JP3826046B2 - Resistor and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resistor such as a chip resistor having a low resistance value and a low resistance temperature coefficient, and more particularly to its structure and its manufacturing method.
[0002]
[Prior art]
In recent years, demand for small electronic devices such as mobile phones and notebook computers has been increasing, and there is a growing demand for higher functionality, higher performance, and smaller size for electronic components used in these electronic devices. . Under such circumstances, chip resistors for surface mounting are widely used. In order to manufacture products that have low resistance temperature coefficients and cover low resistance values among chip resistors, in many cases, the resistivity of the resistor film is relatively high, so the thickness of the resistor film is increased. There is a need to. However, when the thickness of the resistor film is increased, there is a problem in the adhesion between the insulating substrate and the resistor, and there is a problem that the resistor film is easily peeled off.
[0003]
For this reason, it has been attempted to increase the anchoring effect and increase the adhesion with respect to the resistor film disposed on the surface of the insulating substrate by providing many irregularities. As a conventional method for forming irregularities on an insulating substrate, a chemical etching process using chemicals or a physical forming method is known. However, in the conventional method, it cannot be said that the adhesiveness when a low-resistance resistor is formed is sufficient, and cracking or peeling occurs due to stress or strain of the resistor.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described circumstances, and enhances the adhesion between the insulating substrate and the resistor to improve quality and reliability, and also covers a low resistance temperature coefficient and a low resistance value. It is an object of the present invention to provide a resistor that can be used and a method for manufacturing the same.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems, a resistor according to the present invention includes an insulating substrate, a glass layer made of a large number of convex portions formed on the substrate, and a resistor formed on the surface of the glass layer. And at least a pair of front electrodes connected to the resistor, and a protective film covering the resistor.
[0006]
According to the present invention, the adhesion between the insulating substrate and the resistor can be improved. At the same time, the surface area of the resistor can be substantially enlarged, and a substantially wide resistor can be formed. This substantially wide resistor allows the thickness of the resistor to be reduced correspondingly, leading to a reduction in internal stress that causes cracks and avoidance of peeling. In addition, the heat dissipation effect is enhanced and the allowable power of the resistor can be increased. [0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a resistor according to the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is a diagram showing an overall configuration of a chip resistor according to the first embodiment of the present invention. FIG. 1A is a plan view of the chip resistor, and FIG. 1B is a cross-sectional view taken along the line AA.
[0008]
Reference numeral 11 denotes an insulating substrate, which uses a ceramic substrate such as alumina, alumina nitride, or glass alumina. A glass layer 12 composed of a large number of convex portions is formed on the insulating substrate 11. The glass layer 12 is composed of a large number of convex portions having a height of 10 to 100 μm, a width of 10 to 100 μm, and a distance between adjacent patterns of about 10 to 100 μm.
[0009]
An activation layer (not shown) covers the glass layer 12 and is disposed on the insulating substrate 11, and a metal film resistor 15 is disposed on the activation layer. The surface electrodes 13 and 13 are disposed so as to be electrically connected to the metal film resistor 15. The metal film resistor 15 is made of a resistor metal such as Ni—P, Ni—P—Cr, Ni—P—Cu, Ni—P—W, or Ni—P—Fe. In this embodiment, the metal film resistor 15 is formed by electroless plating on the activation layer. Reference numeral 17 denotes a protective film, which is formed of an insulator such as glass or epoxy resin. Reference numeral 23 denotes a plating electrode, which is formed on the front electrode 13, the back electrode 19, and the end face electrode 21.
[0010]
FIG. 2 is a diagram showing an overall configuration of a chip resistor according to the second embodiment of the present invention. The configuration is the same as that of the first embodiment except that a thick film resistor is used as the resistor. It has. That is, a glass layer 12 composed of a large number of convex portions is formed on the insulating substrate 11, and the glass layer 12 has a height of 10 to 100 μm, a width of 10 to 100 μm, and a distance between adjacent patterns of about 10 to 100 μm. It is comprised by many convex-shaped parts. And the thick film resistor 24 is arrange | positioned so that it may bite into the glass layer 12 which consists of this many convex-shaped part. The thick film resistor 24 is made of a sintered material of a resistance metal material such as ruthenium oxide and glass, and is formed by screen printing with a predetermined pattern on the surface of the insulating substrate 11 and firing at a temperature of 800 ° C. to 900 ° C. The Reference numeral 17 denotes a protective film, which is formed of an insulator such as glass or epoxy resin.
[0011]
FIG. 3 is a diagram illustrating a configuration example of a glass layer made up of a number of convex portions. The X direction indicates the short direction of the insulating substrate, and the Y direction indicates the longitudinal direction of the insulating substrate. In FIG. 3A, a glass layer composed of a large number of convex portions is formed continuously along the longitudinal direction of the insulating substrate, and intermittently formed along the short direction of the insulating substrate. It shows that. Hereinafter, it is abbreviated as a convex pattern. As described above, the height is 10 to 100 μm, the width is 10 to 100 μm, the distance from the adjacent pattern is about 10 to 100 μm, and it is formed in a bowl shape.
[0012]
FIG. 3B shows that a glass layer composed of a large number of convex portions is intermittently formed along the longitudinal direction of the insulating substrate and is also intermittently formed along the short direction of the insulating substrate. Indicates that Hereinafter, it is abbreviated as an uneven pattern. Also in this pattern, the height of the convex portion is 10 to 100 μm, the width is 10 to 100 μm, and the distance from the adjacent pattern is about 10 to 100 μm, and is formed in a grid pattern. These convex patterns or concave / convex patterns are formed by, for example, screen printing and baking of glass paste. And it joins with the resistor arrange | positioned at the upper part by favorable adhesiveness.
[0013]
FIG. 4 is a diagram showing comparison data between the chip resistor of the present invention and the conventional one. FIG. 4A is a diagram showing data comparing film formation times for an example of a convex pattern. It can be seen that the film formation time (plating time) for obtaining the same resistance value is shortened. For example, with a plating time of 10 minutes, a resistance value of 5Ω has conventionally been formed, but with the chip resistor of the present invention, a resistance value of about 3Ω can be formed. This is because the surface of the resistor has a convex pattern, so that the surface area of the resistor increases, and in particular, the effective length along the short direction of the insulating substrate of the resistor increases. It is understood that the resistance value decreases with respect to the film thickness.
[0014]
FIG. 4B is a diagram showing data comparing crack / separation occurrence limit resistance values for the concavo-convex pattern. According to this, it can be seen that the limit resistance value at which cracks and peeling occur is reduced. For example, at TCR = 0 PPM / ° C., the conventional limit resistance value (initial resistance value) was 0.23Ω, but the chip resistor of the present invention has a generation limit resistance value (initial resistance value) of 0. It is improved to .15Ω. This has shown that the anchor effect with respect to a resistor is heightened by the uneven | corrugated pattern.
[0015]
Next, a manufacturing method of the chip resistor of the present invention will be described with reference to FIG. This manufacturing method uses a metal film resistor as a resistor. First, as shown in FIG. 5A, an insulating substrate 11 such as alumina is prepared. In the example shown in the figure, one chip region is shown, but in reality, a multi-chip substrate for manufacturing a large number of chip resistors at once is used. A pair of back electrodes 19 and 19 are formed on the back surface of the insulating substrate 11 by screen printing and baking of electrode paste.
[0016]
A glass paste is screen-printed in a predetermined pattern on the surface of the insulating substrate 11 and baked in air at 300 ° C. to 1200 ° C. to form a glass layer 12 having a large number of convex portions. As the predetermined pattern, the convex pattern or the concave / convex pattern shown in FIG. 3 is used, but other patterns may be used.
[0017]
Next, as shown in FIG. 5B, the glass layer 12 is covered, a catalyst paste is applied on the surface of the insulating substrate 11 by screen printing, and baked to form the activated layer 14. Next, as shown in FIG. 5C, a metal film resistor 15 is formed on the activation layer (not shown) by plating. The metal film resistor 15 is made of a resistance metal such as Ni—P, Ni—P—Cr, Ni—P—Cu, Ni—P—W, or Ni—P—Fe, and is formed on the activated layer by electroless plating. It is formed.
[0018]
Next, as shown in FIG. 5 (d), a pair of surface electrodes 13, 13 are formed at the end of the surface of the insulating substrate 11 so as to be electrically connected to the metal film resistor 15. Next, as shown in FIG. 5E, a protective film 17 is formed so as to cover a part of the metal film resistor 15 and the pair of surface electrodes 13 and 13. If necessary, the resistance value is adjusted to a desired value by laser trimming or the like.
[0019]
The above processing is a batch processing of a large number of substrates, and then a process of dividing into strips is performed. Processing may be either dicing or break. After the multi-piece substrate is divided into strips, end face electrodes 21 and 21 are formed on the exposed substrate side end faces as shown in FIG. The end face electrodes 21 and 21 are Ni—Cr thin film layers deposited by sputtering, for example. Then, a process of dividing into single chips is performed. Processing may be either dicing or break.
[0020]
Next, as shown in FIG. 5G, electrolytic plating is performed to form plated electrodes 23 and 23 on the electrodes 13, 19 and 21. In order to prevent electrode cracking and improve solderability, a plating electrode 23 composed of a Ni plating layer and a Sn—Pb plating layer (or Sn plating layer may be used) is formed.
[0021]
FIG. 6 shows a method for manufacturing a chip resistor in which the resistor is a thick film resistor. First, as shown in FIG. 6A, an insulating substrate 11 such as alumina is prepared, and a back electrode 19 is formed. Next, as shown in FIG. 6B, a pair of surface electrodes 13 and 13 are formed on both ends of the surface of the insulating substrate 11. Then, a glass paste is printed on the surface of the insulating substrate 11 according to a predetermined pattern, and fired in air at 300 ° C. to 1200 ° C. to form the glass layer 12 composed of a number of convex portions.
[0022]
Next, as shown in FIG. 6C, the thick film resistor 24 is formed so as to cover the glass layer 12. The thick film resistor 24 is formed over the surface electrode 13 by applying a resistor paste (for example, ruthenium oxide) in a predetermined pattern by screen printing and baking. The thick film resistor 24 is formed so as to be electrically connected to the pair of front electrodes 13 and 13 and to bite into the glass layer 12 composed of a number of convex portions on the surface of the insulating substrate 11.
[0023]
The subsequent steps of FIG. 6D to FIG. 6G are almost the same as those of FIG. 5E to FIG.
[0024]
It goes without saying that the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea. For example, the gist of the present invention can be similarly applied to an integrated circuit element other than a chip resistor.
[0025]
【The invention's effect】
The chip resistor of the present invention forms a glass layer composed of a large number of convex portions on an insulating substrate, and forms a resistor on the glass layer, whereby the resistor is insulated from the insulating substrate by a high anchor effect. Can be fixed to. Thereby, particularly in a chip resistor having a low resistance and a low resistance temperature coefficient, problems such as peeling and cracking are reduced, and the reliability of the chip resistor can be improved. Further, the surface area of the resistor can be substantially enlarged, and a chip resistor having a low resistance and a low resistance temperature coefficient can be efficiently produced. In addition, the heat dissipation effect is enhanced and the allowable power of the chip resistor is increased.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a chip resistor according to a first embodiment of the present invention, (a) is a plan view of the chip resistor, and (b) is taken along line AA. FIG.
FIGS. 2A and 2B are diagrams illustrating an overall configuration of a chip resistor according to a second embodiment of the present invention, wherein FIG. 2A is a plan view of the chip resistor, and FIG. 2B is along a line BB. FIG.
FIG. 3 (a) shows that a large number of glass layers as convex portions are continuously formed along the longitudinal direction of the insulating substrate and intermittently formed along the short direction of the insulating substrate. (B) is a diagram showing that a large number of glass layers that are convex portions are intermittently formed along the longitudinal direction of the insulating substrate, and intermittently even along the short direction of the insulating substrate. It is a figure which shows having been formed.
FIGS. 4A and 4B are diagrams showing comparison data between the chip resistor of the present invention and a conventional one, wherein FIG. 4A is a diagram showing comparison data with respect to film formation time, and FIG. It is a figure which shows the comparison data about generation | occurrence | production limit resistance value.
FIG. 5 is a diagram showing manufacturing steps of the chip resistor according to the first embodiment of the present invention.
FIG. 6 is a diagram illustrating manufacturing steps of the chip resistor according to the second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Insulating board | substrate 12 Glass body 13 which consists of many convex-shaped parts Front electrode 14 Activation layer 15, 24 Resistor 16 Trimming groove 17 Protective film 19 Back electrode 21 End surface electrode 23 Plating electrode

Claims (6)

An insulating substrate, a glass layer composed of a number of convex portions formed on the substrate, a resistor formed on the surface of the glass layer, and at least a pair of front electrodes connected to the resistor; A resistor comprising a protective film covering the resistor. The glass layer composed of the convex portions is formed continuously along the longitudinal direction of the insulating substrate and intermittently formed along the short direction of the insulating substrate. The resistor according to 1. The glass layer made of the convex portion is formed intermittently along the longitudinal direction of the insulating substrate and intermittently formed along the short direction of the insulating substrate. The resistor according to 1. The resistor according to claim 1, wherein the resistor is formed by plating a resistor metal. The resistor according to claim 1, wherein the resistor is a thick film resistor. A method of manufacturing a resistor having an insulating substrate, a surface electrode provided on the insulating substrate, and a resistor connected to the surface electrode,
A method of manufacturing a resistor, comprising: forming a glass layer including a plurality of convex portions on the insulating substrate; and forming a resistor on the glass layer.

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