JPS5810843B2 - How to manufacture chip resistors - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing a chip resistor.

BACKGROUND ART Recently, electronic circuits have become more densely packaged, and as a result, electronic devices have become smaller, thinner, and lighter, and electronic components that meet these demands have been developed and are being used in the market.

One of these components is a chip resistor, but if you think about the current chip resistors from the standpoint of using them, there is room for improvement, and there is a strong demand from users to improve them.

The present inventors have invented a new method for manufacturing a chip resistor to meet those needs.

Hereinafter, a conventional method for manufacturing a chip resistor and a manufacturing method invented by the present inventors will be compared and described.

FIG. 1 shows an outline of the manufacturing process of a conventional chip resistor, and FIG. 2 shows an outline of the manufacturing process invented by the present inventors.

First, the conventional manufacturing process starts with a substrate process A in which a heat-resistant insulating substrate 1 such as a high-purity alumina substrate is received, and here the substrate 1 is provided with a slit 2 to facilitate division.

Next, in order to connect a resistor 4, which will be described later, to the surface of the substrate 1, a chemically stable conductive agent is printed and fired to form the electrode 3. A resistor printing and firing step C is performed in which resistor material is printed and fired to form the resistor 4 so that the resistors 4 are partially overlapped.

Next, a glass printing and baking process is performed to cover and protect the resistor 4 with a glass film 5, and the substrate 1 is divided along the horizontal slits 2 to prepare for forming end electrodes to be described later. A primary substrate dividing step E is performed.

Then, a final end-face electrode printing and baking step F is performed to form end-face electrodes 6 on the end faces of the divided substrate 1' obtained by dividing the primary substrate, and then electrodes are soldered onto the electrodes 3 and end-face electrodes 6. Electrode plating step G is performed to form a plating film 7 in order to prevent curling and maintain reliability of solderability.

Next, the divided substrate 1' is slit 2 in the direction of the vertical force.
A secondary substrate dividing step H is performed to divide the resistor into individual unmodified chip resistors 8 along the lines, and then a resistance value modifying step (2) is performed to make the characteristics of the resistor 4 uniform.

9 is a modified part 10 where the resistance value was modified from above the glass film 5.
The appearance condition of this finished product is a chip resistor with
Products that pass various check processes J for various electrical characteristics, etc. are sent to the market as non-defective products.

On the other hand, the manufacturing process of the present invention will be explained with reference to FIG. 2, with the same steps as above, the same symbols and numbers assigned to the same parts, and the following: Substrate receiving process A → Electrode printing and firing process B → Resistor printing and firing process C The process up to this point is the same as before.

In the present invention, the resistance value modification step (2) is performed after the resistor printing and firing step C, and the modified portion 10' is directly connected to the resistor 4.

Thereafter, a glass printing and firing process is performed, a primary substrate dividing process E is performed, and then an end face electrode printing and firing process F is performed.

Here, the resistance values of the individual resistors 4 have already been corrected in the divided substrate 11 as described above.

Next, a secondary substrate dividing step H is performed, and a single chip resistor product 11 without electrode plating is obtained.

Subsequently, an electrode plating step G is performed to form a plating film 7' on the electrode 3 and end surface electrode 6 of this single chip resistor product 11, and a completed chip resistor 12 is manufactured.

After that, non-defective products are sent to the market after going through various check processes.

The difference between the conventional manufacturing process and the manufacturing process of the present invention is that, as is clear from the above explanation, the order of the resistance value correction process I and the electrode plating process G is different.

That is, in the conventional process, the resistance value correction process (2) is the final process before the checking process J, as shown in FIG.

In addition, the electrode plating process G is performed after the end face electrode printing and baking process F.
This is a process in which electrode plating is performed in that state.

On the other hand, in the process of the present invention, as shown in FIG. 2, the resistance value correction step (2) is performed after the resistance printing and firing step (c).

Further, the electrode plating step G is a step in which electrode plating is performed after the secondary substrate dividing step H.

As described above, the manufacturing method of the present invention changes the conventional manufacturing process and the order of the steps, so that the structure and electrical characteristics of the chip fixed resistor are significantly different as described below.

Next, specific examples of comparisons of various characteristics between products manufactured by the process of the present invention and products manufactured by conventional processes will be shown below.

Comparative Example 1 As shown in FIG. 3, a metal piece 15 with a width of 2 m is placed in the center of the glass film (coated surface) 14 of the chip resistor 13, and a metal piece 15 with a width of 2 m is placed between the electrode part 16 of the chip resistor 13 and the metal piece 15. An alternating current voltage was applied, the voltage was increased at a rate of 50 V per second, and the voltage until breakdown was measured.

The results of the pressure resistance test on the glass membrane surface are shown in FIG. 4 (the number of samples was 20 in each case).

). As is clear from this result, the test result is 7 with X points.
The characteristic of chip resistors manufactured using the conventional process is that the resistance value is modified in the final process, so in order to modify the resistor, the glass coating must also be removed, exposing the resistor. The withstand voltage of the product is 250μ or less.

However, the characteristics of the chip resistor manufactured by the process invented by the inventors, whose test results are plotted with black dots, are that the resistor is completely sealed and has a structure that can sufficiently withstand dielectric breakdown caused by the voltage of the glass coating. The total price is 750■
It has a withstand pressure of more than

Comparative Example 2 A comparison was made in terms of accelerated life between a chip resistor manufactured using a conventional process and a chip resistor manufactured using a process invented by the present inventors.

That is, both of the above chip resistors (resistance value: 10Ω) were boiled in pure water, and the rate of change in resistance value was examined over time.

The accelerated life test results are shown in FIG.

The result is that for the same reason as mentioned in Comparative Example 1, the characteristic A of the chip resistor manufactured using the conventional manufacturing process is that the rate of change in resistance value is extremely low because the resistor is exposed. is clear.

In comparison, the characteristics of the chip resistor manufactured by the process invented by the present inventors have an extremely small rate of change in resistance value.

Comparative Example 3 1 Among the manufacturing processes of a chip resistor, the electrode plating process is different between the conventional process and the process invented by the present inventors, as described above.

The purpose of electrode plating is that the electrodes of chip resistors use a glaze-based conductive material, so if they are used as is, the soldering temperature may be high during soldering, or the soldering time may take longer. In such cases, a phenomenon occurs in which the electrodes get caught in the solder, so a metal plating such as copper or nickel that is resistant to solder is applied on top of the glaze-based conductive material, but these plating films alone cannot ensure reliability of soldering. Since it is difficult to do so, tin or solder plating is performed on the plating film.

However, if the plating method of the electrode portion of the chip resistor is different, the electrode structure will be different, and the characteristics will differ as shown below.

In order to clarify the differences in this custom-made product, we conducted the following tests.

That is, a 100-ohm chip resistor manufactured using the conventional manufacturing process and a 100-ohm chip resistor manufactured using the process invented by the present inventors were soldered onto a printed circuit board for chip resistor testing. It was connected to the copper foil of the substrate, and pure water was supplied onto each of the chip resistors until the chip resistors were completely submerged, and then a DC voltage of 20 V was applied for 60 seconds.

As a result, it was confirmed that the electrode material of the tick resistor manufactured using the conventional process was eluted on the positive side of the DC voltage.

On the other hand, it was confirmed that such a phenomenon did not occur in the chip resistor manufactured by the process invented by the present inventors.

The reason for this is that the electrode plating in the conventional manufacturing process does not have the same shape after the end face electrode printing and firing process as shown in Figure 1.
In other words, since the chip resistor is installed in a horizontally continuous state, and then the chip resistor is divided into individual pieces, the cross section is made of a brace type conductive material, rather than an alumina substrate.
This is because the nickel plating film and the solder plating film are exposed in layers in this order.

On the other hand, in the electrode plating process of the present inventors' invention, as shown in the process diagram of FIG. 2, electrode plating is performed after dividing the secondary board, that is, after dividing it into individual chip resistors. This is because the glaze-based conductive material is completely covered with a nickel plating film, and the nickel film is completely covered with a plating film that extends over the nickel film, resulting in a structure in which the glaze-based conductive material is completely sealed.

Comparative Example 4 The DC voltage was set to IOV in the same manner as Comparative Example 3, and the application time was varied from 5 minutes to 20 minutes, and each of the samples manufactured using the conventional manufacturing process and the manufacturing process invented by the present inventors was Ten chip resistors were tested under each test condition,
The elution state of the electrode material was investigated.

The results are shown in FIG. 6, and the number indicated by hatching indicates the amount of electrode material eluted.

As a result, the number of eluted electrodes increases over time in chip resistors manufactured using the conventional process shown in ``A'', but the above phenomenon does not occur in chip resistors manufactured using the process of the present invention shown in ``A''. It is clear that this has not occurred at all.

The characteristics of the chip resistor manufactured by the manufacturing process of the present invention are clear from the above comparative example and the manufacturing process diagrams of FIGS. 1 and 2, and the characteristics will be listed again below.

(1) Resistance value correction is carried out on an undivided board, making it easier and faster to measure resistance values, and when performing resistance value correction, since they are arranged regularly at regular intervals, the correction speed is faster. becomes very fast.

For example, when combined with a laser modification method, productivity can be improved by more than 10 times compared to conventional processes.

(2) Since there is no glass coating on the resistor, it is possible to correct the resistance element accurately, and the correction status can be confirmed accurately, and the energy and materials required for correction are lower than when the resistor is covered with glass. It requires less, leading to resource and energy savings.

(3) Since electrode plating is performed after dividing the chip resistor into individual chip resistors, conventional methods can be used for plating as is, and no special equipment is required, making it very economical.

(4) Since the glaze-based electrode part is completely sealed with a plating film, there is no damage to the electrode during soldering, and electrode elution after soldering is completely prevented.

(5) Since the resistance value is corrected before glass printing, the resistor can be completely coated with glass, and the resistor will not be affected by the atmosphere even in adverse environments, making it extremely reliable. Chip resistors can be manufactured.

(6) Since it combines features (4) and (5),
Soldering is possible regardless of the soldering conditions, and chip resistors can be mounted on either the front or the back (because the resistor is completely insulated with a glass coating).

(7) When displaying the product number on a chip resistor, it can be displayed on both the front and back sides.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing a conventional manufacturing process of a chip resistor, Fig. 2 is a schematic diagram showing a manufacturing process of a chip resistor according to the present invention, and Fig. 3 explains a method for measuring withstand voltage of a chip resistor. Figure 4 is a diagram comparing the results of the glass membrane surface pressure test of chip resistors obtained by the method of the present invention and the conventional method, and Figure 5 is a diagram showing the results of the accelerated life test (boiling test). The comparison diagram, FIG. 6, is a diagram also comparing the electrode material elution test results. DESCRIPTION OF SYMBOLS 1...Heat-resistant insulating substrate, 1"...Divided substrate, 3...Electrode, 4...Resistor, 5...Glass film, 6...End surface electrode, 7
'...Metallic film, 10'...Resistance correction part, 12...Chip resistor.

Claims (1)

[Claims] 1. A step of printing and firing a chemically stable conductive agent as an electrode for connecting a resistor on the surface of a heat-resistant insulating substrate, and a step of printing a resistive material to form a resistor so as to partially overlap the electrode. a step of printing and firing the resistor, a step of modifying the resistance value to match the characteristics of the resistor, a step of printing and firing glass to cover and protect the resistor and the resistance modifying portion with glass, and a step of forming the end electrode. a primary substrate dividing step which is a preparatory step, a final end surface electrode printing and firing step for forming electrodes on the end surfaces of the divided substrates, a secondary substrate dividing step which is a preparatory step for electrode plating, and a secondary substrate dividing step which is a preparatory step for electrode plating. A method for manufacturing a chip resistor, which comprises sequentially performing an electrode plating process to form a plating film on an electrode and to prevent the electrode from being bent during soldering and to ensure reliability of solderability.