JP2718178B2 - Manufacturing method of square plate type thin film chip resistor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a square plate type thin film chip resistor.

2. Description of the Related Art In recent years, as the demand for “light, thin and short” electronic devices has been increasing more and more, in order to increase the mounting density of resistance elements on circuit boards, small, square-plate chip resistors that can be surface-mounted have been developed. It is increasingly used. In recent years, the precision of parts and the noise have been reduced, and the demand for square-plate type chip resistors from a thick film type to a thin film type with high accuracy and low noise has been increasing.

FIG. 4 shows an example of a method of manufacturing a conventional small square plate type thin film chip resistor.

First, the conventional manufacturing process starts a substrate receiving process A for receiving a heat-resistant insulating substrate 21 made of a high-purity alumina substrate or the like.
An etching process C for shaping the thin film resistor 22 into a resistance pattern 23 through a sputtering process B for forming a thin film resistor 22 of -Cr or the like; To perform an atmosphere heat treatment step D at a temperature of 350 ° C. to 400 ° C. Then, to correct the resistance value of the resistance pattern to a predetermined value, by laser trimming method, etc.
The resistance value correcting step E is performed. Further, in order to protect the resistance pattern 23, a protective coat forming step F for forming a thermosetting resin film 25 is performed. Next, as a preparation step for dividing the insulating substrate 21 and forming the end face electrode layer 26, a scribing step G of forming a groove 27 for division on the insulating substrate 21 and a strip-shaped substrate 21 ' A primary substrate dividing step H is performed, and an end face electrode forming step I for forming an end face electrode layer 26 is performed on the end face of the strip-shaped substrate 21 'by using sputtering or the like. Then, as a preparation step for applying the plating layer 28 to the exposed resistance pattern and the end face electrode surface, a secondary substrate dividing step J for dividing the strip-shaped substrate 21 ′ into individual substrates 21 ″.
And an electrode plating step K for forming an electrode plating layer 28 in order to prevent the exposed resistance pattern and the end face electrode layer from being eroded during soldering and to ensure the reliability of solderability. The plate type thin film chip resistor is completed.

Problems to be Solved by the Invention However, the square-plate type thin film chip resistor according to this process has the following problems.

(1) Since the resistive film is formed by sputtering, continuous processing is difficult, and a large number of sputtering devices are required for mass production, and the cost is about twice as high as that of a thick-film chip resistor.

(2) Since the heat treatment of the resistive film is performed at 350 ° C to 400 ° C, about 50
Since a glass protective coat that requires heat treatment at 0 ° C. or higher cannot be used, a resin protective coat must be used. Therefore, the heat resistance is inferior to that of a thick-film chip resistor.

(3) Substrates with split grooves, which are often used for thick-film square-plate type chip resistors, are difficult to form a thin film because of the inherent undulation of the substrate between the split grooves. In the thin film chip resistor, grooves for division are formed by laser scribing on a substrate having no division grooves with little undulation. However, the laser scribe not only impairs the aesthetics of the chip resistor, but also has a problem that microcracks on the substrate are likely to occur due to thermal shock of the laser, which may cause insulation deterioration.

The present invention solves such problems at once, and provides a square plate type thin film chip resistor that is inexpensive, has good heat resistance by using a glass coat, and has excellent substrate insulation. is there.

Means for Solving the Problems In order to solve the above problems, a method of manufacturing a square plate type thin film chip resistor according to the present invention comprises a step of printing and firing an undercoat glass to smooth the surface of a heat resistant insulating substrate. And forming a thin film resistor on the undercoat glass, printing and baking a resistance material made of a metal organic material, and chemically stable to form an electrode for connecting the resistor. Printing and firing a conductive material;
A step of printing and baking an overcoat glass to cover and protect the resistor, a step of correcting a resistance value to make the characteristics of the resistor uniform, and a preparation step of forming an end face electrode. The dividing step and the end face electrode printing and baking step for forming electrodes on the end face of the divided substrate, the secondary board dividing step which is a preparation step for electrode plating, the prevention of electrode erosion by soldering, and the reliability of solderability And an electrode plating step for ensuring the above.

Operation As a result, the following operation is obtained.

(1) Since a thin film resistor can be formed continuously by a printing machine and a belt-type continuous firing furnace without using a sputtering apparatus,
The manufacturing cost is reduced, and an inexpensive square-plate thin-film chip resistor comparable to a thick-film square-chip chip resistor can be provided.

(2) Since the thin-film resistor is printed and fired with a resistance material made of a metal organic substance, a glass coat can be used as a protective coat, and the heat resistance can be improved as compared with a conventional square-plate thin-film chip resistor. .

(3) The undercoat glass absorbs the undulation of the substrate between the divided grooves peculiar to the divided grooved substrate, and makes the surface smooth. For this reason, it is not necessary to form a dividing groove by performing laser scribe on a smooth substrate having no undulation as in the related art, so that the insulating property of the substrate is improved.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a process chart showing an embodiment of a method of manufacturing a square plate type thin film chip resistor according to the present invention, FIG. 2 is a sectional view of a product manufactured by the process of FIG. 1, and FIG. It is explanatory drawing which shows the heat resistance of a square-plate type thin film chip resistor.

First, a process A for receiving a 96 aluminum substrate 1 having excellent heat resistance and insulation properties was performed. This alumina substrate 1
Is formed with a groove 2 (molding at the time of a green sheet) for division into strips and individual pieces. Next, in order to smooth the undulations and protrusions on the substrate,
Screen printing of undercoat glass paste, belt-type continuous firing furnace at 900 ° C peak 15 minutes, IN
Step B was performed in which the undercoat glass layer 3 was formed by firing with a profile of -OUT 2 hours. next,
On the three layers of the undercoat glass, a resistance paste made of a metal organic material containing RuO ₂ as a main component was screen-printed. Then, in order to skip only the organic components of the metal organic resistance paste and bake only the metal components onto the undercoat glass layer, a profile of 10 minutes at peak temperature of 640 ° C and 45 minutes at IN-OUT time was conducted by a belt type continuous firing furnace. And the step C of forming the resistor layer 4 was performed. Next, a thick-film silver paste is screen-printed so as to overlap a part of the resistor layer 4 and baked in a belt-type continuous baking furnace at a temperature of 600 ° C. with a profile of IN-OUT 45 minutes with a peak time of 6 minutes. Step D of forming the upper electrode layer 5 was performed. Further, in order to protect the resistor layer 4, an overcoat glass paste is screen-printed so as to completely cover the resistor layer 4, and a belt-type continuous firing furnace is used at a temperature of 600 ° C. for a peak time of 15 minutes. IN−OUT
Step E of baking with a baking profile of 90 minutes to form the overcoat glass layer 6 was performed. Next, in order to make the resistance value of the resistor layer 4 between the upper electrode layers 5 uniform, the resistance layer 4 is irradiated with laser light (oscillation frequency: 5 kHz, output: 0.3 W) passing through the overcoat glass layer 6. Only by destroying, only the resistance value correcting step F was performed. Next, as a preparatory step for forming the end face electrodes, a primary substrate dividing step G was performed to divide the alumina substrate 1 into strips and obtain a strip alumina substrate 1 'in order to expose the end face electrodes. Further, a thick-film silver paste is applied to a side surface of the strip-shaped alumina substrate 1 'by a roller so as to overlap a part of the upper electrode layer 5, and a belt-type continuous firing furnace is used at a temperature of 600 ° C. for a peak time of 6 hours. Min, IN
An end face conductor paste printing / firing step H was performed in which the end face electrode layer 8 was formed by firing with a firing profile of -OUT 45 minutes. Next, as a preparation step of the electrode plating step J, a secondary substrate division step J of dividing the strip-shaped alumina substrate 1 ′ on which the end face electrode layer 8 has been formed into individual pieces is performed. Finally, in order to prevent electrode erosion during soldering of the exposed upper surface electrode layer 5 and end surface electrode layer 8 and to secure the reliability of soldering, Ni, Sn-Pb was electrolytically plated. An electrode plating step J for forming the plating layer 9 was performed.

Through the steps described above, a square plate type thin film chip resistor according to the embodiment of the present invention was experimentally manufactured.

Variations in resistance values, resistance temperature characteristics (TCR), current noise characteristics, and changes in resistance values due to a heat resistance test (450 ° C. for 10 minutes) of the square plate type thin film chip resistor according to the embodiment of the present invention are compared with those of the conventional square plate type thin film chip. It is shown in comparison with a resistor. As a result, it was found that the resistance variation, TCR, and current noise characteristics were equivalent to those of the conventional square-plate thin-film chip resistor. In addition, as shown in FIG. 3, it can be said that the heat resistance is superior to the conventional square plate type thin film chip resistor.

In the examples, the firing temperature of the undercoat was set to 900
℃, the sintering temperature of the metal organic resistance paste is 640 ℃, the sintering temperature of the upper surface conductor is 600 ℃, the sintering temperature of the overcoat glass paste is 600 ℃, the sintering temperature of the end surface conductor paste is 6
The temperature was set to 00 ° C., but this does not limit the firing temperature.

Further, the metal-organic resistance paste used was a resistance paste mainly composed of RuO ₂ , but may be a Ni—Cr-based or noble metal-based paste, or any metal-organic resistance paste.

Although the upper electrode layer and the end face electrode layer use a silver-based thick film electrode paste, this may be a base metal-based thick film electrode paste such as gold, platinum, or copper.

As is clear from the above description, the present invention provides a step of printing and firing an undercoat glass to smooth the surface of a heat-resistant insulating substrate, and forming a thin film resistor on the undercoat glass. Printing and firing a resistive material made of a metal organic material, printing and firing a chemically stable conductive material to form an electrode for connecting the resistor, and coating the resistor. A step of printing and firing an overcoat glass for protection and protection, a step of correcting a resistance value for equalizing the characteristics of the resistor, and a step of dividing a primary substrate as a preparation step for forming an end face electrode and the division thereof An end face electrode printing and baking step for forming an electrode on the end face of the board, a secondary board dividing step which is a preparation step for electrode plating, and prevention of electrode erosion and soldering by soldering. Since the method includes an electrode plating step for ensuring the reliability of the attachment, the following effects can be obtained.

(1) Since a thin film resistance film can be continuously formed by a printing machine and a belt type continuous firing furnace without using a sputtering apparatus,
The manufacturing cost is reduced, and an inexpensive square-plate thin-film chip resistor comparable to a thick-film square-chip chip resistor can be provided.

(2) Since the thin film resistor is printed with a resistance material made of a metal organic material and baked at a high temperature, a glass coat can be used as a protective coat, and the heat resistance is improved as compared with the conventional square plate type thin film chip resistor. Can be achieved.

(3) The undercoat glass absorbs the undulation of the substrate between the divided grooves peculiar to the divided grooved substrate, and makes the surface smooth. For this reason, it is not necessary to form a dividing groove by performing laser scribing on a smooth substrate having no undulation as in the related art, so that the insulating property of the substrate is improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a manufacturing process of a square plate type thin film chip resistor according to the present invention. FIG. 2 is a sectional view of a sample manufactured by the method of manufacturing a square plate type thin film chip resistor shown in FIG. 3
FIG. 4 is an explanatory diagram showing the heat resistance of the rectangular plate type thin film chip resistor of the present invention, and FIG. 4 is an explanatory diagram showing an example of a manufacturing process of a conventional rectangular plate type thin film chip resistor. 1 ... 96-alumina substrate, 1 '... strip-shaped 96-alumina substrate, 1 "... individual-piece 96-alumina substrate, 2 ... grooves for division, 3 ... undercoat glass layer, 4 ... resistor Layer 5, top electrode layer, 6 overcoat glass layer, 7 trimming groove, 8 end electrode layer, 9 electrode plating layer.

Claims (2)

(57) [Claims] 1. A step of printing and baking an undercoat glass to smooth the surface of a heat-resistant insulating substrate, and printing a resistance material made of a metal organic material on the undercoat glass to form a thin film resistor. And baking, printing and baking a chemically stable conductive material to form an electrode for connecting the resistor, and printing overcoat glass to cover and protect the resistor. Baking step, a resistance value correcting step for making the characteristics of the resistor uniform, and a primary substrate dividing step which is a preparation step for forming an end face electrode and an electrode for forming an end face portion electrode of the divided board. Electrode plating to prevent electrode erosion by soldering and to secure the reliability of solderability by dividing the secondary substrate, which is a preparation process of electrode plating, into a secondary substrate dividing process, which is a preparation process of electrode plating. Method for producing a square plate-type thin film chip resistor is characterized in that a degree. 2. The square plate type thin film according to claim 1, wherein the resistance value is corrected by destroying a part of the resistor covered by the overcoat with a laser beam transmitted through the overcoat glass. Manufacturing method of chip resistor.