of the present invention. In this case, the manufacturing process is as shown in FIG. 2, but the front terminal electrode printing, the drying process # 7, the back terminal electrode printing,
Conductive paste 32 (terminal electrode 4) to be printed in drying step # 8
Are different from each other. That is, in FIG. 6, in the cutting step # 10,
The conductor paste 32 is printed discontinuously so as not to cross the cutting line D when cutting. Therefore, the cutting process #
At 10, cutting is performed along the cutting lines C and D to separate the laminated chip into individual products.
As shown in FIG. 7, the square plate type chip resistor obtained by sequentially performing the plating step # 12 has the terminal electrode 4 that is narrower than the width W1 of the cover 10 and reaches both side surfaces 10a of the cover 10. It is possible to adopt a configuration having a lateral width W2 that does not.

The same or corresponding parts as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the embodiment shown in FIGS. 6 and 7, since the terminal electrode 4 is narrower than the lateral width of the cover 10 and does not reach the side surface of the cover, the terminal electrode 4 when mounted on substrates of various devices is used. The solder fillet generated in the portion does not protrude beyond the outer shape width of the product, so that even higher density mounting is possible.

In each of the above-described embodiments, the resistor film is formed on the base material in a predetermined pattern by the ink jet direct drawing method. It is also possible to employ. Further, a solid film or a thin plate-like resistor whose resistance value is set with high precision in advance may be attached to a ceramic green sheet as a base material.

Further, by changing only the cutting position of the block-shaped laminated body in the cutting step (for example, separating as a laminated body chip including a plurality of resistor layers), development into a chip resistor array product is also possible. is there.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and various modifications and changes can be made within the scope of the claims. There will be.

[0050]

As described above, according to the present invention,
It is possible to obtain a square-plate type chip resistor that does not require front and back sorting, is compatible with high-density mounting, and can be produced at low cost.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a square chip resistor according to the present invention.

FIG. 2 is a manufacturing process diagram showing an embodiment of a method for manufacturing a square chip resistor according to the present invention.

FIG. 3 is a perspective view for explaining a sheet forming step # 1 to a resistor forming step # 3.

FIG. 4 is a perspective view for explaining an upper layer sheet material laminating step # 4 to a terminal electrode hole forming step # 6.

FIG. 5: Front terminal electrode printing, drying step # 7 to cutting step #
It is a perspective view for explaining 10.

FIG. 6 is a perspective view for explaining a front terminal electrode printing and drying step # 7 to a cutting step # 10 according to another embodiment of the present invention.

FIG. 7 is a perspective view showing a square plate type chip resistor in a completed state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Square-plate type chip resistor 2 Internal electrode 3 Resistor 4 Terminal electrode 5 Concave groove 10 Coating body 20 Base material 21, 32 Conductive paste 22 Resistor layer 23 Upper layer sheet material 30 Laminated body 31 Terminal electrode hole

Claims (4)

[Claims] 1. A film- or thin-film resistor is provided between internal electrodes, a ceramic coating is provided to cover the front and back surfaces of the internal electrode and the resistor, and both ends of the coating are connected to the internal electrodes. A square plate type chip resistor provided with terminal electrodes. 2. The groove according to claim 1, wherein a concave groove penetrating in the front and back direction is formed on both end surfaces of the cover, and an exposed portion of the internal electrode is connected to the terminal electrode on an inner surface of the concave groove. Square plate type chip resistor. 3. A step of providing a first conductor paste serving as an internal electrode on a first unfired ceramic sheet serving as a cover, and providing a film or a thin plate-like resistor between the first conductor pastes. The second unsintered ceramic sheet as the body is
Laminating on the unsintered ceramic sheet to form an unsintered ceramic sheet laminate sandwiching the first conductor paste and the resistor between the first and second unsintered ceramic sheets; Forming a through hole or a groove penetrating the laminate at a position penetrating the conductive paste, and forming a terminal electrode on the front and back surfaces of the laminate and the inner surface of the through hole or the groove;
Providing a conductive paste of the above, and after cutting the laminate so as to include at least one of the resistors and the first conductor paste on both sides of the at least one resistor, and separating into a laminate chip, And baking the laminated chip. 4. The square plate type chip resistor according to claim 3, wherein a resistive ink serving as said resistor is attached between said first conductive paste on said first unfired ceramic sheet by an ink jet method. Production method.