JP2022076098A - Ceramic wiring board and method for manufacturing ceramic wiring board - Google Patents

Abstract

To suppress deterioration in withstand voltage characteristics of a resistor in a ceramic wiring board.SOLUTION: In a ceramic wiring board, a resistor containing a conductive material and a second glass is formed in a ceramic substrate containing a first glass. The composition of the first glass in the ceramic substrate and the composition of the second glass in the resistor are different from each other. The softening point Tsa of the first glass and the crystallization temperature Tcb of the second glass satisfy the following inequality (1): Tsa>Tcb.SELECTED DRAWING: Figure 1

Description

The present invention relates to a ceramic wiring board and a method for manufacturing a ceramic wiring board.

A multilayer glass ceramic substrate with a built-in resistor (hereinafter also referred to as "ceramic wiring substrate") having an insulating layer made of glass ceramics, an internal conductor formed between the insulating layers, and a resistor connected to the internal conductor is known. (See, for example, Patent Document 1). In the ceramic wiring substrate described in Patent Document 1, the glass softening point of the glass powder contained in the resistor is equal to or higher than the temperature obtained by subtracting 110 ° C. from the glass softening point of the glass powder used for the insulating layer, and the insulating layer has a glass softening point. The temperature is equal to or lower than the temperature obtained by adding 70 ° C. from the glass softening point of the glass powder used.

Japanese Patent No. 6113664

Here, in the case of manufacturing a ceramic wiring board having a resistor built in between insulating layers, generally, a green sheet for forming an insulating layer and a resistor are fired at the same time. In this case, the glass contained in the green sheet and the glass contained in the resistor may be mixed with each other. When these glasses are mixed, the amount of glass inside the resistor changes due to changes in time and temperature under firing conditions, which may affect the characteristics of the resistor, mainly the withstand voltage characteristics. Therefore, there has been a demand for suppressing the deterioration of the characteristics of such a resistor. In this regard, the "glass softening point" considered in the technique described in Patent Document 1 refers to the timing at which the glass begins to flow, and the glass contained in the green sheet and the glass have only this glass softening point. It is not easy to suppress mixing with the glass contained in the resistor.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to suppress deterioration of the withstand voltage characteristics of a resistor in a ceramic wiring board.

The present invention has been made to solve the above-mentioned problems, and can be realized as the following forms.

(1) According to one embodiment of the present invention, there is provided a ceramic wiring board in which a resistor containing a conductive material and a second glass is formed on a ceramic substrate containing the first glass. In this ceramic wiring substrate, the structure of the first glass in the ceramic substrate and the structure of the second glass in the resistor are different, and further, the softening point Tsa of the first glass and the second glass The crystallization temperature Tcb satisfies the following formula (1).
Tsa> Tcb ... (1)

During the manufacture of the ceramic wiring board having this configuration, the component of the second glass contained in the resistor reaches the crystallization temperature Tcb before the component of the first glass contained in the ceramic substrate reaches the softening point Tsa. As a result, even if the firing time of the ceramic wiring board is long, the component of the second glass contained in the resistor is crystallized before the component of the first glass contained in the ceramic substrate is softened. Therefore, it is possible to prevent the component of the first glass contained in the ceramic substrate from being mixed with the component of the second glass contained in the resistor. As a result, the variation in the resistance value of the resistor due to the length of the firing time is suppressed, and a dense resistor can be obtained, so that the characteristics of the resistor do not deteriorate.

(2) In the ceramic wiring board of the above aspect, the first glass may contain diopside.
According to this configuration, the ceramic substrate is resistant to sudden temperature changes.

(3) In the ceramic wiring board of the above aspect, the resistor may be built in the board.
According to this configuration, since the resistor is built in the ceramic substrate, the amount of the resistor mounted on the surface of the ceramic substrate can be reduced.

The present invention can be realized in various aspects, for example, in the form of a ceramic wiring board, a wiring board with a built-in resistor material, a wiring board, a method for manufacturing a ceramic wiring board, and a system including these. It can be realized.

It is a schematic sectional drawing of the composite laminated sintered body provided with the ceramic wiring board of embodiment of this invention. It is a flowchart of the manufacturing method of the composite laminated sintered body provided with a ceramic wiring board. It is a schematic sectional drawing of a primary laminated body. It is a schematic sectional drawing of the 1st green sheet in which a through hole was formed. It is the schematic sectional drawing of the composite sheet laminated body before being laminated. It is explanatory drawing about the evaluation of the ceramic wiring board of an Example and a comparative example.

<Embodiment>
Configuration of Ceramic Wiring Board FIG. 1 is a schematic cross-sectional view of a composite laminated sintered body 100 including the ceramic wiring board 10 of the embodiment of the present invention. The composite laminated sintered body 100 is a sintered body in which a plurality of layers mainly composed of ceramics are laminated in the thickness direction. As shown in FIG. 1, the composite laminated sintered body 100 of the present embodiment includes a single-layer ceramic wiring board 10 and outer ceramic substrates 20 and 30 laminated on both sides of the ceramic wiring board 10. There is.

The ceramic wiring board 10 of the present embodiment is a low temperature co-fired ceramics substrate (LTCC) containing glass. The ceramic wiring board 10 is a substrate on which inner ceramic substrates (ceramic substrates) 1 and 2 containing ceramic and glass are formed with a resistor 3 containing RuO ₂ which is a powder of a conductive material and glass. Hereinafter, the glass contained in the inner ceramic substrates 1 and 2 will be referred to as a first glass GL1, and the glass contained in the resistor 3 will be referred to as a second glass GL2.

As shown in FIG. 1, the ceramic wiring board 10 is formed between an inner ceramic substrate 1 and 2 laminated in the thickness direction (Z-axis direction) and an inner layer electrode 1 and 2 formed between the two inner ceramic substrates 1 and 2. It includes 4, 5 and a resistor 3 formed so as to be in contact with a part of the inner layer electrodes 4, 5. The inner ceramic substrates 1 and 2 of the present embodiment are formed of borosilicate glass containing SiO ₂ , CaO, BaO, MgO, etc. as the first glass GL 1 and Al ₂ O ₃ (alumina) as the ceramic. ing.

The inner ceramic substrates 1 and 2 are crystallized and contain diopside. The softening point Tsa of the first glass GL1 of the present embodiment is 863 degrees Celsius (° C.). The softening point Tsa of the first glass GL1 is controlled by the ratio of SiO ₂ and the like contained in the first glass GL1.

The inner layer electrodes 4 and 5 are formed of Ag and borosilicate glass. As shown in FIG. 1, the resistor 3 of the present embodiment is built in the inner ceramic substrate 2. The resistor 3 is formed of RuO ₂ as a component of the second glass GL 2 and borosilicate glass as the second glass GL 2. The crystallization temperature Tcb of the second glass GL2 of the present embodiment is 790 ° C. In this embodiment, the ratio of SiO _{2 and the like contained in the first glass GL 1 and the ratio of SiO 2 and} the like contained in the second glass GL 2 are different. That is, the composition of the first glass GL1 and the composition of the second glass GL2 are different.

As shown above, the relationship of the following (1) is between the first glass GL1 softening point Tsa of the inner ceramic substrates 1 and 2 and the second glass GL2 crystallization temperature Tcb of the resistor 3 in the present embodiment. be satisfied.
Tsa> Tcb ... (1)

As shown in FIG. 1, the outer ceramic substrates 20 and 30 are laminated on the outer surfaces of the inner ceramic substrates 1 and 2 of the ceramic wiring board 10. The outer ceramic substrates 20 and 30 are formed mainly of Al ₂ O ₃ (alumina), which is a ceramic.

-Method of manufacturing a composite laminated sintered body including a ceramic wiring board FIG. 2 is a flowchart of a method of manufacturing a composite laminated sintered body 100 including a ceramic wiring board 10. In the manufacturing flow of the composite laminated sintered body 100 shown in FIG. 2, first, the materials of the inner ceramic substrates 1 and 2, the outer ceramic substrates 20 and 30, the inner layer electrodes 4 and 5, and the resistor 3 are prepared. (Step S1).

As the material of the first green sheet of the inner ceramic substrates 1 and 2 before sintering, borosilicate glass powder containing SiO ₂ , CaO, BaO, MgO, etc. having an average particle size of 2.0 μm, and an average particle size of 2. 5 μm of Al ₂ O ₃ (alumina) is prepared. Al ₂ O ₃ (alumina) having an average particle size of 2.5 μm is prepared as a material for the second green sheet of the outer ceramic substrates 20 and 30 before sintering. As the material of the inner layer electrode paste of the inner layer electrodes 4 and 5 before sintering, Ag powder having an average particle size of 2.0 μm and glass powder having an average particle size of 2.0 μm are prepared. RuO ₂ powder and glass powder are prepared as materials for the resistor paste of the resistor 3 before sintering. In the glass powder prepared as each material, the amount and the ratio of the components contained in the glass powder are appropriately selected in order to control the composition of each member after sintering.

Next, a slurry and a paste material are produced by adding a binder and a solvent to the prepared materials of each member and stirring the mixture (step S2). The slurry of the first green sheet is a total amount of 800 g of a mixture of borosilicate glass powder and alumina powder at a mass ratio of 3: 2, 80 g of an acrylic binder as a binder component, and MEK (methyl ethyl ketone) and toluene as solvents. And DOP (the octyl phthalate) as a plasticizer are mixed and produced. When this mixture is put into a pot made of alumina and mixed for 5 hours, a ceramic slurry is obtained. The amount of the solvent and the plasticizer added to the mixture is selected to be the amount required to have the slurry viscosity and the sheet strength.

The slurry of the second green sheet is prepared by mixing 1000 g of alumina powder with 120 g of an acrylic binder, MEK and toluene as a solvent, and DOP as a plasticizer. When this mixture is placed in an alumina pot and mixed for 3 hours, a slurry is obtained.

The inner layer electrode paste is prepared by adding ethyl cellulose resin as a varnish component and butyl carbitol solvent to a mixed powder in which Ag powder and glass powder are mixed at a volume ratio of 80:20. When this mixture is kneaded by a three-roll mill, an inner layer electrode paste is produced.

The resistor paste is a mixed powder obtained by mixing RuO ₂ powder and glass powder at a volume ratio of 80:20, ethyl cellulose resin (2 to 8 wt%) as a varnish component, and butyl carbitol solvent (25 to 35 wt%). And an additive (0 to 3 wt%) are added to prepare the product. When this mixture is kneaded by a three-roll mill, a resistor paste is produced.

Next, the produced first green sheet and the slurry that is the source of the second green sheet are formed into a film (step S3). The slurry that is the source of the first green sheet is formed into a film having a thickness of 0.20 mm by the doctor blade method. The slurry that is the source of the second green sheet is formed into a film having a thickness of 0.50 mm by the doctor blade method.

After the film formation, the first green sheet and the second green sheet cut to a predetermined size are produced (step S4). An inner layer electrode paste as an electrode pattern for an inner conductor for connection is formed on the surface of the produced first green sheet by printing (step S5). After the first green sheet on which the inner layer electrode paste is printed is dried, a resistor paste is formed by printing at a predetermined position on the first green sheet (step S6), and the primary laminate 11 is produced.

FIG. 3 is a schematic cross-sectional view of the primary laminated body 11. As shown in FIG. 3, the inner layer electrode pastes P4 and P5 are printed on the surface of the first green sheet (green sheet) SH1, and then the resistor paste P3 is printed. The resistor paste P3 of the present embodiment is printed by a printing pattern of 1.0 mm × 1.2 mm so as to overlap with the electrode pattern for the internal conductor.

A through hole of φ1.0 mm is formed by microcomputer punching in the first green sheet different from the first green sheet SH1 on which the inner layer electrode pastes P4 and P5 and the resistor paste P3 are printed. (Step S7 in FIG. 2).

FIG. 4 is a schematic cross-sectional view of the first green sheet (green sheet) SH2 in which the through hole H1 is formed. In FIG. 4, in addition to the first green sheet SH2 in which the through hole H1 is formed, the primary laminate 11 to be laminated later on the first green sheet SH2 is also shown. The through hole H1 is formed between the two first green sheets SH1 and SH2 when the primary laminated body 11 and the first green sheet SH2 on which the through hole H1 is formed are laminated. It is a hole to make it connectable to.

The second green sheet is laminated on both sides of the multilayer body in which the primary laminate 11 and the first green sheet SH2 in which the through hole H1 is formed are laminated to produce a composite sheet laminate as shown in FIG. (Step S8 in FIG. 2).

FIG. 5 is a schematic cross-sectional view of the composite sheet laminated body before being laminated. As shown in FIG. 5, the primary laminated body 11, the first green sheet SH2 arranged on the upper side of the primary laminated body 11, and the second green sheet SH30 arranged on the upper side of the first green sheet SH2 are primary. A composite sheet laminated body is produced by laminating the second green sheet SH20 arranged under the laminated body 11.

The produced composite sheet laminate is fired at 900 ° C. for 1 hour (1 h) (step S9 in FIG. 2) to produce the composite laminated sintered body 100. In the firing step, the first green sheets SH1 and SH2 and the resistor paste P3 are fired at the same time. When the composite laminated sintered body 100 is generated, the manufacturing flow of the composite laminated sintered body 100 is completed.

-Evaluation of Ceramic Wiring Board FIG. 6 is an explanatory diagram for evaluation of ceramic wiring boards of Examples and Comparative Examples. FIG. 6 shows ESD (Electro-Statics) of the example as the ceramic wiring board 10 of the above embodiment and the wiring board of the comparative example in which the crystallization temperature Tcb was changed by adjusting the composition of the second glass GL2. Discharge) The evaluation result of the characteristic value (%) is shown. In the evaluation of the present embodiment, the variation between the ESD characteristics when firing at 900 ° C. for 1 hour and the ESD characteristics when firing at 900 ° C. for 3 hours (3 hours) in the firing step of the production method of FIG. 2 is evaluated. rice field. An ESS-100L device manufactured by Noise Research Institute was used for measuring the ESD characteristics. In the measurement, a voltage of 2 kV was applied in 5 pulses, the resistance value before and after the application of the voltage was measured, and the rate of change of the measured value was taken as the ESD characteristic value. The glass composition shown in FIG. 6 is an element contained in the second glass GL2 of Examples and Comparative Examples.

Examples and Comparative Examples are samples in which the crystallization temperature Tcb was changed by controlling the glass composition using the method for manufacturing the ceramic wiring board 10 of FIG. The sample of the example is prepared so that the crystallization temperature Tcb of the second glass GL2 is smaller than the softening point Tsa of the first glass GL1. The sample of the comparative example is prepared so that the crystallization temperature Tcb of the second glass GL2 is higher than the softening point Tsa of the first glass GL1. The crystallization temperature Tcb of each sample and the softening point Tsa of the first glass GL1 were measured by differential thermal analysis (DTA). The differential thermal analysis was carried out under the condition that a Pt pan (φ5 mm × 5 mmt) was filled with 40 mg of a glass sample of each sample and the temperature was raised to 1000 ° C. in the air at a heating rate of 5 ° C./min. In the curve obtained by the differential thermal analysis, the endothermic peak temperature of the second endothermic part was measured as "softening point Tsa", and the peak temperature of the endothermic part developed at a temperature higher than the second endothermic peak was measured as "crystallization temperature Tcb". ..

For example, as shown in FIG. 6, the crystallization temperature Tcb of the example is 790 ° C., which is lower than the softening point Tsa of the first glass GL1 of 863 ° C. On the other hand, the crystallization temperature Tcb of the comparative example is 914 ° C, which is higher than the softening point Tsa of the first glass GL1 of 863 ° C.

As shown in FIG. 6, in the ceramic wiring substrate 10 including the second glass GL2 of the embodiment, the measured value of any ESD characteristic is 0.0 regardless of the firing time. That is, the ESD characteristics of the examples are not affected by the firing time, and the variation in the measured values is small. On the other hand, the measured value of the ESD characteristic of the ceramic wiring substrate including the second glass GL2 of the comparative example is -7.2 when the firing time is 1h, and -1 when the firing time is 3 hours. It is 3. That is, the ESD characteristics of the comparative example are affected by the firing time, and the measured values vary widely.

As described above, in the ceramic wiring board 10 of the present embodiment, the composition of the first glass GL1 contained in the inner ceramic substrates 1 and 2 is different from the composition of the second glass GL2 contained in the resistor 3. Further, as shown in FIG. 6, the softening point Tsa of the first glass GL1 and the crystallization temperature Tcb of the example satisfy the magnitude relationship of Tsa> Tcb represented by the above formula (1). .. Therefore, at the time of manufacturing the ceramic wiring board 10 of the present embodiment, the component of the second glass GL2 contained in the resistor 3 is contained before the component of the first glass GL1 contained in the inner ceramic substrates 1 and 2 reaches the softening point Tsa. Reachs the crystallization temperature Tcb. As a result, even if the firing time of the ceramic wiring board 10 becomes long, the component of the second glass GL2 contained in the resistor 3 is released before the component of the first glass GL1 contained in the inner ceramic substrates 1 and 2 softens. Crystallize. Therefore, it is possible to prevent the component of the first glass GL1 contained in the inner ceramic substrates 1 and 2 from being mixed with the component of the second glass GL2 contained in the resistor 3. As a result, the variation in the resistance value of the resistor 3 due to the length of the firing time is suppressed, and the dense resistor 3 can be obtained, so that the characteristics of the resistor 3 do not deteriorate.

Further, the first glass GL1 included in the inner ceramic substrates 1 and 2 of the present embodiment contains diopside. Therefore, the inner ceramic substrates 1 and 2 of the present embodiment have resistance to sudden temperature changes.

Further, as shown in FIG. 1, the resistor 3 of the present embodiment is built in the inner ceramic substrate 2. Therefore, the amount of the resistor mounted on the surface of the inner ceramic substrate 2 can be reduced.

<Modified example of this embodiment>
The present invention is not limited to the above embodiment, and can be carried out in various embodiments without departing from the gist thereof, and for example, the following modifications are also possible.

The above-described embodiments and examples are examples of the ceramic wiring board 10, and the configurations and components of the ceramic wiring board 10 can be variously modified. For example, the glass composition of the first glass GL1 can be changed within a range satisfying the relationship of the above formula (1), and may not contain, for example, Mg or the like, and is different from the same element as the first glass GL1. It may be included in an amount. Further, the ceramic wiring board 10 does not have to include diopside.

In the composite laminated sintered body 100 of another embodiment, a plurality of ceramic wiring boards may be laminated. For example, it may be a composite laminated sintered body in which both sides of the laminated body in which the plurality of ceramic wiring boards 10 of the above embodiment are laminated are sandwiched between the second green sheets SH20 and SH30. The conductive material contained in the resistor 3 may be other than RuO ₂ , and a powder having well-known conductivity can be adopted.

Although this embodiment has been described above based on the embodiments and modifications, the embodiments described above are for facilitating the understanding of the present embodiment and do not limit the present embodiment. This aspect may be modified or improved without departing from its spirit and claims, and this aspect includes its equivalent. Further, if the technical feature is not described as essential in the present specification, it may be deleted as appropriate.

1, 2, ... Inner ceramic substrate (ceramic substrate)
3 ... Resistor 4 ... Inner layer electrode 10 ... Ceramic wiring board 11 ... Primary laminate 20, 30 ... Outer ceramic substrate 100 ... Composite laminated sintered body GL1 ... First glass GL2 ... Second glass H1 ... Through hole P3 ... Resistor Paste P4 ... Inner layer electrode paste SH1, SH2 ... First green sheet (green sheet)
SH20, SH30 ... 2nd green sheet Tcb ... Crystallization temperature of 2nd glass GL2 Tsa ... Softening point of 1st glass GL1

Claims (4)

In a ceramic wiring board in which a resistor containing a conductive material and a second glass is formed on a ceramic substrate containing the first glass.
The composition of the first glass in the ceramic substrate is different from the composition of the second glass in the resistor.
Further, a ceramic wiring board characterized in that the softening point Tsa of the first glass and the crystallization temperature Tcb of the second glass satisfy the following formula (1).
Tsa> Tcb ... (1) In the ceramic wiring board according to claim 1,
The first glass is a ceramic wiring board, characterized in that it contains diopside. In the ceramic wiring board according to claim 1 or 2.
The resistor is a ceramic wiring board, characterized in that it is built in the ceramic board. A resistor pattern is formed on the surface of the green sheet containing the ceramic and the first glass using a resistor paste containing the conductive material and the second glass, and the green sheet and the resistor pattern are simultaneously fired. In the method of manufacturing a ceramic wiring board for manufacturing a ceramic wiring board provided with a resistor,
The structure of the first glass in the green sheet is different from the structure of the second glass in the resistor paste.
Further, a method for manufacturing a ceramic wiring substrate, wherein the softening point Tsa of the first glass and the crystallization temperature Tcb of the second glass satisfy the following formula (1).
Tsa> Tcb ... (1)

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