JPS63272005A - Electric resistor and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain an electric resistor where its resistance value is stable, while it is inner-packaged at a multilayered substrate after laminating it together with base metal conductor materials and also it can be manufactured by burning in a reducing atmosphere by using burned bodies containing massive particles, needle particles that adhere on the above massive particles or come into existence nearby the above particles as well as a glass layer. CONSTITUTION:Substances consisting of burned bodies containing massive particles (b), needle particles (c) that adhere on the above massive particles (b) or come into existence nearby the above particles (b) as well as a glass layer (a) are used as an electrical resistor. Further, the massive particles (b) containing main body materials of the resistor which make up a main body of the electrical resistor are burned in non-oxidizing atmosphere and reduction of the surface of the massive particles which resulted from the above burning permits a reduced product of the needle particles (c) to adhere to the massive particles (b) or to manufacture the electric resistor through a process which makes the reduced product come into existence nearby the particles (b). The above mentioned massive particles (b) contain, for example, molybdate of more than a sort of alkali earth metals, Zn, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Zr, Hf, Nb, Ta, Mn and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a thick film type electrical resistor provided on a fixed chip resistor or a circuit wiring board, etc., and particularly to a thick film type electrical resistor that can be obtained by firing in a non-oxidizing atmosphere. Concerning possible electrical resistors.

Conventional technology The electrical circuits of electronic devices are often constructed by mounting various electrical elements such as resistors, capacitors, diodes, and transistors on circuit boards, but as electronic devices become smaller, these Circuit boards that can further increase the packaging density of electrical elements have come into widespread use.

The resistors installed on these circuit boards are either thick film resistors formed by printing and baking resistor material paste directly onto the circuit, or a pair of electrodes formed at both ends of a square plate-shaped ceramic chip. There are also fixed chip resistors in which the thick film resistor is formed so as to span both electrodes.

Conventionally, in order to provide such a thick film resistor on a circuit board,
For example, a conductive material paste such as Ag or a material such as iAg-Pd is applied to the surface of an alumina substrate obtained by firing at around 1500°C, and after baking, a paste containing, for example, Rung as a resistor material is screen printed. A common method is to apply the film by a method such as the above, then bake it at 750 to 850°C, and further adjust the resistance value by trimming or the like as necessary.

However, in recent years, electronic devices have become lighter, thinner, and smaller.
The demand for lower costs has become even stronger, and efforts are being made to further reduce the size and cost of circuit boards.

As a concrete measure for miniaturization of the former, firstly, the circuit board is multilayered, and secondly, a resistor is built inside. Examples of multilayered circuit boards include Ag or A.
Examples include multilayer wiring boards obtained by laminating and crimping ceramic green sheets (green sheets) printed with conductor material paste such as g-Pd, and then simultaneously firing them in the atmosphere at 800 to 1100°C; As an example of internalizing a resistor, a RuO2-based resistor material paste is further printed on a ceramic green sheet printed with the conductor material paste, laminated and crimped in the same manner as above, and then co-fired to obtain a resistor interior. Multilayer wiring boards and the like are known.

In addition, as a specific measure to reduce the cost of the latter, in place of expensive noble metal conductor materials such as Ag or Ag-Pd materials, inexpensive base metal conductor materials such as Ni or Cu can be used. These are co-fired with green ceramics at 800-1100℃ in a neutral or reducing non-oxidizing atmosphere such as nitrogen gas or nitrogen gas containing hydrogen, which can avoid high resistance due to oxidation. Multilayer wiring boards obtained by this method have been put into practical use. Furthermore, as described in Japanese Patent Application Laid-Open No. 56-153702, a resistor material made of Mo5iz-TaSiz and glass is coated on an alumina substrate having an F4 <cu> conductor, and the thickness obtained by heat treatment is Film resistors and the like are also known.

Problems to be Solved by the Invention However, in order to reduce the size and cost of circuit boards at the same time, it is necessary to co-fire a resistor material made of Mo5iz-TaSiz and glass with a green ceramic sheet in a non-oxidizing atmosphere. , warpage may occur in the fired body due to the difference in expansion rate and contraction rate between the two, and Mo5iz-
There is a problem that gas is generated due to the decomposition reaction of TaSi, which tends to cause blisters in the fired body. In order to improve this, an example is known in which a resistor material made of MoS i 2-metal fluoride (e.g. calcium fluoride) and glass is used, as described in JP-A-60-198703. There is no warping or blistering during firing as mentioned above.

However, when a thick film resistor obtained by coating a resistor material made of Mo5tz-metal fluoride and glass on a green ceramic sheet and co-firing it for 1000 hours in 95% relative humidity, the resistance of 5 to 10 % increase in resistance value is observed, and the prescribed function as a resistor cannot be performed.

Further, when the RuO□-based resistance material is co-fired with green ceramic in an antibody material gas or a nitrogen gas atmosphere containing hydrogen, a reduction reaction occurs, resulting in a low resistance value and no longer exhibiting characteristics as a resistor.

There is a problem with this RuO□-based resistance antibody material when it is fired in a non-oxidizing atmosphere, but when it is fired in an oxidizing atmosphere, it has an appropriate resistance value as a resistor, and its resistance A thick film resistor made of molybdenum oxide is known as a thick film resistor whose value changes little over time. However, this resistor cannot be co-fired with green ceramic at a temperature of 800 to 1100°C because molybdenum oxide sublimes at a temperature of 800°C or higher.

For this reason, it has been desired to develop a thick film resistor that has the same performance even when fired in a non-oxidizing atmosphere as when fired in an oxidizing atmosphere.

An object of the present invention is to provide an electrical resistor that can not only be used in fixed chip resistors or general circuit boards, but also can be laminated with base metal conductive materials and incorporated into multilayer boards, and which has stable resistance values. Not only is it a resistor, but
The object of the present invention is to provide an electrical resistor that can be manufactured by firing the resistor material in a reducing atmosphere.

Another object of the present invention is to provide a manufacturing method that can further improve the characteristics of the electrical resistor.

Means for Solving the Problems ゛In order to solve the above problems, the present invention provides a method that includes lump particles, acicular particles attached to the lump particles or existing in the vicinity of the lump particles, and a glass layer. The present invention provides an electrical resistor characterized by having a fired body.

The present invention also provides a method for firing the bulk particles containing the resistor body material constituting the electric resistor body in a non-oxidizing atmosphere, reducing the surface of the bulk particles, and converting the reduction product of the acicular particles into the bulk particles. The present invention provides a method for producing an electrical resistor, which includes a step of adhering to particles or making them exist near the bulk particles.

Next, the present invention will be explained in detail based on drawings and photographs.

The electrical resistor of the present invention has lumpy particles and acicular particles, such as a structure in which spherical particles and acicular particles C are dispersed in glass a, as shown in FIG. In this example, the acicular particles are attached to or in the vicinity of the spherical particles. Such a structure allows electrical current to flow through spherical particles and needle-like particles that are in contact with or in close proximity.

Such a structure can be formed, for example, by firing bulk particles of the resistor material and growing a product on the surface into a needle shape.

As such a resistor material, at least one type of molybdic acid from at least one of the following groups (A) to (G) can be used, and specifically, the following may be mentioned.

(A) Alkaline earth metal molybdate When Me is an alkaline earth metal, the general formula MeMoO,, Mef
fMOO6, Met'11005, MetMot, M
eMo4.0+*, MgMo0z4, MeMosO+o
, MgMo0a, MetMOxOrr, etc. are preferred. Specifically, for example, MgMo0a, Ca
Mo0o, SrMo0. , BaMoO4, BaMozO
t, BaMOaO++, BaMo70z4, BaMo
70z4, CaMo0o0, NgffiMo2Q. etc.

Further, the following complex molybdates are also exemplified.

(Mgg Cay) MOO4, where x + y = 1
, (Caw Sry) MOO4, where x + y-1
, (MgX Ba, )Mo04, however, X -1-y
-1, (MgX Ca, Ba, )MOO4, however,
X +y +2 = 1, (CaXSr, Bag)M
OO4, however, x + y + z = 1% (Mgx C
a, Srt Ra1. , ) MOO4, however, X +y
+z +z = 1, (Ca, Sry)Moth
, however, x + y = 3, (sr, Bay )MOO
& , where x + y = 3, CB) Zinc molybdates such as ZnMoO4, ZnMOt07, ZnJotO
An example is q.

(C) Y, La, Ce, Pr5Nd, Sm, E
u5Gd, Tb, Dy, 110% Er, Tl1%
Examples of molybdates of each element of Ybs Lu and composite molybdates of multiple atoms thereof include the following.

・Also, (Y* Ce, )Moist, however x+
y = 6,'(Pr, Buy) Moist However, x+y = 6, (Gd, IDyy)? 100+z
However, x+y = 6, (La, Ndy Tbg)Mo
ist However, x + y + z = 6 (Ilo, Tm,
Composite molybdates consisting of multiple elements such as Yb, )Mo0.1, however, x+y+z=6 are also included.

(D) Molybdate of aluminum, e.g. Al
, Mo, 0. □ is mentioned.

(E) Molybdates of each element such as zirconium and hafnium, and composite molybdates thereof such as ZrM
ozOa, H'fMOzOs, (Zr, Hy)
MozOIlHowever, x +y-1 is mentioned.

(F) Molybdates of each element such as niobium and tantalum, and composite molybdates thereof such as NbJozO+4, Ta2M0:+Ot4, (N
b, Ta, )MO2014, however, x + y = 1
can be mentioned.

(G) Manganese molybdate For example, MnMo0. can be mentioned.

Molybdates belonging to each of the above groups can be synthesized by heat treatment of oxides of the respective elements and molybdenum oxide (Moss), but they can also be synthesized by heat treatment using their precursors. For example, a molybdate of an alkaline earth metal can be prepared by mixing a substance serving as a precursor of each metal oxide of an alkaline earth metal with molybdenum oxide (MOO3) or its precursor at a predetermined molar ratio, and then heat-treating the mixture. For example, calcium carbonate (CaC
O*) or calcium hydroxide (Ca (OH) z) and molybdenum oxide (MOO:l) or its precursor,
For example, molybdic acid (IIZMOO4) is mixed in a predetermined molar ratio and heat treated.

The heat treatment conditions at this time were 600 to 1000°C;
Examples include 1 to 3 hours.

In the present invention, in addition to the above-mentioned molybdate, tungsten carbide (WC), which can be made into a resistor by growing needle-like particles from its block-like particles, can be used.

In the present invention, it is preferable to use a binder, and a glass is used for this, and a commonly known glass can be used, and the glass is not limited to a specific composition, but Pb20a ,B,kzOx
Oxides such as , 5nO1s, and CdO may be reduced and metallized when the resistor material containing them is fired in a non-oxidizing atmosphere, and this metal changes the resistance value. It is preferable not to contain these oxides in cases where it is undesirable for such occurrence to occur.

Glass components include 5i02, B2O2, ZnO, C
aO1S'0, zrOt, etc. are preferred, and the composition ratios of these oxides are: SiO□12-33 wt% agos 20-35 wt% ZnO or Sr0 13-33 wt%Ca0 10
~25% by weight Zr0t 15-45% by weight is preferred.

In order to manufacture glass from a composition of these oxides, the respective oxides are weighed and mixed to achieve the above composition ratio. This mixture is placed in a crucible and melted at a temperature of 1200 to 1500°C, and then the melt is poured into water, for example, and rapidly cooled to obtain coarse glass powder.

Glass powder is obtained by pulverizing this coarse powder to a desired particle size (for example, 10 μm or less) using a pulverizing means such as a ball mill or a vibration mill.

In the above, a mixture of pure oxides was used, but the glass is not limited to this, as long as the result is a mixture of each oxide. It may be melted to make glass. For example, CaO (calcium oxide) is CaC03 (calcium carbonate), BzO*
(Boron oxide) can be obtained by heat treatment of boric acid (HJ(h), so CaCQ, , H!BO, respectively, can be used instead of part or all of CaO, IhO*, respectively.

can be used. The same applies to oxides of other components.

The lumpy particles of molybdate of the elements of the above element group and glass powder obtained as described above may be mixed and used as is as a resistor material, but they may be heat-treated and pulverized to be used as a resistor material. The heat treatment temperature is preferably 800°C to 1200°C, and if the temperature is outside this temperature range, the resistor material is processed into an electrical resistor. The resistance value of the finished resistor is easily affected by subtle fluctuations in the composition ratio due to process working conditions, etc., and it is difficult to stably obtain a desired resistance value. This heat treatment is preferably carried out in a non-oxidizing atmosphere, and it is preferable to use nitrogen gas or other active gas, or a mixed gas containing these gases and hydrogen gas.

In order to create a resistor for a fixed chip resistor or a thick film resistor from the resistor material powder thus obtained, the resistor material powder is applied to, for example, a ceramic green sheet and fired. At this time, it is preferable to use the molybdate, etc., which will become the main body of the electrical resistor, after forming it into bulk particles such as spherical, elliptical, and polygonal bodies. This is because it is preferable that the original mother body remain. A binder such as glass may also be used to form the resistor body material into bulk particles.

In order to apply a resistor material made of the bulk particles and glass, for example, by silk screen printing or the like, a vehicle is mixed with the resistor material powder to prepare a coating liquid. This vehicle is preferably one that can be burned out in the pre-firing stage.For this purpose, the resin is dissolved or dispersed in an organic vehicle, that is, an organic solvent, and various additives such as plasticizers and dispersants are added as necessary. Examples of the organic solvent, which is preferably added, include butyl carbitol acetate, butyl carbitol, turpentine oil, etc., and examples of the resin include cellulose derivatives such as ethyl cellulose and nitrocellulose, and other resins.

The usage ratio of this organic vehicle and the resistor material powder varies depending on the organic solvent, resin, etc. used, but the usage ratio of the organic solvent and resin is 20 to 50% by weight for the former and 80% for the latter.
~50% by weight is suitable. These components are made into a paste using a mixing means such as a three-roll mill or a sieve.

The resistor material paste obtained in this way is applied to a substrate, which is further processed as described below to create a resistor. In addition to a method in which a ceramic green sheet is fired in advance, a resistor material and a conductor material are further applied thereto, and then fired. These can also be applied when forming a laminate.

As the ceramic green sheet, for example, aluminum oxide (A It z (h) 35 to 45 IC amount %,
Silicon oxide (Sing) 25-35% heavy weight, boron (I)
hOz) 10-15% by weight, calcium oxide (Cab
) 7-13% by weight, magnesium oxide (MgO) 7
~10! For example, a slurry prepared by mixing a mixture of oxides of ceramic constituents with an organic vehicle in a ball mill or the like and forming the slurry into a sheet using a doctor blade or the like may be used. In this case, when glass is not used in combination with the mediocre molybdate of the element group, the ceramic green sheet may contain a large amount of glass to produce the same effect as when glass is used in combination. It is composed of acrylic resins such as acrylic acid esters, resins such as polyvinyl butyral, plasticizers such as glycerin and diethyl phthalate, dispersants such as carboxylic acid salts, and solvents such as water and organic solvents.

The resistor material paste is applied to a ceramic green sheet by means such as silk screen printing,
After drying, it is preferable that the resin component is decomposed and burned by heat treatment at 400 to 500°C.

At this time, a paste of a base metal conductor material such as Ni or Cu or a noble metal conductor material such as Ag or Ag-Pd is also applied to the ceramic green sheet in the same way as the resistor material paste coating film, and the paste is also applied to the ceramic green sheet in the same way as the resistor material paste coating. will be processed.

This base metal conductor material such as Ni or Cu or Ag
Alternatively, a paste composition of Ag-Pd noble metal conductor material is exemplified by adding 2 to 15 weight % of glass flift to 98 to 85 weight % of each metal powder.

In this way, the resistor material and/or conductor material is incorporated into the ceramic green sheet, but in the case of a fixed chip resistor, only the surface of this unfired substrate is incorporated, and in the case of a thick film resistor of a multilayer substrate, the resistor material and/or the conductor material are incorporated into the ceramic green sheet. The body material and conductor material assembled in an unfired state are further laminated to form a predetermined circuit, and then fired. By this firing, the conductor material and/or the thick film resistor material can be made into a fired body at the same time as the substrate.

In this case, when a base metal conductor material such as Ni or Cu is used as the conductor material, it is preferable to sinter it in a non-oxidizing atmosphere in order to prevent the resistance value from increasing due to oxidation, and the sintering temperature is as follows: For example, 800℃~1100℃
, 0.5 hours to 2 hours. As the non-oxidizing atmosphere, nitrogen gas, other active gases, and mixed gases containing these gases and hydrogen gas may also be used. Also, Ag or A
, -Pd can be fired in an oxidizing atmosphere such as air.

A circuit wiring board incorporating a conductor and/or a resistor is completed as described above, but there may be cracks, distortions, etc. not only between the fired board and the conductor but also between the fired board and the resistor due to firing. In addition to not causing any blistering, the resistance value of the resistor changes by ±0.1% or less against a relative humidity change of 10 to 90% at 25℃, and can be left in a high temperature and high humidity atmosphere for more than 1000 hours. However, the resistance value is suppressed to change within ±2%. This is thought to be due to the resistor's good matching with the conductor and fired substrate, and the unique moisture resistance of the resistor, which is made of a molybdate of an element from the above element group and a fired glass body, but the details are not clear. .

Incidentally, molybdate of the element used in the resistor can be recognized by XwA diffraction analysis. Furthermore, lumpy particles and needle-like particles can be observed using a transmission electron microscope.

In the present invention, molybdates of the elements selected as described above may be used, but instead of these molybdates, some or all of the precursors that become these molybdates by heat treatment can also be used. . In any of these cases, it is preferable to mix the bulk particles of the molybdate with glass, heat treat it, and then pulverize it to make a resistor material. It is also possible to directly create a resistor by applying the created paste onto a green ceramic sheet, for example, and then firing it through a heat treatment to remove organic matter.

Additionally, the glass may be placed in a state where the mixed material of the oxides constituting it is eventually fired together with the molybdates of the selected elements, and the precursors of these oxides are combined with the molybdates of the selected elements. A part or all of this oxide together with salt and/or its precursor is made into a paste state as described above, and this is applied to a substrate and the above glass components are removed by burning the organic material and then firing. Any material that can be used as long as it becomes a glass that can produce a resistor by firing it with a molybdate of the selected element and/or its precursor.For example, CaO (calcium oxide ) is heating CaC0+ (calcium carbonate), Btu3 (boron oxide) is heating boric acid (H
gBO*), so CaO, Btus
CaCOx, II instead of some or all of
JOs can be used. The resistor material in the present invention is selected as a result of the processing process 7:,! Any material whose main components are molybdate and glass may be used.

In the above example, molybdate or the like is used as the resistor material, but in order to reduce the temperature change coefficient of the resistance value of the electrical resistor, fluorides such as alkaline earth metals may also be used in combination. Carbonates such as alkaline earth metals may be used in combination with the paint.

Example Next, the present invention will be explained in detail.

Each component was weighed and mixed to have the composition shown in Table 1 in terms of oxide.

Table 1 In the table, the unit is weight%.

Each of the mixtures of Glass A and Glass B was separately melted in an alumina crucible at 1400°C, and the melt was poured into water and rapidly cooled. Take out this quenched material, put it in a bot mill with ethanol, and use an alumina ball for 24 hours.
The glass powder was pulverized for a period of time to obtain a glass powder with a particle size of 10 μm or less.

Example 1 Molybdenum oxide and magnesium carbonate were mixed at a molar ratio of 1, and heat treated at 700° C. for 1 hour to obtain a magnesium molybdate.

Next, Glass A obtained above and magnesium molybdate were mixed in the following composition.

MgMo0t 30 parts by weight Glass A 70 parts by weight
uz) 1000℃ in a 1.5 VO1% gas atmosphere,
The resultant was heat-treated for 1 hour, then ground with ethanol in a pot mill, and dried to obtain a resistor material of heat-treated powder of glass and magnesium molybdate having a size of 10 μm or less.

Next, 25 parts by weight of an organic vehicle (1 part by weight of butyl carbitol 90 parts, 10 parts by weight of ethyl cellulose) was added to 100 parts by weight of the above resistor material powder, and mixed in a roll mill.
A resistor material paste was obtained.

On the other hand, Al zoz 40.0% by weight, 5iOz35
．． 0% by weight, BZOff 13.0% by weight, CaO7.0
% by weight, 100 parts by weight of ceramic raw powder consisting of 05.0% by weight of Mg, 8 parts by weight of polyvinylbutytenyl, 8 parts by weight of diethyl phthalate, 0.5 parts by weight of oleic acid, 103 tt parts of acetone, and 20 parts by weight of isopropyl alcohol. and 20 parts by weight of methyl ethyl ketone were added and mixed in a ball mill to prepare a slurry, and after defoaming treatment, a long ceramic green sheet with a thickness of 200 μm was prepared using a doctor blade method. From this ceramic green sheet, a green sheet piece with length 9x and width 9M and length 6
I cut out 9 pieces of Tsuruyoko green sheet.

Next, as shown in FIG. 1, 95 parts by weight of copper powder, 5 parts by weight of glass lift, and 2 parts of butyl calpitol as an organic vehicle were placed on the above-mentioned green sheet piece l of 9 by 9 fi.
A conductive material paste obtained by adding 0 parts by weight and 5 parts by weight of ethyl cellulose and mixing them using a three-roll mill was silk screen printed and dried at 125° C. for 10 minutes to form a conductive material coating film 2. The resulting resistor material paste was silk screen printed on the green sheet piece 1 in the same manner as described above, and dried at 125° C. for 10 minutes to form a thick film resistor coating 3.

Next, the green sheet piece 4 of 6 fl length and 9 width width obtained above is stacked on top of the green sheet piece L as shown by the chain line in the figure.
00℃, thermocompression bonded at 150Kg/cj. Next, this is heated at 400 to 500℃ in an oxidizing atmosphere such as air to form green sheet pieces 1, 4, conductor material coating 2, and resistor material coating 3. Decompose and burn each residual organic matter.

After removing organic matter in this way, 98.5 vol of NO
950 in a mixed gas of 1%, Ht 1.5 vol.
℃ for 1 hour, and as shown in FIG. A multilayer ceramic substrate having a thick film resistor 3a as a fired body of a film conductor 2a and a resistor material coating film 3 was completed. In this multilayer ceramic substrate, no warping or blistering as shown in FIGS. 4 and 5, which will be described later, was observed.

The multilayer ceramic substrate of the fired body thus obtained was polished in the layer direction to expose the resistor layer, and the exposed resistor layer was analyzed by X-ray diffraction (Cu Kα ray). The results obtained are shown in FIG. In addition, Figure 7 shows a photograph taken using a transmission electron microscope, which shows the acicular particles, the magnesium molybdate in the darkly shaded area on the left, and the glass in the lightly shaded area on the right. ing. This sample for transmission electron microscopy was prepared by cutting a multilayer ceramic substrate with a thick film resistor into strips with a width of 200 μI in the cross-sectional direction, polishing them to a thickness of about 20 μI, and then cutting them using an ion milling device. It was made into thin sections.

Next, the resistance value (Ris) of this multilayer ceramic substrate 3a at 25°C and the resistance value (R
ags) was measured using a digital multimeter, and the temperature coefficient of resistance (TCR) was determined using the following equation.

The measured resistance value of R□ above is 1B, 5 x 10'Ω, T
The calculated value of CR was -831 ppa+/'C.

In addition, the multilayer ceramic substrate obtained above was heated at 60°C for 9
25℃ after 1000 hours under 5% relative humidity
The resistance value was measured and the rate of change was found to be within ±2%.

Example 2 Example 1 MgMo0. MgzMo instead of
A multilayer ceramic substrate was prepared in the same manner except that glass B was used instead of glass A, and measured and calculated values were obtained for the same items as in Example 1. ”=12.9X10”Ω,
The rate of change in TCR--744ppta/'C1Rts is ±
It was within 2%.・ Also, although not shown in the figure, MggMO
sOt 1 was confirmed, and lumpy particles, acicular particles, and glass were confirmed from the transmission micrograph.

Comparative Example 1 (Most, -TaSiz glass resistor material) A mixture of 16 parts by weight of MoSiz and 9 parts by weight of Tacit was heated at 1400°C in vacuum, and the product was ground with ethanol in an alumina ball in a pot mill for 24 hours. , and dried to obtain a fine powder of less than 10μ steel. For 25 parts by weight of the fine powder thus obtained, Ba02B2
01. 75 parts by weight of a glass lift consisting of MgO, CaO, and SiO2 and 25 parts by weight of an organic vehicle (20 parts by weight of butyl calpitol, 5 parts by weight of ethyl cellulose) were added and mixed in a roll mill to obtain a resistor material paste. Ta.

A multilayer ceramic substrate was obtained in the same manner as in the example except that this resistor material paste was used.

As a result, the ceramic green sheet was coated with a resistor material coating, heat-treated to remove organic matter, and then fired simultaneously. As shown in Figure 3, warpage is observed,
In addition, SiO□ is produced by the decomposition reaction of Mo5iz and Ta5iz.
Due to the generation of gas, blistering occurred as shown in FIG. 4, making it impossible to put it to practical use. In addition, lla
The ceramic layers 1a and 14a are the ceramic layers N4a and 13a are the thick film resistors corresponding to the thick film resistor 3a, respectively.

Comparative Example 2 (MoSix-11aFz glass resistor material) MoSit 7O1i parts, BaFz 20 weight parts, Sing, ZnO, Zr0z, CaO1AI! gos
The resulting powder was mixed with 10 parts by weight of glass lift consisting of
After heat-treating at 200°C, this was pulverized with ethanol using an alumina ball in a pot mill for 24 hours, and dried to obtain a fine powder of 10 μm or less.

A multilayer ceramic substrate was obtained in the same manner as in Example 1 except that this resistor material paste was used. For the thick film resistor of this multilayer ceramic substrate, R, , , TCP and the rate of change in resistance value obtained in the same manner as in Example 1' are shown in Table 2.

Table 2 From the above results, the multilayer ceramic substrates of Examples have no warping or blistering, and the rate of change in resistance value is within ±2%, whereas the multilayer ceramic substrate of Comparative Example 1 has warpage. It can be seen that the multilayer ceramic substrate of Comparative Example 2 has a rate of change in resistance value that is four times larger.

Effects of the Invention According to the present invention, it is possible to provide an electrical resistor having a fired body in which acicular particles are attached to or in close proximity to lump particles. When a resistor is formed by firing a base metal conductor material together with a ceramic green sheet in a non-oxidizing atmosphere, acicular particles can be grown from the surface of the lump particles. In addition, the fired product does not warp or bulge during firing, and
Changes in the resistor over time, especially under high humidity conditions, can be reduced.

This satisfies the demands for both miniaturization and cost reduction of a circuit board incorporating a resistor, and contributes to further improvement in the performance of the circuit board.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the structure of the electrical resistor of the present invention, and FIG. 2 is a diagram showing the formation of a resistor material coating film and a conductive material coating film on a substrate before firing when manufacturing the electrical resistor of the present invention, Figure 3 is a cross-sectional view of the fired body, and Figure 4 is a cross-sectional view of the fired body when a multilayer structure is formed using conventional resistor material. Fig. 5 is an explanatory diagram showing a state in which gas is further generated in the fired body, Fig. 6 is an X-ray diffraction diagram when molybdate of gnesium is detected in the electrical resistor of Example 1 of the present invention, and Fig. 7 is an explanatory diagram showing a state in which gas is generated in the fired body. The figure is a transmission micrograph showing the structure of this electrical resistor. In the figure, a is glass, b is lumpy particles, C is needle-like particles, 1,
4 is a green sheet piece, 2 is a conductor material coating, 3 is a resistor material coating, 1a, 4a are ceramic layers, 2a is a thick film conductor, 3a
is a thick film resistor. April 30, 1985

Claims (5)

[Claims] (1) An electrical resistor characterized by having a fired body containing lumpy particles, acicular particles attached to or in the vicinity of the lumpy particles, and a glass layer. (2) The electrical resistor according to claim 1, wherein the lumpy particles and the acicular particles attached to or in the vicinity of the lumpy particles are electrically conductive particles. . (3) The lumpy particles contain at least one type of molybdate selected from the following groups (A) to (G), and the acicular particles contain a reduction product of the molybdate. The electrical resistor according to claim 1, characterized in that it contains: (A) Alkaline earth metal molybdate (B) Zinc molybdate (C) Y, La, Ce, Pr, Nd, Sm, Eu, Gd
, Tb, Dy, Ho, Er, Tm, Yb, Lu, and composite molybdates of multiple elements among these elements (D) Molybdates of aluminum (E) Zirconium, hafnium molybdates Molybdates of each element and their composite molybdates (F) Molybdates of each element of niobium and tantalum and their composite molybdates (G) Molybdates of manganese (4) The bulk particles and acicular particles are fired from a resistor material containing as a main component at least one of molybdates and their precursors corresponding to groups (A) to (G). An electrical resistor according to claim 1. (5) The bulk particles containing the resistor body material constituting the electrical resistor body are fired in a non-oxidizing atmosphere, the surface of the bulk particles is reduced, and the reduction product of the acicular particles is attached to the bulk particles. Or, a method for manufacturing an electrical resistor, comprising the step of making the bulk particles exist near the lump particles.