TWI648240B - Low dielectric constant dielectric porcelain powder composition which is ultra-low temperature sintered in a reducing atmosphere and Preparation method and temperature-compensated - Google Patents

Abstract

The invention relates to a dielectric porcelain powder composition for a low dielectric constant temperature compensating multilayer ceramic capacitor for ultra-low temperature sintering in a reducing atmosphere, and is particularly suitable for manufacturing a temperature coefficient of capacitance of 0±30ppm/°C (so-called NP0 specification). Or C0G specification) for laminated ceramic capacitors. The sintering temperature is below 1000 ° C, and it can be matched with the copper internal electrode and sintered under a reducing atmosphere to form a laminated ceramic capacitor. The present invention comprises 100 parts by weight of the first components a mole MgO, b mole CaO, c mole SiO ₂ , d mole ZrO ₂ and e mole TiO ₂ as shown below, and a+b=1, and 0.35≦a≦0.80, 0.20≦b≦0.65, 0.40≦c≦0.90, 0.05≦d≦0.35, 0.05≦e≦0.25, and 4-20 parts by weight of Li ₂ O, BaO, ZnO, SiO ₂ , and B a glass frit of a second component consisting of ₂ O ₃ , wherein the composition of the glass frit is 0% ≦ Li ₂ O ≦ 25%, 10% ≦ BaO ≦ 60%, 0% ≦ ZnO ≦ 30%, 5% ≦SiO ₂ ≦ 40%, 5% ≦B ₂ O ₃ ≦ 45%.

Description

Low dielectric constant dielectric porcelain powder composition which is ultra-low temperature sintered in a reducing atmosphere and Preparation method and temperature-compensated multilayer ceramic capacitor thereof

The invention relates to a low-k dielectric porcelain powder composition which is resistant to a low-temperature sintering in a reducing atmosphere and a preparation method thereof, and can be used for manufacturing a temperature-compensated multilayer ceramic capacitor. The invention is more suitable for use by the Electronic Industry Association (EIA), the temperature coefficient is NP0 or C0G specification, that is, the temperature coefficient of the capacitance value of the capacitor (1/C) (△C/△T ) must be in the range of 0 ± 30ppm / °C.

Generally, ceramic capacitors can be classified into three types according to the dielectric constant of the porcelain powder composition: high dielectric constant type (Hi-K), dielectric constant type (Mid-K) and temperature compensation type (TC). The high dielectric constant type has a dielectric constant of 4000 to 15000, but its value varies greatly with temperature. The dielectric constant of the dielectric constant type is about 1400 to 3000, and the dielectric constant changes little with temperature but is often nonlinear. The temperature-compensated dielectric constant is about 8 to 100, and the dielectric constant changes minimally with temperature and is often linear.

The internal electrode of the multilayer ceramic capacitor and the ceramic dielectric layer must be co-fired together. Therefore, the ceramic powder composition of the commercially available laminated ceramic capacitor can be roughly classified into a high temperature firing system and a low temperature firing system depending on the firing temperature. The firing temperature of the system is about 1250 ° C ~ 1300 ° C. Because of its high firing temperature, the internal electrode generally needs to use a palladium (Pd) noble metal with a high melting point and an expensive price. Since the low-temperature firing system has a firing temperature of 1150 ° C or less, the internal electrode can be reduced in cost and economical by using a silver-palladium alloy metal (Ag/Pd) which is inexpensive and has a high silver content.

In recent years, the mobile phone and communication markets have grown rapidly, and the demand for high-frequency components has increased dramatically. If the internal electrode is made of Cu, the cost is lower than that of silver-palladium alloy metal (Ag/Pd) and it has superior electrical conductivity, lower Equivalent Series Resistance (ESR) and Dissipation Factor (DF). ) is more suitable for making high frequency components.

Generally, the dielectric constant of the ceramic powder composition of the temperature-compensated capacitor is about 8 to 100. However, in the current technology, when manufacturing a low-capacitance NP0 multilayer ceramic capacitor of 10 pF or less, if the dielectric constant of the ceramic powder is high, the laminated layer is The number is small, often due to process control is not easy, the capacitance value of the ceramic capacitor often deviates from the specification value, so that the yield is low; therefore, the current production of multilayer ceramic capacitors below 10pF is often made of porcelain powder with a low dielectric constant of 20 or less. Seek to improve yield and optimize economic production.

Generally, low-temperature firing is a composition of dielectric porcelain powder, usually by using a high-temperature fired main component and adding various sintering aids such as glass, frit or flux. In order to lower the firing temperature, generally the glass or glass frit contains a low melting point component such as Pb or Cd or Bi. Pb and Cd are harmful substances to the environment and ecology. In response to the trend of environmental protection, it is necessary to develop a composition of dielectric porcelain powder containing no Pb or Cd.

In the process of the actual laminated ceramic capacitor, since the copper metal has a low melting point (~1050 ° C) and is easily oxidized into an insulator under high temperature air and loses the role of the electrode, it is not suitable for co-firing with the ceramic powder in the conventional atmospheric environment. However, it is necessary to co-fire in a reducing atmosphere such as N ₂ or N ₂ /H ₂ . Therefore, it is necessary to develop a low-k dielectric porcelain powder which can be sintered at a low temperature in a reducing atmosphere.

Regarding a low dielectric constant temperature compensating ceramic capacitor composition, a main component of MgO-CaO-TiO ₂ -Al ₂ O ₃ -SiO ₂ -Nb ₂ O ₅ and a subcomponent PbO-Bi are disclosed in U.S. Patent No. 4,506,026. The composition of ₂ O ₃ -CdO-ZnO-SiO _2- B ₂ O ₃ glass meets the requirements of EIA's NPO specification, and its dielectric constant is about 14-18, and the resulting capacitor has a dissipation factor (Dissipation Factor, Tan δ ) is 0.0002 or more, that is, the Q value (=1/tan δ ) is about 5,000 or less. A composition comprising a main component of MgO-ZnO-CaO-TiO ₂ and a by-component CdO-MgO-ZnO-B ₂ O ₃ -SiO ₂ flux disclosed in U.S. Patent No. 4,533,974, having a dielectric constant of about 20, but two The invention has a sintering temperature of more than 1100 ° C and is a titanic acid. The sintered ceramic body is easily semiconducting under a reducing atmosphere and the insulation resistance is lowered. Therefore, it must be sintered under an oxidizing atmosphere and thus cannot be used together with the copper internal electrode. burn.

Therefore, the Li ₂ O-BaO-ZnO-SiO ₂ -B ₂ O ₃ glass frit can be added in a reducing atmosphere and the firing temperature is below 1000 ° C, and MgO-CaO-SiO ₂ -ZrO ₂ -TiO ₂ as a main component. The low dielectric constant dielectric powder composition of the subcomponent containing no Pb, Cd, Bi and ultra-low temperature sintering in a reducing atmosphere has not appeared.

The invention selects a suitable main component system, and adds a sintering aid containing no Pb, Cd or Bi to lower the sintering temperature to below 1000 ° C, and can be sintered in a reducing atmosphere, and can be manufactured at a lower cost by using a cheaper copper internal electrode. Economical and electrically reliable multilayer ceramic capacitors.

The object of the present invention is to develop a laminated ceramic capacitor which can be sintered at a low temperature of 1000 ° C or less in a reducing atmosphere, and which does not contain lead, cadmium, tellurium and the like, and can be sintered under a reducing atmosphere and its electrical properties are introduced. The electric constant can be up to 18 or less, the Q value is above 1000, and the temperature coefficient is in accordance with the IA0 specification of EIA, that is, 0±30ppm/°C, which is suitable for the dielectric porcelain powder used for manufacturing the temperature compensation type multilayer ceramic capacitor.

In order to achieve the above object, the dielectric powder composition of the low dielectric constant laminated ceramic capacitor of the ultra-low temperature sintering resistance in the present invention has a molar ratio of 0.35 ≦MgO ≦ 0.80, 0.20 ≦ CaO per 100 parts by weight. ≦0.65, 0.40≦SiO ₂ ≦0.90, 0.05≦ZrO ₂ ≦0.35, 0.05≦TiO ₂ ≦0.25, and 4-20 parts by weight of Li ₂ O, BaO, SiO ₂ , ZnO and B ₂ O ₃ A two-component glass frit in which the composition of the glass frit is 0% ≦ Li ₂ O ≦ 25%, 10% ≦ BaO ≦ 60%, 5% ≦ SiO ₂ ≦ 40%, 0% ≦ ZnO ≦ 30%, 5% ≦ B ₂ O ₃ ≦ 45%.

According to the above composition range, CaMgSi ₂ O ₆ , Ca ₂ MgSi ₂ O ₇ , Ca ₂ Zr ₅ Ti ₂ O ₁₆ , CaTiO ₃ and the like are formed by calcination, and frit is added to reduce the sintering temperature to 1000 ° C. Hereinafter, the compactness of the sintered body is improved. Control the content ratio of different CaMgSi ₂ O ₆ , Ca ₂ MgSi ₂ O ₇ , Ca ₂ Zr ₅ Ti ₂ O ₁₆ , CaTiO ₃ phases, adjust the dielectric constant and capacitance temperature coefficient; add glass frit to improve sintering Density, increase insulation resistance.

To further reveal the technical content of this case, please refer to the following examples:

The dielectric porcelain powder composition of the present invention is Mg(OH) ₂ (magnesium hydroxide) or MgCO ₃ (magnesium carbonate), CaCO ₃ (calcium carbonate), SiO ₂ (yttria), ZrO ₂ (zirconia), TiO ₂ (titanium oxide) is used as a starting material, and is weighed according to the composition ratio shown in Table (1). It is wet-mixed in a ball mill for 16 hours, poured out and dried, and then simmered in a kiln at a temperature of 1050 ° C or higher. After 2 hours, the crucible was finely ground to 1.0 μm or less as the first component in the present invention.

The glass frit of the second component starts from zinc oxide (ZnO), barium carbonate (BaCO ₃ ), lithium carbonate (Li ₂ CO ₃ ), boric acid (H ₃ BO ₃ ), and cerium oxide (SiO ₂ ). The starting material is based on 0% ≦ Li ₂ O ≦ 25%, 10% ≦ BaO ≦ 60%, 5% ≦ SiO ₂ ≦ 40%, 0% ≦ ZnO ≦ 30%, 5% ≦ B ₂ O ₃ ≦ 45% 100% of the formula, according to the proportion of weighing, mixing, drying, melt water quenching at 1200 ° C and fine grinding to 1.5 μm or less.

Then, according to the weight ratio of Table (2), the frit of the first component main ingredient and the second component is weighed and mixed in a ball mill for 16 hours, and the final formula powder is obtained after drying. The formula powder was further added with a 20% solution containing 10% polyvinyl alcohol (PVA), granulated, and then pressed into a disk shape having a diameter of 10 mm and a thickness of 1.0 mm at a pressure of 1.5 Ton/cm ² . The embryonic sheet is coated on the two sides of the test piece by a screen printing method, and a copper paste is co-firing; in the co-firing treatment, A test piece of a dielectric ceramic composition coated with a copper metal paste is subjected to a degreasing reaction under a high purity nitrogen gas (99.999% N ₂ ) atmosphere of 600 ° C for 4 hours; and then, the temperature is further increased to a pure nitrogen gas of 1000 ° C or less. Or a nitrogen/hydrogen mixed atmosphere (a ratio of hydrogen to a mixed gas of 0 to 1.5%) is subjected to a sintering reaction for 2 hours. After the dielectric ceramic composition and the copper metal are co-sintered under a reducing atmosphere, the electrical properties and the sintered density are measured according to the following test conditions: the frequency is 1 MHz, the test voltage is 1 Vrms, the capacitance value is measured, and the dielectric constant ε and the measurement are calculated. DF value (ie, dissipation factor tan δ); with DC voltage of 500V, charging for 1 minute, temperature of 25 ° C, measuring resistance value; with 25 ° C capacitance value as reference, measuring the temperature coefficient of capacitance at 125 ° C, capacitance temperature coefficient by the following formula Calculation. Temperature coefficient (ppm/°C): [(C ₁₂₅ -C ₂₅ )/C ₂₅ ]*[1/(125-25)]*10 ⁶ ; The weight and volume of the sintered body were measured to calculate the density of the sintered body, and by optical The microscope (OM) is used to observe the microstructure, and it is up to the data to judge whether the composition is satisfactory.

The above sample formulation can be further formed into a laminated ceramic capacitor by the following method: 10 parts by weight of methyl methacrylate, 30 parts of methyl ethyl ketone/ethanol solvent, and butyl benzyl phthalate are added to 100 parts by weight of the formula powder. The organic binder composed of 4 parts and the like is uniformly mixed in a ball mill for 16 hours to prepare a porcelain slurry for casting molding, and then the porcelain slurry is placed in a coating machine to uniformly coat the porcelain slurry on the substrate. Each time the dielectric layer film is about 20~30μm thick, after drying at 80°C, the copper electrode material component is printed as the electrode layer of copper, so after repeated times to reach the required thickness and number of layers, The shaped body is then cut into a 4.0 ^L × 2.0 ^W mm green embryo wafer, which is first degreased at 600 ° C for 80 hours and then sintered at 960 to 1000 ° C for 3 hours. The sintered wafer size is about 3.2 ^L ×1.6 ^W mm, after being baked by the copper outer electrode, according to the following test conditions: frequency 1MHz, test voltage 1Vrms, measure DF value and capacitance value and calculate its dielectric constant ε value; charge with DC voltage 50V, 1 After a minute, measure the insulation resistance value; increase at a rate of 100V per second The voltage is measured, and the breakdown voltage is measured. The capacitance coefficient of capacitance is measured on the basis of the capacitance value of 25 ° C to completely evaluate the electrical characteristics of the multilayer ceramic capacitor. The results of this example are shown in Table (3).

The invention has a dielectric constant of 20 or less, a temperature coefficient of capacitance conforming to the COJ specification available to the enterprise (ie, -55 ° C to 125 ° C, 0 ± 120 ppm), a DF value (ie, a dissipation factor tan δ) of 0.001 or less, and an insulation resistance of 1×. 10 ¹¹ Ω or more, and the sintered density is 3.10 g/cm ³ or more. In the sample of Table (2), except for the samples of 1, 6, 7, 14, 19, 22, 23, 24, 25, 26, etc., the other samples can meet the objectives of the present invention, so the following is the scope of the request. The reason is as follows: As shown in the sample 1, when frit = 2 parts by weight, the DF value is too high and the sintered density is lower than the target value, as shown by the sample 6, when frit = 25 parts by weight, sintering produces stickiness. The film phenomenon can not measure the electrical property, indicating that the glass frit is excessive, and the frit=4~20 parts by weight can meet the target value, so the optimum amount of frit is 4% ≦frit≦20%.

Samples 7 to 26 are mainly used to adjust the ratio of MgO, CaO, SiO ₂ , ZrO ₂ and TiO ₂ of the first component to find the optimum range, in which the sample can meet the electrical characteristics of the target, the sintered density, and Microscope structure.

As shown by the samples 7 and 14, when the MgO = 30 ^m / _o , the DF value is too high and does not meet the characteristic requirements. Or when MgO=85 ^m / _o , there is a phenomenon of DF failure. When MgO=35 ^m / _o ~80 ^m / _o , each property satisfies the target value, so the optimum range of MgO is 35 ^m / _o ≦MgO ≦80 ^m / _o .

As shown in samples 7 and 14, when CaO = 70 ^m / _o , the DF value deviates from the target value. When CaO = 15 ^m / _o , the DF value also deviates from the target value, when CaO = 20 ^m / _o ~ 65 ^m / _o , each property meets the target value, so the optimum range of CaO is 20 ^m / _o ≦ CaO ≦ 65 ^m / _o .

As shown by the samples 19 and 22, when SiO ₂ = 35 ^m / _o , the temperature coefficient deviates from the target value, and when SiO ₂ = 95 ^m / _o , the temperature coefficient also deviates from the target value when SiO ₂ = 40 ^m / _o ~ At 90 ^m / _o , each property satisfies the target value, so the optimum range of SiO ₂ is 40 ^m / _o ≦ SiO ₂ ≦ 90 ^m / _o .

As shown by the samples 23 and 24, when ZrO ₂ = 0 ^m / _o and 40 ^m / _o , the former has a DF value which is too high and the IR is not good, and the latter also has a phenomenon that the DF value is too high and does not meet the characteristic requirement, when ZrO _{When 2} = 5 ^m / _o ~ 35 ^m / _o , each property satisfies the target value, so the optimum range of ZrO ₂ is 5 ^m / _o ≦ZrO ₂ ≦ 35 ^m / _o .

As shown by the samples 25 and 26, when TiO ₂ = 0 ^m / _o , the temperature coefficient is too high to exceed the target value, and when TiO ₂ = 30 ^m / _o , there is a phenomenon that the IR is not far from the target value, when TiO _{When 2} = 5 ^m / _o ~ 25 ^m / _o , each property satisfies the target value, so the optimum range of TiO ₂ is 5 ^m / _o ~ 25 ^m / _o .

Claims (10)

A low dielectric constant dielectric porcelain powder composition which is ultra-low temperature sintered in a reducing atmosphere, and its composition comprises 100 parts by weight including a mole MgO, b mole CaO, c mole SiO ₂ , d mole ZrO ₂ and e Mo Er TiO ₂ , wherein a+b=1, and 0.35≦a≦0.80, 0.20≦b≦0.65, 0.40≦c≦0.90, 0.05≦d≦0.35, 0.05≦e≦0.25 constitute the first component, the first The composition is calcined to form CaMgSi ₂ O ₆ , Ca ₂ MgSi ₂ O ₇ , Ca ₂ Zr ₅ Ti ₂ O ₁₆ , CaTiO ₃ and 4 to 20 parts by weight and includes Li ₂ O, BaO, SiO ₂ , ZnO, and B. A glass frit of the second component of ₂ O ₃ is combined to form the dielectric porcelain powder composition. A low-k dielectric porcelain powder composition which is ultra-low temperature sintered in a reducing atmosphere as described in claim 1, wherein each component of the first component is Mg(OH) ₂ (magnesium hydroxide) Or MgCO ₃ (magnesium carbonate), CaCO ₃ (calcium carbonate), SiO ₂ (yttria), ZrO ₂ (zirconia), TiO ₂ (titanium oxide) as starting materials, wet mixing in a ball mill for 16 hours, pouring After drying, it is calcined in a kiln at a high temperature of 1050 ° C or higher for 2 hours, and the calcined material is the CaMgSi ₂ O ₆ , Ca ₂ MgSi ₂ O ₇ , Ca ₂ Zr ₅ Ti ₂ O ₁₆ , CaTiO ₃ phase, etc. The ceramic powder is formed by finely grinding to 1.0 μm or less. The low dielectric constant dielectric powder composition for ultra-low temperature sintering in a reducing atmosphere according to claim 1, wherein the glass frit of the second component has an approximate composition of 0% by weight ≦ Li ₂ O ≦ 25%, 10% ≦ BaO ≦ 60%, 5% ≦ SiO ₂ ≦ 40%, 0% ≦ ZnO ≦ 30%, 5% ≦ B ₂ O ₃ ≦ 45%. The low dielectric constant dielectric porcelain powder composition which is ultra-low temperature sintered in a reducing atmosphere as described in claim 3, wherein each component of the glass frit in the second component is weighed, mixed, and baked. After drying, it is melted by water at 1200 ° C and finely ground to 1.5 μm or less. Method for preparing low dielectric constant dielectric porcelain powder composition resistant to reduction atmosphere and ultra-low temperature sintering, comprising ceramic ceramic powder and Li ₂ O-BaO-ZnO-SiO ₂ -B ₂ O ₃ glass frit at room temperature The ceramic powder is formed by wet mixing, wherein the ceramic porcelain powder is formed from the ceramic ceramic powder as set forth in claim 2 of the patent application. Method for preparing low dielectric constant dielectric porcelain powder composition resistant to reduction atmosphere and ultra-low temperature sintering, comprising ceramic ceramic powder and Li ₂ O-BaO-ZnO-SiO ₂ -B ₂ O ₃ glass frit at room temperature Wet mixing, wherein the glass frit is the glass frit formed as in item 4 of the patent. A temperature-compensated multilayer ceramic capacitor made of a low-k dielectric sintered porcelain powder composition which is resistant to a low-temperature sintering in a reducing atmosphere, and the composition is composed of 100 parts by weight of MgO-CaO-SiO ₂ -ZrO ₂ -TiO ₂ a component, the first component is calcined to form a phase of CaMgSi ₂ O ₆ , Ca ₂ MgSi ₂ O ₇ , Ca ₂ Zr ₅ Ti ₂ O ₁₆ , CaTiO ₃ , and 4 to 20 parts by weight of a second component glass frit The composition to be compounded is further added with an organic binder in the composition, and uniformly mixed in a ball mill to prepare a porcelain slurry for casting molding, and the porcelain slurry is uniformly coated on the substrate, dried, and then printed. The inner electrode material is a laminated ceramic capacitor which is sintered several times to reach the ceramic structure required for the laminated ceramic capacitor. A temperature-compensated multilayer ceramic capacitor made of a low-k dielectric sintered porcelain powder composition having a reducing atmosphere atmosphere and a reductive atmosphere according to claim 7, wherein the second component of the glass frit is approximated It is 0% ≦ Li ₂ O ≦ 25%, 10% ≦ BaO ≦ 60%, 5% ≦ SiO ₂ ≦ 40%, 0% ≦ ZnO ≦ 30%, 5% ≦ B ₂ O ₃ ≦ 45%. A temperature-compensated multilayer ceramic capacitor made of a low-k dielectric sintered porcelain powder composition having a reducing atmosphere and a low-temperature-sintering atmosphere as described in claim 7, wherein the organic binder is composed of polymethyl methacrylate , butanone / ethanol solvent, butyl benzyl phthalate and other components. A temperature-compensated multilayer ceramic capacitor made of a low-k dielectric sintered porcelain powder composition which is resistant to a reducing atmosphere and has a reductive atmosphere as described in claim 7, wherein the internal electrode material is made of copper.