JP2790343B2 - Manufacturing method of chip resistor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a chip resistor provided with a display unit on which a resistance value or the like is printed.

[Conventional technology]

Conventionally, this type of chip resistor is manufactured as follows.

First, prepare a green sheet in which a slurry made of ceramic powder mixed with a binder resin and the like is formed in a thin plate shape,
Vertical and horizontal dividing grooves are formed in the green sheet by pressing and then fired to obtain a hard ceramic substrate. Next, as shown in FIG. 6, an Ag paste or an Ag / Pb paste is printed and formed at a position straddling one of the vertical and horizontal division grooves 2 and 3 of the ceramic substrate 1 to form an electrode 4.
After the resistor 5 is printed and formed at the position connecting the pair of electrodes 4 and 4 and laser trimmed, a glass material or a resin coating material is printed and formed at the position where the resistor 5 is covered to protect the resistor 5. Make coat 6. And, as shown in FIG.
After using a marking paste of the same series as the protective coat 6 with a different pigment, a display portion 7 such as a numeral or a character indicating the resistance value or the history information is printed and formed on the surface of the protective coat 6, and then the ceramic substrate 1 is divided into divided grooves. The wafer is divided along lines 2 and 3 and subjected to necessary processing such as plating to obtain a single chip resistor 10 as shown in FIG. The electrodes 4 are formed on the back surface of the ceramic substrate 1 before the division, and are formed on the side surfaces along the division grooves 2 after the division. Reference numeral 8 in FIG. 8 denotes a plating layer formed for preventing silver cracking of the electrode 4 and ensuring solder wettability.

After the chip resistor 10 manufactured in this manner is wrapped in a tape, as shown in FIG. The display unit 7 that shows the resistance value and the like is exposed on the top surface of each chip resistor 10 after mounting.

[Problems to be solved by the invention]

By the way, the chip resistance has been increasingly reduced in recent years, but since the display unit 7 cannot be made too small in view of visibility, the display unit 7 is relatively large exposed on the surface of the protective coat 6. And as a result,
As shown in FIG. 8, the suction resistance 11 of the automatic mounter has to be sucked and chucked by the chip resistance 10 in a state where the suction nozzle 11 is over the numeral or the like of the display unit 7. However, as described above, the conventional chip resistor 10 has the display portion 7 formed by printing on the surface of the protective coat 6. Therefore, the thickness of the display portion 7 causes the distance between the suction nozzle 11 and the protective coat 6 during the chucking. The gap 12 is created and air leaks easily occur,
There was a danger that this air leak would cause a poor chucking.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above-mentioned problems of the prior art and to provide a chip resistor which is less likely to cause a chucking failure.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, a protective coat having a concave portion conforming to the shape of a display portion is formed by printing at a position covering a resistor, and a paste (marking paste) for the display portion is formed in the concave portion. By performing printing to fill in (3), the inside of the concave portion serves as a display portion.

[Action]

According to the above means, since the surface of the display unit provided in the concave portion of the protective coat is substantially the same as the surface of the protective coat, suction chucking is performed with the suction nozzle of the automatic mounter over the display unit. Even if it is performed, air leakage hardly occurs, and it is possible to avoid a poor chucking.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a chip resistor according to an embodiment of the present invention, and FIGS. 2 to 5 are explanatory views showing the steps of manufacturing the chip resistor, corresponding to FIGS. 6 to 8. Have the same reference numerals.

In a chip resistor 10 shown in FIG. 1, a concave groove 9 extending in a predetermined numeral shape is provided in a protective coat 6 covering a resistor 5, and the concave groove 9 is filled with a marking paste. The display portion 7 having the same shape as the groove 9 is exposed on the top surface. Since the surface of the display unit 7 is substantially flush with the surface of the protective coat 6, the top surface of the chip resistor 10 can be regarded as almost flat. The configuration of the chip resistor 10 which is not particularly described is the same as that of the conventional product described above.

The method of manufacturing the chip resistor 10 is the same as that of the prior art up to the step of printing and forming the electrode 4 and the resistor 5 on the ceramic substrate 1 before division and laser trimming. Using a mask 13 as shown, lead borosilicate glass is printed at the position where the resistor 5 is to be coated, and after drying, it is fired to form a protective coat 6 as shown in FIG. That is, the mask 13 is obtained by coating an emulsion 13a on a mesh-shaped screen made of stainless steel or the like except for a portion corresponding to the shape of the protective coat 6.
Since a part of the screen is coated with a numeral-shaped emulsion 13a conforming to the shape of the display unit 7 to be printed later, the protective coat 6 formed by printing using the mask 13 is formed.
Is formed with a concave groove 9 conforming to the shape of the display unit 7. However, the depth of the concave groove 9 reaches the surface of the resistor 5 in the printing stage, but a small amount of the surrounding glass material flows in the subsequent drying / firing stage. It is shallow as shown.

After the protective coat 6 having the groove 9 of a predetermined shape is formed by printing in this manner, printing is performed by filling the groove 9 with a marking paste mainly composed of a glass material using a mask 14 as shown in FIG. This is dried and baked to form a display portion 7 having a predetermined numeral shape as shown in FIG.
That is, the mask 14 used here is formed by coating the emulsion 14a on a mesh-shaped screen except for the portion corresponding to the numeral shape of the display unit 7. For example, the mask 14 is formed by using a known technique by image processing. By positioning the 14 on the ceramic substrate 1, printing can be performed in the concave groove 9 with extremely high accuracy, and the surface of the display unit 7 can be made flush with the surface of the protective coat 6.

Then, after the display portion 7 is formed by printing, the ceramic substrate 1 is divided along the vertical and horizontal dividing grooves 2 and 3, and necessary processing such as plating is performed to obtain a single chip resistor 10 as shown in FIG. Get.

Since the chip resistor 10 manufactured in this manner has an almost flat top surface, almost no air leakage occurs even if suction chucking is performed with the suction nozzle of the automatic mounter closed to the display unit 7. This does not occur, that is, air leakage caused by the thickness of the display unit, which has been a problem in the past, is avoided, and the occurrence rate of chucking failure during mounting can be significantly reduced.

The shape of the display unit 7 is not limited to a numeral, but may be a character or a symbol.

Further, as a material of the protective coat 6 and the display unit 7, a resin-based coating material such as epoxy may be used.

〔The invention's effect〕

As described above, according to the present invention, the inside of the concave groove is formed as a display unit by filling the concave groove of the protective coat with the marking paste, and the surface of the display unit is substantially flush with the surface of the protective coat. Thus, even if suction chucking is performed while the suction nozzle of the automatic mounter is over the display unit, almost no air leakage occurs, and therefore, a chipping resistance that is less likely to cause a poor chucking and is suitable for automatic mounting is provided. Can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a chip resistor according to one embodiment of the present invention,
2 to 5 are views for explaining the method of manufacturing the chip resistor. FIG. 2 is a plan view of a mask used for printing a protective coat, and FIG. 3 is a cross section showing a state where the protective coat is printed. FIG. 4, FIG. 4 is a plan view of a mask used for printing the display unit, FIG. 5 is a plan view showing a state where the display unit is printed, and FIG. 6 to FIG.
FIG. 6 is a plan view showing a state in which a protective coat is printed in a manufacturing stage, FIG. 7 is a plan view showing a state in which a display section is printed in a manufacturing stage, and FIG. It is sectional drawing which shows the state which performs. 1 ... ceramic substrate (insulating substrate), 4 ... electrode, 5 ...
... Resistor, 6... Protective coat, 7... Display part, 9... Concave groove (recess), 10.

Claims (1)

(57) [Claims] After printing an electrode and a resistor on an insulating substrate,
Masking printing a protective coat having a concave portion of a predetermined shape on the surface at a position to cover the resistor, and then performing masking printing to fill the concave portion with a paste for a display unit. Production method.