JPH04258101A - Chip resistor - Google Patents

Abstract

PURPOSE:To enable a suction mistake at the time of automatic packaging due to a recess and a projection on an outermost surface of a chip resistor to be solved and provide for the chip resistor which is superb in packaging property and allows characters to be identified easily in the chip resistor which is used for various kinds of electronic circuits, electrical circuits etc. CONSTITUTION:By changing a sealed character 15 which is formed on a primary coat glass 14 from a conventional thick-film paste to a metal organic paste which is obtained as a thin film by calcination after screen printing, a recess and a projection on an outermost surface of a chip resistor are nearly eliminated and at the same time the chip resistor for enabling characters to be identified easily can be obtained since the sealed characters 15 are thin film.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to chip resistors.

0002

BACKGROUND OF THE INVENTION In recent years, chip resistors have become smaller and lighter and have greatly contributed to higher density electronic circuits.

A conventional chip resistor will be explained below. FIG. 3 shows a cross-sectional view of a conventional chip resistor. In FIG. 3, after forming an Ag-based thick film electrode 32 on an insulating substrate 31 made of alumina or the like, a RuO2-based thick film resistor 33 is formed. Thereafter, after correcting the resistance value using a laser, a primary coat glass 34 is applied to protect the RuO2 thick film resistor 33. Next, a marking paste having a thick film composition is printed and dried on the primary coated glass 34, and then a secondary coated glass for protecting the stamped characters is printed, dried and fired, and the first coated glass 34 and the stamped Characters 35 and secondary coat glass 38 are formed at the same time. After that, the insulating substrate 31 is divided into strips, and Ag
After forming an end face electrode 36 using the thick film electrode 32 of the system, it is divided into individual pieces, and a plating layer 37 is formed on the end face electrode 36.

0004

[Problems to be Solved by the Invention] However, in the above-mentioned conventional chip resistor, since the marking paste is formed from a thick film material, the marking paste 35 causes unevenness on the outermost surface of the chip resistor, which causes problems during automatic mounting. There was a problem in that suction errors occurred.

The present invention is intended to solve the above-mentioned conventional problems, and has very little unevenness on the outermost surface of a chip resistor, and has extremely excellent mounting performance.Since the printed characters are a thin film, the characters can be easily printed. The purpose is to provide excellent chip resistors that are easy to identify.

[0006]

[Means for Solving the Problems] To achieve this object, the chip resistor of the present invention includes an insulating substrate, a pair of electrodes formed on the insulating substrate, and a pair of electrodes connected to the electrodes. The device includes a resistor, a glass film formed on the resistor, and a stamp made of a metal organic substance formed on the glass film.

[0007]

[Function] According to the structure of the present invention, since there are no irregularities on the outermost surface of the chip resistor, suction errors during automatic mounting are greatly reduced, and a chip resistor with excellent mounting performance can be obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A chip resistor according to an embodiment of the present invention will be described below with reference to the drawings. Figure 1(a),(b)
) are diagrams showing a chip resistor in one embodiment of the present invention, and are a top view and a cross-sectional view, respectively. In Figure 1,
11 is an insulating substrate made of alumina, and a pair of thick film electrodes 12 are formed on this insulating substrate 11. Reference numeral 13 denotes a thick film resistor provided so that both ends thereof overlap the thick film electrode 12. A primary coat glass 14 is formed to cover the thick film resistor 13. Stamp characters 15 are provided on this primary coat glass 14. An end surface electrode 16 is provided on the end surface of the insulating substrate 11 so as to be connected to the thick film electrode 12, and a plating layer 17 is further formed to cover this end surface electrode 16.

A method of manufacturing the chip resistor constructed as described above will be explained with reference to FIG. First, an insulating substrate 1 made of 96% alumina with excellent heat resistance and insulation properties.
Accept 1. Next, a conductive paste containing Ag as the main component was screen printed on both ends of the insulating substrate 11, and was heated in a belt-type continuous firing furnace at a temperature of 850°C with a profile of a peak time of 6 minutes and an IN-OUT time of 50 minutes. The thick film electrode 12 is formed by firing.

Next, a thick film resistor paste containing RuO2 as a main component is screen printed so as to be electrically connected to the thick film electrode 12, and fired in a belt type continuous firing furnace under the same conditions as the thick film electrode 12. Then, a thick film resistor 13 is formed. Further, in order to equalize the resistance values of the thick film resistor 13, the resistance values are corrected using a laser beam (oscillation frequency: 5 kHz, output: 3.0 W). After that, the thick film resistor 13
In order to protect the thick film resistor 13, a black overcoat glass paste was screen printed to cover the thick film resistor 13, and a belt-type continuous firing furnace was used to heat the film at a temperature of 600°C for 5 minutes at peak time and 30 minutes at IN-OUT time. The primary coat glass 14 is formed by firing according to the profile. Next, Au
After screen-printing a metal-organic paste containing as a main component onto the primary coat glass 14, it was dried at 120°C for 10 minutes, and then heated in a belt-type continuous firing furnace at a temperature of 600°C for 5 minutes at a peak time and an IN-OUT time of 5 minutes. The stamped characters 15 are formed by baking according to the profile for 30 minutes. Thereafter, this substrate was divided into strips, an end electrode paste containing Ag as a main component was applied to the end surface of the substrate so as to be connected to the thick film electrode 12, and dried.
The end face electrode layer 16 is formed by firing with a profile of a peak time of 5 minutes and an IN-OUT time of 30 minutes. After further dividing into individual pieces, in order to improve solderability and reliability, Ni plating is performed on the exposed end surface electrode layer 16, and then solder plating is performed to form a plating layer 17.

According to this embodiment, by using a metal-organic paste as the marking paste, the film thickness of the marking characters 15 can be made 0.1 μm, compared to the conventional marking of 10 μm.
This is 1/100 compared to the previous year. This eliminates unevenness on the outermost surface of the chip resistor, which greatly reduces suction during automatic mounting, making it possible to provide a chip resistor with excellent mounting performance.

In this example, the firing temperature of the thick film resistor paste and the Ag-based thick film electrode paste was set at 850°C.
The firing temperature of the overcoat glass paste, the metal-organic paste for marking characters, and the end electrode paste was increased to 60℃.
Although the firing temperature was set at 0°C, this does not limit the firing temperature. Further, although the marking paste and the end face electrode were formed by firing separately, it is also possible to form them by firing them at the same time. Further, although the metal-organic paste for stamping characters is mainly composed of Au, it may be a metal-organic paste based on a metal such as Cr that exhibits a black color after firing, or a noble metal such as Pt.

Further, in this embodiment, a secondary coat glass for protecting the stamped characters was not applied on the stamped characters, but it may be applied, and there is no particular limitation.

Further, in this embodiment, a thick film material is used for the electrodes and the resistor, but a thin film or a metal organic material formed using a sputtering method, a vacuum evaporation method, or the like may be used.

[0015]

[Brief explanation of the drawing]

FIG. 1: (a) Top view of a chip resistor in one embodiment of the present invention; (b) Cross-sectional view of a chip resistor in the same embodiment.

[Figure 2]
Manufacturing process diagram of the chip resistor in the same example

[Figure 3] Cross-sectional view of a conventional chip resistor

[Explanation of symbols]

11 Insulating substrate 12 Thick film electrode 13 Thick film resistor 14 Primary coat glass 15 Seal characters 16 End electrode 17 Plating layer

Claims (1)

[Claims] 1. An insulating substrate, a pair of electrodes formed on the insulating substrate, a resistor formed to be connected to the electrode, and a glass film formed on the resistor. A chip resistor comprising a stamp made of a metal organic material formed on the glass film.