TWI393693B - A low-fire dielectric composition - Google Patents

Description

Low temperature co-fired dielectric composition

The present invention relates to a low temperature co-fired dielectric composition, in particular to a dielectric ceramic material, the dielectric composition of the present invention can be sintered and compacted at a low temperature, and thus can be combined with a low melting point, high conductivity metal conductor such as silver. And copper co-fired into a dielectric filter product having an inner conductor layer or a strip line type, and has characteristics of high dielectric constant and low dielectric loss.

Reducing the component size is an important issue in current research and development. In order to meet this demand, electronic components of a multi-layer structure have been developed on the market to increase volumetric efficiency, so the filter is also moving toward multilayer and miniaturization. However, in a multilayer filter, it must be co-fired with a low-resistance metal conductor such as silver or copper, but the copper conductor must be sintered in an oxygen-free atmosphere to avoid the formation of copper oxide, but in an oxygen-free atmosphere, the ceramic The removal of the organic binder in the powder is difficult, and the production cost is increased. While the silver conductor can be sintered in the atmosphere, the melting point is 962 degrees Celsius (° C.), so the ceramic component must be sintered below the melting point of the silver. carry out. Therefore, the development of low temperature sinterable dense dielectric materials becomes very important.

In order to meet the needs of miniaturization of filters, the following characteristics must be met in the selection of ceramic materials: (1) have a high dielectric constant (K), usually K values between 10 and 100, the main reason is the size of the filter The reduction is related to K ^1/2 , and the higher the K, the smaller the size of the filter. (2) With a small dielectric loss (tan δ), the smaller the dielectric loss, the higher the quality factor can be obtained to facilitate the selection of the resonant frequency.

Among the different dielectric ceramic materials, various ceramic materials known to meet the above requirements are: TiO ₂ , Ba ₂ Ti ₉ O ₂₀ , BaTi ₄ O ₉ , ZrO ₂ -SnO ₂ -TiO ₂ , Ba(Zn _{1/ 3} Ta _2/3 )O ₃ , and (Ba,Pb)Nd ₂ Ti ₅ O, however, these ceramic materials have sintering temperatures above 1300 ° C (° C) and cannot be co-fired with highly conductive metal conductors such as silver. Therefore, in order to lower the sintering temperature to 962 degrees Celsius (° C.) or lower, a generally known solution is to chemically produce a fine powder, add a sintering aid to a ceramic material, or add a glass having a low softening point to assist sintering. The addition of a sintering aid consisting of manganese carbonate and copper oxide to pure titanium dioxide is the method used in this experiment.

The microwave dielectric ceramic material mentioned in U.S. Patent No. 5,449,652 is composed of Bi _(2-x) (Zn _(2+y)/3 Nb _(4/3) )O _(7-3x/2+y/3) , of which 0.24 <x<0.333, 0.120<y<0.3; and Bi _(1-x) Ca _(x) (Zn _(2+y)/3 Nb _(4/3) )O _{(7-3x/2+y/3+xz/-z)} , Where 0<x<0.667, 0<y<0.30, 0<z<0.2. The microwave dielectric ceramic material has a dielectric constant of 100 (@7 GHz), a quality factor of 7000 (@7 GHz), and a resonance frequency temperature coefficient of 10 ppm/°C.

The low dielectric ceramic material mentioned in U.S. Patent No. 4,672,152 is composed of 50 to 95 weight percent (wt%) of crystallized glass and 50 to 5 weight percent (wt%) of ceramic filler. The crystallized glass component added is 5 to 20 weight percent (wt%) Li ₂ O, 60 to 90 weight percent (wt%) SiO ₂ and 1 to 10 weight percent (wt%) Al ₂ O ₃ . The ceramic filler consists of SiO ₂ and Al ₂ O ₃ . The dielectric material obtained has a dielectric constant between 5.1 and 6.0.

The low dielectric ceramic material mentioned in U.S. Patent No. 4,755,490 is from 10 to 50 weight percent (wt%) Al ₂ O ₃ , 0 to 30 weight percent (wt%) fused SiO ₂ and 50 to 60 weight percent ( Wt%) consists of glass. The composition of the glass was 4 wt% CaO, 12 wt% (wt%) MgO, 29 wt% (wt%) B ₂ O ₃ and 42 wt% (wt%) SiO ₂ . The dielectric ceramic material can be sintered at a temperature lower than 1000 degrees Celsius (° C.), and has a dielectric constant of 4.5 to 6.1 and a linear thermal expansion coefficient of 3.9 to 4.2×10 ^-6 K ^-1 .

In U.S. Patent No. 5,415,945, the composition of the high dielectric constant ceramic material is 75 to 85 mole percent (mol%) Pb(Ni _1/3 Nb _2/3 )O ₃ , 0 to 15 mole percent ( Mol%) PbTiO ₃ , 5 to 16.5 mole percent (mol%) Pb(Zn _1/2 W _1/2 )O ₃ and Pb(Cu _1/3 Nb _2/3 )O ₃ . The sintering temperature is 1000 degrees Celsius (° C.), and the resulting dielectric constant is between 1000 and 4000.

The high dielectric ceramic material mentioned in U.S. Patent No. 5,262,368 is composed of BaTiO ₃ , BaCuO ₂ , WO ₃ and MoO ₃ . The sintering temperature is 1150 degrees Celsius (° C.), and the resulting dielectric constant is 2000 to 3000 (@1 KHz), and the dielectric loss is 2.5 to 16% (%) (@1 KHz).

The high dielectric ceramic material mentioned in U.S. Patent No. 5,461,014 is composed of Pb(Mg _1/3 Nb _2/3 )O ₃ and BaCuO ₂ . The sintering temperature is 1050 degrees Celsius (° C.), and the resulting dielectric constant is 7000 to 8000 (@1 KHz), and the dielectric loss is less than 3 percent (%).

The low temperature sintered microwave dielectric material composition mentioned in U.S. Patent No. 6,309,993 is 20 to 90 volume percent (vol%) of borosilicate glass and 80 to 10 volume percent (vol%) of TiO ₂ . It can be sintered at temperatures below 1000 degrees Celsius (°C), resulting in a dielectric constant of 20 to 45 (@7 GHz) and a quality factor of 1000 to 1300 (@7 GHz).

The low-temperature sintered dielectric material mentioned in U.S. Patent No. 6,159,883 has a composition of 30 to 90 volume percent (vol%) of Ca-Pb-Al-Zn-B-Si glass and 70 to 10 volume percent (vol%) of oxide. . The sintering temperature is 800 to 1000 degrees Celsius (° C.), the resulting dielectric constant is 6 to 10, and the dielectric loss is 0.01% (%) to 0.05% (%) (@1 MHz).

It can be seen from the above description that ceramic materials having low sintering temperature, high dielectric constant and low dielectric loss are still urgently needed in the industry, and the present invention has been developed for this requirement.

SUMMARY OF THE INVENTION The object of the present invention is to provide a novel low temperature co-fired dielectric composition which can be sintered at a low temperature and has high dielectric constant and low dielectric loss.

The object of the present invention is also that the ceramic composition of the low-temperature co-fired dielectric composition can be sintered at a low temperature and is dense, so that it can be compatible with a low melting point, low-impedance conductor, and co-fired with a low melting point and a highly conductive metal. The process of lamination provides the laminated dielectric ceramic components required by the market.

In order to achieve the objects and other characteristics of the present invention, the present invention provides a low temperature co-fired dielectric composition in a technical solution: a low temperature co-fired dielectric composition comprising 80 to 96.5 weight percent (wt%) a composition of titanium dioxide (TiO ₂ , rutile) and 3.5 to 20 weight percent (wt%) of manganese carbonate and copper oxide sintering agent, the composition of which can obtain a relative sintered density at 875 to 925 degrees Celsius (° C.) 95% or more (%) or more; in addition, according to the composition of the composition of the green embryo, after sintering compaction, a dielectric constant of 70 to 101 and a dielectric loss of less than 0.5% (%) can be obtained at 1 MHz; The composition of the sintering aid comprises 9 to 50 weight percent (wt%) manganese carbonate and 50 to 91 weight percent (wt%) copper oxide.

In another aspect of the invention, the low temperature co-fired dielectric composition, wherein the slurry further used to form the low temperature co-fired dielectric composition component comprises 70 to 85 weight percent (wt%) as described above a composition of the low-temperature co-fired dielectric composition, and 15 to 30 weight percent (wt%) of the organic vehicle; wherein the organic carrier is a mixed slurry of an organic solvent, an organic binder, and an organic plasticizer; Using the slurry described in this subsection, the resulting embryos can be sintered and densified at less than 925 degrees Celsius (° C.).

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

First, as is known in the industry, pure titanium dioxide (TiO ₂ ) has good microwave characteristics, such as high dielectric constant (~100 @GHz) and high quality factor (~10000 @GHz), etc., only the sintering temperature of pure titanium dioxide needs It can be sintered and densified up to 1100 degrees Celsius (°C). At such a high sintering temperature and an oxygen-requiring atmosphere, it is necessary to use a precious metal as an electrode, such as a silver-palladium alloy, when it is fabricated into a laminated ceramic component.

Therefore, the inventors of the present invention have found that the addition of a mixture of manganese carbonate and copper oxide in pure titanium dioxide (TiO ₂ ) can effectively lower the sintering temperature to below 900 ° C (° C.), so that cheaper silver can be used instead of expensive silver. Palladium alloy to reduce manufacturing costs.

In particular, the present invention is a novel low-temperature co-fired dielectric composition composed of titanium dioxide (TiO ₂ , rutile) mixed with different proportions and a sintering aid (MnCO ₃ -CuO, MC). The ratio of the composition of the sintering aid is not particularly limited and can be adjusted depending on the nature of the desired product.

In the practice of the present invention, a preferred low-temperature co-fired dielectric composition contains 80 to 96.5 weight percent (wt%) of titanium dioxide (TiO ₂ , rutile) and 20 to 3.5 weight percent (wt%) of a combustion aid. (MC); In addition, the sintering aid has a preferred composition of manganese carbonate and copper oxide (MnCO ₃ -CuO) in a weight ratio of (1:3) and (1:6).

The low temperature co-fired dielectric composition of the present invention can be applied to laminated ceramic elements. In this application, the low temperature co-fired dielectric composition is mixed with an organic vehicle to form a slurry comprising 70 to 85 weight percent (wt%) of a low temperature co-fired dielectric composition and 15 to 30 weight percent (wt %) an organic carrier; a green sheet is obtained by a doctor blade forming process, and then a laminated ceramic component is obtained by a conventional technique such as screen printing conductor paste, lamination and co-firing. The low temperature co-fired dielectric composition comprising 3.5 to 20 weight percent (wt%) of a mixture of manganese carbonate and copper oxide (MnCO ₃ -CuO) and 96.5 to 80 weight percent (wt%) of titanium dioxide (rutile) .

Further, in a method of preparing a dielectric ceramic component of the present invention, the powder of the low temperature co-fired dielectric composition is formed into a green embryo, and the green embryo is densified at a temperature lower than 962 degrees Celsius (° C.). Wherein, the densification step comprises a first stage degreasing and a second stage sintering, and is preferably carried out in air. As is known to those skilled in the art, the degreasing stage is to remove the organic binder in the green embryo, and the sintering stage can densify the embryo body; in the present invention, the preferred sintering conditions are in the range of 875 to 925 Celsius. Degree (°C) is held for 60 minutes; the dielectric ceramic component obtained by the densification step has a dielectric constant of 70 to 101 at 1 MHz and a dielectric loss of less than 0.5% (%), thus meeting the industry's The need for electrical constants and low dielectric losses.

The description of the prior art and the following detailed description of the preferred embodiments are illustrative and illustrative. The embodiments of the invention described below are intended to further illustrate the invention but not to limit the invention. The scope of invention patents. All the alternatives and modifications known to those skilled in the art are still included in the spirit and scope of the present invention and are combined with Chen Ming.

Please refer to the material composition, process conditions and properties of the embodiments of the present invention as shown in the first to fourth figures. among them;

Example 1: First, manganese carbonate: copper oxide, according to the proportion of the weight percentage of 1:1, the purity of 99% (%) or more of manganese carbonate, oxidized steel and other ceramic powder a total of 40 grams (g), will be formulated A good powder is added to a 100 ml (CC) plastic (PE) bottle containing 32 ml of (CC) 1-propyl alcohol and 46 g (g) alumina grinding balls, and cantilevered in a three-degree space. After mixing for 2 hours, the powder is dried in an oven at 80 ° C (°C). The dried powder is evenly ground in a mortar and pestle, placed in a zirconium dioxide (ZrO ₂ ) crucible and placed in a high temperature furnace. Medium, heated to 740 degrees Celsius (°C/min) per minute, heated to 740 degrees Celsius (°C) for 2 hours, calcined and then furnace cooled, and the calcined powder was added to have been filled with 500 g of zirconium dioxide ( ZrO ₂ ) Grinding ball, 55 ml (CC) of 1-propyl alcohol and 0.15 ml (CC) dispersant (Darvan C) in 250 ml (CC) plastic (PE) bottles, after ball milling for 72 hours, It is dried in an oven at 80 ° C (° C.), and the dried powder is ground in a mortar and pestle to obtain the desired sintering aid (MC).

3.5% by weight (wt%) co-firing agent (MC) plus 96.5 weight percent (wt%) titanium dioxide (TiO ₂ ), 5 weight percent (wt%) combustion aid (MC) plus 95 weight percent (wt% Titanium dioxide (TiO ₂ ), 10 weight percent (wt%) combustion aid (MC) plus 90 weight percent (wt%) titanium dioxide (TiO ₂ ), 15 weight percent (wt%) combustion aid (MC) plus 85 weight percent (wt%) titanium dioxide (TiO ₂ ) and 20 weight percent (wt%) combustion aid (MC) plus 80 weight percent (wt%) titanium dioxide (TiO ₂ ) ratio, the amount of the combustion aid (MC ) 20 g (g) of titanium dioxide (TiO ₂ ) powder having a purity of 99% or more by weight, and put into n-propanol (1) containing 46 g (g) of alumina grinding balls and 16 ml of (CC). Propyl alcohol) and 5 weight percent (wt%) polyethylene glycol 200 (PEG 200) in 100 ml (CC) plastic (PE) bottles, mixed in a three-degree space cantilever mixer for 2 hours, The oven is dried at 80 degrees Celsius (° C.), and the dried powder is ground with a mortar and pestle to form a powder of the alternate low temperature co-fired dielectric composition.

0.8 g (g) of the powder of the standby low-temperature co-fired dielectric composition was weighed, placed in a circular die having a diameter of 13 mm, and held at a pressure of 90 mbar (MPa) for 15 seconds ( Sec), the powder is tableted into a green embryo.

The prepared raw embryos are placed in a high-temperature furnace and heated to a temperature of 3 degrees Celsius (°C/min) to 500 degrees Celsius (°C) for one hour in an air atmosphere to remove organic matter in the embryo. The binder is then heated to a temperature of 5 degrees Celsius (°C/min) to 875 degrees Celsius (°C), 900 degrees Celsius (°C) or 925 degrees Celsius (°C). After holding for 1 hour, the furnace is cooled to form a relative sintering. Densified densified sintered test piece.

The sintered test piece was obtained by using the Archimedes principle to obtain the relative sintered density of the sintered body, and the relative sintered density obtained in this example was 3.5 weight percent (wt%) of the 900 degree Celsius (° C.). Agent (MC) plus 96.5 weight percent (wt%) titanium dioxide (TiO ₂ ), 5 weight percent (wt%) combustion aid (MC) plus 95 weight percent (wt%) titanium dioxide (TiO ₂ ) test piece and The test pieces of each of the added ratios of 925 ° C (° C.) can make the relative sintered density higher than 95% (%) or more, which is consistent with the results of the scanning electron micrograph of the fracture surface of the sintered body.

The upper and lower surfaces of the sintered test piece are coated with a layer of low-temperature silver glue, and dried in an oven at 80 ° C (° C.), and the capacitance value (Cp) and dielectric loss (tan δ) are measured by HP4192. The formula finds the dielectric constant (K).

Cp=(K ε ₀ A)/t where ε ₀ is the vacuum dielectric constant, t is the distance between the two electrode plates, and A is the area of the electrode plate.

The results obtained in this first embodiment are shown in the first figure (as indicated by number 1 to number 15).

Example 2: In this example, except for the sintering aid, wherein the composition is changed to manganese carbonate: the weight percentage of copper oxide is equal to 1:3, the other processes and measurement procedures are the same as in the first embodiment. The relative sintered density obtained in this example was 15 weight percent (wt%) of the sintering aid (MC) plus 85 weight percent (wt%) of titanium dioxide (TiO ₂ ) and 20 weight percent (in terms of 875 degrees Celsius (° C.). The wt%) co-firing agent (MC) plus 80% by weight (wt%) of titanium dioxide (TiO ₂ ), the other relative sintered density is higher than 95% (%) or more, the dielectric constant is 70 to 98, dielectric The losses are all less than 0.5% (%); the results obtained in this second embodiment are listed in the second figure (as indicated by number 16 to number 30).

Example 3: In this example, except that the composition of the sintering aid was changed to manganese carbonate: the weight percentage of copper oxide was equal to 1:6, the other processes and measurement procedures were the same as in the first embodiment. The relative sintered densities obtained in this example are all greater than 95% (%), the dielectric constant is 74 to 98, and the dielectric loss is less than 0.5% (%); the results obtained in the third embodiment are listed in the first Three figures (as indicated by number 31 to number 45).

Embodiment 4: In this embodiment, except that the composition of the sintering aid is changed to manganese carbonate: the weight percentage of copper oxide is equal to 0:1, the other processes and measurement procedures are the same as in the first embodiment. The relative sintered densities obtained in this example are all greater than 95% (%), and the dielectric constant is 77 to 101, but the dielectric loss is much greater than 0.5% (%); the results obtained in this embodiment 4 are listed. In the fourth picture (as indicated by number 46 to number 60).

In the above-mentioned Example 2 and Example 3, all low-temperature co-fired dielectric compositions of titanium dioxide (TiO ₂ ) plus combustion aid (MC) flux can be completed at less than 900 ° C (° C). Densification above percentage (%). Since the sintering temperature required to complete the high densification is compatible with the low melting point, low impedance conductor such as silver, all of the dielectric components in the second and third embodiments can be co-fired with the silver conductor to form a laminate. A component of a low temperature co-fired dielectric composition.

In the process, the components of the laminated low-temperature co-fired dielectric composition are prepared by firstly adding the above-mentioned low-temperature co-fired dielectric composition to an organic solvent (such as toluene and ethanol) and an organic binder (such as polyethylene). Butanal (PVB) and a plasticizer (such as dibutyl acid (DBP)) are mixed to form a slurry, and a green sheet having a thickness of about 125 μm is formed by doctor blade forming, and then cut into 10 pieces by punching. Centrifugal (cm) square raw germ flakes.

A hole is punched in the green sheet by a mold having a pore size of about 125 μm, and a conductor paste such as silver is filled into the hole by screen printing. In addition, the conductor tracks on the green sheets are also screen printed.

The screen printing and the well-filled green embryo sheets are sequentially stacked, and laminated to form a green layer of a low-temperature co-fired dielectric composition, and the lamination conditions are 60 to 100 degrees Celsius (° C.) and 1000 to 3000 per gallon. Inch/lb (psi). Finally, the green embryos of the laminated low-temperature co-fired dielectric composition are densified by degreasing and co-firing in an air atmosphere.

In addition, the low-temperature co-fired dielectric composition in each embodiment can also be made into a ceramic body of various uses such as dry pressing, cold equalizing and hot equalizing. Taking dry pressure as an example, the low-temperature co-fired dielectric composition can be mixed with water and a binder (such as polyvinyl alcohol (PVA)), and after spray granulation, the fluidity of the powder is improved, followed by dry pressing and de-esterification. The finished ceramic body can be made into a low-temperature co-fired dielectric composition by sintering.

In summary, the present invention has achieved the desired effect under the prior art structure and manufacturing method, and is not easily understood by those skilled in the art; further, the present invention has not been disclosed before the application. Its progressive and practical nature has been consistent with the application requirements of the invention patent, and the invention application has been filed according to law.

The first figure is the material composition, process conditions and properties of the first embodiment of the present invention.

The second figure is the material composition, process conditions and properties of the second embodiment of the present invention.

The third figure is the material composition, process conditions and properties of the third embodiment of the present invention.

The fourth figure is the material composition, process conditions and properties of the fourth embodiment of the present invention.

Claims (6)

A low temperature co-fired dielectric composition comprising 80 to 96.5 weight percent (wt%) of titanium dioxide (TiO ₂ , rutile) and 3.5 to 20 weight percent (wt%) of manganese carbonate and copper oxide sintering agent Composition, the composition of the composition can obtain a relative sintered density of 95% (%) or more at 875 to 925 degrees Celsius (°C). The low temperature co-fired dielectric composition of claim 1, wherein the sintering aid comprises 9 to 50 weight percent (wt%) manganese carbonate and 50 to 91 weight percent (wt%) copper oxide. A slurry of a low temperature co-fired dielectric composition component comprising 70 to 85 weight percent (wt%) of a low temperature co-fired dielectric composition, and 15 to 30 weight percent (wt%) of an organic vehicle; wherein the low temperature The co-fired dielectric composition is composed of 80 to 96.5 weight percent (wt%) of titanium dioxide (TiO ₂ , rutile) and 3.5 to 20 weight percent (wt%) of manganese carbonate and copper oxide sintering agent, and this The composition of the composition can be obtained at a relative sintered density of 95% (%) or more at 875 to 925 degrees Celsius (°C). The slurry of the low-temperature co-fired dielectric composition component according to claim 3, wherein the organic carrier is a mixed slurry of an organic solvent, an organic binder, and an organic plasticizer. The slurry of the low-temperature co-fired dielectric composition component according to claim 3, wherein the slurry, the raw embryo made thereof, can cause the green embryo to be sintered at a temperature lower than 925 degrees Celsius (° C.). . The low-temperature co-fired dielectric composition according to claim 1, wherein the raw material is composed of a raw material, and a dielectric constant of 70 to 101 and a transmittance of less than 0.5% (%) can be obtained at 1 MHz after sintering and densification. Dielectric loss.