JPH01319902A - Chip resistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a chip type fixed resistor.

Conventional technology In recent years, with the increasing demand for electronic devices to be lighter, thinner, and smaller, extremely small chip resistors are increasingly being used as fixed resistors in order to increase the wiring density of circuit boards. It's here.

The structure of a conventional small chip resistor is shown in FIG. (
Latest Surf Is Mount Technology published by Kogyo Kenkyukai p27-p33) Conventional small chip resistors have a base material made of a fired 96 alumina substrate 6 and a top electrode layer 7 made of a mug-based thick film electrode.
It consists of an end surface electrode layer 8, a resistance layer 9 made of a ruthenium-based thick film resistor that overlaps a part of the top electrode layer 7, and an insulating glass pattern layer 10 made of lead borosilicate glass that covers the resistance layer. Note that N1 and 5n-Pb plating layers are electrolytically plated on the exposed electrode surface to improve solderability.

Problems to be Solved by the Invention However, since conventional small chip resistors were based on fired 96 alumina substrates, the top electrode layer and end electrode layer could only be formed by melting the glass component in the λg-based electrode paste. It was baked onto a 9e alumina substrate. Therefore, there was a problem in that the adhesive strength between the top electrode layer and the end electrode layer was weak.

The present invention solves these problems and aims to strengthen the adhesive strength between the 96 alumina substrate, the top electrode layer, and the end electrode layer.

Means for Solving the Problems The chip resistor of the present invention has a capacity of 2□0. A conductor electrode is an Ag-based thick film electrode formed by co-firing a low-temperature fired ceramic with a lead/borosilicate glass ratio of 40/6 o to e o/40 as a base material, and is co-fired with the base material. A ruthenium-based thick film resistor formed by partially overlapping with the base material and co-fired with the base material is used as a resistance layer.

As a result, it is possible to strengthen the adhesive strength between the low-temperature fired ceramic that is the base material, the top electrode layer, and the end electrode layer.

EXAMPLE Hereinafter, Example 1 of the present invention will be explained using FIG. 1.

v, 1, the chip resistor of the present invention is made of Al2O
3/Lead borosilicate glass ratio is 40/6o~80/
40 low-temperature-fired ceramic substrate 1 as a base material, λg-based thick electrodes formed by firing simultaneously with the low-temperature-fired ceramic substrate 1 are used as a top electrode layer 2 and an end electrode layer 3, and the top electrode layer 2, a ruthenium-based thick film resistor formed by co-firing with the low temperature fired ceramic substrate 1 is used as the resistance layer 4, and as a protective layer for the resistance layer 4, 2 parts of lead borosilicate glass and the low temperature The insulating glass pattern layer 5 is formed by firing separately from the fired ceramic substrate 1.

First, Table 1 shows the composition of the lead borosilicate glass used in Example 1.

(Left below) Table 1 This lead borosilicate glass was placed in a platinum crucible and 1
The mixture was heated and melted at 000°C for 3 hours with stirring. Next, this is pulverized and further milled to an average particle size of 2 μm to 3 μm.
It was crushed to look like this. - Mu12 with a purity of 98% or more
03 powder was pulverized using a pulverizer to have an average particle size of 3 μm to 4 μm.

Next, these AJ205 powders and glass powders were mixed in the proportions shown in Table 2, and three types of compositions according to the present invention (Human to C) were prepared.
I got it. Next, an acrylic organic binder was added to this composition, and the mixture was kneaded for 24 hours to form a slurry. Next, use this and a doctor blade to make a width of 2
Make a sheet of 0cm + 0.5mm thick and dry it for 50 minutes.
It was cut into a size of rrrm x 2 rran.

Next, an Ag-based conductor paste was screen-printed on top of this, the Ag-based conductor paste was applied to the end face with a roller, and after drying, a ruthenium-based resistance paste was further screen-printed and dried.

After that, the printed matter was de-piped in air at a temperature of 450°C.
Depyrining and firing were performed for 1 hour at a peak temperature of 900° C. to form a low-temperature fired ceramic substrate 1, a top electrode layer 2, an end electrode layer 3, and a resistance layer 4 at the same time.

Next, laser trimming was performed to correct the resistance value. Furthermore, after this, an insulating glass pattern layer 5 was formed by e-screen printing a low melting point lead borosilicate glass paste and baking it in air at 500°C for 1 hour (note that soldering on the exposed electrode surface improves the properties). Ni and 5n-P to
The plating layer b is applied by electrolytic plating). Regarding these chip resistors, the warpage of the element was measured in order to determine the electrode adhesion strength of the mug electrode, temperature coefficient of resistance (TCtR), and degree of deformation of the element. These results are listed in Table 2.

As a comparative example, similar tests were conducted on compositions other than those of the present invention, and the results are also described in the same manner. The method for measuring each characteristic is as follows.

Electrode adhesion strength A chip resistor is mounted on a printed circuit board, a tensile test is performed using a Butschdel gauge, the strength is measured when the electrode of the chip resistor peels off, and the value is converted to a value per area. was defined as the electrode adhesion strength.

Temperature Coefficient of Resistance (TCR) Mount the chip resistor on a printed circuit board and measure the resistance value at 25℃ (R25), then place it in a 126℃ atmosphere for 1 hour.
After leaving it for 0 minutes, measure the resistance value in that atmosphere.R12
5) The value calculated using the following formula is defined as the temperature coefficient of resistance (TCR).

Warpage of a chip resistor The warpage of a chip resistor is calculated using the following formula.

Warpage of chip resistor = Total thickness of chip resistor m - Thickness of pole layer - Thickness of resistance layer - Thickness of insulating glass pattern layer - Substrate thickness of low temperature sintered substrate Table, 2 It is clear from Table 2 As can be seen, the device according to the present invention has high electrode adhesion strength and is excellent in terms of TCR and chip resistance warpage.

The base material's MuJ20s/lead borosilicate glass ratio is 4.
If it is smaller than .degree./50 (the glass component is large), the glass component in the base material will seep out into the resistance layer during firing, leading to deterioration of TCH. Moreover, when the ratio of λB2O5/lead borosilicate glass of the base material exceeds 50/40, warping of the chip resistor occurs.

Next, Example 2 according to the present invention will be described.

In Example 2, three types of lead borosilicate glass powders (D
-F) was prepared, and this composition was mixed with Mu β20. The powders were mixed, an acrylic organic binder was added to the composition, and the mixture was kneaded for 24 hours to form a slurry. Next, this was made into a sheet with a width of 20 CWL and a thickness of 0.5 mm using a doctor blade.
After drying, it was cut into a size of 50 m x 2 m.

Next, a KAg-based conductor paste was screen-printed on top of this, a λg-based conductor paste was applied to the end face with a roller, and after drying, a ruthenium-based resistance paste was further screen-printed and dried.

Thereafter, the printed matter was de-piped and fired for 1 hour in air at a de-piping temperature of 450°C and a peak temperature of 800'C to 1000°C for 1 hour, thereby forming a low-temperature fired ceramic substrate 1 and a top electrode layer 2.
The end face electrode layer 3 and the resistance layer 4 were formed simultaneously.

Next, laser trimming was performed to correct the resistance value. Furthermore, after this, a low melting point lead borosilicate glass paste was screen printed and baked in air at 00°C for 1 hour to form an insulating glass pattern layer 6 (note that soldering on the exposed electrode surface improves properties) N1 and 5n-P to make
b) The plating layer is applied by electrolytic plating). For these chip resistors, the flexural strength and TCR of the base material were measured. These results are listed in Table 3.

As a comparative example, other than the composition of the present invention, the firing temperature was 80°C.
Similar tests were conducted for temperatures other than ~1000°C, and the results are also listed in Table 3.

Note that the method for measuring the bending strength is as shown below.

bending strength The bending strength was measured using a jig as shown in FIG.

That is, the chip resistor 11 was placed so as to bridge the recess 13a of the jig 13, and the chip resistor 11 was pushed with the push-pull gauge 12. The strength when a chip resistor breaks is defined as the bending strength.

Table 3 As is clear from Table 3, when the glass transition point of the lead borosilicate glass in the base material becomes less than 550°C, the glass begins to soften during the debinding process, and sufficient debinding is not achieved. As a result, the base material becomes extremely porous and the bending strength of the chip resistor decreases.

Furthermore, if the glass transition point of the lead borosilicate glass in the base material exceeds 650°C, sufficient firing at 1000°C or lower will not be possible, and the bending strength of the chip resistor will similarly decrease.

In addition, chip resistors fired at a firing temperature of less than 800'C have a lower bending strength of the base material due to insufficient sintering.
When the temperature exceeds 000° C., the resistance layer becomes oversintered and the resistance performance (TCR) deteriorates. Therefore, the firing temperature is 800°C
A range of ~1000°C is suitable.

In Examples 1 and 2, the lead borosilicate glass had the composition shown in Table 1, but the glass transition point was 550°C ~
Any lead borosilicate glass with a temperature of 650°C may be used. In addition, the glass powder is further processed into a pulverizer with an average particle size of 2 μm to 3 μm.
Although the particles were ground to a particle size of μm, the average particle size is not limited. - On the other hand, Mu1205 powder with a purity of 98% or more was pulverized using a pulverizer to give an average particle size of 3 μm to 4 μm VC, but this also does not limit the average particle size.

Furthermore, although a single doctor blade is used to form the sheet, other methods such as extrusion molding may also be used. Further, although insulating glass is used as the protective layer of the resistance layer in Example 1, a resin-based coating material may be used instead.

Effects of the Invention As is clear from the above explanation, the present invention
/Lead borosilicate glass ratio is 40/50 to 50/4
A low-temperature fired ceramic of o is used as a base material, an Ag-based thick film electrode formed by co-firing with the base material is used as a conductor electrode, overlaps a part of the conductor electrode, and is co-fired with the base material. Since it is constructed using a well-formed ruthenium-based thick film resistor as the resistance layer, it has excellent effects such as strengthening the adhesive strength between the low-temperature fired ceramic base material, the top electrode layer, and the end electrode layer. can get.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the structure of the chip resistor of the present invention, Figure 2 is a schematic diagram showing the method for measuring bending strength, and Figure 3 is a sectional view showing the structure of a conventional small chip resistor. be. 1...Low temperature firing ceramic substrate, 2...
・Top electrode layer, 3... End electrode layer, 4...
...Resistance layer, 5...Insulating glass pattern layer. Name of agent: Patent attorney Toshio Nakao and 1 other person1-
-ft! , 1st generation ℃ Rami Tsuku ink 2- yo atw layer 3- Hanawa i Electron mother dust l Fig. 2

Claims (2)

[Claims] (1) Al_2O_3/lead borosilicate glass ratio is 40
/60/40 low temperature fired ceramic as a base material, A formed by co-firing with the base material.
1. A chip resistor characterized in that a g-based thick film electrode is used as a conductor electrode, and a ruthenium-based thick film resistor that overlaps a part of the conductor electrode and is formed by co-firing with the base material is used as a resistance layer. (2) The glass transition point of the lead borosilicate glass in the base material is 550°C to 650°C, and the firing temperature of the base material is 800°C to 10°C.
The chip resistor according to claim 1, characterized in that the temperature is 00°C.