JP3435419B2 - Chip resistor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip resistor. 2. Description of the Related Art Conventionally, the electrode structure of a chip resistor is formed by applying and baking a so-called metal glaze paste containing Ag—Pt or the like using glass as a binder. In the conventional chip resistor, Japanese Patent Publication No. 58-4
As disclosed in Japanese Patent No. 6161, a metal glaze electrode is made of Ag in which Ag is mixed in a thermosetting resin.
-There is one in which an electrode is formed by encapsulating with a resin-based conductive paste and curing by heating. In the conventional chip resistor structure, there is a problem that the scribing is liable to fail and the scribed end face is missing, resulting in poor yield.
There is also a problem that the conductive paste is cut or thinned at the corners of the substrate. An object of the present invention is to provide a method of manufacturing a chip resistor that can solve the above problems. [0006] Means for Solving the Problems] chip resistor of the present invention includes a base plate, a pair of first electrodes formed using a metal glaze paste on both ends of the surface of the substrate, the back surface of the substrate A pair of second electrodes formed using a metal glaze paste so as to face the first electrode, a resistor printed between the pair of first electrodes, and a glass cover covering the surface of the resistor
Protective coat consisting of a coat, resistor and protective coat
The trimming groove formed and filled with the trimming groove
Resin coat formed to have a flat surface
If, so as to extend over the first electrode and the second electrode on the end face of the substrate
A third electrode made form, the first electrode composed of a plating layer formed on the second electrode and the third electrode. As in the present invention, in a substrate obtained by scribing a ceramic substrate having slits formed on both sides, it is difficult for defects such as chips to enter the scribed end surface. In particular, in the present invention, a resistor and a protective coat are used.
Fills the trimming groove formed over and flat surface
Since the resin coat is formed to be, chip resistance
The suction nozzle for placing the device on the circuit board for mounting is a flat register.
Adsorbs firmly on the coat. When the third electrode is formed of a resin-based conductive paste, the conductive paste for forming the third electrode is cut or thinned even if the third electrode is formed on the end surface formed by scribing. There is nothing. Even if the third electrode is formed of a resin-based conductive paste, the first electrode and the second electrode
Since the electrode is formed using a heat-resistant metal glaze paste and a plating layer is formed on the first to third electrodes, the plating layer serves as a buffer layer and the third electrode is formed by the heat of the solder. It can prevent peeling. In addition, since the first electrode and the second electrode that are resistant to heat exist, even if the third electrode is formed using a resin-based conductive paste, it is possible to prevent the soldering strength from being lowered. The manufacturing method of the chip resistor of the present invention
Of a ceramic plate with a plurality of slits facing
A plurality of first electrodes using metal glaze paste on the surface
Forming the first electrode on the back surface of the ceramic plate
Use multiple metal glaze pastes to
Forming two electrodes and a predetermined one of the plurality of first electrodes
A plurality of resistors are respectively formed between the pair of first electrodes.
Process and protective coating made of glass coat on the surface of the resistor
And the ceramic plate along the slit
The process of scribing and dividing into multiple substrates and the edge of the substrate
A third electrode on the surface so as to straddle the first electrode and the second electrode
By the process of forming and by laser or sand blasting,
Process for forming trimming grooves in resistor and protective coating
And fill the trimming groove and make the surface flat
Forming a resin coat on the surface of the protective coat; and
Forming a plating layer on the three electrodes. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a chip resistor 1 of this embodiment has a convex resistor 3 formed on the surface of a ceramic substrate 2.
Are printed and electrodes 4 are provided at both ends thereof.
Resistor 3 is provided in the thickness of the ruthenium oxide to about 10 [mu] m,
Trimming grooves 5 are formed upward from the bottom of the convex shape by laser or sand blasting, and resistance values are trimmed. The electrode 4 of the chip resistor 1 is connected to the resistor 3
Has a first electrode 6 directly connected, and a second electrode 7 formed so as to oppose the first electrode 6 and the substrate 2,
The first and second electrodes 6 and 7 are Ag-Pd, Ag-Pt.
A metal glaze paste such as is formed by printing. Further, a third electrode 8 made of an Ag-resin-based conductive paste in which Ag is mixed with xylene or epoxy phenol resin is provided on the end face of the substrate across the first and second electrodes 6 and 7. The electrode 8 includes first and second electrodes 6,
7 is provided so as to cover a part thereof, and the two are made conductive. Then, Ni plating 9 and solder plating 10 are applied to cover the entire first, second and third electrodes. The surface of the resistor 3 is protected by applying a glass coat 11 and a resin coat 12. As shown in FIGS. 3A to 3F, the chip resistor is manufactured by first manufacturing a ceramic plate 1 serving as a substrate.
A plurality of rows of metal glaze paste to be the first electrodes 6 are printed at predetermined intervals across the three slits 14 and fired at a temperature close to 900 ° C. Similarly, the second electrode 7 is also the first electrode.
It is formed at a position facing the electrode 6. Next, as shown in FIG. 3B, the resistor 3 is printed and formed in a matrix on the ceramic plate 13 between the first electrodes 6 and fired at an average temperature of 850 ° C. And as shown to FIG. 3C, the glass coat 11 is given to the surface of the resistor 3, and it bakes at the temperature of an average of 650 degreeC. Thereafter, the ceramic plate 13 is cut (scribed) along the slits 14 provided vertically and horizontally for each chip resistor, and as shown in FIG.
The third electrode 8 of the resin-based conductive paste was coated to a thickness of about 20 [mu] m, and cured at a temperature of about 200 ° C.. Then, as shown in FIGS. 3E and 3F, Ni plating 9 and solder plating 10 are sequentially applied to each of the first, second, third electrodes 6,
7 and 8 are coated. In this case, since the slits 14 are provided from both sides of the substrate, when the resin is applied in a state of being partially overlapped with the end surface of the ceramic substrate, a good state both electrically and mechanically can be obtained. According to this method, the terminal electrode is not peeled off or has a defect such as slack on the end face of the ceramic substrate. As shown in FIG. 1, the terminal electrode can also be formed on the side end portion 5 surface. The resistor 3 of each chip resistor is trimmed to adjust the resistance value, and a resin coat 12 such as an epoxy resin is used.
And cured at a temperature around 200 ° C. In FIG. 3, it is shown that the trimming is performed after the plating process.
In the method of the present invention, the trimming is performed in the state shown in FIG. 3C before the plating process is performed. Then, a resin coat 12 is applied as a protective coat on the glass coat 11 and the steps shown in FIG. Accordingly, the trimming operation can be performed efficiently because the resistance value is trimmed without separating the ceramic plate 13 for each chip. In addition, since the trimming groove is covered with the resin coat 12, the resistor is not adversely affected during the subsequent plating operation. According to the chip resistor of this embodiment, the resistance of the electrode 4 is improved with respect to the solder bite, and the circuit board can be bent only by the metal glaze system and more flexible than the electrode. Strong because of its high nature. In addition, since the first and second electrodes 6 and 7 are firmly soldered to the circuit board, the fixing force to the circuit board during soldering is extremely strong,
A decrease in fixing force due to the third electrode made of an Ag-resin system does not occur. The resistor of the chip resistor of the present invention can be appropriately selected according to its use, such as a metal film resistor or a carbon film resistor. Further, the components of the metal glaze paste and the Ag-resin conductive paste may contain other additives as appropriate. This chip resistor is provided with an Ag-resin third electrode on the end face of the substrate across the metal glaze first and second electrodes provided on both surfaces of the substrate. Since the Ni plating layer covering the third electrode and the solder plating layer covering the Ni plating layer are formed, it is strong against soldering and can be reattached to the circuit board. Since the third electrode is provided so as to partially overlap the second electrode on the lower surface side of the substrate,
A step is formed by the electrode on the lower surface side of the substrate, and when soldering to the circuit board, the solder turns into a gap generated between the lower surface side electrode and the circuit board, and a strong fixing force is obtained. In addition, since the Ag-resin-based third electrode provided on the end face of the substrate has appropriate flexibility, it can sufficiently withstand the bending of the circuit substrate. In the above-described chip resistor manufacturing method, a resin-containing silver paint is directly applied to the end surface on the substrate side after scribing in a state of being partially overlapped on the first and second electrodes on the front and back surfaces at a low temperature. Since the third electrode is formed by heat treatment, the third electrode is directly bonded to the rough cut section of the substrate, and the third electrode has a strong adhesive force. In addition, when the soldering electrode is plated, the third electrode can effectively prevent the plating solution from penetrating, and a high-quality product that does not cause defects such as peeling or cracking on the electrode can be manufactured. Also, if the resin coat is applied before plating, the resistor weak against the plating solution is protected by the resin coat.
The characteristics of the resistor can also be maintained. Therefore, chip resistors are also downsized due to today's demands for higher packaging density, but sufficient fixing force can be obtained even if the electrodes are small, and the size and weight of electrical products are reduced, reliability and durability. And greatly contribute to the improvement of productivity. If a protective coat is applied on the glass coat before the plating treatment as in the present invention, the plating solution does not enter the trimming groove, the characteristics of the resistor change, There is an advantage that the peeling of the body can be prevented. When a resin coat is used as a protective coat, the firing temperature of the resin coat is considerably lower than that of the glass coat, so that the electrical characteristics of the resistor trimmed by heat when forming the resin coat are substantially changed. There is an advantage of not. According to the present invention, a resistor and a glass coat are used.
The trimming groove formed over the protective coat
Form a resin coat that fills and flattens the surface
So the chip resistor is placed on the circuit board for mounting
The nozzle firmly adheres to the flat resin coat.
In addition, when the third electrode is formed using a resin-based conductive paste, there is an advantage that the conductive paste is not further cut or thinned. And even if the third electrode is formed of a resin-based conductive paste,
Since the first electrode and the second electrode are formed by using a heat-resistant metal glaze paste, and the plating layer is formed on the first to third electrodes, the plating layer serves as a buffer layer and the solder layer The third electrode can be prevented from peeling off due to heat. In addition, since the first electrode and the second electrode that are resistant to heat exist, even if the third electrode is formed using a resin-based conductive paste, it is possible to prevent the soldering strength from being lowered. As in the method of the present invention, there are slits on both sides.
A substrate obtained by scribing the formed ceramic substrate
If used, defects such as chips will enter the scribed end face.
Difficult, and as a result, on the end face formed by scribe
Even if three electrodes are formed, the conductivity for forming the third electrode
The paste does not break or thin.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an embodiment of a chip resistor according to the present invention. FIG. 2 is a cross-sectional view taken along the line AA of FIG. FIG. 3 (A), (B), (C), (D), (E),
(F) is a longitudinal cross-sectional view which shows the manufacturing process of an example of the chip resistor of this invention. [Description of Symbols] 1 Chip resistor 2 Substrate 3 Resistor 4 Electrode 5 Trimming groove 6 First electrode 7 Second electrode 8 Third electrode 9 Ni plating 10 Solder plating 11 Glass coat 12 Resin coat 13 Ceramic plate 14 Slit

   ──────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Mitsuru Yokoyama               3158 Okubo, Osawano-machi, Kamishinkawa-gun, Toyama               Within Hokuriku Electric Industry Co., Ltd. (72) Inventor Yozo Ohara               3158 Okubo, Osawano-machi, Kamishinkawa-gun, Toyama               Within Hokuriku Electric Industry Co., Ltd.                (56) References JP-A-60-27104 (JP, A)                 JP 58-101 (JP, A)                 JP 61-268001 (JP, A)                 JP 57-184202 (JP, A)                 JP 55-99701 (JP, A)                 Shokai 61-186209 (JP, U)                 Shokai Sho 62-78705 (JP, U)

Claims (1)

(57) [Claims] A base plate, a pair of first electrodes formed using a metal glaze paste on both ends of the surface of the substrate, which is formed by using a metal glaze paste so as to face the first electrode on the back surface of the substrate A pair of second electrodes; a resistor printed between the pair of first electrodes; a protective coat made of a glass coat covering the surface of the resistor; and the resistor and the protective coat. Tori
Filling the trimming groove and the trimming groove and making the surface flat
A resin coating which is formed, and a third electrode made form to extend over the first electrode and the second electrode on the end face of the substrate, the first electrode, the second electrode and the third electrode A chip resistor comprising a plating layer formed on the top. 2. The resistor is formed using ruthenium oxide and
One about has 10μm thickness, the third electrode using a conductive paste of resin-based shape
The chip resistor according to claim 1 formed. 3. Ceramic with multiple slits facing both sides
Using metal glaze paste on the surface of the back plate
Forming a first electrode and facing the first electrode on the back surface of the ceramic plate;
Form multiple second electrodes using metal glaze paste
And a predetermined pair of first electrodes among the plurality of first electrodes.
A step of forming each of the plurality of resistors, and a protective coat made of a glass coat on the surface of the resistor
And scribe the ceramic plate along the slit.
A step you divided into a plurality of substrates Te, to the first electrode and the second electrode on the end face of the substrate
The step of forming the third electrode so as to straddle, and the resistor and the front by laser or sand blasting
Forming a trimming groove in the protective coating, and filling the trimming groove and flattening the surface
Forming a resin coat on the surface of the protective coat;
And a step of forming a plating layer on the third electrode.
A method of manufacturing a resistor.