JP4384787B2 - Chip resistor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a chip resistor in which a resistor film is provided on a chip-type insulating substrate. More specifically, the present invention relates to a chip resistor that has a simple manufacturing process and can be manufactured at a low cost, while obtaining high-performance characteristics.
[0002]
[Prior art]
Conventional chip resistors include thick film resistors that form electrodes and resistors by printing and baking, and thin film resistors that produce electrodes and resistors by sputtering and the like. Although there is a difference between a thick film and a thin film, both are almost the same structure, for example, as shown in FIG. That is, in FIG. 4, a pair of electrodes 2 and 3 are formed by upper surface electrodes 21 and 31 and rear surface electrodes 22 and 32 and side electrodes 23 and 33 connecting them to opposite ends of the insulating substrate 1 made of alumina or the like. The resistor 4 is formed on the insulating substrate 1 so as to be connected to both electrodes. And the protective film 5 is formed in 1-3 layers on the surface side of the resistor. The thick film is formed with a thickness of about 5 to 10 μm, for example, and the thin film is formed with a thickness of about 0.1 to 0.5 μm, for example.
[0003]
Thick film resistors are applied by printing a paste or other material made of glass or resin, and fired at about 600 to 1000 ° C. (for glass) or cured at about 200 to 240 ° C. (for resin). Is obtained. As the electrode material, Ag-based (silver-based) in which Pd is added to Ag, Au, Ni, Cu, or the like) metal paste is used, and as the resistor material, a resistance value required for ruthenium oxide (RuO ₂ ). For example, a paste made of glass or resin mixed with Ag or Pd is used. The thin film resistor is obtained by forming a metal material by sputtering and patterning, and Al, Cu, Ni, etc. are used as the electrode material, and Ni—Cr alloy etc. are used as the resistance material. Used.
[0004]
In this way, the manufacturing process differs in that one is provided by printing and heat treatment, while the other is provided by sputtering or the like, and also in terms of equipment such as a printing apparatus and a sputtering apparatus, and the production line is completely different. ing. Therefore, using both films together makes the manufacturing process complicated and practically difficult. In addition, when a thick film is formed on the thin film, the adhesion force decreases, the contact resistance increases, and the resistance value does not become constant. Therefore, at least the resistor is formed as a thin film, and the side electrode connected thereto is formed as a thick film. There is no example formed with.
[0005]
[Problems to be solved by the invention]
As described above, there are a thick film resistor and a thin film resistor in the chip resistor. The thick film resistor has a very low manufacturing equipment, and the resistor itself can be manufactured at a low cost. However, the thick film resistor is a paste made of ruthenium oxide with glass powder or the like, and the addition of Ag, Pd, etc. for adjusting the uniformity of the composition, the uniformity of the thickness when applied, and the resistance value adjustment. There is a problem that the accuracy of the resistance value obtained due to the difference in the amount is inferior, and the performance is inferior such that the noise characteristic is poor due to the mixing of the glass material. Thin film resistors are excellent in resistance accuracy and noise characteristics, but sputtering devices must be used, and it takes time to form each film, which is quite expensive. There is a problem.
[0006]
On the other hand, when a thick film and a thin film are mixed, there is no problem of adhesion when a thin film is formed on the thick film, in addition to the complexity of the production line as described above. When the film is formed, there is a problem that the adhesion is lowered, the contact resistance is increased, and the quality is not constant.
[0007]
The present invention has been made in view of such a situation, and provides a chip resistor capable of improving the accuracy of the resistance value and improving the productivity while improving the resistance characteristics such as noise characteristics. For the purpose.
[0008]
[Means for Solving the Problems]
The present inventor forms a resistor having a great influence on the resistance characteristics as a thin film, and all other electrodes and protective films are formed in a thick film, thereby greatly increasing the manufacturing man-hour while maintaining the resistance characteristics at a high performance. As a result of intensive investigations to obtain a low-cost and high-performance chip resistor, even when a thick film electrode is formed on a thin film resistor, a thick film electrode of silver glass paste or silver By selecting a material such as a thick film electrode made of resin paste, the side electrode is provided with good adhesion, and the side electrode is formed so as to be in contact with the thick film electrode. It has been found that can be formed. Here, the metal-based glass paste means a paste in which a metal glass component such as Au, Ni, or Cu is a binder, and the silver-based resin paste means a paste in which a resin containing silver as a main component is a binder.
[0009]
Chip resistor according to the present invention, an insulating substrate, a resistor thin film across the surface of the insulating substrate is provided so as to extend at both ends direction opposite of said insulating substrate, both ends of the resistive element antibodies A pair of thick film top electrodes provided on the surface of the part, a pair of thick film back electrodes provided on the back surface of the insulating substrate corresponding to the top electrode, and side surfaces of the both ends of the insulating substrate provided, the side electrodes of the pair of thick film connected the upper electrode and a back electrode respectively electrically, Ri Do and a protective film provided on the resistor surface sandwiched between the pair of upper surface electrode The upper surface electrode is formed by firing a metallic glass paste .
[0010]
Here, the thick film means a film formed thickly by applying the electrode or resistor material in the form of a paste and firing or curing. The thin film directly forms a metal film by sputtering or the like. This means a thin film formed.
[0011]
With this configuration, the resistor is formed of a thin film, so it is formed with a uniform thickness with a very uniform component, the resistance value is constant and accurate, and the temperature coefficient is also unique to the metal. A constant temperature coefficient can be obtained, and since a glass component or the like is not included, the noise characteristic is good and the resistor has excellent electric characteristics. On the other hand, when the upper surface electrode is formed on the thin film resistor with a thick film, if the material is selected, the thin film resistor is formed with good adhesion and the side electrode formed in contact with the upper surface electrode is also thick. The films are formed with good adhesion to the top electrode. As a result, even if the electrode material is entirely formed of a thick film, it can be formed without causing contact resistance, and most of the manufacturing process can be formed by a simple thick film process.
[0012]
By the upper surface auxiliary electrode formed by a silver-based resin paste between a connection portion of the front SL upper surface electrode and the side electrodes are provided to improve resistance to solder eliminates be melted solder reliability Will improve.
[0013]
If the upper surface electrode is formed by curing a silver-based resin paste, good adhesion to the thin film resistor can be obtained, and it is not necessary to fire at a high temperature. High performance chip resistance can be obtained in a simple manufacturing process.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, the chip resistor of the present invention will be described with reference to the drawings. The chip resistor according to the present invention is shown in FIG. 1 in a cross-sectional explanatory view of one embodiment thereof, on the insulating substrate 1 having a rectangular planar shape made of, for example, alumina, etc. A thin film resistor 4 is formed so as to extend in the direction. A pair of thick film upper surface electrodes 21, 31 are provided on the surface of both ends of the resistor 4, and a pair of thick film rear surface electrodes 22, 32 are provided on the back surface of the insulating substrate 1 corresponding to the upper surface electrodes 21, 31. And a pair of thick-film side electrodes 23 and 33 for electrically connecting the upper surface electrodes 21 and 31 and the rear surface electrodes 22 and 32 respectively are provided on the side surfaces of the both end portions of the insulating substrate 1. A pair of electrodes 2 and 3 are formed. A protective film 5 is provided on the surface of the resistor 4 sandwiched between the pair of upper surface electrodes 21 and 31.
[0015]
In other words, in the chip resistor according to the present invention, only the resistor 4 that greatly affects the resistance characteristics such as accuracy and resistance characteristics such as noise is formed by a thin film, and the other upper surface electrodes 21 and 31 and lower surface electrodes 22 and 32, It is characterized in that the manufacturing process is simplified by forming the side electrodes 23, 33 and the like with a thick film. That is, as described above, in general, when a thick film is formed on a thin film, there is a problem that the adhesiveness is lowered and contact resistance is likely to occur. It has been found that by selecting the material of the thick film electrode provided on the resistor 4, the thick film upper surface electrodes 21 and 31 can be laminated without causing the problem. Then, by forming the side electrodes 23 and 33 with a thick film so as to be connected to the thick film, the thick films can be connected with good adhesion, and a thick film side electrode is formed on the thin film resistor. I found that I can do it.
[0016]
As the substrate 1, for example, alumina, sapphire, Si wafer or the like is used. As a thick film electrode material, a paste obtained by mixing metal powder and glass or resin is generally used. Depending on the mixed metal powder, Ag-based, Ag-Pd-based, Au-based, etc. are used. However, in the example shown in FIG. 1, thick film electrodes made of Au-based, Ni-based, or Cu-based glass paste are used as the upper surface electrodes 21, 31. Here, “system” means that other elements can be added while these are the main components. The glass paste is cured by firing at about 600 to 1000 ° C., and the resin paste is cured by raising the temperature to about 200 to 240 ° C.
[0017]
In the example shown in FIG. 1, upper surface auxiliary electrodes 24 and 34 made of an Ag-based resin paste are formed on the upper surface electrodes 21 and 31. Then, side electrodes 23 and 33 are formed of thick film electrodes made of Ag-based resin paste on the side surfaces of the insulating substrate 1 so as to connect the upper surface auxiliary electrodes 24 and 34 and the back surface electrodes 22 and 32. The auxiliary electrodes 24 and 34 are provided in order to prevent the Au of the upper surface electrodes 21 and 31 from being easily melted into the solder, so that they are not eroded during soldering. The back electrodes 22 and 32 are formed of a thick film made of Ag-based glaze paste (glass paste) or Au-based metal organic material (glass paste). A pair of electrodes 2 and 3 are formed by providing Ni plating layers 25a and 35a and solder plating layers 25b and 35b on the surface of the electrodes.
[0018]
For the resistor 4, for example, a metal film of Ni—Cr, Ta, Ta—N, Ta—Si, or the like can be selected and used according to a desired resistance value. Note that “system” means that the resistance value can be adjusted by adding other elements such as Al, Cr, and O. The resistor 4 is formed as a thin film by forming a film by sputtering or the like and patterning it into a desired shape by a photolithography process.
[0019]
In the example shown in FIG. 1, the protective film 5 has an example of a two-layer structure of the first protective film 51 and the second protective film 52, but two layers are not necessarily required, and one layer or three layers But you can. The first protective film 51 is, for example, a thin film formed of Al ₂ O ₃ , SiO ₂ , SiN or the like, or a glass powder such as lead borosilicate glass applied as a paste and applied by printing or the like. It is formed by baking at about ° C. In order to adjust the resistance value of the resistor 4, the first protective film 51 includes a step of adjusting a resistance value of the resistor 4 by cutting a part of the resistor 4 by laser trimming while measuring the resistance value of the resistor 4. It is provided for the purpose of preventing the resistor material that has been shaved off from being scattered and adhering to the resistor 4 again and changing its performance. Absent.
[0020]
The second protective film 52 protects the exposed surface of the resistor 4 by applying it onto the first protective film 51 that is laser-trimmed and has a concavo-convex surface. A second protective film may be formed in a two-layer structure by separately providing a protective film. Since the resistance value of the resistor 4 may change when the second protective film 52 is baked at a high temperature, it is preferable to apply a resin paste made of an epoxy resin or the like and cure it at about 200 to 240 ° C. .
[0021]
Next, a method for manufacturing this chip resistor will be described with reference to the flowchart shown in FIG. FIG. 1 shows a cross-sectional explanatory view of one chip resistor. However, when actually manufactured, a large substrate of about 5 to 10 cm × 5 to 10 cm has a size of about 100 to 10,000. The electrodes and resistors are simultaneously formed, side electrodes are formed on the exposed side surfaces by cutting into a bar shape, and then the chip resistors connected in a bar shape are cut and separated into individual pieces. .
[0022]
First, an Ag-based glaze paste or an electrode material paste made of an Au-based metal organic material is printed at a predetermined location on the back surface of the substrate 1. Then, thick film back electrodes 22 and 32 (see FIG. 1) are formed by baking at about 600 to 1000 ° C. (S1). Next, a Ni—Cr-based or Ta-based resistive material is formed on the entire surface of the substrate 1 by sputtering, and is patterned into a predetermined shape that extends in a direction connecting both ends of the substrate using a photolithography process. Thus, the resistor 4 is formed (S2). Next, an electrode material made of Au-based, Ni-based, or Cu-based glass paste is applied to the surface of both ends (portions corresponding to the back electrodes 22, 32) of the resistor 4 by printing, and then fired. Electrodes 21 and 31 are formed (S3).
[0023]
Then, the 1st protective film 51 is formed by apply | coating and baking glass paste, such as lead borosilicate glass, on the surface of the resistor 4 by printing etc. (S4). This step may be omitted. Then, while the probe electrode is brought into contact with the pair of upper surface electrodes 21 and 31 and the resistance value is measured, laser trimming is performed so as to obtain a desired resistance value, and the resistance value is adjusted (S5). Further, a second protective film 52 is formed by applying and curing a resin paste on the surface (S6). Next, for example, an electrode material made of Ag-based organic paste (resin paste) in which Ag and Pd are mixed with a resin is applied onto the upper surface electrodes 21 and 31 by printing and cured at about 200 ° C. 24 and 34 are formed (S7).
[0024]
Next, the large substrate is cut into a bar shape so as to be separated into rows arranged in a direction perpendicular to the direction connecting the pair of upper surface electrodes 21 and 31 (S8). Then, an electrode material made of an Ag-based resin paste is applied and cured between the upper surface auxiliary electrodes 24 and 34 and the back surface electrodes 22 and 32 so as to overlap the upper surface auxiliary electrodes 24 and 34 and the back surface electrodes 22 and 32. Thus, the side electrodes 23 and 33 are formed (S9). Thereafter, the chip resistors connected in a bar shape are divided into individual chips (S10), and Ni plating layers 25a, 35a and solder plating layers 25b, 35b made of Pb / Sn etc. are formed on the exposed surfaces of the electrodes. (S11), the chip resistor shown in FIG. 1 is obtained.
[0025]
According to the present invention, since only the resistor is formed of a thin film and all the electrodes including the side electrodes are formed of a thick film, the number of steps in the manufacturing process does not increase so much and can be obtained at low cost. In addition, the resistor that easily affects the resistance characteristics is formed of a thin film by sputtering a metal material. Therefore, the metal thin film is formed of a uniform material and a uniform thickness, and a very high-precision resistor. Is obtained. In addition, when the upper surface electrode is provided on the lower side of the resistor, it is difficult to confirm the contact location of the monitoring probe for measuring the resistance value in the laser trimming process, but the upper surface electrode is provided on the surface side of the resistor. Therefore, there is also an advantage that the confirmation of the electrode becomes easy.
[0026]
At this time, generally, when a thick film electrode such as a side electrode is formed on a thin film resistor, adhesion between the two is not completely obtained, and contact resistance is likely to occur. Since the metal paste is used for the upper surface electrode, the thin film resistor and the upper surface electrode are in excellent contact with each other. On the other hand, the side electrodes are structured to be connected to the thick film upper surface electrode or the thick film upper surface auxiliary electrode provided thereon. Provided. As a result, the thin film resistor and the thick side electrode can be connected with a very small contact resistance.
[0027]
FIG. 2 is a cross-sectional explanatory view showing another embodiment of the chip resistor according to the present invention. In the above example, the upper surface electrodes 21 and 31 are formed by printing and baking Au-based, Ni-based or Cu-based glass paste. In the example shown in FIG. 2, the upper surface electrodes 21 and 31 are formed of silver (Ag). It is characterized by the fact that it is formed of a resin paste. As a result of the study of the present inventors, it was confirmed that even if such a silver-based resin paste was used, sufficient adhesion of the thin film resistor 4 was obtained. In this example, since the upper surface electrodes 21 and 31 are made of a solder-resistant Ag-based material, it is not necessary to provide an auxiliary electrode thereon. The other structure is the same as the example shown in FIG. 1, and the same parts as those in FIG. Also, the manufacturing process is the same as that shown in FIG. 2, except that the material of the upper surface electrode is different, the curing temperature is different, and the upper surface auxiliary electrode is not provided.
[0028]
By using such an Ag-based resin paste as the upper surface electrode, the curing temperature can be reduced at a low temperature of about 200 ° C., so there is no concern about oxidation of the resistor, and no countermeasure is required.
[0029]
【The invention's effect】
According to the present invention, the resistor that has a great influence on the resistance characteristics is formed by a thin film, so that the electrodes such as other side electrodes are all formed by a thick film while being a high-performance resistor. The manufacturing process is very simple and can be manufactured at a very low cost with fewer man-hours. In addition, the problem of adhesion between the side electrode formed by the thick film and the thin film resistor is also solved, and there is almost no deterioration in the characteristics as compared with the case where all are formed by the thin film, and the film can be obtained at a very low cost.
[Brief description of the drawings]
FIG. 1 is a cross-sectional explanatory view showing an embodiment of a chip resistor according to the present invention.
FIG. 2 is a cross-sectional explanatory view showing a modification of the chip resistor of FIG. 1;
FIG. 3 is a flowchart of an example for manufacturing the chip resistor of FIG. 1;
FIG. 4 is a cross-sectional explanatory view illustrating the structure of a conventional chip resistor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Board | substrate 2, 3 Electrode 4 Resistor 5 Protective film 21, 31 Upper surface electrode 22, 32 Back surface electrode 23, 33 Side surface electrode 24, 34 Upper surface auxiliary electrode

Claims (3)

An insulating substrate, a resistor thin film across the surface of the insulating substrate is provided so as to extend at both ends direction opposite of the insulating substrate, a pair which is provided at both ends surfaces of the resistive element antibodies thickness A top electrode of the film, a pair of thick film back electrodes provided in a portion corresponding to the top electrode on the back surface of the insulating substrate, and provided on side surfaces of the both ends of the insulating substrate; and the side electrode of the pair of thick film for connecting the back electrode, respectively electrically, wherein Ri Do and a protective film provided on the resistor surface to be sandwiched between a pair of upper surface electrode, the upper electrode is metallic glasses chip resistor ing formed by firing a paste. Chip resistor according to claim 1, wherein the upper surface auxiliary electrode of the thick film formed by the silver-based resin paste is provided between the connection portion of the upper surface electrode and the side surface electrode. An insulating substrate, a thin film resistor that is provided entirely on the surface of the insulating substrate so as to extend in the direction of opposite ends of the insulating substrate, and a pair of thicknesses provided on the surfaces of both ends of the resistor A top electrode of the film, a pair of thick film back electrodes provided in a portion corresponding to the top electrode on the back surface of the insulating substrate, and provided on side surfaces of the both ends of the insulating substrate; A pair of thick side electrodes that electrically connect the back electrodes, respectively, and a protective film provided on the resistor surface sandwiched between the pair of top electrodes, the top electrode being a silver-based resin paste Ruchi-up resistor, such is formed by curing the.

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